Merit Sensor AP Series in Pharmaceutical and Medical Applications

In the field of medical science, pressure is an indispensable physiological parameter. In a range of environments and applications involving both liquids and gases, precise measurement is essential for diagnostic accuracy and therapeutic efficacy.1 Merit Sensor Systems, a leader in MEMS piezoresistive pressure sensing, provides high-performing solutions for a range of industries.2 Among their innovative products, the AP Series pressure sensors are specially designed for pharmaceutical and medical applications.

In this article, we examine two configurations of the AP Series pressure sensor:

  1. AP-Series with polycarb port, or ferrule port for direct backside media contact
  2. AP-Series with gel-port plus dielectric gel for enhanced media biocompatibility

This is followed by an exploration into their application in various medical and pharmaceutical processes, including the integration of these sensors in Merit Medical’s Blue Diamond Digital Inflation Device.

The AP-Series: Examining the Sensor’s Dual Configurations

Utilizing a piezoresistive Wheatstone bridge with a chemically etched silicon diaphragm, both configurations of the AP-Series pressure sensor are engineered to provide precise pressure measurements in both static and dynamic environments.3 Each sensor, capable of measuring both liquids and gases, ensures cost-effectiveness without compromising on functionality.

 

Key Features

  • Wide Pressure Range: The AP-Series sensors cover several apressure ranges from 0 to 1000 psi (0 to 70 bar) accommodating a variety of medical and pharmaceutical applications, from vacuum aspiration applications, to low pressure blood pressure, up to high pressure injection and pump control applications. 4
  • High Accuracy: The sensors offer a trimmed output signal with minimal offset for easy amplification with an operational amplifier. This is achieved by calibrating the sensors using laser-trimmed resistors.4
  • Robustness: Designed to withstand high burst pressures, these sensors are reliable even in challenging environments. Their compact geometry and durability make them suitable for integration into a multitude of medical devices. The design is suitable for single-use disposable applications, as well as long term applications.
  • Sterilization Compatibility: These sensors are compatible with sterilization processes, including ETO, Gamma-ray, and autoclave, ensuring they meet the rigorous standards required in medical applications.
  • Easy Integration: With options for flexible or cable interfaces, the AP-Series sensors can be seamlessly integrated into existing systems.
  • High Resolution and Frequency: These sensors deliver a pure analog signal to allow exceptional performance in high-resolution and high-frequency applications.3
  • Reliable Through Backside: Both configurations ensure that the active side of the sensing element (wirebonds and conductor traces) remains protected from direct contact with the media, enhancing the sensor’s longevity and reliability.

Applications

The AP-Series sensors, which have a polycarb and ferrule port as well as direct media contact on the backside, are suited for measuring liquid and gas pressure and flow in medical and pharmaceutical equipment. Typical applications include:

  • Mixing Machines: Guaranteeing accurate pressure control during the mixing of pharmaceuticals.
  • Analysis Machines: Precise pressure monitoring in laboratory equipment for fluid analysis.
  • Fluid Treatment and Processing: This is used in systems that require precise pressure regulation to ensure the integrity of the fluid being processed.
  • Aseptic Liquid Processing: Key when it comes to maintaining sterility and preventing contamination during the production of pharmaceuticals.

The AP-Series pressure sensors feature enhanced media compatibility with gel-port and dielectric gel, reducing wetted materials and making them ideal for challenging environments in pharmaceutical and medical applications, including:

  • Bio-Decontamination Equipment: Monitoring pressure in systems that are created to sterilize equipment and facilities.
  • Bioreactor Monitoring, Chromatography, and Flow Filtration: Ensuring reliable pressure measurements in critical biocompatibility processes.
  • Laboratory Equipment: Providing precise pressure data in equipment used for sophisticated chemical analyses and experiments.

Integration in the Blue Diamond Digital Inflation Device

A notable application of the AP-Series pressure sensors is in Merit Medical’s Blue Diamond Digital Inflation Device and Fluid Dispensing Syringe. This device is designed to inflate and deflate balloon angioplasty catheters and other interventional devices. It can also be used to accurately measure the pressure and duration of inflation while simultaneously dispensing fluids into the body and monitoring pressure levels.5

Features of the Blue Diamond Digital Inflation Device

  • Integral Pressure Transducer: The AP-Series sensors integrated into this device provide exact pressure measurements essential for the safe and effective performance of angioplasty procedures.5
  • Microcomputer and Back-Lit LCD: These features facilitate precise control and easy monitoring of the inflation process in low and no-light situations.5,6
  • Threaded Plunger Assembly and High-Pressure Extension Tube: Combined with Merit Sensor’s robust pressure sensors, these components ensure the device can generate and monitor positive and negative pressures over a range of -0.4 to +30 ATM/BAR (-6 to 441 psi).5
  • Data Recording and Recall: This feature of the syringe electronics allows users to record and recall prior inflation information, making it ideal for procedure data tracking.7

Merit Sensor Systems: Pharmaceutical and Medical Solutions You Can Trust

Merit Sensor Systems’ AP Series pressure sensors are a top-tier option for a diverse suite of pharmaceutical and medical applications. The two configurations—gel-port with direct backside media contact and gel-port with dielectric gel—offer versatility and enhanced media compatibility while guaranteeing precision, robustness, and cost-effectiveness. Moreover, their compliance with stringent medical standards and integration into critical devices, such as Merit Medical’s Blue Diamond™ Digital Inflation Device, highlight their reliability and adaptability in demanding medical environments. To find out more about how these devices can be integrated into your workflow, contact a member of the Merit Sensor System’s team today.

References and Further Reading

    1. Casey, V., et al. (2011). Pressure Measurement at Biomedical Interfaces. Applied Biomedical Engineering. doi.org/10.5772/21855
    2. Merit Sensors. [Online] Applications. Available at: https://meritsensor.com/ (Accessed on 26 May 2024).
    3. Merit Sensor. Data Sheet: AP Series. Available at: https://meritsensor.com/assets/documents/pdf/AP-series.pdf (Accessed on 26 May 2024).
    4. Merit Sensor. [Online] AP Series. Available at: https://meritsensor.com/products/AP-Series/ (Accessed on 26 May 2024).
    5. Merit Medical. Blue Diamond™ Digital Inflation Device. Available at: https://cloud.merit.com/catalog/IFUs/407737001.pdf (Accessed on 02 July 2024).
    6. Merit Medical. [Online] Blue Diamond™ Digital Inflation Device. Available at: https://www.merit.com/product/blue-diamond-inflation-device/#documents_education (Accessed on 2 July 2024).
    7. Merit Medical. A Global Leader in Inflation. Available at: https://cloud.merit.com/catalog/Brochures/400899001.pdf (Accessed on 2 July 2024).

The Instrumental Role of MEMS Pressure Sensors in Water Conservation

In this interview, AZoSensors speaks to Merit Sensor’s Rick E. Russell about the critical role MEMS pressure sensors will play in water conservation efforts.

Could you describe the role of water in the MEMS pressure sensor manufacturing process and the key reasons behind implementing a water-conservation initiative?

Deionized water is the main ingredient for wafer fabrication processing and is similarly the largest waste product that we have to deal with. We have been prioritizing the sustainability of our operations for a number of years, and both reducing water usage and minimizing water waste have been central to this initiative.

This work also links into our wider organizational goals around sustainability. We believe that as a global leader in healthcare technology, Merit Medical has a major role to play in contributing to a sustainable future. Improving our organization’s sustainability is also key to the success of our overall business strategy.

In what ways does the water-recycling program address the challenges associated with wastewater treatment and disposal during the sensor fabrication process?

Many of our sites are based in desert environments where available water is at a premium, so we strive to conserve as much water as possible.

Our waste naturalization system already balances the wastewater’s pH before we send it down the drain, so we thought it would be worth the investment to see if we could recycle this water instead.

Can you walk us through the steps involved in recycling and reusing wastewater to produce MEMS pressure sensors?

We utilized the Water Risk Filter tool provided in collaboration between the World Wildlife Fund for Nature (WWF) and KFW DEG, and this helped us to understand basin water risk at our operating locations.

Since then, we have identified three manufacturing locations (Tijuana, Mexico; Salt Lake City, Utah; and Pearland, Texas) as water-stressed sites and invested capital over the past three years at these drought-vulnerable operations to allow us to better conserve and store water.

To recycle and reuse wastewater, we essentially pass it through additional filtration cycles and add chemicals to strip away any unnecessary contaminants.

In 2022, we implemented two successful projects of this nature at our Salt Lake City site: a cooling-water recirculation project and a process-water recirculation project within our sensor operations. We are also working on a similar project at our facility in Tijuana, Mexico, which is our second largest site for water consumption and another where a risk of water scarcity has been identified.

Considering the involvement of acids and bases in manufacturing, what measures have been implemented to treat and neutralize wastewater before discharge?

Our waste neutralization system continuously monitors the pH of the contaminated water and balances the pH with the necessary acid or base before discharging the water down the drain.

How does Merit Sensor’s water-saving initiative align with the broader regional efforts to mitigate water usage?

As reported by our CEO in our 2023 Sustainability Report, Merit completed its third year of progress toward our 2030 Operational Sustainability Goals, and we are seeing more evidence of momentum as we consistently reach and surpass each of our targets for energy, water, and greenhouse gas emissions.

Efforts to mitigate water use vary between regions. Water is one of our main environmental challenges and opportunities, so we have worked to better understand the impact of water use at each of our operating facilities and to implement water efficiency programs on a regional level.

These goals and initiatives are addressed at the individual site level, and we can do this by understanding the local and regional water basin activity and stress.

Achieving a ninety percent water recycling efficiency is an ambitious goal. What innovative approaches or technologies are Merit Sensors exploring to reach this objective?

As pointed out in our 2023 Sustainability report, we have other ongoing projects, such as closed-loop water cooling and xeriscaping, that will help us reach our goal. The water recirculation project will also be instrumental in our success in this area.

We have already seen a 17 % decrease in water withdrawal per dollar of revenue earned since 2020, already surpassing our global 2030 targets. This water intensity improvement was primarily driven by water-reduction and efficiency projects, including the use of xeriscaping and installing water-recirculation systems at our largest site in Salt Lake City, Utah.

Can you share some of the critical lessons your team learned throughout the process and how these experiences have influenced your approach to sustainability in other aspects of the company’s operations?

Merit was initially focused on xeriscaping because it was the most straightforward. We knew that fabrication was the biggest culprit for water consumption, but the cost of water does not provide any payback. We learned very quickly that you must spend money to save water. If water costs more than gasoline, then everyone would be focused on saving water.

Does the water-recycling program offer any other potential environmental benefits besides conserving water?

We at Merit believe that spending money to save water would, in turn, save lives. Water is essential for drinking, farming, firefighting, reservoirs and dams, wildlife, and much more. This is also important because several of our sites are located in regions prone to droughts, and any water saved can potentially be used by local communities or amenities.

How do you envision the long-term impact of this initiative on the company’s operations and its contribution to sustainable manufacturing?

Merit is committed to our long-term goals of maintaining our ISO14001 and ISO50001 certifications. This includes not only water but also energy consumption and emissions.

For example, 50 % of our manufacturing sites (Salt Lake City, Utah; Galway, Ireland; Venlo, the Netherlands; and Paris, France) are certified to ISO 50001, and we continually seek to improve our energy management systems.

By implementing this system in our sensor operations and fine-tuning its performance, we are paving the way for similar solutions at other Merit sites to continue reaping the benefits of using water efficiently.

MEMS pressure sensors find applications in various industries. can you elaborate on the quality control measures to ensure recycled water meets the required standards for diverse applications?

Further testing has proven that recycled water does not affect the quality of our MEMS pressure sensors or the operation of our fab. We currently deliver pressure sensors to monitor the pressure in various water applications, such as water meters and tank levels.

Apart from the current water-recycling project, has Merit Sensor integrated other sustainable practices into its manufacturing process?

Merit is focused on three major sustainability goals: decreasing water intensity by 10 %, decreasing energy intensity by 10 %, and decreasing GHG emissions by 15 % by 2030. We are also working towards increasing the proportion of Merit’s energy from renewable sources to 50 % of total usage.

Increasing our use of renewable and carbon-free energy is a key part of our long-term strategy. We have already committed to purchasing 50 % of our total energy from renewable and carbon-free sources by 2030, and given the large amount of energy required by our operations, we also plan to explore opportunities around installing solar panels and the potential of carbon offset credits.

Wider goals include reducing product packaging, transitioning to paper-free systems where possible, and increasing the percentage of waste at our facilities that is recycled.

About the Speaker

Rick joined Merit Sensor in October of 2009 where he managed worldwide sales and business development until he became President of the group in 2013.  He brings many years of organizational management and technical expertise in the area of MEMS silicon fabrication. With more than 25 years of experience managing sales to product development across multiple industries, his knowledge has enabled him to expand the operations to accommodate a number of new customers in their state-of-the-art wafer fab located in Salt Lake City.

Rick studied mathematics and computer science at Eastern Michigan University and received a Bachelor of Science in Electrical-Engineering from Lawrence Technological University.

This article was published by AZo Network.

Key Sensors for eBikes: Boosting Functionality and Safety

For an eBike to achieve maximum performance and safety, whether on the city streets or mountain trails, maintenance of optimal tire pressure is critical. Cutting-edge technologies produced by Merit Sensor empower cyclists to monitor tire pressure in real time, enabling dynamic adjustments to optimize the riding experience.

The Rise of Electric Bicycles

The world experienced a significant “bicycle boom” during the COVID-19 pandemic as the public looked to engage in outdoor exercise and avoid public transportation. To this end, eBikes (bicycles with an electric motor integrated to aid propulsion) emerged as an alternative to traditional manual bicycles, especially in China, the United States, and Germany. 1,2

eBikes have since become more than just an avenue for exercise or a green alternative to transport. Using eBikes allows riders to overcome challenges faced by traditional cyclists, such as incline, distance, and physical exertion, opening cycling to a broader demographic of people, including those with limited fitness and those navigating difficult terrains.3

Tire Pressure

eBike users must ensure optimal tire pressure, which ensures smooth and efficient movement, whereas inadequate pressure can increase resistance, making pedaling more difficult and reducing the distance a user can cycle.

Improper tire pressure also compromises braking and cornering ability, affecting safety and increasing the risk of tire blowouts or punctures.

Standard eBike users may be accustomed to inflating tires to 70 PSI, the standard recommendation, but recommended tire pressures actually vary according to the type of bicycle and tire:

  • Children’s bikes: 20 to 40 PSI
  • Narrow tires (e.g., those used for road bikes) 80 to 130 PSI
  • Medium tires (e.g., hybrid bikes) 50 to 70 PSI
  • Thick tires (e.g., mountain bikes) 30 PSI off-road, 50 PSI on-road

There are other factors that must be considered when determining ideal time pressure, such as riding conditions, rider weight, and personal preference. For example, trail terrain conditions demand pressures from 40 to 70 PSI, while 80 to 130 PSI is optimum for smooth roads.

In addition, for effective distribution of weight, riders should inflate rear tires to two PSI above the front tire, compensating for the extra weight on the rear of most bikes.4,5

Devices for Measuring Pressure

Merit Sensor has manufactured two sensor series to aid eBike users in determining optimum tire pressure: the RS and CMS series.

These devices, compliant with the Restrictions on the Use of Certain Hazardous Substances in Electrical and Electronic Equipment (RoHS), integrate a chemically etched silicon diaphragm with a piezoresistive Wheatstone bridge to provide pressure readings for enhanced safety and performance.

RS Series

Developed in the US, the RS series has been designed to handle a range of pressures from 0 to 500 PSI and represents an uncompensated packaged pressure sensor and transducer.

The RS series is intended for surface-mount devices (SMD) and can be connected to wires or tubes. Its pressure port facilitates a straightforward connection to the tire, ensuring accurate pressure readings for enhanced safety and performance. With its outstanding media compatibility, the RS Series is a versatile and reliable solution for tire pressure monitoring. 6

CMS Series

The CMS Series has an application-specific integrated circuit (ASIC) for calibrating and compensating thermal and non-linearity effects and a compact piezoresistive pressure sensor.

At 6.8 mm by 6.8 mm, it has a wide operational voltage range, exceptional burst pressure, and an energy-efficient mode. This US-manufactured, sensor is ideal for small devices such as tire-pressure monitors and can measure pressures from 2 to 150 PSI. 7

eBike Integration

Merit Sensor technology has been successfully integrated into various tire pressure monitors, as described below.

Real-Time Tire Pressure Sensor

Merit Sensor’s technology can be used inside of a tire pressure sensor device to provide highly accurate pressure data directly to a smart device. The product is easy to install on tube or tubeless tires and allows riders to make informed decisions impacting tire wear, traction, ride comfort, and rolling resistance.8

This application can provide an exceptional accuracy of ± 2 % (total error, 0 – 50 °C) and a resolution of < 0.1 PSI.

Tire Pressure and Temperature Monitor

Dual-function pressure and temperature monitors can be mounted easily onto the tire valve of an eBike and deliver important insights to any smartphone device.

Merit Sensor technology allows for real-time monitoring of pressure, ensuring optimized battery life and rider comfort. Additionally, an early warning system alerts cyclists of slow punctures, reducing the risk of rim damage and maximizing rider safety.

Revolutionizing eBike Riding

The value of efficient and accessible modes of transportation and exercise has been emphasized by the rise of eBikes, which offer a favorable alternative to traditional bicycles. The expanding eBike market has brought with it a need for accurate tire pressure management, which is vital to ensuring rider safety and optimal riding conditions, particularly at fast riding speeds.

The CMS and RS Series of pressure sensors from Merit Sensor typify the recent improvements in cycling technology, catering to the diverse needs of riders. These technologies allow cyclists to enjoy smoother and safer rides with reduced risk of tire and rim damage, improved traction and enhanced comfort, ushering in an exciting new era for electric cycling.

For more information, contact a specialist at Merit Sensor today.

References and Further Reading

  1. Son, J., et al. (2022). Highly reliable triboelectric bicycle tire as self-powered bicycle safety light and pressure sensor. Nano Energy. doi.org/10.1016/j.nanoen.2021.106797
  2. Technavio. [Online] E-Bike Market Analysis APAC, Europe, North America, South America, Middle East and Africa – US, China, Japan, Germany, The Netherlands – Size and Forecast 2024-2028. Available at: https://www.technavio.com/report/e-bike-market-industry-analysis (Accessed on 07 February 2024).
  3. Rérat, P. (2021). The rise of the e-bike: Towards an extension of the practice of cycling? Mobilities. doi.org/10.1080/17450101.2021.1897236
  4. Electric Bike Owner. [Online] eBike Tire Pressure (Best PSI For Every Riding Condition). Available at: https://electricrideowner.com/ebike-tire-pressure/ (Accessed on 07 February 2024).
  5. Spokester. [Online] Bike Tire Pressure – Quick Guide to the right PSI for Bike Tires. Available at: https://spokester.com/blogs/news/bike-tire-pressure-quick-guide-to-the-right-psi-for-bike-tires (Accessed on 11 March 2024).
  6. Merit Sensor. Data Sheet: RS Series. Available at: https://meritsensor.com/assets/documents/pdf/RS-series.pdf
  7. Merit Sensor. Data Sheet: CMS Series. Available at: https://meritsensor.com/assets/documents/pdf/CMS-Series.pdf
  8. Backcountry. [Online] Quarq TyreWiz Air Pressure Sensor – Pair. Available at: https://www.backcountry.com/quarq-tyrewiz-air-pressure-sensor (Accessed on 07 February 2024).

This article is also published on  AZo Sensors.com

Understanding the Use and Function of MEMS Piezoresistive Pressure Sensors

In this interview, AZoSensors talks to Scott Sidwell, Engineering Manager at Merit Sensor Systems, about MEMS piezoresistive pressure sensors, silicon dies, and how these are all utilized across a range of industries.

Could you provide us with some background information on pressure sensors and their significance in various industries?

Pressure sensors are vital components that play a crucial role in various industries. The pressure sensor market is projected to see remarkable growth, as indicated by recent research, and it is expected to reach nearly 24.5 billion dollars by 2028.

They find applications in automotive, industrial automation and process control, consumer products like diving, e-bikes, and, importantly, in the medical field.

Pressure sensors work based on the principle of the force of a fluid divided by area. To put it into perspective, consider a syringe – a smaller one can generate more pressure than a larger one with the same force applied. Understanding this concept is crucial when dealing with pressure sensors.

Atmospheric pressure is a term we often hear. Could you explain what it is and its relevance in the context of pressure sensors?

Atmospheric pressure is essentially the weight of the air pressing down on us. As you ascend in an airplane or spacecraft, the air becomes less dense, with fewer molecules and less oxygen. It is important to consider atmospheric pressure when measuring the pressure in your application, because it will determine the type of pressure sensor needed.

Image Credit: Mi Sketch/Shutterstock.com

What other applications besides the automotive industry benefit from pressure sensors, and how are they used?

Pressure sensors find applications across a diverse spectrum of industries, expanding far beyond their traditional use in the automotive sector. One of the sectors where pressure sensors play a critical role is the diving industry. In this field, pressure sensors are employed to monitor the depth of divers underwater, enabling them to calculate ascent and descent times accurately. The hostile underwater environment necessitates reliable pressure measurements to ensure diver safety.

Pressure sensors have made their way into the consumer product market. For instance, in the realm of bicycles, especially the emerging category of e-bikes, pressure sensors are integrated into various components. These sensors may be utilized on bike shocks, tires, and other critical parts to enhance the overall performance and user experience.

What are the typical applications of piezoresistive pressure sensors, and how do they work?

Piezoresistive pressure sensors are a subtype of pressure sensors known for their versatility and use in various applications. Piezoresistive sensors function on a principle involving doped, semiconductor silicon crystal, which allows them to measure pressure more repeatably than other technologies.

To understand their typical applications, it is worth highlighting that piezoresistive pressure sensors are not constrained to a single field. They are used in an array of industries, including the medical sector. In medical procedures like angioplasty, where surgeons inflate balloons inside arteries, pressure sensors play a crucial role. In these procedures, the pressure sensor’s output helps the surgeon monitor the level of inflation inside the balloon, and assess the overall status of the procedure.

Can you explain what MEMS technology is and its advantages in the context of pressure sensors?

MEMS stands for Micro-Electrical-Mechanical Systems, and there are many different types of MEMS. The deposition, ion implantation, and diffusion steps are all fundamental to semiconductor manufacturing, as well as the photolithography and etching of MEMS pressure sensors. MEMS pressure sensors feature an elastic silicon diaphragm, which means they are free from hysteresis and creep.

This elasticity benefits the sensor because it allows it to undergo repeated pressure cycling without altering its properties. When things tend to creep or change, it is almost always a result of how they are packaged, not necessarily the silicon chip itself. Putting thousands of pressure sensors onto one wafer also significantly helps to reduce costs.

Merit Sensor has its wafer fab in Utah. There are many advantages to working with a vendor that has its wafer fab. When it comes to developing a new product, having your wafer fab is a huge advantage, as it allows you to control the supply chain. Keeping the design in-house is often considered the key to the successful development and launch of any product.

Can you give us a basic understanding of the MEMS pressure sensor?

The key design characteristic of a MEMS pressure sensor is the Wheatstone bridge diffused into the silicon diaphragm. The change in output from this bridge corresponds to a change in applied pressure.  When a customer needs a higher pressure range, the sensor requires a thicker diaphragm to handle the increased pressure. Conversely, for measuring low pressures, like inches of water or low pascals, a thin diaphragm suffices.

After the manufacturing process, the silicon is bonded to a piece of glass. The glass may have a hole to create a vent for various pressure applications, or it can be sealed without a hole. In the latter case, the glass and silicon are bonded together in a vacuum.

When there is no hole in the glass, it is known as an absolute sensor because the space between the silicon and glass represents zero pressure absolute.

There are two types of absolute sensors made from MEMS dies. The traditional type has no hole in the back glass, creating a sealed vacuum reference for absolute pressure. However, this design requires protection for the circuitry on the top side to prevent corrosion and shorts from humidity or moisture.

Alternatively, there is the absolute sensor with backside pressure. In this design, a piece of glass is added to the top of the silicon, creating a sealed vacuum reference on the top side and allowing for backside pressure on the MEMS element. This type is commonly used in automotive and high-temperature applications, as well as with liquids.

Cross Section of a MEMS Silicon Die with Top Glass

Can you tell us more about offset pressure and other factors like pressure non-linearity and hysteresis?

Offset pressure is the zero pressure measurement at room temperature. Pressure non-linearity measures how linear or nonlinear the sensor’s output is from zero pressure to full-scale pressure, and hysteresis reflects the difference between the initial zero and return zero, when pressure is applied and then relieved. The MEMS sensing element is designed to minimize these sources of error.

How do temperature-related factors, such as TCR and TCS, influence the behavior of pressure sensors?

It is possible to use the TCR, the Temperature Coefficient of Resistance, in conjunction with the pressure sensing to determine the temperature, because the TCR changes significantly with temperature. The Temperature Coefficient of Span/Sensitivity, or TCS, is important to take into account, especially in applications for wide operating temperature ranges. The TCS is negative, and when using the MEMS piezoresistive pressure sensor, the sensitivity or span decreases as the temperature rises.

Can you explain the importance of accuracy in pressure sensors and how it can be achieved?

Accuracy in pressure sensors is often measured as the total error band, which includes errors related to temperature and pressure. Achieving accuracy involves calibration, and fully compensated sensors with onboard ASICs simplify this process and provide higher accuracy. Accuracy is vital, especially in applications where precise measurements are critical.

How do stress and other external influences impact pressure sensors?

We take great pride in understanding and characterizing the sources of error that our customers can’t compensate for:  thermal hysteresis and long-term stability. The last thing our customers want is a part failure in their hands, which can occur due to long-term stability issues.

It’s important to keep in mind, that the MEMS sensing element is also a good stress sensor.  For example, a torque, or bending moment on the MEMS element will change the output of the Wheatstone bridge.  Stress can be induced during packaging and assembly processes, impacting sensor performance. Over time, any package-related stresses will relieve themselves and come back to equilibrium.  This stress-relief will manifest as a change in the offset of the sensor, in other words, offset drift and long-term stability. Careful handling and packaging are essential to maintain sensor stability.

Could you explain how MEMS dies are suitable for a wide range of applications, both specific and general, and what factors should customers consider when selecting a pressure sensor?

MEMS dies are common in pressure transducer or pressure transmitter applications where the MEMS die is on a header. The header gets welded into a stainless-steel housing with a stainless-steel diaphragm. Stainless steel is an excellent choice since it is very media-friendly, and most people are usually very familiar with stainless steel’s capabilities. This package is suitable for many industrial applications.

After welding the stainless-steel diaphragm and package together, there’s a back-filling of oil into this housing. A clean silicon oil surrounds the MEMS die, transmitting pressure between the stainless-steel diaphragm and the silicon diaphragm of the MEMS element.

In the HVAC industry, the MEMS die can be purchased separately or packaged into our LP series and placed on a control board. These control boards are found in large buildings, either atop the building near the air intake or in the building’s utility room, where heat exchangers and air airflow systems are located.

Another common application is in transportation. Pressure sensors are widely used in various types of automobiles. This area continues to grow as legislation drives the demand for higher efficiency and cleaner emissions.

To learn more, watch the full webinar below:

Understanding MEMS Piezoresistive Pressure Sensors: A Close Look at a Silicon Die from Merit Medical on Vimeo.

 

About the interviewee

Scott joined Merit Sensor in September of 2003. Before joining Merit Sensor, he worked in a variety of engineering roles with semiconductor companies, such as ON Semiconductor and Motorola. In his current role he works closely with customers to provide pressure-sensing solutions and technical support.

Scott received a chemical-engineering degree and MBA from Brigham Young University. He speaks Spanish and enjoys volunteering his time.

Choosing the Right Sensor for Harsh Environments in Fuel Cell Technology

Electric vehicles (EVs) have recently gained a huge amount of attention in the evolving transportation landscape.

According to the latest statistics, an estimated 14 million EVs are projected to be sold in 2023, reflecting a 35% year-on-year increase.1 Fuel cell EVs have also attracted attention from major players in the auto industry, including Toyota, Honda, and BMW.2,3,4

However, manufacturing fuel cell EVs poses significant challenges. Their reputation for being clean and eco-friendly, a remedy for our polluted past, is hard-earned.

This article will elaborate on the various internal components of a fuel cell EV, which must maintain different pressures to ensure optimal performance and safety. The pressure sensors, situated amidst these components, play a crucial role in monitoring the system.

 

 

 

 

 

Understanding Hydrogen Fuel Cells

Hydrogen fuel cells represent pioneering technology in sustainable energy. These cells harness the power of hydrogen, combining it with oxygen from the air to produce electricity, with only water vapor as the emission.

Currently, hydrogen’s use as an energy carrier is mainly for road vehicles. As of June 2021, over 40,000 fuel cell EVs were operational globally, with nearly 90% concentrated in four countries: Japan, Korea, China, and the United States.5

The utilization of hydrogen fuel cells is expected to grow, with CEM H2I leading the efforts to promote fuel cell technologies worldwide through collaboration with governments and partners.6

The Vital Role of Decompressing Hydrogen

In a typical hydrogen fuel cell EV, hydrogen is stored in a high-pressure container. However, because the fuel cell stack operates optimally at significantly lower pressure, a decompression procedure is necessary to bridge the gap between the high-pressure hydrogen tank and the fuel cell stack.

The decompression of hydrogen is crucial for the fuel cell to function effectively.7 Hydrogen, being the smallest particle, does not affect the absolute TRVC function, making radial sealing critical in design due to TRVC and plug geometry.

Significance of Heat Management Systems in EVs

Heat management, such as efficient cooling systems, plays a key role in the performance and lifespan of fuel cells.8

Making sure heat dissipates effectively is essential to keep critical parts like the battery and electronic systems within the required temperature limits. For batteries, this often means using a dedicated battery thermal management system (BTMS).

Keeping the right pressure in cooling systems specific to each EV is vital to prevent coolant leaks and potential damage to components.9

Importance of Pressure Sensors in Fuel Cell Technology

Precise pressure measurement is essential during energy generation and heat management. Accurate pressure sensors are necessary to monitor gas flow in pipelines and maintain proper coolant levels in the cooling system.

Sensors face challenges in harsh environments with corrosive substances, temperature changes, and high-pressure fluctuations. Thus, pressure sensors deployed in these settings must be designed to endure harsh conditions.

Introducing Merit Sensor’s TRVF-Series of Pressure Sensors

Merit Sensor, a top player in piezoresistive pressure sensors, crafted the TRVF-Series to meet industry needs. These sensors seamlessly integrate into fuel cell systems’ hydrogen supply and coolant circuits, ensuring top-notch stability.

Capable of handling temperatures from -40 °C to 150 °C, the TRVF-Series boasts exceptional durability thanks to its trio of materials – silicon, glass, and ceramic. These sensors are built to endure the harsh conditions within fuel cell environments.

The aforementioned materials also guarantee compatibility with various liquids, vapors, and gases, from fuel to water, ensuring longevity and reliability in challenging operational settings.

Covering a pressure range of 2–15 bar, the TRVF-Series offers precise measurements and accurate analog voltage output, enabling effective monitoring of gas and liquid pressures for optimized energy generation and improved heat management processes.10

The graph illustrates the stability results of the TRVF Series measured at 150 °C for 1300 hours.

Enhanced Reliability in Coolant Circuit Measurements

TRVF sensors have been designed to collect pressure measurements from its posterior surface. This is achieved by hermetically sealing the MEMS silicon die on top of a ceramic port, ensuring that the media only touches the desired wetted materials.

This functionality allows the sensor to consistently provide dependable readings within the coolant system, ensuring efficient coolant control and contributing to the overall effectiveness and performance of the fuel cell system.10

Measured Under Pressure: Serving Fuel Cell Technology with the TRVF-Series

The introduction of Merit Sensor’s TRVF-Series marks a significant advancement in fuel cell technology, addressing the crucial need for durable and accurate sensors capable of enduring the tough conditions within fuel cell systems.
With its sturdy build and dependable performance, the TRVF-Series is positioned to have a significant impact on driving the advancement of sustainable transportation and energy solutions, establishing a new standard of excellence in sensing technology for harsh fuel cell environments.

References and Further Reading

  1. IEA. Global EV Outlook 2023: Executive Summary. Available at: https://www.iea.org/reports/global-ev-outlook-2023/executive-summary (Accessed on 31 August 2023).
  2. Toyota. Toyota Launches the New Mirai. Available at: https://global.toyota/en/newsroom/toyota/33558148.html (Accessed on 31 August 2023).
  3. Honda. Honda To Begin U.S. Production of Fuel Cell Electric Vehicles in 2024. Available at: https://hondanews.com/en-US/releases/honda-to-begin-us-production-of-fuel cell-electric-vehicles-in-2024 (Accessed on 31 August 2023).
  4. BMW. BMW Group brings hydrogen cars to the road: BMW iX5 Hydrogen pilot fleet launches. Available at: https://www.press.bmwgroup.com/global/article/detail/T0408839EN/bmw-group-brings-hydrogen-cars-to-the-road:-bmw-ix5-hydrogen-pilot-fleet-launches?language=en (Accessed on 31 August 2023).
  5. IRENA. Hydrogen: Overview. Available at: https://www.irena.org/Energy-Transition/Technology/Hydrogen (Accessed on 31 August 2023).
  6. IEA. CEM Hydrogen Initiative. Available at: https://www.iea.org/programmes/cem-hydrogen-initiative (Accessed on 31 August 2023).
  7. Qian, JY., et al. (2019) Hydrogen decompression analysis by multi-stage Tesla valves for hydrogen fuel cell. International Journal of Hydrogen Energy. doi.org/10.1016/j.ijhydene.2019.03.235.
  8. Ahn, J-W., et al. (2008) Coolant controls of a PEM fuel cell system. Journal of Power Sources. doi.org/10.1016/j.jpowsour.2007.12.066
  9. Vehicle Service Pros. Hybrid and EV cooling system service. Available at: https://www.vehicleservicepros.com/service-repair/battery-and-electrical/article/21197978/hybrid-and-ev-cooling-system-service (Accessed on 31 August 2023).
  10. Merit Sensor. TRVF-Series: Available Now! Available at: https://meritsensor.com/products/trvf-series/ (Accessed on 31 August 2023).

View this article on AzoSensors.com

Creating Accurate Blood Pressure Sensors for Medical Equipment

In the medical industry, blood pressure monitoring is essential. Readings are used to evaluate general health and diagnose diseases. High blood pressure, otherwise known as hypertension, is a serious health risk and can also be indicative of other health problems.1

Thus, accurate and reliable blood pressure monitoring data is essential to ensure positive health outcomes for patients. Blood pressure monitoring is not only necessary for standard use but is critical when it comes to monitoring a patient’s condition online during critical surgical operations.

Extracorporeal membrane oxygenation (ECMO) is a crucial medical application that necessitates precise online monitoring. ECMO is used throughout certain surgical procedures where the patient’s heart and lung functions are compromised or for critically ill patients.

In an ECMO machine, blood is pumped outside the body for carbon dioxide removal and reoxygenation before returning it to the patient.2  ECMO is a feasible substitute for mechanical ventilation as it is able to reduce lung damage invoked by the positive pressure used in these methods.

Blood pressure monitoring equipment is essential when it comes to monitoring a patient’s condition and the ECMO machine itself.3 A typical healthy blood pressure level is traditionally lower than 120/80 mmHg. However, low blood pressure can be seen to fall as low as 90/60 mmHg.

In applications such as ECMO, blood pressure monitors with an extended reading range can be highly beneficial.

ECMO Machine featuring the BP Series extended range pressure sensor.

Merit Sensor Systems

Merit Sensor Systems is a globally renowned, industry-leading company with experience designing and producing highly accurate, piezoresistive technology-based pressure sensors. The company provides pressure sensors for blood pressure monitoring applications and a range of medical equipment.

The patient’s blood pressure measurements can be significantly impacted by the resting environment. One way in which data quality can be improved is by ambulatory blood pressure testing, in which portable devices are used to record blood pressure measurements throughout the day.4

MEMS piezoresistive sensors and assemblies, such as the BP Series, are ideally suited for portable blood pressure monitoring applications due to their compact sensor footprints.

Merit Sensor has a variety of sensors available for blood pressure monitoring applications. These include the BP Series, which operates in normal pressure ranges, and an extended range version suited for applications such as ECMO, where measurements must be taken over a wide range of -500 – 1000 mmHg.

The BP + T is designed for ultra-compact applications which additionally measure temperature ranges.

BP Series Sensors

Blood pressure monitoring sensors from Merit Sensor are ideal for invasive blood pressure monitoring applications and measurements, such as ECMO.

The standard BP Series configuration BP0001 covers the pressure range of -30 to 300 mmHg, providing a reliable signal that does not need any temperature correction (operating temperature 15-40 °C).

An ultra-compact sensor with an extremely robust design, the sensor is suitable for burst pressure readings up to 800 psi. Additionally, it is compliant with AAMI BP22 and RoHS standards.

Sensors provided by Merit Sensor Systems can be easily integrated into a range of medical devices, with standard solder pads providing connectivity. The standard seal diameter is 4.8 mm (BP0001), and a smaller seal diameter of 3.2 mm (BP0002), which minimizes the device’s overall footprint.

The small seal diameter in the sensors lowers the amount of blood in contact with the sensor, minimizing the risk of clotting or coagulation, which can decrease overall blood flow and cause problems with readings.

Alongside the sensor, a media-compatible medical dielectric gel is utilized for medical applications. The BP Series also includes an IMDS file for rapid and easy media compatibility verification, minimizing the time required to develop device prototypes.

       

BP Series 4.8mm Standard Seal Diameter               BP Series 3.2mm Small Seal Diameter

Extended Range

The BP Series Extended configuration provides measurements in the range of -500-1000 mmHg and can be used in applications such as ECMO. The system operates at a broader pressure range than the standard configuration.

The blood pressure monitoring sensors from Merit Sensor Systems are designed to handle high-pressure conditions and provide accurate readings over their entire operational range.

With an extended product shelf life of up to three years, the solutions offered by Merit Sensor Systems extend the lifespan of medical devices and ensure that pressure monitors remain functional, whether they are used as short-term or long-term solutions.

BP Series Extended Pressure Range Statistics

The graph below shows the over-pressure specifications limits for the BP Series Extended between -500 to 1000 mmHg. The test results are available in the Overpressure/Accuracy Report.

The BP + T sensor, which integrates pressure and temperature measurements in one device, is available as an upgrade option. The BP + T sensor is a direct in-flow measurement sensor that can monitor pressure and temperature at a single location.

The temperature reading is directly proportional to the Ohmic reading of the embedded thermistor, which is coated with a media-compatible substance. Two additional pads provide the temperature-measuring electrical connection (Kelvin-Point).

The BP + T sensor is also geometrically compatible with the BP0001 and overall BP Series configurations. The 3D-Model files are available for the verification of this integration capability.

Blood Pressure + Temperature Series

Applications

Merit Sensor’s devices are currently used in several novel lung support therapies and blood pressure sensors as part of lightweight and portable emergency response cardiopulmonary support systems.

The blood pressure sensors from Merit Sensor Systems are high quality and can handle the pressure peaks encountered in ECMO applications. Additionally, the sensors are cost-effective, even for disposable medical devices.

Contact Merit Sensor to find out which of its pressure sensors is the best option for your blood pressure monitoring application and how to benefit from its technical expertise and support.

Merit Sensor’s robust, reliable sensors offer clinical experts the highest quality assurance for medical applications.

References and Further Reading

  1. Elliott, W. J. (2003). The Economic Impact of Hypertension. The Journal of Clinical Hypertension, 5(3), 3–13. https://doi.org/10.1111/j.1524-6175.2003.02463.x
  2. Patel, A. R., Patel, A. R., Singh, S., Singh, S., & Khawaja, I. (2019). Applied Uses of Extracorporeal Membrane Oxygenation Therapy Different modes of ECMO therapy. Cureus, 11(7), e5163. https://doi.org/10.7759/cureus.5163
  3. Mossadegh, C. (2017). Monitoring the ECMO. In: Mossadegh, C., Combes, A. (eds) Nursing Care and ECMO. Springer, Cham. https://doi.org/10.1007/978-3-319-20101-6_5
  4. Turner, J. R., Viera, A. J., & Shimbo, D. (2015). Ambulatory Blood Pressure Monitoring in Clinical Practice: A Review. The American Journal of Medicine, 128(1), 14–20. https://doi.org/10.1016/j.amjmed.2014.07.021

Enhancing Pressure Transducer Performance with the S-Series Die

A pressure transducer is capable of accurately measuring pressure. It converts applied pressure into an electric signal and can be classified as an active or passive pressure measurement device.

Various designs of pressure transducers are available depending on whether absolute or relative pressure measurements are required.

Originally developed to measure minimal pressure changes, pressure transducers gained widespread commercial adoption in the 1960s and 70s by introducing thin film, silicon, and quartz-based devices. This made them a popular choice for measuring both low and high pressures.1

A pressure transducer comprises two main components: a pressure-sensitive device and a transduction element that converts device changes into an electrical signal.

Multiple designs exist for pressure transducers, utilizing methods such as strain gauge displacement or membrane movement. The design choice depends on the pressure ranges that need to be measured.

How Do Pressure Transducers Work?

Pressure transducers measure static or dynamic pressures, depending on whether the measured object is stationary or subject to an applied force.2

Piezoresistive strain gauges are commonly employed to measure static pressures.

These gauges are attached to a diaphragm that deforms under pressure, leading to a change in resistance which provides a measurable electric signal. This change in resistance is converted into a measurable voltage using circuit configuration.

In the case of high-compact pressure transducers, a microelectrochemical system (MEMS) device is used.

MEMS-based pressure transducers operate on similar principles as their larger counterparts, where deformation in the sensing medium generates an electrical signal. However, MEMS devices are much smaller and more responsive to even minor pressure changes.3

For remote applications like environmental monitoring in unmanned aerial vehicles (UAVs), MEMS sensors offer advantages such as low power consumption and lightweight construction.4

Merit Sensor S-Series

The S-Series, developed by Merit Sensor, is a remarkable sensor development and manufacturing achievement. These MEMS silicon pressure dies utilize a thin, flexible diaphragm as their sensing medium.

The diaphragm’s deflection, caused by pressure, alters the capacitance between two plates. This alteration can be converted into an electrical signal to provide pressure readings.

To deliver unparalleled performance, accuracy, and reliability in pressure sensing, the S-Series leverages Merit Sensor’s cutting-edge MeritUltra™ technology. These dies are designed to operate effectively across various pressures, from 5 to 300 psi, making them suitable for diverse applications.

By incorporating the MeritUltra™ technology, the S-Series dies offer an impressive temperature operating range of 40 °C to 150 °C without compromising performance.

The exceptional accuracy of the S-Series dies enables designers to achieve accuracies better than 0.1% of the full scale, making them suitable for even the most demanding high-precision applications. The S-Series is available with and without glass.

Merit Sensor's S Series MEMS Sensing Element JPG file

Unbeatable Accuracy and Reliability

High-quality calibration is a critical factor in pressure sensing. Precisely translating the movement of the diaphragm into meaningful pressure values necessitates a thorough characterization of the resistance change in response to applied pressure.

To ensure this, every S-Series die undergoes electrical testing at the wafer level when constructed at Merit Sensor Systems’ wafer fab in South Jordan, Utah, USA. The dies can be packaged by mounting them onto a circuit board and incorporating the necessary signal amplification electronics.

Extensive and rigorous testing and calibration procedures are employed, ensuring the dies are ready to provide reliable measurements immediately.

The S-Series dies’ robustness, reliability, and outstanding technical performance make them the preferred choice for many engineers when building pressure transducers.

Their compatibility with a wide range of environmental conditions, excellent sensitivity, and compact footprint make them ideal for numerous applications, including industrial, automotive, and medical sectors, where components must meet additional regulatory requirements regarding reliability and performance.

Whether clients require pressure transducers for aerospace, automotive, medical device engineering, or any other application, reaching out to Merit Sensor Systems will enable them to explore the benefits of incorporating its state-of-the-art pressure dies into their devices, leading to improved reliability and performance.

With the backing and expert support of the experienced professional teams at Merit Sensor, the client receives high measurement reliability, comprehensive pre-and post-sales support, and expert technical advice.

References and Further Reading

  1. Middelhoek, S. (2000). Celebration of the tenth transducers conference: The past, present and future of transducer research and development. Sensors and Actuators, 82, 2–23. https://doi.org/10.1016/S0924-4247(99)00395-7
  2. Bean, V. E. (1994). Dynamic Pressure Metrology. Metrologia, 30, 737. https://doi.org/10.1088/0026-1394/30/6/037
  3. Adams, T. M., & Layton, R. A. (2010). Introductory MEMS Fabrication and Applications. https://doi.org/10.1007/978-0-387-09511-0
  4. Jang, J. S., & Liccardo, D. (2006). Automation of Small UAVS using a low-cost MEMS Sensor and embedded computing platform. 2006 IEEE/AIAA 25TH Digital Avionics Systems Conference, 1–9. https://doi.org/10.1109/DASC.2006.313772

For more information, visit this article published on AZO Materials

Merit Sensor Logo Transparent Background

How Can Pressure Sensors Enhance Pneumatic Pressure Control in Robotics?

As part of increased automation and Industry 4.0 developments, robots had to become ‘smarter.’Regarding automation, smarter robots are those with more advanced sensors that have the ability to be integrated with data analysis and feedback systems.

One of the most common robot types in the industry are robotic arms. They have many uses, from lifting and moving objects to highly precise manufacturing and welding processes.

As an articulated robot, the robotic arm can be designed with a range of motion to suit its designated task, allowing it to carry out any required movements.

Robotic arms provide significant efficiency savings due to their ability to move much faster than their human equivalents. They also maintain high accuracy on numerous repetitive tasks that are involved in manufacturing processes. For some tasks, it is feasible to simply install and program a robot arm to conduct the desired function.

However, for alternative tasks where the robotic arm is used in conjunction with machine vision or more advanced automation, the robot is required to be able to react to and understand changes in the surrounding environment.

One way to help a robot understand the world around them, and allow them to react to tasks in a way that does not simply require pre-programmed and hard-coded parameters, is the utilization of pressure sensors.

Developments in transducer-based sensors for robots have enabled the creation of highly sophisticated articulated robot hands which are able to hold delicate objects.2 The sensor information is communicated to actuators to avoid the use of excessive force.

Pressure Transducer

Achieving increasingly complex motion and degrees of automation demands even more sensors to be utilized. A highly articulated robot hand or arm necessitates a full suite of sensors, with considerations such as the sensor size becoming critical for the application.

The precision and accuracy of the sensors also become progressively important when complex sensor networks provide feedback systems for the robot.

If any sensor within the network begins behaving poorly, the resulting robotic motion will be incorrect and could cause problematic motions for the articulation of the robot or accidental breakages.

In addition to the greater degrees of automation and the utilization of data in manufacturing processes, another aspect of Industry 4.0 development is a bigger emphasis on sustainability.

Mobile robot arms must keep power consumption to a minimum to extend the lifetime of operation between charges. The avoidance of large power draw on sensors also helps minimize the robot operation costs and decrease excess energy consumption.

Pressure Monitoring

One of the most generic tasks for a robotic arm is to hold and pick up objects, some of which may be breakable. A pneumatic actuator converts energy, usually from compressed air, into motion, and such actuators make up the basis of many mobile robots.

Exertion of the appropriate amount of force on an object involves careful control of the volume of compressed air supplied to the actuator. This is generally achieved by measuring the vacuum pressure within the evacuated region, and pressure sensors are the perfect system for this.

In addition to the initial force applied to pick up the object with the actuator, pressure sensors may be utilized to continually monitor the vacuum pressure during holding to guarantee that a constant level of force is maintained.

Pressure sensors in pneumatic actuators are required to have a rapid response time to sudden changes in pressure, especially for robots where the physical motions must be fast. Sensors also must be highly sensitive and have the ability to measure in the vacuum pressure range.

Merit Sensor Systems

The advantages of pressure sensors in robotic arms are evident when creating dynamically responding robots that are capable of a wider range of more sophisticated tasks. The challenge is finding the correct pressure sensor for the task.

Merit Sensor Systems is an expert when it comes to the development of MEMS piezoresistive pressure sensors and provides a variety of different compact, low-power draw sensors.

Merit Sensors has the CMS Series, which is a fully compensated pressure-sensor package for smart robotics.

Based on a piezoresistive pressure sensor with an ASIC to calibrate and compensate for thermal and non-linearity, the CMS Series are highly compact sensors created to provide highly stable and long-term pressure readings.

CMS Series

With a footprint of only 6.8 mm x 6.8 mm, the CMS Series makes integrating numerous sensors into pneumatic robot systems easy.

The digital I2C and SPI output options allow the CMS sensors to be easily integrated into smart feedback systems and make responsive robotics. Where multiple sensors are required for an application, Merit Sensor is also able to create other I2C addresses upon request.

The incorporation of the proprietary Sentium® technology makes the performance of the CMS Series unique. This technology helps these sensors accomplish their wide compensated temperature range (0 to 50 °C or -15 to 85 °C) with best-in-class stability.

The CMS Series are extremely diverse sensors with an extensive operating pressure range of 2 to 150 PSI, with burst pressures from 2 to 100 times the maximum operating pressure.

For pneumatic robotics, this range, combined with the high accuracy and stability, means it is possible to create robots capable of the most delicate lifting tasks as well as more heavy-duty operations.

Absolute and gauge options are also offered if required, in addition to autozero and output averaging functions, making the CMS Series even simpler to use and integrate into any system.

The electrical connections are SMD solder pads with a 1.27 mm standard spacing, and the CMS products are compatible with a 2.7 to 5.5 V supply voltage range. The devices may be run in a low-power mode to maximize energy efficiency.

The CMS products are all RoHS compliant, with the reliability and accuracy of these sensors underpinned by a piezoresistive Wheatstone bridge that is designed to anodically bond the glass to a chemically etched silicon diaphragm.

Contact Merit Sensor Systems today to discover how the CMS Series could further the performance and accuracy of your pneumatic robots and the overall efficiency of your systems.

References

  1. Sartal, A., Bellas, R., Mejías, A. M., & García-Collado, A. (2020). The sustainable manufacturing concept, evolution and opportunities within Industry 4.0: A literature review. Advances in Mechanical Engineering, 12(5). https://doi.org/10.1177/1687814020925232
  2. Girão, P. S., Ramos, P. M. P., Postolache, O., & Miguel Dias Pereira, J. (2013). Tactile sensors for robotic applications. Measurement: Journal of the International Measurement Confederation, 46(3), pp. 1257–1271. https://doi.org/10.1016/j.measurement.2012.11.015

For more information, visit this article on AZOSensors.com

Pressure Sensors and Their Use in Aquatic and Underwater Applications

Pressure sensors are essential safety and logistic equipment in a number of underwater applications. For scuba diving, a reliable depth gauge or diving watch is crucial to estimating diving depth and ensuring safe ascent and descent.

Historically, many dive watches and depth gauges have been analog designs. Digital pressure sensors have several advantages over analog sensors and can be easily interfaced with dive computers that combine information from multiple sensors.

A digital pressure sensor will consist of the sensing element; for pressure sensors, this is often a piezoresistive element and a transducer to convert the sensor response into a digital signal for processing. Digital sensors can be very compact, with no moving parts and can be used in harsh and corrosive environments, including in salt waters. Piezoresistive sensors are particularly well-suited for aquatic measurements as they have few restrictions on their operating depths.1

Common applications of such pressure sensors include sonar buoys, sometimes known as sonobuoys, tank and ocean depth measurements, dive watches and fishing.

MS Series inside Diving Watch

Merit Sensor Systems

Merit Sensor Systems is a leading expert in pressure sensors for a number of applications, including diving and freshwater work. Merit Sensor Systems offers several different sensing devices with incredibly small footprints and ultra-low power draw. The low power consumption is essential for many remote aquatic applications as devices must be battery operated and require a battery life of many hours.

For sonar buoys, deployable devices that use sonar signals to locate passing submarines and marine traffic or monitor tidal conditions, Merit Sensor Systems has developed pressure sensors that can replace the traditional wire/line technology. Normally, a buoy would be deployed with a spool of wire connecting the device to a float at the surface and the length of the wire is used to estimate the depth of the device. However, as the ocean is constantly moving, the wire displacement is often a bad measure of the depth due to lateral deflections of the device while it is in the water. A pressure sensor can instead provide more accurate depth measurements by measuring the local water pressure.

For sonar buoys, Merit Sensor Systems offers a range of suitable sensors, including the HTS 1510 Series, the TR series and, for more limited operating depths, the ultra low power MS series. All of these are highly compact, lightweight sensors that can be easily incorporated into a range of devices and provide many hours of continuous operation. The HTS series will also soon feature a Sleep mode so that the battery life can be further preserved.

All of the Merit Sensor Systems series are extremely media compatible with a range of water environments and conditions. The MS series is gel-filled for additional protection and its compact design footprint means it has been successfully used in dive watches. The MS series is an affordable option with excellent stability over an extensive temperature range and is also RoHS compliant.

HTS, TR, & MS Series in underwater applications.

Calculating Depth

Why do pressure sensors work so well for recovering depth information? As the density of water is constant in most environments, as is gravity, the underwater pressure is directly proportional to the submersion depth. With onboard electronics for the processing, a pressure sensor can rapidly convert these pressure readings into a measurement of submersion depth or even the local water level.

Diving computers can display and process a range of pressure information, from remaining gas levels in breathing tanks to diving depth. Some dive computers will use this to calculate the remaining safe time for a dive.

All of the Merit Sensor Systems pressure sensor series can be integrated as part of digital systems, but the HTS 1510 Series has the choice of providing digital or analog outputs.

Important for live depth calculations, all of the pressure sensors have 10 ms start up times in case devices need to be rebooted rapidly. Each pressure sensor is less than 2 g in mass, including any protective housing and mounts required, particularly for saltwater applications.

These pressure sensors are characterized by their potential to perform high accuracy measurements with only 0.5 % FS lifetime drifts, incredibly low pressure and temperature hysteresis. Whether you need a pressure sensor that can uphold the highest safety standards for manual diving, or a quick readout sensor for 24/7 online water tank monitoring, Merit Sensor Systems has something to offer.

The HTS 1510 Series, the TR series and the MS series each have different designs and housing to optimize them for particular tasks. The MS series is a surface-mounted, ceramic device. The fully-compensated TR series is a direct-media pressure monitor, designed to plug and play with existing devices. The HTS1510 series is a backside-pressure monitor which can be surface-mounted and integrated into existing control boards.

Contact Merit Sensor Systems today to find out how their state-of-the-art pressure sensors could be integrated into your underwater devices.

References:

  1. Büttgenbach, S., Constantinou, I., Dietzel, A., & Leester-Schädel, M. (2020). Case Studies in Micromechatronics. In Case Studies in Micromechatronics. https://doi.org/10.1007/978-3-662-61320-7

For more information visit this article featured on AZOSensors.com

Implementing Pressure Sensors into HVAC Systems

HVAC systems are vital when it comes to ensuring indoor air quality, health, and inhabitant comfort management.HVAC systems also have a central role in enhancing a building’s energy efficiency, as HVAC systems represent almost 50 % of the total energy consumption of buildings in the US and 20 % of all total energy consumption.2

Global temperatures and weather are likely to force an increased reliance on HVAC systems worldwide, meaning increased energy consumption which places utmost importance on finding ways to improve the efficiency of HVAC systems.3

One of the ways to achieve this is by using smart management systems for HVAC to do things like switch off unnecessary heating or ventilation in low or zero-occupancy buildings to ensure that no energy is wasted.4

The use of sensors lies at the core of smart HVAC systems. Sensors facilitate ‘machine vision’ for an automated system, delivering the information required to make intelligent decisions predicated on current demand and specified performance.

Sensors can also be incorporated into HVAC systems to enhance climate control and help send alerts when necessary maintenance to avoid needless work, which may also prevent system downtime.

Pressure Sensors in HVAC

Merit Sensor Systems is a global leader in the design and development of high-performance pressure sensors. Pressure sensors are one of the most important components in HVAC system technology for monitoring system performance, reviewing compressor conditions, and monitoring ducts to test the airflow through the ventilation systems.

Merit Sensor Systems has the services that help clients find the appropriate pressure sensors to make HVAC systems safer, more reliable, and cheaper to run.

HVAC systems are made of several components as a single system will need to have the capacity of cooling, warming, and providing air transport around the system and ventilation.

Continuous real-time pressure monitoring is suitable for checking if rooms or filters have pressure drops across them in order to check occupancy and performance. HVAC pressure sensors can also be installed to preserve pressure levels in key airways or those that necessitate positive pressures for safety reasons, including hospital laboratories.

LP Pressure Sensor

Compression

Conventional HVAC units typically contain a compressor that compresses a refrigerant vapor until it is transformed into a hot gas.

Pressure monitoring is crucial to check for leaks in this refrigerant application and the compressor performance, which is made possible with the TVC Series. Once the hot air is produced, it is cooled with ambient air that is subsequently heated by the transfer.

The gaseous refrigerant is pumped towards an evaporator as it cools, where it flows through a restrictor device to reduce the pressure of the refrigerant and evaporate it, cooling the air for recirculation.

There are various compressor designs, but the majority utilize the compression, evaporation, and cooling cycle to lower the air temperature.

TVC Pressure Sensor

Choosing Pressure Sensors

There are a number of different applications and a significant demand for pressure sensors in HVAC systems, but to be useful, pressure sensors need to have specific performance levels.

Some of the pressure changes in HVAC, including pressure drops across filters as a result of slight clogging, may be very small. Therefore, the pressure sensor needs to have a good limit of detection.

Small pressure changes and small overall pressures can also be observed in ventilation systems that require extremely sensitive pressure sensors. As smart HVAC systems are typically used to reduce energy consumption and waste, the pressure sensors that are installed in the system need to be completely reliable.

Errant and erroneous readings could lead to poor performance in the HVAC system or even damage components if maintenance warnings are not offered at the appropriate times.

The extremely compact LP Series pressure sensor is also part of Merit Sensor Systems’ portfolio and helps address all of these issues.

The LP Series pressure sensor has a low footprint and can be easily integrated into a circuit board design without resulting in extra bulk or weight to the finished product. The small footprint makes integration into nearly any application possible without the need for majorly redesigning components.

LP Pressure Sensor

LP and TVC Series Pressure Sensors

For HVAC applications, the LP Series pressure sensor has a detection capacity down to just 250 Pa with a resolution of more than 0.01 Pa. Initially designed with a sensitivity for the measurement of differential or gauge pressures, this pressure sensor requires just a 3.3- to 3.5 V supply to start supplying accurate and meaningful data.

The LP series pressure sensor contains two connectable (with tubing) pressure points. The sensor can then be connected via I2C or analog output for data monitoring in real-time as well as integration into smart building management systems.

The TVC Series is ideal for measuring refrigerant gas at higher pressures. It was developed to create a stable output, even at temperatures between –40 to 150 °C. The TVC is tasked with monitoring HVAC systems, water levels, water pressure and processes. It can also be used for air-conditioning and other refrigerant systems.

Inside the TVC Pressure Sensor

Inside the LP Pressure Sensor

Contact Merit Sensor Systems today to discover more and discover how the LP and TVC Series can revolutionize the efficiency of HVAC systems, with the sensitivity to determine exactly when the next maintenance cycle is due.

References and Further Reading

  1. Bearg, D. W. (2019). Indoor air quality and HVAC systems. Routledge. https://doi.org/10.1201/9780203751152
  2. Perez-Lombard, L., Ortiz, J., & Pout, C. (2008). A review on buildings energy consumption information ´. Energy and Buildings, 40, 394–398. https://doi.org/10.1016/j.enbuild.2007.03.007
  3. Wang, H., & Chen, Q. (2020). Impact of climate change heating and cooling energy use in buildings in the United States. Energy & Buildings, 82(2014), 428–436. https://doi.org/10.1016/j.enbuild.2014.07.034
  4. Wang, H., & Chen, Q. (2020). Impact of climate change heating and cooling energy use in buildings in the United States. Energy & Buildings, 82(2014), 428–436. https://doi.org/10.1016/j.enbuild.2014.07.034

For more information, visit this article on AZOSensors.com