Today we have important news to share with you. After 34 years, Servoflo will discontinue its distribution business at the end of 2024. The global nature of our business has dictated that we seek a larger partner to serve our loyal customers who frequently design, source, and manufacture in all corners of the globe.

To that end, we will transition many customers to Angst+Pfister this year. Angst+Pfister (A+P) is an international distributor and manufacturer, headquartered in Zurich, Switzerland. They have a US division and lengthy experience with many of our factory partners in Europe. Our long-standing global relationship with A+P makes us confident you will be in good hands with them.

What does this mean for you, our cherished customer?

All current orders will be shipped as committed by Servoflo.  Expediting is possible as long as our inventory can meet an earlier date. All orders remain non-cancellable and non-returnable. If we have an excess inventory of parts you have previously ordered, we can accept orders anytime. In principle, A+P will begin accepting orders in May 2024. For the next several months, we will work closely with A+P to ensure a smooth transition of key personnel and business practices. Those with blanket orders, please be assured we will work closely with you to ensure you receive all your deliveries and we will put you in touch with the appropriate contacts for future orders. We will handhold every customer during this transition.

A+P will become the North American representative for Fujikura, Sensormate, Metallux, Consensic, HYB, and Siargo. While our two companies will not overlap in order taking, Servoflo will support A+P and our customers during this critical transition. A+P is a large, worldwide organization with in-house technical experts in various sensor technologies, applications, and architectures. Angst+Pfister can be contacted via their email box info.apus@angst-pfister.com for any sample, quote, order, or technical information request. For all other factories not mentioned, you may contact them directly.

Our factory partners have been fully supportive of this transition as they see the potential of A+P to support you:

"Fujikura has worked with Angst & Pfister in Europe for over 30 years. We are pleased to extend our relationship to North America with the new U.S. division of Angst & Pfister. We are confident our customers will be in capable hands." - Jason Peng, President of Fujikura America, Inc.

“Metallux is grateful for Servoflo’s past work in North America, and we are looking forward to continuing our growth and presence with our new Angst & Pfister partnership. We are confident in their technical knowledge and professional expertise.” – Massimo Romano - General Manager, Metallux SA

“Sensormate is excited to be part of the Angst & Pfister team in North America" - Leo Wu, President of Sensormate Enterprise Co., Ltd.

If you have any questions or concerns, contact us at info@servoflo.com or reply to this email. You may also call our office at 781-862-9572.

We are eternally grateful and humbled to have been in this business for 34 years. We have enjoyed this journey and have been privileged to learn from our customers who design and manufacture the best products in their markets.

Sincerely,

David Ezekiel, Owner
david@servoflo.com

About Angst+Pfister

Angst+Pfister is a leading supplier of technical components and comprehensive solution provider for a wide range of industries and has been ensuring business continuity and serving the world’s leading manufacturers for over 100 years. Their professional capabilities center on being an engineering-led solution provider with in-depth customer application knowledge; globally sourcing a wide range of high-quality standard and customized industrial components; and proactively serving original equipment manufacturers (OEMs) around the globe through multiple sales channels.

Angst+Pfister North America Inc. | 10391 Brecksville Rd. | Brecksville, OH 44141 | USA

Phone +1 (440) 375-5212

info.apus@angst-pfister.com

sensorsandpower.angst-pfister.com/en/

There are two types of pressure sensors used for negative pressure or vacuum pressure applications: gauge sensors and absolute pressure sensors. The reference pressure is the differentiating factor between these 2 types of sensors. The diagram below illustrates how the different methodologies work.

In applications that rely on the principle of a vacuum, it is important to effectively measure negative pressure (also known as vacuum pressure). There are two basic ways to do so:

• Measure the amount of pressure below local atmospheric pressure [typically 14.7 pounds/ square inch absolute (PSIA)]
• Measure how much pressure is above absolute zero vacuum (0 PSIA)

Both methods of measurement utilize the same scale and pressure point. However, these two measurements will yield differing results over time because one measurement's reference point is a fixed quantity (absolute zero vacuum), whereas the other relies upon a variable amount (atmospheric air pressure, which can fluctuate).

1. In the case of a gauge sensor, either a single port or dual port model can be used. In the case of a dual port gauge sensor, the "lower pressure" port measures the negative or vacuum pressure.
2. By accessing the "lower pressure" port, the user is mimicking applying positive pressure to the higher pressure port as in pressure range.
3. The advantage of using a gauge sensor is if the user wants to measure a vacuum smaller than the full vacuum range 14.7 psi, such as -3 psi, using a lower range focusing on the negative pressure range is more appropriate. This way, by using a smaller full-scale range pressure sensor, the user captures the full-range of the vacuum pressure measurements, thus obtaining more resolution and more design flexibility. For a single port gauge sensor, the single port is vented to the atmosphere.

For example, if a user is trying to measure the inhalation pressure in a respiratory application, the pressure range would be no more than 0.6 psi. If an absolute pressure sensor is used, only 4% of the pressure range would be used, hence wasting 96% of the sensor's calibrated range. By using a gauge sensor such as the AL4 Series, the user can capitalize on higher resolution and measure smaller negative pressure ranges.

Measuring Pressure Below Local Atmospheric Pressure Sources

Vacuum pressure is typically measured in terms of psi or pounds per square inch vacuum (PSIV). This measurement is generally relative to the surrounding atmospheric pressure. Vacuum pressure transducers can convert the inner negative pressure contained by an application into an electrical signal, and from there into a precise measurement.

At 0 PSIV—which is the same as typical atmospheric pressure, or 14.7 PSIA—the electrical output of a vacuum pressure transducer is 0 VDC. At full-scale, vacuum (14.7 PSIV or 0 PSIA), the output generally increased to about 5 VDC. A vacuum pressure transducer's output in volts increases proportionally to the increase in vacuum or negative pressure. On the other hand, an absolute pressure transducer emits increased positive voltage in proportion to decreasing vacuum.

Measuring How Much Pressure is Above Absolute Zero Vacuum Sources

The scale for absolute pressure begins at the high vacuum point of 0 PSIA. Unlike measurements that rely on atmospheric pressure as their main reference point, this methodology allows for more consistent readings.

An absolute pressure transducer features an electrical output of 0 VDC at 0 PSIA and increases to 5 VDC when it reaches full-scale pressure (14.7 PSIA). This output is expressed in positive voltage.

Pressure Sensors that Measure Negative Pressure

Vacuum pressure transducers and absolute pressure transducers measure the same thing using different points of reference. They are both crucial components for use in applications that require accurate and reliable negative pressure measurements for proper functionality and optimal performance.

When attempting to measure negative air pressure, it's important to use the proper equipment and to have that equipment calibrated to yield correct readings. Even small discrepancies between measurement and actual vacuum level could lead to performance issues.

Examples of classic applications where negative pressure measurements are needed include negative wound pressure therapy, breathing applications, pump control/performance monitoring, HVAC applications such as filter monitoring, and pressurized rooms such as cleanrooms and isolation rooms. One pressure sensor series which works well for these applications is the AP/AG Series from Fujikura.

To learn more, we have an e--book, How to Pick a Pressure Sensor.

At Servoflo, we are an industry-leading supplier of high-quality pressure sensors, environmental sensors, and micropumps  Our many years of expertise allow us to provide detailed and practical assistance for engineers designing new components. 

If you are in need of exceptionally precise and reliable sensors for negative pressure applications, then utilize our pressure sensor selector tool to tell us about your specific needs. Our team will then suggest specific parts for you to review. 

Various technologies are used to make pressure sensors. 2 of the most common include piezoresistive and capacitive pressure sensors. Both can be used for gauge, differential, or absolute pressure measurement. While piezoresistive is found in low-cost sensors, there are situations where a capacitive pressure sensor is better suited for the application.

In capacitive pressure sensors, the electrical capacitance changes with pressure. In simplified terms, this change in capacitance is measured and converted to a pressure measurement. This capacitive element technique creates a pressure sensor with key advantages, including:

Robustness: Capacitive pressure sensors can easily withstand high-proof pressures and overpressure.

Temperature performance: These sensors can operate over a wider temperature range than traditional piezoresistive pressure sensors. 

Power consumption: Capacitive pressure sensors use low power because no bias is required to operate the sensor.  This feature makes the sensors suitable for IIOT products where power use is critical. The sensors can be operated in extremely low power modes until activated when needed.

Accuracy: Low hysteresis, high repeatability and low sensitivity to temperature changes allow for highly accurate sensors. 

Long-term stability:  Minimal drift gives users superior long-term stability over other pressure sensors.

Newer packaging styles: Capacitive sensors have become much smaller compared to older generations which resembled a brick.

Because the production and calibration costs of capacitive sensors are higher, it is not expected to act as a replacement for lower-cost piezoresistive pressure sensors. Instead, these newer generation capacitive sensors open up opportunities for pressure measurement that cannot be done with piezoresistive pressure sensors. Some sample applications include: 

Production Equipment: Automated pumps and valves need to be monitored for pressure. A capacitive sensor has the safety to be exposed to harsher environments.

Industrial Filter Monitoring:  Differential pressure measurement is required to monitor filter clogging in industrial equipment. The capacitive sensor offers excellent overpressure tolerance (typically 100 times) and has a minimum in-line pressure drop requirement.

Powerless Pressure Monitoring System: Due to its nature, a capacitive pressure sensor does not require DC bias for its operation, minimizing power requirements, and allowing the user to set up remote wireless monitoring.  Wireless level tank monitoring can be done by creating a sensor network with data sent to the cloud. The excellent overpressure tolerance and high accuracy combined with the low power requirement make the capacitive pressure sensors a unique solution to solving difficult pressure measurement situations.

To learn more about the advantages of capacitive pressure sensors, check out these blog posts:

Learn the Differences: Rated Pressure, Overpressure, and Burst Pressure

If you are not sure what kind of sensor you might need, take advantage of our pressure sensor selector tool, and we will then provide you with specific options for your application!

Metallux of Switzerland is expanding its offering of electronic manufacturing services. These state-of-the-art manufacturing and engineering services help customers get to market quickly. Reliability and flexibility allows Metallux to engineer, prototype, and produce over 4.5 million products every year.

Services include:

To help better understand the capabilities available, here is a Q&A about these Metallux services.

What experience does Metallux have with power hybrids?

Metallux has long-term knowledge about chip & wire processes to interconnect bare chips to several types of different substrates by wedge & ball bonding. In the last two years, Metallux technicians attended several courses and learned relevant information about recent developments in the same processes for power dies.

What technologies and processes does Metallux have for the production of power hybrids and what investments are needed to produce them?

Metallux has many years of experience in screen printing on ceramic (alumina) and metal (steel) substrates, soldering, and various wire bonding techniques including standard hybrid technology (A12O3), thick film technology, die-bonding, standard wire bonding, and more. We have invested heavily in any additional processes and equipment necessary for power modules and expect to be able to produce samples in 2023. The same equipment can also be used for producing several tens of thousands of power devices.

What kind of information does Metallux need from the customer to provide samples?

Standard information such as application details, technical specifications, environmental situations, commercial (price target, quantities, desired production schedule), specific technology required, and reason for inquiry. For example, if there already is an existing supplier, what are the current stumbling blocks? In addition, we would also need a BOM, schematics, dimensions, operating temperature range, operating voltage, operating current, and power dissipation.

Learn more about hybrid circuit & power module manufacturing from Metallux.

In many applications and industries, it is not uncommon to come across the risk of excessive pressure, or overpressure, within the pneumatic or hydraulic network of equipment, especially in facilities with a high degree of automation. If this phenomenon is not controlled properly, it may cause permanent damage to equipment and production lines which is why pressure sensors are commonly used as some form of protection in several operations such as industrial, medical, bioprocessing, and pharmaceutical.

Nevertheless, pressure transducers are not always able to handle extreme levels of pressure. In order to survive extreme pressures, engineers and designers have defined pressure ratings that can describe the conditions a pressure component can withstand without affecting its operational performance. These are divided into:

• • • • • • rated pressure
          • overpressure
          • burst pressure

The maximum pressure that the manufacturer assigns as the desired pressure at which a device will function properly is normally outlined as rated pressure. An overpressure value is a condition where the pressure transducer can withstand excessive pressure without affecting performance or compromising subsequent measurements. Often overpressure is mistaken for burst pressure, which is defined as the maximum pressure that can be applied without physically damaging the body of the sensing component.

For example, if a pressure sensor has 2 bar rated pressure, 5x overpressure, and 10x burst pressure, this means that the sensor can measure pressures up to 2 bar, it can withstand overpressures up to 10 bar without being damaged, and if the pressure reaches 20 bar the sensor sealing will burst. From 10 to 20 bar, the sensor does not burst but it is damaged and will not operate as expected.

What can cause overpressure?

Different factors can trigger overpressure, including unintentionally increased heat, uplift, a faulty pressure regulator, process synchronization, or an amalgamation of all these factors.  These causes are common in industrial applications where there are solenoids, centrifugal pumps, regulators and valves.

How capacitive sensors can prevent catastrophic failures due to overpressure

Due to their design and measurement principle, MEMS capacitive pressure sensors can handle up to 100x overpressure, making them the only available sensor technology in the market that can withstand high overpressure.

The overpressure tolerance along with the excellent accuracy and total error band specification make capacitive sensors ideal for any application that uses pumps or valves, especially in automation equipment, where overpressure is frequently experienced. 

Before selecting a sensor, the maximum pressure value needed for the application should be taken into consideration. Understanding the advantages of each technology, the dynamics of their system, the limits of the sensor, and the various ways it can be applied are important to increase productivity and lower maintenance costs.

In the following figure, you can see an application example of the overpressure performance of a 10 bar absolute calibrated sensor from ES Systems. The sensor's maximum expected operating pressure (MEOP) is 10 bar. The sensor is measured at a reference pressure of 9.3 bar absolute and then pressurized at the following pressure steps as seen in the graph below.

As predicted, the sensor returns to nominal performance even with 100x overpressure is applied for a long period of time. 

Users of pressure and other environmental sensors enjoy a broad selection of models and manufacturers from which to choose. While detailed specifications of individual models are easy to come by, it often helps to understand more about the overall supplier. This blog post explains our approach to helping customers find the best part for their application.

Advantages of Servoflo

At Servoflo, we distribute a broad range of pressure sensors, mass flow sensors, humidity sensors and other types from leading manufacturers, including Fujikura, TE Connectivity, Merit Sensors, Metallux and more. Some of our suppliers have no other distribution partners here in North America, giving Servoflo customers unique access to a range of technologies. Our pressure sensor products meet measurement requirements across different price and performance points for pressure ranges from well below 2-inch water column (WC) to several thousand psi for applications in the medical, HVAC, and industrial industries. We also offer a variety of packaging options from board level to completely packaged transmitters. Similarly, our mass flow sensors, humidity sensors and other products go across the price-performance continuum to provide many choices for customers.

Individualized Customer Service

We focus on providing individual attention to meet the unique needs of our customers rather than locking them into a single family of standard products that feature unnecessary features at additional costs. At Servoflo, we proactively start with the question, "What problem are you trying to solve?". From this point, we collaboratively identify for our customers a range of potential solutions from the variety of factories we carry. We discuss with our customers various differences in performance.

Additionally, some of our suppliers provide customers with the opportunity to produce modified sensor designs that fit their specific applications in very low volumes with little to no price premium or expensive upfront investment. This level of customer service and customizing is not available from many large providers (both distributors & large manufacturers).

Greater Flexibility and Added Benefits

In many cases, pressure is not the only parameter requiring measurement. Other critical parameters that may require monitoring include mass flow, humidity, and temperature. We consider all of these factors and more when curating our product selection to offer solutions that meet a broader range of applications at competitive prices. In addition, we can provide benefits like inventory management, stocking, responsiveness, and easy access to technical support.

How We Work Compared to Other Distributors

Active versus passive selling:  Most distributors carry many manufacturers, pick some random parts to put into their stock and passively wait for the right customer to come along. At Servoflo, we communicate with customers directly to proactively match the customer with a range of potential solutions from the variety of factories we carry. We discuss with our customers various differences in performance, features and price to find the best match for their application. Other distributors make the customer dig around their web site, comparing data sheets on their own and often wait to get answers from experts if those experts even exist. Our active approach gives customers a part that meets their needs quickly and accurately. There is no guessing or trying a part that may or may not fit their needs. 

After a correct part has been selected, we can then provide logistical services to ensure that inventory is available for your manufacturing process. Our active approach creates a strong relationship with our customers to allow for adjustments for market changes, parts and product modification, shipping and much more.

Let us know how we can help you by giving us an old-fashioned telephone call at 781-862-9572 or use the contact us button. 

Our e-books are a popular way to learn how to pick a sensor!

This is a guest blog post reproduced with permission from ES Systems, a specialist in high quality pressure sensors for a variety of applications.

The majority of the pressure sensors currently installed in the field are based on MEMS technology and utilize either piezoresistive or capacitive measurement principle. In this article, we will be discussing their main differences and we will be highlighting the advantages of each.

How Piezoresistive Technology Works

The term piezoresistive is composed by the Greek word “piezo” (meaning squeeze or press) and resist. In piezoresistive sensors, four resistors are placed on a silicon diaphragm in order to measure the result of strain or physical pressure applied upon them. Any perceptible change in resistance is being converted, through a Wheatstone bridge circuit into an output voltage. The piezoresistive pressure measurement principle is one of the firstly developed in MEMS technology and it was developed many years before the capacitive one. As a result, it is most commonly used. Due to their widespread and low production cost, piezoresistive pressure sensors are widely used in consumer electronics and the automotive industry, as well as in household appliances.

Capacitive Technology Measurement Principle

Two parallel and electrically isolated conducting plates are needed to ensure that a capacitive pressure sensor operates efficiently. The bottom plate is fixed while the top one is sensitive to pressure changes. When pressure is applied, the top plate (or membrane) bends and a capacitance Δ is created. This variation in capacitance is then translated to an electrical signal where it can be read and conditioned by an ASIC or microcontroller.

Technology Comparison, Piezoresistive Vs. Capacitive

In comparison to piezoresistive sensors, capacitive pressure sensors offer many advantages. Even though they may require more complex signal conditioning circuits and calibration algorithms, they have higher accuracy and lower total error band. Moreover, capacitive pressure sensors have low power consumption since there is no DC current flowing through the sensor element due to its nature. Thus, very low power sensing systems, can be designed and implemented that require only a small bias to the circuit by an external reader, making them ideal for remote or implanted medical applications. The table below summarizes the pros and cons of the MEMS capacitive pressure sensors with respect to the piezoresistive ones.

MEMS capacitive pressure sensors also offer excellent long-term stability. This is a design attribute. As illustrated above, a typical MEMS capacitive pressure sensor element features two sense and two reference capacitors. The reference capacitors are not sensitive to pressure variations. The pressure calculation is performed using the following algorithm.

Long term stability is mainly affected by the aging of the sensing elements and therefore the drift in measurement accuracy over time.

Due to the layout of capacitive dies, the sense and reference capacitors are exposed to the same environment. That means that they are exposed to the same conditions and stimuli that cause aging to the sensors and therefore long-term drift. Since the sense and reference capacitors are exposed to the same conditions and are manufactured using the same materials and procedures, they also age with the same rate. Therefore, utilizing the pressure calculation algorithm and the layout of the MEMS die, the long-term drift effect is minimized and therefore an excellent long-term stability is achieved.

Last but not least, the major advantage of MEMS capacitive technology over piezoresistive is the overpressure tolerance (proof pressure and burst pressure). Due to their design, MEMS capacitive sensors can withstand up to 100x the rated pressure. This happens due to the fact that the sensor architecture consists of a fixed bottom plate and a suspended membrane which deforms with pressure. When overpressure is applied the deformation reaches the bottom membrane and inevitably stops without breaking. At the same time due to the distance traveled and the stresses exerted there are no plastic deformations. This translates into an unaffected sensor performance after the release of the overpressure.

Is capacitive technology ideal for overpressure?

As explained above, whenever overpressure is applied to automation equipment, conventional pressure sensors could get damaged. For that reason, sensors based on silicon capacitive process technology could be used. Understanding the advantages of capacitive technology and the various ways it can be applied to pressure sensors is important and could lead to increased productivity and lower maintenance costs. ES Systems has designed pressure sensors with capacitive technology that can offer high performance and precision along with great efficiency and reliability at a competitive cost.

Are capacitive sensors ideal for medical applications?

Medical applications can be enhanced by MEMS capacitive pressure sensors, as they could provide very high accuracy and long-term stability. More specifically, they are extremely tolerant of overpressure, making them suitable for use in applications where measurement safety is critical and sensor repair is not an option.

The cutting-edge MEMS capacitive technology can be applied in demanding environments regarding absolute, gauge, relative, or differential pressure measurements. For this reason, ES Systems offers three families of high-end capacitive pressure sensors for those needing superior accuracy. These families are:

• ESCP-MIS1, designed to sustain high measurement quality in harsh environments and media. Available now.
• ESCP-BMS1, ideal for industrial, medical and HVAC applications that require high accuracy and low total error band. Available early December 2020.

ESCP-MIS1	ESCP-BMS1

Want to chat more about pressure sensors? Get in touch to tell us what you need!

Servoflo is pleased to announce updated data sheets for the ME78X and ME79X ceramic pressure sensors from Metallux. These state-of-the-art ceramic pressure sensors have excellent accuracy and versatility for those users designing a pressure transducer or embedding a sensor in a pump, valve or other part of a pressure control system. A notable change is new designs for both the ME78X and ME79X will use an SSOP14 package rather than the previous DFN package.

The ME78X are a flush diaphragm, piezoresistive sensor with signal conditioning electronics embedded into the ceramic to provide a 0.5 to 4.5V ratiometric output or I2C output with pressure & temperature information. Calibration can be done in bar (0.5 to 600 bar) or psi (7.5 to 8500 psi). Furthermore, the sensor is available in a variety of configurations including absolute, gauge or sealed gauge. Accuracy choices include high accuracy, standard accuracy, no temperature compensation, or uncalibrated & uncompensated. The ME78X provides incredible versatility for users. The most updated information on the ME78X can be found here.

ME79X are monolithic piezoresistive ceramic pressure sensors. The Wheatstone bridge is screen-printed directly on one side of the ceramic cell by means of thick film technology and signal conditioning electronics generate 0.5 - 4.5V ratiometric output. Pressure and temperature calibration are done electronically with the on-board ASIC and can be performed in bar (3 to 400 bar) or in psi (50 to 5000 psi).

Electronics provide offset and span correction when the temperature changes. Aging detection is constantly performed. This new method guarantees good precision and long-term stability. The most recent data sheet includes a new mechanical configuration where springs are used for contacts. This innovative methods eliminates the need for soldering, increasing assembly speed, as well as improving ease of assembly resulting in lower overall costs. This mechanical configuration has been tested and validated in the automotive field for many years. Get the most recent information on the ME79X here.

You may notice that the ME78X is flush with a smooth side exposed to the pressure media and the ME79X are monolithic with a small indentation in the middle exposed to the media. Why choose one or the other? If a customer is making an absolute or sealed gauge sensor, then flush mount is ideal as they have a fixed reference. 

Both the ME78X and ME79X have excellent chemical resistance due to the AI₂O₃ ceramic, making them suitable for nearly all aggressive media.

Do you want to learn more about ceramic pressure sensors? Our e-book is a great place to start!

Data sheet links:

ME78X

ME79X

Users of pressure sensors enjoy a broad selection of models and manufacturers from which to choose. While detailed specifications of individual models are easy to come by, it often helps to understand more about the overall supplier. The following blog post compares board-level pressure sensors from Servoflo and other providers of pressure sensors.

Advantages of Servoflo

At Servoflo, we distribute a broad range of pressure sensors from leading manufacturers, including Fujikura, TE Connectivity, Merit Sensors, Silicon Microstructures and many more. Our sensor products meet the board-level pressure measurement requirements across different price and performance points for pressure ranges from 2-inch water column (WC) to several thousand psi for applications in the medical, HVAC, and industrial industries.

By partnering with us, our customers benefit from our:

Individualized Customer Service

We focus on providing individual attention to meet the unique needs of our customers rather than locking them into a single family of standard products that feature unnecessary features at additional costs. Additionally, some of our suppliers provide customers with the opportunity to produce modified sensor designs that fit their specific applications in very low volumes with little to no price premium or expensive upfront investment. This level of customer service and customizing is not available from many large providers (both distributors & large manufacturers).

Greater Flexibility and Added Benefits

In many cases, pressure is not the only parameter requiring measurement. Other critical parameters that may require monitoring include mass flow, humidity, and temperature. We consider all of these factors and more when curating our product selection to offer solutions that meet a broader range of applications at competitive prices. In addition, we can provide benefits like inventory management, stocking, responsiveness, and easy access to technical support like we do.

Sample Overview of Fujikura Sensors

Fujikura’s AL4 pressure sensor is a low-pressure sensor with digital output. It consists of a silicon piezoresistive pressure sensing chip combined with a signal conditioning integrated circuit. This sensor amplifies the low-level signal from the sensing chip, applies temperature compensation and calibration, and converts it to digital data in proportion to the applied pressure. Highlighted features of this sensor include: 

• Gauge: positive, negative, or bi-directional
• Differential: new feature now available!
• Pressure Ranges: 0–1 kPa (.145 psi) to 0–10 kPa (1.45 psi), depending on model
• Pressure Media: non-corrosive gases
• Supply Voltage (constant voltage): 5 +/-0.25 VDC, 3.3 VDC, or 3.0 VDC
• Accuracy: +/-1.5% FS
• Ports: dual barbed
• Size: 11.36 mm x 10.32 mm x 10.32 mm SMT package

Typical uses include battery-operated devices, medical equipment, industrial pneumatic devices, and various consumer devices.

Overview of Silicon Microstructures Sensors

MEMS pressure transducer technology and CMOS mixed-signal processing come together in the SM9333/SM9336 ultra-low differential pressure sensor. These sensors offer digital, fully conditioned, and multi-order pressure and temperature-compensated sensing. The highlighted features of this model include: 

• Pressure Range: 125 Pa to 250 Pa differential
• Digital Interface: 16 bit I2C
• Compensated Temperature Range: -20° C to 85° C
• Total Accuracy: +1% full-scale
• Insensitivity to mounting orientation
• Robust JEDEC SOIC (16 package with a dual vertical porting option)

Quality Sensors From Servoflo

The above highlighted products are 2 examples of our extensive product offering. We have many more product options that fit a wide variety of needs. High-quality products, individualized customer service, product design flexibility, and a variety of added benefits make Servoflo the better choice for board-level pressure sensors. Contact us to learn more about our board-level pressure sensor solutions or request a quote for our products from one of our experts.

In the medical industry, board level pressure sensors are commonly used in patient monitoring equipment. When used in treatment equipment, such as drug delivery systems or respiratory devices, they can act as monitors that trigger upon reaching a preset threshold and tell the control units to continue, change, or cease treatment.

Servoflo has worked with Fortune 500 major medical equipment manufacturers by providing pressure sensors and other environmental sensors in applications such as:

• Respirators and breath detection equipment
• O₂ concentrators and conservers
• Deep vein thrombosis treatment
• Infusion pumps
• Inflatable mattresses
• Blood pressure measurement

Pressure Sensors for Respirators and Breath Detection Equipment

Our pressure sensors for respirator and breath detection equipment generally monitor low-pressure conditions. They come in a variety of gauge or differential models, digital or analog outputs, and supply voltages. A good example of a pressure sensor is the AL4 Series.  The AL4 has various pressure ranges as low as 0-1 kPa (0.145 psi) with a digital output. What makes the AL4 special is that it has a high overpressure of 15 psi.

 Check out the industry page to review our wide selection of respirator and breath detection equipment pressure sensors.

Pressure Sensors and Oxygen Sensors for O₂ Concentrators and Conservers

Oxygen concentrators take in air, filter out impurities and other gases, and deliver pure oxygen to patients who require oxygen therapy, such as ones undergoing surgery or treatment for lung disease. Due to their critical function, these machines require highly accurate and consistent pressure sensors that can ensure precise and accurate control over treatment.

There are two applications for pressure sensors. The first is breath detection, similar to the respirator application described above. The second is to monitor the pressure in the oxygen line, which typically runs between 30-40 psi.

In this pressure range, there are many choices for sensors. Because there are so many options to choose from, Servoflo can help narrow down the choices for you by helping you choose a sensor based on your exact requirements. This way, you will not pick a sensor that is neither not accurate enough nor too accurate (& higher cost) for your application.

We also offer oxygen sensors that monitor the oxygen percentages delivered to the patient. Check out the product page to more about our selection of pressure sensors and oxygen sensors for O2 concentrators and conservers.

Pressure Sensors for Deep Vein Thrombosis Treatment

Deep vein thrombosis, also referred to as DVT, occurs when a blood clot develops in a vein located deep within the body. Pneumatic compression devices can prevent DVT or facilitate treatment by promoting circulation and lymphatic drainage. Typical pressures run about 5 psi.

Our pressure sensors for deep vein thrombosis treatment equipment feature a variety of specifications, including in regard to outputs, pressure ranges, and accuracy levels, to ensure that individualized DVT treatments occur as expected. Check out the product page to more about our selection of deep vein thrombosis pressure sensors.

Infusion Pumps

Medical professionals use infusion pumps in hospitals, medical offices, nursing homes, and private residences to deliver vital fluids, such as nutrients, medication, or saline, to a patient’s body. These machines need accurate pressure sensors to maintain a controlled flow. The pressure sensors are used to monitor the pump’s backpressure to ensure that the pump is working correctly.

Our infusion pump pressure sensors meet a variety of pressure range demands. The sensors are temperature-compensated and have chips that provide data for smart infusion pump equipment. Check out the product page to more about our selection of infusion pump pressure sensors.

Inflatable Mattresses

Medical inflatable mattresses have more specialized functions than traditional inflatable mattresses. They enhance circulation to prevent soreness, stress, or decreased blood flow while providing support and comfort. Patients use medical inflatable mattresses during extended periods of bed rest to reduce the risk of skin shearing and pressure sores. Different varieties of these mattresses need pressure sensors, typically 3 psi and below, to prevent air loss or replenish lost air.

Our line of sensors facilitates the maintenance of stable, comfortable pressure levels and monitor the mattress’s fluid conditions to protect the patient. Check out the product page to more about our selection of inflatable mattress pressure sensors.

Blood Pressure Measurement

Blood pressure measurement is one of the main applications of medical pressure sensors. The sensors allow for non-invasive measurement of blood pressure, providing insight into a patient’s condition during routine appointments, extended hospital stays, and medical treatments. The pressure sensors are used in electronic blood pressure equipment (not the traditional mechanical units used in a doctor’s office).

Our pressure sensors come in a variety of power requirement, display, pressure threshold, and size options. We have pressure sensors designed specifically for blood pressure instrumentation. The models include the AP3/AG3NIBP. This is a standard sensor specially calibrated  for +/- 3 mm of mercury. The datasheet can be accessed here.

Contact Servoflo for Your Medical Pressure Sensor Needs Today

Pressure sensors serve an important role in many medical applications. As such, it’s crucial to choose high-quality sensors that exactly suit the nature and requirements of the application. To learn more about our pressure sensors, contact us today. For assistance choosing one for your application, download our eBook or request a quote.