Pressure Measurement Solutions in High Temperature Applications
Many industries rely heavily on high temperature pressure sensors to ensure safety and efficiency in challenging environments. Correct temperature ratings on pressure measuring equipment is critical to maintaining the functional longevity of sensors, reliability and accuracy of pressure readings, and overall safety in hazardous applications.
Some of the most demanding markets and applications can include:
- Oil and Gas - in drilling and production processes where high temperatures and pressures are common. Sensors ensure accurate pressure measurements for safe and efficient extraction operations.
- Power Generation - in monitoring steam pressure and temperature in power plants, including nuclear and geothermal facilities for efficient energy production.
- Automotive - in engine performance monitoring to optimise fuel efficiency and emissions control. Sensors provide important data for managing high temperature conditions in engines.
Using sensors and transmitters outside of manufacturing recommended operating conditions (both process and ambient temperatures) can lead to inaccurate readings, cumulative long term drift, increased thermal error, unstable response times, fatigue life and more. High temperature measuring solutions are at the core of what we do, with several simple but effective solutions available to help combat extreme temperature scenarios.
This blog will explore the challenges of high-temperature environments, specifically focusing on thermal stress, corrosion and mechanical fatigue, which call for the use of advanced materials and technologies. We will discuss the selection of appropriate materials for pressure sensors, highlighting the importance of thermal stability, corrosion resistance and mechanical strength. Our recommendations for top pressure sensors suitable for high temperatures are provided.
Challenges of High Temperature Environments
Some of the most common challenges of high temperature environments can include thermal stress, corrosion and oxidation, mechanical fatigue and creep.
Thermal Stress
- High temperatures can cause materials to expand, leading to thermal stress. This can result in deformation or failure of components.
- Thermal cycling, or repeated heating and cooling can exacerbate stress and lead to potential cracking or warping of materials.
- Typical industries affected include aerospace, automotive and power generation, where materials are routinely exposed to high thermal loads.
Corrosion and Oxidation
- High temperatures accelerate corrosion and oxidation processes, degrading materials and reducing their lifespan.
- Corrosive environments, such as those found in oil and gas industries, can lead to severe material failures through mechanisms like sour and sweet corrosion.
- Chemical processing and marine industries also face significant challenges due to high-temperature corrosion.
Mechanical Fatigue and Creep
- Mechanical fatigue occurs when materials are subjected to cyclic physical stresses, leading to progressive and localised structural damage.
- Creep is the tendency of a material to deform permanently under constant stress at high temperatures.
- Nuclear power plants and aerospace industries often encounter fatigue and creep issues due to prolonged exposure to high temperatures and stresses.
We can help to combat all of these challenges through consultation and safe selection of pressure sensors.
Selecting the Right Materials
Selecting the right construction materials for media wetted parts is essential when specifying pressure sensors in demanding applications.
To cover a live example, we have two very similar pressure sensor models with one critical difference - the wetted construction material.
In a live scenario, the 3100 series was being used in a unique Hydrogen Fuel Cell Technology application to measure pressures of 20 - 25 BAR. Due to the location of the sensor installation, it was also exposed to high temperatures of around +100°C. Because of the 17-4PH stainless steel wetted parts, used in conjunction with this specific media and temperature (plus other environmental factors), the sensor was prone to giving inaccurate readings due to internal pitting.
Once Boiswood were called in to provide technical support and consultation, we identified that the 3500 series with 316L stainless steel wetted parts would be a better solution for the application. Following a successful trial with the new unit, all of the unstable readings went away and the sensor continues to operate as expected to this day. Construction materials are key to delivering maximum performance.
Consequences of Using Standard Pressure Sensor Materials
- Standard materials or certain grades of stainless steel may not withstand high temperatures, leading to sensor degradation or failure.
- Exposure to extreme temperatures can cause significant errors in pressure readings or complete operational failure.
- In critical applications, such as petrochemical or aerospace industries, failure of a pressure sensor can lead to costly downtime or safety hazards.
Characteristics of Suitable Materials for High-Temperature Environments
- High Thermal Stability - materials should maintain structural integrity and performance at elevated temperatures.
- Corrosion and Oxidation Resistance - essential for longevity in harsh environments where chemical exposure is common.
- Mechanical Strength - ability to withstand thermal stress, mechanical fatigue and creep over prolonged periods.
- Thermal Conductivity - efficient heat dissipation to prevent overheating of sensor components.
Recommended Materials for High-Temperature Pressure Sensors
- Inconel and Other High-Performance Alloys (such as Monel, Super Duplex or Hastelloy) for body construction materials. These are typically known for high-temperature strength and resistance to oxidation and corrosion. They are commonly used in aerospace, power generation and chemical processing industries.
- Ceramic and Sapphire for sensing elements. They have higher melting points and excellent thermal stability for extreme temperature applications. They can often be found in optical sensors for high-temperature environments.
Recommended Pressure Sensors for High Temperatures
We pride ourselves on a high-quality, durable and reliable product range; backed by a competitive pricing structure, ever-growing stock portfolio for quick delivery times and international shipping.
Below we will focus on 3 top-performing sensor solutions suitable for high-temperature environments, offering durability, reliability and safety.
- Diaphragm Seal Systems - allow for many standard sensor configurations to be utilised by separating them from direct contact with the process media. Irrespective of the sensors operating temperature range, diaphragm seal systems can be used to extend the temperature rating as a complete assembly. Whilst diaphragm seal systems are often found in pharmaceutical, biotechnology and food & beverage applications, they can also be used to accommodate for high operating temperature requirements in oil & gas, chemical/petrochemical and automotive industries.
As an example setup, the S-20 general pressure sensor has an optional standalone temperature rating of -40°C to +200°C (maximum range). By coupling this sensor into a simple diaphragm seal assembly (shown in figure below), the minimum temperature can be extended down to -90°C and the maximum temperature up to +450°C.
Diaphragm seal systems can be found in threaded, welded and hygienic designs depending on the application requirements.
- Utilising Accessories - as part of our instrument hookups range, additional accessories can also be utilised on standard pressure sensors to help combat higher temperature requirements. Accessories such as cooling elements and syphons can help to extend higher temperature limits on typical pressure sensors.
As an example setup, the 3100 series OEM pressure sensor has a standard temperature range of -40°C to +125°C. By utilising in conjunction with a 910.32 cooling element, the upper temperature limit can be extended up to +200°C (on the 5 fin version).
Additionally, compact, U-form and trumpet style syphons can also be used to help dissipate any unexpected high temperature fluctuations.
- Exotic Alloys - such as Elgiloy or Gold-Plated sensing elements for particularly challenging media. Specifically in the case of Hydrogen applications, sensors can experience many severe combinations of extreme pressure and temperatures.
The IS-3 ATEX approved pressure sensor is the perfect solution for Hydrogen applications and can be manufactured with an Elgiloy sensing element to ensure longevity when exposed to this media.
The PSD-4 electronic pressure switch can be manufactured with a gold-plated sensing element to help with the same.
Typically as a rule of thumb, we would utilise Elgiloy sensing elements for higher pressures (in excess of 25 BAR) and Gold-plated elements for anything less than this.
Conclusion
The importance of selecting the right materials and suitable pressure sensors for high-temperature environments is paramount for operational reliability and safety.
We are always here to provide personalised consultations for specific application requirements and are happy to accommodate with customised solutions. These solutions can be tailored to accommodate unique ranges or conditions for optimal performance.
Boiswood have 35+ years of industry experience, which enables us to address varied and complex demands in a diverse range of niche industries. In the ever-growing world of new applications and the UK at the forefront for R&D applications, we are here to help and open to discussing your requirements.
Please click here to submit a request for consultation and feel free to download our free general overview brochure below:
