The following is a short synopsis of a new application note for the TR Series harsh media pressure sensor.
The TR Series Pressure Sensor is a fully calibrated, back side pressure sensor for use with any media that is also compatible with silicon, glass, ceramic and solder. The TR Series is designed to be used with an o-ring, creating a face seal to the back of the sensor.
When designing an o-ring face seal, several environmental factors much be taken into consideration:
- Temperature - What are the minimum/maximum temperatures for both operation AND storage? Does the temperature vary during operation or is it stable?
- Pressure range - Identify the minimum and maximum pressures. Are they positive, negative or both? Fluctuating or constant?
- Media - Identify what is in your media. What are the exposure conditions (temperature, pressure and concentration of chemicals in media). The backside is exposed to the harsh media while the front is exposed to another environment. This front side must be protected from harsh media.
Some o-ring features for users to decide include material and geometry options.
- Material - Different o-ring materials have different temperature handling abilities. A soft o-ring will provide a very compliant seal but many not seal well at high temperatures. A hard o-ring would seal well at high pressures but may induce high packaging stresses.
- Geometry options - O-ring size (both OD and cross-section) must ensure that media will not leak at the minimum and maximum pressure and operating temperatures.
The bottom line is to test with static and dynamic analyses in addition to customer verification, as each application is a unique combination of temperature, pressure and media.