Merit Sensor Application Note AN105

To isolate the media to the wetted materials, i.e. glass, solder, ceramic, and silicon, you need to create a good seal. This will be best accomplished with an O-ring.

. The type of O-ring seal depends on the type of TR Series pressure sensor, specifically whether or not it has a ferrule/pressure port. This application note will discuss the face seal and radial seal. The images below with the O-rings in green show examples of both types of O-ring seal. There are many technical aspects, such as package stress, material compatibility, and O-ring geometry, that need to be evaluated when a seal is created with an O-ring. If you want to ensure that a good design is achieved during the first round of development, you must consider these aspects. This application note will help you know what should be considered.

There are many technical aspects, such as package stress, material compatibility, and O-ring geometry, that need to be evaluated when a seal is created with an O-ring. If you want to ensure that a good design is achieved during the first round of development, you must consider these aspects. This application note will help you know what should be considered.

Application Considerations

First and foremost, you should know the pressure, temperature, and media to which the pressure sensor and O-ring will be exposed.

Pressure

In regards to pressure, consider the following questions:

• What is the pressure range?
• Will pressure be positive at all times, negative at all times, or fluctuating between positive and negative pressure?
• Will pressure be constant or intermittent?

Temperature

In regards to temperature, consider the following questions:

• What is the storage-temperature range?
• What is the operating-temperature range?
• Is the operating temperature constant or fluctuating?