Flush Diaphragm

A flush diaphragm is a type of diaphragm which is completely open and exposed to the pressure media and level or slightly recessed to the surrounding surfaces when installed.

A pressure sensing device with a flush diaphragm is installed by either clamping to a flange ring around the outer diameter of the diaphragm or using a thread which has a large enough diameter to incorporate the diaphragm at the tip of the thread.

The materials used in the manufacture of flush diaphragms vary with the type of sensor technology and the intended liquid media to be measured. Dry cell sensing elements typically have thicker and more robust diaphragms which can be used with more abrasive media such as concrete and slurries. Oil-filled sensing elements with thin stainless steel isolation diaphragms can be used in hygienic conditions and on high temperature media.

There are certain media which cannot be used with conventional pressure sensors due to it being either too viscous or requiring a high level of cleanliness.

Flush diaphragms are used in specialised applications where the media is likely to clog enclosed process connections, an increase in volume will interfere with process performance or a high level of hygiene is required. The types of liquid media which require the use of flush diaphragms include sewage, paper pulp, adhesives, paint, food, drinks, pharmaceuticals, medicines, concrete, bitumen and slurries.