1199 Remote Mount Diaphragm Seal Systems

Differential pressure transmitter assembly with remote mount diaphragm seal system consists of a differential transmitter, one or two remote diaphragm seal systems and one fill fluid. In service, the thin and elastic diaphragm, which is connected to the transmitter by capillaries or flange, together with the fill fluid, separates the sensor elements from the process.

When applying process pressure, the diaphragm of the fill fluid system is deformed and transfers the pressure to the diaphragm of the transmitter through capillaries. The transferred pressure results in deformation to the sensing diaphragm in the sensor module, which is proportional to the process pressure and is converted to appropriate current, voltage or digital HART output signal.

While expanding the applications of the transmitter, the remote seal system also affects the overall performance of the instrument, such as amplified temperature effects, slowed response, etc. To minimize the impacts and meet the requirements for process control, please note the following precautions.

• Selecting appropriate models based on the flow, for example the pressure, temperature or fill fluid type
• The two remote seal systems of a DP transmitter shall be aligned to each other.
• While ensuring normal operation, the capillaries shall be kept as short as possible to reduce temperature effects and cut short the response time.
• The thickness and diameter of diaphragm affect the temperature but selecting thin and large diameter diaphragm could reduce the effects.
• Note As the limit of remote pressure is associated with fill fluid density and the height difference of the pressure, the effects of the transmitter-to-remote seal system location shall be calculated particularly in vacuum service.

Remote Diaphragm Seal System Types
	FFW	Flush Flanged Seal System
	EFW	Extended Flanged (Plug-in) Seal system
	RTW	Remote Threaded Seal system
	RFW	Remote Flange Seal system
	SCW	Hygienic Tri-clover Tri Clamp Seal