Mercury Filling Melt Pressure Sensors

The Melt Pressure Transducer is an electronic device that converts energy from one form to another. In the case of an MPS pressure transducer, the process fluid exerts a pressure force on a thin, flexible metal diaphragm at the tip of the Melt Pressure Sensor. This highlights a small sensing device called the strain gauge. This strain gauge then converts the compressive strains into a low level millivolt (mV / V) signal that can be further conditioned to another type of signal.

 

 

 

For several reasons, the best Melt Pressure Sensor design is that the strain gauge is as close as possible to the process fluid. However, in an extrusion application the high temperature of the polymer melt jeopardizes its performance by taking the precision strain gauge beyond its measurement capabilities. To get the most out of the voltage gauge, the sensing element is placed remotely and isolated from high temperatures. Thus, the difficulty is transmitting the process pressure to the strain gauge without losing the integrity of the pressing force. This is accomplished using a transmission fluid that will best replicate the process pressure over a distance. Fluid must have physical properties to do the job.

 

 

 

A fluid-filled assembly consists of a diaphragm in contact with the high temperature treatment material, an upper sensing diaphragm dependent on the strain gauge, and a fluid-filled capillary tube connecting the two diaphragms. Filling material may have positive benefits and negative changes.