Sensing pressure in a slurry line or high viscous product line is always a problem. The gauge will get plugged and will simply get stuck at some reading. Plant engineers are familiar with this problem (Fig 1).
Solution to this is not easy; commercially available Diaphragm Gauges are suitable for clean liquids which are corrosive. For slurry / viscous liquids only a ring gauge is suitable. This is not readily available in many parts of the world.
Solution lies in making the pressure sensing part of the gauge immune to slurry or liquids that tend to solidify.
A discarded diaphragm valve can be converted into a reliable pressure / vacuum gauge. The accompanying drawing shows the steps needed to convert it to a reliable pressure gauge (Fig 2).
Instead elastomer, a flexible metallic diaphragm can also be used- like the one used by conventional diaphragm gauge manufacturers.
This can be a project for engineering college student. The product can be offered as a gift to a plant where thick liquids/slurries etc are being monitored.
For a fraction of an imported Ring Gauge cost – you can have your own gauge made from discarded Diaphragm Valve body!