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Protection against pressure spikes

If, for instance, a valve is closed very quickly, thus shutting off the pipe completely, then the pressure in the pipe falls suddenly to zero. This creates a shock wave that propagates at the speed of sound in the medium against the direction of flow. The shock wave is reflected at the container output, runs back to the valve input, is reflected again, and so on.
The superimposition of the shock wave and its reflections in both directions causes a sharp rise in pressure.

This increased pressure is known as a pressure spike. It can be many times higher than the operating pressure, and thus cause destruction of the sensor.

Pressure sensors can be damaged by pressure spikes.
Pressure spikes are often not noticed.


Extra code 591 - restrictor in the pressure channel

The restrictor is welded into the pressure channel.
The restrictor only lets the pressure pass through a restricted orifice, in a zigzag path. This reduces the energy of the pressure peaks arriving at the sensor membrane.


Application tips:

  • This problem does not arise with gases, only with liquid media, such as water, hydraulic fluids, beverages
  •  It is usually associated with valves and pumps


  • The pressure channel may become blocked by viscous media, calcification or deposits
  • The measuring signal response will become somewhat slower (milliseconds)