Pressure gauge is still one of the most common methods […]
Pressure gauge is still one of the most common methods of measuring pressure as so far. It can be used for monitoring liquids and gas pressure in many different applications.
Process media generally flow through a piping system at relatively high pressure, and gauges rated to that pressure are often installed to monitor the process. A problem can occur when pumps are switched on or off, or valves are opened or closed, and the media surges through the pipe and causes a spike on the pressure gauge, which can damage the instrument. Overpressure protectors such as snubbers or valves can be applied to address conditions where spikes are most likely to occur.
Gauge accuracy can also be affected by temperature changes. The change in the elasticity or spring rate of the Bourdon tube element with temperature. While it is difficult to circumvent the influence of ambient temperature, the influence of process temperature can be addressed.
The gauge's Bourdon tube can be weakened by corrosive chemicals in media or environment. This may occur as a pinhole leakage or early fatigue failure because of stress cracking. It is critical to be aware of the chemical compatibility of the media with a gauge’s case and construction materials. Diaphragm seals can also be employed to protect the gauge from the media.
Vibration also can have a significant effect on gauge performance. Vibration due to pumps, motors and other rotating equipment can cause excess wear and possible premature failure of the internal working parts of a pressure gauge, which include the Bourdon tube and the movement or gear mechanism. Vibration also causes difficulty in accurate reading of the gauge because of pointer oscillation. Liquid-filled gauges address not only pointer oscillation, but also serve to protect and lubricate the internal geared movement.
Error Process Connections
Pressure gauges are available in a variety of process connections, sizes and case mounting styles. The proper process connection must be specified depending on system requirements and application.