DIAPHRAGM (Continued from part-1, click here to go to part-1):
- It uses the deflection of a flexible membrane that separates regions of different pressure.
- The amount of deflection is repeatable for known pressures so the pressure can be determined by using calibration.
- The deformation of a thin diaphragm is dependent on the difference in pressure between its two
- The reference face can be open to atmosphere to measure gauge pressure, open to a second port to measure differential pressure, or can be sealed against a vacuum or other fixed reference pressure to measure absolute pressure. The deformation can be measured using mechanical,optical or capacitive techniques. Ceramic and metallic diaphragms are used.
- Range: (-) 10000 to (+) 10000 mmWC
- Small size & moderate cost
- Adaptability to slurry services & absolute & diff. press.
- High over range characteristics
- Limited to low pressure
- Difficult to repair
- Less vibration & shock resistance
- A capsule is formed by joining the peripheries of two diaphragms through soldering or welding.
- Used in some absolute pressure gages.
Range of Elastic-Element Pressure Gages:
Diaphragm seals: These are designed to isolate the sensing element of pressure gauges from process fluids.
Gauge Saver: Gauge Savers also known as over pressure protectors are applicable where pressures exceed the maximum pressure rating of the pressure gauge.
Pulsation dampener: Dampeners considerably reduce the pulsations and makes the gauge reading easier and also improves the life of the gauge.
Syphon : This connected between the pressure gauge & process in applications, where high temperature like steam, vapours or fluids are present. It acts as a cooling coil and protects the gauge from high temperature and also helps in dissipating heat.
PRECAUTIONS: WHEN FIRST INSTALLED THE SYPHON SHOULD BE FILLED WITH WATER OR ANY OTHER SUITABLE SEPERATING LIQUID.
- U TYPE – FOR HORIZONTAL PRESSURE TAPPING
- Q TYPE – FOR VERTICAL PRESSURE TAPPING
Needle valve: The large round handle offers maximum ease and precise control to throttle the pressure to the gauge.
Block & Bleed Valve: Equipment Isolation with automatic pressure bleed for safety
- These are fluid distribution devices.
- These are used in conjunction with pressure gauges, differential pressure gauges & differential pressure transmitter.
- They combine instrument isolation & equalizing in one block.
- The manifolds are available in 2way, 3 way & 5 way types with remote & direct mounting styles
Gauge cock: It is used in conjunction with siphon as an isolation valve. It is not recommended for pressure over 100 psi.
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