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Ordering Information
State: dial size/scale range/size and location of connection/mounting options. Any optional extras, i.e.: max indicating pointer, polycarbonate window.

With out continued product development, items shown in this catalogue may change.

Selection and installation of pressure gauges

Forward
These notes have been written to help the selection and installation of pressure gauges, ensuring they give satisfactory service in the application they are intended for and also to ensure a high level of safety. If any other information is required refer to BS1780 : 1985.

Working Pressure
Pressure gauges can and will withstand the full scale pressure, but they should not continuously be used above 75% of the maximum graduation, or 65% of the maximum graduation for fluctuating pressures.

Material
The most used wetted parts in the construction of pressure gauges are brass/bronze and other copper based alloys. However numerous alternatives are available e.g. stainless steel etc. If the medium can solidify in the tube and alternative design of gauge should be used e.g. chemical seal or diaphragm gauge.

Gases and Steam
Gauges used on gas or steam with a maximum scale graduation of over 25 bar must have safety features comprising of a baffle plate between the sensing element and dial, a splinterproof windows, blow out release at the rear. All oxygen gauges must be of the safety pattern construction and should be supplied degreased and free from any oil contamination.

Pulsation - Vibration
Where possible gauges should be mounted away from vibration and connected by a flexible pipe. If this is impractical, liquid filled gauges can be supplied or viscous damped movements fitted. Also available for pulsation are protective devices such as snubbers / filled systems. If sudden shock and violent pulsation is likely the manufacturer should be consulted.

Connection or Jointing
When connecting gauges the joint must always be tightened using the hexagon or flats provided on the shank and NEVER by holding the case.

Valves and Cocks
Gauges should usually be fitted with some sort of cock or valve as it may be necessary to remove the instrument from service while the plant is in operation, for calibration or repair. Cocks and Valves should always be opened and closed slowly to avoid sudden changes of pressure in and out of the gauges.

Mounting
If a pressure gauge is used in a position other that vertical, allowances should be made during calibration.