Selecting a Pressure Gauge
Selecting the appropriate pressure gauge for a particular application can sometimes be a challenge. These guidelines will help you select a pressure gauge that is most suitable.
Consider the Environment & Application
Is the medium corrosive?
Does the medium contain solids?
Is a diaphragm seal required?
What material of tube & socket is appropriate? Brass, 316 Stainless steel, Monel, etc.?
Will there be heavy pulsation or vibration in the application?
Will the gauge be used inside or outside?
Are there any temperature extremes to take into account?
Do you need a big dial to be able to read from a distance, or a small dial to fit in tight spaces?
Is your pressure measurement for a general purpose application or a critical piece of equipment where accuracy and reliability is of utmost interest?
Will the pressure gauge be direct stem mounted, panel mounted, flush mounted or remote mounted?
Select a pressure range that is approximately twice the normal operating pressure of the media. The maximum operating pressure should not exceed 75% of the full scale range. If the gauge is liquid filled, check to see if the temperature ranges fall within acceptable limits.
Environment & Application
As the Bourdon tube is in direct contact with the medium being measured, the characteristics of the medium must be considered. Consider using a diaphragm seal if the process medium is corrosive, will leave a deposit or clog the Bourdon tube, or if the medium will solidify in the Bourdon tube.
Choosing the material of the pressure gauge is also important. If the medium is corrosive, stainless steel internals and casing should be chosen over brass. Brass is more suitable for general applications. The effects of moisture and weather conditions may also be harmful to the gauge and should be considered when selecting a gauge.
For applications that produce harmful pulsation, vibration or pressure spikes, the appropriate gauge or option should be chosen. For example, liquid filling a gauge or opting for a StabiliZR™ Gauge will minimize any ill effects of vibration and provide an easier pressure reading.
Guanshan manufactures a range of dial sizes, from 1¡± to 10¡±.
Guanshan offers bottom and back (centre and lower) connections on our gauges. The standard thread is G, however, other options are available such as BSP, SAE and many other special fittings. The most common connection sizes are 1/4" and 1/2". Please contact Guanshan for all available connections.
The degree of accuracy required should be determined to ensure that the proper gauge is used. Guanshan utilizes the ANSI/ASME standards for accuracy grading. We offer pressure gauges with accuracy from +/- 0.4% (ANSI/ASME Grade 3A) to +/- 3-2-3% (ANSI/ASME Grade B). Generally, the more critical the application, the higher the accuracy required.
Guanshan pressure gauges can be mounted in a variety of ways. For direct stem mount, we offer bottom, centre back, lower back and in-line connections. Consider purchasing a back flange for panel mounts, or a front flange if you need the gauge to be flush mounted. U-clamps are available as an alternative to flush mounting a gauge, or if you are unable to use a front flange. Also bear in mind that if a piece of equipment produces heavy vibration making pressure reading difficult, a gauge may be mounted remotely.
Range Pressure Range
It is important to select a pressure range that is approximately twice the normal operating pressure of the media. The maximum operating pressure should not exceed 75% of the full scale range. If a gauge is not selected considering these criteria, it may result in fatigue of the Bourdon tube.
The normal temperature ranges for dry gauges are between -40C to 65C (-40F to 150F). The normal temperature ranges for glycerin-filled gauges are -25C to 65C (-13F to 150F). It is important to know the normal operating temperature of the environment for proper gauge use. Gauge accessories can extend temperature ranges further.