How to Properly Install the Pressure Gauge?

To perform pressure testing, a measuring system is actually needed. In order to achieve accurate measurement, besides correctly selecting and verifying instruments, attention must be paid to the correct installation of the entire system. If only the shock-resistant pressure gauge itself is accurate, its indication cannot fully represent the actual parameters of the tested medium because the measurement system error is not equal to the instrument error. The correct installation of the system includes the opening position of the pressure measuring port, the reasonable laying of the connecting pipe, and the correct installation position of the instrument.

Selection of pressure gauges pressure port location

• When installing intelligent pressure gauge and other pressure gauges, areas where pipelines bend, branch off, and water flows form eddies should be avoided.

• When there are protrusions (such as temperature measuring elements) in the pipeline, the pressure measuring port should be taken in front of them.

• When taking pressure near the regulating valve, if the pressure tapping port is in front, the distance from the valve should not be less than twice the pipe diameter; if the pressure tapping port is in the back, the distance from the valve should not be less than three times the pipe diameter.

• For wider containers, the pressure measuring port should be located in an area where the fluid flows smoothly and without eddies. In short, the position of the measuring hole determined in the process flow should be able to ensure the selected process parameters are measured.

Layout of connecting pipes for pressure gauges

The horizontal section of the connecting pipe should have a certain slope to facilitate the discharge of condensed liquid or gas. When the measured medium is a gas, the pipeline should be inclined towards the pressure measuring port; when the measured medium is a liquid, the pipeline should be inclined towards the pressure measuring instrument; when the measured parameter is a smaller pressure difference value, the inclination can be slightly larger.

In addition, if the air duct is at the upper or lower corner, install a condensate discharge device at the lowest point or an exhaust device at the highest point according to the medium in the air duct to ensure that the condensed liquid does not accumulate in the pipeline for a long time. Liquid or gas will affect the accuracy of the measurement. The condensed liquid or gas should be regularly discharged.

• The pressure gauge should be installed vertically to the horizontal plane;

• The orientation of the instrument should face the direction that is easy to operate and observe;

• The end of the pressure source component should not exceed the inner wall of the equipment or pipeline;

• For the same pipeline, pressure should come first and temperature should come later, and the hole spacing should be ≥200mm.

  Note: The measuring points of the measurement protection and automatic control instruments cannot use the same measuring hole. This is mainly to avoid mutual interference during daily maintenance, which affects the protection and interlocking instruments, thereby adjusting other equipment through interlocking.

• When testing turbid materials such as dust, solid particles, or sediment, the source components on vertically and inclined equipment and pipelines should be tilted upward, and the horizontal pipeline should be installed at a sharp angle to the flow of materials.

General installation notes for pressure gauges

• When installing the gauge, it is crucial to follow the guidelines of pressure gauge suppliers, such as tightening the connection to the recommended torque value, to ensure correct installation. 

• In general, the installation height should be at eye level with people, about 1.5m. For high-pressure gauges, the installation height should be higher than the head of an ordinary person.

• When measuring the pressure of liquid or steam media, errors caused by liquid columns should be avoided. The pressure gauge should be installed on the same horizontal plane as the pressure tapping port, otherwise, the display value of the pressure gauge must be corrected.

• At the connection of the pressure gauge, suitable materials should be selected as the seal gasket according to the measured pressure and the properties of the measured medium to prevent leakage.

• The thickness of the pressure guiding tube should be suitable, generally 6-10mm, and the length should be as short as possible, otherwise, measurement delay will be caused.

• The pressure gauge should be installed at normal temperature as much as possible, with a relative humidity of less than 80%, low vibration, less dust, and no corrosive substances. For electric pressure gauges, electromagnetic interference should be avoided as much as possible.

• When two pressure gauges are installed side by side, the distance between the instrument housings should be kept between 0-50mm.

• The installation position of the pressure gauge should avoid frequent mechanical operations to avoid damaging the pressure gauge during operation of other equipment, such as the manual operation of valve handles.

• When drilling holes in the pressure pipeline, mechanical drilling methods (electric or hand drills) must be used.

  Note: Gas cutting can be used for holes on the air duct. After cutting, the hole should be inverted and filed flat.

• A shut-off valve should be installed between the pressure tapping port and the pressure gauge for maintenance purposes. The shut-off valve should be installed near the pressure tapping port.