Mounting position of the pressure transmitter and installation precautions

Brief introduction

Pressure transmitters can be used to measure flow, liquid level and other applications that require accurate measurement of differential pressure and pressure, such as pressure transmitters, differential pressure transmitters, and liquid level transmitters. The correct installation of the transmitter and impulse tube directly affects the accuracy of the pressure measurement. Therefore, it is very important to master the correct installation of the transmitter and impulse tube.

Due to the needs of the process, and sometimes in order to save the material of the impulse pipe and other economic reasons, the transmitter is often installed in the site with harsh working conditions, in order to reduce the severity of the working conditions of the pressure transmitter as much as possible, the transmitter should be installed as far as possible in a place where the temperature gradient and temperature change are small, and there is no shock and vibration.

Note: The medium to be measured should not allow freezing, as this will damage the sensing element isolation diaphragm and cause damage to the pressure transmitter or differential pressure transmitter.

Installation location

The position of the pressure transmitter on the process piping is related to the medium to be measured. The following should be taken into account when installing:

1. Try to avoid direct contact between the transmitter and corrosive or overheated test media.

2. It is necessary to prevent the debris from being deposited in the impulse pipe.

3. The impulse tube should be as short as possible.

4. The pressure of the liquid column in the impulse pipe on both sides should be balanced.

5. The impulse pipe should be installed in a place with small temperature gradient and temperature fluctuation.

When measuring liquid flow, the pressure tap should be open on the side of the process pipe to avoid sedimentation of the dross. At the same time, the transmitter should be installed next to or below the pressure take-off to allow air bubbles to be discharged into the process pipe. When measuring gas flow, the pressure tap should be open at the top or side of the process pipe. The transmitter should be installed next to or on top of the process pipe so that the accumulated liquid can easily flow into the process pipe. Use a transmitter with a pressure chamber fitted with a side bleed valve, and the pressure take-off should be open on the side of the process pipe. For example, when the medium to be measured is liquid, the relief valve of the pressure transmitter should be installed on it in order to exclude the gas seeping into the medium to be measured. When the medium to be measured is a gas, the relief valve of the transmitter should be installed underneath in order to drain the accumulated liquid. When the pressure chamber is rotated 180°, the relief valve above it can be changed to the bottom.

The pressure transmitter can be mounted directly at the measuring point, on a wall, or on a pipe using a mounting plate (transmitter attachment) clamp. The pressure impedion connection hole on the pressure capacity chamber of the pressure transmitter is a threaded hole, and the impasse connection hole on the joint is the inner cone pipe thread (or external thread), and the transition joint with the cone pipe thread of the impulse joint can be selected according to the need. The pressure transmitter can be easily removed from the process 1 pipe, and the two bolts that fasten the joint are unscrewed. By turning the joint, you can change the center distance of its connector. In order to ensure that the joint is sealed, the following steps should be followed when tightening: the two fastening bolts should be tightened evenly with wrenches alternately, and the final tightening force distance should not be tightened at one time. Sometimes, for ease of installation, the pressure chamber on the transmitter body can be rotated. As long as the pressure chamber is in the vertical plane, the rotation of the pressure transmitter wood does not produce a change in the zero position. If the pressure chamber is installed horizontally (e.g. when measuring the flow rate on a vertical pipe), the influence of the liquid column pressure due to the different height of the impulse pipe must be eliminated; That is, reset the zero position.