Selection and installation posture of pressure gauges-chemical pump manufacturers take you to understand
In petrochemical production, the so-called pressure refers to the force that acts uniformly and vertically on a unit area by a gas or a liquid. Especially in the petrochemical production process, pressure and vacuum measurement are often encountered. High pressure, ultra high pressure and specific pressure are much higher than atmospheric pressure.
In petrochemical production, the so-called pressure refers to the force that acts uniformly and vertically on a unit area by a gas or a liquid. Especially in the petrochemical production process, pressure and vacuum measurement are often encountered, high pressure, ultra high pressure and vacuum measurement much lower than atmospheric pressure.
Today we will talk about how to install a pressure gauge
Installation and application of pressure gauge
Radial means that the connection caliber of the pressure gauge is in the shape of the dial and is directly installed.
Axial means that the connection diameter of the pressure gauge is T-shaped with the dial. It is also divided into the central axis and off-axis (lower axis) installation.
Threaded connections are M20 × 1.5; M14X1.5; M12X1.5; G1 / 2; G3 / 8; NPT1 / 2; NPT1 / 4 (other).
Flange connections are manufactured according to customer requirements.
Instrument fixing method:
Direct mounting, front band mounting, rear band mounting, U-clip mounting
Selection of measuring range
When measuring stable pressure, the normal operating pressure value should be 1/3 --- 2/3 of the upper limit of the measuring range of the instrument;
When the side measurement is high and medium pressure, the normal operating pressure value should not exceed 1/2 of the upper limit of the measuring range of the instrument.
Select according to the use environment and the nature of the measurement medium
In the environment with strong corrosive atmosphere, more dust, and easy to spray liquid, you should choose the appropriate shell material and protection level according to the environmental conditions.
A. Measurement of general media
When the pressure is -40kPa --- + 40kPa, diaphragm pressure gauge should be used.
When the pressure is above + 40kPa, a spring tube pressure gauge or a bellows pressure gauge is generally used.
B. Dilute nitric acid, acetic acid and other general corrosive media should use acid-resistant pressure gauges or stainless steel diaphragm pressure gauges.
C. Dilute hydrochloric acid, hydrochloric acid gas, heavy oils and similar mediums with strong corrosiveness, containing solid particles, viscous liquids and other media should use diaphragm pressure gauges or diaphragm pressure gauges. The material of the diaphragm and diaphragm must be selected according to the characteristics of the measurement medium.
D. For crystallization, scarring and high viscosity media, flange diaphragm pressure gauges should be used.
E. In the case of strong mechanical vibration, an earthquake-resistant pressure gauge or a marine pressure gauge should be selected.
F. In flammable and explosive occasions, if an electrical contact signal is required, an explosion-proof pressure controller or an explosion-proof electrical contact pressure gauge should be selected.
Selection of installation pressure points
1. To make holes in pressure pipes, you must use the mechanical hole method (electric drill or hand drill). Note: The holes in air pressure pipes can be cut by gas. After cutting, the hole is polished with a round file; the pressure is taken from the source. The end of the component must not exceed the inner wall of the equipment or pipe.
2. When there is a protruding object (such as a temperature measuring element) in the pipeline, the pressure source component should be installed in front of it.
3. The installation location of the pressure source component should be selected in a place where the medium flow beam is stable, and avoid being in the area of pipeline bending, bifurcation and vortex formation of the flow beam.
4. When pressure must be taken near the regulating valve, if the pressure taking port is in front of it, the distance from the valve should not be less than 2 times the pipe diameter; if the pressure taking port is behind, the distance from the valve should be not less than 3 times the pipe. path.
5. When measuring the pressure of turbid media with dust, solid particles or sediments, the source-receiving components should be installed at an oblique upward direction. It should be installed at a sharp angle along the horizontal process pipeline.
6. When detecting the pressure of liquid, steam and condensable gas whose temperature is higher than 60 ℃, the source part of the pressure gauge installed in situ should have ring or U-shaped condensation bend.
7. When pressure source components are installed on horizontal and inclined process pipelines, the orientation of the pressure source should meet the following requirements:
The gas pressure is measured in the upper half of the process pipe.
When measuring the liquid pressure, the lower half of the process pipe is within a range of 0 to 45 degrees with the horizontal centerline of the process pipe.
When measuring the steam pressure, the upper half and the lower half of the process pipeline are within the range of 0 to 45 degrees with the horizontal centerline of the process pipeline.