Select differential pressure transmitter based on the selection criteria of differential pressure transmitter
Date: 2013-12-27Read: 6
as the name suggestsDifferential pressure transmitterThe measured result is the pressure difference, i.e. △ P=ρ g △ h.Differential pressure transmitterUsed to measure the liquid level, density, and pressure of liquids, gases, and vapors, and then convert them into electrical signals for output.
Differential pressure transmitterSelection criteria:
⑴ Measurement range, required accuracy, and measurement function;
⑵ The environment faced by measuring instruments, such as the industrial environment of petrochemicals, has the presence of potentially hot (toxic) and explosive atmospheres, as well as high ambient temperatures;
⑶ The physical and chemical properties and states of the tested medium, such as strong acid, strong alkali, viscosity, easy solidification crystallization, and vaporization conditions;
Changes in operating conditions, such as changes in medium temperature, pressure, and concentration. Sometimes it is also necessary to consider the changes in gas and liquid phase concentrations and densities from driving to reaching normal sales parameters;
The structure, shape, size, equipment accessories inside the container, and various inlet and outlet material pipe openings of the tested object container must be considered, such as towers, solution tanks, reactors, boiler steam drums, vertical tanks, spherical tanks, etc;
Other requirements, such as environmental protection and hygiene requirements;
The selection of engineering instruments should have a unified consideration, requiring the reduction of specifications and varieties as much as possible, and the reduction of spare parts to facilitate management;
Actual process situation:
① To determine the physical and chemical properties and cleanliness of the medium, conventional differential pressure transmitters and float type liquid level transmitters also need to choose the material of the part in contact with the medium;
② Single flange differential pressure transmitter can be used for some suspended solids, foam and other media. Some easily precipitate and crystallize using plug-in double flange differential pressure transmitters;
③ Consider which type of device the tested object belongs to. For example, in the case of tanks, if the tank has a small volume, the measurement range may not be too large, while if the tank has a large volume, the measurement range may be larger;
④ For the liquid level of high viscosity media and high-pressure equipment, due to the inability of the equipment to open holes, radio frequency liquid level gauges can be used for measurement;
⑤ In addition to measurement methods and technical issues, there is also the issue of instrument investment.