Selection of flange pressure transmitters
Thread Content
Flange pressure transmitters come in two forms: one with a direct flange connection, and the other with a capillary flange connection. Which type is more commonly used? Are there any differences in when it is used?
Personal opinion: 1. Diaphragm pressure transmitters are suitable for enclosed environments, as the diaphragm has extensive contact with the medium； Especially for the measurement of viscous or paste-like media, highly corrosive liquids, or media rich in particles. Not prone to clogging, easy to clean. It needs to be used together with a flushing ring ； 2. The main difference between direct flange connection and capillary flange connection lies in whether a capillary is present or not ； 3. When the operating conditions permit in terms of temperature, it is recommended to use a direct flange connection, as this reduces the measurement errors and response time caused by capillaries, and the cost is also slightly lower ； 4. If the wall temperature of the device is high, a capillary flange connection can be used to prevent the transmitter from reaching too high a temperature; at the same time, attention should be paid to heating and insulation of the capillary (since high-temperature silicone oil has poor pressure conductivity at low temperatures) ； The transmitter can also be installed in a location where it is easy to observe.
It should mainly depend on the convenience of maintenance; if it is difficult to perform manual operations at the location where the transmitter is directly installed, then it is better to use a capillary tube for connection.
Direct flange transmitters can be used to measure pressure directly, as well as to conveniently measure the level of liquids in open systems. For measuring the level in closed containers, a pressure tap can be installed on the gas side; in cases where condensation occurs, a condensate tank can be placed below the transmitter. A single-capillary transmitter can be considered similar to a direct flange transmitter, with the additional advantage of being suitable for use in high-temperature environments.
The direct-connection type should be the preferred choice; if the location of the pressure measurement point makes maintenance difficult, then a capillary type should be used.