1. Installation of differential pressure transmitter
与差压源之间导压管的长度应尽可能短，一般在3~50m范围内，其内径不宜小于8mm；导压管应保持有不小于1:10的倾斜度，即水平方向敷设10m时，其两端高度差为1m。 The length of the pressure guiding tube between the differential pressure transmitter and the differential pressure source should be as short as possible, generally within the range of 3 ~ 50m, and its inner diameter should not be less than 8mm; the pressure guiding tube should maintain an inclination of not less than 1:10. That is, when laying 10m in the horizontal direction, the height difference between the two ends is 1m. The slope of the impulse pipe should meet the following requirements: When the measured medium is a gas, the cold gel in the gas should be able to automatically flow back to the process pipe or the middle of the equipment along the impulse pipe, so the transmitter installation position should be high For the pressure source, if this cannot be done in actual installation, a liquid collector and a drain valve should be installed at the lowest point of the pressure guiding pipeline. When the medium to be measured is liquid, it should be able to flow the gas precipitated in the liquid back to the process pipe or equipment along the impulse pipe. Otherwise, a gas collector and a gas release valve should be installed at the highest point of the impulse pipe. Therefore, the installation position of the transmitter should be lower than the pressure source. In short, the slope and aspect of the impulse pipeline must ensure that in the impulse pipeline and differential pressure transmitter, only a single-phase medium (gas phase and liquid phase) exists to ensure the stability of the measurement and prevent additional errors.
When the measured medium is steam, a condensing container should be installed in the pressure-conducting pipeline to prevent the differential pressure transmitter from being damaged due to the entry of high-temperature steam. The installation position of the condenser should ensure that the condensate levels in the two impulse pipes are kept at the same level for a long time. The pressure piping from the condensing container to the transmitter should be laid according to the requirements when the measured medium is liquid.
For corrosive media, appropriate isolation equipment should be installed in the pressure-conducting pipeline to prevent the differential pressure transmitter from being corroded. In the case where the measured medium has a large viscosity, is easy to precipitate or crystallize, the gas / liquid phase transition temperature is low, and is easy to polymerize, the corresponding isolation equipment should also be adopted to prevent the impulse tube from being blocked.
的使用注意事项使用差压变送器时应注意以下三点： 2. Notes on the use of differential pressure transmitters The following three points should be noted when using differential pressure transmitters:
(1) Before using the differential pressure transmitter, it is necessary to recalibrate its measurement range, zero drift, accuracy, and static pressure error.
(2) After the transmitter is installed, check the working pressure, working temperature, measurement range, and drift of the various transmitters once before driving. See if it is consistent with the actual situation. If there is any discrepancy, you must find out the cause and correct it before driving.
(3) When opening and disabling, the instrument should be protected from unidirectional static pressure.
的上方，其中阀1和阀3分别为高压和低压切断阀，阀2 为平衡阀。 In order to avoid unidirectional pressure during use, each differential pressure transmitter should be provided with a three-valve assembly, which is usually installed above the differential pressure transmitter , of which valve 1 and valve 3 are high pressure and low pressure shut-off valves respectively. , Valve 2 is a balanced valve. The balance valve 2 is used to protect the differential pressure transmitter and facilitate the zero position when the meter is opened and stopped. When opening the differential pressure transmitter, the balance valve 2 should be opened first, and then valve 1 and valve 3 should be opened. When valve 1 and valve 3 are fully opened, valve 2 should be closed. When the differential pressure transmitter is deactivated, the balance valve 2 should also be opened first, and then the valves 1 and 3 should be closed respectively. Opening or deactivating the differential pressure transmitter in the above order can prevent the differential pressure transmitter from being subjected to a single Overload to static pressure; for differential pressure transmitters with cold gel or isolating fluid, the cold gel or isolating fluid can also be prevented from being washed away.
The above is the entire content of the installation and use of the differential pressure transmitter.