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The switching sequence of the three-valve group of the differential pressure transmitter
Regarding the three-valve group, when the equal differential pressure transmitter is in use, the positive pressure chamber is closed to make it in a small range; the negative pressure chamber is closed to make it in a large range. Why is this? The following editor tells you how to arrange the switching sequence of the three-valve group of the differential pressure 3-transmitter? Let me talk about the differential pressure transmitter with H, L, some people call H=positive pressure chamber, and L is called negative Pressure room, of course, in some occasions, some people call H as high voltage room and L as low voltage room. And the three valve groups have high-pressure valve, low-pressure valve and intermediate balance valve, so as long as the balance valve is not opened, only the high-pressure valve or low-pressure valve is closed. Unless there is a leak, the pressure should remain unchanged. Since the positive s is closed, the positive pressure side is no longer under pressure. If the negative pressure increases, it means that it is too small. When the negative pressure decreases, the system is too large. Turn off the negative pressure, the same result. , When the three-valve group is used in conjunction with a differential pressure transmitter, the function is to make a passage or disconnection between the positive and negative pressure measuring chambers and the pressure leading point, or to make a passage between the positive and negative pressure measuring chambers. The primary function is to use a balance valve during installation and disassembly. In addition, the differential pressure range is generally very small. If the manufacturer's overload capacity is not strong, it is easy to cause damage. For example, if the differential pressure is 60KPa and the pipeline pressure is 1MPa, if there is no balance valve, whether the positive pressure chamber or the negative pressure chamber is taken first, the differential pressure on both sides will immediately cause the differential pressure on both sides to far exceed the set value. Since the pre-emptive player will directly communicate with the atmosphere, which is equivalent to 0.1MPa, the operation is fatal. The operating procedure when putting in the differential pressure transmitter: First, open the two exhaust sides of the differential pressure transmission road, then open the balance idler, and then slowly open the two service stop gardens, and the air in the pressure guiding tube becomes a line. , Suddenly prepare the lake to hit the drain valve, and then close the balance valve, the transmitter can be put into operation. When the ordinary three-valve group is used in conjunction with a differential pressure transmitter, the following steps must be followed to first open the balance valve and close the two cut-off widths to complete the zero check of the transmitter.
Two principles should be paid attention to when using the three-valve group of the instrument
(1) The loss of condensed water or isolation fluid in the pressure guiding tube is not allowed;
(2) The measuring element (diaphragm or bellows) cannot be pressed or heated;
The operation of the three valve groups should be
(1) Turn on positive pressure;
(2) Close the balance valve;
(3) Open the negative pressure valve.
The shutdown sequence is opposite to the startup
(1) Close the negative pressure valve;
(2) The balance valve is opened;
(3) Close the positive pressure valve.
Differential pressure transmitter
The switching sequence of the three-valve group, the switching procedure of the three-valve group
It is necessary to understand the three-valve group first in order to understand the switching sequence of the three-valve group, the stop and the structure of a balanced valve group. Its structure is a kind of valve body, two cut two compartments, five valve groups and four doors. In addition, Chongqing Jiuhuan Electromechanical and Three Adjustment Streets are combined. The three valve groups are valve differential pressure transmitters. The pressure measurement chamber passes and so on. The three-valve group is generally equipped with a switching sequence. The main function of the three-valve group is to make the positive and pressure points conduct or disconnect, or to disconnect the positive and negative measuring chambers.
The sequential operation sequence of the three-valve group switch is as follows:
The inside of the three-valve group is composed of three valves that communicate with each other. According to the role of the three valves in the system, they are divided into high-pressure, low-pressure valves and balance valves. According to the installation specifications of the three-valve group, under normal circumstances, the left side is the high pressure valve, the right side is the low pressure valve, and the middle is the balance valve. The opening and closing of the three-valve group is carried out in the order of operation, and the wrong switching sequence of the three-valve group will cause malfunctions. If the three valve groups are to be opened, the opening sequence of the three valve groups is to open the high-pressure valve first, close the balance valve, and finally open the low-pressure valve. If three valve groups are to be closed, the operating sequence of the three valve groups is to first close the low pressure valve when closing, then open the balance valve, and finally close the high pressure.