Regulator classification Working principle of safety shut-off valve When the signal pressure is abnormal and exceeds (overpressure type) or lower (de-pressure type) shut-off valve starting pressure setting value, the pneumatic film in the Sensor drives the collision block to move, so that the tripping mechanism acts. Under the action of the closing spring, the main valve flap quickly closes the valve port to protect the downstream equipment such as the pressure regulator and the measuring instrument. The working principle of the safety relief valve is used as the pressure of the pressure regulating cabinet (station) for the lower chamber of the main film to rise to the starting pressure of the discharge valve, which overcomes the force of the adjusting spring to drive the rod upward movement, under the action of the lever, The valve stem moves down to open the main disc and discharge the gas. When the pressure drops to the starting pressure setting due to the gas discharge, the valve stem moves up and the valve flap closes the valve port under the action of the return spring. Regulator maintenance Regulator common faults and troubleshooting measures Sensor
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1. Direct-acting voltage regulator The direct-type voltage regulator has small volume, large flow, simple structure, and convenient initial installation and maintenance. It has a wide range of applications and can be divided into high and medium pressure, high and low pressure, medium and medium pressure, medium and low pressure, etc. according to different inlet and outlet pressures. The disadvantage is that the pressure difference is large, the energy loss is much, and there is a phenomenon of panting and jumping in the small flow fashion.
According to the structure, it can be divided into two types: lever type and balanced valve core type:
1.1. The pull rod type series regulator transmits the force through the lever, and the outlet pressure of the regulator is set by the adjusting spring. When the flow rate downstream of the regulator increases, the outlet pressure P2 tends to decrease. At this time, the pressure in the lower chamber of the main regulator drops, so that the main film moves downward under the action of the adjusting spring; under the action of the lever, the valve The rod drives the flap away from the valve port, causing the regulator to open, thereby increasing the flow through the valve port and maintaining a constant downstream pressure. When the flow downstream of the regulator is reduced, its effect is reversed from the above process until the regulator is closed. 
1.2, the action of the balanced valve core regulator diaphragm (M) is transmitted to the valve (P) by the spool (S), and the outlet pressure is connected to the membrane (M) by the pressure tube, and the generated force and spring (D) )contend. The gas pressure of the skin is intended to close the valve, while the spring pressure is intended to open the valve (the fault is opened).
When there is no air flow, the spring fully opens the valve. When overpressure, the regulator closes and the valve pad (Q) and the valve (P) are integrated to ensure complete sealing. When the counteraction of the spring and the outlet pressure is balanced, the membrane-valve-valve combination remains stationary and the outlet pressure corresponds to the spring set point. When the flow demand increases, the outlet pressure drops, the effect of the spring is greater than the outlet pressure, and the valve opens until the outlet set pressure is restored. When the outlet pressure increases, the process is reversed. 
The inlet pressure acts in the balance chamber (B) to accurately and perfectly balance the on-off valve (Q) under all operating conditions.
During any adjustments, the shut-off valve should be opened very carefully and under extreme conditions to prevent strong airflow from damaging the downstream equipment of the regulator.
Proceed as follows:
1. According to the characteristics of the system, let a small amount of gas flow in step by step. Therefore, open the exhaust plug downstream of the regulator, and if there is difficulty, open the outlet valve a little.
2. Slowly open the inlet valve a little.
3. Reset the shut-off valve (if any)
4. After the outlet pressure is stable, first slowly open the inlet valve completely, and then slowly open the outlet valve completely.
The setting is done during the operation of the regulator. Open the inlet valve and the outlet end of the regulator slightly. The regulator (L or T) rotates clockwise to increase the pressure, or counterclockwise to decrease the pressure. 
A. Check the regulator for external leakage with a gas alarm device (or soap). (Note: odor residue after the release may cause the gas alarm instrument to alarm.)
B. Check the closing pressure of the regulator. Slowly close the valve at the outlet end of the regulator. Connect the pressure gauge to the outlet of the regulator and open the switch. After three minutes, record the closing pressure value and check if it is within the normal range. The regulator does not need to be repaired if the regulator is under normal pressure.
C. Clean the outside of the regulator.
D. Cleaning the inside of the regulator When the gas medium contains heavy dirt, the inside of the regulator should be cleaned regularly. According to the temperament and usage, every 3~6 months, the rubber parts that are easy to swell or age, such as: valve gasket, diaphragm, O-ring, etc., should be inspected or replaced regularly to ensure the safety and normal supply of gas. use.
When the medium is artificial gas, it is recommended to shorten the maintenance period to 1-3 months. The operation management department shall adjust the maintenance period as appropriate according to the temperament.
E. Before the maintenance, the inlet and outlet valves before and after the regulator should be closed to release the pressure; when reassembling, care should be taken to avoid damage to parts such as valve ports and membranes. After assembly, check whether the movable parts can move flexibly. After the repair and assembly, follow the regulator ventilation operation method to make the maintenance settings, and use soap to check all the joint sealing parts for external leakage.
1. If there is no gas passing downstream of the pressure regulating valve, it may be:
1) Insufficient inlet flow, no gas passing through the pilot
2) Filter blockage
3) The cutter is triggered
4) The diaphragm of the regulator is damaged.
2. If the regulator outlet pressure drops, it may be:
1) Insufficient port flow
2) The actual flow exceeds the regulator design flow
3) Inlet filter blocking
4) Spring break
5) The signal pipeline inside the pilot to the regulator is blocked or damaged.
3. The increase in pressure at the outlet of the regulator may be:
1) Gland or valve seat wear
2) The gasket accumulates dust
3) The membrane is damaged or broken
4) The regulator stem is not flexible
4, regulator vibration
1) The pressure tube connection is misaligned or does not meet the installation requirements
2) The flow is too low
3) The diameter of the tooth valve hole on the pilot is incorrect.
5, the regulator pressure is not high
1) The regulator valve gasket expands and the valve port does not reach the proper opening
2) The pilot adjusts the spring deformation and does not reach the design pressure.
6, the regulator outlet pressure is unstable and gasping
1) More gas impurities
2) Sudden change in gas pressure or flow
3) High outlet pressure and large fluctuation of front pressure Regular inspection Regulator inspection steps:
First, slowly close the outlet valve and check the pressure in the pipeline between the regulator and the outlet valve. If the system is operating normally, the outlet pressure will temporarily rise due to the shutdown and then gradually stabilize. If the outlet pressure continues to rise, it means that the pressure regulating valve port cannot be sealed, causing the system to be abnormal. At this point, the regulator should be turned off. 