The main role of the regulator station in the gas transmission and distribution system is to regulate and stabilize the system pressure and control the gas flow, to prevent the equipment after the regulator from being worn out and clogged, and to protect the system from low or over-pressure outlet pressure.

The regulator station consists of regulators, valves, filters, safety devices, bypass pipes and measuring instruments. Some regulator stations are equipped with metering equipment, in addition to regulating pressure, but also play a role in measurement, so it is called as a regulator metering station.

First, the composition of the regulator

(A) valve

In order to overhaul the regulator, filter and cut off the gas source when the regulator is out of service, the import and export of the regulator station must be equipped with valves. In addition, 10 meters away from the regulator outside the total import and export pipeline should also be set on the valve. During normal operation, this valve is normally open. When an accident occurs at the regulating station, it is not necessary to approach the regulating station to shut off the valve to cut off the gas source to prevent the accident from spreading. When the regulator is overhauled, the valve should also be closed to cut off the gas source.

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 (ii) Filter

Various impurities contained in the gas are accumulated in the regulator and safety valve, which will impede the cooperation between the spool and the valve seat, and affect the normal operation of the regulator and the safety valve, therefore, it is necessary to install a filter at the entrance of the regulator. Regulator station commonly used bristle or glass wire as packing filter. As shown in Figure 7-1-1. Solid particles brought into the filter by the gas hit the baffles and accumulate in the lower part of the filter, where they are periodically discharged by the sweep holes 5. Small particles of solids and dust particles remaining in the gas are impeded on the filter element. Filter material is mounted between the two metal grids, cleaning should first remove the upper cover, and the filter element out of the pick. Filtering community before and after the differential pressure gauge should be installed, according to the measured pressure drop can determine the clogging of the filter. Under normal working conditions. The pressure loss of the gas through the filter shall not exceed 10kPa, and should be removed and cleaned when the pressure loss is too large.

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(iii) safety valve

Due to the regulator film rupture, close poorly or regulation failure, it will make the regulator lose the automatic regulation and pressure reduction effect, causing a sudden rise in the outlet pressure, resulting in system overpressure, endangering safety, therefore, the regulator station must be set up with a safety valve.

The outlet pressure of the regulator room is controlled by the safety cut-off valve and safety relief valve. The safety cut-off valve controls the upper and lower limits of pressure, and the safety discharge valve controls only the upper limit of pressure. The discharge pressure of the discharge valve should be lower than the closing pressure of the shut-off valve. When the regulator is working normally, only when it should be shut off when the closure is not tight (due to impurities accumulated on the valve, wear and tear, etc.), the gas is discharged into the atmosphere. At this point, the amount of gas flowing through the poorly closed valve is greater than the amount of gas used, and the outlet pressure increases. In order to avoid high outlet pressure, the excess gas must be discharged into the atmosphere.