After China's accession to the WTO, along with the integration of the world economy, the global manufacturing industry to accelerate the transfer of mainland China has been the general trend, China will gradually develop into a world-class manufacturing base. Connoisseurs predict that the obvious advantages of Guangdong, especially the Pearl River Delta region, will develop into a world ball valve production center within ten years. At the same time, because in recent years, China's annual imports of molds with nearly 1 billion U.S. dollars, of which precision, large, complex, long-life molds account for the majority, so from the point of view of reducing imports of such high-grade molds in the market will gradually increase the proportion of the share.

Pressure reducing valves, safety valves, pressure stabilizing valves, pressure relief valves are pressure valves, mainly the difference in function.

Pressure reducing valve is a high pressure medium to reduce the pressure of the medium of low pressure equipment, the characteristics of the valve, is in the case of constant changes in the inlet pressure, to maintain the export hear pressure and temperature values within a certain range.

Safety valve is used to prevent boilers, pressure vessels and other equipment or piping due to overpressure and damage to the valve. When the pressure is slightly higher than the normal working pressure, the safety valve automatically opens, so that the pressure drops. When the pressure is slightly lower than the normal working pressure, the safety valve automatically closes, stops discharging fluid and maintains the seal.

Pressure relief valve is mainly used in the occasion of excessive pressure, when the pressure is greater than the set value of the valve piece is open in time to release the pressure, the pressure is reduced to return to its original position, and the difference between the safety valve is not very big, the pressure relief valve is mostly used for liquids, safety valves are mostly used for gases, steam.

Pressure stabilizing valve is an area of the medium to maintain a certain pressure range of equipment. And the difference between the pressure reducing valve:

Pressure reducing valve: no matter how the inlet pressure changes, it reduces the outlet pressure to the rated value and acts as a pressure reducer.

Pressure stabilizing valve: maintains a constant upstream pressure regardless of changes in downstream pressure and demand.

Safety valves and pressure reducing valves are two types of valves, which are specialized valves. Among them, safety valve belongs to the safety relief device, is a special valve, only in the working pressure exceeds the permissible range of action, to play a protective role in the system. Pressure reducing valve belongs to the process valve, can make the high-pressure logistics decompression, in order to meet the requirements of the pressure after the system, its work process is continuous.

Pressure reducing valve selection criteria:

1, for soft sealing pressure reducing valve, there shall be no leakage in the specified time; for metal sealing pressure reducing valve, the leakage shall be no more than 0.5% of the maximum flow rate;

2, in the given spring pressure level range, so that the outlet pressure in the maximum value and the minimum value of the pressure reducing valve can be continuously adjusted, there shall be no jamming and abnormal vibration;

3、When the outlet flow rate changes, the outlet pressure deviation value of direct-acting type is not more than 20%, and that of pilot-operated type is not more than 10%;

4, the inlet pressure changes, the direct-acting type of export pressure deviation is not greater than 10%, the pilot type is not greater than 5%;

5, bellows direct-acting pressure reducing valve for low-pressure, small diameter steam medium;

6, pressure reducing valve has a wide range of applications, in steam, compressed air, industrial gas, water, oil and many other liquid media equipment and piping can be used, the amount of media flow through the outlet of the pressure reducing valve, generally with mass flow or volume flow rate;

7, usually, the pressure reducing valve after the valve pressure should be less than 0.5 times the pressure before the valve;

8、Direct-acting diaphragm pressure reducing valves are suitable for low and medium pressure, small and medium diameter air and water media;

9、Pilot-operated piston type pressure reducing valves are suitable for various pressures, various calibers, various temperatures of steam, air and water media, and if made of stainless and acid-resistant steel, they can be applied to various corrosive media;

10、Pilot-operated bellows-type pressure reducing valves, suitable for low pressure, medium and small diameter steam, air and other media;

11, pressure reducing valve inlet pressure fluctuations should be controlled in the inlet pressure given value of 80% ~ 105%, such as exceeding the range, the performance of the pre-pressure reduction will be affected;

12、Pilot-operated diaphragm type pressure reducing valves for low pressure, medium pressure, medium and small diameter of steam or water and other media;

13, usually the pressure reducing valve after the valve pressure should be less than 0.5 times the pre-valve pressure;

14, each spring of the pressure reducing valve is only applicable in a certain range of outlet pressure, beyond which the spring should be replaced;

15, the medium is air or water (liquid) occasions, it is generally appropriate to use direct-acting diaphragm type pressure reducing valve or pilot operated diaphragm type pressure reducing valve;

16, in the media working temperature is relatively high occasions, the general choice of pilot operated piston type pressure reducing valve or pilot operated bellows type pressure reducing valve;

17, the medium for the occasion of steam, it is appropriate to use the pilot piston or pilot bellows type pressure reducing valve;

18, in order to operate, adjust and maintain the convenience of the pressure reducing valve should generally be installed in the horizontal pipeline.