Gas valves occupy an important position in the gas industry. The Ministry of Construction attaches great importance to the normative construction of gas valves. The industry standard for gas valves is CJ3005-1992 "General Technical Requirements for Gray Cast Iron Valves for Town Gases", CJ3055-1995 "Test and Inspection of Gas Valves", CJ3056-1995 "General Technical Conditions for Ductile Iron and Cast Steel Valves for Urban Gases", and in June 2002, passed the industry standard for "Manual Manual Gas Valves". The formulation and promulgation of these standards have regulated the valve industry, promoted the progress and development of gas valves, and promoted the development of the gas industry; provided reference for development, production, and use of units; improved understanding of the difference between gas valves and general valves The safety margin of the gas valve is guaranteed; it is welcomed by the gas counterparts.
First, RX series oil sealed plug valve
In the 1980s, China's gas was mainly made of artificial coal, and there were more impurities and "gas glue" in artificial coal. The traditional single-plate sluice valve was more and more unable to adapt to gas conditions. The need for such valves is generally "closed" and the stem is killed. We refer to the RX series of gas-sealed plug valves developed by Japanese technology to solve the problem of tight seal and stem bite. problem.
Second, RZ series gas parallel parallel gate valve
With the development of the gas industry and the establishment of gas plants, gas-specific valves with large or even large nominal diameters are required. The parallel double-gate gate valves for RZ series gas are used to solve the problem of artificial gas formation. The maximum diameter is up to one. 1600mm.
The parallel double gate valve can scrape off the “gas glue” on the sealing surface during the opening and closing process, which solves the big problem that the gas impurities adhere to the sealing surface and affect the valve sealing;
It is equipped with a valve stem cover to protect the valve stem from "gas glue";
The lower part of the valve has a drain hole side cover to clean the garbage falling on the bottom of the valve chamber;
The full-bore design has a small flow resistance and can pass through the pig;
The valve body uses a specially designed "squirrel cage frame rib" to reduce the overall weight of the valve and enhance the strength and rigidity of the casing;
The RZ series gas gate valve housing is made of gray cast iron and the price is low. Seventh, the series of gate valves have a fully enclosed opening and closing indicator, so that the operator can clearly understand the state of the valve.
Third, RQZ series of ductile iron gas parallel double gate valve
As China's natural gas enters the town, according to the characteristics of natural gas, RQZ ductile iron gas parallel double gate valve is developed. In addition to retaining the characteristics of RZ series gate valve, the selected material enhances the wear resistance of the valve. Increase the pressure level to the high pressure class B.
Fourth, butterfly valve
Compared with the above-mentioned valves, the butterfly valve is light in weight, large in diameter and low in price. Some gas companies used butterfly valves in the early 1980s. After ten years of use, it is generally considered that the effect is not good.
First, the sealing and isolation width of the butterfly valve is too narrow, which may cause over- or under-position during the closing of the valve flap, which affects the sealing;
Second, the valve flap is in the middle of the valve cavity, and the flow resistance is large, and cannot pass through the cleaner;
Third, since a part of the sealing pair is rubber or polytetrafluoroethylene, it is easily damaged or peeled off during gas flushing, and the service life is short.
Practice has proved that except for special positions, butterfly valves should not be used on gas pipelines. Some gas companies that have used butterfly valves are (or are considering) replacing other valves.
Five, slab gate valve
The slab gate valve is a general-purpose valve that has been used in gas pipelines in recent years. The flow resistance is small at full diameter, and the seals on both sides are formed by pressing a Teflon or rubber O-ring on the ram. This valve is fully closed or When the valve is fully open, it can't be airless in the middle cavity. It is not convenient for the user to quickly judge whether the valve is closed when repairing. If the air is not in the middle cavity, the opening and closing torque will increase rapidly. Some manufacturers make the diameter reduction, such as DN200 caliber. The inner diameter is only 150mm, so users should pay special attention. Therefore, the slab gate valve is suitable for applications where the pressure level is low and the nominal diameter is small.
Sixth, TRZ series elastic sealing gas gate valve
TRZ series elastic sealing gas gate valve is a special gas valve that is different from slab gate valve. The valve has the same characteristics as the elastic valve seat structure of the fixed ball valve. The sealing seat on both sides of the ram adopts an elastic floating structure. The sealing surface is always close together during the opening and closing and opening and closing process, and can compensate for the wear and tear of the seal. It is suitable for high pressure level system; the valve can reach no air in the valve cavity when fully open and fully closed, even if the remaining gas in the valve cavity is released, there is no pressure in the valve cavity.
Seven, RQ series ball valve
RQ series fixed ball valve is specially designed and manufactured for the gas industry. This valve combines the characteristics of various types of ball valves at home and abroad, and then developed according to China's national conditions, suitable for gas long-distance trunk lines and city gas facilities.
The advantages are as follows:
Fire resistance, fire high temperature burnt the PTFE material on the sealing seat, the metal sealing seat and each sealing part can form a metal-to-metal sealing structure, prevent the gas medium from spreading, and prevent the disaster from continuing to expand;
Anti-static, the static electrode formed by the ball valve during the opening and closing process is easy to ignite the gas, and the ball valve introduces static electricity into the ground to ensure the safety of the device;
The limit position is locked, the ball valve is a rotating mechanism, which is easy to cause 360-degree rotation. In addition to the limited position mechanism, it can be locked to prevent accidents caused by operator misoperation or unauthorized operation by non-operators;
The ball valve stem seal is designed with anti-valve impact device and special O-ring seal. The torque is smaller than the similar ball valve, the operation is light, and the opening and closing is fast.
Eight, the emergency shut-off valve for the regulator
The emergency shut-off valve for pressure regulators is an important safety protection device in gas transmission and distribution systems. The emergency shut-off valve is equipped with an emergency tripping mechanism on the upper or side position of the shut-off valve. It is also integrated with the regulator body, and is also integrated with the filter. Its function is to cause the pressure regulator to malfunction, resulting in overpressure or After the pressure is reduced, the air source is turned off urgently to ensure safety. The large-scale use of natural gas in the city has increased the pressure level of the pipe network. The failure of the pressure regulator will bring catastrophic consequences to the city, and the domestic gas industry pays more and more attention to it. Domestically selected products have not yet formed a certain trend, imported, joint venture, domestically produced, good and difficult to divide, the choice should be cautious. The RAQ series gas emergency shut-off valve is integrated with the filter. It has a novel and compact structure and high sensitivity. It can quickly cut off the regulator air supply at the set overpressure (300mm/H2O) and loss of pressure (180mm/H2O). User security.
Nine, gas emergency shut-off valve
In the case of gas leaks or other disasters in gas boilers, gas air conditioners, and gas equipment, the emergency shut-off valve quickly cuts off the gas source to prevent the disaster from expanding. At present, gas emergency shut-off valves have not been popularized in China. With the enhancement of environmental awareness and safety awareness, as well as the development of gas industry, gas emergency shut-off valves will surely receive people's attention. The gas emergency shut-off valve is a valve that guarantees the safety of the safety. It is connected with the automatic monitoring equipment and executes the valve closing command. Therefore, the gas emergency shut-off valve is an electric valve. According to the existing data, there are two types of valves, one is electromagnetic. Valves, one type is electric valves. Due to the high requirements of the gas emergency shut-off valve, the main ones are fast, sealed, small flow resistance, and safe caliber. The existing solenoid valves and electric valves have certain defects and cannot meet all the requirements.
Ten, gas check valve
Compressors in gas storage stations often need to be equipped with check valves to prevent gas from flowing back into the compressor. The water check valve has been eliminated in the gas industry. The main disadvantage of the general gas check valve is that the valve plate vibrates with the reciprocating motion of the compressor. The collision with the valve body makes a loud noise, which easily damages the valve plate. The second is the seal. Poor sex. The R-series gas check valve better solves these problems. The sealing of the series of check valves is changed from 90 degrees of other check valves to 75 degrees, which makes the valve plate form a natural pressure to the valve seat, and the outer structure of the valve plate plus the adjustable balance hammer solves the problem of sound; Sealing and reforming with PTFE has improved the sealing performance and eliminated the “return air” phenomenon. The R-type gas check valve has been in use for more than ten years, and the effect is very good.