| Media: | Steam Oil Water |
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| Certification: | CCC, RoHS, ISO, CE |
| Temperature: | High Temperature |
| Connection: | Flange |
| Valve Seat: | Single-Seat |
| Structure: | Lever |
| Customization: |
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A brief introduction | Introduction of special pressure reducing valve in coal mine Coal mine special pressure reducing valve by the main valve and pilot valve composed of two parts. The main valve is mainly composed of the seat, the main valve disc, the piston, the spring and other parts. The pilot valve is mainly composed of the seat, valve disc, diaphragm, spring, adjusting spring and other parts. By adjusting the spring pressure to set the outlet pressure, using the diaphragm to sense the change of outlet pressure, through the pilot valve opening and closing drive piston to adjust the size of the main valve throttling part of the flow area, to achieve pressure reduction and pressure regulation function. There are generally two ways to decompress the fire sprinkler pipe in coal mine: one is to use the depressurization pool, and the other is to use the pressure reducing valve to decompress. But over the years due to the development of domestic pressure reducing valve products, most of the development for construction projects, and through the industry identification, really can make designers and users at ease with the choice of domestic mining pressure reducing valve is almost blank, if the use of similar foreign products from the design and selection to user orders, construction and installation, maintenance services, there are many inconveniences. Therefore, in the coal mine fire sprinkler pipe generally used is still the depressurization of the depressurization pool. Zhejiang Shangou valve main valves are: pressure reducing valve (gas pressure reducing valve, adjustable pressure reducing valve, water pressure reducing valve, steam pressure reducing valve in recent years, our hospital in coal mine fire sprinkler pipe design encountered the following problems :(1) mine gas concentration is high, all electrical facilities in the mine must use explosion-proof type. Such as Huajin coking coal company Luliang company Shaqu mine, Jincheng Mining Bureau Sihe mine and other high gas mine using depressed-pressure pool its inlet electric valve and water level control device must be explosion-proof type; (2) The roadway is arranged along the coal seam, and there are ups and downs. For example, after the depressurization of the depressurization pool is used in the shaft of Sihe mine, the roadway from the bottom of the shaft to the mining area is on an uphill slope, and the pipeline after the depressurization needs to be pressurized to meet the requirements of water in the mining area. (4) In order to make the depressioning pool set in a suitable position, increase the length of the fire sprinkler pipe, such as Xiangshan mine, Hancheng Mining Bureau, the underground fire sprinkler pipe enters from the return air shaft, in order to meet the water pressure requirements of the roadway and mining area, the depressioning pool can not be set near the bottom of the well, it needs to be set in the inclined well, which increases the round-trip pipeline by more than 1000 meters. The above encountered several situations such as the use of pressure reducing valve decompression, it is simple and convenient, according to different pressure requirements at will on the main pipe, branch pipe set pressure reducing valve, so that the entire fire sprinkler pipeline is simple, flexible, water saving, power saving, and can greatly save infrastructure investment. In view of these circumstances, designers are eager to select a pressure reducing valve with excellent performance, reliable quality and adaptability to the national conditions to solve these problems. In April 1996, Shanghai Shenhong Valve Co., LTD., after extensive contact, reached a consensus, decided to jointly develop and develop mine proportional pressure reducing valve products to meet the needs of coal mine underground fire sprinkler pipe pressure reduction. The project was included in the Ministry of Coal industry 597 annual coal industry design and scientific research project plan 6, after the unremitting efforts of the subject group, has completed all the work, and passed the identification of the Ministry of Coal on June 15, 1998. Three, technical production requirements 1. General requirements 1) The design and design documents of the valve production should comply with the provisions of the relevant national standards, and be reviewed and approved by the prescribed procedures. 2) Nominal diameter according to GB/T1047-2005 "Pipeline components DN(nominal size) definition and selection" priority selection. 3) The nominal pressure series is preferentially selected according to GB/T1048-2005 "Definition and Selection of pipeline components PN(nominal pressure)", the digital unit behind the nominal pressure PN is (bar). 4) Pressure - temperature grade The pressure-temperature rating of the valve meets GB/T9124-2000 "Technical conditions for steel pipe flanges" The specified pressure is 6.4mpa, and the valve body should bear twice the pressure of the load for 20 minutes, and the temperature should reach the standard used by Party A -5ºC ~ 425ºC 5) The structure form and size of the flange comply with the provisions of GB/T9113-2000 "Integral steel pipe flange". 6) The mechanical workpiece should comply with the provisions of YB/T036.17 "Metallurgical equipment manufacturing general technical conditions for mechanical workpiece". 7) Heat treatment parts should comply with the provisions of YB/T036.16 "Metallurgical equipment manufacturing general Technical conditions for heat treatment parts"; 2. Material Body material selection WCB high carbon steel and chemical composition, mechanical properties should comply with YB/T036.3, GB/T700, GB/T699, GB/T3077 standards. The main component materials should be selected according to the use of temperature, working pressure, media and other factors. When the use temperature is -5ºC ~ 425ºC, the components in the valve should be selected heat-resistant steel. The valve stem material is stainless steel 2Cr13; The bolt adopts high strength bolt (10.9), and the hardness and strength are greater than the valve stem; The valve stem bushing material is bronze sleeve, its hardness and strength should not be greater than the valve stem, and under the condition of water immersion and valve stem, valve body does not form electrochemical corrosion. 3, casting requirements of the valve body 1) The surface of the inner and outer cavity of the valve body should be smooth and smooth, and the seam should be cleaned. 2) No sticky sand, no slag, no cracks and defects are required. 3) No obvious porosity, sand hole, less meat and other defects. 4) Casting size tolerance in accordance with ± 1/2IT12 level execution. 5) Casting materials, molding methods, casting conditions, etc. comply with the provisions of JB/ZQ4000.5 "General Technical Requirements for Castings". 4. Sealing surface 1) The sealing surface of the valve seat is surfacing alloy steel, represented by "H". 2) The sealing surface of surfacing welding, the thickness of the surfacing layer after processing should not be less than 2mm, and the stress should be fully eliminated after surfacing. 3) The sealing surface of the seat, valve disc & valve ball must be ground, the flatness error is not less than the GB/T1184-1996 standard 5 precision provisions, the surface roughness should not be greater than Ra0.8μm. 4) The end faces of the two flanges of the valve body should be parallel to each other and perpendicular to the pipeline axis, and the parallelism and verticality error are stipulated by the GB/T1184-1996 standard K level accuracy. 5. Shaft end support and seal: According to the use of temperature, the bearing seat should meet the requirements of use, and the use of anti-wear oil graphite sealing filler. 6, size requirements 1) The dimensional tolerance of the flange includes the thickness of the flange and the outer diameter of the flange, the diameter of the sealing surface, the diameter of the center circle of the bolt hole, the chord distance of the two adjacent bolt holes, the chord distance of any two bolt holes, the diameter of the bolt hole, the coaxial tolerance of the center circle of the bolt hole and the machining sealing surface, etc. according to the provisions of GB/T9124-2000 "Technical Conditions for steel pipe Flanges". 2) The structural length tolerance of the valve is implemented according to the provisions of GB/T12221-2005 "Flange connection metal valve structure length" and the provisions of JB2205 pressure reducing valve structure length. 7, strength and safety requirements 1) The materials used for the seat, disc/ball, shaft and other components must meet the requirements of the corresponding working temperature strength and stiffness. 2) The valve body should be able to withstand the maximum pressure of the medium of 2 times the load, valve disc/ball should be able to withstand 1.5 times the load without deformation. Fifth, inspection and test 4, performance test 1, strength test: refer to GB/T13927 general valve pressure test. a. Before the test, it is not allowed to paint or use other anti-leakage coatings on the valves. If Party A requires to redo the test on the valves in stock of Party B that have been painted, it is not necessary to remove the coating and Party B shall bear the expenses b. Test procedure: Valve body round flange on both ends of the blind plate, add the gasket, press the packing gland, in order to maintain the test pressure. The disc and ball are partially open. Fill the body cavity with the test medium, gradually increase to the test pressure, and then check the housing. The shell pressure wall and the valve body shall not have visible leakage at each connection, and the valve body shall not have structural damage. If there are no special provisions, under the test pressure of the shell, the leakage of the packing is allowed, but when the test pressure is reduced to the seal test pressure, there should be no visible leakage. c. The test pressure is 1.5 times of the maximum allowable working pressure when the test pressure is 20ºC. 2) Sealing test: Close the valve in the way given in the design, close the high-pressure side of the valve, introduce the medium (water) and gradually pressure to the test pressure, the test pressure is 1.1 times the nominal pressure of the valve (or according to the seal pressure test given by Party A). If Party A has special requirements, it will be specified separately in the order contract. 4) The maximum duration of pressure test and seal test is 10 minutes |
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