Application scope and technical requirements of power station valves (3)

Application scope and technical requirements of power station valves (3)

Valve is an important part of large complete set of equipment, mainly used for cutting off, throttling, regulating pressure and changing flow direction of medium (material, water, steam, air and oil, etc.) in process pipeline. The quality of the valve directly affects the normal production of these devices, safe operation and environmental pollution, and plays a crucial role. Valve varieties and specifications are many, mainly gate valve, globe valve, check valve, ball valve, safety valve, pressure reducing valve, trap valve, butterfly valve and special purpose valve, wide use, large dosage. According to incomplete statistics and rough estimation, in a large complete set of equipment, the valve investment accounts for about 3% – 5% of the total investment in equipment.
(l) Valve manufacturer and production situation
The country at the county level above the management of valve enterprises about 180, including 19 key backbone enterprises, there are a certain scale of towns and individual enterprises more than 2000, small individual manufacturers difficult to statistics, township enterprises and individual manufacturers are distributed in Jiangsu and Zhejiang and central Plains area. In the valve industry, state-owned large and medium-sized enterprises, especially backbone enterprises, still have a great advantage in the valve manufacturing level and technical force. Some of these manufacturers have used resin sand line modeling, the main components of the valve in CNC machine tools, automatic lines or combination machine tools processing, sealing surface with equal separation from spray welding technology, valve design application CAD technology, three-dimensional solid modeling. Advanced technology has promoted the improvement of valve production level and product quality. But most valve manufacturers casting smelting equipment old, mainly manual modeling, machining for general machine tools and single tool cutting, detection equipment is not perfect or do not meet the standard. In recent years, some small and medium-sized valve manufacturers from strengthening the management of manpower, laying the foundation, equipment and grasp technical reform, production technology level gradually improved, product grade, grasp product quality, grasp the market, considerable economic benefits, with large or backbone enterprises to contend with the potential, its strength and development prospects can not be underestimated.
(2) Product level
Through the implementation of national standards, technology transfer, strengthening the test and detection means, the old product transformation and improve the level of design and process, level of valve products in our country has greatly improved in nearly 20 years, varieties of specifications, especially in hard seal butterfly valve, flat gate valve and hard seal ball valve on the categories and products increased faster (14 kinds of valve existing nearly 2000 series, More than 12,000 specifications). Among them, the volume of wide range of ordinary valves basically reached the level of the 1980s abroad, these valves in the product structure and material and other aspects of the valve produced abroad in recent years are similar, can be produced according to the standard of foreign requirements, but in the product quality is not stable enough, there is a certain gap with developed countries. But in some special valves, such as automatic control valve, hard seal ball valve, * * small flow valve, ash slag valve, the main steam isolation valve and stabilizer relief valve, etc.), high parameter valve (such as using the temperature higher than 700 ℃, caliber than lm ball valve), valve materials (hydrogen sulfide resistant steel material, urea and carbon fiber composite materials), and the gap with foreign valve actuator, etc Larger, variety shortage, should be through the introduction of technology (including the introduction of the valve reuse design) and technical breakthroughs gradually to solve. Valves, domestic supporting capacity can basically meet the 300000 t/a ethylene, 300000 t/a ammonia, urea, 60000 t, 520000 t/a of 80000 t/a/a high-pressure polyethylene, polypropylene, 60000 t/a ethylene glycol, 80000 t/a vinyl chloride, 50000 t/a propylene holt, 30000 t/a, acetaldehyde, 45000 t/a, 2.5 million t/a refinery, 3 butadiene 10,000 m3 / h air separation, 30MW thermal power station, 30MW nuclear power plant and long-distance transmission pipeline and other devices. The scale of large complete sets of equipment in foreign countries is expanding, promoting the level of valve matching with it. There is also such a development trend in China, but there is a big gap in supporting capacity compared with developed countries, mainly reflected in special valves, high parameter valves, control systems and driving devices.
Application scope and technical requirements of power station valves (III) Product model preparation method shall follow the provisions of JB/T4018. When the shell is WCB and WC1, WC6 and WC9 materials, the valve product model shall be compiled according to the method stipulated in JB/T4018 on carbon steel and cr al-V alloy steel respectively. Door signage and identification of paint proposal JB/T 106. For the body made of WCB, the identification and painting shall refer to the provisions of carbon steel materials; For valve bodies made of WC1, WC6, WC9, the identification coating shall refer to the provisions of alloy steel materials. Change of paint color is allowed at buyer’s request.
Connection: Application scope and technical requirements of power station valves (II)
8 Marking, packing, storage and transportation
8.1 mark
8.1.1 The compiling method of product model shall follow the provisions of JB/T4018. When the shell is WCB and WC1, WC6 and WC9 materials, the valve product model shall be compiled according to the method stipulated in JB/T4018 on carbon steel and cr al-V alloy steel respectively.
8.1.2 When the valve body is WCB, WC1, WC6, WC9 material, its brand number can be marked on the valve body.
8.1.3 Metal nameplates shall be installed on qualified valve products, and the binding position and size of nameplates shall be in accordance with the design drawings. Please refer to Appendix F for the contents of the nameplate
8.1.4 The important parts and pressure welds that pass the inspection shall be numbered or marked directly, and the marks shall be marked in the area with the lowest stress, especially to avoid the stress concentration zone, shape mutation and welding heat affected zone, which shall not hinder the judgment of the results of nondestructive testing.
8.1.5 Valve marking and identification painting Proposal JB/T 106. For the body made of WCB, the identification and painting shall refer to the provisions of carbon steel materials; For valve bodies made of WC1, WC6, WC9, the identification coating shall refer to the provisions of alloy steel materials. Change of paint color is allowed at buyer’s request. Other marks shall be executed according to relevant standards.
8.2 the packing
8.2.1 Before packaging, the valve should be painted in accordance with 8.1.5, and the parts not painted or the processed surface without rust layer should be coated with anti-rust oil.
8.2.2 The sealing surface, welded end, threaded end and the inner cavity of the valve on both ends of the flange should be protected by plugs or cover plates, and should be easy to assemble and disassemble.
8.2.3 The valve products shall be packed and shipped according to the packing list: The valves with large volume can be packed naked according to the order requirements, but it shall ensure that they will not be damaged during transportation.
8.3 keep
Valve products should be kept in a dry, ventilated room and piled up neatly as required. Open storage or stacking of products is not allowed.
8.4 transportation
8.4.1 During transportation, the valve disc shall be closed and the check valve disc shall be fixed; The plug valve should be in the unscrew position; The weight of the lever valve shall be removed from the lever, placed separately, and the lever fixed. The side flange or branch pipe welding groove at both ends of the valve channel is blocked with cover plate or plug to prevent dirt and sewage intrusion.
8.4.2 The exposed part of the stem shall be protected.
9 File Delivery
The delivery documents include product certificate, product packing list, and product installation and operation instructions. The basic contents are shown in Appendix G, H and I respectively
Appendix A
(Informative Appendix)
order
A.1 The basic order requirements guide is provided to the Buyer in Table A.1.
Table A.1 Basic order requirements
A.2 Table A.2 provides further instructions to buyers for specific ordering requirements for different types of valves.
Table A.2 Special order requirements
Appendix B
(Normative Appendix)
Pressure – temperature scale
B.1 Table B.1~ B.17 shows that the shell material is 20.25. Zg200-400. Zg230-450.15crmo.zg20crmo.12crmo v. 15Cr1 Molv.zG20CrMov.zG15Cr1Mo1v.1Cr5Mo. ZG1Cr5Mo. 1Cr18Ni9Ti and ZG1Cr18Ni9Ti valves, Its nominal pressure is 0.1 Mpa.0.25 Mpa.0.4 Mpa.0.6 Mpa.1.0 Mpa.1.6 mpa.2.5 Mpa.4.0 Mpa.6.3 Mpa.10.0 Mpa.16.0 Mpa.20.0 MPa. Pressure to temperature at 25.0 Mpa.32.0 Mpa.42.0 Mpa.50.0 Mpa.63.0 MPa.
B.2 Tables B.18 to B.21 show the pressure-temperature class values of valves with shell material WCB.WC1.WC6.WC9 for pound class 150.300.600.900.1500.2000.2500.3500.4500 respectively.