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Eccentric hemisphere valve technical requirements and device introduction
First, the eccentric hemispherical valve technical requirements (1) Eccentric hemisphere valve by the valve body, eccentric shaft, valve cover, ball crown, bushings, valve seat and other major components, through the eccentric shaft rotation 90 ° to achieve the valve opening and closing, Play the role of cutting off the media. (2) Connection form with pipe is flange connection, flange connection size and structure length should meet the requirements of the bidding documents. (3) eccentric hemisphere valve to ensure that the valve in the opening or closing process, the valve seat and the ball without friction, eccentric hemispherical valve with eccentric crankshaft, making the centerline of the ball crown and the valve runner centerline deviate from an eccentricity. When the valve is opened, the crankshaft turns a very small angle, the ball will leave the valve seat, the ball and the seat no longer contact; the other hand, the valve is closed in the process, only the moment of closure, the ball and the seat contact. (4) eccentric hemisphere valve with a body structure, in the maintenance process, without removing from the pipeline, just remove the valve cover bolts, remove the valve cover, which can remove the eccentric shaft, which ensures that the valve can Online repair. (5) eccentric hemisphere valve should be opened in the flow to ensure complete flow of head loss at run time. Ball using semicircular channels, with good flow and linearity adjustment performance, and impurities will not be deposited in the body cavity. (6) Eccentric hemispherical valve should have sufficient strength, the eccentric crankshaft with a fixed ball structure, without any vibration at high flow rate, the shell test according to the national standard GB13927-1992 implementation. (7) eccentric hemisphere valve does not allow leakage, the upper and lower shaft end should be sealed with at least 2 O-ring. (8) Eccentric hemisphere valve with cutting function, the closure of the media can be debris (branches, textile bags, etc.) cut off to ensure the normal valve opening and closing. (9) eccentric hemispherical valve surface treatment: first shot blasting, then acid and alkali phosphating, to be dry immediately after brushing anti-rust paint, then spray epoxy paint, according to national standards: "JB / T106-2004 Valve logo and paint "implementation. (10) Eccentric hemisphere valve casting using advanced mechanical modeling, resin sand casting process casting, should have a good appearance quality, castings are interchangeable. (11) manual uploading double sealed eccentric hemispherical valve transmission worm gear, the operation should be convenient, flexible, safe and reliable. (12) The operation is safe and reliable, and for the influence of media scaling or particles may have on the valve opening and closing torque, the design torque of stem and the safety factor of the actuator must be increased with the safety factor not less than 2. (13) casting surface should have a good surface paint, paint the buyer to determine the color. Second, the eccentric hemispherical valve structure and material requirements 1, eccentric hemisphere valve design, manufacturing should be consistent with the provisions of GB / EN / ISO standards, or equivalent standards. 2, eccentric hemispherical valve structure type eccentric hemisphere valve with a double seal eccentric hemispherical valve structure. Eccentric hemisphere valve should be eccentric design to ensure that the valve in the opening or closing process, the valve seat and the ball without friction between each other to extend the service life of the valve. Eccentric crankshaft rotation center and body center must have a certain eccentricity. Eccentric hemisphere valve with underground valve well installation, downhole operation, hand wheel side, the transmission is stable and reliable, set the support point according to the installation height. 3, eccentric hemisphere valve seal type eccentric hemisphere valve with metal and non-metallic two seals, and requires self-sealing. Non-metallic seal with wear-resistant, cold rubber, valve should be diversion effect. Seal test according to the national standard GB13927-1992 implementation. Eccentric hemisphere valve does not allow leakage, the upper and lower shaft ends should be sealed with at least 2 O-ring 4, valve body connection type and length requirements eccentric hemispherical valve end should be set flange, flange connection size implementation of the overall cast iron Pipe flange GB / T 17241.6-1998 standards, working pressure PN1.0MPa. 5, the valve body, ball, bonnet, pressure ring and transmission housing Body, ball, bonnet, pressure ring and transmission housing is ductile iron, the structure of a single eccentric, material standards according to GB QT 450-10 standard carried out. 6. The minimum shaft diameter of the spherical cap, valve shaft and sleeve shaft shall be in accordance with the provisions of GB / AWWA / EN and at the same time shall meet the requirements of the project. The bidder shall design the diameter of the valve shaft to ensure its use according to the specific conditions of the project. The crown, shaft and sleeve are stainless steel. The key shaft is connected to the drive. Extruding or rubbing the connection can not be accepted. Valve shaft should be dry shaft design, the valve shaft is completely O-ring (both ends have two O-rings) and bearing coating to ensure that the bearing and stem gap does not produce any corrosion, to ensure long-term reliable operation, maintenance-free . Valve shaft end and drive the implementation of GB / T12223-1989 standards. 7, inside and outside the valve seat, the valve seat material is stainless steel, stainless steel 3Cr13 (quenching) standards or higher standards. All contact with the media used as fasteners should be made of stainless steel. Stainless steel complies with A2-70 or higher standards. 8, eccentric hemisphere valve installation type eccentric hemisphere valve with vertical installation. Valve body should be hoisted rings, in order to facilitate the overall hemisphere eccentric hoisting. 9, epoxy lining and anti-corrosion coating A, in line with the People's Republic of China National Health Standard GB / T17219, unless otherwise specified. B, Eccentric hemisphere valve cavity and eccentric shaft corrosion should be used in high temperature and electrostatic treatment of epoxy resin coating (ie, spray treatment), the coating thickness should be greater than 250μm, and passed the national provincial and ministerial level and above qualified units Certification, and need to provide certification. C, eccentric hemisphere valve appearance coating: the outer surface of the valve body using high temperature and electrostatic treatment process epoxy coating (ie, spray treatment), electrostatic spraying epoxy resin, the thickness of not less than 250μm. After the equipment is installed, the damage to the surface of its paint shall be repaired in a manner approved by the bidder's representative. Repair paint with the same color as the original paint. 10, the number of effective valve opening and closing not less than 50,000 times. 11, eccentric hemisphere valve accessories (1) code plate equipment nameplate should be printed, engraved on 1mm thick stainless steel plate, the minimum size of 120mm × 60mm, and fixed in the device easy to see location, each Nameplate engraved with the valve number, the number should be consistent with the technical specifications of the valve table number, the card with a fixed ring attached to the console, to ensure that the ring does not move. Specific valve signs according to "common valve logo" ISO5209 or GB12220 standards. (2) The successful bidder shall submit the main data such as the valve structure dimension required by the technical specification, the maximum torque requested by the valve and the weight of the valve, and the list of major equipment to the tenderee for examination and confirmation before the contract is signed. 12, valve equipment reliability and durability (1) the valve operating mechanism should have sufficient torque and stiffness to ensure the stability of the valve is opened and closed, and open and close under unbalanced pressure. (2) completely sealed without leakage. (3) Operation overhaul intervals of not less than 30,000 hours. (4) Valve body, valve shaft, gearbox and other major components of the service life of not less than 30 years. Third, the eccentric hemispherical valve actuator 1, Overview Eccentric hemispherical valve worm gear drive, driven by the national standard "GB / T12223-2005 part of the rotary valve drive connection" implementation, the drive operation should be convenient and flexible, Safe and reliable, the operating torque should not be higher than the national standard, at the same time there must be significant opening instructions and mechanical limit adjustment agencies. Transmission including gearbox, hand wheel and other ancillary facilities. All force components can withstand more than 3 times the rated torque (opening and closing the valve when the force is too large) without any damage, but also has the light open and flexible, open a small number of laps, will not cause the wrong direction of operation. To ensure that the valve plate can stay in any stable position in the middle of the effect. Drive has a good grease lubrication, maintenance-free. Applicable working temperature: -40 ℃ ~ 40 ℃. 2, electric valve drive electric eccentric hemispherical valve drive motor driven, motor action easy, flexible, safe and reliable. Motorized electric hemisphere hemisphere electric device includes special motor, deceleration worm, mechanical limit adjustment mechanism, travel control mechanism, torque control mechanism, hand electric switching mechanism and opening degree indicating mechanism, all electrical components are all well-known brands. Dedicated motor working environment: ambient temperature -20 ℃ ~ 60 ℃, relative humidity ≤ 90%, field work power AC380 ± 15% and control power AC220 ± 15%, 50Hz ± 2%, and overheating protection, the motor can Open or close the valve under unbalanced water pressure, the protection class is IP55, the working medium does not contain corrosive, flammable, explosive and so on. Electrical device side of the mechanical limit adjustment mechanism, the switch position in the factory has been adjusted in place, generally do not need to adjust, as in the use of the valve after a period of leakage, just loosen the lock nut, fine tune the limit bolt Then tight nut can be tight, the adjustment is very convenient and fast.