You need to set up the handwheel institutions pneumatic cut-off valve?

Pneumatic cut-off valve pneumatic cut-off valve is we often say, is also one of the automatic actuator, because of its strong function, good cutting effect, small flow resistance characteristics and was deeply loved by the masses, thus is widely used in petroleum, metallurgy, electricity, chemical industry and related industries. But a lot of people and have a question, is whether to cut off the valve need to set up the handwheel institutions? Small make up take you to discuss this problem. What is the function of pneumatic cut-off valve set the handwheel institutions? 1. When the source signal or electrical failure, or when the main components of the actuator ( Such as the diaphragm, spring, sealing parts and transmission parts, etc. ) Damage to automatically instead of manual operation, can use the handwheel institutions continue to maintain the pneumatic control valve regulating function. 2. The handwheel institutions can also be used as a pneumatic control valve stroke limiter. （ Limit function) 3. The handwheel institutions can improve the reliability of pneumatic control valve operation. Pneumatic control valve, such as adding bypass, the investment cost more, covers an area of big, when the diameter is larger or more expensive when using precious metals. Using the handwheel organisations in investment costs and covers an area of consideration, it is cheaper. Pneumatic cut-off valve related standards opponent wheel mechanism of claim 1. Specification for design of automation instrument selection HG/T 20507 - 201411. 9. 7 the handwheel institutions set shall meet the following requirements: 1 not bypass control valve, should be set the handwheel. 2 process safety interlock control valve for emergency cut-off valve, should be not installed the handwheel. 3 the handwheel should not be used for mechanical limit of the valve. 2. Specification for design of petrochemical industry automation instrument selection SH/T 3005 - 201610. 1. 12 the selection of pneumatic control valve accessories shall meet the following requirements: b) The following situation appropriate USES the handwheel institutions: 1) Not set cut-off valve and bypass valve pneumatic control valve; 2) The handwheel cannot be applied to the valve mechanical limit, unless there is a special occasion, other methods are not applicable to mechanical limit; 3) Special pneumatic regulator is 10. 3. 6. 12 of pneumatic actuators, the handwheel selection shall meet the following requirements: a) The handwheel should be installed side model, unless actuators have special requirements; b） The handwheel manual and automatic location should have clear identification, automatic position should be with a locking mechanism; c) The handwheel must be able to realize under the condition of no load power and valve design control actuators; d） Valve open/close operation direction shall be clearly marked on the handwheel, the handwheel shall not be used as a mechanical stop. 10. 3. 7. 10 electric actuators of the handwheel as a standard configuration, the design of clutch mechanism, should ensure that the motor operation takes precedence over the handwheel operation, no matter when, when motor starts, the handwheel operation should be automatic release. 3. The petrochemical industry guidelines for the emergency shutdown and safety interlocking system design SHB - Z06 - 19996. 2. Five safety related to the function of the control valve should not set the scene manually ( Should take safety reset function) You need to set up the handwheel institutions pneumatic cut-off valve? Cut-off valve is set the handwheel, no accurate answers, mainly due to different application scenarios, which should have a trade-off relationship. From HG/T20507-1 The requirement of 2014, primarily with interlocking as the center, to avoid the design of hand wheel impact interlocking action of execution. 2 sh / T3005 - 2016 there is no clear said whether you need to set up, but puts forward some basic constraint conditions. 3 in total, the cut-off valve associated with safety interlock should not set the handwheel. For other do not participate in safety interlock of the cut-off valve, from the Angle of process, according to the importance of process control, at the same time not bypass, and fault, the valve controllable in a limited period of time not to paralyze the production situation, can add the handwheel. This kind of situation, considering that can occur during normal operation of the workers wrong operation, close the valve manually, etc. , can consider to increase the corresponding management measures, such as wheel lock or the handwheel to dismantle, etc.