Analysis of valve electric device selection method

Since the electric valve is a combination of the valve and the electric device, how to choose the electric device correctly when the valve is determined is an important factor that relates to whether the actual use can meet the engineering requirement. In selecting the motorized unit, consideration should be given not only to the aforementioned working environment, electrical control and general technical performance, but also comprehensive consideration of the overall technical performance of the motorized unit. 1, the output torque and speed of the electric device The output torque value is one of the important technical parameters of the electric device, which is also an important parameter that needs to be selected in use. It is not advisable if the output torque of the electric device used in assembling the electric valve is too large or too small. Because of the general situation, it is relatively accurate that the electric device manufacturer needs to test and adjust the output torque value when the product is shipped from the factory. If the use of excessive output torque margin, will make the electric valve has a great potential danger, in the event of control and protection failure will easily cause valve damage (stem bending, body rupture) phenomenon can easily lead to Pipeline accident. So the output torque margin is too large to choose is not desirable. If you can not open the valve in the actual work is the choice is unreasonable. On the output of the electric device to determine the speed, the valve on its opening and closing time is not strictly required, we should try to use a slower speed. Because of the unnecessary speed, the same torque requirements will increase the motor power, so that not only a waste of energy, improve project costs, but also make the electric device increases the size of the resulting waste of many. At present, the electric devices developed and developed by ourselves have a limited number of motor specifications (usually 2-3 specifications) designed and used in each frame number, and the speed ratio ranges of the gear pairs and the worm gear pairs in the main transmission are limited , So each frame number of torque sub-file and speed sub-file is not much. 2, the maximum allowable thrust of the electric device If the axial force of the valve is borne by the electric device (that is, the stem nut is in the electric device), its thrust value is not allowed to exceed the allowable value of the electric device. 3, the maximum number of turns of the stem nut In the selection of multi-turn valve electric device must be described when the valve working spindle nut maximum number of turns, so you can correctly select the electric device position indicator mechanism gear ratio to make the position Indicates sufficient accuracy to meet the valve opening and closing the valve during the observation of the degree, otherwise easy to create illusion, affecting the normal work. 4, the allowable value of stem diameter lifting rod valve selection electric device should pay attention to the diameter of the stem that allows it to pass, the stem diameter must be less than this value. In addition, multi-turn electric devices, the choice should also be made on the stem cover height requirements (with the valve pain path). Rotary rod valve without valve stem cover. 5, the valve and electric device connection Valve and electric device connection type and size should be consistent with national standards: GB / T12222-1989 multi-turn valve drive connection, GB / T12223-1989 part of the rotary valve drive connection. At present, some rotary valve electric devices have mechanical limit to prevent the valve position can not be judged, such valves and electric devices between the connection screw holes and keyway position of the strict requirements. More Keywords Search: Valve