How to Select Sanitary Butterfly Valve?
Control moment: control torque is the most important parameter to select valve electric device. The process of electric butterfly valve can be controlled by the size of the stroke, torque or axial thrust. Because the characteristics and usage rate of valve electric device depend on the type of valve, device case and valve position in pipeline or installation equipment deployment, electric sanitary butterfly valve device are to achieve valve program control, automatic control, and remote control. Therefore, selecting the accurate valve electric device to prevent the occurrence of overload symptoms (event torque is higher than control torque) is essential.
The torque of the electric device should be 1.2-1.5 times the most powerful moment of valve control.
Electric butterfly valve control thrust: the main engine layout of valve electric device has two kinds: one is not equipped with the deployment of a thrust disk. The torque is transferred to the output thrust through the stem nut in the thrust plate. Direct torque is lost; the other is setting up the equipment to deploy the thrust plate.
Output shaft rotation circle: the number of valve electric device output shaft rotation circle with the valve nominal diameter, valve stem pitch, thread head number related. H for valve opening height, we must calculate according to M=HZS (M is the total number of turns required for the electric device. S thread pitch for stem drive, Z is the number of threaded head of stem.)
Butterfly valve has the characteristics of simple structure, small volume, light weight, low material consumption, small device size, switching agility, 90-degree reciprocating reversal, small driving torque, etc. It is used to cut off, switch on, adjust the medium in the pipeline, with outstanding fluid control characteristics and sealing function.
The sanitary butterfly valve can transport the liquid stored at the pipeline. Under low pressure, excellent sealing can be achieved. Conditioning function is good.
The streamlined design of the butterfly plate makes the fluid resistance loss small. It can be said to be an energy saving commodity.
The valve stem is a through-rod structure, which has the outstanding inductive mechanical function, corrosion resistance and scratch resistance through tempering treatment. When the butterfly valve is opened and closed, the stem only rotates without lifting. The packing of the stem is not easy to be damaged and the seal is reliable. Fixed with the butterfly plate cone pin, the protruding end is designed to prevent the valve stem from falling out when accidental cracking occurs at the joint of the valve stem and the butterfly plate.
The connection method has flange connection, clip connection, butt welding connection, and lug coupling.
The driving methods include manual, worm gear drive, electric, pneumatic, hydraulic, electro-hydraulic linkage and other actuators, which can complete long-distance control and automatic operation.
1, opening and closing convenience, agile, labor-saving, small fluid resistance, can often operate.
2. Simple structure, small size, short construction length, small volume, lightweight, suitable for large-caliber valves.
3, can transport mud, at the mouth of the pipeline liquid storage at least.
4, low pressure, can achieve the outstanding seal.
5, conditioning function is good.
6, full opening valve seat effective flow area larger, less fluid resistance.
7. The opening and closing torque are small, because the effect of the medium on both sides of the rotating shaft butterfly plate is basically flat, and the direction of the torque is opposite, so the opening and closing is more labor-saving.
8, sealing surface materials generally choose rubber, plastic, so the low-pressure sealing function is good.
9, the device is convenient.
10. The operation is sensitive and labor-saving. Manual, electric, pneumatic and hydraulic methods can be selected.
1, The use scope of pressure and working temperature is small.
2, Poor sealing.
According to the construction method, butterfly valves actuator can be divided into offset plate type, vertical plate type, inclined plate type, and lever type. According to the sealing method, it can be two types: soft sealing type and hard sealing type. Rubber seals are generally used for soft sealing type, and metal rings are usually used for hard sealing.
According to the type of connection, sanitary butterfly valve can be divided into flange connection and clamp connection; according to the transmission method, it can be divided into manual, gear transmission, pneumatic, hydraulic and electric.