What is the difference between globe valve and gate valve

by:AIRWOLF     2020-05-20
Gate and globe valves is compared, its main advantage is that fluid flow resistance is small, the flow resistance coefficient of ordinary gate valves is about 0. 08 ~ 0. 12 and the drag coefficient is about 3 normal globe valves. Five to four. 5. Open the closing force is small, medium to two direction. Defect is complex, highly size is larger, sealing surface is easy to wear. Cut-off valve sealing surface, the force must be administered to seal valve in the closed, in the same diameter, working pressure, and the same drive, the cut-off valve drive torque for gate 2. 5 to 3. 5 times. This agency in the torque control for electric valve adjustment, should pay attention. Working principle, cut-off valve is rising stem type, hand wheel rotation and upward movement along with the valve stem. Gate valve is a hand wheel rotation, stem do upward movement. Flow, gate requires full open, globe isn't. Gate no direction of import and export requirements, globe valve has the import and export! From the appearance than cut-off valve gate valve short and tall, especially rising stem valves need higher height space. Gate valve sealing surface have certain self sealing ability, it's by medium pressure valve core and valve seat sealing surface tightly contact, to not leak tight. Wedge gate valve core slope is commonly 3 ~ 6 degrees, when the temperature changes forced shut down too much or larger valve core is easily jammed. So, high temperature and high pressure wedge gate valve, in structure adopted some measures to prevent valve core card dead. Gate valve in the opening and closing of valve core and valve seat sealing surface contact and friction each other all the time, thus sealing surface wear and tear, especially when the valve is in nearly closed state, pressure difference is very big, before and after the valve core sealing surface wear is more severe. Globe valve sealing surface, only to touch each other when fully closed, closed the valve core and sealing surface relative slippage is small, and sealing surface wear is small. And stop valve sealing surface wear, majority is because the valve core and sealing surface before have sundry, or imprecise is due to the closed position, cause of high speed scouring caused by. Globe valve when installed, medium can be from the bottom of the valve core into and from above into one of two ways. Medium enters from the bottom of the valve core has the advantage of packing when the valve closes, no pressure can prolong the service life of the packing, and before the valve under the condition of pipeline pressure, to replace the packing work. Medium from the bottom of the valve core to disadvantage is that the valve drive torque is bigger, 1 above is about to enter. 05 ~ 1. 8 times, stem by the axial force is big, the valve stem is easy to bend. Therefore, medium to enter from below, generally applies only to small manual stop valve, with the valve closed medium the force acting on the valve core is not more than 350 kg. Electric valve is generally adopts medium access from above. Medium entering way from above shortcomings just as opposed to enter below. Globe valve and gate valve compared with advantages of simple structure, good sealing performance, convenient manufacture and maintenance; Defect is liquid resistance is big, big opening and closing force. Gate and globe valves are fully open type valves fitted, as cut off or connect medium, should not be used as a control valve. Globe valve and gate valve application scope is determined according to its characteristics. In smaller channels, when requirements better shut off seal, with stop valve; In the steam pipe and large diameter of water pipe, due to the fluid resistance is small, the gate valve. Electric valves at http://www. dazkfy。 com
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