With more than 30 years of casting history, Wenzhou Longzhu Industrial Co., Ltd. has a large number of experienced casting engineers and technicians. We can produce castings of various sizes, shapes and materials according to the drawings provided by customers, especially in the field of valve castings. Cooperate with Fortune 500 companies for many years.
GS-C251.0619,WCB.WCC,LCB,LCC,LC3,4C,4D,WC6,C5,C12, C12A,CA15，CF3,CF8(-196’C),CF3M,CF8M,CF8C,CD4MCu,CK3MC uN,ZG200-400,ZG230-450,ZG270-500,2G40Cr1,ZG20CrM0.2G15C r1Mo1V,ZG35Cr1MO.ZG16CrMOG(1Cr5Mo),ZG1Cr13,ZGOCr18Ni9 Ti.5A.KmTB Cr26.4A
Resin sand casting, etc.
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The shut-off valve, also known as the gate valve, is a forced-sealed valve, so when the valve is closed, pressure must be applied to the valve flap to force the sealing surface to not leak. When the medium enters the valve from under the valve flap, the resistance to be overcome by the operating force is the friction between the stem and the packing and the thrust generated by the pressure of the medium. The force of closing the valve is greater than the force of opening the valve, so the valve stem The diameter of the stem should be large, otherwise the valve stem top bend will occur. There are three types according to the connection method: flange connection, thread connection, and welding connection. After the self-sealing valve appears, the medium flow direction of the shut-off valve is changed into the valve cavity from above the valve flap. At this time, under the action of the medium pressure, the force of closing the valve is small, and the force of opening the valve is large, and the diameter of the valve stem can be correspondingly Reduced. At the same time, this type of valve is also tight under the action of the medium. China's valve "three-way to give" has stipulated that the flow of the stop valve, all from top to bottom. When the shut-off valve is opened, the opening height of the valve flap is 25% to 30% of the nominal diameter. The flow rate has reached the maximum, indicating that the valve has reached the fully open position. Therefore, the full open position of the shutoff valve should be determined by the stroke of the valve flap.
(1) The structure of the stop valve is simpler than the gate valve, and it is convenient to manufacture and maintain.
(2) The sealing surface is not easy to be worn and scratched, and the sealing property is good. There is no relative sliding between the valve flap and the sealing surface of the valve body when opening and closing, so the wear and the scratch are not serious, the sealing performance is good, and the service life is long.
(3) When opening and closing, the valve flap stroke is small, so the height of the shut-off valve is smaller than that of the gate valve, but the structure length is longer than the gate valve.
(4) The opening and closing torque is large, the opening and closing is more laborious, and the opening and closing time is the principal.
(5) The fluid resistance is large, because the medium passage in the valve body is tortuous, the fluid resistance is large, and the power consumption is large.