Medium carbon steel casting off valve J41H-25C

As of the cut-off valve selection principles valve is one of the most widely used valves, ball valves and butterfly valves with the development, application cut-off valve is substituted for a portion of the occasion, but the characteristics of the cross-sectional view of the valve itself, ball valves, butterfly valves not a substitute for, the selection principle is: (1) should be on the high temperature, high pressure tubing, or media device selection valve. Fire power plants, nuclear power plants, petrochemical system of high temperature, high pressure piping selection of cut-off valve is appropriate. (2) pipeline pipeline convection resistance requirements lax. That is not the place to consider the pressure loss. (3) Small valves shut-off valve can be used, such as a needle valve, instrument valve, sampling valve, pressure gauge valve. (4) flow regulation or pressure regulation, but accuracy is not required to adjust and conduit diameter and relatively small, such as the nominal diameter of the pipeline ≤50mm, should use the cut-off valve or throttle. (5) Synthesis of industrial production of small and large chemical fertilizer fertilizer should use nominal pressure PN160 nominal pressure PN320 nominal pressure 16MPa or 32MPa high-pressure or high angle-type valve throttle angle. (6) Bayer alumina production desilication plant, pipeline easy coking, should use split-body, removable seat, carbide Sealing DC DC-type valve or throttle . (7) of city construction of water supply, heating engineering, nominal diameter smaller pipeline, the choice of cut-off valve, balance valve or piston valve, as it is less than the nominal 150mm pipeline. 6 valve shut-off valve which category? How the correct choice? Case of closed type valve shut-off valve, cut off from its primary role in the pipeline. Cut-off valve is a valve used in a multi, but also as the most appropriate form of throttling. Because it has a good regulation performance, and compared with other structural type of valve, globe valve seat surrounding the distribution of erosion due to the wear and tear caused by the uniform. Cut-off valve is mandatory sealed valve, so when you close must apply pressure to the valve, so that the two sealing surface does not leak. Since the cutoff valve sealing force and media pressure is on the same axis, but in the opposite direction, the sealing force is not only enlarged, but also to overcome the pressure of the media, thus sealing force is much greater than the valve shut-off valve required. Special attention should be in the selection of the cut-off valve, the shut-off valve with a flat-seal can not be used filthy media or media containing solids. In these media, the use of conical sealing surface seal is more appropriate. Typically, the throttle adjustment, high pressure piping systems is recommended to use the cut-off valve; the need to double-regulator, small light structural requirements, length of the structure without strict requirements, low pressure cut-off (pressure difference), high cloud the medium can be selected cutoff valve; in the mud, in the medium containing solid particles, abrasion, Path necking, require fast action (ie 1/4 turn open and close), the manipulation force-hour day do not use the cut-off valve; requiring good sealing performance, high-pressure cutoff (large pressure), low noise, cavitation and vaporization, a small amount of leakage into the atmosphere, abrasive media, when using dedicated cryogenic design structure of the cut-off valve. Shut-off valve is also an important feature is that the bellows stem seal can be used to replace the packing, constitute bellows globe valves. Bellows valve for flammable, explosive, toxic, very pure media, but also to meet the requirements of the vacuum system. However, the cut-off valve also has its drawbacks, mainly caused by the internal shape of the body. In the cutoff valve chamber, the medium flow direction from the horizontal line is changed upward or downward vertical flow, and then flows into the horizontal direction, and therefore a pressure loss, especially in the hydraulic means. This pressure loss should be adequate attention. Cut-off valve is extremely widespread use, but because of the larger opening and closing moments, the structural length is longer, usually nominal diameter are limited DN250mm less. 7 knowledge shutoff valve shut-off valve is closed parts (valve) moves along the centerline of the valve seat. According to this mobile form of valve and valve seat port change is associated with the valve stroke is proportional. As such the valve stem to open or close the relatively short trip, but also have very reliable cutting function, but also because the trip is proportional change in the seat and the valve port valve is very suitable for flow regulation. Therefore, this type of valve is suitable for cut or regulation and throttle use. Its selection principles are: 1, high temperature, high pressure piping or equipment should be selected medium cut-off valve. Fire power plants, nuclear power plants, petrochemical system of high-temperature, high-pressure pipeline. 2, pipeline convection resistance strict requirements of the pipeline. That is not the place to consider the pressure loss. 3, the choice of a small needle valves, instrumentation valves, sampling valves, pressure gauge valve. 4, flow regulation or pressure regulation, but accuracy is not required to adjust and conduit diameter and relatively small, such as Nominal by ≤50mm the pipeline, should be selected. 5, synthetic industrial production of small and large chemical fertilizer fertilizer should use nominal pressure PN160 nominal pressure PN320 nominal pressure 16MPa or 32MPa high-pressure or high angle-type valve throttle angle. 6, Bayer alumina production Desilication workshop, pipeline easy to coke, easy selection of the divided body, can place the seat, carbide Sealing DC or DC-type valve throttle. 7, the urban construction of water supply, heating engineering, Nominal by smaller pipeline, the choice of cut-off, balancing valve or piston valve, such as Nominal by less than 150mm in the pipeline. The most obvious advantages are: the opening and closing process, because the valve body in the friction between the sealing surface than the gate is small, and thus wear. Open seat height is typically only 1/4 channel diameter, so much smaller than the gate. Usually in the valve body and the valve has only one sealing surface, and thus the manufacturing process is better, ease of maintenance. Nominal or pressure level: PN1.0-16.0MPa, ANSI CLASS 150-900, JIS10-20K nominal diameter or caliber: DN10 ~ 500, NPS 1/2 ~ 36 "; Connection: flange, welding, thread and other applicable temperature: -196 ℃ ~ 700 ℃ Drive: pneumatic, electric, hydraulic, gas-liquid interaction, body material: WCB, ZG1Cr18Ni9Ti, ZG1Cr18Ni12Mo2Ti, CF8 (304), CF3 (304L), CF8M (316), CF3M (316L), Ti. use different materials, can be separately applied to water, steam, oil, nitric acid, acetic acid, oxidizing medium, urea and other media.