Z61h / y forged steel gate valve is a widely used valve
Z61h / y forged steel gate valve refers to the valve whose closing part (gate) moves along the vertical direction of the center line of the passage. The gate valve is mainly used for cutting off in the pipeline. Z61h / y forged steel gate valve is a widely used valve. It is generally used for cutting-off devices with diameter DN ≥ 500mm, and sometimes gate valve is also used for cutting-off devices with small diameter. As a low-level valve, gate valve is more common.
Z61h / y forged steel gate valve has three bonnet design forms. The first is the bolted bonnet. For the valve designed according to this design form, the valve body and bonnet are connected with bolts and nuts, and the spiral wound gasket (made of 316 clamp flexible graphite) is sealed. Metal ring connection can also be used when customers have special requirements. The second design form is the Welded Bonnet. For the valve in this design form, the valve body and bonnet are connected with threads and sealed by full welding. Full penetration connection can also be used when customers have special requirements. The third is the pressure self tightening bonnet. For the valve designed according to this design form, the valve body is threaded with the bonnet, and the internal pressure self sealing ring is sealed.
Z61h / y forged steel gate valves are all gate valves cast into castings with metal steel materials, collectively referred to as cast steel gate valves. Corresponding to z61h / y forged steel gate valve, cast iron gate valve, forged steel gate valve, malleable cast iron gate valve, cast copper gate valve, etc. The opening and closing part of the cast steel gate valve is the gate, and the movement direction of the gate is perpendicular to the fluid direction. The gate valve can only be fully opened and closed, not adjusted and throttled. The gate has two sealing surfaces. The most commonly used mode is that the two sealing surfaces of the gate valve form a wedge, and the wedge angle varies with the valve parameters. The gate of the wedge gate valve can be made into a whole, which is called a rigid gate; It can also be made into a ram that can produce slight deformation to improve its manufacturability and make up for the deviation of the angle of the sealing surface in the processing process. This kind of ram is called elastic ram.
Z61h / y forged steel gate valves are divided into carbon steel gate valves, stainless steel gate valves, low alloy steel gate valves (high temperature resistant chromium molybdenum steel belongs to this category), low temperature steel gate valves, etc.
There are various specific steel grades under various z61h / y forged steel gate valves, which are commonly used as follows:
1. The casting grades of carbon steel gate valves include: WCA, WCB, WCC, LCB, etc; Applicable temperature - 46 ℃ ~ 425 ℃.
2. Casting grades of stainless steel gate valves: 301 stainless steel, CF8 stainless steel (corresponding to forging 304 stainless steel), CF8M stainless steel (corresponding to forging 316 stainless steel), etc; Applicable temperature - 198 ℃ ~ 816 ℃.
3. Low alloy steel is divided into high-temperature alloy steel and high-strength low-alloy steel, among which high-temperature alloy steel is often called chromium molybdenum steel. Casting grades of chromium molybdenum steel gate valves: zg1cr5mo, zg15cr1mov, ZG20CrMoV, wc6, wc9, c12a, etc. Applicable temperature: 550 ℃ ~ 750 ℃.
Z61h / y forged steel gate valve is applicable to small-diameter pipelines with Class 150 ~ class 2500 and working temperature of - 29 ℃ ~ 425 ℃ (carbon steel) or - 29 ℃ ~ 500 ℃ (stainless steel). It is used to cut off or connect the medium in the pipeline. Different materials are selected and can be applied to water, steam, oil, nitric acid, acetic acid, oxidizing medium, urea and other media.
Structural features of z61h / y forged steel gate valve:
1. The fluid resistance of forged steel gate valve is small, and its resistance coefficient is equal to that of the pipe section with the same length.
2. Forged steel gate valve has the advantages of simple structure, small volume and light weight.
3. It is tight and reliable. At present, the gate valve has good sealing performance and has been widely used in vacuum system.
4. Convenient maintenance, simple structure of gate valve and convenient disassembly and replacement.
Z61h / y forged steel gate valve often ignores the pressure problem. During the grease injection operation, the grease injection pressure regularly changes from peak to valley in the semi free floating ball steam trap. The pressure is too low, the seal leaks or the safety valve fails, the pressure is too high, the valve manufacturer at the grease injection port is blocked, the grease in the seal is hardened, or the sealing ring is locked with the valve ball and valve plate. Usually, when the grease injection pressure is too low, the injected grease mostly flows into the bottom of the valve cavity, which usually occurs in small gate valves. The pressure of the grease injection flow control valve is too high. On the one hand, check the insulation gate valve and the grease injection nozzle. If it means that the hole of the remote control float valve is blocked, judge the situation and replace it under the full open condition of the spring closed band wrench; On the other hand, the plunger stop valve is lipid hardening. It is necessary to use cleaning fluid to repeatedly soften the failed sealing grease and inject new grease for replacement. In addition, the sealing model and sealing material also affect the grease injection pressure. Different sealing forms have different grease injection pressure. Generally, the grease injection pressure of hard seal gate valve is higher than that of soft seal gate valve.