How is the bellows stop valve processed? What are the processing steps of the bellows stop valve? The bellow stop valve manufacturer will introduce it to you.

Up to now, the valve industry has been able to produce 12 categories, more than 3000 models, more than 4000 specifications, such as gate valves, globe valves, throttle valves, plug valves, electric valves, diaphragm valves, check valves, safety valves, pressure reducing valves, steam traps and emergency cut-off valves.

The high working pressure is 600MPa, the large nominal diameter is 5350mm, the high working temperature is 1200 ℃, and the low working temperature is - 196 ℃. The applicable medium is water, steam, oil, natural gas, highly corrosive medium (such as the concentration of concentrated nitric acid, etc.), flammable medium (such as styrene, etc.), toxic medium (such as hydrogen sulfide), explosive medium and radioactive medium (metal circuit pure water, etc.)

The valve pressure parts are made of cast copper, cast iron, ductile iron, high silicon iron, cast steel, forged steel, high and low alloy steel, stainless acid resistant steel, Hastelloy alloy, Inconel alloy, duplex stainless steel, titanium alloy, etc. It can also produce various electric, pneumatic and hydraulic valve actuators In the face of such a large number of valve varieties and such complex working conditions, to select the valve products suitable for installation in the pipeline system, I think that the characteristics of the valve should be understood first; Secondly, master the steps and basis of valve selection; Furthermore, the principle of valve selection shall be followed

There are generally two types of valve characteristics, service characteristics and structural characteristics

Service characteristics: it determines the main service performance and scope of use of the valve. The service characteristics of the valve include: valve category (closed valve regulating valve safety valve, etc.); Product type (gate valve, globe valve, butterfly valve, ball valve, etc.); Material of main parts of the valve (sealing surface of valve body, bonnet, stem and disc)

Valve transmission mode, etc Structural characteristics: it determines some structural characteristics of the installation, maintenance and other methods of the valve. The structural characteristics include: the structural length and overall height of the valve and the connection form of the pipeline (flange connection, threaded connection, clamp connection, external thread connection, welding end connection, etc.); Form of sealing surface (bead welding and spray welding of valve body with inserted ring thread ring); Valve rod structure (rotary rod lifting rod), etc

The steps and basis for valve selection are as follows:

Select Steps

Specify the purpose of the valve in the equipment or device, and determine the working conditions of the valve: applicable medium working pressure, working temperature, etc

Determine the nominal diameter and connection method of the pipe connecting the valve: flange thread welding, etc

Determine the way to operate the valve: manual, electric, electromagnetic, pneumatic, hydraulic, electrical, or electro-hydraulic linkage. Therefore, the pressure drop generated by the valve is small, so the flow is good

The materials of the shell and internals of the selected valve shall be determined according to the working pressure and temperature of the medium conveyed by the pipeline: gray cast iron, malleable cast iron, nodular cast iron, carbon steel, alloy steel, stainless acid resistant steel, copper alloy, etc

Determine the type of valve: gate valve, globe valve, butterfly valve, throttle valve, safety valve, pressure reducing valve, steam trap, etc

Determine valve parameters: for automatic valves, determine the allowable flow resistance discharge capacity, back pressure, etc. according to different needs, and then determine the nominal diameter of the pipe and the diameter of the valve seat hole

Determine the geometric parameters of the selected valve: structural length, flange connection form and size, size in the height direction of the valve after opening and closing, size and number of bolt holes, overall dimensions of the valve, etc

Use existing data: valve product catalog, valve product sample, etc. to select appropriate valve products

Basis for valve selection While knowing and mastering the steps of valve selection, the basis for valve selection should also be further understood

Purpose, operating conditions and control mode of the selected valve

There are many materials for diaphragm valve parts, including ferrous metals, nonferrous metals and their alloys of different brands. Materials for diaphragm valve parts shall be selected according to the following factors:

Nature of working medium: working pressure, working temperature, corrosion performance, whether solid particles are contained in the medium, whether the medium is toxic, whether it is flammable and explosive, medium viscosity, etc. Compressor failure, gas source header leakage 2, gas source, no information

Requirements for valve fluid characteristics: flow resistance, discharge capacity, flow characteristics, sealing class, etc The main action element of the bellows trap is that the metal bellows is filled with a liquid whose gasification temperature is lower than the saturation temperature of water. There are two options: the opening temperature is lower than the saturation temperature 15 and 30. The bellows trap is sensitive, not afraid of freezing, small in volume, and resistant to overheating. It can be installed at any location with a back pressure ratio greater than 80. It can discharge non condensable gas. The bellows is solid, long in service life, easy to maintain, and wide in use

The following principles shall be followed when selecting valves:

The flow passage of the valve used for cut-off and opening medium is a straight through valve with small flow resistance, so the valve used for cut-off and opening medium is usually selected The downward closed valve (stop valve plunger valve) is less selected because of its tortuous flow path and higher flow resistance than other valves. In the occasion where higher flow resistance is allowed, the closed valve can be selected 5. The valve stem seal is reliable. Because the valve stem only rotates without lifting, the packing seal of the valve stem is not easy to be damaged, and the sealing capacity increases with the increase of the medium pressure

The valve used for flow control usually selects the valve easy to adjust the flow as the flow control valve A downward closing valve (such as a globe valve) is suitable for this purpose because its seat size is proportional to the stroke of the closing element Rotary valves (plug valves, butterfly valves, ball valves) and flexure body valves (clamp valve diaphragm valves) can also be used for throttling control, but they are usually only applicable to a limited range of valve diameters The gate valve uses a disc shaped gate to make a cross cutting movement to the round valve seat opening. It can better control the flow only when it is close to the closed position, so it is usually not used for flow control. Oil and gas with high temperature and low concentration organic salt with low corrosivity

The valve for reversing and shunting can have three or more channels according to the requirements of reversing and shunting Plug valves and ball valves are more suitable for this purpose. Therefore, most of the valves used for reversing and diverting flow are selected as one of these valves However, in some cases, other types of valves can also be used for reversing and shunting as long as two or more valves are properly connected with each other. The sealing ring is alloy steel surfacing, so the hard seal ball valve is not

Valve for medium with suspended particles When there are suspended particles in the medium, it is suitable to use the valve with wiping function whose closing element slides along the sealing surface If the back and forth movement of the closing element to the valve seat is vertical, particles may be clamped. Therefore, this valve is only applicable to basically clean media unless the sealing surface material can allow particles to be embedded. 1 The structural design of the valve sealing pair is unreasonable or the manufacturing and equipment accuracy cannot meet the requirements

Ball valve and plug valve can wipe the sealing surface during opening and closing, so they are suitable for medium with suspended particles At present, no matter in the petrochemical industry or in the pipeline system of other industries, the operating frequency and service of valve applications are ever-changing. To control or even slight leakage, there are also several important and key equipment valves. The final control of pipelines is valves, and the service and performance of valves in various fields are correct

We should know the processing steps through the above introduction of the bellows stop valve manufacturer!