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put SN DN50-300 from China at very good prices

Offer type: salePublished: 20.11.2014
Seller:Guo Lucy
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SN PN 1.6 MPa
Valve steel wedge ng with sliding spindle flange is designed for installation in pipelines with diameters DN- 50, 65, 80, 100, 125, 150, 200, 250, 300, 350, 400, 450, 500, 600, 700, 800, 900, 1000 as shut-off devices at pressure up to 1.6 MPa and temperatures up to +425C. Valve si is installed in a horizontal pipeline with the flywheel up. In a vertical line at position (flat) with horizontal spindle.
The working environment is non-aggressive liquid and gaseous petroleum products, water, steam at temperatures up to +S
A tight seal class "A" according to GOST 9544-93
The conventional pressure PN, MPa (kgf/cm²) - 1,6 (16)
The connection to the pipe - flanged with connecting dimensions according GOST 12815-80
Housing material - steel 25L
Material of seal - steel NZ
Drive - manual (handwheel)
The device and principle of operation
In General, the design of the valve consists of a body and cover forming a cavity in which the working medium under pressure and within which is placed the shutter. The housing has two ends for attaching the valve to the pipeline are connecting the ends of the flange, coupling and welded). Inside the case are usually two seat, parallel or at an angle to each other, to their sealing surfaces in the closed position pressed to the sealing surface of the shutter. The shutter is moved in the plane perpendicular to the axis of passage of the medium through the housing, by means of a spindle or rod. The spindle running nut forms a threaded pair that rotation of one of these elements provides the movement of the shutter in the right direction. Such a solution is most common and is used when running manually or electrically. When using hydro or pneumatic actuator rod makes with the shutter only translational motion. The spindle with one end inside the housing connected to the shutter, and the other passes through the cover and gasket (which is mainly used as a sealing device (valves) for connection with the control valve.
The design of the locking bodies wedge gate valves
In gate valves seat in the housing located at a slight angle to each other, and the shutter is a device in the form of a wedge - rigid, elastic or disc, which in the closed position fits tightly into the space between the saddles. Depending on the operating conditions chosen a particular type of wedge.
Hard wedge
Hard wedge provides reliable sealing of the locking body, but this requires high precision machining to match the angle of the wedge with the angle between the seat body. The lack of rigid wedge - risk of jamming of the shutter and the inability or difficulty opening the valve as a result of fluctuations in the working environment temperature, wear or corrosion of the sealing surfaces.
Dual wedge
A wedge formed by two discs arranged at an angle to each other and rigidly connected to each other. It drives have the capability of self relative to the seat body, so some errors made in the manufacture of saddles housing, do not affect the tightness in the closed position. Dual wedge gate reduces the possibility of jamming, which is characteristic of a hard wedge, and, despite the complexity of the design, has a number of other advantages - low wear of the sealing surfaces, high integrity shut-off body, the lesser the force required for closing.
Wedge disc gate valves included in ship fittings also called clinker.
Elastic wedge
This modification of the dual wedge, disks which are connected by the elastic element, able to Flex, providing intimate contact between the sealing surfaces in the closed position. In this shutter reduced the possibilities for self drive compared to the dual, while still the ability to compensate for some deformation of the body from the pipeline loads and temperature fluctuations. The advantages of the elastic wedge - does not require laborious fit shutter body (as for the hard wedge) and the design is more simple than the dual. Thus, the elastic wedge to a certain extent, smooths imperfections and combines the advantages of two other types of gate valves.
Valve with retractable spindle
In this construction, the threaded spindle and the driving nut located on the outside of the valve body. The spindle lower end connected to the shutter and when the rotation of the drive nut to open the valve does with shutter only translational movement, the upper end of the spindle extends to the stroke of the shutter. To move the spindle running nut is raised above the upper part of the cover (i.e. above the seal about the stroke of the shutter in the design, which is called the tow site.
Advantages of this design are no harmful effects of the working environment for running the site and easy access for maintenance, and therefore less wear on seals and higher reliability pair of threaded and seal.
The disadvantage of such valves is the increase in building height and mass due to the output spindle of the cover is not less than the diameter of the passage and the need for this reason, when mounting to leave space for the output spindle.
Materials and methods of manufacture
The sealing surfaces of the valves are made without rings, with brass rings, PTFE, with the surfacing of stainless steel, of rubber (gate valves can be covered wedge, and a hose from it is made pinch the hose).
Valves with cast iron bodies and aluminum alloy are performed by means of casting. The same way it is manufactured and steel valves, but some of them, and valves made of titanium alloys produced by the method of welding the billets produced by stamping from sheet metal. Such valves is called welding. By their characteristics, performance and durability, they are not inferior to cast valves, and Vice versa, parts of bodies and covers such valves are made of a material more durable and carefully controlled, the quality of which is higher than the casting. When this welding technology and methods of control of welded joints provide high quality body parts, permitting use of such valves in important facilities, including nuclear power.