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put the valves back ng from China at good prices

Offer type: salePublished: 20.11.2014
The check valve is a device designed for unimpeded passage of liquid, gaseous or mixed working environment through the pipeline in one direction and providing automatic overlapping flow in the event of a change in direction. Since the reverse flow of the working fluid, usually occurs when the malfunction of the compressor or emergency on the pipeline, the valve is referred to the category of protective pipe fittings. However, there are some types of valves, which, depending on design in its action to a greater extent related to pressure relief type valve.
By design check valves are of several types: lifting, swinging, ball, plunger, and others. However, among all these valves in a special way distinguish only two types - this is a swing check valves and non-return valve lifting, which is most prevalent in the nuclear, oil, gas, chemical industry and many other industries. The popularity of check valves due to their simple design, reliable sealing, reliable and effective in operation, and excellent maintainability and low cost products.
Lifting the check valve consists of a housing similar to the housing of the shutoff valve, and gate which performs a reciprocating motion perpendicular to the direction of movement of the working environment, thereby opening and closing the stream. Because the boarding gate on the saddle is under its own weight, the valve mostly installed in horizontal pipelines. However, there are different types of check valves for inclined and vertical sections of the pipelines, the construction of which the spring is used, performs the functions of the additional clamping element. In other words, lifting the check valves are divided into spring and springless.
The rotary valve has a shutter, which under the action of the fluid flow rotates around a horizontal axis at a certain angle, thereby providing unimpeded passage. At the moment when the flow stops or starts moving in the wrong direction, the bolt slams under their own weight. As previously pipelines of large diameters was used check valves of suitable size, sometimes it has happened that when the collapse of heavy shutter device goes down. In addition, when the valve increased the likelihood of water hammer in the piping system.
Today, all these disadvantages are completely absent due to the fact that, given past experience, manufacturers began to produce swing check valves of two types - simple and unstressed. To the category of simple valves are devices, the diameter of which does not exceed 400 mm. As in such a case the diameter of the locking element does not have a large weight, it beats not have a serious vozdeistviyami neither pipeline system, either on the device itself. In turn, swing check valves large diameter, used for main gas and oil pipelines, equipped with special devices, which makes it fit the locking element on the seat is smooth and soft.
It should be noted that the design of the lifting of the valves allows to achieve high integrity in comparison with other types of valves. Therefore, the lifting valve is most often used on pipelines with clean liquid or gaseous environment, where its potential can be realized at 100%. As for the rotary valve, then it is essential for pipelines transporting crude oil and petroleum products, synthetic oils, explosive, toxic, liquid, and mixed environments. The reliability of these types of valves is amazing - their average life can reach several thousand cycles of opening and closing.
Elements of check valves made from austenitic stainless steel, stainless steel or high-temperature ferritic steel, various types of cast iron, corrosion-resistant, heat-resistant alloys, etc. to ensure the device the necessary degree of tightness, at the saddle valve is applied sealants, which depending on the parameters of the working environment are made of special plastics, rubber, metal alloys or corrosion-resistant steel. Just like any other valves, check valves are manufactured with different installation positions, ways of joining the pipeline and in various climatic design.
Materials of main parts:
Body material: carbon steel, alloy steel, stainless steel;
Disc: carbon steel, alloy steel, stainless steel;
Axle: stainless steel;
Saddle: welding stainless steel