1, when the media required flow direction, the role of the valve under medium power, is open; when the upstream medium, because the weight of the valve and the valve by the media backward force, the valve and valve seat sealing surface density closed together, to prevent the media countercurrent purposes. 2, the sealing surface of the valve body and stainless steel welding. 3. The length of the structure of the valve according to [1] provides that the provisions of flange dimensions according to ANSI B16.5 for. [Check] ANSI flange structure and installation instructions 1, American Standard check the valve disc-shaped, around the shaft for rotational movement of the valve channel, due to internal valve passage into streamlined, flow resistance ratio l butterfly valve, suitable for low flow rates and flow changes in large-caliber seldom occasions, but not for pulsatile flow, the sealing performance is less than lift. Ill with butterfly valve points, double valve type and most type three, according to the three main forms of valve diameter points, the purpose is to prevent the media back in time to stop the flow or weakened hydraulic shock. 2, American standard check valve along the vertical centerline of the body slide valve, check valve internal thread can only be installed on a horizontal pipe, small diameter high pressure valve in the ball valve can be used. The butterfly valve as the valve body shape of the shut-off valve (shut-off valve can be common with), so it is fluid drag coefficient. Its structure is similar to the cut-off valve, and the valve body with the same cut-off valve. Valve and valve cover the lower part of the upper guide sleeve is formed with Jane, Jane valve guide freely in the valve lift light guide, Jane, when the medium downstream, thrust open the valve by the media, when the media stops the flow, the valve by self vertical landing on the seat, to prevent the media from the backflow effect. Butterfly valve straight-through media channels and export channel direction perpendicular to the direction of the seat; the same vertical lift check valve, the direction of media and export channel seat-channel direction, the flow resistance is smaller than the straight-through. 3, American Standard valve: valve rotation about the pins inside the valve seat. Simple disc check valve structure, can only be installed on a horizontal pipe, sealing well. 4, the US standard valve: valve slide along the centerline of the valve body. Pipeline valve is a valve emerging, its small size, light weight, good processing is one of the check valve development. But the fluid drag coefficient is slightly larger than the swing check valve. 5, compression-type check valve: This valve is used as boiler feed water and steam off valve, which has lift check valve and globe valve or angle valve integrated function. In addition, there are - some do not apply to the pump outlet check valve installation, such as a foot valve, spring-type, Y-type and other valve. [Check] ANSI flange detail the role of this type of valve is only allowed media to flow in one direction, and stop the flow direction. Usually the valve is automatically work in a direction of flow of the fluid pressure effect, the valve opens; opposite direction of fluid flow from the fluid pressure and the valve from the coincidence of acting on the valve seat, thereby cutting off the flow. American Standard valve which threaded check valve, butterfly valve belongs to this type of valve, which includes swing check valves and lift check valves. Swing Check Valve with ordinary hinge, there is a door on the same disc freely leaning tilt seat surface. To ensure that every time the valve seat surface reach the appropriate position, the valve flap design in the hinge mechanism, so that the valve has enough space to swing and make a real flap valve, comprehensive engagement with the valve seat. Valve can all be made of metal can also be embedded in the leather, rubber on metal, or synthetic coverage, depending on performance requirements. Swing check valve in the fully open position, the fluid pressure virtually unimpeded, so by the pressure drop across the valve is relatively small. Lift check valve located on the valve body sealing surface located seat. Addition to this valve disc is free to lift, the other part as the cut-off valves, fluid pressure from the valve seat sealing surface of valve lift, medium return valve flap led to a seat, and cut off the flow. Depending on conditions, the valve flap can be all metal construction, can also be embedded in the form of rubber or rubber ring in the valve holder. Like off valves, fluid channels through the lift valve is narrow, so through the lift valve pressure drop than the swing check valve a little bigger, and swing check valves for flow restrictions 150LB American standard 10-inch carbon steel flange check other explanation swing check valve flanged Uses for nominal pressure PN1.6 ~ 16.0Mpa, operating temperature -29 ~ 550 ℃ in the petroleum, chemical, pipeline variety of conditions, such as fire stations, cut off or connected media. Suitable medium: water, oil, steam, acid media. Product Features 1. Product design and manufacturing structure according to GB12236 design, reasonable structure, reliable sealing, beautiful appearance. 2. The valve seat sealing surface using Stellite (stellite) cobalt-based alloy cladding made of wear-resistant, high temperature resistant, anti-abrasion performance, long service life. 3. can be a variety of standard pipe flanges and flange sealing surface types to meet various project needs and user requirements. The full range of body materials, packing, gaskets according to actual working conditions or user requirements reasonable matching can be applied to all kinds of pressure, temperature and medium conditions. 5. The valve pin rotation around the outside of the seat, reducing violent shock occurs when closed. 6. The valve pin and the pin is connected using a built-in structure, reduce leakage and the use of more reliable. The main parts of the material described Body WCB ZGCr5Mo ZG1Cr18Ni9Ti ZG1Cr18Ni12Mo2Ti bonnet WCB ZGCr5Mo ZG1Cr18Ni9Ti ZG1Cr18Ni12Mo2Ti valve WCB ZGCr5Mo ZG1Cr18Ni9Ti ZG1Cr18Ni12Mo2Ti WCB ZGCr5Mo ZG1Cr18Ni9Ti ZG1Cr18Ni12Mo2Ti rocker seat 25 1Cr18Ni9Ti 1Cr18Ni9Ti 1Cr18Ni12Mo2Ti pin 1Cr17Ni2 1Cr18Ni9Ti 1Cr18Ni12Mo2Ti sealing ring coated pad 1Cr18Ni9Ti 1Cr18Ni12Mo2Ti