American type flanged expansion butterfly valve are National Letters Patent products of our company. It gathers together the function of seal adjustable flanged butterfly valve and expansion joint. It reaches the effects of getting twice the result with half the effort in project installation and old pipeline maintenance & conversion, and the replacement of conveyance valve. It also can release from various stress besides the pipeline caused by difference in temperature and groundwork subside. The design of seal structure accords with American Water Supply Association standards & requirements, manufactured with GB Flanged Joint Standard. It is applicable for various; liquid and gas pipes & power lines. It is widely used to cut-off and throttles the function in the municipal works, power station, waterworks, city plumbing and water disposal system etc.