ZFV provide triple offset type bi-directional butterfly valve. Bi-directional butterfly vlave can seal well to pipeline flow in both directions ( flow from left to right , or from right to left; from upward to downward, or from downward to upward). and normal uni-directional butterfly valve can only seal to flow in one direction.
General bi-directional butterfly valve seat design is diifferent from uni-directional valve, it has a removable seat ring in body seat position.
Uni-directional valve do not have this removable seat ring, it only makes seat by weld overlay to body seat position.
Because the design difference of two type valves, the installation of valves are also different.
There is a arrow marking on uni-directional valve, the arrow direction should be comply to flow direction when the valve be installed to pipeline.
And the bi-directional valve can be installed in any direction on pipeline.
But some customer request a arrow on bi-directional valve, too. when they install the valve, they process like install uni-directional valve, for the purpose of longer using life. We think this is a good idea and recommond to other customer this design for their choosing.
Zhejiang Zhengfeng Valve