Three factors should be considered when sizing swing check valves ; the pressure drop across the valve , the flow velocity of the fluid through the valve , and the location of the valve in relation to other piping components 在选择旋启式止回阀的通径时应该考虑到三个因素；通过阀门的压降，流体通过阀门的流速，与阀门其它管道部件的相对位置。
Like closing valves , fluid movements of check valve through the channel is narrow and therefore the lifting of check valve through the pressure drop kai xuan than some big - check valve , and the rotary kai - flow check valves are very few restrictions 像截止阀一样，流体通过升降式止回阀的通道也是狭窄的，因此通过升降式止回阀的压力降比旋启式止回阀大些，而且旋启式止回阀的流量受到的限制很少。
