截止阀和逆止阀(截止止回阀)
GLOBE AND NON-RETURN (STOP-CHECK) VALVES
- 通常安装截止阀时，都是使得流进的流体和压力位于阀瓣的下方。如果流体流向与常规不同，在安装阀门之前请咨询厂家。在某种应用条件下，或者当阀门配置气动执行机构或电动执行机构时，在安装阀门时使得流进的流体位于阀瓣上方可能具有成本较低的优点。如果根据这些条件进行执行机构选型时，必须小心谨慎，以确保阀门安装正确。
Globe valves are normally installed with flow
and pressure under the disc. Always consult with the factory before
installing valves with flow in the other direction. Under certain service
conditions or when valves are equipped with cylinders or electric motor
actuators, there may be a cost advantage in designing and installing
the valves with flow over the disc. If actuators are sized for these
conditions, care must be taken to assure valves are installed correctly.
- 截止阀适用于大多数的节流应用。但是，截止阀不能用在开启度小于10~20%的节流应用。这样做可能导致剧烈的振动、噪音以及阀瓣和阀座的损坏。可以采用流量较小的较小通径的截止阀，这将使得截止阀能够具有更大的开启度，从而避免受到损坏。如果需要持续性的节流应用，则可能需要配置控制阀。
Globe valves are suitable for most throttling
applications; however, they should not be used for throttling at less
than 10-20% open. This can cause excessive vibration, noise and damage
to disc and seats. Use of smaller valves with lower flow capacity may
permit the valve to be open a greater percentage, thus avoiding damage.
Continuous severe throttling applications may require a control valve.
- 逆止阀(截止止回阀)具有与截止阀相同的功能，还有活塞提升式止回阀的功能，防止出现意外的回流。这种阀的阀杆并不连接到阀瓣上，当阀杆处于开启位置时，阀瓣可以根据流体流向自动进行调节。
Non-return (Stop-Check) valves provide the same
function as a globe valve with the addition of providing piston-lift-check
valve protection in the event of backflow. The valve stem is not connected
to the disc, and when the stem is in the open position then the disc
is free to respond to the flow.
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