| 摘要 |
<p>A flow control device typically for protecting a seal (20) in a valve, wherein a body portion (5) has an orifice (8) allowing fluid flow, and the valve has a control portion (10) to allow and restrict fluid flow through the orifice. The flow control device has a fluid flow controller (30) between the body portion and the control portion in the form of at least one annular ring (35), disposed in a recess in one of the body portion and the control portion (10). The fluid flow controller (30) defines a leak path through the device that is opened and closed by a pressure differential acting across the annular member. Typically the application of a pressure differential across the fluid flow controller moves the ring(s) to one end of the recess and reduces the cross sectional area of the leak path available to the fluid, thereby diffusing the fluid flow through the orifice (8).</p> |
