| 摘要 |
<p>A device (30) for controlling or metering fluid flow in either direction through a conduit. The device (30) comprises an elongated body (31) having two end walls (32,33) forming an internal chamber (34) therebetween. Disposed within the chamber (34) is a free piston (51) having an axial passageway (52) extending therethrough. One end wall (32) of the device (30) has a metering orifice (41) and one or more bypass openings (43). The other end wall (33) also has a metering orifice (42) and one or more bypass openings (44). Fluid flow through the device (30) urges piston (51) against the end wall (33) in the direction of fluid flow. In this position, the piston (51) blocks the bypass opening(s) (44) in the end wall (33) in the direction of fluid flow. Fluid flowing into the device (30) can pass through the bypassing opening(s) (43) of the opposite end wall (32). Fluid flowing out of the device (30) must pass through the metering orifice (42) in the end wall (33) in the direction of the fluid flow. Upon a flow reversal, the piston (51) is urged against the opposite end wall (32). In this position, fluid will flow through the metering orifice (41) in the end wall (32) of the fluid direction and through the bypass opening(s)(44) in the opposite end wall (33). The device (30) is adapted for use in a reversible vapor compression air conditioning system. In this application, the sizes of the two orifices (41,42) are different so that one can provide proper metering for cooling mode operation and the other can provide proper metering for heating mode operation.</p> |
