| 摘要 |
<p>The three-way pressure unloading valve is of welded construction and has three inlets (2,3,4). A central wall (7) is provided with a screwed-in seat cage (10) with ports (11) spaced around its circumference. A piston (13) is guided by a rod (32) which slides in a tube (20) connected to the base (12) of the seat cage (10). The tube (20) is secured by a nut (24) which is sealed with an O-ring and which houses a gland (25). The piston (13) can either seal the outlet (4) or when it is raised the piston skirt covers the ports (11) and shuts off the outlet (3). The hole (15) in the piston balances the pressure across the piston and so reduces the force required to operate the valve.</p> |
