| 摘要 |
For maintaining a predetermined pressure at a controlled pneumatic device, a unit of this invention has a body with an inlet port connectable with a pressure gas source, an outlet port connectable with said device, a pressure chamber at all times communicated with the outlet port, and an annular valve seat through which gas can flow from the inlet port to the pressure chamber. The position of a valve element that throttles gas flow through the valve seat is controlled by a diaphragm having one surface exposed in the pressure chamber and a helical compression spring having an inner end bearing against the opposite diaphragm surface. A cam rotatably supported on the body controls the position of the other end of the spring, for quick stepless adjustment of spring preload and thus of outlet port pressure. An eccentric bushing enables calibrating adjustment of the position of the cam axis for either a maximum or a minimum outlet port pressure. A tubular stem connecting the diaphragm with the valve element bleeds off pressure gas from the pressure chamber when pressure in that chamber exceeds the value for which the cam is adjusted.
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