| 摘要 |
1,214,490. Fluid-pressure servomotor systems. ROBERTSHAW CONTROLS CO. Dec.19, 1967 [Dec.19, 1966], No.57681/67. Heading G3P. [Also in Division F2] A pressure regulating valve to control flow from a gas source through an inlet 28, to a burner through an outlet 30 comprises a diaphragm valve 34, see Division F2, closing one side of a chamber 36 which is connected via a passageway 48 with a chamber 26 connected via and on/off valve 20 and bleed pressure regulator 18 to the outlet 30. A bleed passage 44, with a restrictor 46 connects the inlet 28 with the chamber 26. Valve 20 is controlled by a thermal bulb 22. When the space in which the bulb 22 is located has no heat requirement, valve 20 shuts a passage to the regulator and chamber 36 is connected with inlet 28 via passage 44, and the valve 34 is closed by a spring 42. When there is a demand for heat, valve 20 is opened, and chamber 36 is connected with the outlet connection 30, via the regulator 18. The valve is then opened by inlet pressure at 28 until the pressure in the outlet reaches the set point of the regulator 18 whereupon it closes and pressure builds up in chambers 26 and 36 to close the valve 34. To prevent hunting the diaphragm valve 34 is either formed with a diametral rib, Figs.2 to 9, (not shown) or a cavity connecting with the space within its seat, Figs.10, 11, (not shown) which can have diametrally extending hubs, Figs.13, 14, (not shown). |
