GB593493A - Density responsive device - Google Patents

Abstract

593,493. Fluid- and pressure-actuated valves. BENDIX AVIATION CORPORATION. Feb. 26, 1945, No. 4802. Convention date, March 1, 1944. [Class 135] [Also in Groups XX and XXVII] In apparatus utilizing a pressure-responsive element and a temperature-responsive element co-ordinated to obtain a response to changes in density, one of the elements has a non- resilient pivotal connection with a lever through which it operates the member to be controlled, and a part moved by the other element has a pivotal connection with the lever providing a fulcrum about which the lever is turned by the first element, the pivotal connection being slidable along the lever by movement of the second element to alter the mechanical advantage of the lever. As shown in Fig. 1, the bellows 10, highly evacuated to render it responsive to pressure changes only, and spring-loaded tomaintain it distended at atmospheric pressure, moves the needle valve 20 in the airmetering passage of a carburetter 15 by rocking the lever 17 about the pivot-pin 34, caused to slide in the slot 35 by movement of the liquid- or liquid and gas-filled temperatureresponsive bellows 27 through the yoke 30 and the bell-crank lever 31. The initial angle between the lever 17 and the bell-crank lever 31, which determines the type of temperature correction, is set by the adjusting-mechanism 37. The response of the device may be proportional to the ratio of pressure to either absolute temperature or the square root of absolute temperature, or to intermediate functions. In a modification (not shown) the pressureresponsive bellows 10 is replaced by a bellows responsive to both temperature and pressure. In this case the lever 17 is initially set at an obtuse angle to the lever 31. In a further modification (not shown) the pivot-pin is moved directly by the free end of the temperature - responsive bellows. Specification 523,895, [Group XXVII], is referred to. The Specification as open to inspection under Sect. 91 comprises also the embodiment shown in Fig. 3 (Cancelled) and Fig. 4 (Cancelled). A bellows 40, responsive to pressure and temperature or to pressure only, is secured to a housing 42 and is surrounded by a bimetallic temperature-responsive element 52. The latter is connected at its upper end to the housing and at its lower end through the link 55 with the pivot-pin 56 sliding in a slot 57 in the arm 58 rigidly secured to the stem of the needle valve 47, which is mounted for axial and rotational movement in a cap 43 at the free end of the bellows. It is stated that movement of the spiral 52 will result in rotation of and consequent raising or lowering of the needle valve 47 as a result of the interaction of the cam surfaces 44 and 45, and that the amount of movement will be determined by the position of the cam member 59 attached to the lower end of the bellows and contacting the link 55 to vary its throw. This subject-matter does not appear in the Specification as accepted.