GB627056A - Improvements in and relating to gages - Google Patents

Abstract

627,056. Fluid-pressure gauging-apparatus. RUPLEY, F. L. Oct. 3, 1946, No. 29532. [Class 106 (ii)] In fluid-pressure gauging-apparatus a stabilizing chamber communicates with the source of fluid and also with the gauge head which has an orifice with a variable effective outlet area, this chamber having associated therewith a discharge valve adapted in response to a predetermined pressure in the chamber to discharge fluid therefrom into a damping chamber, the latter communicating with a fluid flow responsive instrument. As shown, a housing 47 forming a fluid-tight reservoir has an inner structure in which two restricting devices 49 are arranged. The first device is supplied with fluid, such as air, under controlled pressure through a conduit 48, and communicates by a passage 53 with the second device which is connected by passages 57, 58, 59, 62 with a feeler gauge head 66. Also communicating with the passage 57 is one end of a Bourdon tube 78 acting as a stabilizing chamber, the free end of which has an exhaust aperture controlled by a valve 83 pivotally carried by a block 85. The block 85 is urged by a spring into engagement with an adjusting- screw 88 by which the exhaust of fluid from the tube 78 is regulated. The fluid is exhausted into a damping chamber formed by the housing 47 and passes through a pipe 95 to the bore 96 in a fluid-flow pressure gauge 93 of the type comprising a tapered tube 101 in which is a light bobbin 104, the fluid passing to atmosphere through the upper open end of the tube. The restricting-devices 49 each include thimbleshaped members 50, each with an orifice 51. The fluid on passing through these devices is alternately throttled and expanded, resulting in the elimination of moisture and dirt ; the fluid temperature is also to some extent controlled. The gauge head 66 is secured to the housing 47 by a screw connection, and comprises a discharge port 68 in a member 69, Fig. 6, disposed radially of the head, and a feeler button 70 disposed opposite the port 68 and carried by a spring 71 secured to the head 66. For internal gauging, the head 66 may be cut away at 109 to provide a three-point contact. In a modification a single restricting orifice may be incorporated at the junction of the passages 58, 59. In operation, the discharge of fluid through the port 68 in the head 66 is controlled by a work-piece and this variation affects the pressure in the passage 57. The pressure in the latter controls the bending of the Bourdon tube 78 and the rate of exhaust therefrom to the pressure gauge 93. To avoid the constant use of master gauges for checking purposes, the port 68 is closed and the fluid pressure adjusted so that the bobbin 104 registers at a set point in the tube 101 corresponding to a predetermined work-piece dimension. In a further modification, the stabilizing chamber communicates separately with a discharge chamber having a discharge opening which communicates with a damping chamber, and with a cylinder in which is a piston secured to a valve controlling the discharge in the discharge chamber.