Patent GB-624715-A (GB)
Title: Improvements in and relating to fluid operable gauges
IPC: G01B13/00
Filed: 1946-10-03
Abstract: 624,715. Fluid-pressure gauging-apparatus. RUPLEY, F. L. Oct. 3, 1946, No. 29531. [Class 106 (ii)] [Also in Group XXIX] A fluid-pressure gauging-apparatus is provided with a fixed orifice one side of which communicates through passage means with a pressure gauge and also with an orifice in a gauge head adapted to be varied by engagement with a workpiece, while the other side of the fixed orifice communicates with conduit means arranged for admission of the fluid, the conduit means also communicating with a valve the opening of which is controlled by the pressure communicated thereto. The feeler unit can be constructed for internal, external, and height gauging, and the indicating unit comprises any type of pressure gauge. As shown, in Fig. 3, the apparatus comprises a housing 48, constituting a reservoir 49, closed by a removable hood 53, a flexible diaphragm 50 separating them and having mounted in a central aperture therein a valve body 57 having axial and transverse passages 60, 59, to allow the fluid to be byepassed to atmosphere from the housing 48. Within the body 57 is a spring-urged valve 66a controlled by an adjusting-screw 70. A guide rod 73 for a weight 74 is screwed into the valve body 57 and is guided at its lower end in a recessed boss 77 in the base of the housing. A measuring unit 80, communicating with the interior of the housing 48, has an exchangeable thimble 82 therein having a fixed orifice 83 to allow fluid to pass to a passage 84. Ports 85, 87 in the unit 80 communicate respectively with a pressure gauge 86 and flexible tubing 88 which is connected with a feeler unit 89. The housing 48 has a fluid inlet port 103 connected by a conduit to a restricting device 105 to which fluid is supplied by a conduit 106. The device 105 comprises a sleeve 107 having arranged therein cup-like members 108, each with an orifice 109 to form a series of expansion chambers, whereby moisture and dirt particles in the fluid are precipitated and the pressure and temperature rendered substantially constant. The feeler unit 89 comprises a gauge head 90, Fig. 4, with an end discharge port 92. A button 95 disposed opposite the port 92 is grooved peripherally for engagement by the prongs of a leaf-spring 100 secured by screws 102 to the head 90, the spring being arched at 101 to facilitate movement of the button towards the port 92 along a line coincident with the axis of the port. Projections 94 are arranged at the end of the head 90. A handle or stand 112 for the feeler unit 89 may be provided. In operation, the button 95 engages a work-piece and controls the discharge of fluid through the port 92, and the pressure gauge 86, which shows the variation in pressure between the ports 83, 92, is calibrated to show the size of the work-piece. Pressure variations within the reservoir 49 due to pressure variations in the passage 84 in the unit 100 will be compensated by movement of the diaphragm 50 which will increase the fluid flow through the valve body 57 to atmosphere. In a modification shown in Fig. 8, a housing body 117, closed by a side plate 118, has mounted therein two restricting devices 119, 123 in series joined by a passage 122. The device 123 communicates with a passage 126 wherein one end of a Bourdon tube 127 is secured. The free end 129 of the tube 127 has a discharge port therein controlled by a valve head 137 formed on a stem 135 pivoted on a block 132 which can be adjusted towards the tube end, against the action of a spring 142, by a screw 140. An increase in pressure in the passage 126 will tend to straighten the Bourdon tube and increase the flow of fluid therethrough. Fluid passes from the passage 126 through a port 147 in a removable plug 146, into a passage 148 with which communicate a pressure gauge 149 and a feeler unit 150. In this case the feeler unit is arranged for internal gauging and the port discharges fluid radially through a removable plug opposite which a button feeler 154 on a spring arm is disposed. In a further modification the body part and feeler unit are rigidly connected and can be readily mounted in a stand for height or internal gauging. The casing is cylindrical, with the indicating dial arranged at one end, and a single restricting unit at the opposite end formed as a handle or to fit in a stand clamping arrangement. The fluid enters the casing from the restricting unit, and a Bourdon tube constituting a byepass port substantially as shown in Fig. 8, is incorporated. The pressure gauge is also a Bourdon tube the free end of which moves a pointer through a lever and sector and pinion gearing. The passage to the feeler unit extends radially of the casing and is screw-threaded to receive the unit. Auxiliary standard gauges for checking purposes are eliminated since the pressure gauge may be marked with a "set point" equal to the stabilized pressure when the button completely closes the discharge port ; this can be equivalent to a particular dimension to be gauged, and the scale correspondingly graduated.