GB945835A - Improvements in and relating to pressure indicating apparatus - Google Patents

Abstract

945,835. Pressure gauges. D.W.E.KYLE. March 9, 1960 [March 9, 1959], No. 8112/59. Heading G1L. A maximum pressure indicator for measuring fluctuating fluid pressures comprises a chamber to which a pressure gauge can be connected, means for maintaining an adjustable fluid pressure in the chamber and means for applying a pressure derived from the pressure to be measured to the fluid in the chamber. As shown, Fig. 1, an instrument for measuring the maximum pressure in a cylinder of a diesel engine has a chamber 18 with sides formed by a piston 22, moveable by means of a screw 23, and by a piston 19 on which pressure from the cylinder acts through a piston 17. Movement of piston 19 is restricted by a head 24 abutting a striker plate 15. The chamber 18 and a pipe 26 connecting it to a pressure gauge 27 are filled with a liquid, e.g. lubricating oil, The valve 31 is closed and the pressure is increased to one greater than that expected in the cylinder by depressing piston 22. The lower end of a body 11 is attached to the indicator cock of an engine cylinder so that the pressure in the cylinder acts on piston 17 and the pressure in chamber 18 is gradually reduced by retracting piston 22. When the pressure in chamber 18 is just below the maximum pressure in the cylinder each occurrence of maximum pressure in the cylinder acting on piston 19 moves the needle of the gauge 27, Thus the needle of the gauge 27 flickers to indicate the required reading. A relief valve 33 is provided to protect the gauge and a reservoir 28 with a plunger 29 is provided. Bodies 11,16, are finned and have air spaces 35 to dissipate heat from the engine. In an alternative form, Fig. 2, a piston 19 forming a side of the chamber has a larger area than piston 17 on which the pressure to be measured acts so that this pressure is reduced by a known ratio.