Patent GB-351003-A (GB)
Title: Improvements in devices for measuring and indicating fluid pressures
IPC: G01L7/16
Filed: 1930-03-15
Abstract: 351,003. Piston-and-spring pressure gauges. OKILL, J., 14, Foxcovers Road, Lower Bebington, Cheshire, and TATE, J. R., 434, Chorley Old Road, Bolton. March 15, 1930, No. 8363. [Class 106 (ii).] Relates to apparatus specially applicable for measuring the maximum pressure obtained in a cycle of pressure variation and comprises a construction adapted for high pressures and provided with a differential piston or the equivalent so that the effective pressure is that on an annular area thus enabling the employment of sufficiently strong pistons while at the same time obviating the use of a heavy balancing spring. In the form shown in Figs. 4 and 5, the cylinder block B is provided with a screwed boss for engaging a screwed hole in the cylinder of an internal-combustion engine through a base b<3> in which the pressure fluid is conducted to a space b<5> between two plungers A3, A<4> the other ends of which abut against cross-bars c<2>, c<3> connected together by rods c<4> passing through lugs c<6> on the cylinder block. The cylinder block B is secured in a U-shaped frame H having an opening h<1> through which a pin c<1> protrudes to engage the short arm E of a spring-pulled bell-crank lever fulcrummed on the part H the long arm e<2> forming a pointer moving over a scale h<2>. The spring S is located in a casing K screwed into the frame H and screw-threaded to take the screw-threaded portion of a compression sleeve P having a hand-wheel p<1> and graduated indicating thimble p<2>. A pressure transmission rod R has fixed to it a ring r<1> and a ring s<1> fixed to the spring has a pin engaging a hole in the ring r<1>. A pin s<3> on a ring s<2> attached to the other end of the spring engages a hole in the wheel. The spring S and rod R both rotate with the hand-wheel p<1>. The pressure in the engine cylinder acting on the pistons A3, A<4> is effective on an area equal to the difference between the areas of the pistons, and the connected crosspieces are moved against the influence of the spring S which is tensioned by moving the hand-wheel until balance is effected against the maximum pressure, the pointer e<2> then giving a slight fluttering movement. The pressure may be read off on the scales k<1>, p<3>. A wheel t<3> on the rod R may gear with a wheel t<2> on the shaft of a counter T registering the pressure. In a modification the pistons A<3>, A<4> may engage the legs of a bow-shaped frame which engages a washer acted upon by the spring. In another form, a piston is formed with two different diameters engaging corresponding bores, the pressure fluid being admitted to act on the annulus between the diameters. In a third form, the piston is tubular and the pressure acts on the annular end. The Provisional Specification also states that the device may be combined with the apparatus described in Specification 319,253, [Class 106 (ii), Dynamometers &c.], for measuring pressures below as well as above atmospheric pressure and with the apparatus therein described for indicating, and for cooling and lubricating the pistons.