GB353994A - Improvements in and relating to apparatus for indicating the speed and/or distance travelled by a ship through water or aircraft through the air - Google Patents

Abstract

353,994. Pitot-tube apparatus. DRYSDALE, C. V., Admiralty, Whitehall, London. June 4, 1930, No. 17271. [Class 69 (i).] In Pitot-tube apparatus of the kind wherein the difference of pressure between the orifices is utilized to operate a member which generates a balancing pressure centrifugally, a diaphragm actuates a member which operates a relay controlling a variable speed device which regulates the centrifugal device. In one form, opposite sides of a diaphragm 2, Fig. 1, are in communication, through pipes 16, 17, with the static and pressure orifices ; movement of the diaphragm actuates the piston valve 5 of a liquid pressure system to displace a piston 53, Fig. 8. A rocker 52 carrying two additional brushes 50 of a constantly running dynamoelectric machine 49 which are connected to pairs of diametrically arranged brushes 56, 57 of a motor 58, is thus rotated, to produce rotation of the fan 12, the speed and number of revolutions of the motor 58 each being recorded on one or a number of devices. A centrifugal governor may be arranged to take the place of the fan 12. In another form, the centrifugal device comprises three rotatable concentric cups 25, 26, 27, Fig. 3, the edge of the cup 26 serving as a diaphragm while the space 35 between the cups 25, 26 is filled with mercury. A float 34 controls the position of the piston valve 5. The device shown in Fig. 6 is disposed between the Pitot-head and the diaphragm chamber ; the level of the line of separation between the water and oil being observed and regulated in the concentric reservoirs 39, 40, two-way cocks 45, 46 being provided together with oil containers 41, 42. Air traps 37, 38, and a double two-way cock 47, which may be operated to allow water at high pressure to be discharged through the Pitot-head, are also furnished. Specification 349,930, [Group XXXVII], is referred to.