Patent GB-627864-A (GB)
Title: Improvements relating to liquid depth or ship's draught or displacement indicators
IPC: B63B39/12
Filed: 1946-10-03
Abstract: 627,864. Indicating liquid levels. DOBBIE McINNES, Ltd., and MORE, J. Oct. 3, 1946, No. 29472. [Class 123(i)] [Also in Groups XIX and XXIX] In a pressure gauge of the manometer type which indicates through the intermediary of a gas, such as air, the depth of liquid in a tank, or of water above a datum level on a ship's hull, a diaphragm-type control cock is used comprising first and second branch passages connected, respectively, to the manometer reservoir and the liquid to be gauged, a common passage interconnecting the passages, third and fourth passages adapted to be connected, respectively, to the sight tube of the manometer and a source of air pressure, the third and fourth passages opening in the cock at a common surface, and a flexible diaphragm disposed adjacent this common surface and adapted to be moved manually towards and away from the surface to isolate the third and fourth passages from each other or to interconnect them. In the diagram shown in Fig. 1, the manometer comprises a sight limb 38, a reservoir limb 16, an extension 17, 18 for filling and draining the manometer, a vent 19, used during filling, and an overflow cup 20. The control cock 34 comprises, as a single unit, passages and associated pipe lines leading to the overflow 20, the reservoir 16, an air pump, and to the liquid tanks 36 or other liquid source to be measured. There is a spring-controlled pinoperated release valve 14, and a non-return valve 15 in the air pump line. All these valves are embodied in a single control cock having a lower body A, Fig. 2, and an upper body B between which is clamped a flexible diaphragm C of fabric and rubber. Branches 10 and 13 from the tanks 36 and reservoir 16 lead to a common annular groove in the part A, and branches 11 and 12 lead separately to the top of a flat seat 21 spaced slightly below the top face of part A. A one-way release valve 14 of the inflator type leads from the branch 11 just outside the part A, and a similar valve is pivoted in the branch 12 to allow air from a pump to be introduced therein. The upper part B has a screw therein carrying a swivelpad 24 and a handle 25 which when turned lowers the pad to depress the diaphragm C into contact with the seat 21 to isolate the branches 11, 12 from each other and from the branches 10, 13. A spring 27 and plunger 28 in the axial passage of branch 11 restores the diaphragm. A cover plate D fitted on top of the body part B has a window 26. The handle 25, on moving to closed position to isolate branches 11, 12, engages a lug 27 on a resilient split collar 30 to depress part of the latter which has a projection 29 thereon adapted to engage the pin 14a of valve 14 to open the latter and branch 11 to atmosphere. With the branches 11, 12 open and valve 14 closed, air from the pump will clear the line to the bell &c. used in the tanks 36 and balance the mercury in the limbs of the manometer. Reading is effected by closing branches 11, 12 and opening valve 14, by turning the handle 25, whereby the pressure in the bell necessary to balance the head of liquid in the tank is communicated to the manometer. When there are several tanks 36, each tank may have a cock similar to the lower body part A but with only two branches such as 11 and 13 leading thereto, controlled by raising and lowering a diaphragm as above described. A practical form of manometer is described wherein a glass or plastic sight tube 38 is supported between two rubber sleeve end supports clamped by screw-contractable annular clips to rigid supports in a plastic housing having a transparent front. The filling tube for the reservoir has a screwthreaded end closed by a cap, air being allowed to escape from the tube, during tightening of the cap, through a flat formed at the side of the pipe end. A shield is provided in the overflow-chamber so to prevent squirting of the mercury or other liquid. Two liquids such as oil and mercury may be used in the manometer. When the tank 36 has an internal pressure different from atmospheric, a balance line connects the valve 14 to the upper part of the tank, and a similar valve is incorporated in the balance line to enable the latter to be cleared of obstructions by the pump.