Patent GB-681083-A (GB)
Title: Liquid sampling apparatus
Inventor: LAMB JOHN
IPC: G01N1/10
Filed: 1951-07-18
Abstract: 681,083. Sampling liquid. SHELL REFINING & MARKETING CO., Ltd. July 18, 1951. No. 17031/51. Classes 106 (v) and 123 (i). Apparatus for sampling a liquid at a number of levels in a tank, such as oil in a tank ship, and for measuring its level, comprises means for winding and unwinding one or more suspending cables or tapes 19 and an operating cable or tape 23, means 34 for indicating the length of cable unwound, a sampling container 18 having a number of compartments, and a valve 39 operated by impulses from the operating cable so that it first opens and then closes each compartment in turn. The winding gear is enclosed in a gas-tight housing 16 pivoted at 80 on a tubular member 81 which can be attached to a gate valve on a stand pipe 'provided on the tank and comprises a hand-, wheel 28 for rotating a pair of pulleys 21 for two .tapes 19 attached to the sampling container and another pulley 24 for the operating tape 23. Perforations in the tapes engage pins 26 on pulleys 22 and 25 so that a shaft 29 is rotated and by means of a chain drive 32, the length of tape unwound is indicated on the counter 34. The annular sampling container 18 is divided into three closed compartments 18b and an open compartment 18a by walls 40, 41 and an open tube 39 forming a sleeve valve is fitted inside the bore 38 of the container. A pair of ports 42, 43 at different levels register with ports 44, 45 for each closed compartment 18b and for a gauge glass 46 fitted in the open compartment 18a. A spiral spring 47, wound up by a key placed in the slot 48, rotates the sleeve under the control of an escapement comprising upwards and downward-facing ratchet teeth formed on a flange 52 (see Fig. 3) at the top of the sleeve and a spring-loaded double-lobed pawl 53 connected to the operating tape 23; alternatively an electromagnetic device may operate the valve, in which case the tape 23 would be electrically conducting. For tensioning and de-tensioning the tape 23, it is engaged by a pulley 60 on a lever 61 pivoted on the shaft 29 and operated by a pin-andslot connection 62, spring-loaded lever 63, shaft 64 and handle 65. The handwheel 28 can be .located in two positions by a detent 67 and, in the outer position, a gear 68 on the hub of the wheel meshes with a gear 69 on a rotatable casing 70 containing a spiral spring. A thermometer 74 is fitted in a stopper 73 for each compartment. In use, with the gears 68, 69 disengaged, the container is lowered until it floats at a draught depending on the specific gravity of the liquid and this draught is registered by lifting the handle 65 so that the sleeve 39 is rotated to. bring the ports 42, 43 opposite the ports for the gauge glass 46, thus,admitting liquid to the glass and expelling air at the upper end. The ullage of the liquid is equal to the reading of the counter 34 plus the distance from the ends of the tapes to the surface of the liquid in the gauge glass. The handle 65 is then released and lifted again to bring the ports 42, 43 in register with the ports of the first closed compartment and the container is so designed that its buoyancy is destroyed when the first compartment has been filled to the level at which the container floats after the gauge glass has been 'filled. The first compartment may, if desired, be completely filled by allowing the container to sink a little and the container is then allowed to sink to the required levels, at each of which the handle 65 is lifted for a time sufficient to allow the compartment to fill, and is then released. Finally the container is allowed to sink to the bottom of the tank in order that the depth of water may be recorded on a strip of litmus paper attached to the side of the container. For continuously indicating the level in the tank as it is being filled, the empty container is lowered to the bottom while the gears 68, 69 are engaged so that the spring in the casing 70 is wound up and, as the container rises with the liquid, the spring takes up the slack in the tapes.