Patent GB-850184-A (GB)
Title: Fluid sampler and metering device
Inventor: BROWN STEPHEN SLADE
IPC: G01F3/38
Filed: 1957-09-18
Abstract: 850,184. Sampling liquids. ESSO RESEARCH & ENGINEERING CO. Sept. 18, 1957, No. 29394/57. Class 106(5) A device for sampling liquids in a receptacle or flowing in a pipe comprises a piston 23 which has a hollow rod 17 traversible across the receptacle or pipe between two oppositely disposed openings 12, 13 one of which contains a valve 33 opened by the rod in its extended position in order to discharge the representative sample isolated within the hollow rod. The device may be fitted in a metering tank similar to that described in Specification 850,183 and be cyclically operated to take a sample at each operation of the metering tank. The piston 23, Fig. 2, slides within a cylinder 11 having pipes 27, 28 connected to a fluid pressure source and when pressure is supplied above the piston the rod 17 moves across the receptacle and presses down the valve 33 until passages 35, 31 are aligned so that the trapped sample can be discharged. A plug 21 on a rod 18 extends within the hollow rod 17 and seals off the lower interior of the latter until, at the end of the stroke, a taper 26 at the top of the piston clears the plug and allows the pressure above the piston to assist the discharge of the sample. In a modification, the hollow piston rod slides on the outside of a shaft extending from the top of the cylinder 11 and ending in a perforated pipe extending across the receptacle to the valve 33. The piston rod, in descending, traps the liquid within the perforated pipe and, as the rod depresses the valve 33, the piston 23 moves below the opening of a passageway in the shaft and the pressure above the piston lifts a non-return valve to allow this pressure to pass into the perforated pipe and assist discharge of the sample. As shown in Fig. 7, the sampling device is combined with a measuring system comprising a measuring tank 50 fitted with an inlet and discharge valve 55 and an upper float chamber 51. In the discharged condition of the tank, a float 76 in a chamber 59 is in the lowered position and it opens a valve 75 to transmit pneumatic pressure from a source 80 to the diaphragm 89 of a valve 90 through a valve 84. Valve 90 is thus caused to connect a conduit 97 to an exhaust conduit 110 and pressure is released from the diaphragm 105 of a valve 53 fitted between the chamber 51 and the tank 50, from the diaphragm 102 of a valve 103 connected to the cylinder 11 of the sampling device and from the diaphragm 100 of the inlet and discharge valve 55. Simultaneously, but with a delay action, pressure passes through an orifice 86 and chamber 87 to the diaphragm 88 of valve 84 and stops the pressure flow to diaphragm 89. Valve 53 is thus opened to discharge the contents of chamber 51 into the tank 50, valve 55 connects an inlet pipe 56 to the tank 50 so that the latter starts to fill and the valve 103 connects pressure to the cylinder 11 so that the sampler rod is withdrawn from the receptacle. The fall of float 70 in the chamber 71 actuates valve 72 to supply pressure to diaphragm 89 through delay valve 92 and thereby maintain pressure on diaphragm 89 of valve 90. When the tank 50 has completely filled, liquid enters chamber 51 and raises the float 70 so that valve 72 bleeds conduit 91 to exhaust conduit 911 and allows valve 92 to close with delay action and, prior to closing of valve 92, releases pressure from diaphragm 89 of valve 90 so that valve 90 supplies pressure to diaphragm 105 and closes valve 53. Simultaneously, valve 103 is actuated to supply pressure to move the sampler rod downwardly through the tank. Diaphragm 100 is also actuated to change over valve 55 to connect the tank 50 to a discharge chamber 58 and conduit 62. As float 76 in chamber 59 rises, valve 75 is actuated to bleed conduit 82 to exhaust conduit 83 and pressure on diaphragm 89 is released through delay action valve 84. It is important that valve 53 closes before valve 55 moves to discharge position and that valve 55 moves away from discharge position before valve 53 opens and to ensure this speed control valves 111 and 112 may be placed adjacent the diaphragm 105 and 100. A counter 115 may be operated by the valve 90 to register each filling and discharging cycle. Temperature compensating control mechanism may be incorporated.