Patent GB-117081-A (GB)
IPC: G01N1/00
Filed: 1918-06-17
Abstract: 117,081. Aktiebolaget Ingeniorsfirma F. Egnell. June 16, 1917, [Convention date]. Hydraulic pumps.-In a gas-pumping apparatus especially for use in connexion with gas analysis and of the kind comprising a number of liquidpiston pumps each having two receptacles directly or indirectly connected and an overflow pipe from one of the receptacles as described in Specification 16561/08, the pumps and the connected pipes are so arranged that, at each stroke, a quantity of the pump liquid is discharged from an operative to an inoperative pump to render the first pump inoperative and the second operative, the measuring-receptacles of the gas analysis apparatus being filled and discharged in succession. As shown, two pumps P<1>, P<2> comprise pairs of receptacles b<1>, d<1> and b<2>, d<2> partly filled with mercury, the receptacles of the pairs communicating through holes in the side walls of the receptacles d<1>, d<2>. To the receptacles b<1>, b<2> are connected pipes c<1>, c<2> leading to the gas-measuring receptacles M<1>, M<2>, and to the receptacles d<1>, d<2> are connected pipes a<1>, a<2> loading through pressure-reducing valves D<1>, D<2> to the supply pipe a for the pressure agent, such as water or air under pressure. The receptacles d<1>, d<2> are connected by vertical pipes c<1>, c<2> to receptacles f<1>, f<2> from which overflow pipes g<1>, g<2> lead to the pipes c<2>, c<1> respectively. If the pump P<1> is operative and the pump P<2> inoperative, with the lower end of the pipe c<2> above the mercury level, when pressure is applied mercury is forced in the known manner from the receptacle b<1> to the measuring-receptacle M<1> and from the receptacle d<1> up the pipe c<1> until the preasure agent escapes to atmosphere through the pipe c<1>, the pressure agent communicating throughout with atmosphere through the pipe c<2> in the inoperative pump. The overflow of mercury from the pipe e<1> passes from the receptacle f<1> through the pipes g<1>, c<2> to the receptacle b<2>, which at the end of the first stroke contains enough mercury to render the pump P<2> operative, the loss of mercury from the pump P<1> rendering it inoperative for the next stroke. Gas samples for analysis are thus forced alternately from the receptacles M<1>, M<2>. To equalize differences in the quantity of mercury transmitted between the pumps, the pipes c<1>, c<2> are provided with ascending pipes h<1>, h<2> connected by a pipe i of V-shape, the apex of which is at such a height that normally no mercury passes it; but if one pump delivers more mercury than it receives, a quantity of mercury flows through the pipe i and produces equalization. In a modification, the receptacles b<1>, d<1> and b<2>, d<2> are not directly connected with each other, independent branches from the pipes a<1>, a<2> are connected to the various receptacles, and the pipes g<1>, g<2> are connected directly to the receptacles d<2>, d<1> respectively, and are of U-form to provide liquid seals. In another modification, the pipes g<1>, g<2> are connected to the pipes c<1>, c<2> respectively, and mercury is transmitted between the pumps through the pipes h<1>, i, h<2>, the pipe i being placed at a lower level to ensure its being operative at each stroke.