GB1123122A - Pumping apparatus of the flexible tube type and method of operation thereof - Google Patents

Abstract

1,123,122. Rotary pumps. TECHNICON INSTRUMENTS CORP. March 15, 1966 April 5, 1965], No. 11214/66. Heading F1F. [Also in Division B8] In a rotary pump for use in chemical analysis, a plurality of flexible tubes 64 are periodically and sequentially constricted by rollers 72 attached to a pair of driven endless chains 68 to effect a peristaltic pumping action, a portion of each of which tubes is supported beneath the rollers by a spring-loaded flat table or platen (54), Fig. 5 (not shown), one of the tubes 64A being filled with a relatively inert fluid, e.g. air, and connected at its outlet end to that of an adjacent tube 64B containing a reagent fluid, and the flow of inert fluid from the tube 64A being periodically interrupted by a pin 94 whereby the reagent fluid entering tube 106 is segmented. The pin 94 is carried by one end of an arm 92 pivotally supported by a bearing 93 and having a cam surface 100 at its end remote from the pin, said surface being periodically engaged by an extension 102 of a bearing pin for each roller. The end of the arm 92 carrying the pin is biased downwardly by a tension spring 98 so that a portion of the tube 64A lying on a block 86 is normally constricted by the pin. Thus, quantities of inert fluid enter the tube 106 in phase with the peristaltic pumping action and the consequent segmentation of the reagent fluid in the tube 106 effects proper proportioning of the reagent fluid relative to a sample fluid flowing in a tube 64C when these fluids are mixed in an outlet tube 110. This arrangement provides compensation for the fluctuations in the rates of flow of fluids in the tubes 64B, 64C and allows these tubes to have different diameters. Segmentation of the sample fluid may be effected in the upstream portion of a flexible tube (152B), Fig. 10 (not shown), by periodically injecting an inert fluid e.g. air, into the inlet end (160) of said tube within a container (162) for said fluid, the inert fluid being supplied through a flexible tube (152A) controlled by a pin (94') in a manner similar to that shown. The pins 94, (94') and the parts associated therewith may be replaced by a solenoid operated valve (not shown in the drawings), which is actuated by the rollers. Alternatively, a sample fluid and a reagent fluid flowing in flexible tubes (204A, 204B), Fig. 9 (not shown), due to the action of rollers (202), are mixed when they enter a tube (208) whose outlet end lies in a tube (212) connected to a mixing coil (214), segmentation of the mixture of fluids being effected by an inert fluid e.g. air, entering the tube (212) adjacent the outlet end of the tube (208) from a flexible tube (204C), through a tube (210) made of a material, e.g. P.T.F.E., having a relatively low surface-tension. The tube (212) is made of a material, e.g. glass, having a relatively high surface-tension whereby a quantity of the inert fluid is held in the tube (210) until the pressure developed in the tube (204C) by the rollers is sufficient to drive it into the tube (212).