ApplicationNo. 743559 filed on 08/12/1991
US Classes:417/53, PROCESSES417/63, WITH SIGNAL, INDICATOR, OR INSPECTION MEANS417/282, Plural separate sensing means for a single fluid controller417/474, Elongated flexible chamber wall progressively deformed604/153Deformable resilient chamber type
ExaminersPrimary: Hepperle, Stephen M.
Attorney, Agent or Firm
International ClassesF04B 043/12
AbstractA method and apparatus for detecting proximal and distal occlusions of flexible tubing in a positive displacement pump. A volumetric pump (30) includes a motor (146) that rotatably drives a cam assembly (142). The rotating cam assembly actuates a plunger (48), causing it to compress a pumping portion (34b) of a flexible tubing (34), compression of the tubing displaces fluid trapped within the pumping portion, causing it to flow past an outlet cracking valve (52). A proximal pressure sensor (44) and a distal pressure sensor (56) each produce signals indicative of the pressure within the proximal portion and distal portion of the flexible tubing, which are used to determine whether a proximal or distal occlusion of the flexible tubing has occurred. Both pressure sensors comprise strain gauges connected to flexures that apply a spring-biased force against the proximal and distal portions of the flexible tubing. These sensors thereby respond to the cross-sectional size (diameter) of the tubing, as affected by fluid pressure therein. Proximal and distal pressures are thus monitored without violating the integrity of the flexible tubing passing through the volumetric pump.
Field of SearchPROCESSES
WITH SIGNAL, INDICATOR, OR INSPECTION MEANS
Plural separate sensing means for a single fluid controller
Elongated flexible chamber wall progressively deformed
Distributor formed from integral portion of flexible wall pumping member
Having pumping chamber pressure responsive distributor
Mechanically actuated distributor
Deformable resilient chamber type