Pumping arrangement for intravenous supply of fluids
First Claim
1. A pumping arrangement comprising:
- means for subjecting fluid to pressure;
input and output controllable valve means for restricting fluid flow provided on a respective input and output side of said subjecting means;
means responsive to fluid pressure in delivery tubing connected in operation between the output controllable valve means and the point of application of the required fluid for detecting an increase in fluid pressure; and
means responsive to increases in pressure detected by said fluid pressure responsive means for controlling both said input and output controllable valve means to open,whereby fluid under excess pressure in said delivery tubing is released back towards a source of fluid connected in operation to said input controllable valve means.
1 Assignment
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Accused Products
Abstract
A pumping arrangement including a squeezing device for deforming a length of pliant p.v.c. tubing first in one direction locally to reduce its volume and in another tending to restore its original cross-section and, on either side of squeezing device, inlet and outlet valves which operate by occluding the tubing. The squeezing device and the valves are controlled by a microprocessor control unit such that inlet valve is open and outlet valve shut while the squeezing device is relaxed and thereafter outlet valve is open and inlet valve shut while the squeezing device is operated to deform the tubing, this sequence repeating. Downstream of the output valve is a pressure responsive device providing input to the control unit whereby upon a rise in pressure in the delivery portion of tubing due to a restriction, the squeezing device is disabled and valves are open together to allow excess fluid to pass back towards the fluid source.
52 Citations
20 Claims
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1. A pumping arrangement comprising:
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means for subjecting fluid to pressure; input and output controllable valve means for restricting fluid flow provided on a respective input and output side of said subjecting means; means responsive to fluid pressure in delivery tubing connected in operation between the output controllable valve means and the point of application of the required fluid for detecting an increase in fluid pressure; and means responsive to increases in pressure detected by said fluid pressure responsive means for controlling both said input and output controllable valve means to open, whereby fluid under excess pressure in said delivery tubing is released back towards a source of fluid connected in operation to said input controllable valve means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification