Pressure-compensated infusion regulator

Claim 1

A dual-diaphragm, adjustable-rate, pressure-compensated infusion regulator, comprising: an inverted-cup-shaped first housing part having substantially cylindrical walls and a downward-facing bottom surface with an inlet port, said first housing part being provided with an inlet connector connectable to a relatively high-pressure infusion-liquid source; a second housing part attachable to said first housing part and having an outlet port; an intermediate member comprised at least of an annular portion interposed between and rotatable relative to either of said first and said second housing parts, and having means rendering it stationary relative to the other one of said housing parts; a flexible main diaphragm retained along a peripheral portion thereof in said intermediate member and defining with its upper surface an inlet chamber and with its lower surface, an outlet chamber; a flow-regulating valve comprised of a valve head accessible to said high-pressure source and a valve stem one end of which is attached to said valve head; a flow-attenuating element of adjustable attenuating effect disposed in the path of said liquid from said inlet chamber into said outlet chamber; a flexible auxiliary diaphragm retained along a peripheral portion thereof in a high-pressure region upstream of said inlet chamber and incorporating a valve seat for said valve head, said valve seat and said valve head defining between them a gap through which the liquid passes on its way from said high-pressure source into said inlet chamber, said valve head being adapted to be acted upon by a first force tending to reduce said gap, and by a second force tending to increase said gap, a state of equilibrium between said forces defining the set point of said pressure-compensated infusion regulator; wherein said force, by acting upon said flexible auxiliary diaphragm and flexing same in a direction towards said main diaphragm, enhances the effect of said second force.