Physiological draining system with differential pressure and compensating valves

Claim 1

A compensating valve for inclusion into a system having a tube for the transport of cerebrospinal fluid from a first region in the body to a second region in the body, wherein the relative elevation of the two regions can change when the patient changes position, thereby creating the risk of possible overdrainage from the said first region, said compensating valve comprising: a body having an internal cavity, and including a base, a peripheral sidewall, and force means for exerting a mechanical force, said base and sidewall partially defining said cavity; a valve seat extending in said cavity having a circular seat facing away from said base, there being an outlet passage opening axially into said cavity inside said valve seat; a flexible diaphragm extending across said cavity making a fluid sealing fit with said peripheral wall, overlaying said valve seat, having a central seal so disposed and arranged in one axial position as to seal on said valve seat and having a central aperture within said seal, the body having an inlet port to said cavity on the same side of said diaphragm as said valve seat and said diaphragm facing said force means on the other side from the inlet passage, said seal being normally seated on said valve seat and being displaceable therefrom by a distance which is a function of inlet pressure, outlet pressure, and force applied to said diaphragm by said force means; a fluid-sealing barrier sealing the end of the body opposing the base to close the cavity at the side of the diaphragm away from the base; whereby when said inlet pressure sufficiently exceeds outlet pressure, the diaphragm tends to move said seal axially away from said valve seat in opposition to the tendency of the force means to move the seal toward the seat.