Pressure responsive fluid flow control valves
In one set of embodiments a selected section of tubular stock has its ends welded together to form a pillow-like pressure sensing device with an entry tube and an exit tube each configured to facilitate insertion of the pressure sensing device into the flow path of IV infusate in an IV administration set or system. Fluid pressure in excess of a predetermined amount reconfigures the pressure sensing device from a generally oval configuration to a generally circular configuration to restrict and/or cut off fluid flow into the device while permitting fluid flow from the device to reduce the fluid pressure again reconfiguring the device back to its generally oval configuration and permitting fluid flow into and through the device. In other embodiments a fluid pressure sensing device is formed with a fluid entry chamber and a fluid exit chamber interconnected by a passageway and provided with a piston that reacts to an increase in fluid pressure above a predetermined amount to close off the interconnection between the chambers and fluid flow into the exit chamber. Continued fluid flow from the eit chamber results in a reduction of fluid therein and reopening of the fluid passageway between the chambers.
1. A fluid pressure responsive valve for use in delivery of an IV infusate to a patient, the valve comprising:
an input port;
an inflow chamber;
a pressure sensor;
an outflow chamber; and
an output port,
wherein the input port receives the IV infusate and directs the IV infusate to the inflow chamber,
wherein a wall of the inflow chamber comprises a valve seat,
wherein the pressure sensor reacts to changes of fluid pressure in the outflow chamber, and comprises a valve operator and a valve cap,
wherein the valve operator comprises a concave wall from the perspective of the outflow chamber,
wherein the fluid pressure responsive valve does not comprise a spring, and wherein the valve operator is connected to the valve cap such that when fluid pressure in the outflow chamber is in excess of a critical limit, the concave wall stretches, thereby displacing the valve cap to seat against the valve seat so that fluid from the inflow chamber to the outflow chamber is restricted and/or closed-off without a spring, whereby flow of the IV infusate from the inflow chamber to the outflow chamber is only permitted when the fluid pressure in the outflow chamber is less than the critical limit,
wherein the valve seat is tapered,
wherein a side of the valve cap is tapered,
wherein the output port directs the IV infusate from the outflow chamber to the patient,
wherein the input port and the output port are parallel,
wherein the fluid pressure responsive valve is sterilizable, and non-pyrogenic, and
wherein the critical limit is in a range from 250 to 350 mm Hg.
2. The fluid pressure responsive valve of claim 1 , wherein the fluid pressure responsive valve is biocompatible.
3. The fluid pressure responsive valve of claim 2 , wherein the fluid pressure responsive valve is compatible with blood products.
4. The fluid pressure responsive valve of claim 2 , wherein the fluid pressure responsive valve does not leach out any substance which is harmful to tissue.
5. The fluid pressure responsive valve of claim 1 , wherein the concave wall comprising an elastic flexible diaphragm.
6. The fluid pressure responsive valve of claim 5 , wherein the elastic flexible diaphragm comprises silicone.