Pressure responsive fluid flow control valves

Abstract

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.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Application [0002] This invention relates to fluid-flow control valves, and more particularly to pressure responsive fluid-flow control valves particularly adapted for use with Intravenous (IV) infusion applications. [0003] 2. Background Of The Invention—Description Of Prior Art [0004] In the administration of blood, and other fluids, it is sometimes required to rapidly increase the flow rate through the IV set to administer a large or larger volume of IV fluid. This is usually done by applying pressure to the IV line. One very common means of doing this is by manually squeezing a bladder or bulb in the IV administration set. When that is done, especially if the needle or cannula, or the other venous access device, cannot accommodate the sudden increase in fluid-flow, the pressure in the line usually quickly rises to a large and often dangerous value. Such pressure can easily exceed 20 psi (greater than 1,000 mm Hg) for a brief peri...

AI Technical Summary

Benefits of technology

[0009] It is yet another object of this invention to provide new and novel fluid pressure responsive valves for incorporation into intravenous administration sets and systems with relative ease, within the fluid-flow path between the source of the fluid and the patient / recipient that is to receive the fluid, and permits normal fluid flow with little or no flow restriction.

[0012] It is yet still another object of this invention to provide new and novel pressure responsive valves, primarily for IV use, which work passively without operator adjustment and facilitate a normal fluid flow in safe fluid pressures independent of pressure applied to the fluid.

[0015] It is still another object of this invention to provide new and novel fluid pressure responsive valves, primarily for IV use, that are constructed of materials so that the fluid-flow path can be sterilized and made non-pyrogenic by conventional methods and so that single use thereof is economically feasible.

[0017] The instant pressure response valve (PRV) incorporates a deformable sensor chamber. The geometry of the sensor chamber allows normal fluid-flow to proceed with very low flow restriction when the applied pressure is well below a predetermined “critical value”. When the fluid pressure is at or exceeds the “critical value” the valve functions by change of the geometric configuration of the sensing chamber with sufficient force to either overcome the input pressure seen in the chamber or by action of a valve member to crimp fluid flow tubing to the sensing chamber; or by deforming so as to activate a feature in the valve to cut off fluid flow into the sensor chamber; all without interfering with outflow from the valve to the intended use or user. The pressure in the valve is automatically reduced below the “critical value” by the continued fluid flow from the sensing chamber, or part of the chamber, to once again permit fluid inflow. The pressure responsive valve (PRV) utilizes a small number of simple plastic components to accomplish the pressure limiting function, and to maintain very small size, and small priming volume. The components contacting the fluid are relatively easily formed by injection molding or by welding or sealing tubing components, and are presumably sterilizable by conventional means. Example embodiments of simplified valves employing these mechanisms are shown in the detailed description that follows:

Problems solved by technology

When that is done, especially if the needle or cannula, or the other venous access device, cannot accommodate the sudden increase in fluid-flow, the pressure in the line usually quickly rises to a large and often dangerous value.

The use of a syringe to rapidly infuse fluid in pediatric patients through a small needle can produce a similar unacceptable pressure.

If the venous access device is not seated properly, this high pressure can be applied to the patient's veins, and damage the vein and surrounding tissue.

In addition, some devices in the IV line are not made to withstand such a high pressure, and can leak when subjected to this pressure.

While a valve such as the one shown and described in U.S. Pat. No. 5,453,097 patented on Sep. 26, 1995 to J. R. Paradis for “Control of Fluid Flow” may very well permit fluid under unacceptable and dangerous pressures to flow into and out from the valve and from there to a person receiving the fluid infusion.

As such the valve is obviously only suitable for gasses and not for IV uses.

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