Flow Metering And Shut-off Valve

Abstract

A combined flow metering and shut-off valve having inner and outer valve parts which are axially movable relative to one another to effect relative axial movement of a metering valve plug on one part into and from a metering bore in the other part for regulating and blocking flow through the valve flow passage. The describing valve is an intravenous flow control valve in which the outer valve part is a plastic barrel containing the metering bore and the inner valve part is a plastic sleeve which carries the valve plug and is threaded to the barrel for relative axial movement of the barrel and sleeve by relative rotation of the same.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to flow control valves and more particularly to a combined flow metering and shut-off valve.

2. Prior Art

As will appear from the later description, the flow control valve of the invention may be used for a variety of flow controlling purposes. However, the valve is intended primarily for use as an intravenous flow control valve and will be described in this connection.

Medical treatment of a patient often involves intravenous injection or feeding of various solutions into the patient's body, a typical intravenous feeding system comprises a stand for supporting a container filled with an intravenous solution, a tube extending from the container and fitted at its end with a needle for insertion into the patient's body, and a valve in the tube for regulating the rate of flow of the solution to the patient. Valves for this purpose must regulate the solution flow with great precision, must be capable of effective sterilization, and must be sealed against the entrance of foreign matter into the solution.

SUMMARY OF THE INVENTION

This invention provides a combined flow metering and shut-off valve which satisfies the above and other requirements of an intravenous flow control valve and hence is ideally suited to this purpose. As noted earlier, however, the valve may be used for other purposes.

The valve has inner and outer valve parts which are movable axially relative to one another and provide a flow passage including an axial flow metering bore in one part. The other valve part includes a flow metering valve plug which is movable into and from the metering bore by relative axial movement of the valve parts to regulate or meter and to totally block flow through the passage. To this end, the valve plug has a tapered portion providing a flow space between the plug and the wall of the metering bore. The taper of this portion is such that the effective cross-sectional flow area of the flow space increases as the plug retracts from the bore and decreases as the plug enters the bore. When fully inserted into the bore, the valve plug completely closes the bore to block flow through the valve flow passage.

The particular valve described is an intravenous flow control valve whose outer part is a tubular barrel containing the metering bore between the barrel ends and whose inner part is a sleeve closed at one end by a wall from which the valve plug projects. Entering one end of the barrel is an axial opening which opens to one end of the metering bore and receives the closed or walled end of the valve sleeve. The opposite or outer ends of the barrel and sleeve provide coupling ends through which the valve passage extends. The barrel and sleeve have mating threads, such that relative rotation of the barrel and sleeve causes their relative axial movement to effect movement of the valve plug into and from the metering bore.

The valve plug is cylindrical and sized to fit closely in the metering bore. Entering the circumference of the plug is at least one tapered longitudinal groove or flow slot which opens through the tip of the plug. This flow slot provides a flow passage between the plug and the wall of the metering bore whose effective cross-sectional area progressively increases as the plug retracts from the bore to increase flow through the valve and progressively decreases to reduce flow as the plug enters the bore. The hose of the plug is sized to fit snugly in the metering bore to close the latter completely when the plug is fully seated in the bore. The valve plug and the valve barrel may also have confronting valve seating faces which abut to block flow when the valve is closed by full insertion of the valve plug into the metering bore.

Preferably, the intravenous valve barrel and sleeve are constructed of plastic and the valve is designed to be disposable. The valve barrel and sleeve are sealed to another, preferably by a sealing bead about the sleeve, to prevent leakage and entrance of foreign matter into the valve passage.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an intravenous feeding system embodying the present valve;

FIG. 2 is an enlarged axial section through the valve when closed;

FIG. 3 is a section taken on line 3--3 in FIG. 2;

FIG. 4 is a section similar to FIG. 2 with the valve open;

FIG. 5 is a section taken on line 5--5 in FIG. 4; and

FIG. 6 is a fragmentary exploded perspective of the valve.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 illustrates a typical intravenous feeding system for feeding a solution, such as a saline solution, to a patient. The system includes a stand 10 from which hangs a container 12 filled with an intravenous solution. The container hangs upside down with its mouth lowermost. Secured to the lower mouth of the container is a cap 14 with a depending coupling nipple 16. The present flow metering and shut-off valve 18 is secured to the nipple. Extending from the lower end of the valve is a tube 20 whose lower end is secured to an intravenous needle (not shown) for feeding the intravenous solution to the patient. Valve 18 is adjustable to regulate and cut off the solution flow.

Turning to FIGS. 2-6, valve 18 has inner and outer valve parts 22, 24 which are axially adjustable relative to one another and provide a flow passage 26 through the valve. One valve part, in this instance, the outer part 24 has an axial flow metering bore 28 which forms a portion of the valve passage 26. The other or inner valve part 22 has a flow metering valve plug 30 which enters the bore 28 and is movable into and from the bore by relative axial movement of the valve parts to regulate and block flow through the valve passage. To this end, the valve plug has a tapered portion 32 which forms with the wall of the metering bore 28 a flow passage 34 whose effective cross-sectional flow area increases as the plug retracts from the bore and decreases as the plug enters the bore. The plug, when fully inserted into the bore, completely closes the bore.

Describing the valve 18 in greater detail, the outer valve part 24 comprises a tubular valve barrel which contains the metering bore 28 between the barrel ends. Entering the normally upper end of the barrel is an axial opening 36 whose lower end opens to the upper end of the metering bore 28. The lower end of the barrel is reduced to form a coupling nipple 38 containing a passage 40 which opens to the lower end of the metering bore 28. About the upper end of the bore is an internal annular wall surface 42 of the barrel.

The inner valve part 22 comprises a sleeve having a normally lower end 44 which enters the upper barrel opening 36 and a normally upper coupling end 46 which is enlarged to approximately the same outside diameter as the upper end of the valve barrel 24. Extending axially through the sleeve is a passage 48, the upper end of which is slightly enlarged to receive with a friction fit the container cap nipple 16. Extending across the lower inner end of the valve sleeve 22 is an end wall 50 with ports 52 which communicate the sleeve passage 48 with the space 54 between the wall and the inner barrel surface 42.

The flow metering valve plug 30 is formed integrally with and projects axially from the under side of the sleeve wall 50. This plug has a lower cylindrical end 56 which fits closely but slidably within the metering bore 28 and an enlarged annular shoulder 58 at the base of the plug facing the inner barrel surface 42. The tapered portion 32 of the plug comprises a tapered longitudinal groove or flow slot which enters the circumference and opens through the lower tip end of the plug. This slot is tapered to increase in depth toward the tip of the plug. The upper end of the slot 32 terminates a distance from the valve plug shoulder 58 to provide between the slot and shoulder a smooth cylindrical portion 60 of the plug which is sized to fit snugly in and seal the metering bore 28. The particular valve shown has two diametrically opposed tapered flow slots 32 in the valve plug 30.

The valve sleeve 22 and barrel 24 have mating threads 62 for imparting relative axial movement to the sleeve and barrel when they are rotated relative to one another. A seal 64 is provided between the sleeve and barrel to prevent fluid leakage from the valve passage 26 and entrance of foreign matter into the passage. In the particular valve shown, the valve sleeve and barrel are constructed of a relatively rigid though yieldable plastic material and the seal 64 comprises an integral sealing bead about the lower end of the valve sleeve 22.

Valve 18 is closed by rotating the valve sleeve 22 and barrel 24 relative to one another to fully insert the valve plug end 56 into the metering bore 28, as shown in FIG. 2. In this closed position, the base portion 60 of the plug is located within and seals the bore, and the confronting barrel and plug surfaces 42, 58, which provide confronting valve seating surfaces, abut to form an additional flow blocking seal closing the valve passage 26. The valve is opened by rotating the sleeve and barrel in the opposite direction relative to one another to retract the valve plug end 56 from the metering bore 28. This action elevates the upper ends of the plug flow slots 33 above the barrel seating surface 42 to permit flow through the slots. It is evident that the effective cross-sectional flow area of the slots, and hence flow through the slots, increases as the valve plug is retracted from the metering bore and decreases as the plug enters the bore.

Preferably, the valve sleeve 22 and barrel 24 are externally knurled at 66 to facilitate relative rotation of these parts. Also, the valve may be provided with a scale 68 on one valve part and an index or reference 70 on the other part for indicating flow rate through the valve.

The valve 18 is installed in the intravenous feeding system of FIG. 1 by inserting the container cap nipple 16 into the upper end of the valve sleeve passage 48 and fitting the upper end of the tube 20 over the lower coupling end 38 of the valve barrel 24. The valve may then be adjusted by rotation of the barrel to open and close the valve as well as to regulate flow of solution by gravity from the container 12, through the valve, to the base 20.

While the valve has been described in connection with its use in an intravenous feeding system, it obviously may be used for other purposes.

Claims

The inventor claims:

1. A valve comprising outer and inner valve parts each comprising a one piece molded plastic part,

said outer part comprising a tubular barrel having a relatively large diameter cylindrical portion at one end, a relatively small diameter nipple at the other end, and an axial flow metering bore between said ends opening at one end to the interior of said cylindrical portion and at the other end to an axial passage through said nipple,

said inner part comprising a sleeve having an axial flow metering plug at one end slidably fitting in said metering bore, a cylindrical coupling portion at the other end, and an intermediate portion between said sleeve ends having an axially presented transverse wall about said plug, said cylindrical sleeve portion being threaded in said cylindrical barrel portion, whereby said metering plug is adjustable axially in said metering bore by relative rotation of said parts,

said sleeve having a central passage opening at one end through said opposite sleeve end and at the other end through ports in said transverse sleeve wall to the interior of said cylindrical barrel portion about said metering plug, and

said metering plug having at least one tapered axial flow passage opening laterally of said plug and endwise through the end of said plug, whereby axial adjustment of said metering plug regulates fluid flow through said metering bore.

2. A valve according to claim 1 wherein:

said barrel has a valve seat about one end of said metering bore, and said sleeve has a valve face about the base of said metering plug engageable with said valve seat.