APPARATUS FOR ADMINISTERING A LIQUID TO PATIENTS

Abstract: This invention provides an apparatus, for administering liquid into the body, including a feeder tube (1) into which liquid enters at an upper part (2) and from which liquid flows out at a lower part through part through an exit opening (3). In order to shut off the system before the liquid supply is exhausted a floatable valve (5) is provided which floats in an upper position so long as there is plenty of liquid in the feeder tube (1) but which moves to a lower position to close the exit opening (3) before the liquid level in the feeder tube (1) falls to a dangerously low level. The exit opening (3) is preferably provided with an improved tube (4,C) shaped projection to control the movement of the valve member (5,A).

Description: "Improvements in or relating to adminstering liquid to patients" This invention is concerned with the provision of improved safety means for use in the administration of liquid to the body of a patient. There is currently on the market a method of administering liquid directly into the body, known under the common name of a 'Burette Set'. Such administration devices are available from several of the major Pharmaceutical Companies. That device is used to give a large volume of infusion liquid over a period of time and consists of a plastics tube of approximately li" diameter and some 6" in length which is graduated along its length. The liquid in question enters the top of the tube and is administered from the base of the tube through an infusion line into the body. The graduations on the tube monitor the dosage. It is of vital importance that when the liquid approaches the bottom of the tube there is a known cut-off point when the liquid will cease to flow and air will not enter the line as air in any infusion line is a major hazard. There are several designs of valve at the base of the tube for ensuring that the liquid cuts off at the correct level and does not admit air. According to the present invention we provide apparatus, for administering liquid into the body of a patient, comprising a feeder tube into which liquid enters at an upper part and from which liquid flows out at a lower part through an exit opening, characterised by the provision of a floatable valve member which floats in an upper position so long as there is adequate liquid in the feeder tube but which moves to a lower position to close the exit opening when the liquid level falls to a predetermined position. The valve may be made of any suitable material e.g. plastics, rubber or a rubber plastics combination or any other preferably flexible and resilient material. The invention also includes apparatus for administering liquid into the body of a patient, comprising a feeder tube into which liquid enters at an upper part and from which liquid flows out at a lower part through an exit opening characterised in that the exit opening of the feeder tube is in a cup shaped projection forming part of the tube and that the floatable valve member has a depending-valve closing part operable within the cup-shaped projection forming the exit opening of the tube, the arrangement being such that the floatable valve member floats in an upper position so long as there is adequate liquid in the feeder tube but which moves to a lower position to close the exit opening when the liquid level falls to a predetermined position. In the accompanying drawings given by way of example, Figure 1 is a side view of one form of apparatus, and Figures 2, 3 and 4 are detail views. In Figure 1 infusion liquid enters a burette tube 1 at the top 2 and leaves the tube at an exit 3 at the bottom. The exit is surrounded by projecting tubular wall 4 and a floatable valve member 4 cuts of the liquid flow at the level 6. Figure 2 shows a floatable plastics valve A with a polymer sealing liner 3, the tubular wall 4 being shown at C. The valve member is shown in its mid position. when the tube is full of liquid the valve will be in its top position with a ridge 7 engaging a ridge 8. As the liquid level falls the valve member will move down until the liner seals the opening. The shape of valve stem 9 is shown in Figure 2A. In Figure 2 the valve stem engages with the inside of the projection. In Figure 3 the arrangement is similar to Figure 2 except that the valve stem engages with the outside of the projection. Figure 4 shows a modification. The underlying idea of the invention is therefore to provide the exit hole with a surrounding projecting wall which forms a short upwardly projecting inner tube and to provide the inner tube with a floatable valve member which occupies an upper position to keep the exit open when there is sufficient liquid in the main tube and to move to a lower position to close the exit when the liquid level e.g. any liquid medicament falls to a predetermined level. It will therefore be understood that all the drawings referred to above are variations of the same principle whereby a plastics plug or over cap is fitted with a sealing polymer, probably rubber, liner and the whole assembly either clips into, or over, a protrusion from the bottom cap of the tube. This gives a more simply assembled device than the somewhat complex arrangements currently available. Again the principle in all three of the above described modifications is that the clipped-on preferably plastic and rubber combination will float while there is liquid in the tube and will sink as the liquid level approaches zero and will seal when the rubber disc or liner meets the upward projection from the base of the tube. This sealing will be designed to occur before air is allowed in. The clip on feature has the further advantage of limiting the upward movement of the valve in each of the three cases so that when there is liquid in the tube the valve is only allowed to float upwards a certain distance. This is an improvement over many of the existing devices which can float to the top of the liquid and suffer from problems with sticking on the sides of the tube as the liquid level lowers, and our design should ensure accurate locating and sealing at the required point. A second embodiment of the invention is illustrated by way of example in Figures 5 to 8 in which Figure 4 is a sectional view of a floating valve in position in the tube, Figure 6 is a planview of Figure 5, Figure 7 is a sectional view of the valve head, and Figure 8 is a planview of Figure 7. In the drawings, Figures 5 to 8 , a hollow feeder tube 21 has a downwardly extending cup-shaped projection 22 at the bottom 23 with a central exit opening 24 closed by means of a moulded or like plug 25 into which a thin hollow cannular 26 is fitted. The cannular 26 is open at the top and bottom so that liquid within the feeder 1 can flow into the cannular, the upper end of which projects at 27 above the top of the plug 25. A floatable valve member 28 is disposed above the cup-shaped projection and the member 28 has a depending valve closing part 29 provided with a rubber or other suitable flexible resilient or the like sealing member 30. The outer diameter of the member 28 is less than the inner diameter of the tube 1 so that there is an annular space 31 between the members 28 and the tube 21. In addition the member 28 has holes 32 leading from the top of the member 8 to an undercut portion 33 at the bottom of member 28. The member 28 also has peripheral recesses 34 to co-operate with spaced apart projections 35 on the inside of the tube 21. The valve member 28 is assembled within the tube 21 by passing the member 28 down from the top of the tube in such a way that the recesses 34 can pass the projections 35. The member 28 is the angularly displaced so that in operation rising of the member 28 iscontrolledby the projections 35. The member 28 is then angularly displaced so that in operation rising of the member 28 is controlled by the projections 35. When the valve member is in its down position the sealing member 30 is resting on the top of the cannular 26 so that the exit from the tube 21 is closed. If liquid be fed into the tube 21 the valve member will rise until the top of the member 28 contacts the projections 35 so that liquid can flow down the holes 32 and through the space 31 into the cup-shaped projection 22 and from there into the cannular 26 because rising of the member 28 has moved the sealing member 30 away from the top of the cannular. In the first embodiment shown in Figures 1 to 4 the closing operation is effected over a relatively large area while in this second embodiment the closing operation is effected over a very small area ie between the sealing member 30 and the cannular 26 with apparatus of the same or greater mass than before, The small area sealing has advantages in certain cases because the possibility of leakage is reduced. If the liquid level in the tube 21 falls below a safe level the valve member 28 will return to its down position, the member 30 will seat on the top of the cannular 26 and flow of liquid into the cannular will stop. We prefer that the valve member 28 shall be made of a suitable plastics material and that the sealing member 30 shall be made of rubber so that a rubber to cannular seal is achieved. However, using the same principle detailed above, an alternative method of obtaining a seal is possible with this embodiment of the invention whereby member 30 is a continuation of valve closing part 29 with a conical rather than a flat tip. This conical tip locates, when the valve is closed, with a conical recess in the plug 25 and the cannular 26 will then not project above the base of this conical recess. It will also be understood that the member 28 may have an uninterrupted periphery which can simply be pushed over the projections 35 to locate the member 28.

Claims: Claims 1. Apparatus, for administering liquid into the body of a patient, comprising a feeder tube into which liquid enters at an upper part and from which liquid flows out at a lower part through an exit opening characterised by the provision of a floatable valve member which floats in an upper position so long as there is adequate liquid in the feeder tube but which moves to a lower position to close the exit opening when the liquid level falls to a predetermined position. 2. Apparatus according to Claim 1 wherein the exit opening of the feeder tube has an upward tube shaped projection which controls the movement of the valve member. 3. Apparatus according to Claim 1 or 2 wherein the valve member is made of plastics material with a polymer sealing line. 4. Apparatus according to Claim 2 wherein the valve member has a valve stem with an outwardly projecting ridge to engage below an inwardly projecting ridge on the tube shaped projection when the valve member is in its upper position. 5. Apparatus according to Claim 2 wherein the valve member has a skirt to surround the top of the tube shaped projection, the skirt having an inwardly projecting ridge to engage with an outwardly projecting ridge on the tube shaped projection when the valve member is in its upper position. 6. Apparatus according to Claim 1 wherein the exit opening of the feeder tube is in a cup-shaped projection and the floatable valve member has a depending valve closing part operable within the cup shaped projection forming the exit opening. 7. Apparatus according to Claim 1 wherein the hollow feeder tube has a downwardly extending cup-shaped projection at the bottom with a central exit opening closed by means of a moulded or like plug into which a thin hollow cannular is fitted, the cannular being open at the top and bottom so that liquid within the feeder tube can flow into the cannular, the upper end of which projects above the top of the plug. 8. Apparatus according to any of the preceding claims wherein the outer diameter of the valve member is less than the inner diameter of the tube so that there is an annular space between the valve member and the tube and wherein the valve member has holes leading from the top of the member to an undercut portion at the bottom, and peripheral recesses to co-operate with spaced apart projections on the inside of the tube. 9. Apparatus, for administering liquid into the body of a patient, comprising a feeder tube into which liquid enters at an upper part and from which liquid flows out at a lower part through an exit opening characterised in that the exit opening of the feeder tube is in a cup-shaped projection forming part of the tube and that the floatable valve member has a depending valve closing part operable within the cup-shaped projection forming the exit opening of the tube, the arrangement being such that the floatable valve member floats in an upper position so long as there is adequate liquid in the feeder tube but which moves to a lower position to close the exit opening when the liquid level falls to a predetermined position. 10. Apparatus, for administering liquid into the body of a patient substantially as hereinbefore described with reference to either of the embodiments illustrated in the accompanying drawings.

Inventors: STAFFORD, PETER WILLIAM
Applicants: WEST PHARMARUBBER LIMITED
Application year: 1983
Main classification: A61M5
IPC codes: A61M5