Non-Return Valve for Medical Purposes in Particular for Balloon Catheters

The invention will be described in greater detail hereinafter with reference to preferred embodiments which are illustrated in the drawing in which:

FIG. 1 is a view in longitudinal section through a non-return valve according to the invention, in the closed position,

FIG. 2 shows the non-return valve of FIG. 1 in the open position,

FIG. 3 shows another embodiment in the closed position, and

FIG. 4 shows the FIG. 3 embodiment in the open position.

In the embodiment shown in FIGS. 1 and 2, the end of a hose or tube 1 which leads for example to an inflatable balloon of a catheter is pushed onto the outside periphery 2 of a valve housing 3 until it butts against a flange 4. The tube 1 can be held at the position by inherent elasticity, for example if it comprises rubber or another elastic material, but it can also be secured in position by adhesive means or retained in place by an additional clip, collar or the like. The valve housing 3 has a space 5 in its interior, which is surrounded by a peripheral wall portion 6 and which is closed off by a rigid end wall portion 7 which is formed integrally with the peripheral wall portion 6. At one end, the valve housing 3 has a conical connecting opening 8 for insertion of the conical nozzle or mouthpiece 9 of a spray or syringe 10 while at the oppositely disposed end there is a through opening 11 which is formed by the end of an axial external groove 12 in the peripheral wall portion 6. The groove 12 communicates with the space 5 inside the valve housing 3 by way of a radial bore 13, a valve opening 15 being formed at the inside periphery 14. Disposed adjacent the connecting opening 8 is an inwardly directed first abutment 16 in the form of a shallow annular bead. A second abutment 17 projects upwardly from the end wall portion 7, in the form of individual blocks which are displaced in the peripheral direction.

A slide member 18 which forms the closure member of the non-return valve is displaceable between the two abutments 16 and 17. The slide member 18 has two peripherally extending sealing lips 19 and 20 which, under the influence of radial forces which are predetermined by the dimensions of the slide member 18, with respect to the valve housing 3, bear sealingly against the inside periphery 14 of the valve housing 3. The slide member 18 has a cavity 21. A coil spring 22 engages into the cavity 21, the coil spring being supported between the blocks of the second abutment 17 on the end wall portion 7 and urging the slide member 18 into the closed position shown in FIG. 1. For the purposes of mechanically coupling it to the mouthpiece 9, the slide member 18 has an outwardly projecting pin portion 23 with a transverse groove 24 in its end. As shown in FIG. 2, the mouthpiece 9 can engage the pin portion 23 and urge the entire slide member 18 towards the second abutment 17, compressing the spring 22, whereby the non-return valve moves into its open position.

In the open position of the valve, air or another fluid which is supplied by the syringe 10 flows into the upper part of the space 5 and by way of the valve opening 15, the radial bore 13, the external groove 12 and the through opening 11, into the interior 25 of the tube 1 and thus to the location at which it is to be used or consumed.

When the mouthpiece 9 is withdrawn, the slide member 18 returns into the closed position shown in FIG. 1, under the force of the spring 22. In the closed position, both sealing lips 19 and 20 lie between the connecting opening 8 and the valve opening 15 so that the interior 25 of the tube is securely sealed off with respect to the connecting opening 8. In that respect, the pressure in the tube 1 acts in addition to the spring 22 to hold the slide member 18 in the closed position shown. Therefore, the spring 22 only needs to have a slight biasing force in the extended position shown in FIG. 1. The spring can therefore be made comparatively weak and inexpensively.

The pressure also acts in the cavity 21. The higher the pressure, the greater are the radial forces which act at least on the sealing lip 20 so as to ensure the sealing action.

The slide member 18 and the valve housing 3 are injection moulded from plastic material and then automatically assembled. For that purpose, the spring 22 and the slide member 18 only have to be pushed into the space 5 inside the valve housing. In that operation, the slide member 18 can be pushed past the first abutment 16 because that abutment is raised in an inward direction above the inside periphery 14 to such a slight degree that the usual elasticity of the plastic materials of the valve housing 3 and/or the slide member 18 is sufficient to produce the deformation required for that purpose. The plastic materials are not subject to high requirements. Therefore, it is possible to carry out a high-speed injection moulding manufacturing operation, thus giving very low cost levels. The plastic material used may be for example a polyolefin or the like. Manufacture is therefore simple and inexpensive. The non-return valve can therefore be supplied as a cheap throw-away article.

In the embodiment illustrated in FIGS. 3 and 4, the same reference numerals are used to denote corresponding parts, but increased by 100. Essentially the differences are that axial grooves 112 which are formed on the inside periphery 114 are provided as the valve opening 115, which grooves 112 can also be extended in the form of grooves 126 in the end of the arrangement. The through opening 111 is disposed at the centre of the end wall portion 107.

When in this case the slide member 118 is displaced from the closed position shown in FIG. 3 into the open position shown in FIG. 4, the air or the fluid flows only in the space 105 inside the valve housing 103. The axial grooves 112 cannot become obstructed from the outside.

The non-return valve may be used for a very wide range of medical purposes which involve seeking to achieve a sound and reliable closure of a space which is under an elevated pressure and which is to be filled by means of a syringe. In particular, the above-mentioned space may be a balloon which is disposed at the front end of a catheter tube and which is connected to the non-return valve by way of a passage additional to the catheter tube and which serves for fixing the catheter tube in position after it has been introduced into the human body. For the purposes of emptying the above-indicated space, the slide member 18 only needs to be moved with the mouthpiece 9 into the open position, whereupon the air or the fluid escapes or can be sucked away with the syringe.