WO2005053783A1

WO2005053783A1 - Check valve

Info

Publication number: WO2005053783A1
Application number: PCT/GB2004/005022
Authority: WO
Inventors: Kevin Chilvers
Original assignee: Bespak Plc
Priority date: 2003-11-27
Filing date: 2004-11-29
Publication date: 2005-06-16
Also published as: GB2408561B; GB0327611D0; GB2408561A

Abstract

A check valve comprises a body (1), defining a bore, having a first open end adapted for connection with a dispensing apparatus and a second open end adapted for connection with a delivery apparatus; a core (2) slidable in the bore between a closed position and an open position; sealing means (5), for sealing between the body and the core when the core is in the closed position, so as to prevent flow of fluid between the first and second open ends; and spring means (4) biasing the core into the closed position. The core is a one-piece core having a first portion extending towards the first open end of the body, a second portion extending towards the second open end of the body and a flange intermediate the first and second portions. A distal end of the first portion of the core comprises one or more passageways for allowing fluid communication between a dispensing apparatus, to which the check valve is connected in use, and the bore when the dispensing apparatus is brought into direct engagement with the distal end of the first portion of the one-piece core to propel the core from the closed position to the open position.

Description

CHECK VALVE

This invention relates to check valves. In particular, it relates to medical check valves for use in the insertion or removal of fluids (being liquids or gases) into or out of animals or humans. More particularly, the invention relates to a check valve used for the inflation or deflation of a cuff or balloon on a medical device used either internally or externally of the human or animal body.

Check valves in general are known in the art. One example is shown in Figure 1. This check valve comprises a body 1 housing a core 2, a spring 4, a seat 5 and an adaptor 6. The body 1 is designed to be connected to a syringe from the rearward side (left hand side as shown) , and to a tube on the forward side (right hand side as shown) as described below. The valve provides a seal at the end of the tube, whilst also allowing fluid to be inserted or removed from or into the syringe.

The hollow body 1 comprises a cap lc and a generally cylindrical part, with a first portion la of smaller cross- sectional area and a second portion lb of larger cross- sectional area. A flange 7 extends inwardly from the interior surface of the body 1 and defines an aperture 23 which delineates the first portion la from the second portion lb. The forward facing surface of the flange 7 is provided with a rirα 25. The second portion lb is at a forward end of the body 1. The first portion la is at a rear end of the body 1. The cylindrical part la, lb of the body 1 is hollow and comprises an open end 8 at the rear end of the body 1 and an open end 22 at the forward end of the body 1. A continuous bore 20,21 runs from open end 8 to open end 22 via aperture 23. The diameter of bore 20 is smaller than that of bore 21. The cap lc is received in bore 21 in the open end 22 of the body 1 in a sealing manner. A through bore 24 is formed in the cap lc allowing fluid to pass through the cap lc. The rear-most portion of bore 20 is tapered with a Luer taper 26 to BS EN 20594. The inner diameter of bore 20 thus slightly decreases towards the second, portion lb of the body 1. The core 2 is contained within the body 1 and comprises a generally cylindrical member having an enlarged-diameter mid-portion 30. The core 2 is symmetrical about a transverse axis at its midpoint. The enlarged mid-portion 30 is provided with an outwardly-directed flange 10. The core 2 is further provided with an annular seat 5 which is abutted against the rearwardly facing surface of the flange 10. The internal diameter of the seat 5 is chosen so as to form an interference fit on the enlarged mid-portion 30 so that in use the seat 5 moves with the mid-portion 30. The core 2 is located in bore 20, 21 with the flange 10 in bore 21. The core 2 is biased rearwardly by means of a spring 4 which extends between cap lc and a forward-facing surface of flange 10. The spring 4 biases the seat 5 into sealing contact with the rim 25 of the flange 7. End portions 2a and 2b of the core 2 are provided with flutes 14 running longitudinally from the distal ends of the core 2 to the enlarged mid-portion 30. The adaptor 6 is mounted on the rearward end of end portion 2a of the core 2 within bore 20. The adaptor 6 comprises a cylindrical body 60 having a closed rear end 61 and an open forward end 62 which is received over the distal end of end portion 2a. The closed rear end 61 comprises an aperture 11. The open end 62 is provided with a outwardly flared rim 12.

In the use of the known valve, a nozzle of a Luer syringe is inserted into bore 20. The nozzle is of a diameter such that as it is inserted, the Luer taper 26 ensures that the syringe seals in a fluid-tight manner with the body 1. As the syringe nozzle is pushed forwards it contacts the closed end 61 of the adaptor 6 with the aperture of the syringe nozzle at least partially aligned with aperture 11 in the adapter 6. Movement of the syringe propels the adaptor 6, core 2 and seat 5 forwardly, against the biasing of the spring 4. As the core 2 moves forwardly, the seat 5 and flange 10 lose contact with rim 25 breaking the seal formed therebetween. The syringe is then enabled to dispense fluid through the check valve. The dispensed fluid passes through the aperture 11 into the flutes 14 of the end portion 2a of the core 2. The fluid is forced along the flutes 14 and then through aperture 23 and between the flange 7 and seat 5 into bore 21. The fluid is then free to move along bore 21 and through the bore 24 of cap lc. The fluid then passes into a connecting tube (or other delivery device attached to the check valve) to flow into the human or animal to inflate a cuff or balloon on a medical device.

When the syringe is withdrawn from the check valve, the spring 4 urges the core 2 rearwardly until the seat 5 and flange 7 contacts with rim 25, resealing the valve. The core 2 may also be urged rearwardly by the back pressure from the delivery tube. Deflation of a cuff or balloon using the check valve is also possible by retraction of the syringe plunger whilst the syringe is still engaged in the check valve.

However, the valve discussed above has the disadvantage that an adaptor is required to enable operation by the syringe. This complicates the device and increases its production cost. The adaptor may increase the chance of the device becoming jammed or clogged after use. According to the present invention, there is provided a check valve comprising: a body defining a bore having a first open end adapted for connection with a dispensing apparatus and a second open end adapted for connection with a delivery apparatus; a core slidable in the bore between a closed position and an open position; sealing means for sealing between the body and the core when the core is in the closed position so as to prevent flow of fluid between the open and closed ends; spring means biasing the core into the closed position; wherein the core is a one-piece core having a first portion extending towards the first open end of the body, a second portion extending towards the second open end of the body end and a flange intermediate the first and second portions; wherein a distal end of the first portion of the core comprises one or more passageways for allowing fluid communication from a dispensing apparatus, to which the check valve is attached in use, into the bore when the dispensing apparatus is brought into direct engagement with the distal end of the first portion of the one-piece core to propel the core from the closed to the open position.

For a better understanding of the invention, embodiments will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a longitudinal section of a known prior art check valve; Figure 2a is a longitudinal section of a first embodiment of the core of the check valve of the present invention; Figure 2b is an end elevation of a first embodiment of the core of the check valve of the present invention; Figure 3a is a longitudinal section of a second embodiment of the core of the check valve of the present invention; Figure 3b is an end elevation of a second embodiment of the core of the check valve of the present invention; Figure 4a is a longitudinal section of a third embodiment of the core of the check valve of the present invention; Figure 4b is an end elevation of a third embodiment of the core of the check valve of the present invention; Figure 5a is a longitudinal section of a fourth embodiment of the core of the check valve of the present invention; Figure 5b is a first end elevation of a fourth embodiment of the core of the check valve of the present invention; Figure 6a is a longitudinal section of a body of the check valve of the present invention for use with the fourth embodiment of core; Figure 6b is an end elevation of the body of the check valve of Figure 6a; Figure 6c is a second end elevation of the body of Figure 6a; Figure 7 is a longitudinal section of a fourth embodiment of the check valve of the present invention.

A first embodiment of the check valve of the present invention is shown in Figures 2a and 2b. The valve comprises a body 1 of the type described with reference to Figure 1.

The core 202 of trie valve is contained axially within the body 1 as before. The core 202 comprises a generally cylindrical member having a flange 210 part-way along its length. End portions 202a and 202b are defined on either side of flange 210. End portion 202a is at the rear of the core and comprises, at its distal end, a cruciform section 214. The cross-section of the cruciform section 214 shown in Figure 2b, comprises four equal-length arms 217. The radially outer surface of each arm 217 is of convex curvature . The cruciform section 214 allows good fluid flow between the syringe and the body 1 between the arms 217. The cruciform section 214 has a relatively small central section surrounded by the four arms 217, permitting a high rate of fluid flow around the core 202. The cruciform section 214 is also relatively simple to mould.

The cruciform section 214 is integrally formed with the end portion 202a of the core 202. The end portion 202a is of the same external diameter as the arms 217 of the cruciform section 214. The cruciform section 214 only extends part-way along the end portion 202a towards the flange 210.

The forward end portion 202b of the core 202 is cylindrical, and integrally formed with the flange 210. The forward section 202b is cylindrical, with a smaller diameter than that of the cruciform section 214 and end portion 202a. The forward end portion 202b is shorter than the rear end portion 202a.

The end portion 202a is contained in the first portion la of the body, and the flange 210 and end portion 202b of the core 202 are contained in the second portion lb of the body 1.

The flange 210 is provided with a seat 205 on its rearward-facing surface which forms an interference fit with the external diameter of end portion 202a. In use, the check valve operates in a similar manner to that described previously. The nozzle of a Luer syringe is inserted into the bore 20, and engages with the Luer taper 26 of the bore 20 to form a fluid tight seal. However, the nozzle directly contacts the cruciform section 214 at the distal end of the core 202a. The nozzle contacts against the arms 217 of the cruciform section 214 to propel the core 202 forwardly, the seat 205 and flange 210 losing contact with rim 25 breaking the seal formed therebetween. The arms 217 define channels between them for allowing flow of fluid. The aperture in the nozzle of the syringe is such that at least part of the aperture will be positioned adjacent to at least part of a channel between the arms 217. Hence fluid forced from the syringe flows through the nozzle of the syringe and directly into the channels between the arms 217. The fluid continues along the cruciform section 214 until the cylindrical section of the core 202a. The fluid is then forced around the cylindrical section 202a, around the flange 210, around the section 202b and out of the cap lc. The fluid then passes into a delivery tube to flow into a cuff or balloon in the human or animal. The valve reseals in the same manner as the known valve. Deflation of the cuff or balloon using the check valve is also possible by retraction of the syringe plunger whilst the syringe is still engaged in the check valve. A second embodiment of the check valve according to the present invention is shown in Figures 3a and 3b. The second embodiment is similar to the first embodiment except for the configuration of the rear end portion. The end portion 302a at the rear is again provided with a cruciform section 314. In this embodiment the cruciform section 314 extends at the whole length of the end portion 302a from the distal end to the flange 310. This embodiment allows the fluid to flow along the channels between the cruciform arms 317 all the way to the flange 310.

The use of the second embodiment is similar that of the first embodiment. The only difference is that the fluid from the syringe can flow in the cruciform section 317 from the distal end of section 314 until the flange 310.

A third embodiment of the check valve according to the present invention is shown in Figures 4a and 4b. The third embodiment is similar to the first embodiment except for the relationship between the core and the seat. In this embodiment the core 402 is identical to core 202 of the first embodiment. The seat 405, however, is formed as a co- moulding directly on core 402 rather than being a separate component.

The use of the third embodiment is similar to that of the first embodiment. The movement of the core 402 causes the seat 405 to contact the rim 25 as before to form the seal .

A fourth embodiment of the check valve according to the present invention is shown in Figures 5a, 5b, 6a, 6b, 6c and 7. The fourth embodiment is similar to the third embodiment and also comprises a co-moulded seat 505. The flange 510 is frustro-conical in form having an angled surface 518 which is rearwardly directed. The seat 505 is formed as a co- moulding in the angled surface 518. The flange 507 of the body, is also frust ro-conical such that its forward surface matches and meets fully the angled rear face of the seat 505 in use. This provides an improved seal between the seat 505 and body 1. This embodiment also has the advantage that as the core 502 moves rearwardly as the syringe nozzle is being withdrawn, the angled surface 518 will assist the core 502 in centring in the body 1. This ensures that the seat 505 is centred on and securely contacts the flange 507 around the entire circumference of the check valve, to provide a fluid tight seal. The bore 520 is tapered with a Luer taper 526. The inner diameter of bore 520 thus slightly decreases towards the second portion 501b of the body 501.

The use of the fourth embodiment is the same as that of the second embodiment. The frustro-conical seat 505 and flange 507 contact to form the seal. Whilst above the cylindrical body 1 is circular in cross-section, it can have many cross-sectional shapes.

The cruciform section 14 has been described as having four equal arms 17, however, any number of arms could be provided to form channels to allow the passage of fluid. The arms must extend sufficiently far in a radial direction to ensure that they can contact the nozzle of an inserted syringe. In alternative embodiments, the end portions

202a, 302a, 402a, 502a of the respective cores may have non-cruciform sections. In particular, the end portion 202a, 302a, 02a, 502a may be provided with a single strip or slot at the respective distal end thereof. Further, the single strip or slot extends through, or through at least part of, the end portion 202a, 302a, 402a, 502a from the distal end to the flange. Preferably, the single strip or slot is provided at or around a diameter of the end portion

202a, 302a, 402a, 502a, or in a substantially central location thereof. When the end portion 202a, 302a, 402a, 502a is provided with a single strip, fluid can flow in channels to either side of the strip - and between the strip and the inside walls of the end portion 202a, 302a, 402a, 502a - towards the flange. Preferably, the outer surface of the strip is of convex curvature.

When the end portion 202a, 302a, 402a, 502a is provided with a single slot, fluid can flow in a single channel, between the inside walls of the slot, towards the flange.

The aperture of the nozzle of the syringe is, preferably, correspondingly-shaped to, and/or positioned in the locality of, the channel (s) formed by the above-mentioned strip and slot embodiments of the core.

The core and body can be formed of any suitable engineering plastic such as polyester, nylon, acetal, polyethylene (PE) , polypropylene (PP), polycarbonate (PC), polybutylene terephthalate (PBT) , acrylonitrile-butadiene- styrene (ABS) , polyvinyl chloride (PVC) , or similar. The seat of the core may be formed from any suitable material having acceptable performance characteristics. Preferred examples include nitrile, EPDM and other thermoplastic elastomers, butyl and neoprene.

The above description refers to the check valve for use with fluid, and it is re-iterated that the fluid may be a gas (for example air) or a liquid. The check valve may also be used to deliver or remove fluids directly to or from a human or animal body.

Claims

CLAIMS :

1. A check valve comprising: a body defining a bore having a first open end adapted for connection with a dispensing apparatus and a second open end adapted for connection with a delivery apparatus; a core slidable in the bore between a closed position and an open position; sealing means for sealing between the body and the core when the core is in the closed position so as to prevent flow of fluid between the first and second open ends; spring means biasing the core into the closed position; wherein the core is a one-piece core having a first portion extending towards the first open end of the body, a second portion extending towards the second open end of the body and a flange intermediate the first and second portions; wherein a distal end of the first portion of the core comprises one or more passageways for allowing fluid communication between a dispensing apparatus, to which the check valve is connected in use, and the bore when the dispensing apparatus is brought into direct engagement with the distal end of the first portion of the one-piece core to propel the core from the closed position to the open position.

2. The check valve as claimed in claim 1 wherein the diameter of the first portion is greater than the diameter of the second portion.

3. The check valve as claimed in claim 1 or claim 2 wherein the length of the first portion is greater than the length of the second portion.

4. The check valve as claimed in any one of claims 1 to 3 wherein at least the distal end of the first portion of the core comprises a cruciform cross-section.

5. The check valve as claimed in claim 4 wherein the distal end of the first portion of the core and a part of the first end of the core comprises a cruciform cross- section.

6. The check valve as claimed in claim 4 wherein the first portion of the core comprises a cruciform cross-section extending from the distal end to the flange.

7. The check valve as claimed in any one of claims 4 to 6 wherein the cruciform section comprises four arms.

8. The check valve as claimed in any one of claims 4 to 7 wherein the diameter of cruciform is the same as the diameter of a remainder of the first end portion.

9. The check valve as claimed in any one of claims 1 to 3 wherein at least the distal end of the first portion of the core comprises a single strip or slot.

10. The check valve as claimed in claim 9 wherein the single strip or slot extends through at least part of the first portion of the core.

11. The check valve as claimed in claim 9 or claim 10 wherein the single strip or slot extends from the distal end to the flange.

12. The check valve as claimed in any of claims 9 to 11 wherein the single strip or slot is located at or around a diameter of the first portion, or in a substantially central location thereof.

13. The check valve as claimed in any preceding claim wherein the sealing means comprises a seat which seals, in the closed position, between the flange and the body.

14. The check valve as claimed in any preceding claim wherein the flange comprises a frustro-conical portion.

15. The check valve as claimed in claim 14 wherein the seat is formed on or rests against, in use, an angled face of the frustro-conical portion.

16. The check valve as claimed in any proceeding claim wherein the flange and seat are co-moulded.

17. The check valve as claimed in any proceeding claim wherein the body is formed of a material selected from polyester, nylon, acetal, polyethylene (PE) , polypropylene (PP) , polycarbonate (PC), polybutylene terephthalate (PBT), acrylonitrile-butadiene-styrene (ABS) or polyvinyl chloride (PVC) .

18. The check valve as claimed in any proceeding claim wherein the sealing means is formed of a material selected from nitrile, EPDM, thermoplastic elastomers, butyl or neoprene .

19. The check valve of any one of the preceding claims wherein the first open end of the body has a Luer taper to tightly receive a nozzle of a Luer syringe.

20. The check valve of any one of the preceding claims wherein the biasing means is a coil spring aligned co-axially with the core and with the body.

21. The check valve of any one of the preceding claims wherein the dispensing apparatus is a syringe.

22. The check valve of any one of the preceding claims wherein the delivery apparatus is a catheter tube.

23. A check valve substantially as hereinbefore described with reference to and as shown in Figures 2 to 7 of the accompanying drawings .