Seal

Abstract

The invention provides a seal (4, 5, 6, 7, 8) for sealing between two members (1, 3) which are mutually movable so. as to slide relative to each other. One of the members comprises a body (3) with a channel (2) formed therein. The channel (2) has a longitudinal axis and the other member (1) is receivable in the channel (2) so that the two members (1, 3) slide relative to each other in a direction parallel to the longitudinal axis. The first element (1) has at least one deformable plastics rib (4, 5, 6, 7, 8) formed on a surface thereof. The rib (4, 5, 6, 7, 8) faces the second element (3) and in use deforms on abutment with the wall of the channel (2) of the second member (3) to provide a seal between the two elements (1, 3) when they are stationary or moving relative to one another.

Description

The present invention relates to a seal and in particular to a seal useful in systems for the sterile transfer of fluids.

Validation and accountability are vital in most scientific industries and especially so in the pharmaceutical and biotechnological industries. A major challenge to these industries is the need to demonstrate accurately and reproducibly that sterility is achieved and maintained throughout production lines within a plant. This must be done in a manner which meets the stringent requirements of regulatory bodies such as the United States FDA. Acceptable standards can be difficult to be met when a substance is transferred from one sterile location to another sterile location by non direct means. Reliable and durable seal means must be employed during such transfer.

The present invention provides a seal for sealing between two members which are mutually movable so as to slide relative to each other, a first one of the elements having formed on a surface thereof facing a second of the elements at least one deformable plastics rib for contacting the second member and sealing between the two elements when they are stationary or moving relative to one another.

In a most preferred embodiment, one of the members comprises a body with a channel formed therein, the channel having a longitudinal axis and the other member being receivable in the channel so that the two members slide relative to each other in direction parallel to the longitudinal axis, a first one of the elements having formed on a surface thereof facing a second of the elements the at least one deformable plastics rib for contacting the second member and sealing between the two elements when they are stationary or moving relative to one another.

Ideally, the first one of the two elements is constructed of plastics material and the rib may be formed integrally therewith.

The rib is sufficiently deformable and flexible so that it in effect drags or wipes along the surface of the second element with which it is in contact as the two elements slide with respect to one another. A plurality of sealing ribs may be provided, axially spaced apart from one another along the path of relative movement between the parts.

The rib itself may have different shapes and configurations, any of which will be suitable provided that they are such as to provide an effective seal between the parts. For example, the rib may be formed with its free, sealing edge shaped as a U, V, W or any other suitable cross-sectional shape.

Of particular benefit is the use of such a sealing arrangement in a valve where a piston slides within a housing so as to open or close an open end of the valve. In such a case, it is advantageous to form the rib about the radially outwardly facing surface of the piston with the rib extending radially outwardly therefrom to impinge upon the interior surface of the housing.

The seal of the present invention may have use as an alternative or addition to known sealing means, such as an O-ring seal.

The invention will now be described with reference to the accompanying drawings which show, by way of example only, several embodiments of the seal according to the invention.

In the drawings:

FIG. 1 is a side elevation of a first embodiment a seal formed in a cylindrical body;

FIG. 2 is an enlarged portion of FIG. 1 showing the seal;

FIG. 3 is a side elevation of a second embodiment a seal formed in a cylindrical body;

FIG. 4 is an enlarged portion of FIG. 3 showing the seal;

FIG. 5 is a side elevation of a third embodiment a seal formed in a cylindrical body;

FIG. 6 is an enlarged portion of FIG. 5 showing the seal;

FIG. 7 is a side elevation of a fourth embodiment a seal formed in a cylindrical body;

FIG. 8 is an enlarged portion of FIG. 7 showing the seal;

FIG. 9 is a side elevation of a fifth embodiment a seal formed in a cylindrical body;

FIG. 10 is an enlarged portion of FIG. 9 showing the seal;

FIG. 11 is a perspective view of a sliding piece having one seal of the first embodiment;

FIG. 12 is an elevation of a portion of a piston having three seals of the fourth embodiment;

FIG. 13 is an enlarged sectional view of a portion of FIG. 12 showing the seals; and

FIG. 14 is a sectional elevation of a fourth embodiment of the seal used in combination with an O-ring.

Referring to FIGS. 1 to 10 there is shown a cylinder 1 slidably receivable in a circular channel 2 of a body 3. A seal member according to the invention is provided in a form of deformable ribs 4, 5, 6, 7, 8 of FIGS. 2, 4, 6, 8, and 10 respectively formed around the external surface of the cylinder 1. The rib 4 has a U-shape in cross section, the ribs 5, 7 and 8 are V-shaped in cross-section and the rib 6 is W-shaped in cross-section. The diameter of the cylinder 1 is smaller than the diameter of the channel 2 whereas the most peripheral region 9 of the surface of the rib 4, 5, 6, 7, 8 projects beyond the external surface 1 a of the cylinder 1 so that the diameter of the most peripheral region 9 is greater than the diameter of the channel 2. The cylinder 1 is made of a plastics material and the rib 4, 5, 6, 7, 8 is formed integrally with the cylinder. Other means of forming the rib on the cylinder are also possible.

In use, when the cylinder 1 is loaded into the channel 2, the most peripheral region 9 of the surface of the rib 4, 5, 6, 7, 8 abuts the wall of the channel 2 and deforms in order to permit the cylinder 1 to enter the channel 2. The abutment is sufficiently close and tight that a seal is formed between the wall 10 and the rib 4, 5, 6, 7, 8. This seal remains intact during subsequent movements of the cylinder 1 along the channel as the deformable rib 4, 5, 6, 7, 8 drags or “wipes” along the wall of the channel 2.

FIG. 11 shows a cylinder 1 in perspective having one rib 5.

FIGS. 12 and 13 show an end portion of a piston 12 for use in a valve for sterile transfer of fluids. Such a piston is movable within a housing of the valve in order to open or close an open end of the housing. The piston 12 has three ribs 7 axially spaced apart from each other along the path of the piston in the housing.

FIG. 14 shows a rib 7 formed around the external surface of a piston 14 disposed in a channel 18 of a housing 15. The rib 7 is used in combination with an O-ring 16 received in a groove 17 of the piston 14 to provide a seal between the exterior of the piston 14 and the wall of the channel 18.

The ribs 4, 5, 6, 7, 8 have been described as formed around a cylinder 1 but of course such ribs 4, 5, 6, 7, 8 may be provided around the wall defining the channel 2 of the body 3 in order to form a seal between the external surface 1a of a cylinder 1 received in the channel 2.

The seal member of the invention is not limited to use only in a cylinder or in a circular channel and indeed can be provided around a body or around a wall of a channel of any cross-sectional shape, such as for example square or any other shape suitable to provide a seal. Neither is the seal of the invention limited to sealing between elements which slide relative to one another about a common concentric axis. Rather, the seal of the invention can be used to seal between any two surfaces which slide relative to each other. The rib will be provided substantially perpendicular to the axis substantially parallel to which the surfaces slide.

It will of course be understood that the invention is not limited to the specific details as herein described, which are given by way of example only, and that various alterations and modifications may be made without departing from the scope of the invention as defined in the appended claims.

Claims

1. A seal for sealing between two members which are mutually movable so as to slide relative to each other, a first one of the members having formed on a surface thereof facing a second of the members at least one deformable plastics rib for contacting the second member and sealing between the two members when they are stationary or moving relative to one another, and in which at least two ribs are formed on the surface of the first member so that the distance between the ribs alone the path of travel of the two members relative one another is greater than a predetermined distance of travel of the two members relative to each other along the path so as to allow one of the ribs to always remain within a predetermined area of the surface of the second member.

2. A seal as claimed in claim 1, in which the first one of the two members is constructed of plastics material and the rib is formed integrally therewith.

3. A seal as claimed in claim 1, in which the rib is sufficiently deformable and flexible so that it drags or wipes along the surface of the second member with which it is in contact as the two elements slide with respect to one another.

4. (canceled)

5. A seal as claimed in claim 1, in which a plurality of the ribs is provided, the ribs being axially spaced apart from one another along the path of relative movement between the parts.

6. A seal as claimed in claim 1, in which one of the members comprises a body with a channel formed therein, the channel having a longitudinal axis and the other member being receivable in the channel so that the two members slide relative to each other in a direction parallel to the longitudinal axis, a first one of the members having formed on a surface thereof facing a second of the members the at least one deformable plastics rib.

7. A seal as claimed in claim 6, in which an adaptor is provided between the wall of the channel and the receivable member, the adaptor comprising an endless skirt provided around a surface of one of the channel or the receivable member facing the other member, the skirt being connected to the member and being movable with the member so that mutually facing surfaces of the skirt and of the member to which the skirt is attached are spaced to define a gap therebetween, the at least one deformable plastics rib being formed around one of the mutually facing surfaces of the skirt and said other member, the skirt being sufficiently deformable and flexible in order to enable adjustment of the skirt to accommodate dimensional irregularities between the skirt and said other member when the two members are engaged so as to allow the at least one rib to seal between the mutually facing surfaces of the skirt and said other member when the two members are stationary or moving relative each other.

8. A seal as claimed in claim 7, in which the skirt comprises a free end portion and a base portion about which the skirt is connected to the member.

9. A seal as claimed in claim 7, in which the skirt is formed around the receivable member and the rib is formed around the external surface of the skirt so that in use the skirt deforms in the channel to adjust to dimensional irregularities between the external surface of the skirt and the wall of the channel to enable the rib to seal therebetween.

10. A seal as claimed in claim 7, in which the skirt is sufficiently resilient to regain its original state upon withdrawal of deformation.

11. A seal as claimed in claim 7, in which the skirt is provided about an outwardly facing surface of a piston movable within a housing of a valve for sterile transfer of fluids with the rib being formed around the external surface of the skirt.

12. A seal as claimed in claim 7, in which the skirt is provided as an attachment connectable to the member via a coupling means.

13. A seal as claimed in claim 7, in which the coupling means comprises a snap-fit arrangement between the skirt and the other member.

14. A seal as claimed in claim 7, in which the snap-fit arrangement comprises a series of alternating resiliently deformable ribs and grooves formed around each of the mutually facing surfaces of the skirt and the other member the ribs of the skirt and the other member being deformable on assembly so as to engage with the corresponding grooves of the member and the skirt.

15. A seal as claimed in claim 7, in which the skirt is formed integrally with the member by forming an endless slot in the material of the member so that the slot is defined by mutually facing endless surfaces of the skirt and the member.

16. A seal as claimed in claim 7, in which the skirt is manufactured from plastics material.

17. A seal as claimed in claim 7, in which the skirt is configured to be sufficiently resiliently deformable under a predetermined pressure range of fluid supplied into a gap between the mutually facing surfaces of the skirt and the member to which the skirt is attached, so as to deflect towards the other member thus enhancing the sealing action of the at least one rib between the skirt and the other member.