Bubble Shaped Membrane and Use of Such Membrane in a Device

1 . A membrane ( 17 ) completely covering an opening ( 13 ) giving access to a space in a device which membrane ( 17 ) is made of an elastic material penetrable by a needle, the membrane ( 17 ) is fastened around the opening ( 13 ) and the membrane ( 17 ) protrudes from the opening ( 13 ) and forms an air filled volume in front of the opening ( 13 ) which air filled volume can be reduced in size when a pressure is put on the membrane ( 17 ) from the outside, the inner surfaces of the membrane ( 17 ) define a passage ( 17 a ) at the first closed end of the membrane ( 17 ) through which a needle ( 19 ) can pass and the second end of the membrane ( 17 ) is adapted to attach the membrane ( 17 ) to a holding part ( 61 ), characterized in that the walls of the membrane ( 17 ) have a thickness and shape of the chosen membrane material making it possible, to maintain the protruding shape in a use position without the outer surfaces of the membrane ( 17 ) being supported with walls of rigid material.

2 . A membrane according to claim 1 , wherein the second end of the membrane ( 17 ) has an internal opening ( 17 b ) fitting around the outer contour of a protruding part ( 61 a ) on the holding part ( 61 ) and that the membrane ( 17 ) is fastened to the holding part ( 61 ) by interference fit.

3 . A membrane according to claim 1 or 2 , wherein the membrane ( 17 ) is supported with walls of a rigid material on the inner surfaces of the membrane ( 17 ) e.g. in the form of a penetrating needle.

4 . A membrane according to claim 1 , 2 or 3 , wherein the cross-section of the air-filled volume in the passage ( 17 a ) is smaller than 2 ·[max cross-section of the opening ( 13 )].

5 . A membrane according to any preceding claim, wherein the membrane ( 17 ) has a constant or decreasing outer cross-section from where the membrane ( 17 ) is attached to the device and to the proximal end, and the passage ( 17 a ) is formed by increasing the thickness of the walls of the membrane ( 17 ) at the proximal end of the membrane ( 17 ) thereby reducing the inner air-filled cross-section of the membrane ( 17 ).

6 . A membrane according to any preceding claim, wherein the properties of the material forming the membrane ( 17 ) forming folding sections and making it possible to predict how the air filled volume is reduced when subjected to an external pressure.

7 . A membrane according to any of the preceding claims, wherein the membrane ( 17 ) can be penetrated by a pointy needle.

8 . A membrane according to any of the preceding claim, wherein the material of the membrane ( 17 ) positioned closest to the device has the thickness b 1 and has the form of a hollow truncated cone or a cylinder and the material positioned furthest away from the device has a thickness b 2 and has the form of a hollow cylinder which is closed at the end opposite the device, and b 2 >b 1 .

9 . A membrane according to claim 8 , wherein a part of the membrane ( 17 ) positioned between the material closest to the device having the thickness b 1 and the material positioned furthest away from the device having a thickness b 2 , has a thickness varying from b 1 to b 2 .

10 . A membrane according to claim 8 or 9 , wherein b 2 ≧1.5·b 1 .

11 . A membrane according to any of the claims 3 - 7 , wherein b 2 <b 1 and the distance between the rigid material supporting the inner surfaces of the membrane ( 17 ) and the inner surfaces of the membrane ( 17 ) is less than 0.5 mm.

12 . A device comprising

a membrane ( 17 ) according to any of the claims 1 - 11 ,

a base part which base part comprise a surface plate ( 1 ), fastening means which fasten the base part to a subject, a fluid path ( 3 ) having at least two openings ( 12 , 13 ): an inlet and an outlet for fluid, where one opening ( 13 ) is protected by the membrane ( 17 ) and the second opening during use connects to a penetrating part ( 7 ) transferring fluid to and/or from the subject in which it is inserted.

13 . A device according to claim 12 , wherein the opening ( 13 ) is provided at the end of a needle ( 19 ) which needle ( 19 ) is fastened unreleasably to the device and the needle ( 19 ) is placed in the air filled volume inside the membrane ( 17 ) and during periods where no pressure is put on the membrane ( 17 ) the part of the needle ( 19 ) extending into the air filled volume is completely surrounded by air.

14 . A device according to claim 13 , wherein the needle ( 19 ) during periods where pressure is put on the membrane ( 17 ) extends through the membrane ( 17 ) and protrudes from the outer surface of the membrane ( 17 ).

15 . A device according to claim 12 , 13 or 14 , wherein the needle ( 19 ) is a pointy needle.

16 . A device according to claim 12 , 13 , 14 or 15 , wherein the penetrating part ( 7 ) comprises a cannula ( 22 ).

17 . A kit comprising a device comprising a membrane according to any of the claims 1 - 11 and a unit adapted to be joined to the device assuring a sterile transfer of fluid between the device and the joined unit.