JOINT FOR DEVICE FOR METERING LIQUIDS

• US 20110027149A1
• Filed: 04/07/2009
• Published: 02/03/2011
• Est. Priority Date: 04/08/2008
• Status: Active Grant

• Current Assignee: Socorex Isba SA
• Original Assignee: Socorex Isba SA
• Inventors: Uldry, Jean-Pierre
• Granted Patent: US 8,900,526 B2
• Time in Patent Office: Days
• US Class Current: 422/501
• CPC Class Codes: B01L 2200/0605 Metering of fluids
• CPC Class Codes: B01L 2400/0478 pistons
• CPC Class Codes: B01L 3/0217 of the plunger pump type medical syringes A61M
• CPC Class Codes: F16J 15/3232 having two or more lips

Abstract

The present invention relates to a device for manually metering liquids, for example a pipette or a metering button. The device comprises a joint forming a seal between a hollow cylinder and a piston housed inside the cylinder, the piston being moved vertically so as to suck in or expel the liquid. During the metering operation, the joint remains fixed with respect to the movement of the piston and comprises parts formed by portions having dedicated geometric and mechanical characteristics which make it possible to locally optimize the functions of sliding, sealing and fastening in the cylinder.

Claims

1. A device for manually metering liquids comprising a cylinder and a piston housed inside the cylinder, with the device being arranged so as, during the metering operation, the piston moves along its axis to suck in or to expel the liquid, the device further comprising a joint housed in the cylinder and arranged so as to provide the sealing between the cylinder and the piston, wherein during the metering operation, the joint remains fixed with respect to the movement of the piston, wherein the joint comprises a first part which cooperates with the internal wall of the cylinder and which fulfils the functions of sealing the joint directly against the internal surface of the cylinder and fastening of the joint in the cylinder, and a second part which is in contact with the piston which fulfils the functions of sealing the joint against the piston and sliding between the joint and the piston, and wherein the thickness of the second part of the joint, measured at a contact point with the piston in a direction perpendicular to the piston axis from said point of contact and/or the thickness of a connection zone between the first part and the second part is chosen so that the friction force imparted by the joint pressing against the piston surface upon the movement of the piston with respect to the joint is smaller that 5 N for pipetted volume smaller than 100 ml.

3. The device according to claim 1, wherein the thickness of the second part of the joint, measured at a point of contact with the piston in a direction perpendicular to the piston axis from said point of contact and/or the thickness of a connection zone between the first part and the second part of the joint is smaller than 1 mm.

4. The device according to claim 1, wherein the joint includes at least one recess making it possible to uncouple the functions.

5. The device according to claim 1, wherein at least a part of the joint is made of a material having a Shore A hardness of less than 75.

6. The device according to claim 1, wherein the joint has an annular shape including an external part and an internal pail, with the external part being more rigid than the internal part.

7. The device according to claim 1, wherein the joint profile in radial cross-section with respect to the piston axis includes at most one axis of symmetry.

8. The device according to claim 1, constituting a pipette, a metering device for a bottle and/or a syringe.

9. The device according to claim 1, wherein the joint is made in one piece, possibly composed of several different materials.

10. The device according to claim 1, wherein the joint is arranged so as to compose at least one and preferably at least two distinct zones of contact with the piston.

11. The device according to claim 5, wherein the joint is arranged so as to form a closed space between the two contact zones and so that such closed space contains a lubricant intended to reduce the adhesion and the friction forces between the piston and the joint upon the movement of the piston with respect to the cylinder.

12. The device according to claim 1, wherein the joint is an asymmetric X-ring.

13. The device according to claim 7, wherein said first part of the joint is more voluminous and/or more rigid than said second part of the joint.

14. The device according to claim 1, wherein the joint has, in radial cross-section with respect to the piston axis, at least a part having a curved shape oriented towards the piston axis and the proximal zone of which is in contact with the piston.

15. The device according to claim 9, wherein the joint has, in radial cross-section with respect to the piston axis, a series of several parts having curved shapes and directed towards the piston axis and the proximal parts of which are in contact with the piston.

16. The device according to one of claim 9, wherein the joint is retained in the space between the internal wall of the cylinder and the piston using at least one retaining ring, openings and/or grooves.

19. The device according to claim 10, wherein the joint is retained in the space between the internal wall of the cylinder and the piston using at least one retaining ring, openings and/or grooves.

2. (canceled)

17. (canceled)

18. A device for manually metering liquids comprising a cylinder, a piston sliding in the cylinder against and under the effect of the force of a spring, and a joint housed between an internal wall of the cylinder and an external wall of the piston, wherein the joint is an annular part formed with distinct respectively peripheral and internal annular parts, with the peripheral part being arranged for a stationary fastening to said internal wall of the cylinder and the said internal wall being arranged for a continuous and sealed sliding against the external wall of the piston, with the latter being cylindrical.