Piston seal

• US 10,675,412 B2
• Filed: 09/11/2012
• Issued: 06/09/2020
• Est. Priority Date: 09/15/2011
• Status: Active Grant

• Current Assignee: Oxford Nanopore Technologies Limited
• Original Assignee: Oxford Nanopore Technologies Limited
• Inventors: Jones, Anthony, Upsdell, Jonathan
• Primary Examiner(s): Lopez, F Daniel
• Assistant Examiner(s): Quandt, Michael
• Application Number:
  US14/344,463
• Publication Number:
  US 20140377108A1
• Time in Patent Office: 2,828 Days
• Field of Search: 92240, 92241, 92249, 92254
• CPC Class Codes: A61B 17/8822 characterised by means facilitating expulsion of fluid from the introducer, e.g. a screw pump plunger, hydraulic force transmissions, application of vibrations or a vacuum
• CPC Class Codes: A61M 2205/0222 Materials for reducing friction
• CPC Class Codes: A61M 2207/00 Methods of manufacture, assembly or production
• CPC Class Codes: A61M 5/145 using pressurised reservoirs, e.g. pressurised by means of pistons
• CPC Class Codes: A61M 5/31513 Piston constructions to improve sealing or sliding
• CPC Class Codes: A61M 5/31515 Connection of piston with piston rod
• CPC Class Codes: A61M 5/31528 by means of rotational movements, e.g. screw-thread mechanisms
• CPC Class Codes: A61M 5/31586 performed by rotationally moving or pivoted actuator, e.g. an injection lever or handle
• CPC Class Codes: B29L 2031/26 Sealing devices, e.g. packaging for pistons or pipe joints
• CPC Class Codes: B29L 2031/7544 Injection needles, syringes
• CPC Class Codes: F04B 13/00 Pumps specially modified to deliver fixed or variable measured quantities
• CPC Class Codes: F04B 17/03 driven by electric motors
• CPC Class Codes: F04B 53/143 Sealing provided on the piston
• CPC Class Codes: F04B 7/06 the pistons and cylinders being relatively reciprocated and rotated
• CPC Class Codes: F04B 9/02 the means being mechanical
• CPC Class Codes: F16J 15/3208 provided with tension elements, e.g. elastic rings
• CPC Class Codes: F16J 15/328 Manufacturing methods specially adapted for elastic sealings moulding B29C

Abstract

A piston head for a syringe pump comprises a barrier portion (11) for driving fluid through a syringe pump barrel (30), wherein a peripheral section (13,14) of the barrier portion (11) is shaped to seal against the syringe pump barrel (30); and a re-silent member (15) arranged to resist deformation of the shaped peripheral section (13,14) of the barrier portion (11).

Claims

1. A piston head, comprising:

i) an integrated structure that comprises a barrier portion, a retaining portion comprising an inside surface proximal to a central axis of the piston head and an outer surface distal to the central axis of the piston head, and a lip; and

ii) a separate resilient member,

wherein the resilient member is made of a material having a lower elastic modulus than the material of the integrated structure,

wherein the integrated structure is configured to directly connect to a piston,

wherein the lip projects from the barrier portion, so as to define an available space between the lip and the outer surface of the retaining portion,

wherein the retaining portion is configured for retaining the resilient member against the lip,

wherein the resilient member is positioned so as to fill the available space between the lip and the retaining portion and to resist inwards deformation of the lip, and

wherein an inner surface of the lip comprises an overhang and the resilient member projects beneath the overhang.

2. The piston head according to claim 1, wherein the lip is tapered such that a thickness of the lip decreases from a point where the lip joins the barrier portion to a tip.

3. The piston head according to claim 1, wherein the resilient member is made of a material that is different than a material of which the barrier portion is made.

4. The piston head according to claim 1, wherein the resilient member is subject to a lower creep than the lip.

5. The piston head according to claim 1, wherein the barrier portion is made of a plastics material having a dynamic coefficient of friction of less than or equal to 0.4 as measured relative to steel.

6. A piston head, comprising:

i) an integrated structure that comprises a barrier portion, a retaining portion comprising an inside surface proximal to a central axis of the piston head and an outer surface distal to the central axis of the piston head, and a lip; and

ii) a separate resilient member,

wherein the resilient member is made of a material having a lower elastic modulus than the material of the integrated structure,

wherein the integrated structure is configured to directly connect to a piston,

wherein the lip projects from the barrier portion, so as to define an available space between the lip and the outer surface of the retaining portion,

wherein the retaining portion is configured for retaining the resilient member against the lip,

wherein the resilient member is positioned so as to fill the available space between the lip and the retaining portion and to resist inwards deformation of the lip, and

wherein the resilient member is bonded to the lip and/or the retaining portion.

7. The piston head according to claim 6, wherein the resilient member is bonded to the lip and the retaining portion.

8. A method of forming a piston seal, the method comprising:

i) molding an integrated structure that comprises a barrier portion, a retaining portion comprising an inside surface proximal to a central axis of the piston head and an outer surface distal to the central axis of the piston head, and a lip, wherein the integrated structure is configured to directly connect to a piston;

ii) molding a separate resilient member that is made of a material having a lower elastic modulus than the material of the integrated structure; and

arranging the barrier portion and the retaining portion and the resilient member to form the piston seal, such that i) the lip projects from the barrier portion, so as to define an available space between the lip and the outer surface of the retaining portion, ii) the retaining portion is configured for retaining the resilient member against the lip, and iii) the resilient member is positioned so as to fill the available space between the lip and the retaining portion and to resist inwards deformation of the lip.

9. The method according to claim 8, wherein the steps of molding the integrated structure and molding the resilient member are performed as an over-molding or two-shot molding process.

10. A piston head, comprising:

i) an integrated structure that comprises a barrier portion, a retaining portion comprising an inside surface proximal to a central axis of the piston head and an outer surface distal to the central axis of the piston head, and a lip; and

ii) a separate resilient member,

wherein the resilient member is made of a material having a lower elastic modulus than the material of the integrated structure,

wherein the integrated structure is configured to directly connect to a piston,

wherein the lip projects from the barrier portion, so as to define an available space between the lip and the outer surface of the retaining portion,

wherein the retaining portion is configured for retaining the resilient member against the lip,

wherein the resilient member is positioned so as to fill the available space between the lip and the retaining portion and to resist inwards deformation of the lip, and

, wherein the resilient member extends further away from the barrier portion than the lip, in an axial direction, along the retaining portion.