Medical fluid pumping systems and related devices and methods

Patent metadata

Field	Value
Publication number	US-10143791-B2
Application number	US-201514870926-A
Country	US
Kind code	B2
Filing date	Sep 30, 2015
Priority date	Apr 21, 2011
Publication date	Dec 4, 2018
Grant date	Dec 4, 2018

Abstract

This disclosure relates to medical fluid pumping systems and related devices and methods. In some aspects, a medical fluid pumping system includes a medical fluid pumping machine including a piston head that can be linearly displaced and a medical fluid cassette that can be secured to the medical fluid pumping machine. The medical fluid cassette includes a fastening member attached to a region of a flexible membrane overlying a fluid pump chamber, and the piston head is configured to be mechanically connected to the fastening member of the cassette.

First claim

What is claimed is:

1. A medical fluid pumping machine comprising:
a piston head that can be linearly displaced, the piston head comprising a latch secured to a body portion of the piston head, the latch slidable relative to the body portion between a retracted position and an extended position in which an engagement surface of the latch is positioned radially outward of a perimeter of the body portion, the piston head being configured to be disposed within a recess defined by a fastening member of a medical fluid cassette, and the engagement surface of the latch being configured to engage an engagement surface of the fastening member of the medical fluid cassette when the piston head is disposed in the recess such that, when the piston head is disposed in the recess and is moved linearly away from a base of the cassette with the latch in the extended position, the engagement surface of the latch of the piston head is engaged with the engagement surface of the fastening member and pulls the fastening member and a flexible membrane to which the fastening member is attached away from the base to increase a volume of a fluid pump chamber defined in the cassette between the flexible membrane and the base.

2. The medical fluid pumping machine of claim 1 , wherein the latch of the piston head comprises a contact surface that extends radially beyond the perimeter of the body portion when the latch is in the extended position.

3. The medical fluid pumping machine of claim 2 , wherein the latch of the piston head is configured to move radially inwardly when the piston head is inserted into the recess of the fastening member.

4. The medical fluid pumping machine of claim 1 , wherein the latch of the piston head is radially movable relative to the body portion of the piston head.

5. The medical fluid pumping machine of claim 1 , wherein the engagement surface of the latch is configured to be positioned radially inward of the perimeter of the body portion when the latch is in the retracted position.

6. The medical fluid pumping machine of claim 1 , wherein the piston head is constructed to become mechanically connected to the fastening member when the piston head is moved toward the base of the cassette and to become disconnected from the fastening member when the piston head is moved away from the base of the cassette.

7. The medical fluid pumping machine of claim 1 , wherein the medical fluid pumping machine is a dialysis machine.

8. The medical fluid pumping machine of claim 1 , wherein the medical fluid pumping machine defines a cassette compartment configured to receive the cassette.

9. The medical fluid pumping machine of claim 8 , wherein the cassette compartment is defined by a door and a face of the medical fluid pumping machine.

10. The medical fluid pumping machine of claim 1 , wherein the body portion comprises front and rear members, and the latch is positioned in a space defined between the front and rear members.

11. The medical fluid pumping machine of claim 10 , wherein the piston head further comprises a latch lock having a first angled surface that sits adjacent an associated first angled surface of the latch such that radially inward movement of the latch causes axial movement of the latch lock in a first axial direction.

12. The medical fluid pumping machine of claim 11 , wherein the piston head further comprises a spring disposed between the latch lock and the front member to resist the axial movement of the latch lock in the first axial direction.

13. The medical fluid pumping machine of claim 12 , wherein the latch and the latch lock are configured such that when a force applied to the latch to move the latch radially inwardly and to move the latch lock axially is released, the spring expands and moves the latch lock in a second axial direction opposite the first axial direction and causes the latch to move radially outwardly.

14. The medical fluid pumping machine of claim 1 , further comprising a latch lock configured to move axially in a first axial direction when the latch moves radially inward.

15. A medical fluid pumping machine comprising:
a piston head that can be linearly displaced, the piston head comprising
a latch secured to a body portion of the piston head, the latch having an extended position in which an engagement surface of the latch is positioned radially outward of a perimeter of the body portion, the piston head being configured to be disposed within a recess defined by a fastening member of a medical fluid cassette, and the engagement surface of the latch being configured to engage an engagement surface of the fastening member of the medical fluid cassette when the piston head is disposed in the recess such that, when the piston head is disposed in the recess and is moved linearly away from a base of the cassette with the latch in the extended position, the engagement surface of the latch of the piston head is engaged with the engagement surface of the fastening member and pulls the fastening member and a flexible membrane to which the fastening member is attached away from the base to increase a volume of a fluid pump chamber defined in the cassette between the flexible membrane and the base, and
a latch lock having a first angled surface that sits adjacent an associated first angled surface of the latch such that radially inward movement of the latch causes axial movement of the latch lock in a first axial direction.

16. The medical fluid pumping machine of claim 15 , wherein the latch of the piston head comprises a contact surface that extends radially beyond the perimeter of the body portion when the latch is in the extended position.

17. The medical fluid pumping machine of claim 16 , wherein the latch of the piston head is configured to move radially inwardly when the piston head is inserted into the recess of the fastening member.

18. The medical fluid pumping machine of claim 15 , wherein the latch of the piston head is radially movable relative to the body portion of the piston head.

19. The medical fluid pumping machine of claim 15 , wherein the latch has a retracted position in which the engagement surface of the latch positioned radially inward of the perimeter of the body portion.

20. The medical fluid pumping machine of claim 15 , wherein the piston head is constructed to become mechanically connected to the fastening member when the piston head is moved toward the base of the cassette and to become disconnected from the fastening member when the piston head is moved away from the base of the cassette.

Assignees

• Fresenius Medical Care Holdings Inc

Inventors

• Farrell Sean
• Ly Tri
• Singh Gurpreet
• Plahey Kulwinder S
• Lindley Deloy
• Serrato Ignacio
• Ghatikar Venugopal Raghavendra
• Young Michael David

Classifications

• F04B43/02

  having plate-like flexible members, e.g. diaphragms (F04B43/14 takes precedence) · CPC title

• A61M1/14

  Dialysis systems; Artificial kidneys; Blood oxygenators (semi-permeable membranes characterised by the material, manufacturing processes therefor B01D71/00){; Reciprocating systems for treatment of body fluids, e.g. single needle systems for hemofiltration or pheresis} · CPC title

• A61M1/28 Primary

  Peritoneal dialysis {; Other peritoneal treatment, e.g. oxygenation} · CPC title

• A61M1/1081

  Human Necessities · mapped topic

• A61M5/1452

  pressurised by means of pistons · CPC title