Pressure measurement devices, methods, and systems

Patent metadata

Field	Value
Publication number	US-10345175-B2
Application number	US-201715800901-A
Country	US
Kind code	B2
Filing date	Nov 1, 2017
Priority date	May 31, 2011
Publication date	Jul 9, 2019
Grant date	Jul 9, 2019

Abstract

A pressure measurement pod for blood circuits can include a flexible, moveable, fluid-impermeable diaphragm and can be formed via either a one-shot or a two-shot molding process. A method of manufacturing a pressure measuring device can include providing first and second major mold parts having recesses defining major parts of a housing, and inserting pins in the first and second major mold parts, the pins being shaped to define a flow channel of a molded pressure measuring pod. One of the pins may have a major face that defines an internal surface of a diaphragm. The method may further include closing the first and second major mold parts with the pins therebetween and injection molding a pressure pod housing. Finally, the pressure pod is removed from the mold parts and the pins are withdrawn from the flow channel.

First claim

What is claimed is:

1. A method of manufacturing a molded pressure measuring pod that is configured to measure positive and negative pressure of a fluid that flows through the molded pressure measuring pod, the method comprising:
providing first and second major mold parts having recesses defining major parts of a housing of the pressure measuring pod;
inserting a first pin and a second pin, both having a positive draft, into the first and second major mold parts, the first pin and the second pin being shaped to define a first port and a second port and a flow channel that is configured to permit flow between the first port and the second port through the molded pressure measuring pod;
the first pin having a flat major face that defines an internal surface of a diaphragm, the diaphragm being configured to flex in response to pressure in the molded pressure measuring pod and to prevent flow of fluid through the diaphragm;
closing the first and second major mold parts with the first pin and the second pin therebetween;
injection molding the housing of the pressure measuring pod; and
separating the first and second major mold parts;
withdrawing the first pin and the second pin; and
removing the housing of the pressure measuring pod from the first and second major mold parts.

2. The method of claim 1 , wherein the withdrawing the first pin and the second pin opens ports in the housing that communicate through the housing.

3. The method of claim 1 , wherein one of the first pin and the second pin has a major dimension that is larger than, or equal in size to, the diaphragm.

4. The method of claim 2 , wherein one of the first pin and the second pin has a major dimension that is larger than, or equal in size to, the diaphragm.

5. The method of claim 1 , wherein one of the first pin and the second pin has a major dimension that is larger than, or equal in size to, a diameter of the diaphragm.

6. The method of claim 2 , wherein one of the first pin and the second pin has a major dimension that is larger than, or equal in size to, a diameter of the diaphragm.

7. The method of claim 1 , wherein the diaphragm has an engagement feature on an outside surface thereof.

8. The method of claim 2 , wherein the diaphragm has an engagement feature on an outside surface thereof.

9. The method of claim 3 , wherein the diaphragm has an engagement feature on an outside surface thereof.

10. The method of claim 4 , wherein the diaphragm has an engagement feature on an outside surface thereof.

11. The method of claim 5 , wherein the diaphragm has an engagement feature on an outside surface thereof.

12. The method of claim 6 , wherein the diaphragm has an engagement feature on an outside surface thereof.

13. The method of claim 7 , wherein the engagement feature is a projection.

14. The method of claim 12 , wherein the engagement feature is a projection.

15. The method of claim 1 , wherein
the inserting the first pin and the second pin includes positioning the first pin in direct contact with the second pin, such that a combined shape of the first pin and the second pin creates the flow channel through the molded pressure measuring pod.

16. The method of claim 14 , wherein
the inserting the first pin and the second pin includes positioning the first pin in direct contact with the second pin, such that a combined shape of the first pin and the second pin creates the flow channel through the molded pressure measuring pod.

17. The method of claim 1 , further comprising:
inserting a third pin that defines an outer surface of the diaphragm before the injection molding; and
withdrawing the third pin.

18. The method of claim 16 , further comprising:
inserting a third pin that defines an outer surface of the diaphragm before the injection molding; and
withdrawing the third pin.

19. The method of claim 1 , wherein the injection molding includes
injecting a thermoplastic material that hardens into a rigid structure.

20. The method of claim 18 , wherein the injection molding includes
injecting a thermoplastic material that hardens into a rigid structure.

Assignees

• Nxstage Medical Inc

Inventors

• Brugger James M
• Treu Dennis M
• Burbank Jeffrey H
• Newell Scott W
• Schnell William J
• Buckler Kenneth E

Classifications

• A61B5/021

  Measuring pressure in heart or blood vessels · CPC title

• G01L9/006 Primary

  of metallic strain gauges fixed to an element other than the pressure transmitting diaphragm · CPC title

• G01L9/0041 Primary

  Transmitting or indicating the displacement of flexible diaphragms · CPC title

• A61M2205/75

  with filters · CPC title

• G01L19/0046

  using isolation membranes (G01L13/026 and G01L19/0645 take precedence) · CPC title