Pressure measurement devices, methods, and systems

• US 10,345,175 B2
• Filed: 11/01/2017
• Issued: 07/09/2019
• Est. Priority Date: 05/31/2011
• Status: Active Grant

• Current Assignee: Nxstage Medical Incorporated (Fresenius Medical Care AG)
• Original Assignee: Nxstage Medical Incorporated (Fresenius Medical Care AG)
• Inventors: Brugger, James M., Treu, Dennis M., Burbank, Jeffrey H., Newell, Scott W., Schnell, William J., Buckler, Kenneth E.
• Primary Examiner(s): Del Sole, Joseph S
• Assistant Examiner(s): Luk, Emmanuel S
• Application Number:
  US15/800,901
• Publication Number:
  US 20180128698A1
• Time in Patent Office: 615 Days
• CPC Class Codes: A61M 1/362227 the interface providing means for actuating on functional elements of the cassette, e.g. plungers
• CPC Class Codes: A61M 1/36224 with sensing means or components thereof
• CPC Class Codes: A61M 1/3639 Blood pressure control, pressure transducers specially adapted therefor
• CPC Class Codes: A61M 1/3641 Pressure isolators
• CPC Class Codes: A61M 1/3653 Interfaces between patient blood circulation and extra-corporal blood circuit
• CPC Class Codes: A61M 1/3659 Cannulae pertaining to extracorporeal circulation
• CPC Class Codes: A61M 2205/3331 Pressure; Flow
• CPC Class Codes: A61M 2205/75 with filters
• CPC Class Codes: A61M 2207/00 Methods of manufacture, assembly or production
• CPC Class Codes: G01L 19/0023 for flowthrough systems having a flexible pressure transmitting element
• CPC Class Codes: G01L 19/003 using a detachable interface or adapter between the process medium and the pressure gauge
• CPC Class Codes: G01L 19/0046 using isolation membranes G01L13/026 and G01L19/0645 take precedence
• CPC Class Codes: G01L 9/0041 Transmitting or indicating the displacement of flexible diaphragms
• CPC Class Codes: G01L 9/006 of metallic strain gauges fixed to an element other than the pressure transmitting diaphragm

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.

Claims

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.