Device for measuring pressure comprising a membrane moulded into a cassette

• US 20020107468A1
• Filed: 12/07/2001
• Published: 08/08/2002
• Est. Priority Date: 12/08/2000
• Status: Active Grant

• Current Assignee: Industries Gambro
• Original Assignee: Hospal International Marketing Management
• Inventors: Court, Thierry, Chevallet, Jacques, Mercier, Guy
• Granted Patent: US 6,684,710 B2
• Time in Patent Office: Days
• US Class Current: 604/5.01
• CPC Class Codes: A61M 1/3622 with a cassette forming partially or totally the blood circuit
• CPC Class Codes: A61M 1/36224 with sensing means or components thereof
• CPC Class Codes: A61M 1/36225 with blood pumping means or components thereof
• CPC Class Codes: A61M 1/36226 Constructional details of cassettes, e.g. specific details on material or shape
• CPC Class Codes: A61M 1/362261 at least one cassette surface or portion thereof being flexible, e.g. the cassette having a rigid base portion with preformed channels and being covered with a foil
• 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 2205/12 with interchangeable cassettes forming partially or totally the fluid circuit
• CPC Class Codes: G01L 19/0023 for flowthrough systems having a flexible pressure transmitting element

Abstract

The invention proposes a device for measuring the pressure of blood in a pipe (44) of an extracorporeal blood circuit (42) comprising a pressure measurement section (46) having a substantially rigid wall (64) including a hole (66) which is sealed by a closure element (68), the internal face (70) of which is in contact with the blood and the external face (72) of which is in contact with the ambient air, it being possible for the closure element (68) to be elastically deformed overall along a deformation axis (A-A) under the effect of the blood pressure, characterized in that the closure element (68) is made in a single piece with the associated rigid wall (64) of the pressure measurement section (46).

Claims

1. Device for measuring the pressure of blood in a pipe (44) of an extracorporeal blood circuit (42), comprising a pressure measurement section (46) having a substantially rigid wall (64) including a hole (66) which is sealed by a closure element (68), the internal face (70) of which is in contact with the blood and the external face (72) of which is in contact with the ambient air, it being possible for the closure element (68) to be elastically deformed or displaced overall along a deformation or displacement axis (A-A) which is substantially orthogonal to its general plane, under the effect of the blood pressure, the pressure measurement section (46) being designed to engage with a load sensor (56) so that a portion of the external face (72) of the closure element (68) is, in its rest state, in direct or indirect contact with a load sensor (56) which can measure the force applied axially on the internal face (70) of the closure element (68) by the blood pressure, in order to calculate therefrom the value of this pressure,

characterized in that the closure element (68) is made in a single piece with the associated rigid wall (64) of the pressure measurement section (46).

2. Device according to the preceding claim, characterized in that the closure element (68) includes a region (76) of lower resistance to elastic axial deformation, compared to the rigid wall (64).

3. Device according to the preceding claim, characterized in that the region (76) of lower resistance to elastic axial deformation circumscribes the portion of the external face of the closure element (68) which, in its rest state, is in direct or indirect contact with the load sensor (56).

4. Device according to the preceding claim, characterized in that the closure element (68) comprises a substantially rigid central pellet (74) which is delimited by a thinned peripheral annular region (76) of axial thickness less than the axial thickness of the rigid wall (64) in order to form an elastically deformable region.

5. Device according to the preceding claim, characterized in that the thinned region (76) is made by machining the rigid wall (64) associated with the closure element (68).

6. Device according to any one of the preceding claims, characterized in that the closure element (68) is made by moulding with the associated rigid wall (64).

7. Device according to any one of the preceding claims, characterized in that, in cross section on a plane which is substantially perpendicular to the general plane of the closure element (68), the profile of the thinned region (76) is substantially undulating.

8. Device according to any one of the preceding claims, characterized in that a load transmitter (78) is inserted axially between the external face (72) of the closure element (68) and the load sensor (56).

9. Device according to any one of the preceding claims, characterized in that the load sensor (56), or the load transmitter (78), applies an initial axial pretensioning force (F₀) to the closure element (68), in its rest state, for the purpose of making it possible, in particular, to measure a pressure less than the pressure of the ambient air or to measure a reduction in pressure with respect to a reference pressure.

10. Device according to claim 8, characterized in that the external face (72) of the closure element (68) comprises a gripping member, or a member that can be gripped (80), which engages with a complementary member (86) of the load transmitter (78), so as to secure the closure element (68) in axial displacement with the load transmitter (78), for the purpose of making it possible, in particular, to measure a pressure less than the pressure of the ambient air or to measure a reduction in pressure with respect to a reference pressure.

11. Device according to the preceding claim taken in combination with claim 6, characterized in that the gripping member, or the member which can be gripped (80), of the closure element (68) is made in a single piece with the pellet (74).

12. Device according to any one of the preceding claims, of the type in which a part of the circuit (42) is made up of a casing (48), or cassette, incorporating pipes (44) which are connected to the extracorporeal blood circuit (42), characterized in that the pressure measurement section (46) is an attached module which is mounted in an associated housing of the casing (48).

13. Device according to any one of the preceding claims taken in combination with claim 6, of the type in which a part of the circuit (42) is made from a casing (48), or cassette, incorporating pipes (44) which are connected to the extracorporeal blood circuit (42), characterized in that the pressure measurement section (46) is moulded into the casing (48).

14. Device according to any one of the preceding claims, characterized in that the closure element (68) is substantially disc-shaped.

15. Device according to any one of the preceding claims, characterized in that at least one portion of the rigid wall (64) bordering the hole (66) bears axially towards the outside against a support plate (50).