Device for measuring pressure

• US 3,946,724 A
• Filed: 04/01/1974
• Issued: 03/30/1976
• Est. Priority Date: 04/09/1973
• Status: Expired due to Term

• Current Assignee: Thomson Medical-Telco
• Original Assignee: Thomson Medical-Telco
• Inventors: La Balme, Maurice
• Primary Examiner(s): Howell, Kyle L.
• Application Number:
  US05/456,475
• Time in Patent Office: 729 Days
• Field of Search: 128/2.05 D, 128/2.05 E, 128/2.05 T, 128/2.05 P, 128/2.06 E, 128/2.06 F, 128/DIG. 4, 73/398 AR, 73/398 R
• US Class Current: 73/706
• CPC Class Codes: A61B 5/0215 by means inserted into the body catheters A61M25/00
• CPC Class Codes: A61N 1/0565 Electrode heads
• CPC Class Codes: A61N 1/36564 controlled by blood pressure
• CPC Class Codes: G01L 9/0052 of piezoresistive elements circuits therefor G01L9/06
• CPC Class Codes: G01P 15/08 with conversion into electric or magnetic values
• CPC Class Codes: Y10S 128/902 Biological signal amplifier

Abstract

A device which will find particular use as a medical catheter for measuring the pressure and rate at which blood flows through the heart and the blood vessels.

An integrated circuit chip having at least one field effect transistor thereon, which is sensitive to deformation of the chip is mounted at one end inside the device. An elastic membrane typically made from natural rubber, is mounted in an opening in the side of the device. An unattached core or plunger is positioned between the membrane and the other end of the semiconductor chip, thus when pressure is applied to the membrane, it deforms the chip and provides an electric signal.

Claims

1. A device for measuring pressure of a medium comprising:

a chip of semiconducting material whereon an integrated circuit including at least one field effect transistor sensitive to deformation is formed;

means for defining a chamber housing said chip and impervious to said medium the pressure of which is to be measured relatively to that within said chamber, said chamber defining means including;

a casing, a fixed support integrally secured to said casing and fixedly carrying one end of said chip, a mandrel-shaped hollow guide member having a central opening and one end tightly secured to said casing so as to locate one end of said central opening adjacent the other, free end of said chip, and a resilient membrane stretched across and secured to the other end of said hollow guide member for imperviously covering the other end of said central opening; and

a rod-shaped core freely movably inserted inside said central opening having ends respectively in unattached contact with said membrane and said other, free end of said chip for transmitting the deformations of said membrane under pressure to said chip by axial displacements of said core.

2. Device as claimed in claim 1, wherein said resilient membrane is made of natural rubber and is stretched across said other end of said guide member by binding means.

3. Device as claimed in claim 1, wherein said fixed support includes an opening for connecting said chamber to a medium providing reference pressure.

4. Apparatus for measuring the pressure in a fluid, which comprises:

a housing having a chamber formed therein;

an integrated circuit transducer fastened at one end to said housing and extending upwardly into said chamber, said transducer including at least one field-effect transistor which is sensitive to deformation;

a mandrel-shaped guide member fastened to said housing, said guide member having a longitudinally extending bore therethrough and being positioned such that said bore is aligned with the other end of said transducer;

a resilient membrane stretched across and secured to said guide member to imperviously cover one end of said bore, said membrane being positioned proximate a window in the outer wall of said housing to thereby contact the fluid whose pressure is to be measured; and

a rod-shaped core slideably positioned inside said bore, the ends of said core respectively contacting said membrane and said other end of the transducer for transmitting deformations of said membrane under pressure to said transducer by the axial displacement of said core.

5. Apparatus according to claim 4 wherein said resilient membrane comprises natural rubber and is secured to said guide member by binding means.

6. Apparatus according to claim 4 wherein said housing further includes an opening into said chamber to connect said chamber to a source of a reference pressure.