Fiberoptic pressure transducer

• US 5,425,371 A
• Filed: 10/28/1993
• Issued: 06/20/1995
• Est. Priority Date: 10/05/1992
• Status: Expired due to Fees

• Current Assignee: Metatech Corporation
• Original Assignee: Metatech Corporation
• Inventors: Mischenko, Peter S.
• Primary Examiner(s): Sykes, Angela D.
• Application Number:
  US08/144,897
• Time in Patent Office: 600 Days
• Field of Search: 128/633-634, 128/664-667, 128/672-675, 128/748, 73/705, 73/708, 73/715
• US Class Current: 73/705
• CPC Class Codes: A61B 5/02154 by optical transmission

Abstract

A fiberoptic fluid pressure transducer system involving a thin flat diaphragm, fiberoptic elements, a tubular member having an opening of fixed dimensions on the side thereof, an L-shaped cantilevered beam and a remotely located electronic control unit. The cantilevered beam has one leg horizontally attached to a recessed ledge surrounding the opening such that a vertical leg extending from the horizontal leg, including a light reflector, extends into the opening. A diaphragm covers the opening and makes physical contact with the horizontal leg of the L-shaped beam. Pressure applied to the diaphragm flexes the horizontal leg of the beam which, in turn, causes a spatial displacement of the vertical leg with respect to the fiberoptic elements. The resulting change in reception of the reflected light is proportional to the pressure applied to the diaphragm or membrane. The sensitivity of the transducer can be altered and the system can have two or more levels of sensitivity over a range of pressure measurements.

Claims

1. A fiberoptic pressure transducer comprising:

a housing with a side wall;

an opening in the wall extending into a cavity formed in the housing;

a flexible L-shaped leaf structure having two legs, one leg being attached at one end to the wall and extending horizontally in a cantilevered fashion for a length over said cavity with the other leg extending vertically into the cavity;

a flexible diaphragm covering the opening and contacting the horizontal leg of the cantilevered L-shaped leaf structure;

a reflective surface on one side of the vertical leg of the L-shaped leaf structure that extends into the cavity;

at least one fiberoptic rod mounted in the housing in spaced relationship with the reflective surface for transmitting light to and receiving light from the reflective surface such that when pressure is applied to the diaphragm, the vertical leg of the leaf structure is flexed inwardly into said cavity in response to the applied pressure and the spatial position of the reflective surface changes with respect to the at least one fiberoptic rod so as to change the amount of reflected light received by the at least one fiberoptic rod in proportion to the applied pressure; and

means for adjusting the length of the horizontal leg of the L-shaped leaf structure that extends over the cavity to vary sensitivity of the pressure transducer.

2. A fiberoptic pressure transducer comprising:

a housing with a side wall;

an opening in the wall extending into a cavity formed in the housing;

a flexible L-shaped leaf structure having two legs, one leg being attached at one end to the wall and extending horizontally in a cantilevered fashion for a length over said cavity with the other leg extending vertically into the cavity;

a flexible diaphragm covering the opening and contacting the horizontal leg of the cantilevered L-shaped leaf structure;

a reflective surface on one side of the vertical leg of the L-shaped leaf that extends into the opening; and

at least one fiberoptic rod mounted in the housing in spaced relationship with the reflective surface for transmitting light to and receiving light from the reflective surface such that when pressure is applied to the diaphragm, the vertical leg of the leaf structure is flexed inwardly into said cavity in response to the applied pressure and changes the spatial position of the reflective surface changes with respect to the at least one fiberoptic rod so as to change the amount of reflected light received by the at least one fiberoptic rod in proportion to the applied pressure;

a recessed ledge around the opening in the housing wall for receiving the horizontal leg of the L-shaped leaf structure and the flexible diaphragm covering the opening; and

a sensitivity adjusting means comprising;

a slot in the horizontal leg of the L-shaped leaf structure; and

an orifice in the recessed ledge around the opening such that an attachment device removably inserted in the orifice through the slot allows the length of the horizontal leg extending over the cavity to be adjusted thus varying the flexibility and the pressure sensitivity of the transducer.

3. A pressure transducer as in claim 2 further including mounting means for attaching the L-shaped leaf to the recessed ledge so as to establish a first pressure sensitivity over a first range of flexure of the horizontal leg and a second pressure sensitivity over a second range of flexure of the horizontal leg.

4. A fiberoptic pressure transducer comprising:

a housing with a side wall;

an opening in the wall extending into a cavity formed in the housing;

a flexible L-shaped leaf structure having a first and a second leg, said first leg being attached at a first end to the wall and extending horizontally in a cantilevered fashion for a length over said cavity and being attached at a second end to the second leg, said second leg extending vertically into the cavity;

a flexible diaphragm covering the opening and contacting the horizontal leg of the cantilevered L-shaped leaf structure;

a reflective surface on one side of the vertical leg of the L-shaped leaf structure that extends into the cavity;

at least one fiberoptic rod mounted in the housing in spaced relationship with the reflective surface for transmitting light to and receiving light from the reflective surface such that when pressure is applied to the diaphragm the vertical leg of the leaf structure is flexed inwardly into said cavity in response to the applied pressure and the spacial position of the reflective surface changes with respect to the at least one fiberoptic rod so as to change the amount of reflected light received by the at least one fiberoptic rod in proportion to the applied pressure;

.

a recessed ledge having a bearing surface extending in a horizontal plane and including an edge around the opening in the housing wall for receiving the horizontal leg of the L-shaped leaf structure and the flexible diaphragm covering the opening;

mounting means for attaching the L-shaped leaf structure to the recessed ledge so as to establish a first pressure sensitivity over a first range of flexure of the horizontal leg and a second pressure sensitivity over a second range of flexure of the horizontal leg;

the mounting means comprising;

an angled portion formed intermediate said first end and said second end end of the horizontal leg; and

connecting means for attaching the first end of the horizontal leg to the recessed ledge such that the angled portion of the horizontal leg is angled upwardly relative to the horizontal plane of said bearing surface and does not touch the edge of the recessed ledge whereby a first pressure deflects the angled portion of the horizontal leg until it contacts the edge of the recessed ledge and a second greater pressure deflects the second end of the horizontal leg beyond the ledge below the plane of the bearing surface of the ledge.