Pressure sensor with a diaphragm and depth gauge comprising the same

• US 8,171,799 B2
• Filed: 06/18/2010
• Issued: 05/08/2012
• Est. Priority Date: 06/19/2009
• Status: Active Grant

• Current Assignee: The Swatch Group Research And Development Ltd (The Swatch Group AG)
• Original Assignee: The Swatch Group Research And Development Ltd (The Swatch Group AG)
• Inventors: Rebeaud, Nicolas
• Primary Examiner(s): ALLEN, ANDRE J
• Application Number:
  US12/818,920
• Publication Number:
  US 20100319459A1
• Time in Patent Office: 690 Days
• Field of Search: 73700-756
• US Class Current: 73/715
• CPC Class Codes: B63C 11/02 Divers' equipment
• CPC Class Codes: G01C 5/06 by using barometric means
• CPC Class Codes: G01L 7/082 construction or mounting of diaphragms of semiconductive diaphragms G01L9/0042
• CPC Class Codes: G04G 21/02 Detectors of external physical values, e.g. temperature

Abstract

The invention concerns a pressure sensor (5), particularly for a depth gauge (1), capable of having a high level of precision, owing to sufficient elastic deflection amplitude of the diaphragm (or membrane), while avoiding any risk of plastic deformation. The diaphragm (12) is formed by a flat metal disc. The peripheral region (13) thereof is neither welded nor inset, but it is pre-stressed against a stop strip (25) with a closed, preferably circular contour, and can pivot on the stop strip (25) when the diaphragm bends under the effect of fluid pressure in the pressure chamber (10). The pre-stressing may be achieved via a sealing gasket (21) located opposite the stop strip (25). Between said strip and a central aperture (15), a concave stop surface (20) limits the deflection of the diaphragm (12) and prevents any plastic deformation in the event of excessive pressure. Manufacture of the diaphragm is simple, with a high level of reproducibility, assembly is easy and the seal quality is high.

Claims

1. A pressure sensor including a body with a pressure chamber for receiving a fluid and a support element around said chamber, a cover secured to the body and provided with a stop strip that has a closed contour in correspondence with the support element of the body, a diaphragm, which is arranged between the body and the cover to seal off the pressure chamber, and which bends under the effect of a pressure difference between the two surfaces thereof, with a peripheral region of the diaphragm arranged between said support element and said stop strip, and transmission means, connected to a central region of the diaphragm for transmitting diaphragm deflection data to measuring or indicating means, wherein the diaphragm has a generally flat shape, in that the peripheral region of the diaphragm pivots on the stop strip when the diaphragm bends under the effect of an increase in fluid pressure in the pressure chamber, in that said support element is a sealing gasket mounted on the body and compressed between the body and the peripheral region of the diaphragm to press said peripheral region permanently against the stop strip, and in that the sealing gasket is located opposite the stop strip.

2. The pressure sensor according to claim 1, wherein the diaphragm and the stop strip are circular.

3. The pressure sensor according to claim 2, wherein the diaphragm is formed by a flat metal disc.

4. The pressure sensor according to claim 1, wherein, opposite the diaphragm, the cover has a stop surface located between a central aperture of the cover and the stop strip and shaped in such a way as to retain the diaphragm as soon as the latter reaches a deflection corresponding to a limit pressure.

5. The pressure sensor according to claim 4, wherein the stop surface has the approximate shape of a spherical cap.

6. The pressure sensor according to claim 1, wherein the support element is rigid and in that a sealing gasket is arranged and compressed between the peripheral region of the diaphragm and the cover next to the stop strip.

7. The depth gauge with a case containing a pressure sensor including a body with a pressure chamber for receiving a fluid and a support element around said chamber, a cover secured to the body and provided with a stop strip that has a closed contour in correspondence with the support element of the body, a diaphragm, which is arranged between the body and the cover to seal off the pressure chamber, and which is capable of bending under the effect of a pressure difference between the two surfaces thereof, with a peripheral region of the diaphragm arranged between said support element and said stop strip, and transmission means, connected to a central region of the diaphragm for transmitting diaphragm deflection data to measuring or indicating means, wherein the diaphragm has an approximately flat shape, in that the peripheral region of the diaphragm can pivot on the stop strip when the diaphragm bends under the effect of an increase in fluid pressure in the pressure chamber, in that said support element is a sealing gasket mounted on the body and compressed between the body and the peripheral region of the diaphragm to press said peripheral region permanently against the stop strip, and in that the sealing gasket is located approximately opposite the stop strip.

8. The depth gauge according to claim 7, wherein said pressure sensor body is formed by a back cover of the case.