# US 4,393,713 A · Digital pressure-measuring device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 4,393,713 A - Document ID: US4393713A - Status: Granted - Kind: A - Application number: 06/241,743 - Filed: 1981-03-09 - Granted: 1983-07-19 - Earliest claimed: 1979-06-28 - Assignees: Mecilec - Inventors: Philippe Guillemot - Web page: https://patentgrep.com/patent/US4393713A ## CPC - G01L 11/00: Measuring steady or quasi-steady pressure of a fluid or a fluent solid material by means not provided for in group G01L7/00 or G01L9/00 - G01L 9/0041: {Transmitting or indicating the displacement of flexible diaphragms} - G01L 9/0076: {using photoelectric means} - G01L 9/008: {using piezoelectric devices (piezoelectric resonators G01L9/0022; surface acoustic waves G01L9/0025)} - G01L 9/0089: {Transmitting or indicating the displacement of pistons by electrical, electromechanical, magnetic or electromagnetic means (G01L9/0008 takes precedence)} - G01L 13/00: Devices or apparatus for measuring differences of two or more fluid pressure values - G01L 19/083: {electrical} - G01L: MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE (weighing G01G) ## Abstract The pressure-measuring device comprises a first chamber subjected to the pressure to be measured and a second chamber connected to the first through an opening fitted with a valve. The device further comprises a valve-control circuit and an element for detecting the instants at which the pressure difference between the two chambers attains a predetermined increment or decrement or a zero value. The detection element consists of a deformable pressure-tight wall placed between the two chambers and adapted to produce action on an optoelectronic, piezoelectric or electromechanical element which converts the deformation directly to logical signals. A bidirectional counter is provided for forward or backward counting of the increments and decrements obtained. ## Claims ### Claim 1 A digital pressure-measuring device comprising a first chamber subjected to the pressure to be measured, a second chamber connected to the first through an opening fitted with a valve, a pressure-tight partition-wall between the two chambers, said wall being deformable under the action of a pressure difference between the two chambers, an element for converting the deformation of the partition-wall directly to electrical logic signals indicating the appearance of a pressure difference equal to a predetermined increment +.DELTA.P and to a predetermined decrement -.DELTA.P and to zero, wherein said element comprises an optical emitter, two light guides in spaced relation, two photoreceivers and a screen secured to the deformable wall and capable of displacement between the emitter and the light guides in order to permit or prevent penetration of the light into either of the two guides, said device being further provided with means for initiating opening of the valve under the action of the logic signals which indicate the appearance of a pressure difference equal to +.DELTA.P and for initiating closure of said valve under the action of the signal which indicates that said difference is zero, bidirectional counting means for receiving said logic signals and accounting for the number of increments +.DELTA.P obtained and reduced by the number of decrements -.DELTA.P obtained. ### Claim 2 (depends on 1) A device according to claim 1, wherein the screen which is capable of displacement between the emitter and the light guides consists of a mask provided with an aperture which is placed in the rest position opposite to the interval between the two light guides. ### Claim 3 (depends on 1) A device according to claim 1, wherein the screen which is capable of displacement between the emitter and the light guides consists of the deformable pressure-tight partition-wall itself. ### Claim 4 (depends on 1) A device according to claim 1, wherein the valve aforesaid is constituted by a wall secured to a piezoelectric pastille. ### Claim 5 A digital pressure-measuring device comprising a first chamber subjected to the pressure to be measured, a second chamber connected to the first through an opening fitted with a valve, a pressure-tight partition-wall between the two chambers, said wall being deformable under the action of a pressure difference between the two chambers, an element for converting the deformation of the partition-wall directly to electrical logic signals indicating the appearance of a pressure difference equal to a predetermined increment +.DELTA.P and to a predetermined decrement -.DELTA.P and to zero, wherein said element comprises a piezoelectric element secured to the deformable leak-tight wall and capable of emitting electrical signals whose polarity indicates the direction of deformation of said wall, said device being further provided with means for initiating the opening of the valve under the action of the logic signals which indicate the appearance of a pressure difference equal to +.DELTA.P and for initiating closure of the valve under the action of the signal which indicates that this difference is zero, bidirectional counting means for receiving said logic signals and adapted to account for the number of increments +.DELTA.P obtained and reduced by the number of decrements -.DELTA.P obtained. ### Claim 6 (depends on 5) A device according to claim 5, wherein said device further comprises two circuits for shaping the electrical signals delivered by the piezoelectric element. ### Claim 7 A digital pressure-measuring device comprising a first chamber subjected to the pressure to be measured, a second chamber connected to the first through an opening fitted with a valve, a pressure-tight partition-wall between the two chambers, said wall being deformable under the action of a pressure difference between the two chambers, an element for converting the deformation of the partition-wall directly to electrical logic signals indicating the appearance of a pressure difference equal to a predetermined increment +.DELTA.P and to a predetermined decrement -.DELTA.P and to zero, wherein said element comprises four deformable metallic plates arranged symmetrically in pairs on each side of the deformable pressure-tight wall, each plate aforesaid being fitted with a contact and connected electrically to a voltage source through a resistor which is in turn connected to an output terminal, the deformable pressure-tight wall being also connected electrically to ground, said device being further provided with means for initiating the opening of the valve under the action of the logic signals which indicate the appearance of a pressure difference equal to .+-..DELTA.P and for initiating closure of the valve under the action of the signal which indicates that this difference is zero, bidirectional counting means for receiving said logic signals and adapted to account for the number of increments +.DELTA.P obtained and reduced by the number of decrements -.DELTA.P obtained.