Precision pressure gauge

Claim 2

A precision pressure gauge comprising: a pressure capsule providing a pressure chamber; a fused quartz, helical, bourdon tube mounted in the pressure chamber, having one end fixed to the pressure capsule, and having a free end for transducing a pressure differential across the walls of the bourdon tube into rotary motion; a reflective means secured to the bourdon tube for rotation therewith; an electromagnetic radiation source fixed with respect to the pressure capsule for directing a well-defined electromagnetic radiation beam onto the reflective means; an electromagnetic radiation means fixed with respect to the pressure capsule for sensing the electromagnetic radiation beam directed by the electromagnetic radiation source onto the reflective means and reflected from the reflective means and for generating an electrical signal proportional to the quantity of the electromagnetic radiation incident thereon; and two electromagnets directly connected to the bourdon tube on opposite sides thereof for rotation therewith, the two electromagnets producing equal but opposite forces providing torque to the bourdon tube for rotating about its axis of rotation.

Claim 3

A precision pressure gauge comprising: a pressure capsule providing a pressure chamber; a fused quartz, helical, bourdon tube mounted in the pressure chamber, having one end fixed to the pressure capsule, and having a free end for transducing a pressure differential across the walls of the bourdon tube into rotary motion; a reflective means secured to the bourdon tube for rotation therewith; an electromagnetic radiation source fixed with respect to the pressure capsule for directing a well-defined electromagnetic radiation beam onto the reflective means; an electromagnetic radiation detection means fixed with respect to the pressure capsule for sensing the electromagnetic radiation beam directed by the electromagnetic radiation source onto the reflective means and reflected from the reflective means and for generating an electrical signal proportional to the quantity of the electromagnetic radiation incident thereon; and amplifier means coupled to the output of the electromagnetic radiation detection means for amplifying the electrical signal; at least one electromagnet assembly associated with the bourdon tube, a portion of such electromagnet assembly being connected directly to the bourdon tube for rotation therewith; electrical conductor means connected between the amplifier means and the electromagnet assembly for supplying the amplified electrical signal to the electromagnet assembly whereby the electromagnet assembly applies torque to the bourdon tube in a magnitude proportional to the eLectrical signal and sufficient to prevent the bourdon tube from rotating appreciably from its initial null position to a new null position representative of the pressure differential being experienced by the bourdon tube; a precision resistance; a linearizing circuit; electrical conductor means connected between the electromagnet assembly and the precision resistance and between the precision resistance and the linearizing circuitry for conducting the amplified electrical signal, after it has been supplied to the electromagnet assembly, through the precision resistance and to the linearizing circuitry; a readout apparatus; and electrical conductor means connected between the electromagnet assembly and the readout apparatus and between the linearizing circuit and the readout apparatus.

Claim 4

A precision pressure gauge comprising: a pressure capsule providing a pressure chamber; a fused quartz, helical, bourdon tube mounted in the pressure chamber, having one end fixed to the pressure capsule, and having a free end for transducing a pressure differential across the walls of the bourdon tube into rotary motion; a reflective means secured to the bourdon tube for rotation therewith; an electromagnetic radiation source fixed with respect to the pressure capsule for directing a well-defined electromagnetic radiation beam onto the reflective means; an electromagnetic radiation detection means fixed with respect to the pressure capsule for sensing the electromagnetic radiation beam directed by the electromagnetic radiation source onto the reflective means and reflected from the reflective means and for generating an electrical signal proportional to the quantity of the electromagnetic radiation incident thereon; and amplifier means coupled to the output of the electromagnetic radiation detection means for amplifying the electrical signal; at least one electromagnet assembly associated with the bourdon tube, a portion of such electromagnet assembly being connected directly to the bourdon tube for rotation therewith; electrical conductor means connected between the amplifier means and the electromagnet assembly for supplying the amplified electrical signal to the electromagnet assembly whereby the electromagnet assembly applies torque to the bourdon tube in a magnitude proportional to the eLectrical signal and sufficient to prevent the bourdon tube from rotating appreciably from its initial null position to a new null position representative of the pressure differential being experienced by the bourdon tube; a precision resistance; a linearizing circuit; electrical conductor means connected between the electromagnet assembly and the precision resistance and between the precision resistance and the linearizing circuitry for conducting the amplified electrical signal, after it has been supplied to the electromagnet assembly, through the precision resistance and to the linearizing circuitry; a readout apparatus; and electrical conductor means connected between the electromagnet assembly and the readout apparatus and between the linearizing circuit and the readout apparatus.

Claim 5

A precision pressure gauge according to claim 2 wherein the linearizing means comprises discrete electronics designed to solve the following equation: y (ax2+ bx)k wherein y is an electrical signal proportional to the non-linearity of the amplified electrical signal produced by the electromagnetic radiation detection means as a result of the pressure differential across the walls of the bourdon tube, x is the magnitude of the electrical signal supplied to the linearizing means, a and b are constants, and k is an empirically determined constant.

Claim 6

A precision pressure gauge comprising: a pressure capsule providing a pressure chamber; a fused quartz, helical, bourdon tube mounted in the pressure chamber, having one end fixed to the pressure capsule and having a free end for transducing a pressure differential across the walls of the bourdon tube into rotary motion; means through the pressure capsule for supplying pressure to the inside of the walls of the bourdon tube; means through the pressure capsule for supplying pressure to the outside of the walls of the bourdon tube; a reflective means secured to the bourdon tube for rotation therewith; means in the pressure capsule for allowing the transfer of electromagnetic radiation; an electromagnetic radiation source fixed with respect to the pressure capsule for directing a well-defined beam of electromagnetic radiation through the electromagnetic radiation transferring means in the pressure capsule and onto the reflective means; a pair of solar cells fixed with respect to the pressure capsule for sensing the beam of electromagnetic radiation generated by the electromagnetic radiation source onto the reflective means and reflected from the reflective means back through the electromagnetic radiation transferring means in the pressure capsule, each of the solar cells generating an electrical signal of selected polarity proportional to the quantity of reflected electromagnetic radiation incident thereon; an amplifier coupled to the output of the two solar cells for amplifying the cumulative electrical signal generated by the two solar cells; first and second electromagnet assemblies connected to the bourdon tube on opposite sides thereof for rotation therewith; electrical conductor means electrically connecting the amplifier to the two electromagnet assemblies, whereby the amplified electrical signal is supplied to the electromagnet assemblies, the two electromagnet assemblies thereby producing equal but opposite forces providing torque to the bourdon tube for rotating it about its axis of rotation in the direction opposite to that produced by a pressure differential across the walls of the bourdon tube, the magnitude of the amplified electrical signal being such that the torque supplied to the bourdon tube by the two electromagnet assemblies is sufficient under ordinary circumstances to prevent appreciable rotary movement of the bourdon tube and, if the bourdon tube should experience unusual rotation, to return the bourdon tube to its proper null position for the pressure differential being experienced; a linearIzing means for adjusting the magnitude of the electrical signal supplied thereto to compensate for any non-linearity therein; electrical conductor means connecting the two electromagnet assemblies to the linearizing means whereby the amplified electrical signal is supplied to the linearizing means after such signal has been supplied across the two electromagnet assemblies; a readout means for displaying the pressure differential being measured across the wall of the bourdon tube; and electrical conductor means connecting the linearizing means to the readout means.

Claim 7

A precision pressure gauge comprising: a pressure capsule providing a pressure chamber; a fused quartz, helical, bourdon tube mounted in the pressure chamber, having one end fixed to the pressure capsule and having a free end for transducing a pressure differential across the walls of the bourdon tube into rotary motion; means through the pressure capsule for supplying pressure to the inside of the walls of the bourdon tube; means through the pressure capsule for supplying pressure to the outside of the walls of the bourdon tube; a reflective means secured to the bourdon tube for rotation therewith; means in the pressure capsule for allowing the transfer of electromagnetic radiation; an electromagnetic radiation source fixed with respect to the pressure capsule for directing a well-defined beam of electromagnetic radiation through the electromagnetic radiation transferring means in the pressure capsule and onto the reflective means; a pair of solar cells fixed with respect to the pressure capsule for sensing the beam of electromagnetic radiation generated by the electromagnetic radiation source onto the reflective means and reflected from the reflective means back through the electromagnetic radiation transferring means in the pressure capsule, each of the solar cells generating an electrical signal of selected polarity proportional to the quantity of reflected electromagnetic radiation incident thereon; an amplifier coupled to the output of the two solar cells for amplifying the cumulative electrical signal generated by the two solar cells; first and second electromagnet assemblies connected to the bourdon tube on opposite sides thereof for rotation therewith; electrical conductor means electrically connecting the amplifier to the two electromagnet assemblies, whereby the amplified electrical signal is supplied to the electromagnet assemblies, the two electromagnet assemblies thereby producing equal but opposite forces providing torque to the bourdon tube for rotating it about its axis of rotation in the direction opposite to that produced by a pressure differential across the walls of the bourdon tube, the magnitude of the amplified electrical signal being such that the torque supplied to the bourdon tube by the two electromagnet assemblies is sufficient under ordinary circumstances to prevent appreciable rotary movement of the bourdon tube and, if the bourdon tube should experience unusual rotation, to return the bourdon tube to its proper null position for the pressure differential being experienced; a linearIzing means for adjusting the magnitude of the electrical signal supplied thereto to compensate for any non-linearity therein; electrical conductor means connecting the two electromagnet assemblies to the linearizing means whereby the amplified electrical signal is supplied to the linearizing means after such signal has been supplied across the two electromagnet assemblies; a readout means for displaying the pressure differential being measured across the wall of the bourdon tube; and electrical conductor means connecting the linearizing means to the readout means.

Claim 8

A precision pressure gauge according to claim 4 wherein the linearizing means comprises discrete electronics designed to solve the following equation: y (ax2 + bx)k wherein y is an electrical signal proportional to the non-linearity of the amplified electrical signal produced by the pair of solar cells as a result of the pressure differential across the walls of the bourdon tube, x is the magnitude of the electrical signal supplied to the linearizing means, a and b are constants, and k is an empirically determined constant.

Claim 9

A precision pressure gauge according to claim 4 wherein the readout means comprises: a precision resistor; and a readout apparatus which displays data responsive to the voltage drop across the precision resistance and the output of the linearizing means.

Claim 10

A precision pressure gauge according to claim 6 wherein the readout means is a digital readout means having a high input and a low input and including: electrical conductor means connecting the electromagnetic assemblies with the precision resistance and connecting the electromagnet assemblies with the high input of the digital readout means; and electrical conductor means connecting the linearizing means with the low input of the digital readout means; wherein the digital readout means algebraically sums the two signals supplied to it, thereby providing a linear and direct display of the pressure being measured.

Claim 11

A precision pressure gauge comprising: a pressure capsule providing a pressure chamber; a bourdon tube mounted in the pressure chamber, one end of the bourdon tube being movable in response to a pressure differential experienced across the walls of the bourdon tube; means associated with the bourdon tube for sensing such movement of the end of the bourdon tube and for generating an electrical signal representative thereof; means for receiving the electrical signal generated by the sensing means and amplifying such signal by a selected magnitude; means associated with the bourdon tube for supplying to the bourdon tube a precisely controlled force responsive to an electrical signal supplied to such force means; means for supplying the amplified electrical signal to the force means associated with the bourdon tube; the force means associated with the bourdon tube applying a force to the bourdon tube responsive to the amplified electrical signal such that the end of the bourdon tube is allowed to move a very small almost infinitesimal amount from its initial null position to a new null position; a linearizing means for adjusting the magnitude of the amplified electrical signal to compensate for any nonlinearity in such electrical signal; and a readout means for receiving the linearized electrical signal and for displaying the pressure differential being experienced across the wall of the bourdon tube.

Claim 12

A precision pressure gauge comprising: a pressure capsule providing a pressure chamber; a bourdon tube mounted in the pressure chamber, one end of the bourdon tube being movable in response to a pressure differential experienced across the walls of the bourdon tube; means associated with the bourdon tube for sensing such movement of the end of the bourdon tube and for generating an electrical signal representative thereof; means for receiving the electrical signal generated by the sensing means and amplifying such signal by a selected magnitude; means associated with the bourdon tube for supplying to the bourdon tube a precisely controlled force responsive to an electrical signal supplied to such force means; means for supplying the amplified electrical signal to the force means associated with the bourdon tube; the force means associated with the bourdon tube applying a force to the bourdon tube responsive to the amplified electrical signal such that the end of the bourdon tube is allowed to move a very small almost infinitesimal amount from its initial null position to a new null position; a linearizing means for adjusting the magnitude of the amplified electrical signal to compensate for any nonlinearity in such electrical signal; and a readout means for receiving the linearized electrical signal and for displaying the pressure differential being experienced across the wall of the bourdon tube.

Claim 13

A precision pressure gauge comprising: a pressure capsule providing a pressure chamber; a bourdon tube mounted in the pressure chamber, one end of the bourdon tube being movable in response to a pressure differential experienced across the walls of the bourdon tube; a reflective means secured to the bourdon tube for rotation therewith; an electromagnetic radiation source fixed with respect to the pressure capsule for directing a well-defiNed electromagnetic radiation beam into the reflective means; two solar cells mounted adjacent to each other on either side of the initial null position of the electromagnetic radiation beam reflected from the reflective means, each solar cell generating an electrical signal of selected polarity proportional to the quantity of the electromagnetic radiation incident thereon; means associated with the bourdon tube for supplying to the bourdon tube a precisely controlled force responsive to an electrical signal supply to such force means; means for supplying the electrical signal generated by the one of the solar cells on which the reflected electromagnetic radiation beam is directed, to the force means associated with the bourdon tube; and the force means associated with the bourdon tube applying a force to the bourdon tube responsive to the electrical signal such that the end of the bourdon tube is allowed to move only a very small almost infinitesimal amount from its initial null position to a new null position, such movement by the bourdon tube being limited within a single displacement increment whereby the electromagnetic radiation beam does not extend beyond the solar cell mounted on either side of the initial null position.

Claim 14

A precision pressure gauge comprising: a pressure capsule providing a pressure chamber; a bourdon tube mounted in the pressure chamber, one end of the bourdon tube being movable in response to a pressure differential experienced across the walls of the bourdon tube; a reflective means secured to the bourdon tube for rotation therewith; an electromagnetic radiation source fixed with respect to the pressure capsule for directing a well-defiNed electromagnetic radiation beam into the reflective means; two solar cells mounted adjacent to each other on either side of the initial null position of the electromagnetic radiation beam reflected from the reflective means, each solar cell generating an electrical signal of selected polarity proportional to the quantity of the electromagnetic radiation incident thereon; means associated with the bourdon tube for supplying to the bourdon tube a precisely controlled force responsive to an electrical signal supply to such force means; means for supplying the electrical signal generated by the one of the solar cells on which the reflected electromagnetic radiation beam is directed, to the force means associated with the bourdon tube; and the force means associated with the bourdon tube applying a force to the bourdon tube responsive to the electrical signal such that the end of the bourdon tube is allowed to move only a very small almost infinitesimal amount from its initial null position to a new null position, such movement by the bourdon tube being limited within a single displacement increment whereby the electromagnetic radiation beam does not extend beyond the solar cell mounted on either side of the initial null position.