US3908460A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Pressure transducer
Assignee: AMBITEX CORP AND CENDEV CORP A
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Filing: 1974-02-28
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Granted: 1975-09-30
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Expires: 1994-02-28
Abstract
Abstract Minute movement of a bellows from a quiescent position as a result of pressure in the bellows is detected by a photodetector and light source to generate a signal constituting a function of the position of the bellows. This signal is amplified and fed back to a coil with a cooperative magnetic core to generate electromagnetically a force opposing the movement of the bellows. The greater the movement, the greater is the opposing force so that the bellows reaches an equilibrium position very close to its quiescent position. By then measuring the value of the signal, an extremely accurate measurement of the opposing force and thus the balancing pressure in the bellows is attained.
Inventors
- 👤 Abraham Lichowsky
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 15:15
CPC Classifications
G; G01; G01L; G01L11/00; G01L11/004; G01L11/008; G01L9/00; G01L9/0033; G01L9/0039
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
254 words
A pressure transducer comprising, in combination: a. movable means responsive to a pressurE to be measured, said movable means being capable of assuming different positions for different pressures; b. analog signal generating means responsive to said movable means for generating an analog signal constituting a function of the position of said movable means; c. pulse generating means including a voltage controlled oscillator connected to said analog signal generating means to receive said analog signal and provide an output series of pulses of frequency constituting a function of said analog signal; d. counter means including a counter connected to receive said series of pulses; time interval generating means connected to said counter to actuate the counter for a given time interval; and a digital display connected to the counter to provide a digital reading corresponding to the number of counts counted by said counter during said given time interval to thereby provide an indication of the frequency thereof; e. electro-magnetic means connected to said movable means; and f. feedback means including an integrator receiving said series of pulses and providing a feedback signal to said electromagnetic means derived from said analog signal to generate an electro-magnetic force opposing the direction of movement of said movable means whereby an equilibrium position is reached by said movable means, the frequency of said series of pulses constituting a function of the pressure opposing said electromagnetic force when equilibrium is reached so that a pressure reading may be provided by properly calibrating the indicated frequency in terms of pressure.
Claim 2
Dependent Claim
254 words
A pressure transducer comprising, in combination: a. movable means responsive to a pressurE to be measured, said movable means being capable of assuming different positions for different pressures; b. analog signal generating means responsive to said movable means for generating an analog signal constituting a function of the position of said movable means; c. pulse generating means including a voltage controlled oscillator connected to said analog signal generating means to receive said analog signal and provide an output series of pulses of frequency constituting a function of said analog signal; d. counter means including a counter connected to receive said series of pulses; time interval generating means connected to said counter to actuate the counter for a given time interval; and a digital display connected to the counter to provide a digital reading corresponding to the number of counts counted by said counter during said given time interval to thereby provide an indication of the frequency thereof; e. electro-magnetic means connected to said movable means; and f. feedback means including an integrator receiving said series of pulses and providing a feedback signal to said electromagnetic means derived from said analog signal to generate an electro-magnetic force opposing the direction of movement of said movable means whereby an equilibrium position is reached by said movable means, the frequency of said series of pulses constituting a function of the pressure opposing said electromagnetic force when equilibrium is reached so that a pressure reading may be provided by properly calibrating the indicated frequency in terms of pressure.
Claim 3
Dependent Claim
71 words
A pressure transducer according to claim 1, in which said analog signal generating means comprises a light source and photo-detector cell in alignment to receive light from said source; shutter means secured to said movable means for movement therewith such that the shutter eclipses the light to a degree determined by its position; and amplifier means connected to said photo-detector cell to amplify the signal therefrom to provide said analog signal.
Claim 4
Dependent Claim
40 words
A pressure transducer according to claim 1, in which said movable means comprises a pressure bellows and said electro-magnetic means includes an electrical coil surrounding a core of magnetic material, said electrical coil being connected to receive said feedback signal.
Claim 5
Dependent Claim
21 words
A pressure transducer according to claim 3, in which said core is stationary and said coil is affixed to said bellows.
Claim 6
Dependent Claim
25 words
A pressure transducer according to claim 3, in which said electrical coil is stationary and said core is coupled to said bellows for movement thereby.
Claim 7
Dependent Claim
41 words
A pressure transducer according to claim 5, in which there is provided a lever member coupling the core to the bellows so that movement of the core in response to movement of the bellows is mechanically amplified by said lever member.
References Cited (Backward Citations)
US3455166A
Cited
US3739645A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-09-29 | 1979-03-31 | 1979-09-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-29 | 1983-03-31 | 1983-09-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-29 | 1987-03-31 | 1987-09-30 | $7700.00 | Window Closed / Lapsed |