Patent US1735051A successfully refreshed from Google Patents.
US3847507A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Liquid supply system by pump
Assignee: Tosoh Corp
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Filing: 1973-05-17
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Granted: 1974-11-12
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Expires: 1993-05-17
Abstract
Abstract A system for supplying a liquid at constant pressure for use in a liquid chromatograph characterized by a pump having a cylinder and a piston reciprocably disposed therein for drawing liquid into and discharging liquid from the cylinder, wherein a tachogenerator is connected to an electric motor which is controlled by an automatic control circuit for detecting the hydraulic pressure in the cylinder having a differential amplifier therein, and in which a signal from the tacho-generator is fed back to the differential amplifier for controlling the movement of the piston being effected by the motor through a gearing arrangement, and a screw drive means connecting the motor and the piston.
Inventors
- 👤 K Sakiyama
- 👤 T Hashimoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 04:58
CPC Classifications
G; G01; G01N; G01N30/00; G01N30/02; G01N30/26; G01N30/28; G01N30/32; B; B01; B01L; B01L3/00; B01L3/02; B01L3/0203; B01L3/0206; F; F04; F04B; F04B49/00; F04B49/06; F04B49/08; G01N2030/326
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
99 words
A system for supplying a liquid at constant pressure comprising: a cylinder having an inlet and an outlet, a piston reciprocably disposed within said cylinder for drawing liquid into and discharging liquid from said cylinder, an electric motor, means connecting said motor to said piston to enable said motor to reciprocate said piston, means within said cylinder for detecting a pressure change in said cylinder, means responsive to said pressure change detecting means for actuating said motor, means for detecting the speed of said motor, means responsive to said speed detection means for reducing the speed of said motor.
Claim 2
Independent Claim
99 words
A system for supplying a liquid at constant pressure comprising: a cylinder having an inlet and an outlet, a piston reciprocably disposed within said cylinder for drawing liquid into and discharging liquid from said cylinder, an electric motor, means connecting said motor to said piston to enable said motor to reciprocate said piston, means within said cylinder for detecting a pressure change in said cylinder, means responsive to said pressure change detecting means for actuating said motor, means for detecting the speed of said motor, means responsive to said speed detection means for reducing the speed of said motor.
Claim 3
Dependent Claim
21 words
A system in accordance with claim 1, wherein said means for detecting the speed of said motor comprises a tacho generator.
Claim 4
Dependent Claim
23 words
A system in accordance with claim 1, wherein said means for detecting a pressure change comprises a strain gauge disposed within said cylinder.
Claim 5
Dependent Claim
20 words
A system in accordance with claim 1, wherein said means for actuating said motor comprises a rotary speed control circuit.
Claim 6
Dependent Claim
20 words
A system in accordance with claim 1, wherein said means responsive to said speed detection means comprises a sychronous rectifier.
Claim 7
Dependent Claim
20 words
A system in accordance with claim 1, wherein said means responsive to said speed detection means comprises a differential amplifier.
Claim 8
Dependent Claim
31 words
A system in accordance with claim 1, wherein said means for detecting a pressure change in said cylinder comprises a reference voltage generator connected to the input of a differential amplifier.
Claim 9
Independent Claim
185 words
A system for supplying a liquid at constant pressure comprising: a cylinder having an inlet and an outlet, a piston reciprocably disposed within said cylinder for drawing liquid into and discharging liquid from said cylinder, a motor, means connecting said motor to said piston to enable said motor to reciprocate said piston, means for detecting a pressure change in saiD cylinder, a first differential amplifier, a second differential amplifier, a rotary speed control circuit, a tacho generator, a reference voltage generator, means connecting said pressure detecting means to a first input of said first differential amplifier, means connecting said reference voltage generator to the second input of said first differential amplifier, means connecting the output of said first differential amplifier to a first input of said second differential amplifier, means connecting said tacho generator to the second input of said second differential amplifier, means connecting said motor to said tacho generator, means connecting the output of said second differential amplifier to the input of said rotary speed control circuit, means connecting the output of said rotary speed control circuit to the input of said motor.
Claim 10
Independent Claim
185 words
A system for supplying a liquid at constant pressure comprising: a cylinder having an inlet and an outlet, a piston reciprocably disposed within said cylinder for drawing liquid into and discharging liquid from said cylinder, a motor, means connecting said motor to said piston to enable said motor to reciprocate said piston, means for detecting a pressure change in saiD cylinder, a first differential amplifier, a second differential amplifier, a rotary speed control circuit, a tacho generator, a reference voltage generator, means connecting said pressure detecting means to a first input of said first differential amplifier, means connecting said reference voltage generator to the second input of said first differential amplifier, means connecting the output of said first differential amplifier to a first input of said second differential amplifier, means connecting said tacho generator to the second input of said second differential amplifier, means connecting said motor to said tacho generator, means connecting the output of said second differential amplifier to the input of said rotary speed control circuit, means connecting the output of said rotary speed control circuit to the input of said motor.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-11-11 | 1978-05-13 | 1978-11-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-11-11 | 1982-05-13 | 1982-11-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-11-11 | 1986-05-13 | 1986-11-12 | $7700.00 | Window Closed / Lapsed |