US5580221A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Motor drive circuit for pressure control of a pumping system
Assignee: Franklin Electric Co Inc
•
Filing: 1994-10-05
•
Granted: 1996-12-03
•
Expires: 2014-10-05
Abstract
Abstract This disclosure relates to a liquid supply system including a motor-pump unit designed for installation in a liquid supply such as a well or storage tank. The unit supplies the liquid to a supply pipe, and a pressure sensor connected to the pipe is operable to provide a control signal representative of the liquid pressure in the pipe. The motor is a variable-speed AC motor. A control for the motor is responsive to the control signal and actuates a power circuit to drive the motor at a speed adjusted to maintain the liquid pressure at a substantially constant value. The control circuit further includes means for turning off the power to the motor in the absence of flow through pipe, which does not require a flow sensor. The power circuit comprises a DC link including a rectifier and an inverter. The rectifier is located adjacent the pressure sensor; the inverter may be located adjacent the rectifier and the pressure sensor or in the casing of the motor-pump unit.
Inventors
- 👤 David M. Triezenberg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 14:37
CPC Classifications
G; G05; G05D; G05D16/00; G05D16/20; G05D16/2006; G05D16/2066; F; F04; F04B; F04B47/00; F04B47/06; F04B49/00; F04B49/02; F04B49/022; F04B49/06; F04B49/08; F04D; F04D15/00; F04D15/0066; F04B2205/00; F04B2205/05; F04B2207/00; F04B2207/70; F04B2207/703
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
209 words
A liquid supply system comprising a) a motor-pump unit including a variable speed electric motor; b) a pipe connected to said unit for conveying liquid pumped by said unit; c) a pressure sensor connected to said pipe for providing a pressure signal representative of the liquid pressure in said pipe; and d) unit operating apparatus responsive to said pressure signal and connected to said unit for operating said unit, said apparatus comprising 1) speed control means for operating said unit in a first mode wherein the speed of said unit is adjusted to maintain a substantially constant pressure in said pipe, said speed control means being connected to said pressure sensor and to said unit; 2) speed change means for operating said unit in a second mode wherein the speed of said unit is reduced; 3) pressure monitoring means responsive to said pressure sensor for providing an indication of a drop of pressure in said pipe; and 4) intermittent means connected to said monitoring means for normally operating said unit in said first mode, for intermittently operating said unit in said second mode, and for turning off said unit when said monitoring means fails to indicate a drop of pressure when said unit is operating in said second mode.
Claim 2
Dependent Claim
209 words
A liquid supply system comprising a) a motor-pump unit including a variable speed electric motor; b) a pipe connected to said unit for conveying liquid pumped by said unit; c) a pressure sensor connected to said pipe for providing a pressure signal representative of the liquid pressure in said pipe; and d) unit operating apparatus responsive to said pressure signal and connected to said unit for operating said unit, said apparatus comprising 1) speed control means for operating said unit in a first mode wherein the speed of said unit is adjusted to maintain a substantially constant pressure in said pipe, said speed control means being connected to said pressure sensor and to said unit; 2) speed change means for operating said unit in a second mode wherein the speed of said unit is reduced; 3) pressure monitoring means responsive to said pressure sensor for providing an indication of a drop of pressure in said pipe; and 4) intermittent means connected to said monitoring means for normally operating said unit in said first mode, for intermittently operating said unit in said second mode, and for turning off said unit when said monitoring means fails to indicate a drop of pressure when said unit is operating in said second mode.
Claim 3
Dependent Claim
56 words
A system as set forth in claim 1, wherein said speed control means includes means for providing a setting of a desired pressure in said pipe, means for combining said setting with pressure signal to form an error signal, and a control circuit for adjusting said speed of said unit to substantially eliminate said error signal.
Claim 4
Dependent Claim
27 words
A system as set forth in claim 1, wherein said speed change means comprises a ramp generator circuit for reducing the speed of said unit to zero.
Claim 5
Dependent Claim
36 words
A system as set forth in claim 1, wherein said pressure monitoring means provides said indication of a drop of pressure and forms a second indication of the derivative with time of a drop of pressure.
Claim 6
Dependent Claim
26 words
A system as set forth in claim 4, wherein said pressure monitoring means further includes means for comparing said indication and said second indication with limits.
Claim 7
Dependent Claim
28 words
A system as set forth in claim 4, wherein said intermittent means comprises a resettable timer connected to be reset by either said indication or said second indication.
Claim 8
Dependent Claim
60 words
A system as set forth in claim 6, wherein said timer has a timing period during which said unit is operated in said first mode and said timer, said timer switching said unit to operation in said second mode at the end of said timing period, and said timer being reset by either said indication or by said second indication.
Claim 9
Dependent Claim
19 words
A system as set forth in claim 1, wherein said pipe is connected to a relatively small accumulator tank.
Claim 10
Dependent Claim
143 words
A liquid supply system comprising a) a motor-pump unit including a variable speed electric motor; b) a pipe connected to said unit for conveying liquid pumped by said unit; c) a pressure sensor connected to said pipe for providing a pressure signal representative of the liquid pressure in said pipe; and d) apparatus responsive to said pressure signal and to said unit for operating said unit, said apparatus comprising 1) speed control means responsive to said pressure signal and connected to said unit for operating said unit to maintain a substantially constant pressure in said pipe; 2) speed change means periodically connected to said unit for reducing the speed of said unit; and 3) pressure monitoring means responsive to said pressure signal for turning off said unit if a periodic reduction in the speed of said unit does not produce a pressure drop.
Claim 11
Dependent Claim
143 words
A liquid supply system comprising a) a motor-pump unit including a variable speed electric motor; b) a pipe connected to said unit for conveying liquid pumped by said unit; c) a pressure sensor connected to said pipe for providing a pressure signal representative of the liquid pressure in said pipe; and d) apparatus responsive to said pressure signal and to said unit for operating said unit, said apparatus comprising 1) speed control means responsive to said pressure signal and connected to said unit for operating said unit to maintain a substantially constant pressure in said pipe; 2) speed change means periodically connected to said unit for reducing the speed of said unit; and 3) pressure monitoring means responsive to said pressure signal for turning off said unit if a periodic reduction in the speed of said unit does not produce a pressure drop.
References Cited (Backward Citations)
US2440981A
Cited
US3013186A
Cited
US3141998A
Cited
US3136924A
Cited
US3551072A
Cited
US3685926A
Cited
US5197859A
Cited
US3692430A
Cited
US3719860A
Cited
US3855515A
Cited
US4037045A
Cited
US3985467A
Cited
US4051509A
Cited
US4120019A
Cited
US4204246A
Cited
US4093971A
Cited
US4155402A
Cited
US4102394A
Cited
US4145161A
Cited
US4196775A
Cited
EP0004056A1
Cited
US4247260A
Cited
US4281968A
Cited
US4284943A
Cited
US4225290A
Cited
US4344741A
Cited
US4257395A
Cited
US4329120A
Cited
US4442953A
Cited
US4397610A
Cited
US4396353A
Cited
US5040126A
Cited
US4433219A
Cited
US4460355A
Cited
US4532893A
Cited
US4678404A
Cited
US4788448A
Cited
US4686439A
Cited
US4627243A
Cited
US4733152A
Cited
US4834624A
Cited
US4805118A
Cited
US4795314A
Cited
US4841404A
Cited
US4840068A
Cited
US4874294A
Cited
EP0390627A1
Cited
US5015151A
Cited
US5244350A
Cited
US4987953A
Cited
US5092824A
Cited
US5064347A
Cited
US5145323A
Cited
US5238369A
Cited
US5240380A
Cited
US5282722A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-12-03 | 2000-06-03 | 2000-12-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-12-03 | 2004-06-03 | 2004-12-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-12-03 | 2008-06-03 | 2008-12-03 | $7700.00 | Window Closed / Lapsed |