Patent US5240380A successfully refreshed from Google Patents.
US5240380A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Variable speed control for centrifugal pumps
Assignee: Sundyne LLC
•
Filing: 1991-05-21
•
Granted: 1993-08-31
•
Expires: 2011-05-21
Abstract
Abstract A control system (10) for a variable speed centrifugal pump (12) in which pump pressure as a function of flow rate for a constant speed of operation of the pump has a range of flow rates in which the pump pressure increases as a function of increasing flow rate which is unstable in accordance with the invention includes a sensor (14) for sensing an operational parameter of an output flow pumped by the pump; a variable speed drive (16) for driving the pump at a commanded rotational speed in response to a commanded speed signal; and a controller (22), responsive to the sensed operational parameter, for producing the commanded speed signal (N) as a function of pump speeds at which the pump pressure does not increase with increasing flow rate.
Inventors
- 👤 William J. Mabe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 00:43
CPC Classifications
F; F04; F04D; F04D15/00; F04D15/0066
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
192 words
A control system for a variable speed centrifugal pump operative throughout a flow range extending from a minimum to a maximum flow rate in which pump pressure as a function of flow rate for a constant speed of operation of the pump has a range of flow rates in which the pump pressure increases as a function of increasing flow rate which is unstable comprising: a sensor in fluid communication with output flow pumped from the pump for sensing only a single operational parameter of the output flow pumped by the pump; a variable speed drive for driving the pump at a commanded rotational speed in response to a commanded speed signal; and a controller, responsive to the sensed operational parameter, for producing the commanded speed signal as a function of pump flow to vary pump speed from a speed producing the flow rates in which the pump pressure increases as a function of increasing flow rate to the commanded rotational speed to produce pump operation throughout the flow range to produce only flow rates for which pump pressure decreases as a function of increasing flow rate to produce stable pump operation.
Claim 2
Dependent Claim
192 words
A control system for a variable speed centrifugal pump operative throughout a flow range extending from a minimum to a maximum flow rate in which pump pressure as a function of flow rate for a constant speed of operation of the pump has a range of flow rates in which the pump pressure increases as a function of increasing flow rate which is unstable comprising: a sensor in fluid communication with output flow pumped from the pump for sensing only a single operational parameter of the output flow pumped by the pump; a variable speed drive for driving the pump at a commanded rotational speed in response to a commanded speed signal; and a controller, responsive to the sensed operational parameter, for producing the commanded speed signal as a function of pump flow to vary pump speed from a speed producing the flow rates in which the pump pressure increases as a function of increasing flow rate to the commanded rotational speed to produce pump operation throughout the flow range to produce only flow rates for which pump pressure decreases as a function of increasing flow rate to produce stable pump operation.
Claim 3
Dependent Claim
17 words
A control system in accordance with claim 1 wherein: the pump has an impeller with radial blades.
Claim 4
Dependent Claim
53 words
A control system in accordance with claim 1 wherein the variable speed drive comprises: a variable speed electric motor for driving the centrifugal pump; and an electrical power drive for supplying an electrical power signal to the variable speed electric motor to cause the electric motor to rotate at the commanded rotational speed.
Claim 5
Dependent Claim
15 words
A control system in accordance with claim 1 wherein: the operational parameter is flow rate.
Claim 6
Dependent Claim
41 words
A control system in accordance with claim 1 wherein: the controller utilizes an equation expressing pump speed as a function of flow rate which is solved by the controller in response to the operational parameter to produce the commanded speed signal.
Claim 7
Dependent Claim
15 words
A control system in accordance with claim 5 wherein: the operational parameter is flow rate.
Claim 8
Dependent Claim
55 words
A control system in accordance with claim 1 wherein: the controller utilizes a table of individual speeds each associated with a flow rate with the controller producing the commanded speed signal by matching the operational parameter to a flow rate and outputting the speed, associated with the matched flow rate, as the commanded speed signal.
Claim 9
Dependent Claim
15 words
A control system in accordance with claim 7 wherein: the operational parameter is flow rate.
Claim 10
Independent Claim
197 words
A system comprising: a variable speed centrifugal pump operative throughout a flow range extending from a minimum to a maximum flow rate in which pump pressure as a function of flow rate for a constant speed of operation of the pump has a range of flow rates in which the pump pressure increases as a function of increasing flow rate which is unstable; a sensor in fluid communication with output flow pumped from the pump for sensing only a single operational parameter of the output flow pumped by the pump; a variable speed drive for driving the pump at a commanded rotational speed in response to a commanded speed signal; and a controller, responsive to the sensed operational parameter, for producing the commanded speed signal to vary the speed of the pump as a function of pump flow to vary pump speed from a speed producing the flow rates in which the pump pressure increases as a function of increasing flow rate to the commanded rotational speed to produce pump operation throughout the flow range to produce only flow rates for which pump pressure decreases as a function of increasing flow rate to produce stable pump operation.
Claim 11
Independent Claim
197 words
A system comprising: a variable speed centrifugal pump operative throughout a flow range extending from a minimum to a maximum flow rate in which pump pressure as a function of flow rate for a constant speed of operation of the pump has a range of flow rates in which the pump pressure increases as a function of increasing flow rate which is unstable; a sensor in fluid communication with output flow pumped from the pump for sensing only a single operational parameter of the output flow pumped by the pump; a variable speed drive for driving the pump at a commanded rotational speed in response to a commanded speed signal; and a controller, responsive to the sensed operational parameter, for producing the commanded speed signal to vary the speed of the pump as a function of pump flow to vary pump speed from a speed producing the flow rates in which the pump pressure increases as a function of increasing flow rate to the commanded rotational speed to produce pump operation throughout the flow range to produce only flow rates for which pump pressure decreases as a function of increasing flow rate to produce stable pump operation.
Claim 12
Dependent Claim
15 words
A control system in accordance with claim 9 wherein: the operational parameter is flow rate.
Claim 13
Dependent Claim
55 words
A control system in accordance with claim 1 wherein: the controller utilizes a table of individual speeds each associated with a flow rate with the controller producing the commanded speed signal by matching the operational parameter to a flow rate and outputting the speed, associated with the matched flow rate, as the commanded speed signal.
Claim 14
Dependent Claim
15 words
A control system in accordance with claim 11 wherein: the operational parameter is flow rate.
Claim 15
Dependent Claim
41 words
A control system in accordance with claim 9 wherein: the controller utilized an equation expressing pump speed as a function of flow rate which is solved by the controller in response to the operational parameter to produce the commanded speed signal.
Claim 16
Dependent Claim
15 words
A control system in accordance with claim 13 wherein: the operational parameter is flow rate.
References Cited (Backward Citations)
GB1140128A
Cited
US3551072A
Cited
US4201925A
Cited
US4108574A
Cited
US4382745A
Cited
US4253794A
Cited
US4212590A
Cited
US4354800A
Cited
US4248194A
Cited
US4474528A
Cited
US4370098A
Cited
US4595342A
Cited
GB2124304A
Cited
US4610599A
Cited
US4678404A
Cited
JPS61149583A
Cited
US4708594A
Cited
JPS61173698A
Cited
JPS61175271A
Cited
JPS6218069A
Cited
US4694189A
Cited
US4754156A
Cited
US5026256A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-08-30 | 1997-03-01 | 1997-08-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-08-30 | 2001-03-01 | 2001-08-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-08-30 | 2005-03-01 | 2005-08-31 | $7700.00 | Window Closed / Lapsed |