US5240380A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Variable speed control for centrifugal pumps
Assignee: Sundyne LLC
•
Filing: 1991-05-21
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Granted: 1993-08-31
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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 00:30
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.
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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) | 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 |