US5158436A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Pump with speed controller responsive to temperature
Assignee: Grundfos AS
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Filing: 1991-03-12
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Granted: 1992-10-27
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Expires: 2011-03-12
Abstract
Abstract The pump unit is provided, in particular for heating and cooling installations. The speed of the pump unit may be altered by changing the operating frequency of a frequency converter feeding the electric motor and which forms a structural unit with the pump unit. As soon as the pump unit has reached a parameter characterizing the thermal overload of the same, the frequency converter is controlled in a manner so as to reduce the speed, the reduced speed n' being greater or equal to half the normal speed n.
Inventors
- 👤 Niels D. Jensen
- 👤 Ivan Knudsen
- 👤 Bjarne D. Pedersen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 20:37
CPC Classifications
H; H02; H02H; H02H7/00; H02H7/08; H02H7/0833; F; F04; F04D; F04D15/00; F04D15/0066; F04D15/0077; H02H7/085; H02H7/0852; H02H7/0856; H02H7/0858
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
84 words
Pump unit, in lar for heating and cooling installations, the speed of which can be altered by changing the operating frequency of a frequency converter feeding the electric motor, and having a device which protects the unit from thermal overload, the pump unit and frequency converter forming a structural unit, characterised in that when a parameter characterising the overload state is reached, the motor speed n is reduced to a motor speed n' by driving the frequency converter, wherein the relationship n'≧0.5 n applies.
Claim 2
Dependent Claim
84 words
Pump unit, in lar for heating and cooling installations, the speed of which can be altered by changing the operating frequency of a frequency converter feeding the electric motor, and having a device which protects the unit from thermal overload, the pump unit and frequency converter forming a structural unit, characterised in that when a parameter characterising the overload state is reached, the motor speed n is reduced to a motor speed n' by driving the frequency converter, wherein the relationship n'≧0.5 n applies.
Claim 3
Dependent Claim
17 words
Pump unit according to claim 1, wherein the parameter characterising the overload state is a limiting temperature.
Claim 4
Dependent Claim
25 words
Pump unit according to claim 2, wherein the limiting temperature is determined by means of a highest permissible temperature of a winding in the stator.
Claim 5
Dependent Claim
20 words
Pump unit according to claim 3, wherein the temperature of the winding is determined by measuring the electrical winding resistance.
Claim 6
Dependent Claim
23 words
Pump unit according to claim 2, wherein the limiting temperature is determined by means of a highest permissible storage temperature for the unit.
Claim 7
Dependent Claim
24 words
Pump unit according to claim 2, wherein the limiting temperature is determined by means of a highest permissible temperature in the converter electronic mechanism.
Claim 8
Dependent Claim
27 words
Pump unit according to claim 6, wherein the limiting temperature is determined by means of a highest permissible temperature in the power part of the frequency converter.
Claim 9
Dependent Claim
26 words
Pump unit according to claim 1, wherein the motor speed is also reduced when a predetermined temperature of the fluid conveyed through the pump is reached.
Claim 10
Dependent Claim
62 words
Pump unit according to claim 1, wherein the motor speed is raised again to the speed n when a value is lower than the parameter characterising the overload state, the parameter resulting in an increase in speed when it is reached differing from the parameter resulting in a decrease in speed when it is reached, or a dead time element is provided.
References Cited (Backward Citations)
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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) | 1995-10-27 | 1996-04-27 | 1996-10-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-10-27 | 2000-04-27 | 2000-10-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-10-27 | 2004-04-27 | 2004-10-27 | $7700.00 | Window Closed / Lapsed |