US5301514A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Low refrigerant charge detection by monitoring thermal expansion valve oscillation
Assignee: General Electric Co
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Filing: 1992-12-02
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Granted: 1994-04-12
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Expires: 2012-12-02
Abstract
Abstract Low refrigerant charge in a refrigeration system is detected by monitoring the oscillation of the thermal expansion valve. This monitoring is accomplished with a sensor which senses the oscillation of the expansion valve and produces a signal indicative of the valve oscillation. The sensor signal is fed to a monitoring controller which produces a low charge signal whenever the amplitude of valve oscillation falls below a predetermined level, thus indicating low charge conditions. The sensor is preferably a temperature sensor situated at either the outlet or the inlet of the evaporator. The system further comprises a validity evaluation controller for determining when valve oscillation is a valid indication of low charge. The validity evaluation controller analyzes a number of system operating characteristics which affect valve oscillation. If the analysis of these characteristics suggests that valve oscillation will produce a valid indication of low charge, then the validity evaluation controller will activate the monitoring controller. Otherwise, the monitoring controller will not be activated.
Inventors
- 👤 Warren F. Bessler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 06:14
CPC Classifications
G; G01; G01F; G01F23/00; G01F23/22; B; B60; B60H; B60H1/00; B60H1/32; B60H1/3204; B60H1/3225; F; F25; F25B; F25B49/00; F25B49/005; F25B2500/00; F25B2500/22; F25B2500/222
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
76 words
A low refrigerant charge detecting system for a refrigeration system having an evaporator, a compressor and an expansion valve, said low refrigerant charge detecting system comprising: a sensor for sensing the oscillation of said expansion valve, said sensor producing a sensor signal indicative of expansion valve oscillation; and a first controller for monitoring said sensor signal, said first controller producing a low charge signal whenever the amplitude of said sensor signal falls below a predetermined level.
Claim 2
Dependent Claim
76 words
A low refrigerant charge detecting system for a refrigeration system having an evaporator, a compressor and an expansion valve, said low refrigerant charge detecting system comprising: a sensor for sensing the oscillation of said expansion valve, said sensor producing a sensor signal indicative of expansion valve oscillation; and a first controller for monitoring said sensor signal, said first controller producing a low charge signal whenever the amplitude of said sensor signal falls below a predetermined level.
Claim 3
Dependent Claim
33 words
The low refrigerant charge detecting system of claim 1 wherein said sensor is a temperature sensor situated at the outlet of said evaporator so that said sensor signal represents the evaporator outlet temperature.
Claim 4
Dependent Claim
27 words
The low refrigerant charge detecting system of claim 2 wherein said first controller is connected to said compressor so that said low charge signal deactivates said compressor.
Claim 5
Dependent Claim
27 words
The low refrigerant charge detecting system of claim 2 further comprising an indicator connected to said first controller so that said low charge signal activates said indicator.
Claim 6
Dependent Claim
33 words
The low refrigerant charge detecting system of claim 1 wherein said sensor is a temperature sensor situated at the inlet of said evaporator so that said sensor signal represents the evaporator inlet temperature.
Claim 7
Dependent Claim
27 words
The low refrigerant charge detecting system of claim 5 wherein said first controller is connected to said compressor so that said low charge signal deactivates said compressor.
Claim 8
Dependent Claim
27 words
The low refrigerant charge detecting system of claim 5 further comprising an indicator connected to said first controller so that said low charge signal activates said indicator.
Claim 9
Dependent Claim
60 words
The low refrigerant charge detecting system of claim 1 further comprising a second controller for determining when expansion valve oscillation is a valid indication of low charge, said first controller being connected to said second controller so as to monitor expansion valve oscillation only when said second controller determines that expansion valve oscillation is a valid indication of low charge.
Claim 10
Dependent Claim
25 words
The low refrigerant charge detecting system of claim 8 wherein said second controller receives input of a plurality of operating characteristics of the refrigeration system.
Claim 11
Independent Claim
51 words
A method for detecting low refrigerant charge in a refrigeration system having an evaporator, a compressor and an expansion valve, said method comprising the steps of: monitoring the oscillation of said expansion valve; and producing a low charge signal whenever the level of expansion valve oscillation falls below a predetermined level.
Claim 12
Independent Claim
51 words
A method for detecting low refrigerant charge in a refrigeration system having an evaporator, a compressor and an expansion valve, said method comprising the steps of: monitoring the oscillation of said expansion valve; and producing a low charge signal whenever the level of expansion valve oscillation falls below a predetermined level.
Claim 13
Dependent Claim
24 words
The method of claim 10 wherein said step of monitoring the oscillation of said expansion valve comprises monitoring the outlet temperature of said evaporator.
Claim 14
Dependent Claim
13 words
The method of claim 11 wherein said low charge signal deactivates said compressor.
Claim 15
Dependent Claim
13 words
The method of claim 11 wherein said low charge signal activates an indicator.
Claim 16
Dependent Claim
24 words
The method of claim 10 wherein said step of monitoring the oscillation of said expansion valve comprises monitoring the inlet temperature of said evaporator.
Claim 17
Dependent Claim
13 words
The method of claim 14 wherein said low charge signal deactivates said compressor.
Claim 18
Dependent Claim
13 words
The method of claim 14 wherein said low charge signal activates an indicator.
Claim 19
Dependent Claim
49 words
The method of claim 10 further comprising the step of determining when expansion valve oscillation is a valid indication of low charge, and only performing said step of monitoring the oscillation of said expansion valve when expansion valve oscillation is found to be a valid indication of low charge.
Claim 20
Dependent Claim
32 words
The method of claim 17 wherein said step of determining when expansion valve oscillation is a valid indication of low charge comprises analyzing a plurality of operating characteristics of the refrigeration system.
Claim 21
Independent Claim
88 words
A method for detecting low refrigerant charge in a refrigeration system having an evaporator, a compressor and an expansion valve, said method comprising the steps of: analyzing a plurality of operating characteristics of the refrigeration system to determine whether high evaporator exit superheat is a valid indication of low charge; monitoring evaporator exit superheat whenever said analyzing step finds that high evaporator exit superheat is a valid indication of low charge; and producing a low charge signal whenever the level of evaporator exit superheat exceeds a predetermined level.
Claim 22
Independent Claim
88 words
A method for detecting low refrigerant charge in a refrigeration system having an evaporator, a compressor and an expansion valve, said method comprising the steps of: analyzing a plurality of operating characteristics of the refrigeration system to determine whether high evaporator exit superheat is a valid indication of low charge; monitoring evaporator exit superheat whenever said analyzing step finds that high evaporator exit superheat is a valid indication of low charge; and producing a low charge signal whenever the level of evaporator exit superheat exceeds a predetermined level.
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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) | 1997-04-11 | 1997-10-11 | 1998-04-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-04-11 | 2001-10-11 | 2002-04-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-04-11 | 2005-10-11 | 2006-04-12 | $7700.00 | Window Closed / Lapsed |