US5490394A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fan control system for the evaporator of refrigerating appliances
Assignee: Whirlpool SA
•
Filing: 1994-09-23
•
Granted: 1996-02-13
•
Expires: 2014-09-23
Abstract
Abstract A fan control system for the evaporator of refrigerating appliances, of the type in which the internal air is forced to circulate, by action of a fan (20), through the evaporator (30) of a refrigerating circuit, fed by a compressor (40), the system comprising: a first temperature sensing means (S1), detecting the temperature of the circulating air at the air inlet of the evaporator (30); a second temperature sensing means (S2), detecting the temperature of the evaporator (30); and a control circuit (50), producing: a fan stop control signal, when the difference between the values of the temperatures detected by the first and second sensors (S1, S2) reaches a stop value, below which the heat transfer from the forced circulating air to the evaporator is lower than the heat transfer from the fan (20) to the air; and a fan start control signal, when the difference of temperatures reaches a certain start value corresponding to a temperature of the evaporator (30) substantially lower than the temperature of the air in the internal medium.
Inventors
- 👤 Marco E. Marques
- 👤 Roberto D. Brun
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 05:56
CPC Classifications
F; F25; F25D; F25D17/00; F25D17/04; F25D17/06; F25B; F25B2600/00; F25B2600/11; F25B2600/112; F25B2700/00; F25B2700/21; F25B2700/2117; F25B2700/21171; F25B2700/21172; F25D2700/00; F25D2700/02; Y; Y02; Y02B; Y02B40/00
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
205 words
A fan control system for the evaporator of refrigerating appliances, of the type in which the internal air is forced to circulate, by action of a fan, through the evaporator of a refrigerating circuit, fed by a compressor comprising: a first temperature sensing means disposed to detect the temperature of the air inside the refrigerating appliance at the air inlet of the evaporator; a second temperature sensing means disposed to detect the temperature of the evaporator; a control circuit, operatively connected to said first and second temperature sensors and to said fan and producing, in response to the temperature values detected by said sensors: a fan stop control signal, when the difference between the values of the temperature detected by said first and second sensors reaches a stop value, below which the heat transfer from the forced circulating air to the evaporator is lower than the heat transfer from said fan to said air; and a fan start control signal, when said difference between the temperature values reaches, with the reduction of the temperature of the evaporator, due to the compressor operation, a certain start value corresponding to a temperature of the evaporator substantially lower than the temperature of the air in the internal medium.
Claim 2
Dependent Claim
205 words
A fan control system for the evaporator of refrigerating appliances, of the type in which the internal air is forced to circulate, by action of a fan, through the evaporator of a refrigerating circuit, fed by a compressor comprising: a first temperature sensing means disposed to detect the temperature of the air inside the refrigerating appliance at the air inlet of the evaporator; a second temperature sensing means disposed to detect the temperature of the evaporator; a control circuit, operatively connected to said first and second temperature sensors and to said fan and producing, in response to the temperature values detected by said sensors: a fan stop control signal, when the difference between the values of the temperature detected by said first and second sensors reaches a stop value, below which the heat transfer from the forced circulating air to the evaporator is lower than the heat transfer from said fan to said air; and a fan start control signal, when said difference between the temperature values reaches, with the reduction of the temperature of the evaporator, due to the compressor operation, a certain start value corresponding to a temperature of the evaporator substantially lower than the temperature of the air in the internal medium.
Claim 3
Dependent Claim
36 words
The fan control system, as in claim 1, wherein the control circuit is connected to the fan through a switch that interrupts the supply to the fan when the door of the refrigerating appliance is opened.
Claim 4
Dependent Claim
61 words
The fan control system, as in any of the claims 1 or 2, wherein the control circuit comprises: a differential amplifier operatively connected to both the first and second temperature sensors, to transform the difference of the temperatures detected by said sensors into a voltage signal; and a thermostat circuit connected to both the output of the differential amplifier and fan.
Claim 5
Dependent Claim
64 words
The fan control system, as in claim 3, wherein the differential amplifier is formed by a first operational amplifier, connected to both the first and second temperature sensors through a pair of first resistors disposed parallely with a pair of second resistors, one of them being in series with a grounded potentiometer and the other connected to the output of the first operational amplifier.
Claim 6
Dependent Claim
38 words
The fan control system, as in claim 4, wherein both sensors are defined by two NTCs which, together with a pair of respective third grounded resistors form a resistive bridge to the input of the first operational amplifier.
Claim 7
Dependent Claim
36 words
The fan control system, as in claim 4, wherein the thermostat circuit includes a second operational amplifier disposed in series with fourth and seventh resistors and parallel to a fifth resistor and a sixth grounded resistor.
Claim 8
Dependent Claim
51 words
The fan control system, as in claim 6, wherein the fan includes a switching circuit formed by a transistor with its base connected to the output of the second operational amplifier through an eighth resistor, said transistor being grounded and connected to the coil of a relay for energizing the fan.
Claim 9
Dependent Claim
65 words
A fan control system, as in claim 2, characterized in that the control circuit (50) comprises: a differential amplifier (51) operatively connected to both the first and second temperature sensors (S1, S2), to transform the difference of the temperatures detected by said sensors into a voltage signal; and a thermostat circuit (52) connected to both the output of the differential amplifier (51) and fan (20).
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-02-12 | 1999-08-14 | 2000-02-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-02-12 | 2003-08-14 | 2004-02-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-02-12 | 2007-08-14 | 2008-02-13 | $7700.00 | Window Closed / Lapsed |