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 Title: |
US6101827:
Temperature comparison circuit and refrigeration expansion valve
[ Derwent Title ]
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| Country: |
US United States of America
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| Inventor: |
Burson, Benard; Austin, TX 78757
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| Assignee: |
None
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| Published / Filed: |
2000-08-15
/ 1999-11-08
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| Application Number: |
US1999000436028
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| IPC Code: |
Advanced:
F25B 41/06;
Core:
more...
IPC-7:
F25B 41/04;
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| ECLA Code: |
F25B41/06B;
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| U.S. Class: |
Current:
062/210;
062/224;
251/129.21;
318/641;
Original:
062/210;
062/224;
251/129.21;
318/641;
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| Field of Search: |
062/208,209,210,211,212,222,223,224,225
236/92 B
251/129.01,129.08,129.09,129.1,129.15,129.16,129.21
318/638,639,641,677,678,681,686,687
374/183,185
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| Priority Number: |
| 1999-11-08 |
US1999000436028 |
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| Abstract: |
Temperature comparison circuits which utilize two thermistors which are initially set up in a balanced bridge using NPN transistors and resistors. As temperature differences between the thermistors cause the bridge to become unbalanced, there is a current flow in which the voltage varies in magnitude and direction. The circuits are attached to electrical equipment which is sensitive to changes in magnitude and direction of voltage. The circuits find uses in controlling refrigeration systems, controlling heating and cooling systems, and performing diagnostic tests on mammals or devices which contain temperature differences between two separate points. The circuits may be used in cooperation with an expansion valve which is located in the tubing of a refrigeration system. The tubing is non-magnetic. There is a fixed magnetizable plate having a central orifice. There is a moveable magnetizable plunger having an end which may fit into the central orifice to create a closure of the valve or may be withdrawn from the central orifice to open the valve. The outside of the tube over the plate is wound with a line which is connected to the temperature-sensitive circuit. The outside of the tube over the plunger is wound with a line carrying constant voltage. As the circuit voltage changes in response to temperature differences between the thermistors, the polarity of the fixed plate varies and either attracts or repels the plunger.
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| Attorney, Agent or Firm: |
Huff, Richard L. ;
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| Primary / Asst. Examiners: |
Tanner, Harry B.;
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| Maintenance Status: |
E2 Expired Check current status
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| INPADOC Legal Status: |
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| Family: |
None
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First Claim:
Show all 15 claims |
I claim:
1. Temperature comparison circuitry comprising: positive and negative connectors adapted to be connected to a supply of positive and negative electrical power;
- a first thermistor coupled to the positive connector;
- a second thermistor coupled to the positive connector;
- a first high-gain NPN transistor having a collector, an emitter, and a base coupled between the first thermistor and the positive connector by a first line, the collector of the transistor being coupled with the positive connector;
- a second high-gain NPN transistor having a collector, an emitter, and a base coupled between the second thermistor and the positive connector by a second line, the collector of the transistor being coupled with the positive connector; a potentiometer coupled between the emitters of the first and second NPN transistors and coupled to the negative connector;
- a first connection point between the first NPN transistor and the potentiometer;
- a second connection point between the second NPN transistor and the potentiometer;
- a third line running from the first connection point;
- a fourth line running from the second connection point, which third and fourth lines are
- adapted to be connected to a piece of electrical equipment which is sensitive to a change in voltage;
- a first fixed-value resistor coupled between the first line at a point between the first thermistor and the first NPN transistor and the third line; and
- a second fixed-value resistor coupled between the second line at a point between the second thermistor and the second NPN transistor and the fourth line.
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| Background / Summary: |
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| Drawing Descriptions: |
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| Description: |
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| Forward References: |
Show 3 U.S. patent(s) that reference this one
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