Claims
- 1. A valve assembly for a refrigeration plant, comprising, a valve, a reference pressure generator for controlling said valve filled with a liquid vapor medium, a heating resistor in said medium, a first feedback external temperature sensor, a second feedback temperature sensor in said medium, a first bridge circuit including said first temperature sensor and a first operational amplifier, a second bridge circuit including said second temperature sensor and a second operational amplifier, a summating circuit for said bridge circuits including a third amplifier connected to said heating resistor, adjustable resistors at the outputs of said bridge circuits connected to the noninverting input of said third amplifier for varying the relative influence of either of said first and second sensors on said third amplifier and thereby on the regulation of said valve, capacitor means and feed back resistor means in series between the output and the inverting input of said amplifier, voltage divider means between said output and said capacitor forming a voltage divider energized by said output for setting a time delay integration constant for said first amplifier, and variable resistance means between the junction of said feedback resistor means and said capacitor means and ground forming a voltage divider energized by the input voltage to the inverting input for setting the proportionality factor for said first amplifier.
- 2. A valve assembly according to claim 1 wherein said third amplifier is an operation amplifier, said third amplifier having a Darlington amplifier between the output thereof and said heating resistor, and feedback means including a resistor connected between the inverting input of said third amplifier and the junction between said Darlington amplifier and said heating resistor.
Priority Claims (1)
Number |
Date |
Country |
Kind |
2749240 |
Nov 1977 |
DEX |
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Parent Case Info
This application is a continuation of Ser. No. 956,649, filed on Nov. 1, 1978 now abandoned.
US Referenced Citations (8)
Continuations (1)
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Number |
Date |
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Parent |
956649 |
Nov 1978 |
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