JPS6330932Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a refrigerator abnormality detection and protection device in a refrigeration system.

Conventionally, in low-temperature refrigerators, abnormalities have been detected mainly as mechanical damage (e.g. piston and cylinder galling, supply and exhaust valve abnormalities, "0" ring seal abnormality), judgment by sound, rotation Abnormal numbers,
This was due to an abnormality in the pressure inside the refrigerator.

Most of these methods require experience in operating a refrigerator, or detect abnormal signals due to serious damage.

The present invention aims to improve these points and provide a refrigerator abnormality detection and protection device that can be easily used by anyone and detects abnormalities in the initial state.

A refrigerator generates low-temperature refrigerant using a combination of a heat exchanger and an adiabatic expansion engine. At this time, the energy possessed by the refrigerant must be extracted to the outside during the adiabatic expansion process by the adiabatic expansion engine for consumption, that is, power absorption.

The magnitude of this absorbed power (calculated value on the refrigerator heat balance) is always constant. On the other hand, the mechanical loss inside the refrigerator (normal state) is almost constant.

Therefore, if the refrigerator is operating normally,
The difference between the amount of absorbed power on the heat balance and the mechanical loss (referred to as the actual absorbed power) is consumed on the generator load side to keep the rotation speed constant.

Therefore, the rotational speed fluctuates when the amount of absorbed power becomes less than the mechanical loss or, conversely, increases significantly and exceeds the maximum load of the power absorption adjustment section 4. The output voltage of the generator also fluctuates only by the armature coil resistance voltage drop within the generator.

Conventionally, the actual power absorption amount was "0" for the rotation speed and generator output voltage that were monitored for abnormality detection.
An abnormality cannot be detected until the loss becomes so large that it becomes .

In the present invention, a signal is monitored using the generator output current so that a change in the actual amount of absorbed power can be detected immediately. This will be explained using figures.

Fig. 1 schematically shows that the generator output in the power absorption part 2 that absorbs the power of the refrigerator 1 is rectified into direct current by the rectifier 3, ) and enters load 5. An abnormality detection unit protection device 6 is installed in parallel with the load 5.

FIG. 2 shows an example of the abnormality detection and protection device 6.

The output current from the power absorbing section 2 that is input to the load 5 returns via a diode 7 and a relay 8 that are connected in parallel with the load 5. When the adiabatic expansion engine rotates, there is rotational unevenness within one rotation, which causes ripples in the generator output that are synchronized with the rotational speed. Therefore, a smoothing circuit with an appropriate time constant is connected to the relay 8 using a capacitor 9 and a resistor 10. Relay 8 installed in parallel
This ensures that the voltage applied to the circuit is not affected by ripple.

The output of the generator is consumed by the load 5 via the rectifier 3 and the power absorption adjustment section 4, and when the voltage across the load 5 rises and exceeds the drive voltage of the relay 8, the relay 8 is activated. Since the relay 8 has a large hysteresis in the ON-OFF operation of the relay 8, the operation of the relay 8 is maintained even if the voltage across the relay 8 drops somewhat after the relay 8 is activated.

This voltage activates or deactivates the relay 8 to perform a protective operation (for example, turning off the compressor power, closing the gas supply valve, etc.).

As is clear from the above description, by using the refrigerator abnormality detection and protection device according to the present invention, abnormalities in the initial state can be easily detected and serious accidents can be prevented from occurring.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a refrigerator provided with a refrigerator abnormality detection and protection device according to the present invention, and FIG. 2 is a specific circuit diagram of the refrigerator abnormality detection and protection device. DESCRIPTION OF SYMBOLS 1... Refrigerator, 2... Power absorption part, 3... Rectifier, 5... Load, 6... Abnormality detection protection device, 7...
...Diode, 8...Relay, 9...Resistor, 10
...Capacitor.

Claims (1)

[Scope of utility model registration request] A diode and 1. A refrigerator abnormality detection and protection device comprising: a circuit connected in series with a relay; and a smoothing circuit connected in parallel with the relay.