JPS6349670Y2 - - Google Patents

Description

[Detailed explanation of the invention] This invention uses a thermostat for temperature control to start defrosting.
This invention relates to a defrosting control device that eliminates wasted power consumption and improves power saving effect by matching the change from OFF to ON.

Figure 1 is an electrical circuit diagram of a defrosting control device used in conventional fan-type refrigerators, where 1 is a power supply, 2 is a defrost timer having a timer motor 2' and a timer contact 2'', and 3 is a temperature inside the refrigerator. A thermostat for temperature adjustment detects the temperature and controls the power supply to compressor 4, 5 is a defrosting heater, 6 is a drain heater for evaporating defrosted water, and 7 is turned off when the temperature near the evaporator rises. 8 is a door switch linked to the opening and closing of the refrigerator door, and 9 is a fan that blows cold air from the evaporator to each part of the refrigerator.

To explain the operation, when timer contact 2'' of defrosting timer 2 is in the solid line state, thermometer 3 is activated.
The timer motor 2' rotates only when it is turned ON and the compressor 4 is energized. If the setting time of the defrosting timer 2 (for example, the time during which the contact 2'' is in the solid line state when the timer motor 2' is continuously energized) is approximately 8 hours, the cumulative operating time of the compressor 4 is approximately 8 hours. When the time comes, the timer contact 2'' of the defrosting timer 2 changes to the state shown by the broken line and enters the defrosting state. That is, the compressor 4 is stopped, the defrosting heater 5 and the drain heater 6 are energized, and the defrosting heater 5 melts the frost adhering to the evaporator (not shown), and the water is evaporated by the drain heater 6. When the frost melts and disappears, the temperature of the evaporator and its surroundings rises, so the differential thermometer 7 is turned off, the defrosting heater 5 is turned off, and the timer motor 2' is energized, so the timer contact 2'' will be turned on after a few minutes. returns to the solid line state (the time for the timer contact 2'' to be in the broken line state is set to be several minutes).

When the timer contact 2'' returns to the solid line state, the compressor 4 starts operating, and the blower fan 9 sends cold air to each part of the refrigerator.The door switch 8 is turned off when the door is opened, and the blower fan is turned off. 9 is stopped to reduce the outflow of cold air to the outside of the warehouse.

The disadvantage of the conventional circuit described above is that compressor 4 is always activated when entering the defrost cycle from normal operation.
Therefore, even though the compressor 4 is operating to cool the evaporator, the defrost heater 5 immediately warms the evaporator for defrosting, which is a waste of electricity. Instead, it takes longer to defrost.
In addition, since the blower fan 9 starts blowing air at the same time that the compressor 4 starts operating after defrosting, there is a drawback that hot air from the evaporator during defrosting is sent to various parts of the refrigerator, reducing the cooling effect.

The present invention has been devised to eliminate the above-mentioned drawbacks, and will be described in detail below based on the illustrated embodiments. Incidentally, the same parts between the present invention and the conventional example are indicated by the same numbers.

FIG. 2 is an electric circuit diagram showing an embodiment of the device of the present invention, in which 10 is a first relay connected in series to a series circuit of a diode 28 and a resistor 29, and when the first relay 10 is energized, the relay switch 1
0' and another relay switch 1.
27 is a transistor whose collector terminal is connected to the first relay 10 and the other power supply terminal is connected to its emitter terminal, and an inverter is connected to this base terminal via a resistor 24.
IC23 and NAND gate IC22 are connected. The input terminals of the NAND gate IC 22 are both at H level (high potential state) when the timer switch 2'' is in the broken line state and the SCR 15 (described later) is OFF, and its output terminal is at L level (low potential close to OV). potential), and inverter IC2
When the output of No. 3 is inverted and becomes H level, the transistor 27 is turned on and the first relay 10 is activated. 12 is a diode connected in series to a series circuit of a resistor 13 and a capacitor 16, and 42 and 14 are resistors.

In the above SCR15, the thermostat 3 for temperature adjustment is activated once from the time the timer switch 2'' goes to the broken line state.
The structure is such that when it is turned off and then turned on again as the temperature inside the refrigerator rises, a charging current flows through the diode 18 and resistor 19 to the capacitor 20 and turns on, and due to the conduction of the SCR 15, the anode terminal side goes to L level and becomes NAND. One input of the gate IC22 is at the L level, its output is at the H level, and the output of the inverter IC23 is at the L level, so that the transistor 27 is turned off.

17 and 21 indicate resistance. Reference numeral 11 denotes a second relay operated by a delay circuit A to be described later, which operates a relay switch 11' inserted between the blower fan 9 and the door switch 8 from "open" to "closed". be. The delay circuit A is configured such that at the end of the defrosting cycle, that is, when the timer contact 2'' switches to the solid line state, when the capacitor 39 is charged with DC voltage by the diode 31 and the resistor 32, the voltage is passed through the resistor 35. The capacitor 36 is gradually charged and the charging voltage of the capacitor 36 [PUT40
(Programmable Union Transistor) anode voltage] is divided by resistors 37 and 38 (gate voltage of PUT 40)
When the voltage becomes larger, PUT 40 changes from OFF to ON, and the transistor 34 turns ON due to the cathode current of PUT 40, turning on the second relay 11.
The structure is such that In addition, 41 is a resistor inserted between the cathode terminal of PUT 40 and the base terminal of transistor 34, and 33 is the second relay 11.
26 is a diode connected in parallel to the first relay 10, and 30 is a capacitor connected in parallel to the series circuit of the first relay 10 and the transistor 27.

Here, the operation of the present invention will be explained. First, during normal cooling operation, that is, when the timer contact 2'' is in the solid line state, the timer motor 2' is energized for the time the compressor 4 is operating, and the time of energization to the compressor 4 is accumulated. The operation is the same as in FIG.

When the timer motor 2' integrates a predetermined time, the timer contact 2'' changes from a solid line to a broken line, energizing the diode 12 and applying DC voltage to the capacitor 16. At this time, the SCR 15 Since it is still OFF, both input terminals of the NAND gate IC22 are at H level, and its output is at L level - inverter IC23.
Since the output of is inverted and becomes H level, the transistor 27 is turned on and the first relay 10 is energized. This energization of the first relay 10 closes the relay switch 10' and opens the other relay switch 10''.Thus, although the defrosting timer 2 is in the defrosting mode, the first relay 10 is closed. Since the relay switch 10'' is OFF, the defrosting heater 5 and the drain heater 6 are not energized, and the compressor 4 continues to operate via the other relay switch 10'.

In other words, the operation remains completely normal. Incidentally, when the thermostat 3 is turned off, the electric charge stored in the capacitor 20 is discharged through a closed circuit on the compressor 4 side. As the temperature inside the refrigerator cools down, the thermostat 3 for temperature control is turned off, and when the temperature rises and the thermostat 3 is turned on again, a charging current flows through the diode 18 and resistor 19 to the capacitor 20, so that The SCR 15 is turned ON by the current, and the anode terminal voltage becomes L level. Therefore, NAND gate IC22
Since one input of the inverter IC23 becomes L level, its output side becomes H level, the output of inverter IC23 becomes L level, and transistor 27 is turned off. Therefore, the power to the first relay 10 is cut off, the relay switch 10' is turned OFF, and the relay switch 10'' is turned ON, so that the defrosting heater 5 and the drain heater 6 are energized, and the defrosting action is started. .In other words, Thermo 3 for temperature adjustment is not required.
Since defrosting begins when the refrigerator turns from OFF to ON (when the temperature rises), the cold air obtained by compressor 4 is sufficiently sent to each part of the refrigerator before defrosting begins. Therefore, no cold air is wasted, and since defrosting starts when the temperature inside the refrigerator rises to some extent, the defrosting heater 5 can efficiently defrost. That is, the time required for defrosting is short and the power consumption is also low.

After that, the temperature rises and the differential thermometer 7 turns off.
Then, the timer motor 2' rotates, and after about a few minutes, the timer contact 2'' changes from a broken line to a solid line, and the compressor 4 starts operating.
On the other hand, the second relay 11 is delayed by the delay circuit A and operates to close the relay switch 11' and close the energizing circuit of the blower fan 9. That is, when the capacitor 39 is charged with DC voltage by the diode 31 and the resistor 32, the capacitor 36 is gradually charged through the resistor 35. capacitor 3
When the voltage of 6 becomes larger than the voltage divided by the resistors 37 and 38, the PUT 40 changes from OFF to ON, the cathode current of the PUT 40 turns the transistor 34 ON, and the second relay 11 turns on.
When turned ON, the relay switch 11' is closed.
Generally, when the blower fan 9 starts blowing air immediately after defrosting, the hot air from the evaporator is sent to various parts of the refrigerator because the evaporator has not yet cooled down, causing the temperature inside the refrigerator to rise, albeit temporarily. Therefore, it has a negative impact on the stored food.
However, according to the present invention, by delaying the second relay 11, the start of air blowing by the blower fan 9 can be delayed and the above-mentioned drawbacks can be solved.

FIG. 3 shows another embodiment of the device of the present invention, in which only the delay circuit of the blower fan 9 is changed. Note that the control for starting defrosting will be omitted.

The embodiment shown in FIG. 3 not only delays the start of rotation of the blower fan 9 from the end of defrosting, but also turns the compressor 4 ON and OFF during normal operation (when defrosting has not started). On the other hand, the blower fan 9
This is delayed ON and OFF. This is because immediately after the compressor 4 starts operating, the temperature of the evaporator is higher than normal even during normal operation, so if the start of rotation of the blower fan 9 is delayed, cool air can be sent to each part of the refrigerator more efficiently.

43, 44, 58 are diodes, 45 is a relay that opens and closes the relay switch 45', 46 is a transistor, 47 is a NAND gate IC, 48 is an inverter IC, 49, 50, 51 is a capacitor 52, 53, 54, 55, 56 , 57, 59 are resistances. When defrosting is completed and the timer contact 2'' returns from the broken line to the solid line, the capacitor 50 is charged through the resistor 53, and the capacitor 51 is charged through the resistor 59.Normally, the capacitor 51 is charged.
Since it is set so that charging is faster, the input terminal of the NAND gate IC 47 connected to the resistor 56 becomes H level first. Approximately a few minutes after the end of defrosting, the voltage of capacitor 50 rises and resistor 57
When the input terminal of the NAND gate IC47 connected to the IC also goes to H level, the output of IC47 goes to L level and the IC
The output of transistor 48 becomes H level, and transistor 4
6 turns on, relay 45, relay switch 4
5' turns ON and the blower fan 9 starts rotating.
After thermo 3 turns off, capacitor 51
The relay 45 is
It's turned on. Next, when the thermostat 3 is turned on, the start of rotation of the blower fan 9 is delayed by the time constant of the resistor 59 and capacitor 51.

Figure 4 shows another embodiment of the device of the present invention.
This is also a modification of the delay circuit as in FIG. 3.

D ₁ to _{D 5} are diodes, ZD ₁ is a Zener diode, R ₁ to _{R 14} are resistors, C ₁ to _{C 5} are capacitors,
10 is a first relay that closes relay switch 10' when energized and opens another relay switch 10'', Q ₁ is a transistor that is energized when SCRQ ₂ is OFF, and Q ₃ is turned ON when ICQ ₄ is turned on. A transistor for energizing the second relay 11 is shown.

Now, when the timer contact 2'' of the defrosting timer 2 is in the state of the broken line, the temperature control thermostat ₃ is ON, so the capacitor C ₃ ,
Although C ₂ has been fully charged, no trigger current flows through the gate of SCRQ ₂ and SCRQ ₂ remains OFF, transistor Q ₁ is turned ON and first relay 10 is energized. Therefore, the defrosting cycle is not entered and steady operation is maintained by closing the relay switch 10'. Then, the thermometer 3 above turned off once.
When it is turned ON again after the temperature has decreased (when the temperature of the freezer becomes high), the gate current of SCRQ ₂ flows due to the charging current to capacitor C ₂ , and SCRQ ₂
is turned on, transistor _Q1 is turned off, first relay 10 is turned off, and the defrosting heater 5 and drain heater 6 are energized.

The completion of defrosting is the same as shown in Figure 2, and the defrost
When the timer motor 2' is opened, the timer motor 2' is energized, and after a predetermined period of time has elapsed, the timer contact 2'' is switched to a solid line state.Then, the compressor 4 is operated immediately, but the compressor 4 is not operated until the charging of the capacitor _C5 is completed. Since the second relay 11 is OFF, the blower fan 9 is stopped, and when the capacitor _C5 reaches the charging voltage after a certain period of time, the transistor _Q3 becomes conductive and the second relay 11 is energized, causing the blower fan 9 to rotate. is started.

As described above, in this invention, the defrosting start timing is made to coincide with the change from OFF to ON of the temperature control thermo, so there is no need to heat the evaporator with the defrost heater after cooling the evaporator as in the past. Not only can you eliminate rationality, but the time when the defrosting heater is actually energized is determined by the temperature of the thermostat mentioned above.
Since it is switched from OFF to ON, that is, when the temperature inside the refrigerator reaches a relatively high temperature, the time for which electricity is applied to the defrosting heater is short, and the electricity bill is reduced, which is a remarkable effect. .

[Brief explanation of the drawing]

Fig. 1 is an electrical circuit diagram of a conventional defrosting device, Fig. 2 is an electrical circuit diagram of the defrosting device of the present invention, and Figs. 3 and 4 are electrical circuit diagrams of other embodiments of the defrosting device of the present invention. shows. 2: Defrost timer, 2': Timer motor, 2'': Timer contact, 3: Temperature control thermostat,
4: Compressor, 5: Defrost heater.

Claims (1)

[Scope of utility model registration request] A timer means for accumulating the ON time of the compressor, a temperature adjustment means for turning the compressor ON and OFF, a defrosting means for defrosting, and a detection means for detecting that the temperature adjustment means has changed from OFF to ON. and when the timer means integrates the time required for entering the defrosting cycle, the detecting means first detects a change in the temperature adjusting means from OFF to ON, and then energizes the defrosting means. Defrost control device is a feature.