JPS6325496Y2 - - Google Patents

Description

[Detailed explanation of the idea]

The present invention relates to a device for controlling the cooling of a cooling device that supplies compressed gas from one compressor to a plurality of evaporators to cool a plurality of loads, respectively. Generally, there is a cooling system as shown in FIG. 1, in which a plurality of evaporators provided in a plurality of refrigerators are operated in parallel by one compressor. In Figure 1, 1,
Reference numerals 2 and 3 indicate evaporators provided in different freezing or refrigerating cases. Compressor 5
The high-temperature, high-pressure gaseous refrigerant discharged from the refrigerant is led to the condenser 6 and liquefied. The liquid refrigerant that has passed through the condenser 6 passes through a liquid pipe 8 and is branched into three electromagnetic valves SV ₁ , SV 2 , and SV ₃ provided corresponding to the evaporators 1 , ₂ , and 3 . Each refrigerant that has passed through the three electromagnetic valves SV ₁ to _{SV 3} is depressurized by the expansion valve 7, and then guided to the corresponding evaporator 1, 2, and 3, respectively. In the evaporators 1, 2, and 3, the refrigerant evaporates and removes heat from the surroundings, thereby cooling the interior of each case. The refrigerants that have passed through the evaporators 1, 2, and 3 are led to the suction side of the compressor 5 through a suction pipe 9 in common. Solenoid valve SV ₁ ,
When SV ₂ and SV ₃ are energized, the valves open to allow refrigerant to pass through. As a conventional device for controlling the electromagnetic valves SV ₁ , SV ₂ , and SV ₃ in a cooling device capable of forming such a refrigerant circulation route, there is a device as shown in FIG. 2.
In other words, a thermostat is installed inside each show case, and the contacts of the thermostat are
The following temperature control is performed using TH ₁ to _{TH 3} . When the interior of a given case is sufficiently cooled, the corresponding thermostat contact opens, de-energizing the corresponding solenoid valve, stopping the flow of refrigerant into the evaporator, and raising the temperature. When the temperature rises enough,
The thermostat contacts close, allowing refrigerant to flow through the corresponding solenoid valve and cooling again. In such a control circuit, the three solenoid valves SV ₁ to _{SV 3} have no relation to each other, and each has a contact point of the corresponding thermostat.
Controlled independently by TH ₁ to TE ₃ . Therefore,
The load on the cooling device is distributed, resulting in low load and low efficiency operation. Therefore, the present applicant et al.
Preventing low efficiency operation, concentrating load,
In order to achieve high-load, high-efficiency operation and save energy, we have already proposed a control device that synchronizes the opening and closing timing of each of the above-mentioned solenoid valves as much as possible. For example, there is a control device described in Japanese Patent Application No. 132997 of 1980. The control device described in Japanese Patent Application No. 132997 of 1988 is a control device for a cooling device in which compressed gas is supplied from one compressor to a plurality of evaporators to cool a plurality of loads respectively. , a plurality of electromagnetic valves each inserted and connected to the input side of the plurality of evaporators, and each of the plurality of loads is provided with a first state ( a plurality of thermostats that are in a second state (on) when the temperature rises above the upper limit of the predetermined temperature; and one of the thermostats is in the first state. (off), and after a certain period of time _Ts , all the solenoid valves are closed and the compressor is stopped, and after the compressor is stopped, all the thermostats are turned off. The compressor is restarted when the second state (on) is reached. However, this control device has a drawback in that even if the timer is used, it can only perform synchronous control in which each electromagnetic valve is synchronized as much as possible. The aim of the invention is to eliminate the above-mentioned drawbacks. The present invention is provided with a switch for switching the control mode, and when the switch is set to the first control mode, the original synchronous control using the above-mentioned timer is performed, and the switch is set to the second control mode. When the synchronous control is set, the synchronous control is canceled and the corresponding plurality of electromagnetic valves are controlled only by the plurality of thermostats, as shown in FIG. 2. Embodiments of the present invention will be described below with reference to the drawings. The control device according to the embodiment of the present invention shown in FIGS.
This controls the opening and closing of the valves SV ₁ , SV ₂ , and SV ₃ .
In the figure, TH ₁ , TH ₂ , and TH ₃ are the contacts of a thermostat installed in a show case equipped with evaporators 1, 2, and 3, respectively. The thermostat opens the contact when the temperature inside the refrigerator falls below a predetermined lower limit (thermostat off value), and conversely, when the temperature inside the refrigerator rises above the upper limit of the predetermined temperature (thermostat on value), It closes the contact. 10 is a power supply for the control circuit, 11 is a power supply for driving the compressor 5, and 12 is a constant voltage power supply circuit. Also, 100 is a switch for changing the control mode, when set to _M1 , the original synchronous control is performed, and when set to _M2 , the above synchronous control is canceled and the switch is changed to the one shown in Fig. 2. Conventional control can be performed. In addition, 13 is the thermostat contact TH ₁ ~
This is the input circuit in the TH ₃ state. This input circuit 1
3, when thermostat contact TH ₁ is on,
A high level signal "H" is applied to the signal line 14-1, and a low level signal "L" is applied to the signal line 15-1. Conversely, when thermostat contact TH ₁ is off,
"L" is applied to the signal line 14-1, and "H" is applied to the signal line 15-1. Similarly, when the thermostat contact TH ₂ or TH ₃ is on, the input circuit 13
Apply "H" to the signal line 14-2 or 14-3 and "L" to the signal line 15-2 or 15-3. Conversely, when the thermostat contact TH ₂ or TH ₃ is off, the signal line 14 -2 or 14-3 "L", signal line 15-2 or 15-3 "H"
give. The logic circuit 18 includes signal lines 15-1, 15-2,
When any of 15-3 becomes “H”, the signal line 19
is set to "H", and the signal lines 15-1, 15-2,
When all of the signals 15-3 become "H", the signal line 20 is set to "H". That is, an OR output is obtained on the signal line 19, and an AND output is obtained on the signal line 20. Therefore, when any of the thermostat contacts TH ₁ , TH ₂ , TH ₃ is turned off, the signal line 19 becomes "H", and when all the thermostat contacts TH ₁ , TH ₂ , TH ₃ are turned off, the signal line 20 becomes "H". H”. The logic circuit 21 includes signal lines 14-1, 14-2,
14-3 are all "H" and the compressor stop signal line 22 is "H", when the signal line 23 is set to "H", in other words, an AND output is obtained on the signal line 23. The stop signal is a signal that becomes "H" when the compressor 5 is stopped. Therefore, the compressor 5
When the thermostat contact TH ₁ is stopped,
When both TH ₂ and TH ₃ are turned on, the signal line 23 becomes "H". The logic circuit 28 is a set-reset flip-flop (SRFF), operates according to the truth table below, and sets the Q output signal 29 to "L" when the power is turned on (ie, in the initial state).

[Table] The logic circuit 30 is a timer, and while the signal line 29 is “L”, the signal line 31 is set to “L”, and the signal line 29 is set to “L”.
When becomes “H”, the signal line 31 after a certain period of time T _S
is set to “H”. The logic circuit 32 is a set-reset flip-flop (SRFF), which operates according to the truth table below, and outputs the above-mentioned compressor stop signal line 22, which is the Q output, when the power is turned on (in other words, in the initial state). I set it to "L".

[Table] The logic circuit 33 is a driver with an inverter function, and when the compressor stop signal line 22 becomes "H", it operates the relay RL ₀ and stops the power supply to the compressor 5 through its contact rl ₀ . do. The driver 34 has the compressor stop signal 22 “L”
When the output signals 35-1, 35-2, 35-3 are set to "L", and when the compressor stop signal 22 is "H", the output signals 35-1, 35-2, 35-3 are set to "H". This is a circuit that does this. Tr _1-1 , Tr _1-2 , Tr _1-3 , Tr _2-1 ,
Tr _2-2 and Tr _2-3 are transistors. The driver 34 outputs signals 35-1, 35-2, 35-3
When outputting “L” as “L”, relay RL ₁ ,
RL ₂ and RL ₃ become operational. At this time,
Relays RL ₁ , RL ₂ , RL ₃ operate when the corresponding thermostat contacts TH ₁ , TH ₂ , TH ₃ are on,
The self-contacts rl ₁ , rl ₂ , rl ₃ are turned on to allow the corresponding solenoid valves SV ₁ , SV ₂ , SV ₃ to be energized. When the compressor stop signal 22 is “H”, the relays RL ₁ , RL ₂ ,
RL ₃ is inactive and solenoid valves SV ₁ , SV ₂ , SV ₃ are not energized. The operation of this control circuit will be explained below. First, switch 100 is in its original synchronous control mode.
The case where it is set to _M1 will be explained. When all the cases are cooled and one of the thermostat contacts TH ₁ to _{TH 3} is turned off, the OR output 19 of the logic circuit 18 becomes "H", the flip-flop 28 is set, and the timer 30 starts counting. Start. Then, when the time T _S set in the timer 30 has elapsed,
The output 31 of the timer 30 becomes "H", the flip-flop 32 is set, and the compressor stop signal 22, which is its Q output, becomes "H". Then, the driver 33 operates the relay RL ₀ , so the power to the compressor 5 is cut off. On the other hand, driver 34
makes relays RL ₁ to RL ₃ inactive, so
Power to the solenoid valves SV ₁ to SV ₃ is cut off. As a result, cooling of the case that has not yet been cooled to the thermostat off value is also stopped. If all the thermostat contacts TH ₁ to _{TH 3} turn off before the timer 30 counts the T _S time, the AND output 20 of the logic circuit 18 becomes "H" and the flip-flop 32 is set. Therefore, when all of the thermostats TH ₁ to _{TH 3} are turned off, the state can be the same as when the timer 30 has counted the T _S time. In this way, all the cases have almost the same cooling stop timing. When the internal temperature of the show case rises and all the thermostat contacts _TH1 to _TH3 are turned on, the output 23 of the AND circuit 21 becomes "H".
As a result, the flip-flops 28 and 32 are reset, the timer 30 is returned to its initial state, and the compressor stop signal 22 is set to "L". Then, the driver 33 makes the relay RL ₀ inactive, and the driver 34 makes the relays RL ₁ to RL ₃ in the operating state, so the compressor 5 and all the solenoid valves SV ₁
~Electrification to SV ₃ begins. In this way, all the cases have the same cooling start time. Next, the switch 100 enters the synchronous control release mode.
The case where it is set to _M2 will be explained. In this simultaneous control release mode, the power supply V _cc1 is not supplied to the control circuit of FIG. 4. In this state, relay RL ₁ is inactive and compressor 5 is energized. On the other hand, the compressor stop signal 22 is "L" when the power supply V _cc1 is not supplied, and therefore the transistors Tr 1-1 and Tr _1-1 in the driver 34
By turning on Tr _1-2 and Tr _1-3 , signal 3
5-1, 35-2, and 35-3 are "L". Therefore, relays RL ₁ , RL ₂ , and RL ₃ operate/deactivate depending on whether the thermostat is on or off, and the solenoid valve
Controls the energization status of SV ₁ , SV ₂ , and SV ₃ . That is, just as in FIG. 2, only a plurality of thermostats control a plurality of corresponding solenoid valves. Note that once the switch 100 enters the control release mode _M2 , it is only necessary to set the signals 35-1, 35-2, and 35-3 to "L", and various changes may be made in this regard. FIG. 5 shows another embodiment of the present invention. In FIG. 5, the output 331 of the driver 33 in FIG.
is added to one end of relays RL ₁ , RL ₂ , RL ₃ .
That is, the driver 34 in FIG. 3 is also used as the driver 33 in FIG. 4. This fifth
In the circuit shown, when the switch 100 is set to the synchronous control release mode _M2 , the power supply _Vcc1 is connected to the relay
Not only RL ₀ but also RL ₁ , RL ₂ , and RL ₃ are not supplied,
Relays RL ₀ to RL ₃ are all inactive. Therefore, the compressor 5 is in an energized state, and the solenoid valve
SV ₁ to _{SV 3} are controlled to be energized or de-energized depending on whether the thermostat contacts TH ₁ to _{TH 3} are turned on or off. When switch 100 is set to synchronous control mode _M1 , the operation is essentially the same as in FIGS. 3 and 4. Note that the same operation can be performed even if the switch 100 is moved to the position shown in FIG. According to the present invention, it is possible to compare the operations in the synchronous control mode and the synchronous control release mode, and the synchronous control release mode allows easy inspection and inspection of the elements of each part. Extremely large.

[Brief explanation of the drawing]

Figure 1 is a refrigerant circulation system diagram of a cooling system in which multiple evaporators installed in multiple refrigerators are operated in parallel with one compressor, Figure 2 is a circuit diagram of a conventional control system, Figure 3 and FIG. 4 is a circuit diagram of a control device according to one embodiment of the present invention, and FIG. 5 is a circuit diagram of a control device according to another embodiment of the present invention. 1, 2, 3...Evaporator, 5...Compressor, 6...
Condenser, 7... Expansion valve, SV ₁ to SV ₃ ... Solenoid valve,
TH ₁ ~ _{TH 3} ...Thermostat contact, RL ₀ ~ _{RL 3}
... Relay, rl ₀ to rl ₃ ... Contact of relays RL ₀ to RL ₃ , 30... Timer, 100... Switch for switching control mode.

Claims (1)

[Claims for Utility Model Registration] A system installed in each of a plurality of loads, which enters the first state when the temperature of each load falls below the lower limit of a predetermined temperature, and conversely rises above the upper limit of the predetermined temperature. A plurality of electromagnetic valves that adjust the supply of compressed gas from a compressor in a cooling device to a plurality of evaporators for cooling the plurality of loads based on a state of each of the plurality of thermostats that is a second state. In the control device that opens and closes the thermostats and controls the temperature of the plurality of loads, the thermostat starts working when any one of the plurality of thermostats reaches the first state, and after a certain period of time, all the thermostats start working. The solenoid valve is closed and the compressor is stopped, and furthermore, after the compressor is stopped, when all the thermostats of the plurality of thermostats are in the second state, all the solenoid valves are closed. and a first control circuit that restarts the compressor; and a first control circuit that causes opening and closing of each of the solenoid valves to correspond to the first and second states of each of the plurality of thermostats, and controls the compression to the plurality of evaporators. A control device comprising: a second control circuit that individually controls gas supply; and a selection switch that selectively operates one of the first and second control circuits.