JPS6015082Y2 - Refrigeration equipment - Google Patents

Description

[Detailed description of the invention] The present invention relates to an improvement of a refrigeration system, and a single low pressure switch has an abnormal low pressure protection function and a pump down stop function, and also has a function to prevent automatic recovery in the event of an abnormal stop. It is characterized by the fact that

Conventional refrigeration equipment is known to have an abnormally low pressure protection function using a low pressure switch, but not to have a pump down stop function.

However, in such conventional refrigeration equipment, especially in separate type refrigeration equipment, it is difficult for oil to return to the compressor when it is stopped.
This not only has the drawback of causing compressor seizure, but also poses a risk of liquid backlash when the compressor is restarted.

In addition, when the low pressure is abnormally low, such as when there is a shortage of refrigerant, the low pressure switch is activated and the compressor operation is automatically stopped. When the high and low pressures are balanced, the low pressure switch automatically returns and restarts the compressor. It had the disadvantage of repeatedly starting and stopping as it started driving.

The present invention was developed in view of the above circumstances, and allows the refrigeration system to be automatically pumped down and stopped when normal operation is stopped or stopped by a thermoswitch for detecting room temperature, and the low pressure side refrigerant circuit is In the event of abnormally low pressure, such as when there is a shortage of refrigerant, the system can be forcibly stopped, and the automatic restart of the refrigeration system during such an abnormal stop can be prevented. A refrigeration system that can be operated by operation and can prevent repeated starts and stops; in other words, a single low pressure switch has an abnormal low pressure protection function and a pump down stop function, and also functions to prevent the abnormal stop. It is an object of the present invention to provide a refrigeration system that can prevent automatic return that sometimes occurs.

The technical means of the present invention to solve the above technical problem is to connect an auxiliary relay, a liquid receiver, and an expansion mechanism to a series circuit of a stop switch and a run switch connected to a power source via a thermoswitch for detecting room temperature. A parallel circuit with the electromagnetic coil of the electromagnetic valve interposed in the refrigerant circuit between the valves is connected, and the low pressure switch connected to the power source opens at a predetermined pressure or lower, and the thermoswitch opens for a predetermined period of time in response to a signal from the thermoswitch. An operation command relay for issuing an operation command signal to the compressor is connected in series to the parallel circuit with the contact between the two, and a protection circuit connected to the power source has the normally closed contact of the auxiliary relay and the operation A parallel circuit with the normally open contact of the command relay,
The abnormality detection relay, which becomes de-energized in the event of an abnormality, is connected through a circuit that is connected in series with a contact that opens in response to a command from the run switch and closes in response to a command from the stop switch, and a parallel circuit of the normally open contact of the abnormality detection relay. , the normally open contact of the abnormality sensing relay is interposed in a parallel circuit of the low pressure switch and the contact, and a series circuit with the operation command relay.

Hereinafter, one embodiment of the present invention will be described in detail based on the drawings.

Fig. 1 is a refrigerant circuit diagram of a separate type refrigeration system according to the present invention, in which 1 is an outdoor unit, 2 is an indoor unit, and the outdoor unit 1 has a built-in electric motor 3 (see Fig. 2). A compressor 4, an accumulator 5, a condenser 6,
The indoor unit 2 is also provided with an expansion mechanism 8 and an evaporator 9, which are connected by refrigerant piping to form a circulating refrigeration cycle.

Further, a solenoid valve 12 equipped with an electromagnetic coil 11 (see FIG. 2) is provided in the refrigerant circuit between the liquid receiver 7 and the expansion mechanism 8.
are intervening.

Further, one low pressure switch 20 having a built-in low pressure switch 19 (see FIG. 2) is connected to the suction chamber of the compressor 4.

Further, a fan motor 13.1 is installed near the condenser 6.
Condenser fans 15 and 16 each having a switch evaporator fan 17 are provided.

Next, the configuration of an electric circuit whose loads include the compressor 4 and each of the fan motors 13, 14, etc. will be described in detail with reference to FIG.

In the figure, 21, 22, 23 are three-phase AC power input terminals, 2
Reference numeral 4 denotes an abnormality sensing relay having three normally open relay contacts 25, 26 and 27, and L/-24 is de-energized in the event of an abnormality.

Reference numeral 28 denotes a relay for forming a self-holding circuit during operation, and this relay 28 includes one normally closed relay contact 29 and one normally open relay contact 30.

Further, 31 is a relay having a normally open relay contact 32;
is an auxiliary relay, and this relay 33 includes one normally closed relay contact 34 and one normally open relay contact 35.

Reference numeral 36 denotes an operation command relay, and this relay 36 is equipped with two normally open relay contacts 37 and 38, and when the relay 36 is energized, the compressor 4 and the condenser fan 15 and 16 are
This is to issue driving command signals to the

39 is an electromagnetic switch for driving one fan motor 13, and this electromagnetic switch 39 has four normally open contacts 40,
41, 42, and 43.

Moreover, 44 is an electromagnetic switch for driving the other fan motor 14, and this electromagnetic switch 44 is also provided with four normally open contacts 45, 46, 47, and 48.

49 is a timer having a normally closed time contact 50, and this timer 49 is used to prevent the low pressure switch 19 from malfunctioning when the pressure in the low pressure side refrigerant circuit suddenly drops when the refrigeration circuit starts operating. Then, the short circuit time of the low pressure switch 19 by the time limit contact 50 of the timer 49 is 3.
It is set to ~5 minutes.

51 is an electromagnetic switch for driving the compressor; this electromagnetic switch 5
1 is equipped with three constant contacts 52, 53, and 54.

Therefore, each of the three-phase AC power input terminals 21°22.2
3 is connected to the compressor motor 3 through the contacts 52, 53, 54 of the electromagnetic switch 51, and the contacts 40, 53 of the electromagnetic switch 39 are connected to the
One fan motor 13 is connected through contacts 41 and 42, and the other fan motor 14 is connected through contacts 45, 46, and 47 of an electromagnetic switch 44, respectively.

However, an overcurrent relay 56 having an overcurrent switch 55 is interposed between the contacts 52 and 54 and the compressor motor 3.

In addition, the power supply line 57 is connected to the power input terminals 21 and 22.
．． 58 are connected separately, and a protection circuit 61 consisting of a thermoswitch 59 for the compressor, the overcurrent switch 55, and a high pressure switch 60 is connected between these lines 57 and 58.
, the relay contacts 29 and 34 are connected in series with the abnormality sensing relay 24, and the relay contact 29 is connected to the normally open relay contact 25 for self-maintenance of the abnormality sensing relay 24, and the relay contact 34 The normally open relay contacts 37 of the operation command relay 36 are connected in parallel to each other.

Furthermore, a series circuit of a stop switch 62, an operation switch 63, and a relay 28 is connected between the power lines 57 and 58, and a relay contact 30 for self-holding of operation is connected in parallel with the operation switch 63. , A series circuit of a relay contact 26 and a relay 31 is connected in parallel to the relay 28.

Furthermore, a series circuit consisting of a relay contact 32, a thermoswitch 64 for detecting room temperature, and the electromagnetic coil 11 is connected between each of the switches 62 and 63 and the power line 58. An auxiliary relay 33 is connected in parallel with.

Here, the room temperature detection thermoswitch 64 detects the indoor temperature and switches from the open side to the open side when the indoor temperature rises above a preset value.

Also, a relay contact 27 is connected between the power lines 57 and 58.
A series circuit of the low pressure switch 19 and the operation command relay 36 is connected, and a normally closed time contact 50 of the timer 49 is connected in parallel with the low pressure switch 19 to create a time short circuit for the low pressure switch 19. It consists of

A line 65 is connected to the common terminal of the low pressure switch 19.
A series circuit of a relay contact 35 and an electromagnetic switch 44 for driving the fan motor is connected between this line 65 and the power supply line 58, and each relay contact 38, 43 is connected to the relay contact 35. series circuits are connected in parallel, and another electromagnetic switch 39 for driving the fan motor is connected in parallel with the electromagnetic switch 44.

In addition, a series circuit of the contact 48 and the electromagnetic switch 51 for driving the compressor is connected between the lines 65 and 58, and
The timer 49 is connected to the electromagnetic switch 51 in parallel.

In addition, the above-mentioned stop switch 62 and operation switch 63
is installed on a central control panel in a central control room that is remote from the installation location of the indoor unit 2, and each of the relays 24, 2
8, 31, 33, 36, and each electromagnetic switch 39, 44
．． It goes without saying that each pilot lamp may be connected in parallel with 51, and a total of eight pilot lamps may be provided in the central control panel.

Next, the operation of the above configuration will be explained.

First, the normal operation of cooling operation will be described.

Now, when the operation switch 63 is turned on, each switch 62
．． Power is applied to relay 28 via 63, energizing it and switching its relay contacts 29,30.

The relay 2 is turned on by turning on the one relay contact 30.
A self-holding circuit for 8 is formed.

Further, although the other relay contact 29 of the relay 28 is turned off, the abnormality detection relay 24 is already energized before the operation switch 63 is turned on, and the "self-holding circuit" is activated by turning on the relay contact 25. As a result, the abnormality sensing relay 24 remains energized.

As the abnormality detection relay 24 continues to be energized, its relay contacts 26 and 27 have already been turned on, so at the same time as the operation switch 63 is turned on, the relay 31 is energized and the relay contact 32 of the relay 31 is turned on. .

Further, since the thermo switch 64 for detecting the room temperature detects the room temperature and has already switched from the open side to the open side, after the operation switch 63 is turned on, each element 57, 62
, 32, and 64 in this order, power is applied to the auxiliary relay 33 and the electromagnetic coil 11 of the electromagnetic valve 12, and the auxiliary relay 33 is excited, and the electromagnetic valve 12 is opened.

When the auxiliary relay 33 is energized, its relay contact 3
4.35 is switched and one contact 34 is turned off, but a normally open relay contact of an operation command relay 36 is connected in parallel with this relay contact 34, and the operation command relay 36 is connected to the operation switch 63. An abnormality was detected before the power was turned on, and at the same time as the energization of 24, it was already energized via each element 27.50 or 27.19, and its relay contact 37.38 was turned on. Since it forms a self-holding circuit for the abnormality detection relay 24, the abnormality detection relay 24 continues to be energized even after the relay contact 34 is turned off.

When the auxiliary relay 33 is energized and its relay contact 35 is turned on, power is applied to each fan motor drive electromagnetic switch 39.44 through the contact 35, and each of these electromagnetic switches 39.44 is turned on. are energized together, turning on their respective contacts 43,48.

When the contact 48 is turned on, power is applied to both the timer 49 and the electromagnetic switch 51 for driving the compressor through the contact 48, and both the timer 49 and the electromagnetic switch 51 are excited.

At the same time when the electromagnetic switches 39, 44 for driving each fan motor are excited, the contacts 40, 41, 42 and 45° 46, 47 of the electromagnetic switches 39, 44 are turned on, and each fan is turned on. Power is applied to the motors 13 and 14, and the condenser fans 15 and 16 rotate.

Moreover, at the same time that the electromagnetic switch 51 for driving the compressor is excited, each contact 52, 53, 54 of the electromagnetic switch 51 is excited.
is turned on, power is applied to the compressor motor 3, and the compressor 4 is started.

In this way, when the compressor 4 is driven following the opening of the electromagnetic valve 12, the refrigerated gas compressed by the compressor 4 to a high temperature and high pressure is transferred to the condenser 4 as shown by the solid line arrow in FIG. The refrigerant enters the air and exchanges heat with the outside air, becoming a high-pressure liquid refrigerant.

The liquid refrigerant liquefied in the condenser 6 passes through the liquid receiver 7 and the opened electromagnetic valve 12 to reach the expansion mechanism 8, where the liquid refrigerant is throttled and expanded to a low pressure and enters the evaporator 9 to be discharged from the outside. It removes heat and is vaporized to become a gas refrigerant, which is then sucked into the compressor 4 again via the accumulator 5.

Here, when the refrigeration system starts operating, the pressure in the low-pressure side refrigerant circuit may drop suddenly, and this drop in low-pressure pressure causes the low-pressure pressure switch 19 to change from the normally closed side, which is the energized side, to the normally closed side, which is the non-energized side. Although it switches to the open side,
Since the normally closed time contact 50 of the timer 49 is connected in parallel to this low pressure switch 19, even if the low pressure switch 19 is turned off, the operation command relay 36 is not activated via each element 27.50. Since power is continuously applied, the refrigeration system is not stopped unnecessarily due to a drop in low pressure at the start of operation, and the cooling operation can be continued normally.

Note that the normally closed time contact 50 is activated after the timer 49 is energized.
When the short-circuit time of 3 to 5 minutes preset by the timer 49 has elapsed, the circuit is turned off due to time-up, and the pressure in the low pressure side refrigerant circuit returns to normal pressure within this 3 to 5 minutes.

Next, the action related to stopping the pump down will be explained.

Now, when the stop switch 62 is turned off when the operation is stopped, the relay 28.31, the auxiliary relay 33, and the electromagnetic coil 11 of the electromagnetic valve 12 are cut off, and each of these elements 28. 31. 33.11 is de-energized.

By de-energizing the relay 28, its relay contact 30
is turned off to release the self-holding of the relay 28, and the other IJ L/- contact 29 of the relay 28 returns to its original state (normally closed state).

Further, by de-energizing the relay 31, the relay contact 32 is turned off.

Furthermore, by de-energizing the auxiliary relay 33, the relay contact 34 of the relay 33 returns to its original state (normally closed state), and the other relay contact 3 of the relay 33 returns to its original state (normally closed state).
5 is turned off.

Furthermore, by de-energizing the electromagnetic coil 11, the electromagnetic valve 12 in the refrigerant pipe is closed, and communication between the liquid pipe passages is cut off.

At this time, each element 59.5 is connected to the abnormality detection relay 24.
Since power is applied through 5.60, 25, and 37, the relay 24 continues to be energized, and since the relay contact 27 is turned on, the operation command relay 36 also continues to be energized. Since the relay contact 38 of the relay 36 remains on, even if the relay contact 35 of the relay 33 is turned off, the relay contact 38 and the electromagnetic switch 39,44 for driving the fan motor are not connected to each other. Since power is continuously applied through the contact 43 that is already turned on, and the contact 48 of the electromagnetic switch 14 remains on,
The electromagnetic switch 51 for driving the compressor remains excited.

For this reason, the compressor electric motor 3, the fan motor 13.
14 as well as condenser fans 15, 16 and compressor 4 continue to operate.

Therefore, the pump-down operation is started from the time when the communication of the liquid piping passage is cut off by closing the electromagnetic valve 12.

In this way, when the pump-down operation is started, the refrigerant in the refrigerant system is drawn to the compressor and then to the condenser 6.
and is stored in the liquid receiver 7.

As a result, the pressure in the low-pressure refrigerant circuit 18 gradually decreases, and when the pressure in the low-pressure refrigerant circuit 18, that is, the pressure in the suction chamber of the compressor 4 becomes lower than the value preset by the low-pressure switch 20, the low pressure Since the pressure switch 19 switches from the normally closed side to the normally open side and cuts off the energization path to the operation command relay 36, the excitation of the relay 36 is canceled and the relay contact 38 is turned off, and the above-mentioned The electromagnetic switches 39 and 44 for driving each fan motor are de-energized, and the contacts 48 of the electromagnetic switches 44 are turned off due to the de-energization of the electromagnetic switches 44, and the electromagnetic switches 39 and 44 for driving the timer 49 and the compressor are turned off. The power to the device 51 is removed.

In this way, when the electromagnetic switches 39 and 44 for driving the fan motor and the electromagnetic switches 51 for driving the compressor are de-energized, the fan motor 13 and 14 and the compressor motor 3 are no longer energized. Since it is shut off, the condenser fans 15 and 16 and the compressor 4 are stopped to complete the pump down.

When the pump down is stopped, the auxiliary relay 33 is deenergized and its relay contact 34 returns to its original normally open state, so the relay contact 37 of the operation command relay 36 is turned off by the operation of the low pressure switch 19. However, each element 59, 55, 60, 29 is connected to the abnormality detection relay 24.
．． Since power is applied through the relay 34, the abnormality sensing relay 24 is continuously energized.

Therefore, when the operation switch 63 is manually turned on, operation can be started again.

The above is an explanation of the operation of the pump down stop based on the manual off operation of the stop switch 62, but the operation occurs when the indoor temperature is cooled to the set value by air conditioning operation and the thermo switch 64 for room temperature detection is switched to the open side. The above-mentioned action also exists in the same manner as S.

That is, when the thermo switch 64 detects the room temperature and switches to the open side, the auxiliary relay 33 and the electromagnetic coil 11 of the electromagnetic valve 12 are de-energized, the electromagnetic valve 12 is closed, and the liquid piping passage is closed. Since the communication is cut off, pump-down operation is started in the same manner as described above, and due to lack of gas in the low-pressure refrigerant circuit 18 due to this operation, the low-pressure pressure switch 19
is activated and the pump down is completed in the same manner as described above, and operation can be restarted when the thermoswitch 64 detects a rise in room temperature and switches to the closing side. be.

Next, a description will be given of the operation of the low pressure switch 19 to automatically stop the operation of the compressor 4 when the pressure is abnormally low due to lack of gas or the like.

During the normal cooling operation, both the auxiliary relay 33 and the operation command relay 36 are energized, the normally open relay contact 34 of the auxiliary relay 33 is off, and the normally open relay contact 37 of the operation command relay 36 is energized. It's on.

Here, the pressure of the low pressure refrigerant circuit 18 decreases abnormally,
When the pressure falls below the preset value with the low pressure switch 20, the low pressure switch 19 switches from the normally closed side (energized side) to the normally open side (non-energized side), and the operation command relay 3
6 is cut off, and the excitation of the relay 36 is released.

When the drive command relay 36 is de-energized, its relay contact 37 is turned off.

In other words, the 2
The parallel circuit consisting of the two relay contacts 34 and 37 cuts off the power to the abnormality sensing relay 24 because these contacts 34 and 37 are both turned off.

When the power to this abnormality detection relay 24 is cut off and the excitation of the relay 24 is released, each relay contact 25, 26, 2 of the relay 24 including the self-holding relay contact 25
7 is switched from on to off, and the relay contact 27
In order to cut off power to the electric circuit thereafter, following the stop of the fan motors 13 and 14 and the compressor motor 3,
The condenser fans 15 and 16 and the compressor 4 are stopped, and the operation of the system can be forcibly stopped.

Moreover, it is possible to prevent automatic recovery at the time of such an abnormal stop.

That is, when the abnormality detection relay 24 is de-energized, its relay contact 26 is turned off, cutting off the power supply to the relay 31, and turning off the relay contact 32 of the relay 31.
By turning off this relay contact 32, the auxiliary relay 33
and the relay 3 cuts off the energization to the electromagnetic coil 11.
Although the relay contacts 34 of No. 3 return to the normally closed state, the parallel circuit consisting of the two relay contacts 25 and 26 interposed in the energizing path to the abnormality sensing relay 24 is connected to each of these two relay contacts 25 and 29. Since both are off, unless the stop switch 62 is turned off to cut off the power to the relay 28 and return the relay contact 29 of the relay 28 to its original normally closed state, the abnormality detection relay Since it is impossible to energize 24, automatic recovery at the time of the abnormal stop can be prevented.

Therefore, users can confirm abnormal stoppages,
After repairing the defective parts through maintenance and inspection, turning off the stop switch 62 and then turning on the operation switch 63 allows operation to resume, which prevents the compressor from starting and stopping as in conventional systems. It is possible to prevent the repetition of the above.

Note that during the normal cooling operation, the overcurrent relay 5
6. Even if any one of the compressor thermoswitch 59 and the high pressure switch 60 is activated, the power to the abnormality detection relay 24 is cut off, and the operation of the refrigeration system is forcibly stopped. Of course, it is possible to do so.

In addition, as noted before entering into the explanation of the operation, the stop switch 62 and the operation switch 63 are provided on a central control panel in a central control room that is remote from the installation location of the indoor unit 2, and each of the relays 24.2B, 31,33.3
6 and each electromagnetic switch 39, 44.51 in parallel, and a total of eight pilot lamps are provided in the central control panel, the operating state and various stop states of the refrigeration equipment can be centrally controlled. The low pressure switch 19 can be accurately grasped in the chamber.
It goes without saying that by operating this function, it is possible to more clearly confirm an abnormal stop of the device and a pump-down stop.

As described in detail above, the present invention connects the auxiliary relay 33, the liquid receiver 7, and the expansion mechanism 8 to the series circuit of the stop switch 62 and the operation switch 63 connected to the power source through the thermoswitch 64 for detecting room temperature. A parallel circuit with the electromagnetic coil 11 of the electromagnetic valve 12 interposed in the refrigerant circuit 10 between the two is connected, and signals from the low pressure switch 19 and thermoswitch 64, which are connected to the power source and open below a predetermined pressure, are connected. An operation command relay 36 for issuing an operation command signal to the compressor 4 is connected in series to the parallel circuit with the contact 50 which is opened for a predetermined time and remains open after that, and the protection circuit 61 connected to the power source is further connected to the A parallel circuit of the normally closed contact 34 of the auxiliary relay 33 and the normally open contact 37 of the operation command relay 36, a contact 29 that opens in response to a command from the operation switch 63 and closes in response to a command from the stop switch 62, and the abnormality detection relay 24. An abnormality detection relay 24 that becomes de-energized in the event of an abnormality through a circuit in which a normally open contact 25 and a parallel circuit are connected in series.
and the normally open contact 27 of the abnormality detection relay 24 is interposed in the parallel circuit of the low pressure switch 19 and the contact 50 and the series circuit of the operation command relay 36, so that normal operation can be stopped. When stopped by the thermo switch 64 for detecting room temperature and room temperature, the device can be automatically pumped down and stopped, and the device can be forcibly stopped in the event of abnormally low pressure such as when there is a shortage of refrigerant in the low pressure side refrigerant circuit. can.

Furthermore, since it is possible to prevent the refrigeration system from restarting due to automatic recovery in the event of an abnormal stop, it is possible to clearly distinguish whether the system is stopped due to pump down or due to abnormal operation. In the event of an abnormal stop, the defective parts can be repaired through maintenance and inspection, and then operation can be resumed by manual operation, thereby preventing the compressor from repeatedly starting and stopping.

In short, the single low pressure switch 19 can perform the abnormal low pressure protection function and the pump down stop function, and can also prevent automatic recovery at the time of the abnormal stop.

[Brief explanation of drawings]

FIG. 1 is a refrigerant circuit diagram of a separate type refrigeration system according to the present invention, and FIG. 2 is an electric circuit diagram in which a compressor 1, fan motors 13, 14, etc. are used as loads. 4...Compressor, 7...Liquid receiver, 8...
...Expansion function, 11...Solenoid coil of solenoid valve, 12...Solenoid valve, 15,16...
Condenser fan, 19...Low pressure switch,
24... Abnormality detection relay, 27... Normally open contact of the abnormality detection relay, 33... Auxiliary relay, 34... Normally closed contact of the auxiliary relay, 36...
...Driving command relay, 37... Normally open contact of the driving command relay, 61... Protection circuit, 62...
Stop switch, 63... Run switch, 64.
...Thermo switch.

Claims (1)

[Scope of utility model registration request] A stop switch 62 and a run switch 6 connected to the power supply
A parallel circuit of the auxiliary relay 33 via the thermoswitch 64 for room temperature detection in the series circuit of 3, and the electromagnetic coil 11 of the electromagnetic valve 12 interposed in the refrigerant circuit 10 between the liquid receiver 7 and the expansion mechanism 8. At the same time, the compressor 4 is connected to a parallel circuit with a low pressure switch 19 connected to the power source that opens when the pressure is below a predetermined pressure, and a contact 50 that opens for a predetermined time in response to a signal from the thermoswitch 64 and then remains in between. A drive command relay 36 for issuing a drive command signal is connected in series, and a protection circuit 61 connected to the power source includes a normally closed contact 34 of the auxiliary relay 33 and a normally open contact 37 of the drive command relay 36. In the event of an abnormality, a parallel circuit is connected in series between the parallel circuit of the contact 29, which opens in response to a command from the operation switch 63, and closes in response to a command from the stop switch 62, and the normally open contact 25 of the abnormality detection relay 24. Connect the abnormality detection relay 24 that becomes de-energized, and
A refrigeration system characterized in that a normally open contact 27 is interposed in a parallel circuit of the low pressure switch 19 and the contact 50 and a series circuit of the operation command relay 36.