JPS5969678A - Temperature controller for refrigerator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a temperature control device for a refrigeration system, and more specifically, it detects the suction temperature of an evaporator and controls the capacity and starts/stops a compressor during refrigeration operation to control the temperature inside the refrigerator. The present invention relates to a temperature control device for a refrigeration device that prevents overcooling by controlling and detecting the Suita temperature of an evaporator and stopping a compressor.

Prior art temperature control device for refrigeration equipment (Japanese Patent Laid-Open No. 55-16
No. 5466), as shown in Figure 1, refrigerated items are stored at the suction (inside) temperature detected by the inside temperature sensing element (R5) installed in the duct (DT) of a sea container (SC). There are 10,000 types that control the temperature inside the refrigerator to keep it within a set range, and 10,000 types that prevent overcooling of refrigerated items using the air outlet temperature detected by an air outlet temperature sensing element (SS). In this kind of conventional temperature control device, for example, as shown in Fig. 2, there is a thermostat (Sl) for starting and stopping the compressor that turns on and off in response to the suction temperature detected by the internal temperature sensing element (R5). A capacity control thermostat (S2), an outlet temperature control thermostat (S3) that turns on and off in response to the outlet temperature detected by an outlet temperature and humidity sensing element (SS), and a normally closed contact (ARC+).

In combination with an auxiliary relay consisting of a normally open contact (ARC2) and a coil (AR), the solenoid valve (HV) installed in the hot gas bypass pipe and the solenoid valve (L
V) and a coil (AR) of an auxiliary relay that turns on and off the contacts (ARCI and ARC2) to perform pull-down operation and stable operation by capacity control within an appropriate temperature range. In internal temperature control using such a temperature control device, as shown in Figure 3, when the refrigeration operation switch of the refrigeration device is turned on and the compressor is started, the suction temperature (TR) and Suita temperature (TS) decrease. However, since it is full load operation, the suction temperature (TR) and outlet temperature (
When the temperature difference with TS) becomes large and the suction temperature (TR) reaches 2°C at time (1o), the blowout temperature (TS)
is below -3℃. Therefore, the capacity control thermostat (S2) turns on and the auxiliary relay coil (A
When R) is energized, the normally closed contact (ARCl) is turned off, and when the normally open contact (ARC2) is turned on, the blowout temperature control thermostat (S3) is already turned off, so the hot gas bypass electromagnetic The valve (HV) remains closed. Also, at this time, the liquid phase solenoid valve (L
Since V) is also set to 1 closed unit, the compressor will eventually stop even if the compressor start/stop thermostat (Sl) is on. As a result, both temperatures (TR)
(TS) The force is rising, but first time (t,)
When the Suita temperature (TS) reaches 0℃, the Suita temperature control thermostat (S4) turns on and the liquid phase solenoid valve (LV
) becomes 1 open, the compressor is started again, and in this case, since the normally open contact (ARC2) is on, the hot gas bypass solenoid valve (HV) also becomes 1 open, allowing low load operation. Become.

Next, when the one-car temperature (TR) (TS) decreases and the Suita temperature (TS) reaches -8° C. at time [t2], the Suita temperature control thermostat (S3) is turned off and the compressor is stopped.

In this manner, the compressor is repeatedly turned on and off by turning on and off the blowout temperature control thermostat (S3) from time [t3) to time (tl,). And suction temperature (TR)
When the temperature reaches 0° C. at time (t 12 ), the compressor start/stop thermostat (Sl) is turned off, so the compressor that has been started is stopped by turning on the blowout temperature control thermostat (S3). At this time, from 2) onwards, the suction temperature'
(TR) is low and the evaporation temperature is low, so the refrigerant circulation amount is small, and the hot gas bypass ratio is also large, resulting in a small cooling capacity.
3) is kept on, and the compressor is normally controlled in capacity by turning on and off the compressor thermostat (Sl), that is, starting and stopping at the suction temperature (TR).

By the way, as shown above, the suction temperature (TR) is set at 0°C.
During the transition period until normal capacity control operation starts, the compressor is repeatedly turned on and off due to the Suita temperature control thermostat [S3], that is, depending on the blowout temperature (Ts). The frequency of starting and stopping increases, which affects the durability of the compressor.

(11) It took a long time for the compressor start/stop control thermostat (Sl) to start and stop the compressor normally, causing problems such as deterioration of the quality of refrigerated items in the refrigerator.

In view of the above, the present invention prevents the compressor from being stopped by blowout temperature control to prevent overcooling during the transition period from the start of internal temperature control until regular capacity control operation by suction temperature control. By not doing so, the purpose is to quickly lower the suction temperature and shorten this transition period, thereby reducing the frequency of unnecessary starts and stops of the compressor and maintaining good quality of refrigerated products. .

The configuration of the present invention includes an internal temperature sensing element that detects the suction temperature of the evaporator and is used to control the internal temperature during refrigeration operation, and a temperature sensing element that detects the outlet temperature of the evaporator and is used to prevent overcooling. When the suction temperature detected by the outlet temperature sensing element and the interior temperature sensing element decreases to the lower limit of the first set temperature range, a low-load operation signal is output, and the temperature rises to the lower limit of the first set temperature range. The capacity control thermostat outputs a full-load operation signal when the upper limit is reached, and the suction temperature detected by the chamber temperature sensing element decreases to a second set temperature range that is lower than the first set temperature range. A compressor start/stop thermostat outputs a compressor stop signal when the lower limit is reached, and outputs a compressor start signal when the temperature rises to the upper limit of the second set temperature range, and the outlet temperature detected by the outlet temperature thermosensor. , Suita temperature control outputs a compressor stop signal when it decreases and reaches the lower limit of the supercooling prevention temperature range, which is lower than the second set humidity range, and outputs a compressor start signal when it rises and reaches the upper limit of the supercooling prevention range. and a counter that counts the number of times the compressor has stopped since the start of refrigeration operation in response to the output signal of the compression start/stop thermostat and outputs an activation signal when a predetermined count is reached, and an activation signal is output from the counter. Until the operation signal is output, the compressor is started and stopped by the output signal of the compressor start/stop thermostat regardless of the output signal of the blowout temperature control thermostat, and when the operation signal is output, the compressor is started and stopped. The circuit is configured to start the compressor in response to the output of a compressor stop signal from either of the two thermostats for temperature control, and the system is configured to prevent supercooling during the transition period from the start of refrigeration operation until it reaches a nearly steady state of operation. In order to prevent this, blowout temperature control is not performed.

Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

Embodiment 1 FIG. 4 is a diagram showing a refrigeration cycle of a marine container refrigeration system to which an embodiment of the present invention is applied.

In Fig. 4, the symbol is the compressor, () is the condenser, (Q is the temperature-sensitive expansion valve, ◎ is the constant pressure expansion valve, (6) is the evaporator, (F) is the fan, and (LV) is the high pressure The liquid phase solenoid valve installed in the liquid pipe (G), (HV) is the hot gas bypass solenoid valve installed in the hot gas bypass pipe ■, and the double electric valves (LV) and (HV) control the opening and closing of the valve. When an open signal is applied to the valve to open the valve, or a close signal to the valve is applied to the valve to close the valve, the valve is opened or closed, respectively. There is a pressure switch (not shown) that detects this, and when the liquid phase solenoid valve (LV) closes and the low pressure drops, this pressure switch is turned off and the compressor is stopped. There is.

FIG. 5 is a configuration diagram of a temperature control device that controls the refrigeration cycle shown in FIG. 4 to control the temperature inside the refrigerator, and parts corresponding to those in FIG. 2 are given the same reference numerals.

In FIG. 5, (s1XS2) is a thermostat that responds to the suction temperature (TR) detected by the internal temperature sensor (RS), and in particular (S2) is a thermostat that responds to the suction temperature (TR) as it decreases. 1 set temperature range (Ts2) (e.g. 2℃
When the lower limit of 2°C (~8°C) is reached, the contact turns on and outputs a low-load operation signal, and the temperature rises to the first set temperature range (Ts,
) is a capacity control thermostat that turns off the contact and outputs a full load operation signal when the upper limit of (S
In l), the suction temperature (TR) detected by the internal temperature sensing element (R5) decreases to a second set temperature range (TSl) lower than the first set temperature range (TS, ) (e.g. θ℃~
When the lower limit of 0°C (1°C) is reached, the contact turns off and outputs a compressor stop signal, and the temperature rises to the second set temperature range (Tsl).
This is a compressor start/stop thermostat that turns on the contact and outputs a compressor start signal when the temperature reaches the upper limit of 1°C. [S3
) is the outlet temperature (
TS) decreases to the second set temperature range (TSl).
When the lower limit of the supercooling prevention temperature range (Ts3) (e.g. 0°C to -8°C) is reached, the contact turns off and outputs a compressor stop signal, and the temperature rises to exceed the supercooling prevention temperature range (Ts3).
When the upper limit of s3) is reached, the contact is turned on and a compressor start signal is output.

(CT) responds to the output signal of the compressor start/stop thermostat (Sl), for example, a compressor stop signal, and counts the number of times the compressor (a) has stopped since the start of refrigeration and operation, and calculates a predetermined number of counts (for example, This is a counter that outputs an activation signal when the 3rd time. (Foundation) is a normally closed contact (ARCI).

An auxiliary relay consists of two normally open contacts CARC2) (ARC3) and a coil (AR) that is energized by the low load operation signal of the capacity control thermostat (S2), and a normally open contact that is turned off by the activation signal of the counter (CT). Closed contact (C
TC). In addition, (S4) is a thermostat for indicating the optimum temperature that turns off when the suction temperature (TR) decreases to, for example, -3℃, and turns on when it rises to, for example, -2℃. (LP) is a lamp that indicates the optimum temperature. It is.

Next, the operation will be explained.

First, the refrigeration operation switch of the refrigeration device is turned on and pull-down operation is started. With this start, the compressor (A) starts up and the suction temperature (TR) and outlet temperature (TS) decrease as shown in Figure 6, but since it is operating at full load, the difference between the two temperatures is large. Become. At time (tOQ), the suction temperature (TR) reaches 2° C., which is the lower limit of the first set temperature range CTS2). At the same time (too), the outlet temperature (Ts)
is below -3°C, which is the lower limit of the supercooling prevention temperature range (TS3). For this reason, the capacity control thermostat (S2
) is turned on, a low load operation signal is generated, and the auxiliary relay coil (AR) is energized. This energization turns off the normally closed contact (ARCl) and turns off the normally open contact (ARC2) (AR
C3) is turned on, but at this time the Suita temperature control thermostat (S3) is also already turned off. However,
A normally closed contact (CTC) in parallel with the blowout temperature control thermostat C83) remains on until an activation signal is output from the counter CCT) when the compressor (5) stops a predetermined number of times (for example, 3 times). It remains as it is. For this reason, a hot gas bypass electric valve (HV) and a liquid solenoid valve (LV) are installed.
Even if both the normally closed contact (ARC1) and the blowout temperature control thermostat (S3) are off, the compressor start signal from the compressor start/stop thermostat (Sl) is used as an open signal to connect the normally closed contact (CTC). continues to be entered via. As a result, the compressor (3) is connected to the Suita temperature control thermostat (S
3) does not stop even when the switch is turned off, and switches from full load operation to low load operation at time (too), and both temperatures (T
The rate of decrease in R) (Ts) becomes slower, and both temperatures (TR) (TS) further decrease.

Next, at time (t2o), the suction temperature (TR) reaches the second level.
When the temperature reaches 0° C., which is the lower limit of the set temperature range (Ts,), the compressor start/stop thermostat (Sl) is turned off and a compressor stop signal is generated. This signal is a normally open contact (CTC)
) is given as a close signal to both electromagnetic valves ()TV) (LV), and is also given to the counter (eT) via a normally open contact (ARC3). Therefore, 1-car solenoid valve CH
V) (LV) both become "closed", the compressor (2) stops, and the count number of the counter (CT) becomes "1". In this way, by stopping the compressor, both temperatures (
TR) (TS) is rising. Both temperatures (TR)
CTs), even if the blowout temperature (TS) reaches 0℃, which is the upper limit of the supercooling prevention temperature range (TS3), and the blowout temperature control thermostat (S3) is turned on, there is no change in the stoppage of the compressor. . On the other hand, the suction temperature (TR) is determined by the time (t3o
), which is the upper limit of the second set temperature range (TSl).
When it comes to ℃.

The compressor start/stop thermostat (S) turns on and a compressor start signal is generated. This signal is sent to both solenoid valves (LV) (HV) via the normally closed contact (CCTC) which is turned on. given as a signal. As a result, both the solenoid valves (LV) and (HV) become "open" and the compressor (3) is started. Therefore, at time (13 o), both temperatures (TR) (TS)
decreases.

In this way, at the time (17o) when the compressor (4) has stopped a predetermined number of times, that is, 8 times, an activation signal is generated from the counter (CT), so that the normally closed contact (
Until the CTC) is turned off, the compressor is started and stopped by turning on and off the compressor starting/stopping thermostat (S), regardless of the output signal of the Suita temperature control thermostat (S3). Then, the compressor ■ is operated at the time (17
o) From then on, the compressor is stopped by the compressor stop signal of either one of the thermostats I-(S, )(S3) for compressor start/stop and Suita temperature control, that is, either one is turned off. Both thermostats (S+
) (S3'), that is, the compressor is activated only when both of them are turned on.

Therefore, according to this embodiment, during the transitional period from the start of refrigeration operation to the time (t7o) when the operation becomes almost steady, the outlet temperature control for supercooling and rain prevention is not performed, and after this transitional period, the Suita temperature By quickly lowering the suction temperature through control, the transition period is shortened and the frequency of compressor startup and shutdown is reduced.

FIG. 7 is a circuit diagram when the embodiment shown in FIG. 4 is applied to another electric circuit, and parts corresponding to those in FIG. 5 are given the same reference numerals. In FIG. 7, the code amount is the first and second set temperatures and the thermostat for displaying the appropriate temperature (
Volume to adjust the set temperature of B4), CB, ) to (
B3) is the volume (goods) and internal temperature sensing element (R5)
first to third converters that convert into electrical signals corresponding to the respective electrical resistances of the temperature sensing element (SS) and the temperature sensing element (SS);
MP) is an amplifier that amplifies and outputs a signal corresponding to the difference between the m first converter (B, ) and the second converter (B2), and (A
NDI) to (AND5) and (T) are first to fifth AND circuits and inverters, respectively, as circuit means [M'). (Sl) to (S, ) are thermostats corresponding to FIG. 5, and each thermostat (Sl) to (B4) is an internal temperature sensing element (R8) and an outlet temperature sensing element (SS). Detected suction temperature (TR)
, each converter (B1) corresponding to the blowout temperature (Ts) ~
The output signal from (B3) is converted into a reference signal (V,) to (v4
) is a logical “1” or “0” by comparing between
Outputs the signal. The thermostat (S, ) (B3) for compressor start/stop and blowout temperature control outputs a logic "1" signal as a compressor start signal, a logic "0" signal as a compressor stop signal, and outputs a logic "0" signal as a compressor stop signal. B2) outputs a logic rOJ as a full load operation signal and a logic "1" signal as a low load operation signal. Furthermore, each of these thermostats (Sl) to (B3) outputs each of the above-mentioned signals in response to each change in the suction temperature (TR) and the blowout temperature (Ts) in the same manner as in FIGS. 5 and 6. ing. counter(
CT) counts each time a compressor stop signal of logic "0" is input from the compressor start/stop thermostat (So), and outputs a logic "0" from the capacity control thermostat (B2).
When a low load operation signal of "1" is input via the inverter (I), it is set to be able to count, and when the count reaches a predetermined number (for example, 3 times), the logic "1" is set.
” is output, and the logic “0” is output until the predetermined number is reached.
” signal is output.

Next, the operation of this circuit will be explained.

First, the refrigeration operation switch is turned on and pull-down operation starts. With this start, the first. Each thermostat (for compressor start/stop and capacity control) is connected via the second converter (B2) and amplifier CAMP).
S+) (B2) with the suction temperature (TR) and the volume M
The signal corresponding to the value adjusted by is also sent to the third converter (B3
), signals corresponding to the blowout temperature (Ts) are respectively input to the blowout temperature control thermostat (B3). At the start, both temperatures (TR) and (TS) are high;
Each thermostat [51) (B3) for compressor start/stop and Suita temperature control is activated by the corresponding input signal.
1" compressor start signal to the capacity control thermostat (
B2) respectively output a full load operation signal of logic "0". For this reason, 1. Fifth AND circuit (AND+) (
ANDs ) are the open signal of logic “1” and the logic “0” respectively.
” outputs a close signal. For this reason, the liquid solenoid valve (LV)
is set to "open", and the hot gas bypass solenoid valve (HV) is set to "open".
Closed. The device is thus in full load operation. Through this operation, the blowout temperature (TS) is adjusted to the supercooling prevention temperature range (T
When the temperature reaches -8°C, which is the lower limit of S3), the third converter (B3
), the Suita temperature control thermostat (B3) outputs a logic "0" compressor stop signal, and the Nishigome temperature (TR) has reached the lower limit of the first set temperature range (TS2), causing the capacity to rise. The control thermostat (B2) is
1" low load operation signal is output and the fourth AND circuit (AN
D4) outputs a logic "1" signal. However, since the counter (CT) is outputting a logic "0" signal,
The second AND circuit (AND2) is the fourth AND circuit (AND
, ) outputs a logic "1" signal, it outputs a logic "0" signal. In other words, the thermostat for controlling the blowout temperature (
B3) is not involved in starting or stopping the compressor (a) until the counter (CT) outputs an operating signal of logic "1".

That is, in this case, the first AND circuit (ANDl) operates according to the output signal of the compressor start/stop thermostat (Sl).
The fifth AND circuit (AND5) is the first AND circuit (AND
, ) and the output signal of the capacity control thermostat (B2), a logic "1" or "0" signal is output.

Then, the suction temperature (TR) is within the first set temperature range (Ts2
), the capacity control thermostat (S2
) outputs only a logic "1" signal, so the fifth AND circuit (AND5) outputs a logic "1" and the hot gas bypass solenoid valve (HV) is opened, resulting in low load operation. In addition, the liquid phase solenoid valve (LV) is the thermostat for starting and stopping the compressor (
The output signal of the compressor (
b) is started and stopped.

In this case, the compressor ■ starts up due to the low load operation and the heat capacity of the refrigeration system including the evaporator (T).
S ) becomes smaller. In this way, when the number of stops of the compressor reaches a predetermined number of times (1, for example, 3) and the counter (CT) outputs an operation signal of logic "1", the first and fifth AND circuits (AND+) CAND5) ．． The compressor (2) is activated by the compressor stop signal of -10,000 logic "0" of the blowout temperature control thermostat (S3) and the compressor start/stop thermostat (S,) via the fourth AND circuit (AND2) (AND4). It is possible to output a close signal of logic "10" to stop the compressor (1), and output an open signal to start the compressor (a) by means of both compressor start signals of logic "1". In addition.

In this example, the time for the blowout temperature (TS) detected by the Suita temperature sensor (SS) to be below the lower limit of the supercooling prevention temperature range is longer than in the conventional example; Since the temperature in the refrigerator does not match the temperature inside the refrigerator, there is no risk of the refrigerated items freezing.

<Embodiment 2> FIG. 8 is a diagram showing a refrigeration cycle in another embodiment of the present invention, and parts corresponding to those in FIG. 4 are given the same reference numerals. In FIG. 8, a capillary tube (TB) is provided in the hot gas bypass pipe (2) [However, a constant pressure expansion valve may be used, or only a pipe may be used. ) An auxiliary hot gas bypass pipe (H') is provided by branching in parallel to this capillary tube (TB), and an auxiliary hot gas bypass solenoid valve (HV') is connected to this auxiliary hot gas bypass pipe (H').
The rest of the configuration is the same as that shown in FIG. 4.

FIG. 9 is a diagram showing the configuration of another embodiment of the present invention corresponding to the above-mentioned refrigeration cycle, and parts corresponding to those in FIG. 5 are given the same reference numerals. The configuration of FIG. 9 is based on the circuit means (M”
) has an auxiliary capacity control thermostat (S3/), and an auxiliary hot gas bypass solenoid valve (HV') is inserted in series with this thermostat (S3'). It is similar to the figure.

The auxiliary capacity control thermostat (83') controls the blowout temperature (
TS) is turned on when it falls to the lower limit (e.g. -2.4°C) of the third set temperature range (T53'), and rises to the upper limit (e.g. -1.2°C) of the third set temperature range (T83'). ), it turns off.

Next, the operation will be explained with reference to FIG.

When the refrigeration operation switch is turned on, the compressor start signal of the compressor start/stop thermostat (S,
) starts, and both the suction and blowout hot dust (TR) (TS) rapidly decrease during full load operation. In this case, as in the embodiment shown in FIG.
When the lower limit of the set temperature range (TS2) reaches 2°C, the Suita temperature (TS) has already reached the supercooling prevention temperature range (T
The temperature will be below -4°C, which is the lower limit of B3). Therefore, the capacity control thermostat (S2) turns on, the normally closed contact (ARC,) turns off, and the normally closed contact (ARC2) (AR
When C3) is turned on, the blowout temperature control thermostat (S3) is already turned off. However, since the counter (CT) does not output an activation signal, the normally closed contact (CTC) remains on, and the auxiliary capacity control thermostat (S3') also decreases in temperature (Ts) and reaches the 8th point. It is the lower limit of the set temperature range (T53') -
Since it is on for temperatures below 2.4℃, all solenoid valves (H
V') (HV) (LV) becomes "open" and both temperature dust (TR)
(TS) gradually decreases during the first low load operation. Then, at time (t2.'), the suction temperature (TR) reaches the second level.
When the temperature reaches 0° C., which is the lower limit of the set temperature range (TS), the compressor start/stop thermostat (Sl) is turned off and a compressor stop signal is output.

This serves as a closing signal for all solenoid valves (HV') (HV) (
LV ) given to the solenoid valve (HV') (HV)
(LV) becomes "closed" and the compressor (4) stops. As a result, the temperature dust (TR) (Ts) rises and the time (t
3o'), when the suction temperature (TR) reaches 1°C, which is the upper limit of the second set temperature range (Ts, ).

The compressor start/stop thermostat (S,) is turned on and a compressor start signal is output. At this time, the blowing temperature (TS
) is the upper limit of the third set temperature range (TS3') -12
Since the temperature is higher than 0.degree. C., the auxiliary capacity control thermostat (S3') is turned off. For this reason, the electric i-valve for liquid (
LV) and hot gas bypass solenoid valve (Hv) open.
, the auxiliary hot gas bypass solenoid valve C') is closed, the compressor (a) starts, and both hot gas (TR) (TS
) decreases as shown in Fig. 10 during the second low-load operation.

However, at time (t4o'), the blowout temperature (Ts
) is the lower limit of the third set temperature range (TS3') -2.
When the temperature reaches 4℃, the auxiliary capacity control thermostat (S3')
is turned on and the auxiliary hot gas bypass solenoid valve (f(
Set V to "open". As a result, all solenoid valves (LV)
()IV) (HV') becomes "open" and both hot dust (T
R) (TS) decreases at a lower rate. Blowout temperature (T
The suction temperature (TR) is at the lower limit of the second set temperature range (Ts, ) at the time ([5 o') before s) becomes below -4℃, which is the lower limit of the supercooling prevention temperature range (TS3).
℃, the compressor start/stop thermostat (S,) is turned off, a compressor stop signal is output, and all solenoid valves (LV) (
When HV') (HV) becomes "closed", the compressor (4) stops. In this way, the compressor (4) is repeatedly turned on and off until one time (tso') by turning on and off the compressor starting/stopping thermostat (Sl). By the way, the compressor (
When the number of stops in b) reaches a predetermined number, for example, three times, an activation signal is generated from the counter (CT), and this activation signal turns off the normally closed contact (CTC). Therefore, the blowout temperature control thermostat (S3) can perform the normal overcooling prevention operation after time (t++o'). That is, at time (t1oo') (t, 2o'), the compressor start/stop thermostat (Sl) causes the time (t+
to' ) is the thermostat (S3) for controlling the blowout temperature.
The compressor is stopped and 1 time (tno') (tlg(
1'), the compressor starts/stops the thermostat (Sl), and at time (t160'), the Suita temperature control thermostat (S3) starts the compressor (2). Note that the time (t90') (t14n') is the time when the auxiliary hot gas bypass solenoid valve (HV') is "opened" by the auxiliary capacity control thermostat (S3').

In this way, in this embodiment, by performing low-load operation in two stages, when the outlet temperature control thermostat (S3) is prevented from operating normally during the transition period before entering stable operation, the suction temperature control thermostat (S3) is Sudden overcooling is prevented by suppressing the sudden drop in the blowout temperature (Ts) before the temperature (TR) reaches 0°C, and normal operation can be performed when stable operation is achieved. A Suita temperature control thermostat (S3) is used to directly prevent overcooling.

FIG. 11 is a circuit diagram in which the embodiment of FIG. 9 is applied to another electric circuit, and parts corresponding to those in FIGS. 7 and 9 are given the same reference numerals. The circuit shown in Fig. 11 is the circuit shown in Fig. 7 plus a sixth AND circuit (AND
5') and auxiliary hot gas bypass solenoid valve (HV')
The circuit has the same configuration as the circuit shown in FIG. 7, except that the circuit shown in FIG. In addition, in the circuit shown in Fig. 11, when the auxiliary hot gas bypass solenoid valve (HV') is turned off by the sixth
When the AND circuit (AND5') is turned "open" by the logic "1" open signal and the outlet temperature (CTS) rises to -1.2°C, the sixth AND circuit (AND5') is opened.
The circuit operates in such a way that it is "closed" by a logic "0" close signal from ), and other than that, the circuit operation is the same as the circuit shown in FIG.

It should be noted that the second embodiment has an advantage over the first embodiment in that it can prevent a sudden drop in the Suita temperature (Ts) while preventing the compressor (8) from starting and stopping during pulldown.

In the explanation of the above embodiment, hot gas bypass was performed by opening the hot gas bypass solenoid valve during low load operation.
Known low-load operation in which the compressor rotates at a low speed or the compression volume of the compressor is gradually reduced (for example, in the case of a reciprocating compressor, some of the cylinders are unloaded) You can also do this. In addition to the above embodiments, a microcomputer may be used as the electric circuit.

In this case, each thermostat is constituted by a microcomputer, and the microcomputer performs the functions of each thermostat. Furthermore, regarding the first and second set humidity ranges and supercooling prevention humidity range, the upper limit of the set temperature range on the low temperature side may be higher than the lower limit of the set temperature range on the high temperature side, and the center of the set temperature range on the low temperature side. It is sufficient that the value is lower than the center value of the set temperature range on the high humidity side.

As described above, according to the present invention, an internal temperature sensor element is used to detect the suction temperature of the evaporator and control the internal temperature during refrigeration operation, and a temperature sensing element is used to detect the air outlet temperature of the evaporator and is used to control the internal temperature during refrigeration operation. When the suction temperature detected by the outlet temperature sensing element used for cooling prevention and the inside temperature sensing element decreases to the lower limit of the first set temperature range, a low load operation signal is output and the temperature increases. 1st
The capacity control thermostat outputs a full-load operation signal when the upper limit of the set temperature range is reached, and the suction temperature detected by the internal temperature @ temperature element decreases to a second setting lower than the first set temperature range. A compressor start/stop thermostat outputs a compressor stop signal when the temperature reaches the lower limit of the temperature range, and outputs a compressor start signal when the temperature rises to the upper limit of the second set temperature range, and the blowout temperature is detected by a thermosensor. When the blowout temperature falls and reaches the lower limit of the supercooling prevention humidity range, which is lower than the second set temperature range, a compressor stop signal is output, and when it rises and reaches the upper limit of the supercooling prevention range, a compressor start signal is output. A counter that counts the number of times the compressor has stopped since the start of refrigeration operation in response to the output signals of the blowout temperature control thermostat and the compression start/stop thermostat, and outputs an activation signal when a predetermined count is reached; Is it a balloon until the signal is output? The compressor is started and stopped by the output signal of the compressor start/stop thermostat regardless of the output signal of the thermostat for temperature control, and when the operation signal is output, the The circuit is configured to start the compressor in response to the output of a compressor stop signal from either thermostat, and is used to prevent overcooling during the transition period from the start of refrigeration operation to the almost steady state of operation. Since blowout temperature control is not performed, the compressor should not be stopped by blowout temperature control to prevent overcooling during the transition period until regular capacity control operation is achieved by suction temperature control. This reduces the suction temperature quickly and shortens this transition period.
As a result, the frequency of unnecessary starting and stopping of the compressor can be reduced and the quality of refrigerated products can be maintained at a good level.

[Brief explanation of drawings]

Figures 1 to 3 show conventional examples, Figure 1 is a schematic configuration diagram of a marine container refrigeration system, Figure 2 is an electric circuit diagram showing a temperature control device, and Figure 3 is the suction temperature and Suita temperature. 4 to 7 show an embodiment of the present invention,
Fig. 4 is a diagram showing the refrigeration cycle, Fig. 5 is an electric circuit diagram showing the temperature control device, Fig. 6 is a diagram showing changes in suction temperature and Suita temperature, Fig. 7 is another electric circuit diagram, Figure 8-1
1 shows another embodiment of the present invention, FIG. 8 is a diagram showing a refrigeration cycle, FIG. 9 is an electric circuit diagram showing a temperature control device,
FIG. 10 is a diagram showing changes in suction temperature and Suita temperature, and FIG. 11 is another electrical circuit diagram. (R5)... Suction temperature sensing element, (SS)... Suita temperature sensing element, (3)... Compressor, (S,)... Thermostat for compressor start/stop, (S2) ... Thermostat for capacity control, (S3) ... Thermostat for blowout temperature control, (ARC:t) (CTC) ... Normally closed contact, (ARC2) (ARC3) ... Normally open contact, (
CT)...Counter, (AR)...Auxiliary relay coil, (HV) (HV')...Solenoid valve for hot gas bypass, (LV)...Solenoid valve for liquid, CM)
CM') (M") CM"')...Circuit means, (AND
+) ~ (AND5) (AND5 Q...And circuit, (■)...Inverter applicant Daikin Industries, Ltd. agent Patent attorney Kazuhide Okada

Claims (1)

[Claims] (1) An internal temperature sensing element (R9) used to control the internal temperature during refrigeration operation by detecting the suction temperature (TR) of the evaporator and the outlet temperature (Ts) of the evaporator Suita temperature sensing element (SS) used to detect and prevent overcooling
and the suction temperature (
A capacity control thermostat (S2) that outputs a low-load operation signal when TR) decreases and reaches the lower limit of the first set temperature range, and outputs a full-load operation signal when it rises and reaches the upper limit of the first set temperature range. Then, when the suction temperature (TR) detected by the refrigerator temperature sensing element (R5) decreases to the lower limit of the second set temperature range, which is lower than the first set temperature range, a compressor stop signal is output. The compressor start/stop thermostat (Sl) outputs a compressor start signal when the temperature rises to the upper limit of the second set temperature range, and the blowout temperature (TS) is detected by the blowout temperature sensing element (SS). ) decreases and reaches the lower limit of the supercooling prevention temperature range, which is lower than the second set temperature range, a compressor stop signal is output, and when it increases and reaches the upper limit of the supercooling prevention temperature range, a compressor start signal is output. In response to the output signals of the Suita temperature control thermostat (S3) and the compressor start/stop thermostat (Sl), the number of times the compressor is stopped from the start of refrigeration operation is counted, and when a predetermined count is reached, an activation signal is sent. Output counter (CT), counter (C
Until the activation signal is output from T), the compressor (
A) is started and stopped, and when the activation signal is output, both the thermostats for starting and stopping the compressor and for controlling the Suita temperature (
SL) (S3) to stop the compressor (4) by outputting a stop signal, and to start the compressor (a) by outputting both start signals. Temperature control device.