JPH01123976A - Cold temperature regulator - Google Patents

Abstract

PURPOSE: To perform cooling/heating over a wide temperature range while protecting a cooler/heater by disposing a temperature detector above a heater in a liquid tank and providing a protector for sustaining a refrigerant compressor and a heater in stopped state depending on the detected temperature. CONSTITUTION: When the temperature of brine in a lower brine chamber 7B of a liquid tank 7 increases over 55 deg.C due to some cause, a protective thermo 25 is opened by a temperature signal from a temperature-sensitive tube 251. Consequently, power supply to a compressor motor and a fan motor is interrupted to block refrigerant flow to a refrigeration cycle thus protecting a refrigerant compressor 1 and the compressor motor. When brine is not present in the tank 7 and idle burning takes place in the lower brine chamber 7B, a temperature-sensitive tube 241 of a protective thermo 24 detects radiation heat from a heater 8. When the detected temperature exceeds 90 deg.C, the protective thermo 24 is opened to interrupt power supply to the heater 8, the compressor motor and the fan motor.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial Application Field The present invention reduces the load of plastic molding molds, etc. installed at a location away from the main body of the device by using cold and temperature-controlled brine (
This invention relates to a cooling and temperature control device used to maintain a set temperature using water (water or liquid).

(Example) Conventional technology In the past, as this type of cooling and temperature control device, for example,
- As disclosed in Publication No. 15107, brine is stored to be supplied to the load through a refrigerant circuit that connects a refrigerant compressor, an evaporator, etc. to form a refrigeration cycle, and a brine circulation path having a circulation pump. Equipped with a liquid tank,
A liquid cooling device is known that cools brine by accommodating an evaporator in a liquid tank.

(c) Problems to be Solved by the Invention The liquid cooling device described above cannot be used for a load that requires maintaining a temperature higher than room temperature, such as a mold for plastic molding. Of course, if a heater is installed inside the liquid tank and the brine temperature is adjusted using both the heater and the evaporator, it is possible to control the cooling temperature of the load over a wide range, but if the brine is excessively heated, the refrigerant is compressed If the machine was operated, there was a risk of damaging the refrigerant compressor, and if there was no brine in the liquid tank and dry firing was performed, there was a risk of damaging the liquid tank.

This invention was made in view of the above facts,
The purpose is to enable cooling and temperature control over a wide temperature range and to protect the equipment.

(d) Means for Solving the Problems In this invention, brine is supplied to the load via a refrigerant circuit that connects a refrigerant compressor, an evaporator, etc. to form a refrigeration cycle, and a brine circulation path that has a circulation pump. A temperature sensor is provided above the heater inside the liquid tank in a cold temperature control device that includes a liquid storage tank, houses an evaporator and a heater inside the liquid tank, and adjusts the amount of heat generated by the heater according to the brine temperature. is provided, and the refrigerant compressor is stopped when the detected temperature of the temperature detector is equal to or higher than the first predetermined temperature T1, and the refrigerant compressor is stopped when the detected temperature is set to a second predetermined temperature T higher than T1.
The configuration is equipped with a protection device that maintains the refrigerant compressor and heater in a stopped state when the number is 2 or more.

(E) Effect With this configuration, the brine temperature can be controlled over a wide range by the cooling operation by the refrigeration cycle and the adjustment of the heat generation amount of the heater.

Further, since the refrigerant compressor is stopped when the brine temperature in the liquid tank reaches the first predetermined temperature or higher, there is no fear of damaging the refrigerant compressor even if the brine is overheated. Furthermore, when dry firing is performed, the temperature detector above the heater receives radiant heat and detects a temperature equal to or higher than the second predetermined temperature, so the refrigerant compressor and heater are maintained in a stopped state, and the entire system is Protection will be provided.

(f) Example Hereinafter, embodiments of the present invention shown in the drawings will be described.

In Figure 1, (A) represents a refrigerant compressor (1), a condenser (
2), a fan (3), a dryer (4), an evaporator (5) formed of a coiled steel pipe, and an accumulator (6), and is a cooling device that constitutes a refrigeration cycle. Front-3 = 2 The evaporator (5) is located at the top inside a liquid tank (7) made of stainless steel or the like with an open top, and a heater for adjusting the brine temperature is installed at the bottom of the liquid tank (7). (8) is provided. Furthermore, by providing a partition plate (10) having a circular liquid passage port (9) between the evaporator (5) and the heater (8), the inside of the tank (7) can be connected to the upper brine chamber (7A). It is divided into two into a lower brine chamber (7B). (B) is a brine circulation path, in which the brine of the liquid tank (7) of the device body is separated from the outlet (73) by using the circulation pump (11) provided inside the device, and is loaded with molds, etc. (12) via a manual valve (13), and the brine that has undergone heat exchange with the load (12) is returned to the inside of the apparatus via a manual valve (14). The brine circulation path (B) branches into two systems on the return side, and is connected to a first inlet (71) and a second inlet (72) by a tank upper return pipe (20) and a tank lower return pipe (21), respectively. It is designed to flow into the upper and lower parts of the tank through the tank. Tank top return pipe (2
0) to make the pipe line thinner than the tank lower return pipe;
And a resistor (22) in the tank lower return pipe (21)
By adjusting the setting, the amount of brine flowing into the upper part of the tank is restricted. The brine that has flowed into the upper brine chamber (7A) is completely cooled by the evaporator (5), passes through the liquid passage port (9) of the tank partition plate (10), and flows into the lower part of the tank, resulting in two streams of brine flow. merge.

In addition, a temperature sensor (
15), and the control device (16) controls the cooling device (A).
) and by controlling the heater (8) on and off, the brine temperature (e.g. 15-50°
C) to keep the temperature of the load (12) outside the device constant with high accuracy.

The manual valves (17) and (18) are for draining the circulation pump (11) and the liquid tank (7), respectively.The reference water level (19) in the tank (7) is set to the evaporator (5).
) so that it is completely soaked.

In addition, the circular liquid passage port (
By appropriately changing the diameter of brine (9), it is possible to adjust the flow rate near the port (9) where brine flows from the top of the tank to the bottom of the tank, allowing it to flow from the top of the tank to the bottom of the tank at a certain flow rate. By doing so, it is possible to prevent high-temperature brine from flowing from the lower part of the tank to the upper part of the tank, and to prevent an excessive rise in temperature of the brine in the upper brine chamber (7A).
) can promote efficient heat exchange. In this example, the cooling capacity of the cooling device (A) is 1800 Kcal
/ h.

The capacity of the heater (8) is 3KW.

(23) is the lower brine chamber (7B) of the liquid tank (7)
The vibrator (23) is inserted above the heater (8), and both ends of the vibrator (23) are attached to the liquid tank (7) in a liquid-tight manner. Two temperature-sensing tubes (241) and (251) as temperature detectors are inserted into this vibrator (23) from both sides, and these temperature-sensing tubes (241 and 251) each have a protective device that allows temperature settings. Protective thermos as a device (2
4) Connected to (25) via a capillary tube or the like. Further, the protection thermos (24) (25) are connected to the control device (16).

FIG. 2 is an electrical circuit diagram of the control device (16).
) is the three-phase AC power supply, ri27) is the operation switch, (28)
is a compressor motor for driving the refrigerant compressor (1), (2
9) is a fan motor for driving the blower (3), (30) is a pump motor for driving the circulation pump (11), and (31) (
32) and (33) are electromagnetic contactors, (34) is a step-down transformer, (35) is a DC constant voltage circuit, (36) is a logic circuit, (37> is a transistor, (38) is a relay, (39) is a
) compares the voltage across a temperature sensor (15) such as a thermistor with the voltage across a temperature setting device (40) made of a variable resistor, and controls the heater on and off via solid state relays (41) and (42). This is a temperature control circuit, and these and protective thermostats (24) and (25) are connected as shown.

The protective thermostat (24) is set to, for example, 90° C., and is of a manual reset type. In addition, a protective thermometer (25
) is set at 55°C, for example, and an automatic reset type is used. The logic circuit (36) is connected to the operation switch (27
) is used to prohibit the operation of the compressor motor (28) and fan motor (29) from the time the brine temperature first exceeds the set temperature. That is, the temperature control circuit (39) issues an off command, and the output line (
When the current stops flowing through 43〉, the transistor (37)
is turned on, the compressor motor (28) and fan motor (29) are started, and then the temperature control circuit (39) is turned on.
) are operated regardless of the Of course, if the temperature control circuit (39) has issued an off command from the beginning, the compressor motor (28) and fan motor (29) are activated at the same time as the operation switch (27) is turned on.

Next, the operation of the above-described embodiment device will be explained. While the operation switch (27) is turned on, the refrigerant compressor (1) and the blower (3) are driven by the compressor motor (28) and fan motor (29), and the refrigeration cycle is operated. Therefore, the brine is cooled by the evaporator (5) in the upper brine chamber (7A). Further, the temperature control circuit (39) controls the heater (8) on and off, and the brine in the lower brine chamber (7B) is appropriately heated. The brine in the upper brine chamber (7A) is supplied to the liquid passage port (10).
) and mixed with the brine in the lower brine chamber (7B) before being sent to the load (12), so the temperature of the brine supplied to the load (12) is maintained approximately at the set temperature.

In this way, while operating the refrigeration cycle, the heater (
Since the on/off control of 8) is performed, the brine temperature (load temperature) can be controlled over a wide range.

If the brine temperature in the lower brine chamber (7B) rises for some reason and exceeds 55°C, the protective thermometer (25)
is opened by the temperature signal from the temperature sensing tube (251).

As a result, the compressor motor (28) and the fan motor (29) are de-energized and refrigerant no longer flows into the refrigeration cycle, causing the refrigerant compressor (1) and the compressor motor (29) to stop flowing.
28) will be protected. As a result, the brine temperature exceeds the set temperature and the heater (8) is no longer energized.
When the brine temperature in the lower brine chamber (7B) falls to a certain extent, the protective thermometer (25>) closes and the cooling and temperature control operation resumes.

In the unlikely event that there is no brine inside the liquid tank (7) and empty heating is performed in the lower brine chamber (7B), the protective thermometer (
The temperature sensing cylinder (241) of 24) senses the radiant heat of the heater (8). Then, the temperature detected by the thermosensor tube (241) is 90°.
When the temperature exceeds C, the protective thermometer (24) opens and the heater (
8), compressor motor (28) and Hifan motor (
29) Turn off the power. In this case, after investigating the cause and taking appropriate measures, the cooling and temperature control operation can be restarted by manually returning the protective thermometer (24).

In addition, in the above-mentioned embodiment, separate temperature sensing tubes (241) are used.
(251) were used as the protective device, but a temperature detector such as a thermistor was installed above the heater (8) inside the liquid tank (7) to detect the temperature. The refrigerant compressor (1) is stopped when the detected temperature of the refrigerant is equal to or higher than the first predetermined temperature T1.
When the predetermined temperature exceeds 12, which is higher than 1, the refrigerant compressor (1
) and a protection device that stops the heater (8) may be used.

(G) Effects of the Invention Since the present invention is configured as described above, the brine temperature can be controlled over a wide range by using a refrigeration cycle and a heater in combination, and the load on plastic molding molds, etc. can be maintained at the required temperature. Furthermore, it is a useful technology that not only reduces the negative impact of heater heating on the refrigeration cycle and protects the refrigerant compressor, but also protects the entire device by preventing dry firing. It is something.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a cooling and temperature control device showing an embodiment of the present invention, and FIG. 2 is an electric circuit diagram showing an example of the control device shown in FIG. 1. (A)... Refrigerant circuit, (B)... Brine circulation path, (1)... Refrigerant compressor, (5>... Evaporator,
(7)...Liquid tank, (8)...Heater, (1
1)...Circulation pump, (12)...Load, (16
)...control device, (24)(25)...protective thermometer (protective device), (241)(251)...temperature sensing tube (temperature detector).

Claims (1)

[Claims] (1) A refrigerant circuit that connects a refrigerant compressor, an evaporator, etc. to form a refrigeration cycle, and a liquid tank that stores brine to be supplied to a load via a brine circulation path having a circulation pump, and the liquid tank In a cold temperature control device that accommodates an evaporator and a heater inside the liquid tank and adjusts the calorific value of the heater according to the brine temperature, a temperature sensor is installed above the heater inside the liquid tank, and the temperature detected by this temperature sensor is It is characterized by comprising a protection device that stops the refrigerant compressor when the detected temperature is higher than a first predetermined temperature T1, and maintains the refrigerant compressor and the heater in a stopped state when the detected temperature reaches a second predetermined temperature T2 higher than T1. Cooling and temperature control equipment.