JPH07294099A - Cryostatic warehouse - Google Patents

Abstract

PURPOSE:To control the heat generation rate of an antisweating heater at an optimum by a simple construction in a warehouse wherein temperature can be controlled within the range from a freezing zone to a refrigerating zone. CONSTITUTION:An open showcase 1 is provided with an antisweating heater 17 installed on both a hand rail 14 and a wind deflection plate 16, a temperature controlling device for controlling temperatures within a warehouse ranging from a freezing zone to a refrigerating zone, a thermostat 41 which closes a contact point in the freezing zone and open the contact point in the refrigerating zone according to temperature of cooled air circulating in the warehouse and a rectifying diode. The rectifying diode is connected to an A.C. power source. A circuit formed by parallelly connecting the thermostat 41 and the antisweating heater 17 is interposingly connected between the rectifying diode and the A.C. power source.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low temperature chamber for cooling the inside of the chamber to a low temperature, and more particularly to a low temperature chamber capable of controlling the temperature inside the chamber from a freezing zone to a refrigerating zone.

[0002]

2. Description of the Related Art Conventionally, in this type of low temperature warehouse, in particular, in a low temperature open showcase where products are displayed and sold while being cooled, the inside of the refrigerator is kept at a low temperature during a cooling operation.
Moisture in the outside air is condensed and condensed around the cold air discharge port, the cold air suction port, the handrail, and the like. These dew drops cause inconveniences such as dripping on the product or wetting the customer's clothes. For example, Japanese Patent Laid-Open No. 5-141845 (F25D21 / 0) discloses such a dew point.
A dew-proof heater is provided as shown in 4).

This dew-proof heater is energized to generate heat during the cooling operation of the showcase and raises the temperature of the dew condensation-occurring portion to prevent condensation of moisture in the outside air.

[0004]

By the way, in recent years, the temperature inside the refrigerator is controlled from the freezing area to the refrigerating area so that a variety of products (frozen foods and refrigerated foods) can be displayed by using a single showcase. It is becoming possible. On the other hand,
The dew point temperature of the dew condensation occurrence point varies depending on the temperature inside the showcase. That is, when the temperature inside the refrigerator is used in the freezing zone, the temperature of the dew condensation occurrence point also becomes extremely low, so it is not possible to prevent the occurrence of dew condensation unless the heat generation amount of the dew condensation heater is increased, and conversely, When used in the refrigerating area, the calorific value may be small.

However, the heat generation amount of the dew-proof heater is usually set to be large so as to cope with the freezing area. Therefore, when it is used in a refrigerating area, wasteful power is consumed and the temperature of the dew condensation occurrence point rises too much, causing inconvenience such as customer burns.

Therefore, in the above publication, the heat generation amount of the dew-proof heater can be adjusted to an optimum value in accordance with various internal chamber temperatures.
A controller consisting of an inverter was provided, and adjustment was done by manually turning the dial, or automatically by a signal from a microcomputer for controlling the temperature inside the refrigerator.In the former case, however, the temperature range could be changed. Therefore, it is necessary to adjust the dial one by one, which is very troublesome, and there is a risk of forgetting to adjust the dial. Further, in the latter case, there is a problem that the electric circuit for controlling the showcase is largely changed (the program of the microcomputer and the output circuit wiring are changed), so that the cost is significantly increased.

The present invention has been made in order to solve the above-mentioned conventional technical problems, and it is a low-temperature warehouse in which the temperature inside the refrigerator can be controlled from the freezing zone to the refrigerating zone. It is an object of the present invention to enable the heat value of the heater to be adjusted to an optimum value.

[0008]

A low-temperature chamber according to the present invention comprises a dew-proof heater provided at a dew condensation-occurring location, a temperature control device for controlling the temperature inside the low-temperature chamber from a freezing zone to a refrigerating zone,
According to the temperature in the refrigerator or the temperature of the cold air circulating in the refrigerator, the contact is closed in the freezing area and the thermostat is opened in the refrigerating area, and a rectifying diode is provided, and the dew-proof heater is connected to an AC power source. A parallel circuit of a thermostat and a rectifying diode is connected between the dew-proof heater and an AC power source.

[0009]

According to the low temperature refrigerator of the present invention, when the temperature inside the refrigerator is set in the freezing region, the thermostat closes the contact depending on the temperature inside the refrigerator or the temperature of the cold air circulating in the refrigerator. It is short-circuited, and the full wave of AC power is applied to the dew-proof heater. Therefore, since the dew proof heater is 100% energized and the amount of heat generated is large, it is possible to reliably prevent dew condensation at a dew condensation occurring location.

On the other hand, when the temperature inside the refrigerator is set in the refrigerating region, the thermostat opens the contact, so that the half wave of the AC power source rectified by the rectifier diode is applied to the dew-proof heater. Therefore, the dew proof heater is energized by 50% and the amount of heat generated is halved, which saves energy and eliminates inconveniences such as burns to customers.

In particular, according to the present invention, since the thermostat automatically changes the heat generation amount of the dew-proof heater as described above, the operability is remarkably improved and the inconvenience of forgetting to change it is eliminated. It Further, since it is only necessary to insert the parallel circuit of the thermostat and the rectifying diode into the existing electric circuit, the design change can be simplified and the cost increase can be minimized.

[0012]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a vertical cross-sectional side view of an open showcase 1 as an embodiment of a cold storage of the present invention, and FIG. 2 is an electric circuit diagram of the open showcase 1. In FIG. 1, an open showcase 1 is a so-called flat open showcase that opens upward, and a bottom plate 3 and front and rear partition plates 4 and 4 are spaced apart from each other inside a heat insulating wall 2 having an opening on the upper surface. An inside 6 where the products are mounted and the products are displayed inside the bottom plate 3 and the partition plate 4.
And the duct 7 is formed outside.

A discharge port 8 and a suction port 9 are formed at the upper ends of the partition plates 4 and 4, respectively, and communicate with the duct 7.
Further, inside the duct 7 below the bottom plate 3, an evaporator 11 and a blower 12 for circulating cold air which constitute a well-known refrigeration cycle of a cooling device are installed. Furthermore, a handrail 14 made of stainless steel is attached to the opening edge of the heat insulating wall 2,
A wind direction plate 16 made of stainless steel is attached to the inside of the front and rear openings of the heat insulating wall 2 corresponding to above the discharge port 8 and the suction port 9.

A dew-proof heater 17, which is an electric heater, is provided inside (on the back side of) the handrail 14 and the wind direction plate 16 (where dew condensation occurs). It is assumed that the dew-proof heater 17 has a capacity capable of preventing dew condensation on the handrail 14 and the wind direction plate 16 even when the inside 6 is used in a freezing area in a heat generation state of 100%.

A machine room 21 is formed below the heat insulating wall 2, and a compressor 22, a condenser 23, a fan 24 for the condenser, and the like, which constitute a refrigeration cycle of the cooling device, are installed in the machine room 21. To be done.

Next, in FIG. 2, the compressor 22 is connected to an AC power supply AC in series with a temperature control device 31 including, for example, a thermistor and a comparator, and the blower 12 is also connected to the AC power supply AC. The dew-proof heater 17 has one end connected to the AC power supply AC, and a parallel circuit of a thermostat 41 and a rectifying diode 42 is connected in series between the other end and the AC power supply AC.

Here, the temperature control device 31 can set the temperature of the inside 6 from a freezing region such as -20 ° C to a refrigerating region such as + 5 ° C. Further, the compressor 22 is actually connected to a three-phase AC power supply, and the blower 12 and the dew-proof heater 17 are connected between the two phases of the three-phase power supply.

As shown in FIG. 1, the thermostat 41 is provided in the duct 7 on the upstream side (relative to the flow of cold air) of the discharge port 8 and opens and closes the contacts according to the temperature of the cold air discharged into the interior 6. To do. In this case, the thermostat 41 closes the contact when the temperature is lower than -5 ° C (refrigeration region),
If the temperature is -5 ℃ or higher (refrigerating area), the contact is opened.

On the other hand, the rectifying diode 42 is for half-wave rectifying the AC power supply AC. This rectifying diode 4
2 includes terminals 42A and 42B that linearly protrude from both ends, and one terminal 42A has a relatively long lead wire 5
One end of the lead wire 52 and one end of a relatively short lead wire 52 are fixed to the other terminal 42B by crimping, and the other ends of these lead wires 51 and 52 are connected to the electric circuit of FIG. A coupler 53 is attached. And FIG.
As shown in FIG.
2 and a part of the lead wires 51 and 52 are inserted, one end is sealed by high frequency welding, and the other end through which the lead wires 51 and 52 pass is also welded and sealed. According to this structure, the rectifying diode 42 is prevented from being flooded, and it is not necessary to bend the terminals 42A and 42B, so that the assembling work becomes extremely easy.

Next, the operation of the open showcase 1 having the above structure will be described with reference to FIG. For example, when the open showcase 1 is used as a freezing case, the temperature control device 31 is set to an internal temperature of, for example, −20 ° C. (freezing area). In this case, the temperature control device 31 is, for example,
Close the contact at the maximum temperature of 18 ℃. Temperature control device 3
When 1 closes the contacts, the compressor 22 is activated and the compressor 22
The high-temperature and high-pressure refrigerant discharged from the condenser is condensed in the condenser 23, decompressed by the decompression device (not shown), flows into the evaporator 11, and is evaporated. At this time, the evaporator 11 exerts a cooling action by removing latent heat from the surroundings.

The cool air that has been cooled by exchanging heat with the evaporator 11 is blown out to the right in FIG. 1 by the blower 12, rises in the duct 7, passes around the thermostat 41, and is discharged from the discharge port 8. It is discharged into the interior 6. The cool air that has circulated in the refrigerator 6 and cooled the products is sucked in through the suction port 9 and returns to the duct 7.

Due to such cooling, the temperature inside the refrigerator is, for example, −22.
When the temperature lowers to the lower limit temperature of ° C, the temperature control device 31 opens the contact, so that the compressor 22 is stopped. By this cooling operation, the inside 6 is maintained at a freezing temperature of -20 ° C on average.

On the other hand, as described above, the temperature inside the refrigerator is
Since it is set to a temperature range lower than 5, the duct 7
When the temperature of the discharge cold air (circulation cold air) passing around the inside of the thermostat 41 becomes lower than −5 ° C., the thermostat 41 closes the contacts as described above. As a result, the rectifying diode 42 is short-circuited, so that the full wave of the AC power supply AC is applied to the dew-proof heater 17. As a result, the dew-proof heater 17 becomes 100% energized (conductivity),
Generates a large amount of heat.

Since the inside temperature is set to the above-mentioned freezing region, the handrail 14 and the wind direction plate 16 are also strongly cooled, so that the moisture in the outside air easily condenses on their surfaces. As described above, the amount of heat generated by the dew proof heater 17 is automatically increased by the thermostat 41, so that dew condensation on the surfaces of the handrail 14 and the wind direction plate 16 can be reliably prevented.

On the other hand, when the open showcase 1 is used as a refrigerating case, the temperature control device 31 is set to an internal temperature of, for example, + 5 ° C. (refrigerating area). in this case,
The temperature control device 31 closes the contact at an upper limit temperature such as + 7 ° C. and opens the contact at a lower limit temperature such as + 3 ° C. As a result, the inside 6 is maintained at a refrigerating temperature of + 5 ° C. on average.

When the temperature inside the refrigerator is set in the refrigerating region (a temperature region of -5 or more) as described above, the temperature of the cold air passing around the thermostat 41 in the duct 7 becomes -5 ° C or more. As described above, the thermostat 41 opens the contact. As a result, a half wave of the AC power supply AC rectified by the rectifying diode 42 is applied to the dew-proof heater 17, so that the dew-proof heater 17 is 50% energized (duty factor) and the amount of heat generated is halved. To do.

Here, since the temperature inside the refrigerator is set to the above-mentioned refrigerating region, the handrail 14 and the wind direction plate 16 are also weakly cooled, so that dew condensation is prevented even if the heat generation amount of the dew-proof heater 17 is reduced. . On the other hand, since the amount of heat generated by the dew-proof heater 17 is halved, energy is saved and the temperature of the handrail 14 and the wind direction plate 16 does not become abnormally high, so that the customer who touches them is injured. Inconvenience is also eliminated.

In particular, according to the present invention, since the thermostat 41 automatically changes the heat generation amount as described above of the dew-proof heater 17, the operability is remarkably improved, and the inconvenience of forgetting to change is obviated. Will be resolved. Further, since it is only necessary to insert the parallel circuit of the thermostat 41 and the rectifying diode 42 into the existing electric circuit (FIG. 2), the design change can be simplified and the cost increase can be suppressed to the minimum.

In the embodiment, the thermostat 41 is provided in the duct 7 to detect the temperature of the cold air (discharging cold air) circulating in the interior 6. However, the thermostat 41 is not limited to this, and the thermostat 41 is installed in the interior 6. Alternatively, the temperature inside the refrigerator may be directly detected. Further, although the present invention is applied to the flat open showcase in the embodiments, the present invention is not limited to this, and the present invention is effective for refrigerators and other various low-temperature warehouses. Further, the various values shown in the embodiment are not limited to them,
Modifications can be made as appropriate without departing from the spirit of the present invention.

[0030]

As described in detail above, according to the present invention, when the temperature inside the refrigerator is set to the freezing zone, the thermostat closes the contacts according to the temperature inside the refrigerator or the temperature of the cold air circulating in the refrigerator. The rectifier diode is short-circuited, and the AC power source is directly applied to the dew-proof heater. Therefore, the amount of heat generated by the dew-proof heater increases, so that dew condensation on the dew-condensation occurrence place can be reliably prevented.

On the other hand, when the temperature inside the refrigerator is set in the refrigerating region, the thermostat opens the contacts, so that the dew-proof heater is applied with the AC power rectified by the rectifying diode. Therefore, the amount of heat generated by the dew-proof heater is reduced, which saves energy and eliminates the inconvenience that the customer is burned.

In particular, according to the present invention, since the thermostat automatically changes the heat generation amount of the dew-proof heater as described above, the operability is remarkably improved and the inconvenience of forgetting to change is eliminated. It Further, since it is only necessary to insert the parallel circuit of the thermostat and the rectifying diode into the existing electric circuit, the design change can be simplified and the cost increase can be minimized.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view of an open showcase as an embodiment of the present invention.

FIG. 2 is an electric circuit diagram of an open showcase as an embodiment of the present invention.

FIG. 3 is a front view of a rectifying diode.

FIG. 4 is a diagram showing an internal temperature and a duty ratio of a dew-proof heater.

[Explanation of symbols]

 1 Open showcase 6 Inside 7 Duct 11 Evaporator 14 Handrail 16 Wind vane 17 Dew-proof heater 41 Thermostat 42 Rectifier diode AC AC power supply

Claims (1)

[Claims] 1. A dew-proof heater provided at a dew condensation occurrence point of a low temperature warehouse, a temperature control device for controlling an internal temperature of the low temperature oven from a freezing zone to a refrigerating zone, and the internal temperature or the internal cabinet According to the temperature of the cold air that circulates, a thermostat that closes the contact in the freezing area and opens the contact in the refrigerating area,
A low temperature warehouse comprising a rectifier diode, wherein the dew-proof heater is connected to an AC power source, and a parallel circuit of the thermostat and the rectifier diode is connected between the dew-proof heater and the AC power source.