JPH0611236A - Airflow control structure for open show case - Google Patents

Abstract

PURPOSE:To provide an airflow control structure for open show case which can prevent the air velocity of air-curtain from decreasing by increasing the airflow at the time of a one-side operation. CONSTITUTION:When a proximity switch 14 is turned on, i.e., under a second operation mode, the number of revolutions of a blower 8 is set to be smaller. Also, the proximity switch 14 is turned off, i.e., under first and third operation modes, the number of revolutions of the blower 8 is set to be larger. By doing this, the air velocity of an inside air-curtain A2 which is formed at the opening on the front surface is prevented from decreasing, and the outside air can be prevented from entering at the time of the first and third operation modes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an open-circuit system for always cooling the inside of a refrigerator by setting the other cold air passage as a cooling mode when one of the cold air passages is in the defrosting mode. -It relates to the structure for controlling the air flow rate.

[0002]

2. Description of the Related Art Conventionally, the applicant has already proposed an open case of this kind disclosed in Japanese Utility Model Laid-Open No. 61-101375.

The open-case has a product storage chamber having a front opening, and two cold air passages are formed outside the product storage chamber. An evaporator is arranged in each of the cold air passages. Has been done. While each cold air passage is ventilated by a blower, one or the other cold air passage is opened by a damper of the passage opening / closing means, or both cold air passages are opened so that an air curtain is provided at the front opening of the product storage chamber. Is formed.

[0004]

However, since the air volume of the blower is constant, when only one or the other cold air passage is opened by the damper (one-side operation), both the cold air passages are opened to ventilate the air. Comparing the cases (operation on both sides), the one-sided operation has a half of the passage cross-sectional area, and therefore the ventilation resistance is increased accordingly.

As a result, in one-sided operation, the wind velocity of the air curtain formed at the front opening decreases due to an increase in ventilation resistance, and there is a problem in that outside air enters the storage compartment. .

In view of the above conventional problems, an object of the present invention is to
An object of the present invention is to provide an air flow rate control structure for an open casing, which can increase the air flow rate during one-sided operation and prevent a decrease in the air velocity of the air curtain.

[0007]

In order to solve the above-mentioned problems, the present invention forms an air cart at the front opening of a product storage chamber by two cold air passages in which evaporators are respectively arranged, and the respective cold air passages are formed. The ventilation of the blower passing therethrough is switched by the passage opening / closing means, and the evaporator in one cold air passage is cooled by the cooling mode.
Mode in which the evaporator in the other cold air passage serves as the defrosting mode, a second operation mode in which the evaporator in both cold air passages serves as the cooling mode, and the other cold air The evaporator in the passage is used as a cooling mode and the evaporator in one of the cold air passages is used as a defrosting mode.
In an air flow rate control structure for an open case having an operation mode, the air flow rate of the air blower in the second operation mode is adjusted to the air flow rate of the air blower in the first and third operation modes. It is characterized by having an air volume control means for increasing the air volume.

[0008]

According to the present invention, since the air volume in the first and third operation modes is larger than that in the second operation mode, the wind speed decreases with an increase in ventilation resistance in one-side operation. Is compensated by this increase in the air volume, and a predetermined wind speed of the air curtain can be obtained.

[0009]

1 to 5 show an opening according to the present invention.
FIG. 1 is a sectional view of an open case, showing an embodiment of a structure for controlling the air volume of the case.

In the figure, 1 is a case main body formed of a heat insulating wall in a substantially U-shaped cross section, 2 is a product storage room with a front opening arranged in the case main body 1, and 3 is a case. It is an air passage formed between the main body 1 and the product storage chamber 2. The air passage 3 has an outer air passage 4 and an inner air passage 5, and air is passed through the outer air passage 4 as indicated by an alternate long and short dash line in FIG. It forms Ten A ₁ .
The inner air passage 5 is divided into front and rear by a partition plate 6, and the first evaporator 7a is provided above the cold air passage 5a inside the inner air passage 5.
The second evaporator 7b is arranged in the lower part of the outer cool air passage 5b, and the air cooled by the cold air passages 5a and 5b is blown by the blower 8 into the product storage chamber 2 as shown by solid line arrows in the figure. The air is blown to the front opening 2a, and the inner air curtain A ₂ is formed in the front opening 2a.

Each evaporator 7a, 7b arranged in this way
Is a component of the cooling device, and the configuration of the cooling device will be described with reference to the refrigerant circuit diagram of FIG.

That is, this cooling device includes a compressor 9, a condenser 10, solenoid valves 11a to 11e, expansion valves 12a and 12b,
The check valves 13a to 13d are connected by piping.

Here, the first operation mode, that is, the first evaporator 7
When performing the defrosting operation on a and the cooling operation on the second evaporator 7b,
Each solenoid valve 11a, 11e is opened and each solenoid valve 11b, 1e
1c and 11d are closed, and the refrigerant discharged from the compressor 9 is indicated by a solid arrow, and the condenser 10 → the solenoid valve 11a → the first
Evaporator 7a → Check valve 13c → Check valve 13b → Expansion valve 12
It is circulated in the order of b → second evaporator 7b → solenoid valve 11e → compressor 9.

The second operating mode, that is, the first and second evaporators 7
When cooling both a and 7b, each solenoid valve 11
b, 11d, 11e are opened, and each solenoid valve 11a, 11c
And the refrigerant discharged from the compressor 9 is closed as shown by the one-dot chain line arrow, condenser 10 → solenoid valve 11b → check valve 13a.
(13b) → expansion valve 12a (12b) → evaporator 7a (7
b) → solenoid valve 11d (11e) → compressor 9 is sequentially circulated.

Further, the third operation mode, that is, the second evaporator 7b.
When the defrosting operation is performed and the first evaporator 7a is cooled, the solenoid valves 11c and 11d are opened and the solenoid valves 11a and 11d are opened.
b and 11e are closed, and the refrigerant discharged from the compressor 9 is shown by the double-dashed line arrow, as shown by a condenser 10 → a solenoid valve 11c → a second evaporator 7b → a check valve 13d → a check valve 13a → an expansion valve. 1
2a-> first evaporator 7a-> solenoid valve 11d-> compressor 9 are sequentially circulated.

The respective operation modes are the first operation mode, the second operation mode, the third operation mode, the second operation mode, and the first operation mode.
By sequentially repeating the operation mode, one side operation on one side, both sides operation and one side operation on the other side are performed.

In order to prevent warm air generated in the evaporator on the defrosting side from flowing into the product storage chamber 2 in each operation mode as described above, a rotary damper 14 which is a passage opening / closing means as shown in FIG. Is provided. The damper 14 is installed above the partition plate 6, and the installation state of the damper 14 is shown in FIG. That is, the damper 14 is the motor box 1.
The motor 5 is rotated by a motor (not shown) installed in the air conditioner 5, and as shown in FIG.
The second operation mode is set with both a and 5b open, and the third operation mode is set with the left side position, that is, the cold air passage 7b closed and the cold air passage 7a open.
Further, the right side position, that is, the cold air passage 7a is closed, and the cold air passage 7b is closed.
The first operation mode is set in a state in which is open.

Further, an iron plate 16 which is a magnetic material is fixed to one end of the damper 14 in the longitudinal direction, and is opposed to the upper surface of the motor box 15 at an intermediate position of the damper 14 so that the second operation motor is operated.
An inductive bridge type proximity switch 17 for detecting a switch is installed.

FIG. 4 shows the blower 8 in each operation mode.
The μCPU 18 having a microcomputer configuration controls a blower drive circuit 19 having an inverter circuit based on a detection signal from the proximity switch 17 to control the rotation speed of the blower 8. .

FIG. 5 shows a flow chart of this drive control circuit. When the proximity switch 17 is turned on, that is, in the second operation mode, for example, the rotation speed of the blower 8 is set to N ₁ (13).
00 rpm) (S1, S2), and when the proximity switch 17 is turned off, that is, in the first and third operation modes, for example, the rotation speed of the blower 8 is N ₂ (1500 rp).
m) is set (S1, S3).

As described above, according to the present embodiment, the ventilation resistance of the inner air passage 5 is increased by closing one of the dampers of the cold air passage 5a or the cold air passage 5b, but in the first and third operation modes. because it has increased the number of revolutions of the blower 8, the inner Eaka the front opening 2a - wind speed Ten a ₂ is prevented from lowering, the first and third operating mode - it can be prevented from entering of outside air at the time of de.

6 and 7 show another embodiment of the present invention. FIG. 6 is a block diagram showing a drive control circuit of the blower 8, and FIG. 7 is a flow chart of this drive control circuit. .
In the above embodiment, the number of revolutions of one blower 8 is increased / decreased by the inverter circuit, but in this embodiment, two blowers 8 are installed and the blower drive circuit 20 controls the number of blowers.

As shown in the flow chart of FIG. 7, when the proximity switch 17 is turned on, that is, in the second operation mode, one blower 8 is driven (S, S), and When the proximity switch 17 is turned off, that is, in the first and third operation modes, the two blowers 8 are driven (S, S).
).

As described above, according to this embodiment, the control of the number of the blowers 8 prevents the wind speed of the inner air curtain A ₂ from decreasing. The rest of the configuration and operation are the same as in the above embodiment.

[0025]

As described above, according to the present invention,
Since the air volume in the first and third operation modes is larger than the air volume in the second operation mode, the decrease in the wind speed due to the increase in the ventilation resistance in the one-side operation is compensated by this increase in the air volume. It is possible to obtain a predetermined wind speed of the air curtain. Therefore, the outside air does not enter the product storage chamber, and it is possible to prevent the internal temperature from rising.

[Brief description of drawings]

FIG. 1 is a sectional view of an open case.

FIG. 2 is a refrigerant circuit diagram of a cooling device.

FIG. 3 is a perspective view showing an installed state of the damper.

FIG. 4 is a block diagram showing an embodiment of a drive control circuit of a blower.

FIG. 5 is a flow chart of an embodiment of a drive control circuit of a blower.
Chart

FIG. 6 is a block diagram showing another embodiment of the drive control circuit of the blower.

FIG. 7 is a flowchart according to another embodiment of the drive control circuit of the blower.

[Explanation of symbols]

1 ... Case main body, 2 ... Product storage room, 2a ... Front opening, 5
a, 5b ... Cold air passage, 7a, 7b ... Evaporator, 8 ... Blower, 14 ... Damper, 17 ... Proximity switch, 18 ... μCP
U, 19, 20 ... fan driving circuit, A _1, A ₂ ... Eaka - Ten.

Claims (1)

[Claims] 1. An air cart is formed at the front opening of a product storage chamber by two cold air passages each having an evaporator, and ventilation of a blower passing through each cold air passage is switched by passage opening / closing means to provide one cold air passage. A first operation mode in which the evaporator in the passage is a cooling mode and the evaporator in the other cold air passage is a defrosting mode, and a second operation is in which the evaporators in both cold air passages are a cooling mode. And a third operation mode in which the evaporator in the other cool air passage is the cooling mode and the evaporator in the one cool air passage is the defrosting mode. The air volume control structure has an air volume control means for increasing the air volume of the blower in the first and third operation modes more than the air volume of the blower in the second operation mode. -Punsho-case air volume control structure.