JPH02275256A - Air blower control device of freezer - 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] [Object of the Invention] (Industrial Application Field) This invention relates to a refrigerator used in a refrigerator showcase, a refrigerator, etc. ! <Conventional technology regarding I machine control device> This type of refrigerator is mainly used in commercial refrigeration machines such as large refrigerators, refrigerator showcases, and refrigeration equipment. It is equipped with

As shown in FIG. 5, this split-type refrigerating vessel has a compressor 2, a condenser 3, and a feeder J! in an outdoor unit 1-1. A thermostat 6 for a fan controller is attached to a heat transfer vibrator 5 located after the middle part of the capacitor 3. This thermostat]・
6 detects the temperature of the refrigerant and controls the operation of the blower 4 to ensure the condensation pressure of the refrigerant commensurate with the outside temperature.

(Problem to be Solved by the Invention) In the conventional refrigerator, only one thermostat 6 is attached as a temperature sensor after the middle part of the condenser 3, so the transmission J! 14
When the fan motor 7 is driven from a stopped state, a temperature difference occurs between the actual condensation temperature of the refrigerant and the temperature detected by the heat-sensitive tube of the mostat 6 due to a heat transfer delay. Due to this, the operation time of the blower 4 is delayed.

For this reason, the condensation pressure of the refrigerant becomes high and exceeds the allowable amount, which may cause the high pressure switch to malfunction (see FIG. 6).

If the high pressure switch malfunctions, the drive of the compressor 2 will be stopped, which may impair the function of the refrigerator.Also, once the compressor 2 has stopped, it may not be possible to restart it for a predetermined period of time, or you may have to restart it manually. This had to be done each time, which was troublesome and caused a decrease in the reliability of the refrigerator.

From this point of view, it is conceivable to install a heat-sensitive tube of the thermostat 6 near the inlet of the compressor 2 to reduce the adverse effects caused by the delay in heat transfer. The temperature and pressure characteristics of the refrigerant are unstable, and this poses a practical problem.

Additionally, as a measure to prevent high-pressure cuts to prevent the compressor from stopping due to high-pressure switch activation, it is possible to install a pressure switch that operates at a -stage lower refrigerant pressure value and use this pressure switch to check the operation of the fan motor of the blower. In this case, there is a risk of refrigerant being released during maintenance of the pressure switch, making it economically and environmentally unsuitable for controlling the operation of a blower.

This invention was made in consideration of the above-mentioned circumstances,
The purpose of the present invention is to provide a blower control device for a refrigerator that prevents an increase in refrigerant condensation pressure due to a delay in the operation of a temperature sensor during a transient period, prevents malfunction of a pressure switch in advance, and improves reliability. shall be.

[Structure of the invention]

(Means for Solving the Problems) A blower control device for a refrigerator according to the present invention has the following features:
In a refrigerator equipped with a condenser, a blower, etc., temperature sensors for detecting refrigerant temperature are provided near the inlet of the condenser and on the outlet side after the intermediate part thereof, and temperature signals detected by both of the wetness sensors are inputted. (The 1 m section is equipped with temperature correction means for controlling the operation of the blower.

(Function) This refrigerator blower control device is equipped with temperature sensors for detecting refrigerant temperature near the inlet of the condenser and on the outlet side after the intermediate section, and controls the refrigerant temperature detected by both temperature sensors. Since the operation of the blower is controlled by making corrections using the temperature correction means of the control unit based on the temperature difference, it is possible to eliminate or reduce the operation delay of the temperature sensor during the transition period, and to reduce the refrigerant flow due to the operation delay. Prevents condensation pressure from rising and prevents pressure switch malfunctions.
The reliability of the refrigerator can be improved.

(Example) Hereinafter, an example of the arrangement of a blower 11J for a refrigerator according to the present invention will be described with reference to the accompanying drawings.

Fig. 1 does not show the outdoor unit 1 of a split type refrigerator that is suitably used for refrigerators, freezer showcases, refrigeration equipment, etc. In this outdoor unit 10, a compressor 11, a condenser 12, and an air blower are installed. 13 etc. will be accommodated. The outdoor unit 10 has a packed valve 14
It is connected to the indoor side of the refrigerator via a and 14b, and constitutes a refrigeration cycle 15.

On the other hand, thermostats 17 and 18 are respectively provided as temperature sensors for detecting refrigerant temperature on the heat transfer pipe 16 near the entrance of the condenser 12 and on the exit side after the middle part, and both thermostats 17 and 18 are composed of a thermistor or the like, Send J
A control unit 20 that controls the operation of the fan motor 19 of the il 13
The temperature signals detected by both thermostats 17 and 18 are input to the control section 20, respectively. The control section 20 is composed of a CPU such as a microcomputer, and includes a temperature correction means 20a that controls the operation of the fan motor 19 of the blower 13 based on the detected temperature difference.

The temperature correction means 20a of the control unit 20 has both thermostats 1
7. Compare and calculate the detected temperature signal input from 18,
As shown in FIGS. 2 and 3, the temperature difference Δt
When the value is greater than a specified value, a drive control relay (not shown) for the fin motor 9 is operated. The specific calculation and control of the temperature correction means 20a of the control unit 20 is such that the temperature difference Δt between the inlet side thermostat 17 and the outlet side thermostat 18 is a reference specified value Δt, for example, 10
As shown in Fig. 3, when the temperature exceeds the normal setting, the fan control operation value (7 motor ON value) of feed J[13] is moved from the normal setting tsl to the setting value ts2 (<tsl). The OFF value of the fan motor 19 is set so that it remains the same even when moving from the set value tsl to ts2.In Fig. 2, the broken line indicates the detected temperature curve of the inlet side thermostat 17, and the solid line B indicates the detected temperature curve Detection temperature curves of the outlet side nermostat 18 are shown.
The symbol Pd is a temperature-converted pressure curve of the refrigerant.

Conversely, when the temperature difference Δt between the inlet side thermostat 17 and the outlet side thermostat 18 becomes less than another standard set value Δt1, for example, 5 degrees, the fan control operation value is returned from the set value t to tsl. It has become.

In addition, the thermostat 1 attached to the capacitor 12
-17 and 18 are ideally attached to attachment areas C and D shown in FIG.

Fig. 4 shows a Mollier diagram of the refrigeration cycle 15, where the solid line E represents the refrigeration cycle when the refrigerator is operating with an overload (summer S), and the chain line F represents the refrigeration cycle when the refrigerator is operating with a low load (winter). Each cycle is shown below. As shown in this Mollier diagram, the inlet thermostat 17 is located slightly above the saturated gas line G toward the saturated region (wet gas), and the outlet thermostat 18 is located slightly toward the saturated region (wet gas) from above the saturated liquid line H. Can be installed conveniently. The main control thermostat that controls the fan of the blower 13 is, for example, an outlet-side thermostat.

Next, the operation of the blower control device for the refrigeration machine will be explained.

This blower control device includes a temperature correction means 20 in the control section 20.
a, and with this temperature correction means 20a, the capacitor 12
The refrigerant temperature near the inlet and the refrigeration temperature from the intermediate section to the outlet side are detected by both thermostats 17 and 18, respectively, and the fan control operating value t of the air blower 1113 is corrected based on the temperature difference.

The operation of this refrigerator is started by starting the compressor 11, and the refrigerant compressed by the compressor 11 is guided into the refrigeration cycle 15 and circulated. However, the temperature of the refrigerant flowing in the refrigeration cycle 15 cannot be expressed on the Mollier diagram shown in FIG. can be seen. Since the refrigerant in the capacitor 12 is in the superheated gas region during the transition period, the cold ts temperature rise at this time is higher than the saturation 4 degrees equivalent of the refrigerant pressure during the transition period.

During this transition period, the refrigerant temperature sensed by the outlet side thermostat 18 is delayed in temperature rise due to heat capacity. In order to prevent an adverse effect due to a delay in the operation of the thermostat 18, which is a temperature sensor during a transitional period, and to prevent a high pressure cut, the control unit 20 is equipped with a temperature correction means 20a, and this temperature correction means 20a is provided with a temperature correction means 20a. temperature difference Δ
t is calculated, and this temperature difference Δt is the M semi-set value Δt1,
For example, if the temperature exceeds 10 degrees, set the fan control operation value 13 (fan motor ON value) to the normal setting &r1t
Kara MQ constant (UtS2 (<t,) lowered to "'C1C
The operation delay (time delay) of the first sidetone nermostat 18 is shortened.

When the operating state of the refrigerator shifts from a transient period to a stable state, the refrigerant temperature detected by the inlet side thermostat 17 approaches the condensing pressure conversion value, and the refrigerant temperature detected by the outlet side thermostat 18 also follows. , both thermostats 17.
The temperature difference Δt detected by 18 becomes smaller, and this temperature difference Δt
When t is less than another reference setting value Δt, for example about 5 degrees,
The temperature correction means 20a of the control unit 20 estimates that it is in a safe operating state, and the fan control operating value tS ()
? (motor ON value) is returned from the set value ts2 to tsl. At that time, the fan motor 0FFrf1t.

is constant, the blower 13 has a fan motor 9 of 0.
Stable operation can be guaranteed without repeating N10FF, and reliability of the refrigerator can be improved.

In one embodiment of the present invention, no particular consideration is given to the heat capacity a of the inlet-side and outlet-side thermostats; The mounting positions of both thermostats may be moved close to each other to improve the mounting workability.

〔Effect of the invention〕

As described above, in the blower control device for a refrigerator according to the present invention, humidity sensors for detecting refrigerant temperature are provided near the inlet of the condenser and on the outlet side after the intermediate part thereof, and the detected temperature signals of both temperature sensors are input to the control unit,
Since a temperature correction means is provided to correct the temperature difference at this point and control the operation of the blower, it is possible to absorb the operation delay of the temperature sensor during the transition period, and to reduce the operation delay of the temperature sensor, the pressure switch It is possible to prevent malfunctions and improve the reliability of the refrigerator.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an embodiment of a refrigerating machine feed unit control fll device according to the present invention, FIG. 2 is a diagram showing temporal changes in refrigerant temperature in a condenser detected by a thermostat, and FIG. 4 is a Mollier diagram of the refrigeration cycle incorporated in the refrigerator, and FIG. 5 is a diagram showing the chamber of a conventional refrigerator. Diagram showing the outer unit,
Diagram M6 is a diagram showing a comparison between the refrigerant temperature detected by the thermostat and the actual cold Is condensation temperature. 10... Outdoor unit I, 11... Compressor, 12... Condenser, 13... Air blower □, 15...
・Refrigerating cycle, 16...Heat transfer pipe, 17.18・
...Thermostat (temperature sensor), 20...Control unit, 20a...Temperature correction means. Hat part? Diagram (enthalpy) Necessary diagram Ginma diagram

Claims (1)

[Claims] In a refrigerator equipped with a compressor, a condenser, a blower, etc., temperature sensors for detecting the refrigerant temperature are provided near the inlet of the condenser and on the outlet side after the intermediate part thereof, and temperature signals detected by the two temperature sensors are inputted. A blower control device for a refrigerator, characterized in that a control section includes a temperature correction means for controlling operation of the blower.