JP3462551B2 - Speed control device for blower for condenser - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blower for a condenser for air-cooling a condenser constituting a refrigeration cycle of an air conditioner / refrigeration apparatus such as an air conditioner and a low-temperature showcase. Related to the speed adjusting device. 2. Description of the Related Art Conventionally, in this type of air conditioning / refrigeration apparatus, a condenser of a refrigerating cycle is air-cooled by a blower for the condenser, and further based on the condensation temperature in the condenser. A speed control device for controlling the number of revolutions was provided. The speed control device can select a set high mode in which the condensing pressure is increased by switching the rotation speed characteristic of the blower for the condenser. That is, in the high mode in which the condensation pressure is increased, the rotation speed of the blower for the condenser is reduced from the stage where the condensation temperature of the refrigerant in the condenser is relatively high. Thereby, although the condensing pressure in the condenser becomes relatively high, the noise of the blower for the condenser can be suppressed to a low level, and it is suitable for the heat recovery operation. [0004] However, when the high speed mode is set in such a conventional speed control device, depending on the operating conditions, the condensing pressure after the compressor is started may rise and the blower for the condenser may not operate. In some cases, the increase in the number of revolutions could not follow. Such a state will be described with reference to FIG. In the figure,
The horizontal axis indicates the elapsed time T (s) from the start of the compressor, and the vertical axis indicates the condensing pressure HP (kg / square centimeter) in the condenser and the rotation rate (rotation speed) N (%) of the condenser blower. Although the condensing pressure HP rises sharply by the start of the compressor, the blower for the condenser is also started at the same time as the start of the compressor, the rotation rate N also increases, and the air cooling of the condenser is started. You. However, when the high mode is set, the rotation rate N of the condenser blower increases.
As shown by the broken line in the lower part of the figure, the cooling is slow, and the air cooling of the condenser is insufficient, so that the increase in the condensing pressure HP cannot be suppressed and reaches 30 kg after 30 seconds. At such a high pressure, there is a danger that an excessive load is applied to the compressor or the like, causing damage. Therefore, normally, the high pressure switch is operated and the compressor is abnormally stopped. Therefore, conventionally, a pressure switch that operates by detecting the condensing pressure of the condenser is added. For example, by operating the pressure switch at 21 kg, regardless of the high mode setting,
By operating the condenser blower at full speed (100%) as shown by the lower dashed line in the drawing, it was necessary to suppress the pressure rise to 22 kg before as shown by the upper dashed line in the drawing. SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional technical problems, and has been made to solve the above-mentioned problems. Therefore, it is possible to avoid an abnormal stop of the compressor without providing a special pressure switch. It is an object to provide a control device. [0008] The speed adjusting device 18 of the present invention.
Controls the number of revolutions of the condenser blower 11 for air-cooling the condenser 3 of the refrigeration cycle, which is formed by sequentially connecting the compressor 1, the condenser 3, the pressure reducing device (expansion valve) 7 and the evaporator 8 in a ring shape. there are a condensation temperature sensor 14 for detecting the temperature of the condenser 3, increase in the temperature detected in the condensation temperature sensor 14
So that the rotation speed of the condenser blower 11 increases
A control device 16 having a high rotation speed characteristic and controlling the rotation speed of the condenser blower 11 is provided.
Describes the rotational speed characteristics of the condenser blower 11 with a plurality of rotational speed characteristics.
The condensing pressure of the condenser 3 can be set by changing
When the condenser blower 11 is started in a state in which the mode is set to a mode in which the condensing pressure is increased , a mode switching switch for selectively switching the constant mode is provided. It controls the blower 11 for the condenser. [0009] Speed control device 1 of condenser blower 11 of the present invention
According to 8, when the condenser blower 11 is started in a state in which the mode is set to a mode in which the condensing pressure is increased, the condenser blower 11 is automatically operated at a rotation speed characteristic in which the condensing pressure is decreased for a predetermined period. Since the control is performed, regardless of the setting mode, the condenser 3 can be strongly air-cooled when the compressor 1 is started, and an abnormal increase in the condensing pressure can be prevented. Therefore, without providing an extraordinary pressure switch or the like, and irrespective of the set mode, the abnormal stop of the compressor 1 due to the abnormal increase of the condensing pressure can be avoided.
A stable cooling operation can be performed. Next, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a refrigerant circuit diagram of a refrigeration cycle to which the speed adjusting device 18 of the condenser blower 11 of the present invention is applied.
3A and 3B are diagrams respectively showing the rotational speed characteristics of the condenser blower 11 by the speed adjusting device 18 of the present invention. In FIG. 1, for example, a reciprocating, rotary or scroll type compressor 1
A pipe 4 constituting a condenser 3 is connected to a pipe 2 on the discharge side of the condenser 3. An outlet side of the pipe 4 of the condenser 3 is connected via a pipe 6 to an expansion valve 7 as a pressure reducing device. And
The outlet side of the expansion valve 7 is connected to an evaporator 8.
Is connected to a pipe 5 on the suction side of the compressor 1 to form an annular refrigeration cycle. The condenser 3 includes a plurality of heat exchange fins 9.
Is a fin tube type heat exchanger constructed by inserting the pipe 4 in a meandering shape, and a condenser blower 11 is provided corresponding to the condenser 3. The condenser blower 11 is for cooling the air by passing outside air through the condenser 3 and includes a motor 12 and a propeller fan 13. Reference numeral 18 denotes a speed controller of the present invention, which is constituted by a controller 16 comprising, for example, a general-purpose microcomputer. At the inlet side of the pipe 4 of the condenser 3, a condensing temperature sensor 14 of, for example, a thermistor constituting the speed adjusting device 18 is provided in a heat-exchange manner. Has been entered. The control device 16 of the speed adjusting device 18 controls the rotation speed of the motor 12 of the condenser blower 11 by a frequency modulation device such as an inverter. Further, the control device 16 has a high mode in which the condensation pressure HP of the refrigerant in the condenser 3 is high, a normal mode,
In addition, a mode change switch (not shown) for selecting and switching between three types of condensing pressure setting modes of a low mode, which is a low mode, is provided, and the control device 16 controls the condenser blower 11 (motor 12 ) Change the rotation speed characteristics. That is, the controller 16 controls the condensation temperature sensor 14
In the state where the high mode is set based on the output of the condenser blower, as shown by a solid line in FIG. 2, the range from the state where the refrigerant condensation temperature CT (° C.) in the condenser 3 is high to + 60 ° C. The rotation rate (rotation speed) N of 11 is 10
Full speed operation is performed with 0%, and control is performed to linearly decrease from 100% to 0% (stop) in the range from + 60 ° C to + 30 ° C. That is, since the condenser blower 11 is decelerated from the stage where the condensation temperature CT is higher, the refrigerant condensation pressure HP in the condenser 11 becomes relatively high. On the other hand, when the medium mode is set, the condensation temperature CT (° C.) as shown by the dashed line in FIG.
From high to + 50 ° C., for example, at full speed operation with the rotation rate (rotation speed) N of the condenser blower 11 as 100%, and linearly from 100% to 0% (stop) in the range from + 50 ° C. to + 20 ° C. The normal control for reducing the total is performed. On the other hand, in the state where the low mode is set, as shown by the broken line in FIG. 2, the range from the state where the condensation temperature CT (° C.) is high to + 40 ° C., for example, is the rotation rate (rotation speed) of the blower 11 for the condenser. Numeral) Full speed operation with N being 100%, and control to linearly decrease from 100% to 0% (stop) in the range of + 40 ° C to + 10 ° C. That is, until the condensing temperature CT becomes lower, the condenser blower 1
1 is operated at full speed, the condensing pressure HP of the refrigerant in the condenser 11 becomes relatively low. As described above, since the high mode and the low mode can be set in addition to the normal medium mode, the condenser blower 11 can be operated with low noise in the high mode, and the heat recovery operation can be performed. And the energy saving operation can be performed in the low mode. When the compressor 1 is started with the above configuration, the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 flows into the pipe 4 of the condenser 3 through the pipe 2. Outside air is passed through the condenser 3 from the condenser blower 11, where the refrigerant is air-cooled and condensed and liquefied. The refrigerant flowing out of the condenser 3 is supplied to a pipe 6
Through the expansion valve 7 where the pressure is reduced.
And evaporates there. The cooling effect is exerted by the endothermic effect at this time. Then, the refrigerant flowing out of the evaporator 8 is sucked into the compressor 1 from the pipe 5. A high-pressure switch (not shown) is provided on the discharge side of the compressor 1.
Operation is forcibly stopped, the pressure returns to the set value or less, and an operation of permitting the operation of the compressor 1 is performed. On the other hand, the control device 16 of the speed adjusting device 18 starts the motor 1 of the condenser blower 11 at the same time when the compressor 1 is started.
2 to start the air cooling of the condenser 3 and, based on the output of the condensing temperature sensor 14, according to the set mode (high mode, medium mode, low mode) in accordance with the rotation speed characteristic of FIG. The number of rotations of the condenser blower 11 is switched and controlled. However, the controller 1 of the speed controller 18
6 shows the state when the compressor 1 and the condenser blower 11 are started up.
The following control is executed. FIG. 4 shows a flowchart of a program of the control device 16 at the time of such startup.
That is, when the compressor 1 is started in step S1, the control device 16 determines whether or not the setting is the high mode in step S2, and proceeds to step S5 if the setting is the middle mode or the low mode. To start the condenser blower 11,
The condenser blower 11 is operated in the set mode. On the other hand, if the control device 16 is set to the high mode when the condenser blower 11 is started, the control device 16 proceeds from step S2 to step S3 to execute the condenser mode in the normal medium mode. The blower 11 is started and operated. Then, in step S4, it is determined whether, for example, 1 minute and 30 seconds have elapsed from the start, and the operation is performed in the middle mode until the elapse. Then, after the elapse, the process proceeds to step S5, and thereafter, the blower 1 for the condenser is set in the set high mode.
1 is driven. The transition of the rotation rate N of the condenser blower 11 from the start of the compressor 1 and the condenser blower 11 under such control is shown by the solid line in the lower part of FIG. 3, and the transition of the condensing pressure HP in the condenser 3 is shown in FIG. It is shown by a solid line at the top. As is clear from the figure, even when the high mode is set, the mode is automatically set to the middle mode when the condenser blower 11 is started, and the rotation rate N of the condenser blower 11 becomes higher. Thereby, the condenser 3 is strongly air-cooled,
An increase in the condensing pressure HP immediately after the start of the compressor 1 is suppressed,
An abnormal stop of the compressor 1 due to the high pressure switch is also avoided. In the embodiment, the operation mode of the condenser blower 11 at the time of startup when the high mode is set is set to the medium mode. However, the present invention is not limited to this. Things to change (eg low mode)
If so, it does not matter. Further, each value in the embodiment is not limited thereto, and can be variously changed according to the device capability and the like. As described above in detail, according to the present invention, if the blower for the condenser is started in the mode in which the condensing pressure is set to be high, the condensing pressure is automatically set for a predetermined period. Since the blower for the condenser is controlled based on the rotation speed characteristic at which the pressure becomes low, the condenser can be strongly air-cooled when the compressor is started, regardless of the setting mode, and an abnormal increase in the condensation pressure can be prevented. Therefore, without providing a special pressure switch or the like, and irrespective of the set mode, the abnormal stop of the compressor due to the abnormal rise of the condensing pressure can be avoided beforehand, and the stable cooling operation can be performed. Is what you can do.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a refrigerant circuit diagram of a refrigeration cycle to which a speed control device for a blower for a condenser according to the present invention is applied. FIG. 2 is a diagram showing a rotation speed characteristic of a blower for a condenser by the speed control device of the present invention. FIG. 3 is a graph showing changes in the condensing pressure and the rotation rate of the condenser blower with respect to the elapsed time from the start of the compressor. FIG. 4 is a flowchart showing a program of a control device of a speed control device for a blower for a condenser according to the present invention. [Description of Signs] 1 Compressor 3 Condenser 7 Expansion valve 8 Evaporator 11 Blower for condenser 14 Condensation temperature sensor 16 Control device 18 Speed control device

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F25B 1/00 381

Claims (1)

(57) [Claim 1] A speed adjusting device for a blower for a condenser for air-cooling the condenser of a refrigeration cycle in which a compressor, a condenser, a pressure reducing device, and an evaporator are sequentially connected in a ring shape. A condenser temperature sensor for detecting the temperature of the condenser, and a blower for the condenser in accordance with an increase in the temperature detected by the condenser temperature sensor.
A control device for controlling the rotation speed of the condenser blower having a rotation speed characteristic such that the rotation speed of the condenser increases . The control device controls the rotation speed characteristic of the condenser blower for a plurality of times.
By changing the speed characteristics, the condenser
Set the mode switch to select and switch the compression pressure setting mode.
A, wherein when the condenser blower in a state in which the condensing pressure is set to becomes higher mode is activated, the controller controls the condenser blower at a rotation speed characteristic of a predetermined period condensing pressure is low Characteristic speed control device for condenser blower.