JPH07218059A - Air conditioner provided with reverse rotation-preventing function - Google Patents

Abstract

PURPOSE:To detect reverse rotation of a compressor regardless of applying voltage to the compressor, so as to effectively enable prevention of reversal rotation of the compressor by detecting pressure of a refrigerating cycle in an air conditioner using a rotary compressor wherein the rotating and compressing direction is determined. CONSTITUTION:High-temperature/high-pressure refrigerant discharged from a compressor l passes a chuck value 2 and heat-exchanged from cooling water by a condenser 3 into high-pressure liquid refrigerant, and the liquid refrigerant is supplied to an evaporator 5 after being depressurized by an expansion valve 4. And it is heat- exchanged from cooling water into low-temperature/low-pressure gas refrigerant and then returned to the compressor 1. In this case, a pressure detecting port 6 is arranged on a discharge part of the compressor 1, and a pressure detecting port 7 is arranged on an inlet port, so as to detect pressure of the refrigerating cycle. When the compressor is reversely rotated, discharge pressure is decreased, and inlet pressure is increased after the compressor ms started, and differential pressure between both sides is decreased, thereby reverse rotation of the compressor is detected on the basis of the detected result of the pressure, and the operation is so controlled as to be stopped.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner using a rotary compressor having a fixed rotary compression direction, and a discharge pressure Pd from a pressure detection port provided at a discharge part or a suction part of the compressor. Alternatively, either one of the suction pressure Ps is detected, and the condition change is made by using the pressure change rate from the time when the compressor is stopped to the specified time after starting, that is, the direction of rotation of the compressor is detected depending on the pressure state of the refrigeration cycle and the reverse. A device for preventing rotation.

[0002]

2. Description of the Related Art An air conditioner using a conventional rotary compressor whose rotary compression direction is fixed has a three-phase power supply which is supplied to the compressor by attaching a negative phase relay to a three-phase power supply which is supplied to the compressor. The reverse rotation of the compressor is detected by determining whether each phase is a positive phase. Further, in Japanese Patent Application Laid-Open No. 54-154810, when the pressure after starting the compressor becomes higher than the discharge pressure, the suction pressure is judged to be the reverse rotation of the compressor, and the compressor is stopped.

[0003]

In an air conditioner using a rotary compressor whose rotary compression direction is fixed, whether each phase of a three-phase power source to be supplied to the compressor is positive or negative by a reverse phase relay. It was judged that it was preventing the compressor from rotating in the reverse direction. This method cannot detect the reverse rotation of the compressor because there is no reverse-phase relay that can be used in the refrigeration system with high voltage specifications of 3KV and 6KV.

An object of the present invention is to prevent reverse rotation of a compressor by detecting the pressure of a refrigeration cycle in an air conditioner using a rotary compressor whose rotational compression direction is fixed, and to put the compressor into the compressor. It is possible to detect the reverse rotation of the compressor regardless of the voltage of the three-phase power supply.

[0005]

In order to achieve the above object, the present invention relates to an air conditioner using a rotary compressor having a fixed rotary compression direction, which is provided in either the compressor discharge part or the suction part. When the discharge pressure Pd or the suction pressure Ps is detected from the provided pressure detection port in a specified time from the time the compressor is stopped to the time it is started, and the pressure change rate detects the discharge pressure Pd, When the pressure change rate is negative,
When the suction pressure Ps is detected, when the rate of pressure change is positive, the compressor is stopped to prevent reverse rotation of the compressor.

[0006]

[Action]

(1) In an air conditioner using a rotary compressor with a fixed rotary compression direction, a pressure difference ΔP = between the discharge pressure Pd and the suction pressure Ps is obtained from pressure detection ports respectively provided in the discharge part and the suction part of the compressor. Detecting Pd-Ps, comparing the pressure difference ΔP ₁ when the compressor is stopped with the pressure difference ΔP ₂ immediately after starting,
When P ₁ > ΔP ₂ , the compressor is stopped and reverse rotation of the compressor is prevented.

(2) In an air conditioner using a rotary compressor whose rotational compression direction is fixed, the discharge pressure Pd is detected from a pressure detection port provided in the discharge part of the compressor, and the compressor is started when the compressor is stopped. At a later specified time Δt, the pressure change rate ΔP of the discharge pressure is used, and when ΔP / Δt <0, the compressor is stopped and reverse rotation of the compressor is prevented.

(3) In an air conditioner using a rotary compressor having a fixed rotary compression direction, the suction pressure Ps is detected from a pressure detection port provided in the suction portion of the compressor, and the compressor is started when the compressor is stopped. At a later specified time Δt, the pressure change rate ΔP of the suction pressure is used, and when ΔP / Δt> 0, the compressor is stopped and reverse rotation of the compressor is prevented.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a refrigeration cycle system diagram of an air conditioner using a rotary compressor having a fixed rotary compression direction according to the present invention. The high temperature / high pressure gas refrigerant compressed by the compressor 1 passes through the check valve 2 and exchanges heat with the cooling water in the condenser 3 to become a high pressure liquid refrigerant. The high-pressure liquid refrigerant is decompressed by the expansion valve 4, exchanges heat with cold water in the evaporator 5, becomes low-temperature low-pressure gas refrigerant, and returns to the compressor 1 in the refrigeration cycle. In the present invention,
A pressure detection port 6 is provided at the discharge part of the compressor 1 and a pressure detection port 7 is provided at the suction part, and a reverse rotation prevention function is detected by detecting the reverse rotation of the compressor by detecting the pressure of the refrigeration cycle and stopping the operation. It is a refrigerating device provided.

A compressor reverse rotation detection method will be described with reference to FIG. FIG. 2 shows the discharge pressure Pd, the suction pressure Ps, and the pressure differences ΔP ₁ to ₃ detected by the pressure detection port 6 and the pressure detection port 7 in FIG. ₁ . When the compressor is rotating normally, the discharge pressure Pd after starting the compressor increases, the suction pressure Ps decreases, and the pressure difference ΔP ₃ increases. On the other hand, if the compressor is rotating in reverse,
After the compressor is started, the discharge pressure Pd decreases, and the suction pressure Ps increases and the pressure difference ΔP ₂ decreases. This result shows that the states of the discharge pressure Pd and the suction pressure Ps when the compressor is stopped are Pd> Ps and Pd.
The same applies in all cases of = Ps and Pd <Ps. As described above, in the present invention, the pressure difference immediately after the start of the compressor 1 is compared with the pressure difference immediately after the start of the compressor 1, for example, 0 to 5 seconds, and the pressure difference immediately after the start of the compressor 1 is small. At this time, the compressor 1 is stopped.

Further, as an application of the embodiment, the pressure detection port 6 is provided only in the discharge part of the compressor 1 of FIG. 1, and the discharge pressure detected from this detection port is detected from the start of the compressor 1 to the compressor 1.
When the pressure change rate ΔP of the designated time Δt (for example, 0 to 5 seconds) after the startup of is used, and when ΔP / Δt <0, the compressor 1 is stopped.

Similarly, when only the suction pressure is detected, the pressure detection port 7 is provided only in the suction portion of the compressor 1 shown in FIG. , A specified time Δt after the compressor 1 is started (for example, 0
The pressure change rate ΔP for ˜5 seconds) is used, and when ΔP / Δt> 0, the compressor 1 is stopped. In addition, in this control, it is impossible to compare the pressure difference when the compressor is stopped with the pressure difference immediately after the compressor is started and to use a differential pressure switch to detect the reverse rotation of the compressor, and to perform control.

FIG. 3 shows the reverse rotation detection control of the power supply circuit unit and compressor of the present invention. When the compressor 1 stops under the pressure difference ΔP = Pd−Ps between the discharge pressure Pd and the suction pressure Ps detected from the high pressure detection port 17a and the low pressure detection port 17b, the relay coil 9 is fed from the control board 8
Is energized, the relay contact 9a arranged in the upstream portion of the electromagnetic contactor 10 is opened, and the electromagnetic contactor 10 is de-energized. Therefore, the electromagnetic contactor contact 10a is opened, the electric motor 14 of the compressor 1 is de-energized, and the compressor 1 is stopped.

FIG. 4 shows the conventional reverse rotation detection control of the power supply circuit section and the compressor. This control determines whether or not the three-phase power supplied to the electric motor 14 by the negative-phase relay 18 is a positive phase for each phase. When it is not in the positive phase, the negative phase relay contact 18a is opened and the electromagnetic contactor 10 is de-energized. Therefore, the electromagnetic contactor contact 10a is opened, the electric motor 14 is de-energized, and the compressor 1 is stopped. With this control, in the case of high voltage specifications of 3KV and 6KV, there is no reverse-phase relay that can be used, so high voltage specifications cannot be supported.

[0015]

According to the present invention, in an air conditioner using a rotary compressor whose rotary compression direction is fixed, either the compressor discharge part or the suction part of the refrigeration cycle is used regardless of the power supply voltage used. The reverse rotation of the compressor can be prevented by conditionally determining the discharge pressure or the suction pressure detected from the provided pressure detection port with respect to the pressure change rate in the designated time from the stop of the compressor to the start of the compressor.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a refrigeration cycle system of an air conditioner according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of an embodiment of the present invention and a method for detecting reverse rotation of a compressor.

FIG. 3 is an explanatory diagram of an embodiment of the present invention, a power supply circuit section, and a reverse rotation detection control system for a compressor.

FIG. 4 is an explanatory diagram of a conventional reverse rotation detection control system for a power supply circuit section and a compressor.

[Explanation of symbols]

1 ... Compressor, 2 ... Check valve, 3 ... Condenser, 4 ... Expansion valve, 5
... Evaporator, 6 ... Pressure detection port (discharge side), 7 ... Pressure detection port (suction side).

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Ken Kaneko, 390 Muramatsu, Shimizu City, Shizuoka Prefecture, Hitachi Air Conditioning Systems Division (72) Masayuki Aiyama 390, Muramatsu, Shimizu City, Shizuoka Hitachi Shimizu Engineering Co., Ltd. Within the corporation

Claims (1)

[Claims] 1. An air conditioner using a compressor whose rotational compression direction is fixed, wherein a pressure detection port is provided at a discharge portion of the compressor, and after the compressor is stopped, the compressor is started. Up to the specified time Δt until Δ using the pressure change rate ΔP of the discharge pressure detected from the pressure detection port of the discharge part
An air conditioner with a reverse rotation preventing function, which has a function of determining whether the compressor is stopped or continuously operating according to the condition determination of P / Δt 0.