JPS611954A - Capacity control type refrigeration cycle device - 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 [Technical Field of the Invention] The present invention relates to a capacity-controlled refrigeration cycle device, and particularly to a capacity-controlled refrigeration cycle device that can ensure stable operation during low-capacity operation.

[Prior art]

FIG. 1 is a system diagram showing a conventional refrigeration cycle device.
(1) is a compressor, (2) is an inverter that controls the rotation speed of compressor (1), (3) is a condenser, (4) is a fan, (
5) is a temperature-type expansion valve, (6) is an evaporator, (7) is a fan, and (8) is a temperature-sensitive cylinder of the temperature-type expansion valve (5) provided at the outlet of the evaporator (6).

The refrigerant gas compressed to high temperature and high pressure by the zero compressor (1), the operation of which will be explained next, is supplied to the condenser (3), where it is condensed and liquefied by dissipating heat through the action of the fan (4). This condensed liquid refrigerant is supplied to a thermostatic expansion valve (5), where it is depressurized and converted into a low-temperature, low-pressure liquid refrigerant. Next, the low-temperature, low-pressure liquid refrigerant is supplied to the evaporator (6), where it absorbs heat from the outside air by the action of the fan (7), evaporates, and returns to the compressor (1), forming a refrigeration cycle. The rotational speed of the compressor (1) is changed by the inverter (2) in accordance with changes in the load, thereby controlling the compression capacity.

In addition, the temperature-type expansion valve (5) has an opening degree equal to that of the temperature-sensitive tube (8).
The amount of refrigerant that passes through the refrigerant is controlled and the amount of superheat is kept constant.

Conventional capacity-controlled refrigeration systems are constructed as described above, however, the amount of superheat is kept constant by the temperature-sensitive cylinder (8) of the temperature-type expansion valve (5) as described above. Since the compressor (1) is controlled at low capacity, the oil return υ is poor when the compressor (1) is operated at low capacity, which causes the compressor (1) to seize and burn out the motor coil, making it inoperable. Ta.

[Summary of the invention]

This invention was made to improve such drawbacks,
The inlet temperature TI, intermediate temperature T1, and outlet temperature T of the evaporator are detected respectively, and during low capacity operation, the opening degree of the electric expansion valve is adjusted at fixed time intervals to maintain a heat amount of 8 hours for a predetermined period of time. This paper proposes a capacity-controlled refrigeration cycle device that can improve oil return in the compressor, prevent seizure of the compressor, and maintain stable operating conditions by controlling the amount of oil to zero.

[Embodiments of the invention]

FIG. 2 shows one embodiment of this invention, (1)
is a compressor, (2) is an inverter that can control the compression capacity by changing the rotation speed of the compressor (1), (3) u' is a condenser, (4) is a fan, and (6) is an evaporator. , (7) is a fan, (9) is an electric expansion valve whose opening degree can be adjusted by an electric signal, (4o) is an inlet temperature sensor installed at the inlet of the evaporator (6), (1i>Fii Intermediate temperature sensor installed in the middle of the container (6), (12)ii fumigator 6)
The outlet temperature sensor (13) provided at the outlet of the connected in a ring. In addition, the control device (13) receives detection signals from the inlet temperature sensor (10), intermediate temperature sensor (1)), and outlet temperature sensor (12), and based on these, the control device (13) Outputs a control signal to control the opening degree.

Next, the operation will be explained. The refrigerant gas compressed to high temperature and high pressure by the compressor (1) is supplied to the condenser (3), and is condensed and liquefied by dissipating heat by the action of the fan (4). This condensed liquid refrigerant is supplied to an electric expansion valve (9), which reduces the pressure and converts it into a low-temperature, low-pressure liquid refrigerant, and then supplies it to the evaporator (6) to operate its fan (7). This forms a refrigeration cycle that absorbs heat from the evening air, evaporates it, and returns to the compressor (1).

Now, assuming that the operating frequency of the compressor (1) is reduced to a low frequency by the inverter (2) and the compressor (1) is in low capacity operation, the control device (13)' is operated in this state, and the evaporator (1) is activated.
Based on the detection signals of the inlet temperature sensor (10), intermediate temperature sensor (1)) and outlet temperature sensor (12) provided in 6), the temperature T, %T, and T of each part are detected and Accordingly, at fixed time intervals, the electric expansion valve (9) is outputted with both signals, and the valve opening is forced for a predetermined period of time, and the amount of heat inr in the suit arm is reduced in this way.
By controlling the electric expansion valve (9) so that the current is zero, the lubricating oil accumulated in the piping of the compressor (1) can be returned to the compressor (1). Grilled'
It is possible to prevent sticking.

〔Effect of the invention〕

As explained above, in this invention, the inlet temperature T1 of the evaporator
By detecting the intermediate temperature T2 and the outlet temperature T3 and controlling the opening degree of the electric expansion valve during low capacity operation so that the amount of superheat is zero for a predetermined period of time, the lubricating oil in the compressor is This has the effect of improving the return of the compressor, preventing seizure of the compressor, and maintaining stable operating conditions.

[Brief explanation of the drawing]

FIG. 1 is a system diagram showing a conventional refrigeration cycle device, and FIG. 2 is a system diagram showing one embodiment of the present invention. In the figure, (1) is a compressor, (2) is an inverter, (
3) is a condenser, (6) is an evaporator, (9) is an electric expansion valve s (to)ti inlet temperature sensor% (1)) is an intermediate temperature sensor, (12) is an outlet temperature sensor, (13) ) is the control device. Note that the same reference numerals in each figure indicate the same or corresponding parts. Figure 1 Figure 2 Procedural amendment (voluntary) Showa 60 J] 6 Eyebrow 9 1. Indication of the case Japanese Patent Application No. 1987-122510 2. Name of the invention Capacity-controlled cryocycle device 3. Representative of the person making the amendment Part 4 to Hitoshi Katayama, attorney 5, column for the scope of claims and detailed description of the invention in the description of the subject matter of the amendment. -2. Claims (1) In a refrigerating recycling device in which a variable capacity compressor, a condenser, an electric expansion valve, and an evaporator are connected in a ring, 2. Detect the outlet temperature T3, and adjust the opening degree of the 1 distribution electric expansion valve at regular intervals during low capacity operation to maintain superheat 1- for a predetermined time.
Capacity control type refrigerating recycle device featuring Mi Sll.

Claims (1)

[Claims] (1) In a refrigeration cycle device in which a variable capacity compressor, a condenser, an electric expansion valve, and an evaporator are connected in a ring, the evaporator has an inlet temperature T_1, an intermediate temperature T_2, and an outlet temperature T_
3, and during low capacity operation, the opening degree of the electric expansion valve is adjusted at fixed time intervals to adjust the superheat amount SH for a predetermined time SH=T_3-{(T_1+T_2)/2}
1. A capacity control type refrigeration cycle device characterized in that the capacity control type refrigeration cycle device is controlled so that =0.