JPH0316586B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a control device for a refrigeration system in which a step type flow control valve is provided in a refrigerant circuit. A conventional refrigeration system, such as a refrigerator, is a system as shown in FIG. In Figure 1, A is a compressor, B is a condenser, and C is a compressor.
is a capillary reach tube, D is an evaporator, E is a thermostat installed on the suction side of the evaporator D, and F is a thermostat installed on the suction side of the evaporator D.
is the accumulator, and G is the thermostat E.
This is a controller that controls turning on and off of the compressor A by turning on and off the compressor A. Next, to explain the operation, the refrigerant is compressed by compressor A.
It is compressed into high-temperature, high-pressure gas, which is then transferred to condenser B.
It condenses into a high-temperature, high-pressure liquid. The refrigerant is depressurized in the capillary reach tube C to become a low-temperature, low-pressure liquid, absorbs heat in the evaporator D, and returns to the compressor A via the accumulator F, repeating the cycle. By the way, in the above-mentioned refrigeration system,
The thermostat E is turned on and off depending on the magnitude of the load, and the compressor A is repeatedly turned on and off via the controller G. Here, when the compressor A stops, refrigerant accumulates in the evaporator D, resulting in a large energy loss when the compressor A is restarted. Another drawback is that the temperature inside the refrigerator fluctuates considerably due to overshoot during restart. The above-mentioned drawbacks apply not only to refrigerators but also to room air conditioners. Therefore, in recent years, in addition to proportionally controlling the capacity of compressor A according to load fluctuations, a proportional control valve is connected to the refrigerant circuit, and this is also controlled according to load fluctuations to control the flow rate of refrigerant. something is being developed. According to this method, the drawbacks of the above-mentioned method in which the compressor A is turned on and off are improved by constantly driving the compressor A with a capacity according to the load, but the control system of the refrigeration system is delayed. However, even if proportional control is required to perform fairly complicated control, problems such as hunting occur and the cost of the control system increases. The present invention seeks to correct the above-mentioned drawbacks,
The purpose of this is to control the refrigerant using a step-type flow control valve, and to switch the capacity of the compressor in a step-type manner, allowing the compressor to continue operating without control under a certain load condition. It is an object of the present invention to provide a control device for a refrigeration system that can solve the above-mentioned conventional drawbacks. Next, an example of a step type flow control valve used in the present invention will be explained with reference to FIGS. 2 and 3. 1 is an excitation coil, 2 is a yoke into which the excitation coil 1 is fitted, and 3 is fixed to the yoke 2 with screws 4, and a plunger tube 5 inside the coil 1.
The suction element 6 inserted into the tube 5 is a plunger that is always biased in the valve opening direction by a spring 7, and the portion protruding from the tube 5 is a small diameter portion 6a. , and its tip is formed into a conical shape and serves as a valve portion 6b. Further, a pin 6c is fitted into the small diameter portion 6a. Reference numeral 8 denotes a valve body fitted to the outer periphery of the tube 5 protruding from the yoke 2, and includes an insertion hole 8a into which the small diameter portion 6a of the plunger 6 is inserted, and a fitting hole 8b into which the valve seat 9 is fitted. A horizontal hole 8c communicating with the insertion hole 8a is formed. A vertical hole 9a is formed in the valve seat 9, and the valve portion 6b of the plunger 6 faces one end of the vertical hole 9a. And this valve seat 9
The outflow pipe 10 is fitted into the horizontal hole 8c.
An inflow pipe 11 is fitted into the inflow pipe 11 . 12 is a stopper fixed in the valve body 8 in contact with the tube 5, and 13 is an annular guide fitted in the insertion hole 8a of the valve body 8 between the stopper 12 and the step 8d. The fixture has an annular recess 13a formed in the center of its inner peripheral surface. Reference numerals 14 and 15 designate annular first and second guides having sawtooth step portions 14a and 15a, which are fixed to the inner periphery of the guide fixture 13 at a predetermined interval. Note that the second guide 15 has sawtooth-shaped step portions 15a whose heights change sequentially, and step portions 15a of the same height.
are formed facing each other. In addition, the first and second guides 14 and 15 have one mountain part 14b (15b) and the other valley part 15c (14
It is arranged so as to correspond to the center of c) and is shifted by a half pitch. The pin 6c of the plunger 6 is located between the stepped portions 14a and 15a of the first guide 14 and the second guide 15. Therefore,
Since the plunger 6 is pressed by the spring 7, the pin 6c is in contact with one of the step portions 15a of the second guide 15. Next, the operation will be explained based on the above structure. When current to the coil 1 is cut off, the valve portion 6b of the plunger 6 is pressed toward the valve seat 9 by the spring force of the spring 7. At this time, the pin 6c fixed to the plunger 6
contact with any of the troughs 15c of the stepped portions 15a of No. 5,
The position of the plunger 6 is determined by the depth of the valley portion 15c, and therefore the gap between the valve portion 6b and the valve seat 9 is determined by this discharge amount. Next, to explain the operation, when current flows through the coil 1, the plunger 6 is attracted against the spring force of the spring 7. When the plunger 6 is sucked, the pin 6c is attached to the stepped portion 1 of the first guide 14.
4a, the plunger 6 rotates as it rises (in FIG. 2), the pin 6c is located in the valley 14c, and the plunger 6 contacts the suction element 3. stop at the time.
Then, when the current to the coil 1 is cut off, the plunger 6 is pushed down by the spring force of the spring 7. When the plunger 6 descends, the pin 6c comes into contact with the slope of the peak 15b of the step 15a of the second guide 15, and therefore the plunger 6
rotates as the pin 6c descends, and the pin 6c reaches the trough 15.
It stops when it reaches position c. Here, since the trough 15c where the pin 6c is located is formed in five stages, if the trough 15c where it was located last time is the lowest, it moves to the next second lowest trough 15c, Thereafter, the robot moves to the higher valleys 15c in the same way, and if it is located at the highest valley 15c, it moves to the lowest valley 15c. Then, this step type flow control valve H is inserted into the refrigerant circuit of the refrigerator shown in FIG. 4, or into the refrigerant circuit of the room air conditioner shown in FIG. The operation of this refrigerant circuit will be explained below. In addition, in the figure, the same reference numerals as in FIG. 1 indicate the same members, and explanations thereof will be omitted. In Figures 4 and 5, I ₁ and I ₂ are internal temperature sensors or indoor temperature sensors, A is a variable capacity compressor whose capacity decreases as the input frequency decreases,
J is a four-way switching valve for switching the room air conditioner between cooling and heating. Further, in the above-mentioned step type flow rate control valve H, the valve opening degree is switched to five stages: fully closed, 40%, 60%, 80%, and fully open, each time the coil 1 is energized. Furthermore, the controller G varies the capacity of the compressor A according to the temperature signal from the internal temperature sensor _I1 or the indoor temperature sensor _I2 , and controls the flow rate control valve H to the opening degree according to the capacity. Moreover, the valve position of the flow control valve H is also detected. Next, to explain the operation shown in FIG. 4, the system is operated as described in the conventional method, and when the temperature sensor I ₁ detects a temperature of -16°C or higher, the controller G controls the voltage supplied to the compressor A. The frequency of is controlled to 90Hz, its capacity is controlled to 100%, and the opening degree of flow control valve H is controlled to be fully open. As a result, when the temperature inside the refrigerator reaches -18 to -16℃, controller G changes the frequency of the voltage supplied to compressor A to 70℃.
Hz, and control the flow rate control valve H to 80% opening. Similarly, as shown in the table below, the controller G controls the compressor A and the flow rate control valve H in stages according to the internal temperature.

[Table] In addition, for both cooling and heating in a room air conditioner, the controller G varies the frequency of the voltage supplied to the compressor A and controls the flow rate according to the temperature detected by the room temperature sensor _I2 as shown in the table below. Valve H
The opening degree is controlled in stages.

[Table] The above tables show one example, and the capacity of the compressor A and the opening degree of the flow control valve H against temperature changes can be freely set according to the system used. As described above, the present invention sets the control range of the refrigeration system in several stages, and when the load condition is within one range, the compressor and flow control valve are kept in the previous control condition, and When the load condition goes out of one range, the capacity of the compressor and the opening degree of the flow control valve are changed in stages, so that the compressor can be turned on or off depending on small fluctuations in the load. This eliminates the energy loss that occurs when controlling the compressor on and off, and also reduces temperature changes due to overshoot, etc.
Compared to the proportional control method, the control system is simpler and costs can be reduced accordingly.

[Brief explanation of the drawing]

Figure 1 shows the refrigeration system in a conventional refrigerator.
2 and 3 are a sectional view and a partial perspective view showing an example of a step type flow control valve used in the control device of the present invention, and FIGS. 4 and 5 are refrigeration systems for explaining the control device of the present invention. It is. A...Compressor, B...Controller, H...Flow control valve.

Claims (1)

[Claims] 1. In a refrigeration system equipped with a refrigeration cycle that sequentially passes through a compressor, a condenser, a flow control valve, an evaporator, etc., a compressor whose capacity changes depending on the frequency of the applied power supply; When the plunger is energized, the valve part moves away from the valve seat and is rotated by a predetermined angle by the first guide, and when the plunger is de-energized and the valve part approaches the valve seat, it is moved by the second guide. a step type flow control valve that is rotated by a predetermined angle and the return amount changes to change the distance between the valve portion and the valve seat; a temperature sensor that detects a temperature on the outlet side of the evaporator; When the output falls within a preset temperature range, a voltage with a preset power frequency corresponding to the temperature range is applied to the compressor to vary the capacity in stages, and the plunger of the flow control valve is applied to the compressor. A controller for controlling a refrigeration system, comprising: a controller that gradually changes the opening of a valve to a preset value by applying electricity;