JPS6127464A - Refrigerator - 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 Field of Industrial Application The present invention provides a two-way valve using a valve drive element made of a shape memory alloy in a refrigeration cycle, and automatically opens and closes a pipe line depending on the refrigerant temperature. This relates to a refrigeration system that performs

Conventional configuration and its problems When the compressor that makes up the refrigeration cycle is stopped for a long time, a so-called stagnation phenomenon occurs in which the refrigerant dissolves into the lubricating oil inside the compressor. If the compressor is started in this state, the refrigerant dissolved in the lubricating oil will rapidly evaporate, a foaming phenomenon will occur, and the lubricating oil will protrude outside the compressor, resulting in poor lubrication and damage to bearings and other moving parts. It may cause damage to the parts.

Therefore, conventionally, in order to prevent stagnation, a crankcase heater 8 was placed at the bottom of the compressor 1 as shown in Fig. 1, and the power was turned on all the time when the compressor 1 was stopped, or it was turned on several hours before the compressor was started. Therefore, a method has generally been adopted in which the forming phenomenon is alleviated by diluting the concentration of refrigerant dissolved in the lubricating oil by increasing the temperature of the compressor 1.

However, in this method, the crankcase heater 8 is energized for a long time when the compressor 1 is stopped, which lowers the energy efficiency during the period, and also requires parts to control the energization of the crankcase heater 8, resulting in high costs. Become. moreover,
It had a number of drawbacks, including safety issues due to long-term energization.

Purpose of the Invention The present invention has been made in view of the drawbacks of the above-mentioned conventional examples.
A three-way valve made of shape memory alloy and using a valve drive element is installed in the middle of the refrigerant pipe connected to the compressor, and after the compressor is stopped, the refrigerant temperature in the pipe decreases or rises to below or above the set temperature. The purpose of this is to reduce the amount of refrigerant that moves to the compressor and stays in the lubricating oil by automatically closing the pipe line when

Structure of the Invention In order to achieve the above object, the refrigeration system of the present invention comprises a refrigeration cycle in which a compressor, a condenser, a pressure reducer, and an evaporator are sequentially connected by refrigerant piping, and A two-way valve is provided in the middle of the refrigerant pipe, and the two-way valve is composed of an inlet port, an outlet port, a valve body, and a valve driving element made of a shape memory alloy.

Description of examples Embodiments of the present invention will be described in detail below with reference to the drawings.

Fig. 2 is a refrigeration cycle diagram in which a two-way valve is provided in each refrigerant pipe connected to a high-pressure housing type compressor, according to an embodiment of the present invention. FIG. 4 is a diagram showing the characteristics of a coil spring-shaped valve drive element made of a shape memory alloy. 5 is a diagram showing temporal changes in refrigerant temperature within the two-way valve.

In FIG. 2, a high-pressure housing type compressor 1, a first three-way valve 9, a condenser 2, a pressure reducer 4, an evaporator 5, a second three-way valve 10. and the accumulator 7 are sequentially connected by a refrigerant pipe 16 to form a refrigeration cycle. 3 is a condenser fan, and 6 is an evaporator fan.

In FIG. 3, 11 is a three-way valve body having an inlet port 12 and an outlet port 13 at both ends. Inside the two-way valve body 11, there is a valve driving element 14 in the form of a coil spring made of a shape memory alloy, and one end is connected to the outlet port 13 and the other end is connected to the valve body 15 by an appropriate means such as welding or gluing. are joined together.

Here, the coil spring-shaped valve drive element 14 is made of a shape memory alloy that exhibits so-called two-way operation, and the first
In the two-way valve 9, as shown in Fig. 4 ta+, at high temperature (
The length of the coil spring is stored in advance so that it becomes 42 when T>T2) and 11 when the temperature is low (T>T1). This shape change occurs rapidly in a certain temperature range of the pot, and the shape change temperature range can be adjusted by the composition of the shape memory alloy or heat treatment. The characteristics of the second two-way valve 10 are opposite to those of the first two-way valve 9, as shown in FIG. 4 [al].

Next, the operation of the above configuration will be explained with reference to FIG.

During cooling operation, the gas refrigerant compressed to high temperature and high pressure by the compressor 1 passes through the first two-way valve 9 and becomes high temperature and high pressure liquid refrigerant in the condenser 2, and then is depressurized by the pressure reducer 4 to become a low temperature and low pressure liquid refrigerant. The refrigerant becomes a gas-liquid two-phase refrigerant, evaporates in the evaporator 5, and passes through the second two-way valve 10. It passes through the accumulator 7 and returns to the compressor 1. At this time, the evaporator 5 exchanges heat with the surrounding air, and the evaporator fan 6 blows out the cold air toward the air-conditioned room. Thereafter, when the operation switch of the air conditioner is turned off, the compressor 1, condenser fan 3, and evaporator fan 6 are stopped, and the circulation of refrigerant and air is stopped.

For this reason, in the first two-way valve 9, while the compressor 1 was in operation, high-temperature gas refrigerant was passing through it, and the compressor 1 stopped, although it was in the state shown in Figure 3 (bl). When the refrigerant temperature decreases and becomes below the set temperature (T<T1),
As shown in FIG. 3(a), due to the characteristics of the shape memory alloy, the coil spring-shaped valve drive element 14 expands, and the valve body 15 comes into contact with the inlet port 12, closing the pipe line.

On the other hand, in the second two-way valve 10, when the compressor 1 is stopped and the refrigerant temperature rises and becomes equal to or higher than the set temperature (T>T4), the coil spring-shaped valve drive element 14 expands and the valve body 15
comes into contact with the inlet port 12, closing the conduit. Thereafter, when the operation switch of the air conditioner is turned on, the compressor 1 etc. are started, and when the refrigerant temperature in the first two-way valve 9 reaches or exceeds the set temperature (T>T2), the valve drive element 14 starts. Upon contraction, the valve body 15 leaves the inlet port 12 and opens the pipeline. On the other hand, when the refrigerant temperature in the second two-way valve 10 becomes equal to or lower than the set temperature (T<T3), the conduit becomes open due to the same action as described above.

As described above, in this embodiment, the first two-way valve 9 uses a coil spring-shaped valve drive element 14 made of a shape memory alloy in the middle of the refrigerant pipe 16 connected to the compressor 1;
A second two-way valve 10 is provided to automatically open and close the pipeline by sensing the refrigerant temperature and utilizing the expansion and contraction of the valve drive element 14. That is, after the compressor 1 is stopped, the refrigerant temperature decreases in the first two-way valve 9 and becomes lower than the set temperature (T<TI), and the pipe becomes closed, and the second two-way valve 10 When the refrigerant temperature rises and exceeds the set temperature (T>T4), the pipe becomes closed,
It is possible to prevent the refrigerant from moving from the condenser 2 side and the evaporator 5 side to the compressor 1 and being dissolved in the lubricating oil in the compressor 1. In this way, the stagnation phenomenon that occurs when the compressor 1 is stopped for a long time can be suppressed compared to the conventional case, and the forming phenomenon at the time of startup can be alleviated.

Also, when the compressor 1 is in operation, the first three-way valve 9 and the second
In the two-way valve 10, as shown in FIG. Unlike the case where the pipeline is opened by dynamic pressure, the flow resistance is extremely small.

In this example, a three-way valve was provided for each refrigerant pipe connected to the high-pressure housing type compressor, but according to the present invention, the refrigerant pipe is connected to the space in the compressor where lubricating oil exists with extremely low flow resistance. In this example, even if a three-way valve is provided only in the pipe between the compressor and the condenser, the refrigerant pipe that is almost in communication with the lubricating oil can be closed when the compressor is stopped. By doing so, it is possible to considerably suppress the refrigerant from penetrating into the lubricating oil, so that the same effect as that of the present embodiment can be obtained.

Furthermore, the present invention is applicable not only to high-pressure housing type compressors but also to low-pressure housing type compressors.

Effects of the Invention As is clear from the above embodiments, the refrigeration system of the present invention has the following features:
A compressor, a condenser, a pressure reducer, and an evaporator are sequentially connected through refrigerant piping to constitute a refrigeration cycle, and a two-way valve is provided in the middle of the refrigerant piping connected to the compressor, and the two-way valve is It is composed of an inlet port, an outlet port, a valve body, and a valve drive element made of shape memory alloy.If the refrigerant temperature in the one-way valve decreases or increases to below or above the set temperature after the compressor has stopped, The valve drive element senses the temperature and automatically closes the pipe line, which prevents the refrigerant from dissolving in the lubricating oil inside the compressor and alleviates the forming phenomenon during startup. In addition, since a valve driving element made of a shape memory alloy is used, there is no need for electrical signals or an electrical drive source, and there is no need for electrical input such as a crankcase heater. It is effective.

[Brief explanation of the drawing]

FIG. 1 is a refrigeration cycle diagram showing a conventional example, FIG. 2 is a refrigeration cycle diagram showing an embodiment of the present invention, and FIG.
1 is a cross-sectional view of a two-way valve constructed of a valve driving element made of a shape memory alloy during a closing operation and an opening operation, respectively;
FIG. 4 (al and bl are diagrams showing different characteristics of valve drive elements made of the same shape memory alloy as material, and FIG. 5 is a diagram showing temporal changes in refrigerant temperature in the same two-way valve. 1... Compressor, 2... Condenser, 4...
... pressure reducer, 5 ... evaporator, 16 ...
... Refrigerant piping, 9, 10... Two-way valve, 12...
...Inlet port, 13 ...Outlet port, 1
5... Valve body, 14... Valve drive element. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 3 Figure 4 Figure 2

Claims (1)

[Claims] A refrigeration cycle is constructed by sequentially connecting a compressor, a condenser, a pressure reducer, and an evaporator with refrigerant piping, and a two-way valve is provided in the middle of the refrigerant piping connected to the compressor, and the two-way valve is A refrigeration system consisting of an inlet port, an outlet port, a valve body, and a valve drive element made of shape memory alloy.