JPS6240637B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a refrigerant amount adjusting device that can change the amount of refrigerant circulating in a refrigerant circuit in response to a change in load, and can exhibit the maximum refrigerating capacity according to the load. It is something.

Conventionally, a refrigeration system equipped with a refrigerant amount adjustment device connects a compressor a, a condenser b, a throttle device c, and an evaporator d in a ring, and throttles a refrigerant amount adjustment container e, as shown in Fig. 1. At connection position g in the middle of device c,
Alternatively, a configuration is known in which a suction pipe f is connected between the throttle device c and the evaporator d, and further connects the compressor a and the evaporator d, through the refrigerant amount adjustment container e.

In such a configuration, the refrigerant at the connection position g between the expansion device c and the refrigerant amount adjustment container e is in a gas-liquid two-phase saturated state. Therefore, if the suction pipe f does not penetrate the refrigerant amount adjustment container e, the state of the refrigerant inside the refrigerant amount adjustment container e is the same as that of the refrigerant at the connection position g between the expansion device c and the refrigerant amount adjustment container e. Become saturated. However, the suction pipe f is
If the suction pipe f passes through the
Since the temperature is lower than that of , a part of the refrigerant inside the refrigerant amount adjustment container e condenses. Therefore, the wetness of the refrigerant inside the refrigerant amount adjusting container e is greater than the wetness of the refrigerant at the connection position g between the expansion device c and the refrigerant amount adjusting container e. In other words, when the temperature of the suction pipe f is lower than the temperature of the connection position g,
The refrigerant is simply accumulated in the refrigerant amount adjustment container e.

The change in the state of the refrigerant inside the refrigerant amount adjusting container e described above with respect to the load will be explained using FIG. 2.
When considering the heat balance of the refrigerant amount adjustment container e, the main amount of heat is the amount of heat that enters the refrigerant amount adjustment container e due to heat transfer from the air around the refrigerant amount adjustment container e, and the amount of heat that enters the refrigerant amount adjustment container e. There is an amount of heat taken away from the refrigerant amount adjustment container e by the suction pipe f passing through the refrigerant amount adjusting container e. Figure 2 shows the heat balance of the refrigerant amount adjustment container e with respect to load fluctuations of the refrigeration device, with the horizontal axis representing the load on the refrigeration system and the vertical axis representing the amount of heat entering the refrigerant amount adjustment container e. This is what I did. However, the fact that the amount of heat entering is negative means that the amount of heat is taken away from the refrigerant amount adjustment container e. In FIG. 2, the curve q ₁ represents the change in the amount of heat entering from the surrounding air with respect to the load, and the curve q ₂ represents the change in the amount of heat entering from the suction pipe f with respect to the load. The total amount of heat that enters the refrigerant amount adjustment container e is the sum of q ₁ and q ₂ , and this total amount of heat that enters is represented by the curve q ₃ . Here, the point x on the curve _q3 means that there is no amount of heat entering the refrigerant amount adjustment container e.

By the way, the case where the refrigerant amount adjustment container e performs the refrigerant amount adjustment function is only when the load changes within a certain range around the load represented by the point x. This is because when the load becomes much larger than the load at point x, the refrigerant amount adjustment container e
The refrigerant inside is always in a superheated vapor state, and even if there is a load change, only the degree of superheating of the refrigerant inside the refrigerant amount adjustment container e changes, and the refrigerant accumulated inside the refrigerant amount adjustment container e There is almost no change in the mass of On the other hand, when the load becomes much smaller than the load at point Only the degree of cooling changes, and there is almost no change in the mass of the refrigerant accumulated inside the refrigerant amount adjustment container e. However, the typical load range in which the refrigeration system is used is the range shown by points m and n in FIG. In other words, the normal load range in which the refrigeration system is used is considerably lower than the load represented by point x.

As is clear from the above explanation, in the normal load range in which the refrigeration system is used, the interior of the conventional refrigerant amount adjustment container e is occupied by supercooled liquid, and the refrigerant amount is adjusted only in an extremely large load range. It has the disadvantage that it does not perform the function of regulating the amount of refrigerant within the normal load range in which the refrigeration system is used. Particularly at low loads, the disadvantage was that liquid returned to the compressor.

Therefore, the present invention provides a discharge pipe connecting the compressor and the condenser, or a branch pipe branched from the discharge pipe, to the refrigerant amount adjustment container for heat exchange to increase the amount of heat that enters the refrigerant amount adjustment container. This system changes the amount of refrigerant flowing through the refrigerant circuit even when the load fluctuates, allowing the refrigeration system to always perform at its maximum capacity in accordance with the load.

An embodiment of the present invention will be explained with reference to FIGS. 3 and 4. FIG. As shown in FIG. 3, a compressor 1, a condenser 2, a throttle device 3, and an evaporator 4 are each connected in a ring. The refrigerant amount adjustment container 5 is connected to a connection position 3a in the middle of the expansion device 3. Further, the suction pipe 6 connects the compressor 1 and the evaporator 4. Further, a branch pipe 7a is provided in the discharge pipe 7 that connects the compressor 1 and the condenser 2, and one end of this branch pipe 7a is connected to a branch point 7b in the middle of the discharge pipe 7. The end is connected to a confluence point 7c located in the middle of the discharge pipe 7 closer to the condenser 2 than the branch pipe 7b. Further, as shown in FIG. 4, the suction pipe 6 and the branch pipe 7a are respectively disposed through the refrigerant amount regulating container 5 for heat exchange.

The operation of the refrigerant amount adjusting device described above will be explained below.

Generally, the temperature of the suction pipe 6 changes sensitively and greatly with respect to load fluctuations, but the temperature of the connection position 3a between the refrigerant amount adjustment container 5 and the expansion device 3 does not change much.

Now, assume that the refrigerant is filled with the necessary refrigerant so that the refrigeration system exhibits its maximum capacity under certain design heat load conditions. When the refrigeration system is operated under a certain load condition, the temperature of the suction pipe 6 is also maintained at a certain temperature. At this time,
The temperature of the suction pipe 6 penetrating the refrigerant amount adjustment container 5 is lower than the temperature of the connection position 3a between the refrigerant amount adjustment container 5 and the expansion device 3, and the temperature of the branch pipe 7a is lower than the temperature of the connection position 3a between the refrigerant amount adjustment container 5 and the expansion device 3. higher than the temperature. Therefore, the temperature of the refrigerant inside the refrigerant amount adjustment container 5 shows a saturation temperature equal to the temperature of the refrigerant at the connection position 3a between the refrigerant amount adjustment container 5 and the expansion device 3; Wetness of refrigerant and connection position 3
The wetness of the refrigerant in a will be different. When adjusting the amount of refrigerant, it is important to adjust the wetness of the refrigerant inside the refrigerant amount adjustment container 5. In other words, since there is a large difference in specific weight between the gas state and the liquid state of the refrigerant, it is important to adjust the amount of refrigerant. Controlling the proportion of the liquid phase of the refrigerant inside the container 5 is important. Figure 5 shows branch pipe 7 on the horizontal axis.
The liquid phase ratio of the refrigerant inside the refrigerant amount adjustment container 5 under a certain design heat load condition is calculated by taking the pipe diameter of a and taking the wetness of the refrigerant inside the refrigerant amount adjustment container 5 on the vertical axis. This is what is shown. For example, in FIG. 5, if a branch pipe 7a with a diameter indicated by point h is used, the wetness of the refrigerant inside the refrigerant amount adjustment container 5 will be i under the design load conditions. As explained above, the wetness of the refrigerant inside the refrigerant amount adjusting container 5 can be set to any desired wetness by appropriately selecting the pipe diameter of the branch pipe 7a. As shown in Fig. 6, by providing fins 8 on the suction pipe 6 and the branch pipe 7a and changing the heat transfer area thereof, the wetness of the refrigerant inside the refrigerant amount adjustment container 5 can be appropriately selected. .

Next, the operation of the refrigerant amount adjusting device when the load fluctuates will be explained. First, considering the case where the load decreases, an excess amount of refrigerant will be circulating in the refrigerant circuit than the amount of refrigerant that allows the refrigeration system to exhibit its maximum capacity under this load condition, so the refrigerant with almost no superheat will be It is sucked into the compressor 1 through the suction pipe 6. Alternatively, part of the refrigerant will be sucked into the compressor 1 through the suction pipe 6 while remaining in a liquid state,
The temperature of the suction pipe 6 becomes lower than before the load is reduced. Furthermore, if the load decreases, the temperature of the refrigerant discharged from the compressor 1 generally decreases, so the temperature of the branch pipe 7a also decreases. In this way, when the load decreases, the temperatures of both the suction pipe 6 and the branch pipe 7a passing through the refrigerant amount adjustment container 5 decrease. Therefore, the refrigerant in the saturated vapor state inside the refrigerant amount adjustment container 5 condenses, so the refrigerant amount adjustment container 5
The wetness of the refrigerant inside increases, and the proportion of the liquid phase of the refrigerant increases. As a result, the mass of the refrigerant contained inside the refrigerant amount adjustment container 5 increases compared to before the load change. This increased refrigerant is the refrigerant that has flowed into the refrigerant amount adjustment container 5 from the connection position 3a in the middle of the expansion device 3, so that the excess refrigerant in the refrigerant circuit has been removed. As a result, the temperature of the suction pipe 6 rises to balance the temperature of the connection position 3a.

Next, the operation of the refrigerant amount adjusting device when the load increases will be explained. When the load increases, the amount of refrigerant circulating in the refrigerant circuit becomes insufficient than the amount of refrigerant that allows the refrigeration system to exhibit its maximum capacity under this load condition.
It will be sucked into the compressor 1 through.
In other words, the temperature of the suction pipe 6 becomes higher than before the load change. Additionally, as the load increases, the temperature of the refrigerant discharged from the compressor 1 generally increases;
The temperature of the branch pipe 7a also increases. In this way, if the load increases, the temperatures of both the suction pipe 6 and the branch pipe 7a that pass through the refrigerant amount adjustment container 5 will increase. Therefore, the refrigerant in the saturated liquid state inside the refrigerant amount adjustment container 5 evaporates, so the refrigerant amount adjustment container 5
The wetness of the refrigerant inside becomes smaller, and the proportion of the liquid phase of the refrigerant becomes smaller. As a result, the mass of the refrigerant contained inside the refrigerant amount adjustment container 5 decreases compared to before the load change. This decreased refrigerant is the refrigerant that has flowed into the refrigerant circuit from the connection position 3a in the middle of the expansion device 3, and the refrigerant inside the refrigerant amount adjustment container 5 has flowed into the refrigerant circuit, which was in short supply. As the refrigerant is replenished, the temperature of the suction pipe 6 decreases and becomes balanced with the temperature of the connecting position 3a in the middle of the expansion device 3.

The change in the state of the refrigerant inside the refrigerant amount adjusting container 5 described above with respect to the load will be explained using FIG. 7.
When considering the heat balance of the refrigerant amount adjustment container 5, as explained in the conventional example, the main amount of heat enters the refrigerant amount adjustment container 5 by heat transfer from the air around the refrigerant amount adjustment container 5. Heat amount and refrigerant amount adjustment container 5
There is an amount of heat taken away from the refrigerant amount adjusting container 5 by the suction pipe 6 passing through the refrigerant amount adjusting container 5. Furthermore, in the present invention, the branch pipe 7a penetrating the refrigerant amount adjustment container 5
There is an amount of heat that enters the refrigerant amount adjustment container 5 from the inside.

FIG. 7 illustrates the heat balance of the refrigerant amount adjustment container 5 with respect to load fluctuations of the refrigeration device, with the horizontal axis representing the magnitude of the load on the refrigeration system and the vertical axis representing the amount of heat entering the refrigerant amount adjustment container 5. This is what I did. However, the fact that the amount of heat entering is negative means that the amount of heat is taken away from the refrigerant amount adjustment container 5. In Figure 7, song q ₄
represents the change in the amount of heat entering from the ambient air with respect to the load, and the curve q ₅ represents the change in the amount of heat entering from the suction pipe 6 with respect to the load. moreover,
The curve q ₆ represents the change in the amount of heat entering from the branch pipe 7a with respect to the load. Further, the total amount of heat that enters the refrigerant amount adjustment container 5 is the sum of q ₄ , q ₅ , and q ₆ , and this total amount of heat that enters is represented by the curve q ₇ . Point y on the curve q ₇ is the refrigerant amount adjustment container 5
This indicates that there is no amount of heat penetrating.

Now, in FIG. 7, if the normal load under which the refrigeration system is used is represented by the range between points m and n, then as explained in FIG. 5, the branch pipe 7a
By appropriately selecting the pipe diameter of , it is possible to position point y on curve q ₇ between points m and n, which are the normal load range.

Next, FIG. 8 shows another embodiment of the refrigerant amount adjusting device according to the present invention. The difference between FIG. 3 and FIG. 8 explained earlier is that in FIG.
A branch pipe 7a branched from the discharge pipe 7 connecting the
It is characterized by passing through the refrigerant amount adjusting container 5, and in FIG. This is a distinctive feature.

The refrigerant amount adjusting device shown in FIG. 8 also provides the same effects as the previous embodiment. Here, the same parts as in FIG. 3 are given the same numbers and their explanation will be omitted.

In the examples shown in FIGS. 3, 4, 6, and 8, a discharge pipe 7 connecting the compressor 1 and the condenser 2, or a branch pipe branched from the discharge pipe 7 7a and the suction pipe 6 are passed through the refrigerant amount adjustment container 5, but the meaning of this penetration is that the discharge pipe 7 or the branch pipe 7a and the suction pipe 6 are inserted into the refrigerant amount adjustment container 5. It is to exchange heat with 5. Therefore, the discharge pipe 7 or the branch pipe 7a and the suction pipe 6 may be placed in contact with the refrigerant amount adjustment container 5 to exchange heat.

As described above, the refrigerant amount adjusting device of the present invention has a compressor, a condenser, a throttling device, and an evaporator connected together in a ring, and the refrigerant amount adjusting container is placed in a connecting position in the middle of the throttling device or with the throttling device. A discharge pipe connected between the evaporator and the compressor and the condenser, or a branch pipe and a suction pipe branched from the discharge pipe are disposed in the refrigerant amount adjusting container for heat exchange. It is something that Therefore, the refrigerant amount can be adjusted over a wider range of load fluctuations than conventional refrigerant amount adjustment devices.

Furthermore, unlike conventional refrigerant amount adjustment devices, a discharge pipe that connects the compressor and the condenser, or a branch pipe that is a branched part of the discharge pipe, is arranged in the refrigerant amount adjustment container for heat exchange. Therefore, by appropriately selecting the diameter of the discharge pipe or the diameter of the branch pipe, it is possible to arbitrarily select the amount of refrigerant that can be stored in the refrigerant amount adjustment container under the design load condition. Therefore, there is an advantage that the size of the refrigerant amount adjustment container can be easily determined so that the refrigerant amount adjustment function can be sufficiently performed for the maximum load condition and the minimum load condition considered at the time of design.

Furthermore, the refrigerant amount adjusting device according to the present invention has the advantage that it can completely prevent liquid from returning to the compressor, since it can sufficiently adjust the amount of refrigerant especially during low loads.

[Brief explanation of the drawing]

FIG. 1 is a diagram of a refrigeration cycle equipped with a conventional refrigerant amount adjustment device, FIG. 2 is an explanatory diagram showing the heat balance of the refrigerant amount adjustment container, and FIG. 3 is a diagram of a refrigerant amount adjustment device according to an embodiment of the present invention. 4 is an enlarged partial cross-sectional view showing the refrigerant amount adjustment container used in the present invention, FIG. 5 is an explanatory diagram showing the wetness of the refrigerant in the refrigerant amount adjustment container, and FIG. 6 is a sectional view showing another example of the refrigerant amount adjustment container, FIG. 7 is an explanatory diagram showing the heat balance of the refrigerant amount adjustment container in one embodiment of the present invention, and FIG. 8 is a refrigeration diagram in another embodiment of the invention. It is a cycle diagram. 1... Compressor, 2... Condenser, 3... Throttle device, 4... Evaporator, 5... Refrigerant amount adjustment container, 6...
... Suction pipe, 7... Discharge pipe, 7a... Branch pipe.

Claims (1)

[Claims] 1 A compressor, a condenser, a throttling device, and an evaporator are each connected in a ring, and a refrigerant amount adjustment container is connected to a position between the throttling device and the evaporator where the pressure is lower than the pressure on the inlet side of the throttling device. and a refrigerant in a refrigeration system in which a discharge pipe connecting the compressor and the condenser and a suction pipe connecting the evaporator and the compressor are disposed in the refrigerant amount adjusting container in a heat exchange manner. Amount control device.