JPS6240633B2 - - 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
, the temperature of the suction pipe f is usually lower than the temperature of the connection position g between the throttle device c and the refrigerant amount adjustment container e, so that some of the refrigerant inside the refrigerant amount adjustment container e Condense. 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, a curve q1 represents a change in the amount of heat entering from the surrounding air with respect to the load, and a curve q2 represents a 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 q1 and q2, and this total amount of heat that enters is represented by a curve q3. 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 adjusting container e performs the function of adjusting the refrigerant amount is only when the load changes within a certain range around the load represented by the point x. This is because when the load is much larger than the load at point x, the refrigerant amount adjustment container e
The refrigerant inside the refrigerant 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, in the normal load range in which the refrigeration system is used, the amount of heat that the suction pipe f takes away from the refrigerant amount adjustment container e (the amount of heat for which the amount of heat entering is negative) is too large, so the load indicated by point x is is considerably higher than the normal load range in which it is used.

As is clear from the above explanation, in the normal load range in which the refrigeration system is used, the inside of the conventional refrigerant amount adjustment container e is occupied by supercooled liquid, and the refrigerant amount adjustment function is only available in extremely large load ranges. However, it has the disadvantage that it hardly functions to adjust 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 branch pipe in the suction pipe to suppress the amount of heat taken from the refrigerant regulating container, and changes the amount of refrigerant flowing in the refrigerant circuit even in response to normal load fluctuations, so that the amount of refrigerant flowing through the refrigerant circuit is always adjusted according to the load. This enables the refrigeration equipment to demonstrate its maximum capacity.

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, and one end of a branch pipe 6a provided in the suction pipe 6 is connected to the suction pipe 6.
The other end of the branch pipe 6a is connected to the branch point 6b in the middle of the suction pipe 6.
The confluence point 6c is located closer to the compressor 1 than the compressor 1 side. Further, as shown in FIG. 4, the branch pipe 6a is disposed in 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 and the branch pipe 6a changes sensitively and greatly with respect to load fluctuations.
Connection position 3a between refrigerant amount adjustment container 5 and expansion device 3
temperature does not change much.

Now, it is assumed that the refrigerating system is filled with the necessary refrigerant so that it can exhibit 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 and the temperature of the branch pipe 6a are both maintained at a certain temperature. At this time, the temperature of the branch pipe 6a penetrating the refrigerant amount adjustment container 5 becomes lower than the temperature at the connection position 3a between the refrigerant amount adjustment container 5 and the expansion device 3. 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; The humidity of the refrigerant and the humidity of the refrigerant at the connection position 3a are different. When adjusting the amount of refrigerant, use the refrigerant amount adjustment container 5.
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 the specific weight of the refrigerant between the gaseous state and the liquid state, it is important to control the proportion of the liquid phase of the refrigerant inside the refrigerant amount adjustment container 5. is important. In FIG. 5, the diameter of the branch pipe 6a is plotted on the horizontal axis, and the humidity of the refrigerant inside the refrigerant amount regulating container 5 is plotted on the vertical axis. 5 shows the ratio of the liquid phase of the refrigerant inside No. 5. For example, in FIG. 5, a branch pipe 6a with a pipe diameter indicated by point h
Assuming that, under the design load conditions, the humidity of the refrigerant inside the refrigerant amount adjustment container 5 is i. As explained above, the humidity of the refrigerant inside the refrigerant amount adjusting container 5 can be set to any desired humidity by appropriately selecting the pipe diameter of the branch pipe 6a. As shown in FIG. 6, by providing fins 8 on the branch pipe 6a 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 and the branch pipe 6a. Alternatively, part of the refrigerant will be sucked into the compressor 1 through the suction pipe 6 and the branch pipe 6a while remaining in a liquid state, and the refrigerant will be sucked into the compressor 1 through the suction pipe 6 and the branch pipe 6a.
temperature will be lower than the load decreases. Therefore, the refrigerant in a saturated vapor state inside the refrigerant amount adjustment container 5 condenses, so that the wetness of the refrigerant inside the refrigerant amount adjustment container 5 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 temperatures of the suction pipe 6 and the branch pipe 6a rise 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 temperatures of the suction pipe 6 and the branch pipe 6a become higher than before the load change. For this reason, the refrigerant in a saturated liquid state inside the refrigerant amount adjustment container 5 evaporates, so the wetness of the refrigerant inside the refrigerant amount adjustment container 5 decreases, and the proportion of the liquid phase of the refrigerant decreases.
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.
The refrigerant is replenished into the refrigerant circuit that was lacking, and the temperature of the suction pipe 6 and branch pipe 6a decreases.
This balances 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. The refrigerant amount adjustment container 5 is controlled by the branch pipe 6a penetrating the heat amount and refrigerant amount adjustment container 5.
There is an amount of heat taken away from the body.

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 FIG. 7, a curve q4 represents a change in the amount of heat entering from the surrounding air with respect to the load, and a curve q5 represents a change in the amount of heat entering from the branch pipe 6a with respect to the load.
Also, the total amount of heat entering the refrigerant amount adjustment container 5 is q4
and q5, and this total amount of heat intrusion is represented by curve q6. A point g on the curve q6 indicates that there is no amount of heat entering the refrigerant amount adjustment container 5.

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 6a
By appropriately selecting the pipe diameter of the curve q6
It becomes possible to position the upper point g between points m and n, which are the normal load range.

In addition, in the examples shown in FIGS. 3, 4, and 6, the suction pipe 6 connecting the compressor 1 and the evaporator 4 is
The branch pipe 6a branched from the refrigerant amount regulating container 5 is passed through the refrigerant amount regulating container 5, and the purpose of this passage is to allow heat exchange between the branch pipe 6a and the refrigerant amount regulating container 5. Therefore, the branch pipe 6a 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 connects the compressor, the condenser, the throttling device, and the evaporator in an annular manner, connects the refrigerant amount adjusting container to a connecting position in the middle of the throttling device, and further includes: A branch pipe branched from a suction pipe connecting the compressor and the evaporator is disposed in the refrigerant amount regulating container for heat exchange. 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 branch pipe, which is a part of the suction pipe that connects the compressor and the evaporator, is disposed in the refrigerant amount adjustment container for heat exchange. By appropriately selecting the pipe diameter of the pipe, the amount of refrigerant that can be stored in the refrigerant amount adjustment container under the design load conditions can be arbitrarily selected. For this reason,
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 minimum load condition considered at the time of design. Furthermore, since no moving parts such as electromagnetic valves are required to adjust the amount of refrigerant, the refrigerant amount adjustment device is less likely to fail and is highly reliable.

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 7 is a sectional view showing another example of the refrigerant amount adjusting container, and FIG. 7 is an explanatory diagram showing the heat balance of the refrigerant amount adjusting container in one embodiment of the present invention. 1... Compressor, 2... Condenser, 3... Throttle device, 4... Evaporator, 5... Refrigerant amount adjustment container, 6...
... Suction pipe, 6a... Branch pipe.

Claims (1)

[Claims] 1. A compressor, a condenser, a throttle device, and an evaporator are each connected in a ring, a refrigerant amount adjustment container is connected in the middle of the expansion device, and the compressor and evaporator are connected to this refrigerant amount adjustment container. A refrigerant amount adjustment device in a refrigeration system, which has branch pipes branched from a suction pipe arranged for heat exchange.