JPH07111280B2 - Refrigeration cycle equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a refrigeration cycle apparatus using a mixed refrigerant, and as a temperature control device in a constant temperature bath or the like, the inside of the refrigerator is widely used from low temperature to normal temperature or from low temperature to high temperature. The present invention relates to a refrigeration cycle device capable of temperature control.

(Prior Art) Most conventional refrigerators use a single refrigerant, and the output temperature can be controlled only by controlling the capacity of the compressor, etc., and the controllable temperature range is extremely limited. It was a thing.

For this reason, in a constant temperature bath where various materials and parts are placed under various temperature atmospheres, and the temperature characteristics are inspected, when controlling the temperature inside the refrigerator, heating the electric heater etc. together with the refrigeration equipment as described above. It is usually used together with a container (see Japanese Patent Laid-Open No. 1-224638).

That is, a cooler unit for discharging cold air supplied from the refrigerating apparatus and a heater separately from the cooler section are installed in the thermostatic chamber, and when the temperature control below room temperature is required, the refrigerating apparatus and the heating unit are heated. A predetermined temperature is obtained by operating the heater and the heater at the same time, and on the other hand, when a high temperature above normal temperature is required, only the heater is operated to control the temperature.

(Problems to be Solved by the Invention) However, as long as the control means as described above is used, a heater is indispensable in the chamber of the constant temperature bath, and the installation space for the material to be tested and the like is reduced accordingly. Inevitably, at the same time, operating the heater in low temperature control and the like was also a waste of energy.

Therefore, the present applicant previously proposed a refrigeration system using a mixed refrigerant for the purpose of enabling temperature control over a wide range from low temperature to room temperature or from low temperature to high temperature only with the refrigeration system (Japanese Patent Laid-Open No. 60- 142162), which uses a non-azeotropic mixed refrigerant consisting of a low boiling point refrigerant and a high boiling point refrigerant as a refrigerant in the apparatus, and by storing an appropriate amount of the low boiling point refrigerant in a tank attached to the refrigeration apparatus The refrigerant mixing ratio in the refrigeration cycle is changed, and thereby the refrigerating output is adjusted so that the output temperature can be changed. However, even if such a refrigerating apparatus is used, the controllable range is insufficient as the temperature control apparatus for the constant temperature bath as described above, and improvement in this respect has been desired.

The present invention addresses the above situation and provides a refrigeration cycle apparatus capable of controlling a wide range of temperature in a constant temperature bath or the like, and further capable of achieving expansion of a storage space and energy saving during temperature control. As a problem, in particular, by developing a refrigeration cycle apparatus capable of controlling a wide range of temperatures from low temperature to normal temperature, and further from low temperature to high temperature by improving the refrigeration apparatus using the mixed refrigeration, and to make the refrigeration cycle apparatus compact. The purpose is to plan.

(Means for Solving the Problem) That is, the feature of the present invention that meets the above object is a refrigeration circuit using a non-azeotropic mixed refrigerant composed of a low boiling point refrigerant and a high boiling point refrigerant, and the compressor (1) From the low-boiling-point refrigerant outlet (3A) of the gas-liquid separator (3) to the gas-liquid separator (3) via the condenser (2), and the cascade condenser ( 4) and connected to the three-way solenoid valve (7),
The three-way solenoid valve (7) is connected between the second solenoid valve (11) and the second expansion valve (9) and the refrigerant liquid storage tank (6) so that they can be selectively connected and switched. One branching from the high boiling point refrigerant outlet (3B) of the gas-liquid separator (3) is the first
To the cascade condenser (4) via the expansion valve (8) of
The other is the second solenoid valve (11) and the second expansion valve (9).
To the evaporator (5), and the high boiling point refrigerant outlet (4B) of the cascade condenser (4) and the outlet of the evaporator (5) are connected to a confluence (C), and the confluence (C) is further connected. ) Is connected to the suction side of the compressor (1) via a refrigerant cooling coil (13) for cooling the refrigerant liquid reservoir tank (6), and the outlet of the refrigerant liquid reservoir tank (6) is provided with a capillary tube (14). ) And a third solenoid valve (12) are connected to the confluence point (C).

Further, the invention according to claim 2 is based on the above-mentioned constitution, and the pipe and the confluence point (C) between the compressor (1) and the condenser (2).
The pipe between the refrigerant cooling coil (13) and the four-way switching valve (16)
And the check valve (18) and the capillary tube (1) between the condenser (12) and the gas-liquid separator (13).
7) is provided in parallel, and the check valve (19) is provided in parallel with the second expansion valve (9) to enable the reverse cycle by switching the four-way switching valve (16). It is characterized in that the range of temperature control is further expanded.

In any of the above configurations, the invention according to claim 3 connects the discharge side of the compressor (1) and the refrigerant reservoir tank (6) with a pipe, and opens the pipe at a pressure higher than a predetermined pressure. By arranging (15) and the fourth solenoid valve (20) sequentially from the compressor (1) side, the overall size of the device can be made compact.

(Operation) In the refrigeration cycle apparatus of the present invention according to claim 1, the non-azeotropic mixed refrigerant discharged from the compressor (1) is separated into a high boiling point refrigerant and a low boiling point refrigerant by the gas-liquid separator (3). To be done. Then, the high-boiling-point refrigerant becomes a low temperature through the first expansion valve (8), after which heat exchange between the two refrigerants is performed in the cascade condenser (4), the high-boiling-point refrigerant is evaporated, and the low-boiling-point refrigerant is liquefied. By supplying this liquefied low boiling point refrigerant to the second expansion valve (9) and further to the evaporator (5) by switching the three-way solenoid valve (7), it is possible to control the temperature in the low temperature mode by the low boiling point refrigerant. Become.

Further, after the low boiling point refrigerant liquefied by the cascade condenser (4) is stored in the refrigerant liquid storage tank (6), the high boiling point refrigerant is discharged from the high boiling point refrigerant outlet (3B) of the gas-liquid separator (3) to the second
By supplying the second expansion valve (9) and the evaporator (5) through the electromagnetic valve (11), the temperature control in the normal temperature mode becomes possible.

Next, in the refrigeration cycle apparatus according to claim 2, a cycle similar to that of the refrigeration cycle apparatus according to claim 1 can be constructed by appropriately operating the four-way switching valve (16). Similar to the refrigeration cycle device, temperature control is performed in the low temperature mode and the normal temperature mode.

Further, by switching the four-way switching valve (16) from the normal temperature mode, a refrigeration cycle opposite to the conventional cycle is formed, and the high boiling point refrigerant is condensed in the evaporator (5) and the temperature in the high temperature mode is increased. It becomes possible to control.

Further, in the refrigeration cycle apparatus according to claim 3, the discharge pressure adjustment is performed when the high pressure gas refrigerant on the discharge side of the compressor (1) is opened above the fourth pressure by opening the fourth solenoid valve (20) only in the low temperature mode. The valve (15) is opened, and a part of the gas refrigerant can be guided to the refrigerant liquid storage tank (6) to ensure the safety of the device. Conventionally, as a safety measure, an expansion tank or the like is usually provided separately on the discharge side of the compressor (1), but in the refrigeration cycle apparatus according to the invention of claim 3, it is necessary to additionally provide the expansion tank or the like. Instead, the entire device can be made compact.

(Example) Hereinafter, the Example of this invention is described further based on drawing.

FIG. 1 is a piping system diagram showing an example of the refrigeration cycle apparatus according to claim 1. The refrigeration cycle device, for example,
A low boiling point refrigerant such as R13 and a high boiling point refrigerant such as R22 are used as a non-azeotropic mixed refrigerant, and as shown in the figure, a compressor (1), a condenser (2), a gas-liquid separation Bowl (3),
The cascade condenser (4), the evaporator (5), and the refrigerant reservoir tank (6) are connected by pipes.

The compressor (1), the condenser (2) and the gas-liquid separator (3) are sequentially connected by piping, and the low boiling point refrigerant outlet (3) of the gas-liquid separator (3) is connected.
A first solenoid valve (10) is installed in A), and a first expansion valve (8) is installed in the high boiling point refrigerant outlet (3B) of the gas-liquid separator (3). It is connected to (4). In addition to the above, the high boiling point refrigerant outlet (3B) is also connected to an evaporator (5) via a second electromagnetic valve (11) and a second expansion valve (9).

On the other hand, a low boiling point refrigerant outlet (4A) of the cascade condenser (4) is provided with a three-way solenoid valve (7), and one end of the three-way solenoid valve (7) is connected to the second expansion valve (9) through the second expansion valve (9). It is connected to the evaporator (5), and the other end of the three-way solenoid valve (7) is connected to the refrigerant liquid reservoir tank (6).

The refrigerant liquid storage tank (6) is characterized in that the refrigerant is stored in a liquid state, and has an advantage that the tank can be made smaller than a tank in which the refrigerant is stored in a gas state. A refrigerant cooling coil (13) for cooling the refrigerant is installed inside the refrigerant liquid storage tank (6), while a final complete countermeasure against the pressure increase in the tank (6) outside the same. As a safety valve (18) is provided. The outlet side of the refrigerant reservoir tank (6) is connected to the outlet side of the evaporator (5) via a capillary tube (14) and a third solenoid valve (12), and a confluence point (C) described later And is connected to the refrigerant cooling coil (13).

Here, the refrigerant cooling coil (13) serves to cool the inside of the refrigerant liquid reservoir tank (6) as described above by using the low temperature gas immediately before the suction of the compressor (1), and the evaporator (5). And the high boiling point refrigerant outlet (4B) of the cascade condenser (4) are merged into one, and the suction side of the compressor (1) is passed from this junction (C) via the refrigerant cooling coil (13). The pipe is connected to.

In the refrigeration cycle apparatus, since the low boiling point refrigerant has a very high pressure at room temperature, the refrigerant cooling coil (13)
A refrigerant return capillary tube (22) and an expansion tank (21) are provided on the outlet side of the compressor. On the other hand, the compressor (1) discharge side opens above the set pressure in order to suppress the pressure increase on the high pressure side at startup. A discharge pressure adjusting valve (15) is installed, and the discharge side of the compressor (1) is connected to the expansion tank (21) via the discharge pressure adjusting valve (15). It should be noted that the provision of the expansion tank (21) and the like in this way is a means that has been generally performed conventionally as a safety measure for this type of refrigeration system.

Therefore, the operation of the refrigeration cycle apparatus configured as described above will be described below. The apparatus shown in FIG. 1 can control the temperature from low temperature to normal temperature, but the operation method differs depending on the temperature. Here, the operation method will be described separately for the low temperature mode and the normal temperature mode.

First, in the low temperature mode, open the first solenoid valve (10) to
The second and third solenoid valves (11) and (12) are both closed, and the three-way solenoid valve (7) is switched to the direction shown by the solid line, and at the same time the first
Both the expansion valve (8) and the second expansion valve (9) are appropriately controlled.

The mixed refrigerant discharged from the compressor (1) is transferred to the condenser (2).
At this time, mainly only the high boiling point refrigerant is liquefied, and thereafter, mainly the low boiling point refrigerant from the low boiling point refrigerant outlet (3A) of the gas-liquid separator (3) and the high boiling point refrigerant outlet (3A) of the gas liquid separator (3) ( High boiling point refrigerants are mainly discharged from 3B). By the above-mentioned operation, after the high-boiling-point refrigerant of both refrigerants discharged from the gas-liquid separator (3) becomes low temperature and low pressure by the first expansion valve (8), both refrigerants are cascade condenser (4). In the heat exchange, the low boiling point refrigerant is deprived of heat and condensed, while the high boiling point refrigerant obtains heat and becomes a gas refrigerant.

The former, low boiling point refrigerant is further passed through the three-way solenoid valve (7) to the second
Adiabatic expansion is performed by the expansion valve (9), and then enters the evaporator (5) to evaporate, and the heat of evaporation is taken away, where a cooling action is performed. Then, to the cooling action by the low boiling point refrigerant, means such as capacity control of the compressor (1) which has been conventionally performed is added, and temperature control from low temperature to room temperature of about 0 ° C. becomes possible.

On the other hand, the latter high boiling point refrigerant merges with the former low boiling point refrigerant at the confluence point (C), and returns to the compressor (1) via the refrigerant cooling coil (13).

Next, to switch from low temperature mode to normal temperature mode,
First, among the operation operations in the low temperature mode, only the three-way solenoid valve (7) is switched in the direction of the dotted line in the figure. As a result, the low boiling point refrigerant outlet (4A) of the cascade condenser (4) communicates with the refrigerant liquid reservoir tank (6), and the low boiling point refrigerant is gradually stored in the refrigerant liquid reservoir tank (6). At this time, the high boiling point refrigerant flowing out of the cascade condenser (4) flows from the confluence point (C) through the refrigerant cooling coil (13) and then returns to the compressor (1). The inside of the tank (13) is cooled.

In the normal temperature mode operation, the first solenoid valve (10) is closed and the second solenoid valve (11) is opened when most of the low boiling point refrigerant is stored in the refrigerant reservoir tank (6), With the three-way solenoid valve (7) still switched to the dotted line, the first expansion valve (8) is fully closed and the second expansion valve (9) is appropriately controlled.

As a result, only the high-boiling point refrigerant circulates in the refrigeration cycle apparatus, and the high-boiling point refrigerant passes through the compressor (1) and the condenser (2) and then the high-boiling point refrigerant outlet of the gas-liquid separator (4). (3B), through the second solenoid valve (11), flows to the second expansion valve (9), then reaches the evaporator (5), and a predetermined cooling action is performed.

The cooling action by the high boiling point refrigerant is controlled to some extent by the capacity control of the compressor (1) and the like as described above.
It becomes possible to control the temperature at room temperature from 0 ° C to 10 ° C.

The normal temperature mode is switched to the low temperature mode by opening the third solenoid valve (12) for a few minutes and using the refrigerant in the cycle as a mixed refrigerant, and then operating the low temperature mode as described above.

When stopping the device, the first to third solenoid valves (1
0), (11), (12) are all opened, the three-way solenoid valve (7) is set to the position of the solid line, and the first and second expansion valves (8),
It is preferable to fully open both (9) to prepare for the next operation.

The above is the description of the refrigeration cycle apparatus capable of controlling the temperature from low temperature to normal temperature. Next, a refrigeration cycle apparatus capable of temperature control from low temperature to high temperature constructed based on the above refrigeration cycle apparatus is shown in FIG. Will be described with reference to.

This is the refrigeration cycle apparatus according to the invention of claim 2,
On the discharge side of the compressor (1) of the device shown in the figure, a four-way switching valve (1
6) is provided, and the discharge gas of the compressor (1) is supplied to the condenser (2) by switching the four-way switching valve (16).
On the other hand, it is also possible to supply in the direction of the evaporator (5). Specifically, the four-way switching valve (16) is provided between the compressor (1) and the condenser (2) and between the confluence (C) and the refrigerant cooling coil (13), and further, A check valve (18) is installed between the condenser (2) and the gas-liquid separator (3), and a capillary tube (17) is arranged in parallel with the check valve (18), while the second The check valve (19) is provided in parallel with the expansion valve (9).

Note that in FIG. 2, the same components as those shown in FIG. 1 are denoted by the same numbers as in FIG.

First, in the device shown in FIG. 2, when the four-way switching valve (16) is switched in the direction shown by the solid line, the refrigerant flows toward the condenser (2). At this time, the refrigerant flows to the capillary tube (17) and the reverse side. It does not pass through the stop valve (19),
Therefore, at this time, the device is substantially the same as the device shown in FIG.

Therefore, in the operation related to the low temperature mode and the normal temperature mode, the four-way switching valve (16) may be switched in the direction of the solid line, and otherwise the same operation as described with reference to FIG. 1 may be performed.

Therefore, the high temperature mode will be mainly described here. This operation in the high temperature mode is performed by circulating the high boiling point refrigerant, and normally, the low boiling point refrigerant is stored in the refrigerant reservoir tank (6).
It is preferable to continue to the room temperature mode stored in the above, other than that, for example, when operating in the high temperature mode from the beginning, the operation performed when switching from the low temperature mode to the room temperature mode is performed first, and the refrigerant liquid It is necessary to store the low boiling point refrigerant in the storage tank (6).

After that, the first and third solenoid valves (1
0) and (12) are both closed, the second solenoid valve (11) is opened,
Further, the three-way solenoid valve (7) is set to the position of the dotted line, and the first expansion valve (8) is closed, while the four-way switching valve (1
6) is switched to the dotted line direction and the second expansion valve (9)
Fully closed.

Then, this device becomes a refrigeration cycle device in the opposite direction to the conventional one, and the high boiling point refrigerant compressed by the compressor (1) first enters the evaporator (5).

Then, the evaporator (5) acts as a condenser, and a desired high temperature heat is obtained in the evaporator (5). After this,
The high boiling point refrigerant is passed through the check valve (19) to the second solenoid valve (1
1), flowing through the gas-liquid separator (3), adiabatically expanded by the capillary tube (17), evaporated by the condenser (2), and then, cooled by the refrigerant cooling coil (13) via the four-way switching valve (16). ), And returns to the compressor (1).

In this way, the refrigeration cycle apparatus according to claim 2 can widely control the temperature from low temperature to high temperature.

Next, the refrigeration cycle apparatus according to claim 3 makes more effective use of the refrigerant liquid storage tank (6) installed in the refrigeration cycle apparatus according to claim 1 or 2 described above. As shown in the figure, the expansion tank (21) and the like are removed, and instead, a pipe from the discharge side of the compressor (1) to the refrigerant liquid storage tank (6) is provided, and the pressure on the discharge side of the compressor (1) is provided in this pipe. With a discharge pressure adjusting valve (15) that opens when the temperature exceeds a certain value, and a fourth solenoid valve (20) that prevents the refrigerant from flowing backward from the refrigerant reservoir tank (6) to the discharge side of the compressor (1) Is. At the time of stop and operation in low temperature mode, open this fourth solenoid valve (20),
The high-pressure gas on the discharge side of the compressor (1) is appropriately guided to the refrigerant liquid storage tank (6). That is, in this case, the refrigerant liquid storage tank (6) is used as an expansion tank, which can ensure the safety of the apparatus. At this time,
It is important to keep the third solenoid valve (12) open so that the refrigerant contained in the refrigerant reservoir tank (6) enters the pipe through the capillary tube (14) and the third solenoid valve (12). return.

On the other hand, in the normal temperature mode and the high temperature mode, the fourth solenoid valve (20) is closed and the refrigerant liquid reservoir tank (6) is used for refrigerant storage as described above.

Although FIG. 3 shows the device applied to the device shown in FIG. 2, it may of course be applied to the device shown in FIG.

As described above, the refrigeration cycle apparatus according to the third aspect of the present invention is safe without an expansion tank and the like, and the entire apparatus is compact.

As described above, the refrigeration cycle apparatus according to the present invention can control a wide range of temperatures from low temperature to room temperature or from low temperature to high temperature, and thus is most suitable as a control device for a constant temperature bath, in which case space saving and energy saving can be achieved. Can be achieved.

(Effect of the invention) The present invention is configured as described above, and in the refrigeration cycle apparatus according to the invention of claim 1, the non-azeotropic mixed refrigerant discharged from the compressor is a high boiling point refrigerant and a high boiling point refrigerant in the gas-liquid separator. It is separated into the boiling point refrigerant, of which the high boiling point refrigerant becomes low temperature and low pressure through the first expansion valve, and then both refrigerants exchange heat with each other in the cascade condenser, after which the low boiling point refrigerant causes the three-way solenoid valve to operate. Is supplied to the evaporator from the second expansion valve via the second expansion valve to perform the cooling action by the low boiling point refrigerant, while switching the three-way solenoid valve to store the low boiling point refrigerant in the refrigerant reservoir tank,
After that, by operating another solenoid valve etc. to supply the high boiling point refrigerant to the second expansion valve and the evaporator behind it, the cooling action by the high boiling point refrigerant is performed, so a wide range from low temperature to normal temperature is achieved. It is possible to control the temperature of.

From this, the refrigeration cycle apparatus according to the invention of claim 1 is most suitable as a temperature control apparatus for a constant temperature bath that requires temperature control at room temperature or lower. In this case, a heater or the like is not required, and the interior space is expanded and energy is saved. Is achieved.

Further, the refrigeration cycle apparatus according to the invention of claim 2 can reverse the refrigeration cycle of the refrigeration cycle apparatus according to the invention of claim 1 by switching the four-way switching valve. In addition to the temperature control up to, it is also possible to control the temperature at high temperature, and it is most suitable as a temperature control device for a constant temperature bath that requires wide temperature control from low temperature to high temperature. Of course, also in this case, it is possible to achieve expansion of the constant temperature chamber space of the constant temperature chamber and energy saving.

Further, in the invention relating to claim 3, the compressor discharge side and the refrigerant liquid reservoir tank are connected by a pipe provided with a discharge pressure adjusting valve and a solenoid valve, so that the refrigerant liquid reservoir tank can be used as an expansion tank. Therefore, of course, it is safe even if the high-pressure side becomes higher than a predetermined pressure, and as a safety measure, it is not necessary to separately provide an expansion tank or the like, and the entire apparatus can be made compact and economically advantageous.

[Brief description of drawings]

FIG. 1 is a piping system diagram showing an example of the refrigeration cycle apparatus according to claim 1 of the present invention, and FIG. 2 is a piping system diagram showing an example of the refrigeration cycle apparatus according to claim 2 of the present invention. FIG. 3 is a piping system diagram showing an example of the refrigeration cycle apparatus according to claim 3 of the present invention. (1) …… Compressor, (2) …… Condenser, (3) …… Gas-liquid separator, (3A) …… Low boiling point refrigerant outlet, (3B) …… High boiling point refrigerant outlet, (4)… … Cascade condenser, (4A) …… Low boiling point refrigerant outlet, (4B) …… High boiling point refrigerant outlet, (5) …… Evaporator, (6) …… Refrigerant liquid storage tank, (7) …… Three-way solenoid valve , (8) …… first expansion valve, (9) …… second expansion valve, (10) …… first solenoid valve, (11) …… second solenoid valve, (12) …… Third solenoid valve, (13) …… Refrigerant cooling coil, (14) …… Capillary tube, (15) …… Discharge pressure adjusting valve, (16) …… Four way switching valve, (17) …… Capillary tube , (18) …… Check valve, (19) …… Check valve, (20) …… Fourth solenoid valve, (C) …… Confluence point.

Claims (3)

[Claims] 1. A refrigeration circuit using a non-azeotropic mixed refrigerant composed of a low boiling point refrigerant and a high boiling point refrigerant, wherein a gas-liquid separator (3) is connected from a compressor (1) through a condenser (2). Then, the low boiling point refrigerant outlet (3A) of the gas-liquid separator (3) is connected to the three-way solenoid valve (7) via the first solenoid valve (10), the cascade condenser (4), and the three-way solenoid valve (3). Second from valve (7)
Between the solenoid valve (11) and the second expansion valve (9) and the refrigerant liquid storage tank (6) are connected so as to be selectively switchable, and the high boiling point refrigerant of the gas-liquid separator (3) is connected. One branching from the outlet (3B) goes to the cascade condenser (4) via the first expansion valve (8) and the other goes to the evaporator via the second solenoid valve (11) and the second expansion valve (9). Connected to (5),
The high boiling point refrigerant outlet (4B) of the cascade condenser (4) and the outlet of the evaporator (5) are connected to a confluence point (C), and the confluence point (C) connects the refrigerant liquid reservoir tank (6). The refrigerant cooling coil (13) for cooling is connected to the suction side of the compressor (1), and the outlet of the refrigerant liquid storage tank (6) is connected to a capillary tube (14) and a third solenoid valve (12). A refrigeration cycle apparatus characterized in that it is connected to the confluence point (C) through 2. A pipe between a compressor (1) and a condenser (2) and a pipe between a confluence point (C) and a refrigerant cooling coil (13) are connected via a four-way switching valve (16). With the condenser (2)
A check valve (18) and a capillary tube (17) between the gas-liquid separator (3) and the gas-liquid separator (3), and a check valve (19) parallel to the second expansion valve (9). The four-way switching valve (1
The refrigeration cycle apparatus according to claim 1, wherein a reverse cycle is made possible by switching of 6). 3. A discharge pressure adjusting valve (15) and a fourth solenoid valve (which connect a discharge side of the compressor (1) and a refrigerant liquid storage tank (6) to each other by piping, and open the piping at a pressure equal to or higher than a predetermined pressure. 20)
The refrigeration cycle apparatus according to claim 1 or 2, wherein the compressors are sequentially arranged from the compressor (1) side.