JPH10153362A - Refrigerating plant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To return refrigerator oil with high efficiency where refrigerator oil whose compatibility with a refrigerant tends to be separated from the refrigerant especially in an evaporator whose temperature tends to be low and the separated refrigerator oil must be returned to a compressor by way of a refrigerant pipeline and an accumulator provide in the refrigerant pipeline. SOLUTION: Solenoid valves 17 and 23 are temporarily closed while solenoid valves 19 and 21 are opened. The whole amount of refrigerant to be fed to an evaporator 1 from a condenser 7 is temporarily sent to an accumulator 3 where the refrigerant separated in a double layer inside the accumulator 3 is mixed with a refrigerator oil and it is sent energetically to a compressor 5 using the high pressure of the fed refrigerant. Even in a refrigerating plant where the compressor 5 is laid out above the evaporator 1, the refrigerator oil can be returned easily by surface tensile force by using a pipe 26 with a groove in a refrigerant pipeline 13A from the evaporator up to the compressor 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a refrigeration apparatus,
More specifically, the present invention relates to a structure for returning refrigeration oil separated from a refrigerant to a compressor.

[0002]

2. Description of the Related Art Generally, a refrigeration system (in this specification, a concept including a refrigeration system) is used in a wide range of fields such as cooling inside a showcase and a refrigerator.

FIG. 4 shows a general refrigerant circuit diagram of such a refrigeration system. That is, the refrigerant evaporated in the evaporator 1 is
The refrigerant is sent to the accumulator 3 through the refrigerant pipe 13, and is temporarily stored until the refrigerant liquid that has not completely evaporated out of the refrigerant evaporates. Only the evaporated refrigerant gas is sent to the compressor 5 and is compressed to be a high-temperature and high-pressure refrigerant. Gas. The high-temperature and high-pressure refrigerant gas is cooled by exchanging heat with surrounding air in the condenser 7,
Condense. The condensed refrigerant liquid is sent to the dryer 9 and excess water present in the refrigerant is adsorbed by an adsorbent such as zeolite. After that, the refrigerant flows into the capillary tube 1
The pressure is reduced by passing through the evaporator 1, and then sent to the evaporator 1.

[0004] As a refrigerant, H does not destroy the ozone layer.
FC (hydroflurocarbon) based refrigerant (for example, HF
C-134a) is to be used. Also,
In the refrigerating device, refrigerating machine oil used for lubrication of the compressor 5 and the like is used in a state of being mixed with and melted by the refrigerant.
As the refrigerating machine oil when an HFC-based refrigerant is used, it is usual to use, for example, an ester, PAG (polyalkylene glycol oil) or the like as the refrigerating machine oil compatible with the refrigerant.

[0005] However, these refrigerating machine oils are highly hygroscopic and deteriorate due to the presence of moisture to generate sludge. This sludge adheres to the capillary tube 11 and the like, and separates the flow of the refrigerant, so that the cooling performance of the refrigerating apparatus is likely to be reduced. Therefore, in order to operate the refrigeration apparatus stably, it is necessary to control water, impurities, and the like that cause sludge to a low level. Also, in the service work in the market, it is necessary to control moisture, impurities, and the like to a low level, and the workability is much worse than the conventional work.

On the other hand, conventional refrigeration oils (alkylbenzene oil and mineral oil) used in conventional refrigerants (such as R22) that are not HFC-based refrigerants are less controlled than refrigeration oils that are more compatible with the HFC-based refrigerants. There was no need to be strict. For this reason, it is desirable that conventional refrigeration oil can be used if possible.

[0007]

However, if a refrigerating machine oil having poor compatibility with the refrigerant is used, the refrigerant and the refrigerating machine oil are easily separated in the refrigerant circuit, so that the refrigerating machine oil hardly returns to the compressor. In particular, the separated refrigerating machine oil tends to hardly come out of the accumulator 3 after being accumulated in the accumulator 3. For this reason, the compressor 5
The amount of the refrigerating machine oil returned to is smaller, and the possibility of causing the compressor 5 to run out of oil increases.

The present invention has been made to solve the above problems, and has as its object to provide a refrigeration apparatus that can efficiently return refrigeration oil accumulated in an accumulator to a compressor.

In some cases, the compressor is located above the evaporator, in which case the refrigerating machine oil flowing from the evaporator to the compressor must flow against gravity. For this reason, the fluidity deteriorates, and the amount returned to the compressor further decreases. In order to prevent this, another object of the present invention is to provide a refrigeration apparatus that can easily return refrigeration oil to the compressor even when the compressor is located above the evaporator. Aim.

[0010]

In order to achieve the above object, a first aspect of the present invention is to compress a refrigerant gas evaporated by an evaporator by a compressor sent through an accumulator to a high-temperature and high-pressure refrigerant gas. A refrigerant flow path for returning the refrigerant condensed by heat exchange with the surrounding air in the condenser to the evaporator again via the capillary tube, wherein refrigerant and refrigerating machine oil for lubricating the compressor are mixed. In the refrigerating apparatus, a bypass pipe for sending refrigerant to an accumulator from a refrigerant pipe from a compressor to a capillary tube, and a valve device for temporarily sending the entire amount of refrigerant from the compressor to the capillary tube to an accumulator are provided. Is a refrigeration apparatus.

According to a second aspect of the present invention, the bypass pipe connects a refrigerant pipe on the downstream side of the condenser with a refrigerant flow path on the upstream side of the accumulator. A first solenoid valve provided on the downstream side of the refrigerant pipe and downstream of the connection with the bypass pipe, a second solenoid valve provided on the upstream side of the bypass pipe, and a downstream side of the bypass pipe A third solenoid valve provided on the upstream side of the accumulator, a fourth solenoid valve provided on the upstream side of a connection portion with the bypass pipe, and temporarily the first and fourth solenoid valves. 2. A refrigerating apparatus according to claim 1, further comprising control means for closing said electromagnetic valve and opening said second and third electromagnetic valves at the same time.

According to a third aspect of the present invention, the bypass pipe connects the refrigerant pipe on the downstream side of the condenser with a lower portion in the main body of the accumulator, and the valve device is connected to the downstream side of the condenser. A first solenoid valve provided on the downstream side of the connection portion with the bypass pipe, a second solenoid valve provided on the upstream side of the bypass pipe, and provided on the downstream side of the bypass pipe. The third solenoid valve, the fourth solenoid valve provided in the refrigerant pipe on the upstream side of the accumulator, and simultaneously closing the first and fourth solenoid valves, simultaneously with the second and third solenoid valves 2. The refrigeration apparatus according to claim 1, comprising control means for opening the refrigeration apparatus.

According to a fourth aspect of the present invention, the refrigerant gas evaporated by the evaporator is further compressed by a compressor sent through an accumulator into high-temperature and high-pressure refrigerant gas, and heat-exchanged with ambient air by a condenser. In the refrigerating apparatus, comprising a refrigerant flow path for returning the condensed refrigerant to the evaporator again via the capillary tube, wherein the refrigerant and the refrigerating machine oil for lubricating the compressor are mixed, and the compressor is located above the evaporator. A refrigeration apparatus characterized in that a grooved pipe is used for part or all of a refrigerant pipe from an evaporator to a compressor.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. The evaporator 1 in which the refrigerant liquid evaporates and supplies cold heat is connected to the accumulator 3 via the refrigerant pipe 13A (26). Accumulator 3
Is a container for temporarily storing and evaporating the refrigerant liquid that has not been completely evaporated by the evaporator 1. The accumulator 3 is connected via a refrigerant pipe 13B to a compressor 5 which compresses the refrigerant gas into high-temperature and high-pressure refrigerant gas. The compressor 5 is connected via a refrigerant pipe 13C to a condenser 7 that cools a high-temperature and high-pressure refrigerant gas by air. The condenser 7 has a refrigerant pipe 13
Capillary tube 11 for depressurizing the refrigerant liquid via D
Connected to. The dryer 9 is provided in the middle of the refrigerant pipe 13D. In addition, the capillary tube 11
Is connected to the evaporator 1 via the refrigerant pipe 13E.

[0015] Further, an HFC-based refrigerant having a low risk of destruction of the ozone layer is used as the refrigerant, and a conventional refrigeration oil which has poor compatibility with this refrigerant but does not require strict control is used as the refrigeration oil. You.

The refrigerant pipe 13D on the downstream side of the condenser 7 branches into a bypass pipe 15 and is connected to the refrigerant pipe 13A on the upstream side of the accumulator 3. A first solenoid valve 17 is provided in the refrigerant pipe 13 on the downstream side of the condenser 7 and on the downstream side of the connection with the bypass pipe 15. A second solenoid valve 19 is provided upstream of the bypass pipe 15. Further, a third solenoid valve 21 is provided downstream of the bypass pipe 15. Further, a fourth solenoid valve 23 is provided on the refrigerant pipe 13 </ b> A (26) on the upstream side of the accumulator 3, on the upstream side of the branch portion with the bypass pipe 15. These four solenoid valves 17, 1
9, 21 and 23 are controlled by the control device 25, and temporarily control the first and fourth solenoid valves 17 and 23 to close and the second and third solenoid valves 19 and 21 to open.

Hereinafter, the operation of the bypass pipe 15 of this embodiment will be described.

First, the refrigerant liquid evaporates in the evaporator 1 to become a refrigerant gas. At this time, heat is taken off as heat of vaporization, and a cooling function is performed. The evaporated refrigerant gas is supplied to the accumulator 3
And the refrigerant liquid contained in the refrigerant gas and not completely evaporated is temporarily stored. The stored refrigerant liquid evaporates and becomes refrigerant gas. By temporarily storing the refrigerant liquid and evaporating the refrigerant gas to the compressor 5, the refrigerant liquid can be prevented from directly entering the compressor 5 and compressing the liquid. The refrigerant gas from the accumulator 3 is compressed by the compressor 5 and becomes a high-temperature and high-pressure refrigerant gas. The high-temperature and high-pressure refrigerant gas exchanges heat with surrounding air in the condenser 7 and is cooled. The cooled and condensed refrigerant liquid is decompressed through the capillary tube 9. The decompressed refrigerant liquid is sent to the evaporator 1 again.

The refrigerant exiting the compressor 5 contains refrigerating machine oil used for lubricating the compressor 5 and is mixed therewith. This refrigerating machine oil has poor compatibility with the refrigerant, and while flowing through the refrigerant circuit, that is, the refrigerant pipe 13, a part of the refrigerating machine oil is separated from the refrigerant. When the amount of refrigerating machine oil discharged from the compressor 5 increases, the amount of refrigerating machine oil inside the compressor 5 decreases.

For example, at the time of the defrosting operation of the refrigerating device or at the time of turning off the thermostat, the control device 25 temporarily closes the first and fourth solenoid valves 17 and 23, and at the same time, simultaneously controls the second and third solenoid valves 19 and An instruction to open 21 is issued. Thereby, the flow of the refrigerant that has been flowing from the condenser 7 to the dryer 9, the capillary tube 11, and the evaporator 1 is stopped, and the entire amount of the refrigerant is sent to the inside of the accumulator 3 through the bypass pipe 15.

As a result, the inside of the accumulator 3 is stirred by the high-pressure refrigerant gas,
The refrigerant liquid and the refrigerating machine oil, which have been separated into two layers, are dispersed and mixed with each other. The mixed and evaporated refrigerant and refrigerating machine oil are returned to the compressor 5 by the supplied high-pressure refrigerant gas.

After a certain period of time has passed and the refrigerating machine oil stored in the accumulator 3 has been returned to the compressor 5, the control device 25 sets the second and third solenoid valves 19, 21
And at the same time, the first and fourth solenoid valves 17 and 23 are opened.

Since the first and fourth solenoid valves 17 and 23 are closed while stirring the inside of the accumulator 3 in this manner, the stirring causes the refrigerant pipes 13C and 13C to close.
Sludge generated in D can be prevented from flowing to the capillary tube 11 and causing clogging. The generated sludge is settled or collected by a strainer (not shown) while the predetermined time has elapsed. In addition, it is possible to simultaneously prevent the refrigerant from the bypass pipe 15 from flowing back to the evaporator 1.

As shown in FIGS. 1B and 1C, a refrigerant pipe 13A from the evaporator 1 to the accumulator 3
The grooved tube 26 is used.

The grooved tube has a wavy inner peripheral surface in cross section (FIG. 1 (B)), and each groove 27 forming a wavy shape is spirally formed (FIG. 1 (C)). Various shapes are possible for the groove 27, and the groove 27 is flat (FIG. 2).
(A)) or one in which both the valley 29 and the top 31 are curved (FIG. 2B).

The operation of the groove 27 of this embodiment will be described below.

That is, the viscosity of the refrigerating machine oil separated from the refrigerant in the low-temperature evaporator 1 increases and the fluidity deteriorates. In addition, the compressor 5 is located above the evaporator 1 and the refrigerating machine oil is opposed to gravity. Even when it is necessary to flow, the refrigeration oil 33 (FIGS. 1B and 1C) penetrates between the grooves 27 by using the grooved pipe 26 as the refrigerant pipe 13 and obtains a large surface tension. The refrigerating machine oil 33 resists gravity due to the large surface tension as well as the flow and pressure difference of the refrigerant gas, and can easily return to the compressor 5.

(Other Embodiments) In the above embodiment, the third solenoid valve 21 is provided on the downstream side of the bypass pipe 15. However, in other embodiments, a check valve is provided instead of the solenoid valve 21. It is also possible to use valves. However, in order to completely prevent leakage of the bypassed refrigerant, the solenoid valve 21 is more advantageous.

Further, in the above embodiment, four solenoid valves 17, 19, 21, and 23 are used as the valve mounting values. However, in other embodiments, it is not necessary to use four solenoid valves. , The entire amount of the refrigerant flowing from the condenser 7 to the evaporator 1 is temporarily sent to the accumulator 3 and the compressor 5
Any configuration may be used as long as it is a valve device that can be returned to.

In the above embodiment, the groove 27 of the grooved tube 26 has been described as being formed in a spiral shape. However, in other embodiments, the groove 27 need not necessarily be formed in a spiral shape. It can be formed linearly in the axial direction.

In the above embodiment, the grooved tube 2
6 is a refrigerant pipe 1 from the evaporator 1 to the accumulator 3
However, in other embodiments, it is possible to use only a part near the evaporator 1 instead of all. That is, it is possible to provide the grooved pipe only in a portion where the refrigerating machine oil flows against gravity.

In the above embodiment, the bypass pipe 15 is connected to the refrigerant pipe 13 on the upstream side of the accumulator 3, but in other embodiments, the bypass pipe 15 is directly connected to the lower part in the main body of the accumulator 3. It may be connected.

That is, as shown in FIG. 3, a refrigerant pipe 13-1 from the evaporator 1 is connected and opened above a container 35 constituting the main body of the accumulator 3. Further, a refrigerant pipe 13-5 for connecting to the compressor 5 is connected to the bottom of the container 35 constituting the main body. A pipe 37 projecting upward into the container 35 is connected to this connection portion. A baffle plate 39 is provided further above the tip of the pipe 37. The baffle plate 39 is provided with a large number of holes 41 and is designed so that the refrigerant liquid contained in the refrigerant sent from above does not flow directly into the pipe 37. And the bypass pipe 15
Is connected near the bottom of the container 35.

The refrigerant gas evaporated by the evaporator 1 flows into the accumulator 3 from the upper portion through the refrigerant pipe 13-1. The refrigerant gas, which has not been completely evaporated, is contained in the refrigerant gas. After being once caught in 39, it falls downward through the hole 41. The dropped refrigerant liquid is temporarily stored around the pipe 37. The accumulated refrigerant liquid 43 evaporates gradually and enters from the tip of the pipe 37 and returns to the compressor 5 through the refrigerant pipe 13-5. At this time,
The separated refrigerating machine oil also accumulates around the pipe. The accumulated refrigerating machine oil 45 is separated into the refrigerant liquid 43 and roughly two layers.

The refrigerant liquid 43 and the refrigeration oil 45
On the other hand, the high-temperature and high-pressure refrigerant sent through the bypass pipe 15 is blown directly from near the bottom of the container 35. Thereby, the refrigerant liquid 43 and the refrigerating machine oil 45 are efficiently stirred, and the evaporation is promoted. The evaporated refrigerant and refrigerating machine oil are returned to the compressor 5 through the pipe 37 by the force of the high-pressure refrigerant that is continuously blown.

The positions of the four solenoid valves not shown in FIG. 3 are the same as those in FIG. 1A.

[0037]

As described above, according to the first to fourth aspects of the present invention, the high-pressure refrigerant from the condenser is sent to the accumulator by the bypass pipe, whereby the inside of the accumulator can be agitated. The refrigerant and the refrigerating machine oil, which have been separated in the above, are alternately dispersed and mixed, whereby the refrigerant liquid temporarily stored in the accumulator evaporates to become refrigerant gas and is sent to the compressor side. Machine oil is also sent to the compressor at the same time and can be easily returned to the compressor.

Further, by the high-pressure refrigerant sent,
It is possible to quickly and vigorously return the mixed and evaporated refrigerating machine oil in the accumulator to the compressor.

According to the second and third aspects of the present invention, there is a possibility that sludge in the refrigerant pipe is temporarily generated by stirring the accumulator, but since the first and fourth solenoid valves are closed, This prevents the sludge from being sent to the capillary tube and clogging. In addition, by temporarily sending the refrigerant, the time during which the refrigeration apparatus degrades in performance can be shortened.

According to the third aspect of the present invention, the high-pressure refrigerant can be directly sent to the lower portion of the inside of the main body of the accumulator, and the inside of the accumulator can be stirred more positively. Can be more positively mixed.

According to the fourth aspect of the present invention, the refrigerating machine oil can return to the compressor against gravity due to the surface tension by the action of the grooved tube.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention, in which (A) is an entire refrigerant circuit diagram, (B) is a cross-sectional view taken along line BB of (A),
(C) is a side view showing a part of (B) cut away.

FIG. 2 (A) is an enlarged partial perspective view of the inside of FIG. 1 (C),
(B) is a figure which shows the modification of (A).

FIG. 3 is an enlarged perspective view showing another embodiment, in which an inside of an accumulator attached to a refrigerant circuit equivalent to the refrigerant circuit of FIG. 1A is cut away.

FIG. 4 is a refrigerant circuit diagram of a conventional refrigeration apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Evaporator 3 Accumulator 5 Compressor 7 Condenser 9 Dryer 11 Capillary tube 13 Refrigerant pipe 15 Bypass pipe 17, 19, 21, 23 Solenoid valve 24 Controller (control means) 26 Grooved pipe 27 Groove

Claims (4)

[Claims] 1. A refrigerant gas evaporated by an evaporator is compressed by a compressor sent through an accumulator into high-temperature and high-pressure refrigerant gas, and the refrigerant condensed by exchanging heat with surrounding air in a condenser is passed through a capillary tube. Refrigeration system that has a refrigerant flow path that returns to the evaporator again via the refrigerant, and in which a refrigerant and a refrigerating machine oil for lubricating the compressor are mixed, sends the refrigerant from the refrigerant flow path from the compressor to the capillary tube to the accumulator A refrigeration system comprising: a bypass pipe; and a valve device for temporarily sending the entire amount of refrigerant flowing from the compressor to the capillary tube to an accumulator. 2. The bypass pipe connects a refrigerant pipe downstream of a condenser and a refrigerant pipe upstream of an accumulator, and the valve device is a refrigerant pipe downstream of the condenser. A first solenoid valve provided downstream of the connection with the bypass pipe, a second solenoid valve provided upstream of the bypass pipe, and a third solenoid valve provided downstream of the bypass pipe A valve,
A fourth solenoid valve, which is a refrigerant pipe on the upstream side of the accumulator and is provided on the upstream side of the connection with the bypass pipe, temporarily closes the first and fourth solenoid valves, and simultaneously sets the second and fourth solenoid valves. 2. The refrigeration apparatus according to claim 1, further comprising control means for opening the three solenoid valves. 3. The bypass pipe connects a refrigerant pipe downstream of the condenser with a lower part in the main body of the accumulator, and the valve device is a refrigerant pipe downstream of the condenser and is a bypass pipe. A first solenoid valve provided downstream of the connection with the pipe, a second solenoid valve provided upstream of the bypass pipe, and a third solenoid valve provided downstream of the bypass pipe When,
A fourth solenoid valve provided in the refrigerant pipe on the upstream side of the accumulator, and control means for temporarily closing the first and fourth solenoid valves and simultaneously opening the second and third solenoid valves. The refrigeration apparatus according to claim 1, wherein: 4. The refrigerant gas evaporated by the evaporator is compressed by a compressor sent through an accumulator into high-temperature and high-pressure refrigerant gas, and the refrigerant condensed by exchanging heat with surrounding air by a condenser is passed through a capillary tube. A refrigerant passage for returning to the evaporator again through the evaporator, wherein the refrigerant and the refrigerating machine oil for lubricating the compressor are mixed, and the compressor is located above the evaporator. Some or all of the refrigerant piping,
A refrigeration apparatus using a grooved tube.