JP2006098050A - Refrigeration air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To restrain sludge from being deposited in an inside of a refrigerant pipe constituting a refrigeration air conditioner for a refrigerator, an air conditioner or the like, and to enhance thereby operation reliability for the refrigeration air conditioner. <P>SOLUTION: This refrigeration air conditioner provided with a refrigerant circuit constituted of a compressor, a condenser, a contraction element and an evaporator has a control means for adding a refrigerator oil into an inlet or a midway of the condenser. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an inner wall of a refrigerant pipe of a device that generates a low temperature or a high temperature by condensing and evaporating a refrigerant such as a refrigerator or an air conditioner (hereinafter collectively referred to as a “refrigeration air conditioner”). The present invention relates to the improvement of the operation reliability of the refrigeration air conditioner with respect to the suppression of sludge adhesion (especially the inner wall of the pipe of the condenser), the heat exchanger refrigerant circuit, and the like.

  An example of a flow sheet of a refrigerant circuit of a conventional refrigeration air conditioner is shown in FIG. In the figure, 1 is a compressor, 2 is a condenser, 3 is a throttle element (for example, a nozzle, needle valve, etc.), 4 is an evaporator, and 5 is a sludge separator that captures sludge, and the refrigerant evaporates in this circuit. / Condensation is cycled repeatedly, thereby generating low or high temperatures. The sludge separator 5 is composed of, for example, a filter incorporating a fine wire mesh or the like, for example, a sludge catcher in which a metal processing oil film is formed on the surface in contact with the refrigerant disclosed in JP-A-9-145203.

  Next, the flow of the refrigerant will be described with reference to the drawings. In FIG. 11A, the arrows indicate the refrigerant flow. The refrigerant gas compressed to high temperature and high pressure by the compressor 1 flows into the condenser 2 and is liquefied by exchanging heat with air or the like to become high temperature and high pressure refrigerant liquid. The refrigerant liquid is decompressed by the throttle element 3 to become a low-temperature and low-pressure gas-liquid two-phase refrigerant, flows into the evaporator 4, heat-exchanges with air, gasifies to generate a low temperature, and then enters the compressor 1. Return. The refrigerating machine oil (or lubricating oil) is discharged together with the high-temperature and high-pressure refrigerant gas from the compressor 1, moves together with the refrigerant while partially dissolving in the refrigerant liquid liquefied in the condenser 2, and enters the throttle element 3 and the evaporator 4. Inflow. In the evaporator 4, the refrigerating machine oil is partly separated from the refrigerant liquid to be gasified, moves together with the refrigerant liquid and the refrigerant gas, and finally returns to the compressor 1 together with the refrigerant gas.

  The dissolution characteristic of the refrigerator oil in the refrigerant liquid in the condenser 2 is determined by the mutual dissolution characteristic corresponding to the combination of the refrigerant and the refrigerator oil. For example, in the case of a combination of a hydrofluorocarbon-based refrigerant that has been used recently instead of a hydrochlorofluorocarbon-based refrigerant and a refrigerating machine oil composed of a synthetic oil such as mineral oil or hard alkylbenzene oil, the mutual solubility decreases. That is, as the mutual solubility decreases, the position in the condenser 2 where all the refrigerating machine oil is dissolved in the refrigerant liquid moves downstream.

  In general, the deterioration of refrigerating machine oil progresses faster as the temperature is higher, and occurs more frequently at, for example, a sliding portion that becomes hot due to frictional heat in the compressor 1. Further, the additive added to the refrigerating machine oil is similarly thermally deteriorated. Such a deteriorated product is generally called sludge, and is present in the refrigerant and the refrigerating machine oil floating or dissolved. Polyester oil, polyether oil, and the like have low thermal stability and chemical stability against moisture and air, and when such oil is used, sludge is often generated. These sludges are discharged from the compressor 1 together with the refrigerant gas and the refrigerating machine oil, and flow into the condenser 2 and the throttle element 3. Since the throttle element 3 is composed of a capillary tube, a needle valve, or the like having a small channel cross-sectional area, it is likely to cause a channel blockage due to sludge. In the case of a needle valve, the flow passage cross-sectional area changes greatly, so that stagnation occurs in the flow and sludge tends to adhere. In such a situation, the flow resistance increases, the refrigerant circulation rate decreases, and the refrigerating capacity decreases. For this reason, the sludge is captured by the sludge separator 5 to prevent the sludge from flowing out to the throttle element 3.

  Next, a process in which sludge adheres to the inner wall of the pipe will be described. FIG. 11B is a graph schematically showing the behavior of the refrigerant liquid, the refrigerating machine oil, and the sludge in the condenser 2. In the graph, the horizontal axis represents the position in the refrigerant pipe of the condenser 2, and in the figure, point A is the condenser inlet and point B is the condenser outlet. The vertical axis represents the flow rate ratio of the refrigerating machine oil or sludge to the refrigerant liquid. Lines 10 and 11 indicate the saturation concentration of the refrigerating machine oil and sludge with respect to the refrigerant liquid, and curves 12 and 13 indicate the flow rate ratios of the refrigerating machine oil and sludge with respect to the refrigerant liquid, respectively.

  Therefore, the differences 14 and 15 indicated by the arrows mean the flow rate ratios of the refrigerating machine oil and sludge not dissolved in the refrigerant liquid to the refrigerant liquid, respectively, and the arrows at point C (the point where all the refrigerating machine oil dissolves in the refrigerant liquid). The difference 16 indicated by is the sludge deposition rate with respect to the refrigerant liquid, that is, the amount of sludge corresponding to 16 is deposited. In addition, the sludge currently demonstrated using 10-16 is a sludge which has solubility to refrigerating machine oil.

  At the condenser inlet (point A), the refrigerant gas discharged from the compressor and the refrigerating machine oil flow. The refrigerator oil contains suspended solid sludge and dissolved sludge. Refrigerating machine oil generally has a strong interaction with the wall of the refrigerant pipe due to its inherent physical properties, particularly stronger than sludge and refrigerant liquid, and as a result, tends to flow along the inner wall of the refrigerant pipe.

The compressed refrigerant gas starts condensing in the condenser to generate a refrigerant liquid phase. As the refrigerant gas undergoes a phase change to the refrigerant liquid, the ratio of the refrigerant liquid increases, and refrigeration oil and sludge are dissolved in the refrigerant liquid. Accordingly, the flow rate ratios 12 and 13 of the refrigerating machine oil and the sludge to the refrigerant liquid both rapidly decrease. At this time, both the refrigerating machine oil and the sludge are dissolved in the refrigerant liquid, but remain in an undissolved state only as much as the saturated concentration as follows:
(Refrigerator oil)
(Undissolved refrigerator oil amount 14) = (Refrigerator oil amount 12) − (Refrigerator oil saturation concentration 10)
(Sludge)
(Undissolved sludge amount 15) = (sludge amount 13) − (sludge saturation concentration 11).

Furthermore,
(Saturated concentration of refrigerating machine oil 10)> (saturated concentration of sludge 11),
That is, sludge cannot be dissolved so much in the refrigerant liquid as compared with refrigeration oil,
(Undissolved refrigerating machine oil amount 14) <(Undissolved sludge amount 15),
That is, when the amount of sludge that can be precipitated without dissolving in the refrigerant liquid is larger in the sludge than in the refrigeration oil, the refrigerating machine oil phase that exists independently of the refrigerant liquid (that is, it cannot be completely dissolved in the refrigerant liquid, The sludge is dissolved in a concentrated state in a refrigerator oil phase that exists as a liquid phase.

  However, when the point at which all the refrigerating machine oil dissolves in the refrigerant liquid (point C) is reached, the refrigerating machine oil phase cannot exist independently, and the sludge dissolved therein has a sludge deposition ratio of 16 to the refrigerant liquid. It precipitates only and becomes a fine solid or high-viscosity liquid precipitation sludge, which remains on the inner wall surface of the refrigerant pipe and adheres. At this time, solid sludge floating around is also caught and adhered by the binder action of the precipitated sludge. By repeating the above phenomenon, the sludge dissolved in the refrigerating machine oil adheres to the inner wall of the pipe, and grows into a large sludge, which eventually leads to blockage of the flow path. In addition, sludge that grows very large is peeled off by the shearing force of the flow of the refrigerant liquid, and may float and flow as large particles.

  There are many sludges having a saturation concentration relationship as described above with respect to the refrigerant liquid. For example, sludge derived from thermal deterioration of an additive added to refrigerating machine oil is one example. In the case of this sludge, as the deterioration progresses, it becomes a highly viscous liquid and solid, and the saturation concentration with respect to the refrigerant liquid also decreases.

  Furthermore, if there is any sludge that precipitates from the refrigerating machine oil, solid sludge that floats due to the binder action is involved, and if the sludge adheres to the inner wall after precipitation, it grows into a large deposit as the operating time of the device elapses. To do.

  The solid sludge that behaves as described above and the sludge that dissolves in the oil are not limited to sludge discharged from the compressor, and reaction products and dust generated by the reaction with the refrigerant pipe material are solid sludge. Residual processing oil or the like is considered to behave similarly as sludge dissolved in oil.

  As described above, the sludge deposited from the refrigerating machine oil grows into a large deposit (or sludge growth product) and can eventually lead to blockage of the flow path. In addition, clogging of the sludge separator due to exfoliated particles generated by exfoliating sludge that has grown greatly increases the flow path resistance, reduces the circulation amount of the refrigerant, and reduces the refrigerating capacity. That is, even when a sludge separator is used, the clogging occurs at a relatively early time.

  The present invention has been made in order to solve the above-described problems, and suppresses sludge from adhering to the refrigerant piping constituting the refrigerating and air-conditioning apparatus such as a refrigerator and an air conditioner. The purpose is to improve the operation reliability of the device.

  In one aspect of the first aspect of the present invention, in the refrigerating and air-conditioning apparatus including the refrigerant circuit configured by the compressor, the condenser, the throttle element, and the evaporator, the refrigerating machine oil is added to the inlet or the middle of the condenser. There is provided a refrigerating and air-conditioning apparatus characterized by having a control means. In this refrigeration air conditioner, the control means preferably makes the amount of the refrigeration oil flowing in the condenser larger than the amount of the refrigeration oil that can be dissolved in the refrigerant liquid.

  Furthermore, in another aspect of the first aspect, the present invention provides a method for operating a refrigeration air conditioner including a refrigerant circuit configured by a compressor, a condenser, a throttle element, and an evaporator. Control is performed so that the amount of refrigerating machine oil flowing in the condenser is larger than the amount of refrigerating machine oil that can be dissolved in the refrigerant liquid flowing in the condenser.

  In one aspect of the second aspect of the present invention, in a refrigerating and air-conditioning apparatus including a refrigerant circuit constituted by a compressor, a condenser, a throttle element, and an evaporator, refrigerating machine oil is added to the inlet or in the middle of the condenser. The control means is characterized in that the amount of refrigerating machine oil flowing in the condenser is temporarily larger than the amount of refrigerating machine oil that can be dissolved in the refrigerant liquid. A refrigeration air conditioner is provided.

  Furthermore, in another aspect of the second aspect, the present invention provides a method for operating a refrigeration air conditioner including a refrigerant circuit constituted by a compressor, a condenser, a throttle element, and an evaporator. Using the additional control means for the refrigerating machine oil, the amount of the refrigerating machine oil flowing in the condenser is temporarily made larger than the amount of the refrigerating machine oil that can be dissolved in the refrigerant liquid.

  As such a control means, an oil sump container for refrigerating machine oil is provided between the compressor and the condenser, and the refrigerating machine oil contained in the oil sump container has an oil injection pipe connected to the inlet or in the middle of the condenser, and It is added to the condenser via a valve provided in the middle of the injection pipe. This addition is performed by a controller that controls the opening and closing of the valve. This oil reservoir is not an independent container, but may be an oil reservoir that stores refrigeration oil in the high-pressure space of the compressor.

  Another control means used in the second aspect of the present invention is a compressor driven by a rotating machine, and the amount of refrigerating machine oil discharged per unit refrigerant flow rate when the rotating machine exceeds the normal rotational speed. The compressor having an increasing oil discharge characteristic is used, and the addition of the refrigerating machine oil is controlled using a rotation speed adjusting means for adjusting the rotation speed of the compressor and a controller for controlling the rotation speed adjusting means.

  In one aspect of the third aspect of the present invention, in the refrigerating and air-conditioning apparatus including the refrigerant circuit including the compressor, the condenser, the throttle element, and the evaporator, the condenser is the first condenser and the second condenser. And a liquid storage container between them, and the liquid storage container is present at or near a site where substantially all the refrigerating machine oil is dissolved in the refrigerant liquid condensed and generated in the condenser. A refrigerating and air-conditioning apparatus is provided. Here, “near” means that the refrigerating machine oil does not need to be located at the position where all of the refrigerating machine oil is substantially dissolved. Intended to be good.

  In another aspect of the third aspect, the present invention provides a method for operating a refrigeration air conditioner including a refrigerant circuit configured by a compressor, a condenser, a throttle element, and an evaporator, and the condenser is first condensed. And the second condenser is provided with a liquid storage container therebetween, and the stream supplied from the first condenser to the liquid storage container includes a refrigerating machine oil phase independent of the refrigerant liquid phase, The amount of condensation of the first condenser and the second condenser is adjusted so that substantially all of the refrigerator oil phase is dissolved in the refrigerant liquid in the storage container.

  In the refrigerating and air-conditioning apparatus and its operation method, it is particularly preferable to use a combination of a hydrofluorocarbon refrigerant and a refrigerating machine oil made of a synthetic oil such as mineral oil or hard alkylbenzene oil.

BEST MODE FOR CARRYING OUT THE INVENTION

  In the present invention, oil having limited solubility in the refrigerant liquid is used as the refrigerating machine oil. Since the refrigerating machine oil used in the conventional refrigerating and air-conditioning apparatus usually has such dissolution characteristics, the conventional refrigerating machine oil can also be used in the present invention. A particularly preferred combination is a refrigerating machine oil composed of a hydrofluorocarbon refrigerant and a synthetic oil such as mineral oil or hard alkylbenzene oil.

  In the present invention, the refrigerating and air-conditioning apparatus is a refrigerating machine used in a refrigerator, an air conditioner, etc., except for the features of the present invention related to the condenser described above and described in detail below. It may be used for a conventional refrigeration air conditioner.

  In the first aspect of the present invention, in the condenser, the liquid phase of the independent refrigerating machine oil (that is, the liquid phase different from the refrigerant liquid phase) always exists from the inlet to the outlet of the condenser. When an independent liquid phase of refrigerating machine oil exists in the condenser, sludge that cannot be completely dissolved in the refrigerant liquid can be dissolved in the existing refrigerating machine oil phase, and sludge precipitation is prevented. Furthermore, even if sludge is not completely dissolved in the refrigeration oil phase, the refrigeration oil phase tends to move along the inner wall of the pipe as described above. It will be coated, and the deposited sludge will hardly adhere to the inner wall of the pipe.

  In the second aspect of the present invention, the condenser has a temporarily independent refrigerator oil phase. In this case, similarly to the above, the refrigerator oil phase as an independent phase flows along the inner wall of the pipe, so that sludge adhering to the inner wall of the pipe can be dissolved and separated.

  In the third aspect of the present invention, in a liquid reservoir provided in the middle of the condenser, an amount of sludge substantially equal to at least the amount that cannot be dissolved in the refrigerant liquid is deposited. Will not precipitate. As a result, in the condenser downstream from the liquid reservoir, even if sludge deposited in the liquid reservoir may be dissolved in the refrigerant liquid, the precipitation of new sludge is substantially prevented.

The present invention will now be described in more detail with reference to the accompanying drawings.
Embodiment 1 FIG.
An embodiment of the first aspect of the present invention will be described with reference to FIG. Fig.1 (a) is a typical flow sheet of the refrigerant circuit of the refrigerating and air-conditioning apparatus of the present invention. The flow sheet of FIG. 1 (a) is substantially the same as FIG. 11 (a) (ie, 1 is a compressor, 2 is a condenser, 3 is a throttle element, 4 is an evaporator) and is substantially The same elements are denoted by the same reference numerals (the same applies to other flow sheets). Although the sludge separator is not shown in FIG. 1A, it may or may not be provided as necessary (the same applies to other aspects).

FIG. 1B shows a graph illustrating the behavior of the refrigerant liquid, the refrigerating machine oil, and the sludge in the condenser 2 of the mode shown in FIG. 1A. Since it is the same as the description with reference to FIG. 11B first, the description of the same contents is omitted. However, in this aspect, as is apparent from the graph, the flow rate condition of the refrigerating machine oil in the condenser is relative to the refrigerant liquid.
(Flow rate ratio 12 of refrigerating machine oil)> (saturation concentration 10 of refrigerating machine oil)
To be maintained.

  Next, the operation of the aspect shown in FIG. Regarding the flow of the refrigerant, the refrigerating machine oil, and the sludge, only the operation that occurs in the condenser 2 will be described, and the other parts are substantially the same as the description with reference to FIG. Is the same).

  At the condenser inlet (point A), the refrigerant gas discharged from the compressor and the refrigerating machine oil flow. Refrigerating machine oil contains suspended solid sludge and dissolved sludge. As described above, generally, refrigeration oil easily flows along the inner wall of the refrigerant pipe.

  In the condenser 2, as the refrigerant gas changes into the refrigerant liquid from the inlet (point A) to the outlet (point B), the amount of the refrigerant liquid in the condenser increases, and thus the ratio of the refrigerant liquid increases. . As a result, the flow rate ratios (curves 12 and 13) of the refrigerating machine oil and the sludge to the refrigerant liquid both decrease. At this time, both the refrigerating machine oil and the sludge are dissolved in the refrigerant liquid, but only the refrigerating machine oil and sludge (14 and 15) corresponding to the amount exceeding the saturation amount remain without being dissolved in the refrigerant liquid.

In this embodiment, (refrigerating machine oil flow rate ratio 12)> (refrigerating machine oil saturation concentration 10) with respect to the refrigerant liquid
Is maintained at the condenser outlet (point B),
(Flow rate ratio of refrigerating machine oil not dissolved in refrigerant liquid 14, 12-10)> 0
It becomes. Therefore, the state where the refrigerating machine oil phase is present as an independent liquid phase along the inner wall surface of the refrigerant pipe while being undissolved is maintained throughout the condenser.

As a result, at the condenser outlet (point B) (flow rate ratio 15 of sludge not dissolved in the coolant)> 0
Even if there is sludge that remains undissolved in the refrigerant liquid and can remain on the inner wall surface of the refrigerant pipe, the refrigerator oil phase remains undissolved in the refrigerant liquid on the inner wall surface, That is, since it flows as an independent liquid phase, the sludge does not adhere to the inner wall surface and flows into the throttle element 3 together with the refrigerating machine oil. Moreover, the sludge which can be melt | dissolved in refrigerating machine oil can melt | dissolve in the refrigerating machine oil phase in which at least one part exists as an independent liquid phase.

Thus, in this aspect, adhesion of sludge is prevented, and the amount of sludge that precipitates is reduced by dissolving the sludge in the independent refrigerator oil phase.
Therefore, as in the conventional example, all the refrigerating machine oil is dissolved in the refrigerant liquid, and the sludge dissolved in the oil is deposited on the inner wall surface of the refrigerant pipe to form a fine solid or high viscosity liquid precipitated sludge. It does not adhere to the solid sludge that is floating around it and grows into a large deposit.

  As described above, the solid sludge that does not adhere to the inner wall surface of the refrigerant pipe and the sludge that dissolves in the refrigerating machine oil are not limited to the sludge discharged from the compressor, but are reaction products resulting from the reaction with the refrigerant pipe material. In addition, it is considered that the waste and the waste behave as a solid sludge, and the remaining processed oil or the like behaves as a sludge that dissolves in the refrigerating machine oil.

  Therefore, as in the conventional example, sludge grows greatly on the inner wall surface of the refrigerant pipe in the condenser and the flow path resistance increases, and it is suppressed that the refrigerating capacity is reduced due to a decrease in the circulation amount of the refrigerant. The operation of a stable refrigeration air conditioner can be performed. Furthermore, even when a sludge separator composed of a filter with a fine wire mesh is provided between the condenser 2 and the throttle element 3, large sludge particles are separated from the inner wall of the pipe, thereby causing the filter to rapidly The occurrence of clogging is greatly reduced and long-term operational reliability can be ensured.

Embodiment 2. FIG.
An embodiment of the second aspect of the present invention will be described. FIG. 2 is a schematic flow sheet of the refrigerant circuit of the refrigerating and air-conditioning apparatus of the present invention. The flow sheet of FIG. 2 is substantially similar to FIG. 1 (a) (ie, 1 is a compressor, 2 is a condenser, 3 is a throttling element, 4 is an evaporator), and the same elements are the same. The code | symbol is attached | subjected. The difference is that it has a control means 22 that temporarily sets the flow rate ratio of the refrigerating machine oil flowing through the condenser 2 to the refrigerant liquid of the refrigerating machine oil to a saturation concentration or higher temporarily.

  Since the basic flow of the refrigerant is the same as that of the first embodiment, the description thereof is omitted. Here, the control operation of the control means 22 will be described with reference to FIG. 2 and FIG. 3 which is an operation flowchart thereof.

First, in step 31, an operation start command for the compressor 1 is issued, and operation is started under normal operating conditions of the refrigeration air conditioner. That is, the same operation as that of the conventional refrigeration air conditioner described with reference to FIG. In other words, in the condenser, (refrigerating machine oil flow rate ratio 12) <(refrigerating machine oil saturation concentration 10) with respect to the refrigerant liquid
Carry out an operation that causes a condition to occur. In this operation, as described above, the sludge dissolved in the refrigerating machine oil tends to precipitate and adhere to the inner wall of the pipe.

Next, after time ΔT1 from the start of the operation of the apparatus, in step 32, the control means 22 adds the refrigeration oil to the condenser to increase the flow rate ratio of the refrigeration oil to the refrigerant liquid. Here, the flow rate condition of the refrigerating machine oil in the condenser is (flow rate ratio 12 of refrigerating machine oil)> (saturation concentration 10 of refrigerating machine oil) with respect to the refrigerant liquid.
To be. In this case, since there is refrigerating machine oil that cannot be completely dissolved in the refrigerant liquid in the condenser, the frozen liquid exists in the condenser as an independent liquid phase and moves along the inner wall of the pipe. Therefore, in this operation, when sludge has already adhered to the inner wall of the pipe, the sludge tends to dissolve in the independent refrigerating machine oil phase or peel off.

  Thereafter, in step 33, the flow rate condition of the refrigerating machine oil is restored to the original after a time ΔT2 from the addition of the refrigerating machine oil. Accordingly, there is no independent liquid phase of the refrigerating machine oil in the condenser.

The aforementioned times ΔT1 and ΔT2 are preferably selected as follows:
Under normal operating conditions, as in the conventional example, sludge that dissolves in refrigeration oil is concentrated, and all refrigeration oil deposits on the inner wall surface of the refrigerant piping that dissolves in the refrigerant liquid and adheres to a fine solid or highly viscous liquid. Tend to. Excessive sludge deposition and adhesion / growth hinder the operation of the refrigeration air conditioner. Therefore, it is necessary to remove the sludge that has adhered / grown before the sludge grows greatly.

Therefore, by adding the refrigerating machine oil to the condenser, the flow rate condition of the refrigerating machine oil is temporarily set to the refrigerant liquid (the refrigerating machine oil flow rate ratio 12)> (the refrigerating machine oil saturation concentration 10).
If so, the precipitated sludge adhering to the inner wall of the condenser can be re-eluted into the refrigerating machine oil and easily separated. Therefore, the time ΔT1 is the time until the precipitated sludge grows to a certain size, and the time ΔT2 is the time until the sludge that has precipitated and grown can be re-eluted and separated into the refrigerator oil phase. That is, the sludge is allowed to adhere for a time ΔT1 to the extent that does not hinder the operation of the refrigerating and air-conditioning apparatus, and then, the sludge that has adhered over the time ΔT2 is removed.

  The amount of refrigerating machine oil added to the condenser by the control means 22 depends on the type and amount of generated sludge, the type and quantity of refrigerant present, the type and amount of refrigerating machine oil already present, and the like by those skilled in the art. You can choose. For example, the amount of refrigeration oil added can be determined by a tri-and-error method so that there is an independent refrigeration oil phase.

  In addition, it is preferable to collect | recover the refrigeration oil which increased temporarily after time (DELTA) T2 progress, and you may implement by the method generally used in a refrigerating air conditioner. For example, it can be recovered in a suitable container provided downstream of the compressor by a gas-liquid separator such as a demister, mist separator or the like. Further, the refrigerating machine oil collected by the gas-liquid separator and stored in the container can be added to the condenser via a valve by a command from the controller based on ΔT1 and ΔT2, and the refrigerating machine oil can be reused.

In step 34, the above operation is repeated until a compressor stop command is issued from the system. When the compressor stop command is issued, in step 35, the flow rate ratio of the refrigerating machine oil to the refrigerant liquid is increased, and the refrigerating machine oil flow rate condition is again set to the refrigerant liquid ((refrigerating machine oil flow rate ratio 12)> (refrigerating machine oil flow rate). Saturation concentration 10)
Then, the liquid phase of the independent refrigerating machine oil is made to exist again, and the sludge adhering to the inner wall of the condenser pipe is dissolved or removed in the same manner as described above. Then, in step 36, the compressor is stopped.

  In this way, sludge does not grow greatly on the inner wall surface of the refrigerant pipe of the condenser 2, so that the flow resistance is increased and the refrigeration capacity is not lowered due to a decrease in the refrigerant circulation amount, and is stable for a long time. You can drive. Further, since the flow rate ratio of the refrigerating machine oil only needs to be temporarily increased by an amount necessary to suppress the growth of sludge, an efficient operation can be performed. Furthermore, since the flow rate of the refrigerating machine oil is increased before the compressor is stopped to reliably remove the precipitated sludge, stable operation at the time of restart is ensured, and the operation reliability of the apparatus can be improved.

In this embodiment, the flow rate condition of the refrigerating machine oil in the condenser is set to (refrigerant oil flow rate ratio 12)> (refrigerating machine oil saturation concentration 10) with respect to the refrigerant liquid.
In order to peel off the attached sludge, the refrigeration oil that is substantially insoluble in the refrigerant or weakly soluble in the refrigerating machine oil is effective. As for machine oil, a large amount of refrigerating machine oil can be temporarily added to increase the flow rate ratio of the refrigerating machine oil to the refrigerant liquid so that sludge can be peeled off, and adhesion of sludge can be suppressed.

Embodiment 3 FIG.
Next, a third embodiment having more specific control means 22 will be described. FIG. 4 shows a flow sheet of the refrigeration air conditioner according to the third embodiment. In the figure, 41 is an oil reservoir (provided in advance with refrigerating machine oil) provided in the middle of the compressor 1 and the condenser 2, 42 is one at the bottom of the oil reservoir 41 and the other is the condenser 2. Is an oil injection pipe connected in the middle of the valve, 43 is a valve provided in the middle of the oil injection pipe, 44 is a controller that sends a control signal to open and close the valve 43, and these 41, 42, 43 and 44 are the above-mentioned The control means 22 is configured. The other parts are substantially the same as those in the second embodiment, and thus the description thereof is omitted. Note that the refrigerant from the compressor 1 to the condenser and the refrigerating machine oil (the existing refrigerating machine oil) are supplied directly to the inlet of the condenser 2 via the oil reservoir 41.

  Since the basic flow of the refrigerant is the same as that of the first embodiment, the control contents of the control means 22 will be mainly described here with reference to the flowchart of FIG. 5 showing the control operation of the refrigeration air conditioner.

First, in step 51, an operation start command for the compressor 1 is issued, and the operation of the refrigeration air conditioner is started in the same manner as in the second embodiment. In step 52, after the operation of the compressor 1 is started, after time ΔT 1, the valve 43 is opened, and the refrigerating machine oil previously placed in the oil reservoir 41 is injected into the condenser 2. Here, the injection amount of oil is (refrigerant oil flow rate 12)> (refrigerating machine oil saturation concentration 10) with respect to the refrigerant liquid.
To be. After opening the valve 43, in step 53, the valve 43 is closed after time ΔT2. Also in this embodiment, refrigeration oil is recovered downstream of the compressor and added to the condenser as described above. About time (DELTA) T1 and (DELTA) T2, since it is the same as that of Embodiment 2, description is abbreviate | omitted.

In step 54, the above operation is repeated until a compressor stop command is issued from the system. In step 55, the valve 43 is opened, and the flow rate condition of the refrigerating machine oil is again set in the condenser with respect to the refrigerant liquid (flow rate ratio 12 of refrigerating machine oil)> (saturation concentration 10 of refrigerating machine oil).
In step 56, the compressor is stopped.

In this way, the second embodiment described above can be specifically implemented, and the same effect can be achieved.
The same action and effect can be obtained even when the oil injection pipe 42 is connected to the condenser 2 at the inlet of the condenser 2. In particular, it is preferable to connect to a portion where sludge begins to precipitate in the condenser, and it is particularly preferable that the effect is particularly a portion corresponding to the point C or slightly upstream.

Embodiment 4 FIG.
Next, a fourth embodiment will be described. FIG. 6 is a schematic flow sheet of the refrigeration air conditioner according to the fourth embodiment, which is the same as that of the third embodiment except that the oil reservoir 41 is provided in the high-pressure space of the compressor 1. Therefore, since the operation of this apparatus and the operation due to this operation are substantially the same as those in the third embodiment, the description thereof is omitted. In the present embodiment, the same effect as in the third embodiment can be achieved, but in addition, the refrigeration and air-conditioning apparatus can be simplified by integrating the oil reservoir with the compressor.

Embodiment 5. FIG.
Next, a fifth embodiment will be described. FIG. 7A shows a schematic flow sheet of the refrigeration air conditioner according to the fifth embodiment. 61 is a rotation speed adjusting means for adjusting the rotation speed of the compressor 1, and 62 is a controller for sending a command signal to the rotation speed adjusting means so as to increase or decrease the rotation speed of the compressor 1. Further, the compressor 1 is driven by a rotating machine such as an electric motor and, as schematically shown in FIG. 7B, discharge of refrigeration oil per unit refrigerant flow rate at a rotational speed exceeding the normal rotational speed. It has oil discharge characteristics that increase in volume. Others are the same as those in the second embodiment, and thus description thereof is omitted. That is, in this aspect, the rotation speed adjusting means 61 and the controller 62 are provided as the means 22 for controlling the addition of the refrigerating machine oil.

  Next, since the basic flow of the refrigerant is the same as that in the first embodiment, the control contents of the control means 22 will be mainly described here with reference to the flowchart of FIG. 8 showing the control operation of the refrigeration air conditioner.

First, in step 71, an operation start command for the compressor 1 is issued. By this command, the operation of the refrigeration air conditioner is started in the same manner as in the second embodiment. In step 72, after the start of the operation of the compressor 1, after the time ΔT1, the rotation speed of the compressor 1 is increased. Since the compressor 1 has the oil discharge characteristic as described above, the discharge amount of the refrigerating machine oil per unit refrigerant flow rate increases. Here, the number of revolutions is such that the flow rate condition of the refrigerating machine oil in the condenser is (refrigerating oil flow rate 12)> (refrigerating machine oil saturation concentration 10) with respect to the refrigerant liquid.
Temporarily increase the amount of refrigeration oil so that

  When the rotation speed of the compressor 1 is increased and the time ΔT2 has elapsed, in step 73, the rotation speed of the compressor 1 is restored. Since the time ΔT1 and the time ΔT2 are the same as those in the second embodiment, the description thereof is omitted.

In step 74, the above operation is repeated until a compressor stop command is issued from the system. In step 75, the rotation speed of the compressor 1 is increased, and the flow rate condition of the refrigerating machine oil is again set to (refrigerant oil flow rate ratio 12)> (refrigerating machine oil saturation concentration 10) with respect to the refrigerant liquid in the condenser. In step 76, the compressor is stopped.

  As described above, the present embodiment can achieve the same effect as that of the third embodiment, but in addition, there is also an effect that the apparatus is simplified because the attached piping parts are unnecessary.

Embodiment 6 FIG.
Next, a sixth embodiment will be described. FIG. 9 shows a schematic flow sheet of the refrigerating and air-conditioning apparatus according to the sixth embodiment. In the figure, reference numeral 81 denotes a first condenser, 82 denotes a second condenser, and 83 denotes a liquid reservoir provided between the first condenser 81 and the second condenser 82.

Here, the ratio of the amount of heat exchange in the first condenser 81 and the second condenser 82 is such that the flow rate condition of the stream including the refrigerant liquid and the refrigerating machine oil flowing into the liquid reservoir 83 is the same as the refrigerant liquid in the condenser. (Flow rate ratio 12 of refrigerating machine oil)> (saturation concentration 10 of refrigerating machine oil)
It is set to become. That is, the amount of the refrigerant liquid to be condensed is controlled so that the existence of the liquid phase of the independent refrigerating machine oil is maintained. In other words, the amount of condensation of the refrigerant liquid as a whole is determined from the specifications of the refrigeration air conditioner, and the amount of condensation in the first condenser is determined from the relationship of the solubility between the refrigerant liquid and the refrigerating machine oil. The rest is condensed in a second condenser. Of course, the position of the liquid reservoir may be shifted instead of or in addition to the amount of condensation. Further, in the liquid reservoir 83, substantially all the refrigerating machine oil is dissolved in the refrigerant liquid.

  FIG. 10 is a schematic detailed view of the liquid storage container 83. In the figure, 91 is a liquid storage container, and 92 is an inflow in which one end is inserted into the refrigerant liquid stored in the liquid storage container 91. A pipe, 93 is a refrigerant gas outflow pipe through which refrigerant gas flows out, 94 is a refrigerant liquid outflow pipe through which refrigerant liquid flows out, 95 is refrigerant gas, 96 is refrigerant liquid, and 97 is refrigerating machine oil. As shown in the figure, from the first condenser 81, a stream containing the refrigerant liquid phase, the refrigerator oil phase, and the refrigerant gas flows into the liquid storage container 91. Since other elements of the apparatus are the same as those in the first embodiment, description thereof is omitted.

  Next, the operation will be described. Only the operations that occur in the first condenser 81, the second condenser 82, and the liquid reservoir 83 (or 91) will be described. The behavior of the refrigerant liquid, the refrigerating machine oil, and the sludge from the first condenser 81 to the second condenser 82 will be described with reference to FIG.

The flow rate condition of the refrigerating machine oil in the condenser is (refrigerating machine oil flow rate 12) <(refrigerating machine oil saturation concentration 10) with respect to the refrigerant liquid.
In this case, as the amount of refrigerant liquid condensed increases, the amount of refrigerating machine oil that exists as an independent phase decreases, and all the refrigerating machine oil dissolves in the refrigerant liquid at point C. In this case, the sludge dissolved in the refrigerating machine oil is deposited in an amount corresponding to 16, and originally remains on the inner wall surface of the refrigerant pipe and adheres thereto.

  However, in the case of this embodiment, since the liquid storage container 83 is provided at the point C, in the first condenser 81 in which an independent refrigerator oil phase exists, the precipitation of sludge is substantially suppressed, and the Sludge is deposited in the refrigerant liquid stored in the liquid storage container 83 located at the point C where the oil phase of the refrigerator does not exist. This amount of precipitation corresponds to 16, and is therefore substantially equal to the amount that can be deposited in the condenser, and no further sludge is substantially deposited in the condenser 82. Furthermore, since the sludge deposited in the refrigerant liquid in this way tends to become fine particles, the sludge hardly grows and adheres to the inner wall surface of the refrigerant pipe. As a result, new sludge does not deposit on the inner wall of the condenser pipe, and sludge that has already been generated is less likely to adhere.

  Further, even when the speed at which the refrigerant condenses and the flow rate of the refrigerant liquid increases relative to the speed at which the refrigerating machine oil dissolves in the refrigerant liquid, as shown in FIG. 10, for example, as shown in FIG. The stream containing the machine oil is caused to flow out from the inflow pipe 92 into the refrigerant liquid stored in the liquid storage container 91 to increase the contact area between the refrigerating machine oil and the refrigerant liquid and promote the dissolution of the refrigerating machine oil into the refrigerant liquid. Thus, since the refrigerating machine oil can be completely dissolved in the refrigerant liquid in the liquid reservoir 83, sludge can be deposited in the form of fine particles.

  In this way, the sludge grows greatly, the flow resistance increases, and the refrigerating capacity does not decrease due to the decrease in the circulation amount of the refrigerant, so that stable operation can be performed for a long time. Further, even when a sludge separator composed of a filter with a fine wire mesh is provided between the condenser 2 and the throttle element 3, the precipitated sludge is in the form of fine particles, so that the filter is not clogged. , Driving reliability can be ensured.

(The invention's effect)
This invention is characterized in that, in the first aspect, in the refrigeration air conditioner or the operation method thereof, the amount of refrigeration oil flowing in the condenser is larger than the amount of refrigeration oil that can be dissolved in the refrigerant liquid flowing in the condenser. There is. Due to such characteristics, the refrigeration oil phase is present without being dissolved in the refrigerant liquid, and sludge dissolved in the oil is deposited on the inner wall surface of the refrigerant pipe of the condenser. Precipitated sludge does not grow greatly by entraining solid sludge or the like due to the binder action. Moreover, sludge can be dissolved in the existing refrigerator oil phase. For this reason, there is no decrease in the refrigerating capacity due to an increase in flow path resistance and a decrease in the circulation amount of the refrigerant, and a stable operation can be performed over a long period of time.

  According to the second aspect of the present invention, in the second aspect, in the refrigeration air conditioner or the operation method thereof, the amount of the refrigeration oil flowing in the condenser is temporarily increased by the control means from the amount of the refrigeration oil that can be dissolved in the refrigerant liquid. Such a control means includes an oil sump container provided between the compressor and the condenser or in the high pressure space of the compressor, and then adds refrigeration oil to the condenser in a controlled manner. Alternatively, the compressor may be a compressor that is driven by a rotating machine and adds refrigeration oil to the condenser according to the number of rotations, and a unit that adjusts the number of rotations of the rotating machine and a controller thereof.

  With such a feature, the flow rate ratio of the refrigerating machine oil to the refrigerant liquid is temporarily made higher than the saturation concentration of the refrigerating machine oil refrigerant liquid, and the sludge is refrigerating machine oil before the sludge adhering to the inner wall of the condenser grows greatly. Since it is sufficient to temporarily increase the flow rate of the refrigerating machine oil by an amount necessary for suppressing the growth of sludge, efficient operation can be performed. In particular, when refrigerating machine oil is added according to the number of rotations of the oil reservoir or the rotating machine, the addition of the refrigerating machine oil is simple, and therefore the object of removing sludge can be easily achieved. As a result, the refrigerant circuit can be simplified, and downsizing and high reliability can be obtained.

  According to a third aspect of the present invention, in the refrigerating and air-conditioning apparatus or the operating apparatus thereof, the condenser includes a first condenser and a second condenser, and a liquid storage container is provided between them. The refrigerant liquid condensed and generated in the condenser is present at or near the site where the refrigerating machine oil is substantially completely dissolved, and as a result, the stream supplied from the first condenser to the liquid reservoir is an independent refrigerating machine oil. The amount of condensation of the first condenser and the second condenser is adjusted so that the refrigerator oil phase is dissolved in the refrigerant liquid in the liquid storage container. With such a feature, the refrigerating machine oil can be completely dissolved in the refrigerant liquid in the liquid storage container, so that sludge can be deposited in fine particles in the refrigerating machine oil, and on the inner wall surface of the refrigerant pipe. Sludge does not precipitate and grows large, and it does not cause clogging of the filter, and stable operation can be performed for a long time.

(A) It is a flow sheet of the refrigerating and air-conditioning apparatus according to Embodiment 1 of the present invention. (B) It is explanatory drawing of the behavior of the refrigerant | coolant liquid in a refrigerant | coolant piping, refrigerating machine oil, and sludge in the refrigerating air conditioning apparatus of Embodiment 1 of this invention. It is a flow sheet of the refrigerating air-conditioning apparatus of Embodiment 2 of this invention. It is a flowchart which shows the control action of the refrigerating system of Embodiment 2 of this invention. It is a flow sheet of the refrigerating air-conditioning apparatus of Embodiment 3 of this invention. It is a flowchart which shows the control action of the refrigerating system of Embodiment 3 of this invention. It is a flow sheet of the refrigerating and air-conditioning apparatus according to Embodiment 4 of the present invention. (A) It is a flow sheet of the refrigerating and air-conditioning apparatus according to Embodiment 5 of the present invention. (B) It is a related figure of the rotation speed of the compressor in Embodiment 5 of this invention, and the discharge amount of the refrigeration oil per unit flow rate. It is a flowchart which shows the control action of the refrigerating system of Embodiment 5 of this invention. It is a flow sheet of the refrigerating and air-conditioning apparatus according to Embodiment 6 of the present invention. It is a figure which shows typically the structure of the liquid reservoir container of Embodiment 6 of this invention. (A) It is a flow sheet of a conventional refrigeration air conditioner. (B) It is explanatory drawing of the behavior of the refrigerant | coolant liquid in a refrigerant | coolant piping, refrigerator oil, and sludge in the conventional refrigerating air conditioning apparatus.

Explanation of symbols

1 compressor, 2 condenser, 3 throttle element, 4 evaporator,
5 Sludge separator, 10 Saturated concentration of refrigerant oil in refrigerant oil,
11 Saturated concentration of sludge in the refrigerant liquid,
12 Flow rate ratio of refrigerant oil to refrigerant liquid,
13 Flow rate ratio of sludge to refrigerant liquid,
14 Flow rate ratio of refrigerant oil undissolved in refrigerant liquid to refrigerant liquid,
15 Flow rate ratio of the undissolved sludge in the refrigerant liquid to the refrigerant liquid,
16 Precipitation ratio of sludge to refrigerant liquid, 21 Refrigerant circuit,
22 control means, 41 oil reservoir, 42 oil injection pipe, 43 valve,
44 controller, 61 rotation speed adjusting means, 62 controller,
81 first condenser, 82 second condenser, 83 liquid reservoir, 91 container, 92 inflow pipe, 93 refrigerant gas outflow pipe, 94 refrigerant liquid outflow pipe,
95 Refrigerant gas, 96 Refrigerant liquid, 97 Refrigerating machine oil.

Claims (7)

  A refrigerating and air-conditioning apparatus comprising a refrigerant circuit constituted by a compressor, a condenser, a throttle element, and an evaporator, comprising control means for adding refrigerating machine oil to the inlet or in the middle of the condenser.   2. The refrigerating and air-conditioning apparatus according to claim 1, wherein the control means makes the amount of the refrigerating machine oil flowing through the condenser larger than the amount of the refrigerating machine oil that can be dissolved in the refrigerant liquid.   2. The refrigerating and air-conditioning apparatus according to claim 1, wherein the control means temporarily causes the amount of the refrigerating machine oil flowing in the condenser to be larger than the amount of the refrigerating machine oil that can be dissolved in the refrigerant liquid.   As control means, an oil reservoir container for storing refrigeration oil provided between the compressor and the condenser, an oil injection pipe for adding refrigeration oil contained in the oil reservoir container to the inlet or in the middle of the condenser, and in the middle of the injection pipe The refrigerating and air-conditioning apparatus according to any one of claims 1 to 3, further comprising a provided valve and a controller that instructs opening and closing of the valve.   The refrigeration preparation apparatus according to claim 4, wherein the oil reservoir is an oil reservoir that stores refrigeration oil in the high-pressure space of the compressor.   As a control means, a compressor driven by a rotating machine, and a compressor and compressor having an oil discharge characteristic in which the discharge amount of refrigerating machine oil per unit refrigerant flow rate increases when the rotating machine exceeds the normal rotational speed The refrigerating and air-conditioning apparatus according to any one of claims 1 to 3, further comprising: a rotation speed adjusting unit that adjusts the rotation speed of the motor and a controller that controls the rotation speed adjusting unit. In a refrigerating and air-conditioning apparatus having a refrigerant circuit composed of a compressor, a condenser, a throttle element, and an evaporator, the condenser is composed of a first condenser and a second condenser, and a liquid reservoir is provided therebetween. The refrigerating and air-conditioning apparatus is characterized in that the liquid storage container is present at or near a portion where the refrigerating machine oil is substantially completely dissolved in the refrigerant liquid generated by condensation in the condenser.

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