REGENERATING REFRIGERANT FLUIDS

DESCRIPTION Field of the invention

The present invention relates to a two-fluid apparatus for recovering and regenerating refrigerant fluids for refrigeration and/or air-conditioning systems, in particular but not exclusively, for car air conditioning systems.

Furthermore, the invention relates to a method for recovering and regenerating different refrigerant fluids operated by the above described apparatus.

Background of the invention

As well known, air conditioning systems for cars require frequent maintenance for testing the levels of the refrigerant fluids, or refrigerant, that is present into the system. The air conditioning system is commonly called A/C circuit.

Small amount of oil is added to the refrigerant for lubrication of the compressor of the circuit. Therefore, also the amount of oil, and not only the amount of refrigerant, has to be periodically controlled to ensure a correct operation of the air conditioning system.

Furthermore, during normal operation of the air conditioning systems, the refrigerant can be "contaminated" by air, by incondensable gas, by water and by solid particles, which are due to the wear and to the loss of tightness of the components of the circuit.

In particular, the maintenance of an air refrigeration and/or air- conditioning systems requires periodically emptying the circuit and recovering the refrigerant. Such maintenance provides, furthermore, a treatment to purify the circuit from the impurities and for restoring the optimal fluid levels.

To this purpose apparatus are known for recovering and regenerating refrigerants that comprise an evaporator consisting of a container that has an upper part with an inlet for a mixture refrigerant/impurities and a lower part where the impurities are gathered and where an outlet is present for their removal. Such apparatus can also comprise a compressor, a condenser and a reservoir for fresh refrigerant as well as a reservoir for regenerated refrigerant. The fluid contained in the reservoir is then put again into the system, for example into the system of a car.

Such apparatus are capable of treating a specific refrigerant that has determined features. In particular, the lubricant oil is specific for each type of used refrigerant.

With time, refrigerants have been developed with improved features, a reduced environmental impact, suitable to more effective disposal procedures. Even in this case, for each refrigerant a specific lubricant oil has to be used.

Recovering and regenerating machines are known arranged to treat at the same time different refrigerants, in order to treat, in a transition time of several years, air conditioning systems that use different refrigerants with a single machine. More precisely, it can occur that a workshop has to treat at the same time A/C circuits of new cars, which use a new refrigerant, and older cars, which use still an old refrigerant. To avoid that the workshop has to purchase two different machines, two-fluid machines have been developed that allow to treat two different refrigerants.

For example, recovering and regenerating machines were in the past developed capable of treating both refrigerant R12, and refrigerant R134a. The latter had much lower environmental impact than R12, and progressively substituted it. These two types of refrigerant were different from each other, but at the same time they were not incompatible. In other words, a small amount of R12 was tolerated. For example if R12 had been incorrectly put in air conditioning systems designed for R134a, since the two fluids had similar physical and thermodynamic characteristics, the A/C system could work correctly.

As well known, a refrigerant R1234yf has been recently developed, this refrigerant has an even lower environmental impact, and has started to replace progressively the very common refrigerant R134a.

However, R1234yf is inflammable, and then is completely incompatible with R134a. For this reason, an even small amounts of R1234yf cannot be tolerated in the earlier AC circuits. Furthermore, the new AC circuits in which R1234yf can work are completely different from the circuits that use R134a.

For this reason, circuit malfunctions can occur if even small amounts of R134a are added, even simply as impurities.

Therefore, the known apparatus for recovering and regenerating two different refrigerants are not adapted to treat refrigerant R1234yf in combination with refrigerant R134a, since even small contamination between the two refrigerants can cause a failure of the air conditioning system and of its mechanical components.

In fact, if a two-fluid apparatus of known type is used for treating in turn the two different refrigerants, a residue fraction of the refrigerant that has been treated first in the ducts of the recovering circuit, would remain in the valves, in the evaporator, in the mechanical components etc., when passing from a fluid to another, causing a contamination between the two fluids. Such contamination, in addition to cause a problem to the air conditioning system, can also pollute the refrigerant R1234yf that is contained in the collection reservoir. In this case, the refrigerant becomes unserviceable, causing a damage, since R1234yf has a very high cost.

On the other hand, a two-fluid machine that comprises two completely distinct circuits and components for the two fluids would have a cost comparable with the cost of two different machines, and would be not interesting for producers and customers.

Summary of the invention

It is a feature of the present invention to provide an apparatus for recovering and regenerating refrigerants for refrigeration and/or air conditioning systems, which allows carrying out selectively the recovering and the regenerating steps with refrigerants incompatible to each other. It is another feature of the present invention to provide an apparatus for recovering and regenerating refrigerants for refrigeration and/or air conditioning systems that can avoid the contamination between two different refrigerants during the recovering and regenerating operations in two different air conditioning systems.

It is a further feature of the present invention to provide an apparatus for recovering and regenerating refrigerants for refrigeration and/or air conditioning systems which is not much cumbersome and that has limited production costs.

In the following description

These and other objects are accomplished by an apparatus for recovering and regenerating a refrigerant in a refrigerating and/or air conditioning system, said apparatus comprising:

a first and a second recovery and regeneration circuits arranged to treat selectively a first, or a second, refrigerant recovered from said system, each of first and second recovery and regeneration circuits comprising:

a recovery duct and a delivery duct arranged to connect the recovery and regeneration circuit with said system, respectively arranged to recover a used refrigerant from the system and to deliver a regenerated refrigerant into the system;

a compressor arranged to compress the used refrigerant; an evaporator arranged to separate impurities from the used refrigerant coming from the system, in order to obtain a regenerated refrigerant;

a vacuum pump associated with the evaporator;

a condenser arranged downstream of the evaporator configured to condense the regenerated refrigerant;

a reservoir for collecting the regenerated refrigerant and the new refrigerant;

- a program means that is arranged to activate selectively the first and the second recovery and regeneration circuit responsive to the choice of a user between the first or the second refrigerant as used refrigerant to recover and regenerate;

wherein the first and the second recovery and regeneration circuit comprise, furthermore, valve means on the recovery duct and a pressure measuring means arranged upstream of the valve means;

wherein the program means is configured to operate said pressure measuring means for causing selectively said valve means to open and close, in such a way that when a user selects by the program means the first or the second refrigerant, the pressure measuring means measures a pressure in the first or in the second circuit that determines a correct or wrong choice of refrigerant by the user and said program means respectively opens or stops the valve means.

Advantageously, the first and the second recovery and regeneration circuit comprise in common the evaporator and a vacuum pump associated with the evaporator, in order to generate a two-fluid recovery and regeneration circuit.

In particular a vacuum pump is connected to the evaporator by a suction duct, the suction duct comprising a pressure transducer arranged to transmit an opening/closing signal to the valve means if the pressure transducer measures a pressure higher than a predetermined pressure in the evaporator.

In particular, if the recovery and regeneration cycle of the refrigerant has not been completed, for example owing to a blackout, the pressure transducer emits a signal of pressure higher than a predetermined value. Such value of higher pressure is caused by the fact that the compressor has not started or has not completed the suction step from the evaporator, for eliminating all the residues of refrigerant in the recovery and regeneration circuit. This way, it is avoided that a cycle can start if the recovery and regeneration cycle of the refrigerant has not been completed. So, it is avoided mixing two in two different used fluids of two distinct recovery and regeneration cycles in the two-fluid circuit. Advantageously, the program means is configured to allow for each of the two refrigerants the possibility of activating a function selected from the group consisting of:

recovering the refrigerant from the refrigerating and/or air conditioning system;

creating a vacuum in the refrigerating and/or air conditioning system; injecting a lubricating fluid;

injecting a tracing fluid;

delivering the regenerated refrigerant back into the system

According to another aspect of the invention, a method for recovering and regenerating a refrigerant in a refrigerating and/or air conditioning system comprises the steps of:

prearranging a first and a second recovery and regeneration circuits arranged to treat selectively a first or a second refrigerant recovered from said system;

wherein the first and second recovery and regeneration circuits comprise each:

a recovery duct and a delivery duct arranged to connect the recovery and regeneration circuit with said system, respectively arranged to recover a used refrigerant from the system and to deliver a regenerated refrigerant into the system;

a compressor arranged to compress the used refrigerant; an evaporator arranged to separate impurities from the used refrigerant coming from the system, in order to obtain a regenerated refrigerant,

a vacuum pump associated with the evaporator;

a condenser arranged downstream of the evaporator configured to condense the regenerated refrigerant;

a reservoir for collecting the regenerated refrigerant and the new refrigerant;

activating selectively the first and second recovery and regeneration circuit responsive to the choice of a user between the first or the second refrigerant as used refrigerant, to recover and regenerate;

wherein the method provides prearranging valve means on the recovery duct and the pressure measurement upstream of the valve means,

wherein the pressure measurement is operated for causing selectively the opening and the closing the valve means in such a way that, when a user selects the first or the second refrigerant, the pressure is measured in the first or in the second circuit for signalling the correct or wrong choice of refrigerant by the user and said program means respectively opens or stops the valve means.

Advantageously, a control step is provided associated with a vacuum pump and the evaporator, the control step comprises a pressure measurement step and a step of sending an opening/closing signal to the valve means, if the pressure measurement measures a pressure higher than a predetermined pressure in the evaporator.

Brief description of the drawings

Further characteristic and the advantages of the present invention will be made clearer with the following description of an exemplary embodiment thereof, exemplifying but not limitative, with reference to the attached drawings, in which like reference characters designate the same or similar parts, throughout the figures of which:

Fig. 1 shows a diagrammatical view of a two-fluid apparatus, according to the invention, for recovering and regenerating different refrigerants to each other, applied to an air conditioning system, for example of a car;

Fig. 2 shows a diagrammatical view of the two-fluid apparatus of Fig. 1 for recovering and regenerating different refrigerants;

Fig. 3 shows a block diagram that depicts the logical flow followed by the program means for activating and choosing the refrigerant;

- Fig. 4 shows a diagrammatical view of a recovery and regeneration cycle of the first refrigerant carried out with the two-fluid apparatus, according to the invention;

Fig. 5 diagrammatically shows a recovery and regeneration cycle the second refrigerant. Description of a preferred exemplary embodiment

With reference to Fig. 1 , an apparatus 100 is shown for recovering and regenerating a refrigerant in the refrigeration circuit of a refrigerating and/or air conditioning system 200. The apparatus 100 comprises a first and a second recovery and regeneration circuits 10, 20 arranged to treat selectively a first and a second refrigerant. In particular, the two refrigerants can be R134a and R1234yf. As also shown in Figs. 4 and 5, the two fluids can be used in respective circuits of conditioning.

In particular, the first and second recovery and regeneration circuits 10, 20 comprise each a recovery duct or low pressure duct (BP) 1 1 , 21 and a delivery duct or high pressure duct (AP) 12, 22. The low and high pressure ducts are adapted to connect the recovery and regeneration circuit with the air conditioning system 200. The ducts 1 1/21 and 12/22 are adapted to connect with the respective ducts 51 and 52 for respectively recovering a used refrigerant from the system 200 and for delivering the regenerated refrigerant into the system 200.

Structurally, as shown in Fig. 2, the first and second recovery and regeneration circuits 10, 20 comprise a compressor 13, 23 arranged to compress the used refrigerant. The two circuits comprise also an evaporator and separator 31 of impurities of the used refrigerant coming from the system 200, to obtain a regenerated refrigerant. Furthermore, the first and second recovery and regeneration circuits 10, 20 comprise a vacuum pump 41 associated with the evaporator 31 , and a condenser 14, 24 arranged downstream of the evaporator and separator 31 of impurities configured to condense the regenerated refrigerant. Furthermore, a reservoir 18, 28 is provided for collection of the regenerated refrigerant and of the new refrigerant.

As shown in Fig. 1 , in a preferred exemplary embodiment, the first and second recovery and regeneration circuits 10, 20 can comprise in common the evaporator 31 and a vacuum pump 41 associated with the evaporator 31. This way, it is possible to obtain a two-fluid recovery and regeneration circuit much more compact and easier to use.

Furthermore, as diagrammatically shown, for instance, in Fig. 2, the apparatus 100 comprises a program means 150 for activating selectively the first recovery and regeneration circuit 10 and the second recovery and regeneration circuit 20 according to the connection with the chosen recovery duct 1 1/21 and delivery duct 12/22, and responsive to the refrigerant adopted into the system to submit to maintenance. In particular, the program means 150 is configured to allow, for each of the two refrigerants, to activate a function selected from the group consisting of: recovering the refrigerant from the circuit, generating a vacuum in the circuit, injecting oil, injecting a tracing fluid and filling the air conditioning system with the regenerated refrigerant.

Furthermore, the first recovery and regeneration circuit 10 and the second recovery and regeneration circuit 20 can comprise each a valve means

15, 25 mounted to the recovery duct 1 1/21 , and a pressure measuring means 16 , 26 arranged upstream of the valve means 15, 25. More in detail, as shown in Fig. 1 , the valve means 15, 25 mounted to a respective branch 17, 27 that allows the movement of the refrigerant from the air conditioning system 200 (Fig. 1 ) to the recovery and regeneration circuit.

More in particular, the pressure measuring means 16, 26 is associated with the program means 150, as shown in Fig. 3, and is provided for opening and closing the valve means 15, 25. This way, when a user selects by the program means 150 the chosen fluid (Fig. 2), the pressure measuring means

16, 26 can measure a pressure in the corresponding first circuit 10 or second circuit 20, which determines the correct or wrong choice of refrigerant by the user. In other words, the user, after having connected the recovery duct 1 1/21 and the delivery duct 12/22 to the air conditioning system, selects the refrigerant through the program means 150, and then activates the corresponding recovery and regeneration circuit. If the user makes a wrong selection of the used refrigerant in the system, the pressure switch 16, 26 and the corresponding valve 15/25 prevent the introduction of the fluid and block the recovery and regeneration cycle of the refrigerant . So, an error is avoided that would cause a contamination between the two fluids, and that would cause damages to the air conditioning system, in addition to a loss of the refrigerant contained in the relative collection reservoir 8/28.

In particular, a vacuum pump 41 is connected to evaporator 31 by a suction duct 42. To suction duct 42 a pressure transducer 43 is mounted configured to transmit an opening/closing signal to the valve means 15, 25 when the pressure transducer detects a pressure higher than a predetermined pressure in evaporator 31. In particular, if the recovery and regeneration cycle of the refrigerant has not been completed, for example owing to a blackout, the pressure transducer 43 emits a signal of pressure that reveals a pressure higher than a predetermined value. Such value of pressure can be due to the fact that one of the compressors 13 or 23 has not started or has not completed the suction step from the evaporator 31 , for eliminating all the residues of refrigerant in the recovery and regeneration circuit 10, 20. This way, it is avoided that a cycle can start if the recovery and regeneration cycle of the refrigerant has not been completed. So, it is avoided a mixing between the two fluids that are used in two different recovering and regenerating cycles in the two-fluid circuit. In other words, the pressure transducer 43 allows signalling that the recovery and regeneration cycle of the refrigerant has been discontinued or in any case has not been completed, and also signalling that, for this reason, it is not possible to start a cycle if the previous cycle has not been completed. This is a further control to avoid any possible mixing and contamination between the two refrigerants, in particular R134a and R1234yf.

Fig. 3 shows diagrammatically, in a block diagram, the main steps by which program means 150 operates to actuate and select the refrigerant.

Fig. 4 shows in more detail, the steps for recovering the first refrigerant by suction through low pressure duct 11. Through a selection on the program means 150, the user activates the control that checks the correct refrigerant selection. If the refrigerant selection is correct, the regeneration procedure is started. As well known, the procedure provides leading the refrigerant in the evaporator where the refrigerant is superheated. Then, the fluid is lead through the compressor 13 and then through a condenser 14. Finally, the fluid is collected in reservoir 18. From reservoir 18, the fluid is delivered back in the air conditioning system through delivery duct 12 after reintroducing also a predetermined amount of lubricating fluid.

At this point, a vacuum is created by a common vacuum pump 41.

With this vacuum step, a washing step of the devices is substantially made, in order to switch from a refrigerant to another avoiding that a contamination occurs.

the recovering and the regenerating the second refrigerant is carried out similarly, as shown in Fig. 5.

The foregoing description of specific exemplary embodiments will so fully reveal the invention according to the conceptual point of view, so that others, by applying current knowledge, will be able to modify and/or adapt in various applications the specific exemplary embodiments without further research and without parting from the invention, and, then it is meant that such adaptations and modifications will have to be considered as equivalent to the specific embodiments. The means and the materials to realise the different functions described herein could have a different nature without, for this reason, departing from the field of the invention. It is to be understood that the phraseology or terminology that is employed herein is for the purpose of description and not of limitation.