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Title:
FILTERING DEVICE
Document Type and Number:
WIPO Patent Application WO/2021/133151
Kind Code:
A1
Abstract:
A filtering device (100) for facilitating service and maintenance of an air conditioning system (170) or a refrigerating system by a flushing machine (160), comprising connecting pipes (108) having at least two ends (104, 106), adapted for delivering refrigerant from the air conditioning system (170) or the refrigerating system from either one of the ends (104, 106) to the other end; at least one filter unit (102) mounted to the connecting pipes (108), for removing impurities from the refrigerant which passes therethrough; and a plurality of one-way valves (112, 114, 116, 118) respectively assembled at predetermined positions along the connecting pipes (108) for controlling the irreversible flow of the refrigerant along the connecting pipes (108) and creating unidirectional flow of the refrigerant through the filter unit (102), irrespective of the flow is delivered from which end of the connecting pipes (108), such that the filtered and unfiltered refrigerant flow through separate circuits within the connecting pipes (108).

Inventors:
YAP KWEE HENG (MY)
Application Number:
PCT/MY2020/000023
Publication Date:
July 01, 2021
Filing Date:
December 21, 2020
Export Citation:
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Assignee:
SPEED CAR AUTO PARTS SDN BHD (MY)
International Classes:
F25B43/00; F25B41/20; F25B41/40; F25B45/00
Domestic Patent References:
WO2004069366A22004-08-19
Foreign References:
US4887435A1989-12-19
US5638689A1997-06-17
US20040035805A12004-02-26
EP3483527A12019-05-15
Attorney, Agent or Firm:
CHIA, Sew Yeng (MY)
Download PDF:
Claims:
CLAIMS

1. A filtering device ( 100) for facilitating service and maintenance of an air conditioning system (170) or a refrigerating system by a flushing machine (160), comprising: connecting pipes (108) having at least two ends (104, 106), adapted for delivering refrigerant from the air conditioning system (170) or the refrigerating system from either one of the ends (104, 106) to the other end; at least one filter unit (102) mounted to the connecting pipes (108), for removing impurities from the refrigerant which passes therethrough; and a plurality of one-way valves (112, 114, 116, 118) respectively assembled at predetermined positions along the connecting pipes (108) for controlling the irreversible flow of the refrigerant along the connecting pipes (108) and creating unidirectional flow of the refrigerant through the filter unit (102), irrespective of the flow is delivered from which end of the connecting pipes (108), such that the filtered and unfiltered refrigerant flow through separate circuits within the connecting pipes (108).

2. A filtering device (100) according to claim 1, wherein either one of the at least two ends (104, 106) is adapted to connect to the flushing machine (160) and the other is adapted to connect to the air conditioning system (170), in such a way that the refrigerant from the air conditioning system (170) enters the filtering device (100) to be filtered before entering or after exiting the flushing machine (160).

3. A filtering device (100) according to any one of the preceding claims further comprising a casing (110) enclosing the connecting pipes (108), the at least one filter unit (102) and the plurality of one-way valves (112, 114, 116, 118).

4. A filtering device (100) according to claim 3, wherein the casing (110) further comprises a window (122) which allows visual inspection of the filter unit (102).

5. A filtering device ( 100) according any one of the preceding claims further comprising a lighting means (128) mounted besides the filter unit (102).

6. A filtering device (100) according any one of the preceding claims further comprising a reflecting means (130) adjacent to the filter unit (102). 7. A filtering device (100) according any one of the preceding claims, wherein the filter unit (102) comprises a filter cartridge (120).

8. A filtering device (100) according to claim 7, wherein the filter cartridge (120) is replaceable.

9. A filtering device (100) according to any one of the preceding claims further comprising a plurality of fastening means (132, 134, 142, 144, 146, 148, 150, 152, 154, 156) for securing the filter unit (102) and the plurality of one-way valves (112, 114, 116, 118) to the connecting pipes (108).

10. A filtering device (100) according to any one of the preceding claims further comprising one or more additional filter units.

Description:
FILTERING DEVICE

FIELD OF INVENTION

The invention relates to a filtering device for a servicing machine of an air conditioning (AC) system or a refrigerating system. In more particular, the invention relates to a filtering device which is to be equipped to a flushing machine or an AC servicing machine for flushing and cleaning of the AC system, particularly the automotive AC system of a vehicle.

BACKGROUND OF THE INVENTION

The heating, ventilation and AC system in the industry or household, domestic or industrial refrigerating system or AC system of an automobile, is required to be regularly serviced so that the condition of the system can be well maintained. For instance, the service and maintenance of the automotive AC system is capable of keeping the interior of the vehicle effectively cool, as well as reducing the risk of failure of the AC system. In general, the AC system of a vehicle can be serviced by physical cleaning of the condenser, cooling coil and compressor, replacing of coil filter, leakage checking, oil flushing, refilling of cooling fluid or refrigerant, and others. Most of these AC system service and maintenance tasks can also be carried out by an AC servicing machine, which is generally known in the art as a flushing machine.

There are a number of flushing machines available in the industry, which are designed to be used for flushing, cleaning and servicing the AC or refrigerating system, including the automotive AC system. A flushing process is considered an essential part of the AC service and maintenance processes, as this process is applied to remove impurities from the cooling fluid or refrigerant of the AC system. Such impurities could be dirt, oils, contaminants or solid residues, including rubber and metal residues. Impurities left in the refrigerant or the internal components of the AC system may clog up or damage the AC system, particularly its compressor, condenser, valves and cooling coil. Acidic contaminants may even cause corrosion to the internal components of the system. Therefore, it would be necessary that the impurities be removed from the AC refrigerant before such refrigerant is recycled back to the AC system and causes further damage to the system.

After flushing or servicing process of the AC system, the condition of the system could be generally maintained or improved. For example, the AC system may work more effectively to produce cleaner and cooler air. Besides, the lifespan of the AC system and its internal components may also be prolonged. However, a considerable amount of such impurities removed from AC system may remain in the flushing machine, resulting from said AC flushing or servicing process. As the impurities may also cause clogs, corrosions or damage to the internal components of the flushing machine, such as the solenoid valves, compressor, and others, the flushing machine may soon encounter various technical issues after a few rounds of flushing, including shortening of the machine’s service life.

In the cases where the AC system servicing workers or mechanics are lack of experience, or when the flushing machines used are worn out or clogged, it would also be difficult for the mechanics to determine whether the service and maintenance processes of the AC system have been effectively carried out. In addition, as the filtered and unfiltered refrigerant pass through the same set of pipelines within most of the flushing machines, there are possibilities that the removed impurities flows back to the AC system after the AC flushing or servicing process. Some of the AC systems may demonstrate a performance level which is below expectations even after the AC flushing or servicing process.

There are a number of technologies disclosed in the art relating to filtering device for AC system. China patent publication no. 206138819 discloses a filter for use in filtering the air conditioner pipelines, wherein the filter is cylindrical in shape and containing a filter screening drum. This filter contains an automated back flushing system which may serve as a maintenance mechanism for the AC system. Although the filter is used for maintaining the AC system, there is no disclosure in this document on how this filter is connected or integrated with the AC system. This filter applies a filtering mechanism by applying a water purifier cartridge and a water tank. The document also does not provide any disclosure on whether the filter can be equipped to a flushing machine for servicing the AC system. Another patent publication no. US 5,117,641 discloses a refrigerant recovery apparatus, which is to be connected to an AC system for recovering refrigerant when the AC system requires maintenance. This apparatus contains a few pipelines for transferring the liquid refrigerant, and a filter dryer which filters the refrigerant at the return line. The filter dryer is internally located within the apparatus for removing moisture and impurities, while the liquid pump of the apparatus will pump the refrigerant back through the AC system to perform the flushing. It is however not disclosed in this document on how a flushing machine can be connected to this filter dryer or how the filter dryer could facilitate the work of the flushing machine to improve the AC flushing performance.

Similar to the apparatus disclosed in the above prior art document, some of the commercially available flushing machines in the industry may contain a filtering member which is located within the machines. Such internally located filtering member is not visible to the mechanics hence does not provide any performance-checking or maintenance advantage to the flushing machine. These filtering members also do not provide any additional or performanceenhancing mechanism before or after the AC flushing process. Therefore, it remains a technical challenge in the art in providing a filtering device or mechanism which could efficiently overcome the technical issues associated with the performance and maintenance of the flushing machine.

SUMMARY OF INVENTION

One of the objects of the invention is to provide a filtering device which is capable of facilitating the flushing or servicing works of a flushing machine, while preventing or reducing the blockage and damage of the internal components of the flushing machine, thus prolonging its service life.

The invention also aims to provide a filtering device which can maintain or enhance the performance of AC servicing process, so that noticeably cleaner refrigerant could be returned to the AC system after the AC servicing process. At least one of the proceeding objects is met, in whole or in part, by the invention, in which the one of the embodiments of the invention describes a filtering device (100) for facilitating service and maintenance of an AC system (170) or a refrigerating system by a flushing machine (160), comprising connecting pipes (108) having at least two ends (104, 106), adapted for delivering refrigerant from the AC system (170) or the refrigerating Systran from either one of the ends (104, 106) to the other end; at least one filter unit (102) mounted to the connecting pipes (108), for removing impurities from the refrigerant which passes therethrough; and a plurality of one-way valves (112, 114, 116, 118) respectively assembled at predetermined positions along the connecting pipes (108) for controlling the irreversible flow of the refrigerant along the connecting pipes (108) and creating unidirectional flow of the refrigerant through the filter unit (102), irrespective of the flow is delivered from which end of the connecting pipes (108), such that the filtered and unfiltered refrigerant flow through separate circuits within the connecting pipes (108).

According to one embodiment of the invention, either one of the at least two raids (104, 106) of the connecting pipes (108) is adapted to connect to the flushing machine (160) and the other is adapted to connect to the AC system (170), in such a way that the refrigerant from the AC system (170) enters the filtering device (100) to be filtered before entering or after exiting the flushing machine (160).

In another embodiment of the invention, the filtering device (100) further comprises a casing (110) enclosing the connecting pipes (108), the at least one filter unit (102) and the plurality of one-way valves (112, 114, 116, 118). Preferably, the casing (110) further comprises a window (122) which allows visual inspection of the filter unit (102).

In accordance with another embodiment of the invention, the filtering device (100) further comprises a lighting means (128) mounted besides the filter unit (102).

Still another embodiment of the invention discloses that filtering device (100) further comprises a reflecting means (130) adjacent to the filter unit (102). According to certain embodiments of the invention, the filter unit (102) comprises a filter cartridge (120). Preferably, the filter cartridge (120) is replaceable.

A further embodiment of the invention discloses that the filtering device (100) further comprises a plurality of fastening means (132, 134, 142, 144, 146, 148, 150, 152, 154, 156) for securing the filter unit (102) and the plurality of one-way valves (112, 114, 116, 118) to the connecting pipes (108).

Another further embodiment of the invention discloses that the filtering device (100) further comprises one or more additional filter units.

The filtering device (100) of the invention may serve as a protective shield to a flushing machine, as it is able to screen through the refrigerant from an AC system before it enters the flushing machine, hence preventing, or reducing the amount of, the impurities from entering the internal components of the flushing machine. Apart from performing the filtering task, the filtering device (100) of the invention can also be applied for running an initial check on the condition of the refrigerant within an AC system or a refrigerating system, before the service and maintenance processes are carried out, so that a flushing machine can be refrained from being used for flushing highly contaminated refrigerant which may cause major damage to the internal components of an AC system. The filtering device (100) could also facilitate a flushing machine in providing a more cost-efficient AC service and maintenance processes, such as providing an additional filtering mechanism to the refrigerant after the flushing process under certain modes of flushing machine It is also designed to be compatible with a wide range of flushing machines for the AC system service and maintenance.

The present preferred embodiments of the invention consist of novel features and a combination of parts hereinafter fully described and illustrated in the accompanying drawings and particularly pointed out in the appended claims; it being understood that various changes in the details may be effected by those skilled in the arts but without departing from the scope of the invention or sacrificing any of the advantages of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

For the purposes of facilitating an understanding of the invention, there is illustrated in the accompanying drawing the preferred embodiments from an inspection of which when considered in connection with the following description, the invention, its construction and operation and many of its advantages would be readily understood and appreciated.

Figure 1 is a schematic diagram of the filtering device (100) as described in one of the embodiments of the invention, showing the respective circuits of the flow of refrigerant through the filtering device (100), the flushing machine (160) and the AC system (170), during different phases of flushing and filtering process.

Figure 2 is a front view of the filtering device (100) without the front cover of the casing (110), as described in one of the embodiments of the invention.

Figure 3 is a back view of the filtering device (100) without the back cover of the casing (110), as described in one of the embodiments of the invention.

Figure 4 is an external view of the filtering device (100), showing the exterior design of the casing (110) as described in one of the embodiments of the invention.

Figure 5 is the side view of the filtering cartridge (120) as described in one of the embodiments of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, the invention shall be described according to the preferred embodiments of the invention and by referring to the accompanying description and drawings. However, it is to be understood that limiting the description to the preferred embodiments of the invention and to the drawings is merely to facilitate discussion of the invention and it is envisioned that those skilled in the art may devise various modifications without departing from the scope of the appended claim.

The invention discloses a filtering device (100) for facilitating service and maintenance of an AC system (170) or a refrigerating system by a flushing machine (160), comprising connecting pipes (108) having at least two ends (104, 106), adapted for delivering refrigerant from the AC system (170) or the refrigerating system from either one of the aids (104, 106) to the otha end; at least one filter unit (102) mounted to the connecting pipes (108), for removing impurities from the refrigerant which passes therethrough; and a plurality of one- way valves (112, 114, 116, 118) respectively assembled at predetermined positions along the connecting pipes (108) for controlling the irreversible flow of the refrigerant along the connecting pipes (108) and creating unidirectional flow of the refrigerant through the filter unit (102), irrespective of the flow is delivaed from which end of the connecting pipes (108), such that the filtered and unfiltaed refrigerant flow through separate circuits within the connecting pipes (108).

Illustrated in Figure 1 is a schematic diagram of the filtering device (100), which is coupled with a flushing machine (160) fa the service and maintenance of an AC systan (170), as described in one of the anbodiments of the invention. According to one of the embodiments, the filtering device (100) can also be adapted to be used with the flushing machine (160) for the service and maintenance of a refrigerating system, such as a domestic or an industrial refrigerating or freezing system. As example, the fihering device (100) is heran described along with a flushing machine (160) applied for the flushing process of an automotive AC system (170) in a vehicle.

A flushing fluid or refrigerant is applied in the flushing process for AC service and maintenance. In general, the refrigerant is a cooling fluid used in an AC or refrigerating system. It can be in the form of gas or compressed liquid. The refrigerant described herein can be any commercially available refrigerant, including tetrafluoroethane (R-134a, or commercially known as Freon-134a), dichlorodifluoromethane (R-12, or commercially known as Freon-12), chlorodifluoromethane (R-22), 2,3,3,3-tetrafluoropropene (HFO- 1234yf), or a combination that is commercially known as R-406a (which is made up of chlorodifluoromethane (R-22), isobutane (R-600a) and chlorodifluoroethane (R-142b)).

As shown in Figure 1, the filtering device (100) of the invention can comprise three main components, i.e. an assembly of connecting pipes (108), at least one filter unit (102) and a plurality of one-way valves (112, 114, 116, 118). In accordance with one embodiment of the invention, the connecting pipes (108) can contain at least two ends (104, 106), for example, a first end (104) and a second end (106). In another embodiment of the invention, the connecting pipes (108) may also have additional two ends, such as a third end and a fourth end. Either one of the two ends (104, 106) of the connecting pipes (108) can be adapted to connect to the AC system (170) or to the flushing machine (160). For instance, the first end (104) of the connecting pipes (108) can be adapted to connect to the AC system (170), whereas the second end (106) of the connecting pipes (108) can be adapted to connect to the flushing machine (160), as depicted in Figure 1. Accordingly, during certain mode of the flushing machine (160), the refrigerant, or the flushing fluid from the flushing machine (160), can be delivered from the AC system (170) to the filtering device (100) to be filtered before entering the flushing machine (160) and returning to the AC system (170). Contrarily, the refrigerant can be delivered from the AC system (170) to the filtering device (100) to be filtered after exiting the flushing machine (160) and then returning to the AC system (170), during another mode of the flushing machine (160).

As set forth in the foregoing description, either end of the connecting pipes (108) can be connected to the AC system (170), at its high-side or low-side fittings, in order to receive the refrigerant from the AC system (170) and deliver it to the filter unit (102). In other words, both the first and the second ends (104, 106) of the connecting pipes (108) can be adapted as inlet or outlet for the flow of refrigerant, respectively during different phases of the AC flushing process or different modes of the flushing machine (160). These different modes of the flushing are generally preset or configured within the flushing machine (160) aiming to flush and clean different internal components of the AC system (170).

One skilled in the art may appreciate that the connecting pipes (108) is preferably made of pressure-resistant materials of metals or non-metals. For example, the connecting pipes (108) can be made of copper, stainless steel, zinc, copper or polyvinyl chloride (PVC). It is also preferable that the connecting pipes (108) are made of rust-resistant materials.

Figure 1 also illustrates that the filtering device (100) comprises a casing (110) which encloses the filter unit (102), connecting pipes (108) and the one-way valves (112, 114, 116, 118). The casing (110) can be made of various metal or non-metal materials, including stainless steel, zinc, aluminium, wood, or polymeric materials such as polypropylene, polyvinyl chloride (PVC), acrylic, or the like. According to one embodiment of the invention, the casing (110) is made of coated metal. Preferably, the casing (110) is made of an opaque material. Nevertheless, one skilled in the art may appreciate that the casing (110) can also be made of transparent or translucent materials for a more aesthetic look or a clearer view of the filtering mechanism within the filtering device (100).

In accordance with one embodiment of the invention, the casing (110) can comprise at least two openings (124, 126) for receiving the at least two ends (104, 106) of the connecting pipes (108). In one embodiment, the casing (110) can comprise a first opening (124) and a second opening (126). In other embodiment, the casing can comprise an additional pair of openings, for example a third opening and a fourth opening, to adapt to the third end and the fourth end of the connecting pipes (108). According to one embodiment of the invention, the first and the second openings (124, 126) can be located opposite from one another, as shown inFigure l. The openings ( 124, 126) allow the ends (104, 106) ofthe connecting pipes (108) to connect to the flushing machine (160) and the AC system (170) via other external pipelines.

As described in the preceding description, the filtering device (100) may employ at least one filter unit (102). This filter unit (102) can be mounted to and engaged with the connecting pipes (108) between the at least two ends (104, 106), so as to remove any impurities from the refrigerant which passes therethrough from either end of the connecting pipers (108) to the other end. According to one embodiment of the invention, the filter unit (102) can be located in such a predetermined position on the connecting pipes, in relation to the plurality of one-way valves (112, 114, 116, 118), so that the refrigerant passes through the filter unit (102) in a single direction (unidirection), irrespective of the flow is delivered from which end of the connecting pipes (108). Such unidirectional flow of the refrigerant through the filter unit (102) is shown by an arrow ( ) in Figure 1.

In accordance with one embodiment of the invention, the unidirectional flow of the refrigerant within the filtering device (100), can be achieved by the unique assembly of the plurality of one-way valves (112, 114, 116, 118). One-way valves are also known as check valves. These valves (112, 114, 116, 118) contains two ports at both ends to allow the flow of fluid thaethrough from the higher pressure end to the Iowa pressure end. In a prefared embodiment of the invaition, the filtering device (100) comprises four units of one-way valves, i.e. the first one-way valve (112), the second one-way valve (112), the third one-way valve (112) and the fourth one-way valve (112). In certain embodiments, the filtaing device (100) can comprise five or more one-way valves.

As shown in Figure 1, the plurality of one-way valves (112, 114, 116, 118) of the invention are respectively assembled at predetermined positions along the connecting pipes (108) to create the unidirectional flow of the refrigerant. Particularly, these one-way valves (112, 114, 116, 118) are assembled in such a way to control the flow of refrigerant within the filtering device (100) during each cycle of filtering process, so that the refrigaant passes through the filter unit (102) in a single direction, irrespective of the refrigaant is flushed from which end of the connecting pipes (108). Meanwhile, the flow of the refrigerant along the connecting pipes (108) could also be kept irrevasible with the unique assembly of these one-way valves (112, 114, 116, 118). As a result, the filtaed and unfiltered refrigerant would not be mixed with one anotha when passing through the set of connecting pipes (108) as they pass through separate circuits from one anotha.

Figure 1 demonstrates the respective circuits of the flow of refrigaant through the filtering device (100) during different phases of flushing and filtering of the AC system. In accordance with one preferred anbodiment of the invention, the servicing process of the AC system includes a low-side flushing phase, aiming to flush and clean the condensa (172) and the compressor (174); followed by a high-side flushing phase, in which the cooling coil (176) can be flushed or cleaned. In certain embodiments of the invention, the servicing process of the AC system only includes a low-side flushing phase. One skilled in the art may appreciate that these different phases of flushing process are subject to the settings configured in the flushing machine (160). For example, a two-way flushing machine would be configured with both a low-side flushing mode to conduct the low-side flushing, and a high-side flushing mode to conduct the high-side flushing. In any case, the filtering device (100) of the invention could be applied in the same manner to facilitate the AC flushing process of different flushing machines during different flushing modes.

In an example of a low-side flushing phase, where some internal components of the AC system (170) such as the compressor (174) and the condenser (172) could be cleaned, the refrigerant can be flushed from the flushing machine (160) into the internal circuit of the AC system (170). The unfiltered refrigerant from the AC system (170), particularly from the compressor (174) and the condenser (172), can be delivered into the filtering device (100) via the first «id (104) of the connecting pipes (108). The flow of the refrigerant through the filter unit (102) and connecting pipes (108) within the filtering device (100) during this low- side flushing phase can be shown in Figure 1 in dotted arrow line ( Accordingly, the unfiltered refrigerant from the compressor (174) and the condenser (172) of the AC system (170) flows through the first one-way valve (112) and passes through the filter unit (102) to be filtered therethrough. The filtered refrigerant can then flow through the fourth one-way valve (118) and exits the filtering device (100) via the second end (106) of the connecting pipes (108) to enter the flushing machine (160) for flushing.

On the other hand, the flow of the refrigerant through the filter unit (102) and connecting pipes (108) during an exemplary high-side flushing phase is shown in Figure 1 in dashed arrow line ( __ ). During such high-side flushing phase, where some oth« internal components of the AC system such as the cooling coil (176) could be cleaned, the unfiltered refrigerant from the AC system (170) can be delivered to the flushing machine (160) for flushing and then enter the filtering device (100) via the second end (106) of the connecting pipes (108). Within the filtering device (100), the unfiltered refrigerant can flow through the second one-way valve (114) and passes through the filter unit (102) to be filtered therethrough. The filtered refrigerant can then flow through the third one-way valve (116) and exit the filtering device (100) via the first «id (104) to return to the AC system (170). Generally, the condenser (172) and the compressor (174) of the AC system (170) are considered the relatively dirtier and more contaminated components which may be greatly clogged by impurities. During the low-side flushing phase, the filtered refrigerant flows out from the filtering device (100) via a separate circuit from that of the unfiltered refrigerant from the AC system (170). Therefore, it could prevent or greatly reduce the impurities originating from the condenser (172) and compressor (174) from entering the flushing machine (160). During the high-side flushing phase, where the relatively less contaminated cooling coil (176) is to be flushed, the filtering device (100) can serve as an additional filtering mechanism to the flushed refrigerant from the flushing machine (160), thus ensuring cleaner refrigerant return to the AC system (170).

According to certain embodiments of the invention, an AC system servicing process may contain a few cycles of low-side flushing phase and high-side flushing phase, depending on the settings of the flushing machine (160). For example, the flushing machine (160) may be configured to conduct a low-side flushing phase and a high-side flushing phase, repeatedly for two to three cycles of 5 to 15 minutes each. As set forth the foregoing description, the flow of refrigerant through the filter unit (102) would be kept unidirectionally so that the filtered refrigerant would not undergo a back flow within the filter unit (102). In other words, the filtered refrigerant passed through the filter unit (102) could be guided by the one-way valves(112, 114, 116, 118) along the connecting pipes (108) to exit the filtering device (100) in an irreversible manner, irrespective of the different flushing modes performed by the flushing machine (170) or different directions of pressure from the internal circuit of the AC system (170).

According to one embodiment of the invention, the casing (110) of the filtering device (100) can be formed into various three-dimensional structures, including cuboidal, cubical, cylindrical, trapezoidal or prismatic structures. In certain embodiment, the casing (110) is formed into a substantially trapezoidal structure. The casing (100) can be made into a one- piece structure or assembable pieces, containing a front cover and a back cover. Figure 2 shows a front view of the filtering device (100) as described in one of the embodiments of the invention, without the front cover of the casing (110), demonstrating the assembly of the filter unit (102), the first and the second opening (124, 126), and the connecting pipes (108) within the filtering device (100).

According to the embodiment of the invention, the filter unit (102) can comprise a filter housing (140). As illustrated in Figure 2, the filter housing (140) is provided with a substantially cylindrical, cuboidal or tubular structure. The filter housing (140) can be made of rust-resistant and pressure-resistant materials, including metals or non-metals. For example, the filter housing (140) is made of aluminium, stainless steel or polymers such as polypropylene.

In yet another preferred embodiment of the invention, the filter unit (102) is deployed relatively at the front part of the casing (110). Accordingly, the assembly of connecting pipes (108) and the plurality of one-way valves (112, 114, 116, 118) are located relatively at the rear part of the casing (110) as shown in Figure 3. In certain embodiments, the filter unit (102) can be located side-by-side with the assembly of connecting pipes (108) and the oneway valves (112, 114, 116, 118) within the casing (110). Alternatively, the filter unit (102) can be located at the relatively upper part of the assembly of connecting pipes (108) and the one-way valves (112, 114, 116, 118).

A further embodiment of the invention discloses that the filtering device (100) comprises a plurality of fastening means (132, 134, 142, 144, 146, 148, 150, 152, 154, 156). As shown in Figure 3, the filter unit (102) can be secured to the connecting pipes (108) by the first set of fastening means (132, 134), while the plurality of one-way valves (112, 114, 116, 118) can be secured to the connecting pipes (108) by the second, third, fourth and fifth sets of fattening means (142, 144, 146, 148, 150, 152, 154, 156). The fastening means (132, 134) can be metal or non-metal nuts, such as coupling nuts, lock nuts, flange nuts or the like.

Figure 4 is an external view of the filtering device (100), showing the exterior design of the casing (110) as described in one of the embodiments of the invention. According to one embodiment of the invention, the casing (110) of the filtering device (100) can comprise a window (122) which allows visual inspection of the filter unit (102), particularly when the casing (100) is made of opaque materials. By having such inspection window (122), the filtering device (100) allows the filtering mechanism that takes place within the filter unit (102) to be inspected during the flushing and filtering processes. An AC service worker or mechanic carrying out the flushing or servicing process would be able to ascertain the performance of the flushing or servicing process, by assessing the clarity of the refrigerant which passes through the filter unit (102). Apart from that, the window (122) also allows the initial check on the condition of the refrigerant within the AC system or the refrigerating system before the service and maintenance processes are carried out, where the turbidity of the refrigerant that passes through the filter unit (102) can be assessed. This allows the AC service workers or mechanics to determine whether the AC system is still in its serviceable condition and able to maintain its performance level after the service and maintenance processes, or it is highly contaminated that flushing is not recommended.

In accordance with another embodiment of the invention, the filtering device (100) further comprises a lighting means (128) mounted besides the filter unit (102). The lighting means (128) can be a light-emitting diode (LED), a fluorescent or incandescent bulb. In still another embodiment of the invention, the filtering device (100) further comprises a reflecting means (130) adjacent to the filter unit (102). The reflecting means (130) is a glass mirror, acrylic mirror or plastic mirror. The reflecting means (130) can also be reflecting sticker. According to one embodiment of the invention, the lighting means (128) and the reflecting means (130), as shown in Figure 2, are adapted to assist the inspection of the condition within the filter unit (102) through the window (122), while providing a better aesthetic look to the filter unit (102). Also as shown in Figure 2, The lighting means (128) can be powered by a power supply (158), preferably a potable power supply such as battery.

The filtering device (100) can be provided with different exterior design or aesthetic look. For example, it can contain a brand label (136). It can also contain a user panel (138). The user panel (138) can comprise a switch for the lighting means (128), user instruction, or others.

Figure 5 depicts a filter cartridge (120) applied in the filter unit (102), in accordance with one embodiment of the invention. The filter cartridge (120) can be a porous material, preferably made of a mechanical media. For example, the filter cartridge (120) can be a wire mesh, polymeric netting, nylon cloths, or the like. In accordance with another embodiment of the invention, the filter cartridge (120) is replaceable.

Another further embodiment of the invention discloses that the filtering device (100) further comprises one or more additional filter units. In certain embodiments, the filtering device (100) further comprises an additional filter unit The additional filter unit can be adapted to facilitate additional flushing modes configured within the flushing machine (160). In a further embodiment of the invention, the filtering device ( 100) can comprise a pressure meter accommodated within the casing (110). The pressure meter can be located before the filter unit (102) and adapted to check the pressure of the refrigerant in the filtering device (100).

The filtering device (100) of the invention can be used with a wide range of flushing machine (160), including one-way flushing machine and two-way flushing machine (160), as described in the foregoing description. Asides from the service and maintenance of automotive AC system, the filtering device (100) can also be equipped to the flushing machine (160) for checking or cleaning different internal components of domestic or industrial refrigerating systems, including fridges and freezers.

Although the invention has been described and illustrated in detail, it is to be understood that the same is by the way of illustration and example, and is not to be taken by way of limitation. The scope of the present invention is to be limited only by the terms of the appended claims.