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Title:
KIT WITH SELF CLEANING CAPABILITY FOR RETURN AIR FILTERING IN HVAC SYSTEMS
Document Type and Number:
WIPO Patent Application WO/2021/205431
Kind Code:
A1
Abstract:
An air filtration kit for HVAC system, which is adapted for mounting as an add-on kit to the HVAC system, wherein the kit has the capability to self-clean the filter mounted therein and is used to filter the return air flow in the system and a method for filtering return air flow in an HVAC system implementing said kit.

Inventors:
TWITO ISRAEL (IL)
Application Number:
PCT/IL2021/050372
Publication Date:
October 14, 2021
Filing Date:
April 04, 2021
Export Citation:
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Assignee:
TWITO ISRAEL (IL)
International Classes:
F24F3/16; B01D47/06; F24F13/28
Attorney, Agent or Firm:
WEBB, Cynthia et al. (IL)
Download PDF:
Claims:
CLAIMS

1. An add-on air filtration kit for HVAC systems comprising - a filter having a surface configuration; and - a bracket assembly in which said filter is mounted and is adapted for mounting to the system; and - a propelled assembly that is adopted for mounting on tracks that are formed in said bracket assembly; and a collecting means that is mounted in said propelled assembly and adapted for coming into contact with said filter for collecting the contaminants that accumulated on said filter; and a propelling means for propelling said propelled assembly into linear movement on the tracks of the bracket assembly parallel to the filter surface, so that once the propelled assembly is propelled into motion as stated, the collecting means will collect contaminants from the filter surface.

2. An add-on air filtration kit for HVAC systems according to claim 1, which additional comprises - a vacuum assembly that is connected to said collecting means for vacuuming the contaminants collected from the filter surface.

3. An add-on air filtration kit for HVAC systems according to claim 1, which additional comprises - a piping means that connects between said vacuum assembly and said collecting means, and follows the movement of the propelled assembly in a way that enables removing the contaminants collected from the filter and conveying them through it.

4. An add-on air filtration kit for HVAC systems according to claim 1, which additionally comprises - a spray assembly for spraying disinfectant or fragrance towards said filter or close to it.

5. An add-on air filtration kit for HVAC systems according to claim 1, which additionally comprises - an adapting means that is adapted for mounting in said bracket assembly for routing the air flow towards said filter.

6. An HVAC system in which an add-on air filtration kit according to any of claims 1-5 has been mounted.

7. An HVAC system according to claim 6, wherein - the system is a mini-central HVAC system; and said bracket assembly of the add-on kit is formed from two frame components in a rectangular configuration that is inter-connected, and wherein the first frame is adapted for mounting to the indoor unit of said mini-central HVAC system.

8. A method for filtering return air flow in an HVAC system that is comprised of the steps of - mounting an add-on kit according to claim 1 to the system; and from time to time propelling by the propelling means the kit’s propelled assembly into linear movement motion parallel to the filter surface, while collecting the contaminants that have accumulated on the filter by the kit’s collecting means; and vacuuming the contaminants collected by a vacuum assembly that is connected to the kit’ s collecting means; and removing the contaminants that were collected from the filter surface and conveying them through a pipe means that connects between said vacuum assembly and the collecting means of the kit, and follows the movement of the kit’s propelled assembly.

9. The method for filtering return air flow in an HVAC system according to claim 8, wherein the method also comprises a step of - spraying disinfectant or fragrance towards said filter or close to it by means of a spray assembly that is mounted in the kit’s propelled assembly.

10. The method for filtering return air flow in an HVAC system according to claim 8, wherein the method also comprises a step of - routing the flow of air towards the filter by an adapting means that is mounted in the bracket assembly of the kit.

Description:
KIT WITH SELF CLEANING CAPABILITY FOR RETURN AIR FILTERING IN HVAC SYSTEMS

FIELD OF THE INVENTION

The invention that is the subject of the Patent Application is in the field of air treatment systems known as HVAC (Heating, Ventilation and Air Conditioning), and particularly in the field of return air filtering means for them that comprise a filter that requires periodical cleaning.

BACKGROUND OF THE INVENTION

Filters are mounted in HVAC systems and are used to clean the air flowing into the system as air that is recirculated from the air-conditioned spaces by means thereof for recooling or reheating, and returned to those spaces (air flow that is referred to as "return air"). In most cases, the filters are components that are manufactured as a mesh, fabric or sponge on which contaminants accumulate that are filtered and separated by them from the flow of return air that is forced to pass through them. The filter must be cleaned from time to time to prevent it from becoming gradually clogged, as this could impair system performance, wasteful energy consumption, overheating and shorten the life of the system (the system is needed to overcome the blockage of air flow due to clogging of the filter). The need to periodically clean the filter is of additional importance, since the filter naturally traps microbial contaminants that are present in the air flow passing through it, and once these contaminants accumulate, they can be harmful to the occupants of the spaces in which the HVAC system is used. This therefore calls for cleaning and even meticulously disinfecting the filter elements.

In existing HVAC systems, cleaning the filter is cumbersome, as the cleaning operation requires physical accessing a location that could be difficult to access, disassembling the filter from the system, transferring it to another location for cleaning, and re-mounting it after cleaning at a location, which as stated, could be difficult to access.

Reference is made to Fig. 1, which demonstrates the challenge of cleaning the filter in an HVAC system, while for the purpose of the example, an HVAC of the type known as mini-central HVAC 10 is depicted installed in apartment space 20, as illustrated.

A mini-central HVAC system is commonly installed in condominiums, and is comprised of outdoor unit (compressor, evaporator or "motor") 25 that is installed outside the apartment; indoor unit (evaporator) 30 that is connected to outdoor unit 25 and installed in concealed space 40; means, one or more, for routing the air flow from the indoor unit to a space, one or more, that one wishes to air-condition in the apartment (in the illustrated example - corrugated duct 50 that routes the air flow through decorative grille 60 to space 70); and a means, one or more, enabling the return and recirculation of air from the air-conditioned space to the indoor unit (return air flow). In the illustrated example - decorative grilles 75, 80 allow for the passage of air from space 70 to concealed space 40 in which indoor unit 30 is installed. Once the return air flows inside concealed space 40, this allows for it to flow to indoor unit 30 through filter 90, which is mounted at the rear of the indoor unit as an integral part thereof, and the air is re-cooled or reheated by the indoor unit and streamed into space 70 and so on and so forth.

Therefore, according to the illustrated example, meeting the challenge of cleaning filter 90 calls for climbing into concealed space 40 (which sometimes can be, as illustrated, in an elevated and difficult to access location); manually disassembling and removing the filter, taking the filter down for cleaning at a location that is at a distance from it (e.g. - the bathtub); and subsequently cleaning the filter, climbing back and manually remounting the filter to the indoor unit.

Moreover, as the filter is hard to access (as example 90 in the illustrated example), a/c technicians have developed a practice of dismantling and neutralizing ahead of time the filter from the indoor unit (30 in the illustrated example), which is originally mounted in the system and forms an integral part thereof. Instead (or even in addition to that integral filter, in a way that naturally overloads the system operation), they mount filters as add-on components in each of the decorative grilles (75, 80 in the illustrated example), which face the air-conditioned space. Although this makes it somewhat easier to overcome the challenge of cleaning the filter, this still requires periodically accessing those grilles, manually disassembling each of the grilles, removing the filter, cleaning it, putting it back in place, and reassembling the grille.

Moreover, this practice of disassembling the integral filter from the indoor unit and mounting add-on filters in the return air grilles instead could contradict strict standards for gas appliances and the need to minimize the risk that in case of a leak, the leaked gas will find its way from the concealed space in which the indoor unit is installed to the air-conditioned space (if the a/c technician does not ensure to install corrugated ducts or pipes for routing the return air flow only from the add-on filters that were added to the grilles to the indoor unit, and left a possibility that a gas leak from the indoor until will seep into the concealed unit and from there to the indoor unit without the filter that was disassembled and removed). Therefore, prior to the invention that is the subject of the Patent Application, there was a need to provide a solution to the challenge of filtering the return air in HVAC systems, while making it convenient to periodically clean the filter used for this purpose in a way that will prevent the possibility of a gas leak (should one occur) finding its way to the return air. Solely for example’s sake, the invention will also be described in referring to mini-central HVAC systems (similar to system 10 in reference to Fig. 1), but a person skilled in the art will understand that the invention is also applicable in other types of HVAC systems.

SUMMARY OF THE INVENTION

The invention, which is the subject of the Patent Application, addresses the challenge of filtering return air in the HVAC system, while making it convenient to periodically clean the filter to be used for this purpose, and thereby also prevent a scenario where a gas leak from the system (should one occur) will find its way into the return air flow.

In one aspect, the invention is embodied in an air filtration kit for HVAC systems, which is adapted for mounting as an add-on kit to the HVAC system, wherein the kit has the capability to self-clean the filter mounted therein and is used to filter the return air flow in the system.

In one embodiment, the kit comprises a filter having a surface configuration; a bracket assembly in which the filter is mounted and is adapted for mounting to the system; a propelled assembly that is adapted for mounting on tracks that are formed in the bracket assembly; collecting means mounted in the propelled assembly and adapted to come into contact with the filter surface for collecting contaminants that accumulate on the filter; and a propelling means for setting the propelled assembly in a linear movement on the tracks of the bracket assembly parallel to the filter surface, in a manner that once the propelled assembly is set into movement, the collecting means will collect the contaminants from the filter surface.

In a second embodiment, the kit will additionally comprise a vacuum assembly that is connected to the collecting means for vacuuming the contaminants collected from the filter surface.

In a third embodiment, the kit also comprises a piping means that connects the vacuum assembly to the collecting means, and follows the movement of the propelled assembly in a way that enables removing and conveying the contaminants collected from the filter through it.

In a fourth embodiment, the kit also comprises a means for routing the return air flow to the kit.

In another aspect, the invention may be embodied in an HVAC system in which a kit as described above is mounted.

In another and additional aspect, the invention may be embodied in a general method for filtering the return air in the HVAC system, thereby giving a self-cleaning capability to the filter used to filter the return air flow in the system. A method that comprises the steps of -

Mounting an add-on kit to the system, wherein the kit comprises a filter having a surface configuration; a bracket assembly in which the filter is mounted and is adapted for mounting to the system; a propelled assembly that is adapted for mounting on the tracks formed in the bracket assembly; a collecting means that is mounted in the propelled assembly and is adapted to come into contact with the filter surface for collecting the contaminants that have accumulated on the filter; and a propelling means for setting the propelled assembly in linear movement on the tracks of the bracket assembly; and

From time to time propelling the propelled assembly into linear movement parallel to the filter surface by the propelling means, while collecting the contaminants that have accumulated on the filter by the collecting means; and

Vacuuming the contaminants collected by a vacuum assembly that is connected to the collecting means; and

Removal of the contaminants that were collected from the filter surface and conveying them through a pipe means that connects between the vacuum assembly and the collecting means, and follows the movement of the propelled assembly.

It should be borne in mind that the embodiments described below may be combined with other configurations in different ways, which are at least consistent with one of the principles of the invention described below, and the terminology used here should not be construed as limiting in any way.

BRIEF DESCRIPTION OF THE ATTACHED FIGURES

Different aspects of at least one embodiment of the invention that is the subject of the Patent Application will be described below, with reference to the accompanying figures (while no scale should be attributed to them). The figures are presented for illustrative purposes only and for facilitating an understanding of the different aspects of the invention and the possible configurations for its actual embodiment. The figures are part of the description, but should not be construed as limiting the invention in any way. In the figures, an identical or similar element that is visually depicted in several figures could be tagged by uniform numbering. For clarity, not every element was tagged in each of the figures. In the following figures:

Fig. 1 is, as stated, an illustration of a mini-central HVAC system that is installed in a prior art installation in an apartment space.

Fig. 2 depicts a mini-central HVAC system installed in an apartment space, wherein an add-on air filtration kit according to the invention is mounted to the system.

Fig. 3 depicts an exploded view of the system components illustrated in Fig. 2.

Fig. 4 is an exploded zoom-in view of the main components of the kit according to the invention, which are illustrated in Figs. 2 and 3.

Figs. 5 and 6 depict from two different angles the propelled assembly of a kit according to the invention, the components of which are illustrated in Fig. 4.

Figs. 7a and 7b depict perspective views from two different angles of a kit according to the invention, whose elements are illustrated in Fig. 4, while they are mounted to an indoor unit of a mini-central HVAC system.

Fig. 8 is an a-a cross-sectional view that is marked in Fig. 7.

Figs. 9 and 10 depict the movement of the propelled assembly illustrated in Figs. 5 and 6 in a kit according to the invention, the elements of which are illustrated in Fig. 4.

Fig. 11 depicts the mounting of a spray assembly for cleaning and/or disinfecting, as part of a kit according to the invention whose components are illustrated in Fig. 4.

Fig. 12 is a b-b cross-sectional view that is marked in Fig. 11.

Fig. 13 depicts an alternative propulsion option (lead screw) for the propelled assembly in a kit according to the invention.

Fig. 14 depicts an additional propulsion option (cable propulsion) for the propelled assembly in a kit according to the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION

Various apparatuses and components will be described below solely for the sake of providing an example of an embodiment of the claimed invention. The configurations described below are solely for example’s sake, and relate, as stated, to mini-central HVAC systems (similar to system 10 that is described above in referring to Fig. 1), but a person skilled in the art will understand that the invention is applicable to other types of HVAC systems. The configurations do not limit the claimed invention, and the latter may also apply to different apparatuses than those described below, as an example only. The claimed invention does not have to include all aspects of the apparatuses, components and methods described below, and is not strictly limited to those that exist in all the configurations described below. For the sake of integrity, it should be noted that the set of claims on the invention may be revised by way of amendment and/or by filing a divisional application. The skilled person will also understand that, for the sake of clarity, the configurations are described without delving into a lengthy description of components, methods and processes that are already common knowledge in the field and for which no tagged reference was provided in the figures (some of which are also not illustrated).

Reference is made to Figs. 2 and 3. Fig. 2 depicts mini-central HVAC system 10 installed in apartment space 20, wherein the system additionally comprises an add-on kit 210 according to the invention. Fig. 3 depicts an exploded view of the system components, as illustrated in Fig.

2.

Given a description of the structure of kit 210 below, in referring there to accompanying figures and comparing Figs. 2 and 3 to above Fig. 1, which described (in the Background of the Invention chapter) the challenge of cleaning filter 90 in mini-central HVAC system 10 installed in apartment space 20, then -

A person skilled in the art will understand that kit 210 enables adding on as an add-on assembly in existing mini-central HVAC systems without having to make structural changes to them. At the most, kit 210 obviates the need for the passage of return air also through the filter, which usually forms an integral part of indoor unit 30, and therefore may be removed before mounting an add-on kit (according to the practice described in the Background of the Invention chapter and as illustrated in Fig. 3) or left in place (in a manner that given the existence of a filter also as part of kit 210 would place a load on the system). Moreover, a skilled person would also understand that kit 210 can be integrated in such systems, which are required to strictly route only the return air flow to the filter (as stated in the Background of the Invention chapter due to strict standards for gas appliances and the need to minimize the risk that a gas leak will find its way through the concealed space in which the indoor unit is installed and to the air-conditioned space). According to the illustrated example, kit 210 is adapted for mounting to it means that will enable strictly routing only the return air flow to it. The illustrated example depicts two corrugated pipes 212, 214, one end of each one is connected to the flow passage from them to kit 210, and the other end of each one is adapted for mounting by means of adapters 216, 218 to decorative grilles 75,80, in a manner which, as stated, ensures the flow of only the return air to kit 210.

A person skilled in the art would understand that this is only an example, and a kit according to the invention may be formed in a way that allows for mounting other means to it, which will also allow for routing only the return air flow to it (e.g. by ducts and not necessarily corrugated pipes as illustrated, or a combination of such means), as well as a different plurality of such means (and not necessarily two, as illustrated).

Referring to Fig. 4. The figure depicts a zoom-in exploded view of the components of kit 210. Kit 210 comprises filter 405, bracket assembly 410, propelled assembly (a sort of "cart") 420, propelling means 430, vacuum assembly 440, piping means 450, spray assembly 460, and adapter means 470.

Filter 405 is formed in a surface configuration which, according to the illustrated example, is rectangular and whose dimensions fit the return air outlet in the indoor unit 30 (not illustrated). Filter 405 may be made as a tightly-knit mesh that is reinforced by a circumferential frame and intermediate ribs made by plastic injection. Filter 405 is designed to filter the return air flow, while leaving the contaminants on its side that is facing the remaining of the kit.

Bracket assembly 410 is designed as a rectangular frame that creates "window" 411, which, according to the illustrated example, is rectangular and its dimensions and fit for mounting filter 405 therein. The assembly also comprises tracks 412 and 414 that span along its length. Bracket assembly 410 is adapted for mounting in indoor unit 30 (not illustrated) (e.g. by means of metal screws, rivets, etc.). A skilled person would understand that bracket assembly 410 can be made of metal (profile parts) and/or plastic. According to the illustrated example, bracket assembly 410 is formed from two window-like frames, ‘410 and “410, which are assembled to each other, wherein frame ‘410 is individually tailored in its dimensions to the specific dimensions of the indoor unit (30) to which it its meant to be connected, and to filter 405 that is mounted inside it and is tailored in its dimensions to those of that specific indoor unit. A skilled person would understand that by assembling the bracket assembly from two frames as stated, this enables maintaining a modular uniformity of the frame component (“410) in which the tracks spanning its length are formed, whereas the second frame component (‘410') and the filter (405) mounted inside it are tailored to fit the specific indoor unit.

Propelled assembly 420 is formed as a sort of “cart”, which is adapted for mounting on the tracks formed in bracket assembly 410 and in a manner that facilitates the linear movement of propelled assembly 420 along their length. In the illustrated example, this is achieved by cylinder arrays ‘422 and “422 mounted on both sides of propelled assembly 420. Once filter 405 is installed in bracket assembly 410, propelled assembly 420 is positioned facing the filter and moves linearly parallel to the filter surface.

Collecting means 424 is adapted for mounting in propelled assembly 420 and to move with it. In the illustrated example, collecting means 424 is formed as an array of brushes 425, similar to an array found in a vacuum cleaner, and the collecting means are connected to container 426. Once propelled assembly 420 is set into movement, array of brushes 425 comes into contact with the surface of filter 405 and collects the contaminants that have accumulated on the filter and sweeps them to container 426.

Propelling means 430 is used to propel propelled assembly 420 into a linear movement on the tracks of bracket assembly 410. In the illustrated example, propelling means 430 is a friction propulsion apparatus comprising an electric motor and wheel propelled by it, which are mounted on propelled assembly 420, wherein the propelling wheel is adapted for coming into friction contact with bracket assembly 410, in a manner that facilitates the propulsion of propelled assembly 420 in a linear movement, as stated, along the length of the bracket assembly, in a manner that once the propelled assembly is set into movement from time to time, as stated, collecting means 424 collects the contaminants from filter 405.

Vacuum assembly 440 is used to vacuum contaminants that have accumulated on filter 405 and swept into container 426. In the illustrated example, vacuum assembly 440 is an electric vacuum cleaner unit that is adapted for mounting on bracket assembly 410 and comprises emptiable collection container 442, to which the contaminants are conveyed.

Piping means 450 connects between vacuum assembly 440 and collecting means 424 and follows the movement of propelled assembly 420 in a manner that facilitates removing the contaminants that were collected from filter 405 and conveying them through it to collection container 442. In the illustrated example, piping means 450 is a corrugated pipe whose one end is adapted for mounting to vacuum assembly 440 and its other end is adapted for mounting to collecting means 424.

Spray assembly 460 is used for spraying a disinfectant and/or fragrance towards filter 405 and/or close to it in a way that gives kit 210 additional capabilities of disinfecting (e.g. against microbial contaminants) and/or perfuming the return air that is streamed towards indoor unit 30. In the illustrated example, spray assembly 460 comprises disinfectant and/or fragrance container 462, pump 464 and multi-nozzle spray pipe 466. Once spray assembly 460 is mounted in kit 210, pipe 466 spans parallel to filter 405 and at a distance from it.

Adapting means 470 is formed as a sort of manifold and is adapted in its dimensions to be mounted facing bracket assembly 410. Adapting means 470 is adapted for mounting to bracket assembly 410 (e.g. by screws, rivets, bonding means, etc.). According to the illustrated example, adapting means 470 comprises two interfaces 472, 474, which are adapted in their dimensions to mount corrugated pipes 212, 213 (not illustrated) on them, so as to enable routing the return air flow to filter 405. A skilled person would understand that bracket assembly 470 may be made of metal and/or plastic parts.

Reference is made to Figs. 5 and 6. Figs. 5 and 6 depict from two different angles the propelled assembly (the “cart) 420 of kit 210.

According to the illustrated example, propelled assembly 420 is formed as in an I-shaped cross- sectional configuration (e.g. made form metal or plastic parts). Cylinder arrays ‘422 and “422 each comprise four cylinders. Collecting means 424 comprises two brushes 510, 512, which are positioned side by side and allow for sweeping the contaminants that have accumulated on the filter to a cavity (inner space) of container 426. The cavity of container 426 is connected to connector 516. Connector 516 is adapted for mounting piping means 450 (not illustrated). Propelling means 430 is mounted on propelled assembly 420, wherein, according to the illustrated example, the propelling means comprise electric motor 518 and wheel 619 that is propelled by it.

According to the illustrated example, in kit 210, removing the contaminants from the surface of filter 405 and gathering them to container 426 employs a sweeping method by means of an array of static brushes moving on the filter surface. However, a skilled person would understand that this may be achieved by various other methods, e.g. by propelling one brush or more that is mounted on the propelled assembly to actively scrub the filter surface (e.g. in a rotary motion), and then sweep the contaminants that have been removed by other brushes that will also be mounted on the propelled assembly.

Reference is made to Figs. 7a, 7b and 8. Figs. 7a and 7b depict perspective views from two different angles of kit 210 when mounted to indoor unit 30 of a mini-central HVAC system. Fig. 8 is an a-a cross-sectional view that is marked in Fig. 7.

According to the illustrated example, vacuum assembly 440 and its collection container 442 as well as disinfectant and/or fragrance container 462 and pump 464 of spray assembly 460 are mounted directly onto bracket assembly 410. The mounting configuration calls for periodically accessing kit 210 for emptying the vacuum assembly collection container (when filled with contaminants) or filling the spray assembly container (when empty), but the frequency of these maintenance operations is relatively low, and any skilled person will understand that they can be separated from the rest of the kit components and mounted in another more accessible location.

Moreover, a skilled person will understand that a kit according to the invention can be made to interface with an external household vacuum cleaner as a substitute for the dedicated vacuum assembly (so that a kit according to the invention will not include a vacuum assembly).

Also, according to the illustrated example, frame ‘410 of bracket assembly 410 is formed with shoulder 810, which supports filter 405 once kit 210 is mounted to indoor unit 30 and positions the filter so that its surface facing the kit will come into contact with brushes array 425 of collecting means 424. A skilled person will understand that once the integral filter originally assembled in indoor unit 30 is dismantled and filter 405 of the kit is mounted in its stead, as in the illustrated example, then there may be air gap between filter 405 and indoor unit 30 (see 850 - dimension L), which also facilitates and optimizes the filtering operation.

Frame “410 in bracket assembly 410 is additionally formed with profile 820 having a U-shaped configuration, which serves as a duct for routing the movement of piping means 450 inside it (according to the movement of propelled assembly 420).

Frame “410 in bracket assembly 410 is formed with tracks 412 and 414, each as a profile having a U-shaped configuration with protruding edges 830, 840, so that cylinder arrays ‘422 'and “422 'are adapted for movement inside the profile on them. A skilled person will also understand that a side rib of the U-profile which, as stated, serves as track 414, also serves as a track on which wheel 619 of propelling means 430 is operated (not illustrated in cross-section). A skilled person will understand that the specific design of bracket assembly 410, as described above in referring to the accompanying figures, is only an example, and the bracket assembly can be formed with other and different components for positioning the filter, mounting it to an indoor unit, routing the piping means, tracking the arrays of cylinders of the propelled assembly, and creating continuous contact with friction propulsion means, as needed to propel the propelled assembly.

Reference is made to Figs. 9 and 10. Figs. 9 and 10 depict the mode of movement of propelled assembly 420 in kit 210 (for the sake of convenience, the figures do not depict all the kt components).

In the illustrated example, piping means 450 is a corrugated pipe that lengthens/contracts linearly depending on the location of propelled assembly 420, wherein it is at all times inside profile 820, but a skilled person would understand that piping means 450 could be formed as a hanging pipe that follows the location of propelled assembly 420 in another manner (e.g. in the form of a pipe that is formed as a sequence of loops that are spaced apart or converge with each other depending on the location of the propelled assembly).

Moreover, propelled assembly 420 in kit 210 moves linearly along and parallel to the width dimension of indoor unit 30 (not illustrated) (from right to left and back again repeatedly, see Figs. 9 and 10), but a skilled person would understand that a kit according to the invention could be formed so that the propelled assembly will move along and parallel to the height dimension of the indoor unit (from top to bottom and back again repeatedly).

Referring to Figs. 11 and 12. Fig. 11 depicts the mounting of spray assembly 460 for cleaning and/or disinfection as part of kit 210, and Fig. 12 depicts a b-b- cross-sectional view that is marked in Fig.11 (while for the sake of convenience, the figures do not depict all the kit components).

According to the illustrated example, disinfectant and/or fragrance container 462 and pump 464 are mounted on bracket assembly 410 (on frame “410 of the assembly in the illustrated example), wherein an end of multi-nozzle spray pipe 466 is fixed to spacer component 1110, so that the disinfectant and/or fragrance (see in segmented lines) is sprayed in the direction of the return air in the kit. A skilled person will understand that this is only an example, and as mentioned, the container and pump components can be placed at another and more accessible location (while conveying the fluid from there by pipe to the multi-nozzle spray pipe) or the spray can be directed towards the filter of the kit. Moreover, a skilled person will also understand that a kit according to the invention may not initially have the capability of spraying the disinfectant and/or fragrance (so that a kit according to the invention will not comprise a spray component and will only provide the capability of from time to time cleaning the filter mounted therein).

Kit 210 is described above in referring to the accompanying figures, while propelling means 430, which serves to propel propulsion assembly 420, is a friction propulsion apparatus. However, a skilled person would understand that the invention can also be embodied in using other and different propelling means. Thus, for example -

Reference is made to Figs. 13 and 14. Fig. 13 depicts an alternative propulsion option - lead screw 1310 is propelled to rotate by electric motor 1312, and gives a linear movement to nut component 1314 that is fixed to propelled assembly 1320. Fig. 14 depicts another propulsion option - cable 1410 is propelled to move between two pulleys 1412, 1414 by means of electric motor 1416, with the cable fixed to propelled assembly 1420.

A skilled person would understand that a kit according to the invention also comprises a power supply means (e.g. electrical wiring for the propelling means, pump assembly and spray assembly); control and command means (e.g. - switch on and off components by wired command or remote control (wireless) of the propelling means, pump assembly and spray assembly); and hardware connector means (e.g. screws, rivets, clamps and other such standard means that are used to assemble the assemblies and means, their components and to connect them to each other). These are means and components familiar and known to persons skilled in the field.

We will emphasize again that the embodiments (configurations) of the invention described above, in referring to the accompanying figures, depict for the sake of example only the application of the inventive solution to the challenge of cleaning the filter in HVAC systems, in referring to a specific mini-central HVAC system, but a person skilled in the art would understand that the invention is applicable to other types of HVAC systems as well.

A skilled person would also understand that the mode of operation of kit 210, as described above in referring to the accompanying figures, also embodies a general method for filtering the return air flow in an HVAC system, which is comprised of the steps of mounting an add-on kit to the HVAC system, wherein the kit comprising a filter in a surface configuration (405), a bracket assembly (410) in which the filter is mounted and that is adapted for mounting to the system, a propelled assembly (420) that is adapted for mounting on the tracks formed in the bracket assembly (410), collecting means (424) that is mounted in the propelled assembly and adapted for coming into contact with the filter surface for collecting contaminants that have accumulated on said filter; a propelling means (430) for propelling the propelled assembly into linear movement on the tracks of the bracket assembly parallel to the filter surface, so that once the propelled assembly is propelled into motion as stated, the collecting means will collect contaminants from the filter surface; propelling from time to time the kit’s propelled assembly by the propelling means into a linear motion parallel to the filter surface of the kit, while collecting contaminants that have accumulated on the filter by the kit’s collecting means; vacuuming the contaminants that were collected by means of a vacuum assembly (440) that is connected to the kit’s collecting means; and removing the contaminants that were collected from the filter surface and conveying them through a piping means (450) that connects between the vacuum assembly and the collecting means of the kit, and follows the movement of the propelled assembly of the kit.

The method may also comprise an additional step of spraying a disinfectant or fragrance towards the filter or close to it by means of a spray assembly (460), which is mounted in the propelled assembly of the kit, and/or a step of routing the air flow towards the filter by an adapting means (470) that is mounted in the bracket assembly of the kit.

Therefore, in light of the description provided above in referring to the accompanying figures, a skilled person would appreciate the fact that a kit according to the invention provides a solution to the challenge of filtering the return air flow in HVAC systems, while making it convenient to periodically clean the filter used for this purpose and in a way that will prevent the possibility of a gas leak (should one occur) finding its way into the return air flow.

The Patent Applicant provided the above description in referring to the accompanying figures for illustrative purposes only. The description above should not be limited to the illustrated figures. On the contrary, the description provided should be seen as also covering a wide range of alternatives, adjustments and equivalents, all without deviating from the embodiments defined in the following set of claims.