Patent Application
20070125520
The present invention relates to an air conditioner cleaning apparatus and method effectively impeding odour and pollution originating from an air conditioning system. In particular, the present invention relates to a cleaning apparatus suitable for use in an air conditioning system in a vehicle.
An increasing number of vehicles are equipped with means for cooling the inlet air for the passenger compartment. The by far most common way of cooling the inlet air is by the use of an air conditioner, utilizing the refrigerating principles for cooling. In vehicles the air conditioner is typically assembled in connection with a fan and a heater radiator forming a heating/cooling system, or climate controller, for the interior of the vehicle. Schematically depicted in
The widespread use of air conditioners in vehicles have greatly improved the interior environment with regards to the temperature, but a well recognized drawback with the systems are that the cooled air may be perceived as not being fresh. Under certain conditions may even a characteristic and strong odour occur. In addition an increase of allergic reactions such as sneezing and teary eyes among drivers and passenger has been observed. Similar problems are well known in the area of ventilation of buildings and reports thereof may be found in for example the proceedings from the 5th International Conference on Indoor Air Quality and Climate, Vol III, pages 203-206, 1990.
The origin of the odour and the potentially harmful substances and micro organisms is to be found in the build-up and growth of for example mildew, mould, fungi and bacteria within the air conditioning unit. In particular, the evaporator provides an environment that allows micro organisms to get stuck to it and to grow. The for micro-organisms suitable environment arises since the cold evaporator will cause the humidity in the air to condensate on its surface. When the air conditioning unit is turned off, for example when the vehicle is not in use, the temperature will rise and the moist and the water remaining in especially corners and nooks of the cooling flanges will provide very suitable environments for the micro-organism to get stuck and grow. Micro-organisms are always present in the air, and since the fan will force a large volume of air through the evaporator and since the filtering device typically is relatively coarse, a continuous supply of micro-organisms to the air conditioner is to be expected. The fact that the evaporator is allowed to warm up is of importance since the growth of for example bacteria will be low at low temperatures. The modern type of automatic climate controllers (ACC), in for example cars, accentuate the problem, since these apparatus typically turns the air conditioner on and off frequently during normal operation.
In addition to the discomfort of odour and potential health risks the build-up of micro-organisms and other particles on the surface of the evaporator will impede the efficiency of the air cooling system. The lower efficiency will in turn lead to a higher fuel consumption and eventually to a noticeable loss of function in the ability to cool the ingoing air to a sufficient degree. The problem is of special importance for persons using vehicles in their profession, for example truck drivers, taxi drivers and operators of trucks, excavators etc.
One method, known in the art, of addressing the problem of odour and potentially harmful micro-organisms and particles comprises the use of air filters, provided after the cooling and heating units. Filtering devices are taught in U.S. Pat. No. 5,681,218 and references wherein. The systems utilizing filters have the drawback of, to be able to filter off small particles and odour, the filter must be of very high quality and with a high filtering factor. Such filter are expensive, needs to be replaced frequently and causes a substantial pressure drop, leading to a low air flow into the passengers compartment. In addition the filtering does not address the cause of the problem, the growth of micro-organisms in the air conditioning system, and will not prevent the efficiency degeneration of the evaporator.
Stationary air conditioning units, for example the types used in buildings, are often cleaned by spraying pressurized water on the evaporator. U.S. Pat. No. 5,509,972 teaches a method of cleaning by, in a controlled manner, spraying a foamy detergent on a heat exchanger. In a vehicle the evaporator of the air conditioner is typically not accessible without an extensive dismounting and these method are therefore not suitable for regular maintenance of a vehicle mounted air conditioning unit.
Commercially available products, for example Air Clean Control from Innotec USA, limits the growth of micro-organisms by the use of detergent in the form of mist or foam that is sprayed into the heating/cooling system of a vehicle, via the air inlet dampers in the passenger compartment. These methods have shown a short time effect in reducing odour, but are cumbersome to use and does not remove the build-up on e.g. the evaporator. In addition, it might, depending on the design of the heating/cooling system, not be possible to reach the interior of the air conditioning unit.
The objective problem is to provide a method and an apparatus for reducing the discomfort of odour and potential health risks associated with the existence and growth of micro-organisms such as bacteria, fungi, mould and mildew in the air conditioning units of vehicles.
The problem is solved by the system as defined in claim 1 and the method as defined in claim 12.
In order to achieve the above-mentioned object, according to the invention, a cleaning system comprising a cleaning assembly for cleaning cooling and/or heating units of air conditioners in vehicles is provided. The cleaning assembly comprises of at least one distribution tube provided with at least one nozzle arranged to spray cleaning substance onto the surfaces of the cooling and/or heating units. The cleaning assembly is preferably in fluid communication with means for heating the cleaning substance. The means for heating is preferably a heat exchanger which is heated by the cooling system of the vehicles engine. Alternatively the cleaning assembly is connectable to an external source of cleaning substance, a pressurized replaceable container of cleaning spray or foam, or to a steam apparatus, or combinations of these.
In a further embodiment the cooling unit and/or heating unit comprises of a plurality of coils and a plurality of heating/cooling flanges attached to the coils, and the distribution tube is arranged to extend through at least a portion of the plurality of flanges. The distribution tube preferably extends through at least a portion of the plurality of flanges and is provided with nozzles in the spaces formed between two adjacent flanges.
The method according to the present invention comprises the steps of:
Alternatively the cleaning substance is heated to steam in a steam apparatus. Thanks to the inventive apparatus, system and method, micro-organism and dirt can be effectively removed from primarily the heating and cooling units of the heating/cooling system of a vehicle. Thus the quality of the air in the vehicles interior will be significantly improved.
The invention will now be described in detail with reference to the drawing figures, in which
a) is a schematic view of a prior art air conditioning unit suitable for use in a vehicle;
a) is a schematic view of a cleaning assembly integrated in an air conditioning unit according to the invention;
The principle of the present invention will be described with reference to the schematic illustration of
Alternatively, the tubes 225′ can be provided on the surface of the evaporator 200, as shown in a side-view of a cooling unit and a cleaning assembly in
The growth of micro-organism and the build-up of particles are, as described in the background section, in most cases worst on the evaporator. Also other parts of the air conditioning unit 200 may be exposed to similar problems, in particular the heating unit. The heating unit is typically realized by a radiator fed with water from the engines cooling system. The heating radiators principle construction is very similar to that of the evaporator and also the heating radiator may be provided with a cleaning assembly according to the above described. The cleaning system for the heater radiator is preferably fully integrated with the cleaning system for the evaporator and utilize the same feeding duct etc. In one embodiment of the present invention, illustrated in
As appreciated by the skilled in the art the design of the evaporator 200 (cooling unit) and heater radiator (heating unit) may differ substantially depending on its intended use, the space provided in the vehicle, the cooling media etc. The cleaning system according to the invention will have to be adapted accordingly and also to the cleaning substance and the used pressure. Such adaptations include, but is not limited to the number of, and the shape of, the nozzles 230. In certain applications the nozzles may be in the form of simples holes, typically in a large number, in the distribution tubes 225. In other applications a more elaborate nozzle design is preferable. One type of nozzles which can be advantageous to utilized are moving nozzles, which are arranged to swing from side to side and/or up and down by the liquid pressure. Such nozzle arrangements are known and commercial available.
In a preferred embodiment according to the present invention, the cleaning assembly 220 is comprised in a cleaning system which utilizes heat produced within the vehicle to heat the cleaning substance, preferably heat from the engines cooling system is utilized, but also other types of excess heat for example from the exhaust gases may be utilized. The cleaning system is schematically shown in
The housing is provided with at least one drainage 342 positioned at the bottom of the air conditioning unit and arranged to collect the cleaning substance that has emerged from the nozzles and poured down mainly from the evaporator 200 and the heat radiator 232. The drainage may advantageously be connected to the storage tank for reusing the cleaning substance. Alternatively the used cleaning substance is discarded.
The cleaning system will also typically be provided with a plurality of valves and adjustment means (not shown) in order to achieve suitable flows and pressures and to start and stop the cleaning process. The process is preferably controlled by microprocessors and in them executed functions. This functionality is preferably incorporated and integrated with the vehicles controlling system.
Additionally the housing is preferably equipped with first and second dampers 345, 350, which are closed during a cleaning operation in order to prevent the cleaning liquid, spray or moist to enter into the passengers compartment or to reach parts of the air conditioning unit which are not suitable to be exposed to the cleaning substance, e.g. the fan and the air filter. The cleaning system may be designed not only to clean the evaporator and/or the heating unit, but also other parts of the heating/cooling system of the vehicle. Distribution tubes 225 and nozzles 230 may be provided in and directed towards other parts of the heating/cooling system, e.g. towards the inside of the dampers, and not at least towards the housing 205 itself.
In another embodiment the storage tank 305 is provided with a heating device 355, preferably a immersion heater 355. The purpose of the heating device is to heat the cleaning substance if the heat transferred from the engine via the heat exchanger 325 will not suffice. Alternatively the heating device 355 may be the only source of heat, in which case the heat exchanger 325 and the tubing system that connects the heat exchanger with the engines cooling system is omitted. This can be a favourable solution in vehicles that are not powered by combustion engines, for example electrically or by gas turbine powered cars.
In a preferred mode of operation, the cleaning system according to the invention is used in a method which comprises the steps of:
This can be arranged by a dedicated evacuation duct and suitable valves to direct the airflow out from the vehicle. Alternatively, the fan may be driven in the opposite rotational direction compared to its normal rotation, giving a flow of air away from the passengers compartment.
The cleaning fluid in the storage tank needs to be refilled periodically. The storage tank 305 for the cleaning substance is preferably made of transparent or semi-transparent material similar to what is commonly used for the coolant and the windshield washer fluid, for easy inspection. The maintenance of the cleaning system will be similar to these other fluid system of vehicles. As well known in the art, different types of automatic detection systems giving indications on the amount of liquid remaining in the storage tank are available.
In a further embodiment of the cleaning system, schematically illustrated in
In yet a further embodiment, schematically illustrated in
The cleaning system according to the embodiment of invention that utilizes the replaceable container 505 may be used in a method which comprises the steps of:
In an alternative embodiment the heat exchanger is replaced by a steam unit that produces pressurized steam. The steam pressure is preferably such that no other means for pressurization or circulation is needed in the cleaning system. A steam apparatus may also be used in combination with the a heat exchanger or other means of heating. In this case the cleaning substance is preheated by the heat exchanger, typically to a temperature below 100°. An amount of the preheated cleaning substance is then converted to steam in the steam apparatus. Steam is very effective for sanitizing and disinfection; even with a small amount of steam an almost autoclaving effect may be achieved. The required amount of steam will vary depending on the size and the design of the air conditioning unit. For a regular car air conditioning unit the steam from less than 1 litre of cleaning substance will in most cases suffice. Hence the steam apparatus can be made relatively small and not required extensive amounts of energy for producing the steam, especially not if the cleaning substance has been pre-heated, in a heat exchanger, for example. The steam apparatus may be heated electrically, via exhaust gas, or with excess heat from the compressor of the air conditioner unit, for example.
Given in
The invention has here been described with embodiments and examples relating to ground based vehicles such as cars and trucks. As appreciated by the skilled man, the invention may equally well be utilized in the heating/cooling systems of other types of vehicles such as aircrafts and boats as well as stationary air conditioning units.
A presumed main use of the apparatus and method according to the present invention is to effectively improve the conditions in the compartment of the vehicle in its everyday use. Another use of the invention is in the case there a vehicle has been contaminated with e.g. bacteria or virus during operation in an area that has been subjected to a biological attack or an outbreak of extreme nature. The disinfection of the vehicle will be greatly simplified with the present invention as parts, otherwise not easily accessible, can be disinfected effectively.
From the invention thus described, it will be obvious that the invention may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended for inclusion within the scope of the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 0302793-5 | Oct 2003 | SE | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/SE04/01515 | 10/19/2004 | WO | 4/19/2006 |
| Number | Date | Country | |
|---|---|---|---|
| 60512087 | Oct 2003 | US |
