HENDRIKSEN, Henrik (Møllegaardsvej 3, Nykøbing Mors, DK-7900, DK)
| CLAIMS 1. Method for combating of formation of and propagation of bacteria cultures and microorganisms etc. on the condenser surfaces (28) in refrigeration plants/units (4), particularly in refrigeration plants/units (4) in cooling containers where the cooling air and the condenser surfaces during operation are illuminated with UV light in combination with a filter (12) treated with titanium oxide, c h a r a ct e ri z e d in, that the cooling air and the condenser in a period immediately subsequent to operation stop of the refrigeration plant/unit is radiated with electromagnetic radiation generated by a high frequency generator. 2. Method according to claim 1, c h a ra ct e r i z e d in, that the wave length of the UV light is located within the area 200-300 nm, typically within the range 240-270 nm, and preferred the wavelength is located within 250-260 nm. 3. Method according to claim 2, c h a ra ct e ri z e d in, that the UV light has a wavelength at 254 nm. 4. Method according to any one of the claims 1-3, c h a ra ct e r i z e d in, that the strength of the UV light source is located within the area 5-100W, typically within 25-75W and preferred within 55-65W 5. Method according to any one of the claims 1-4, c h a ra ct e r i z e d in, that the strength of the UV light source is approximately 60W. Method according to any one of the claims 1-5, c h a ra c t e r i z e d in, that the UV light source consists of a tubular light source. 7. Method according to any one of the claims 1-6, c h a r a c t e r i z e d in, that the UV light source is arranged in a distance from the filter with titanium oxide within the range 1-200 mm, typically 20-140 mm and preferred within the range 40-60 mm. 8. Device (2) for exercising of the method according to any one of the claims 1-7, c h a r a c t e r i z e d in, that it comprise a frame (6) for mounting in immediate vicinity of the condenser (28), said frame (6) comprising a filter (12) saturated with titanium oxide, and a UV light source (20) in a distance from the filter (12), said light source (20) being arranged with a control unit in a manner that the UV light source preferably is activated and switched off together with the refrigeration plant/unit (4). 9. Device (2) according to claim 8, ch aracte rized in, that the UV light source consists of a tubular UV light source (20) with a strength located within the range 5-100W, typically within 25-75W and preferred within 55-65W. 10. Device (2) according to any one of the claims 8 or 9, ch a racte- r i z e d in, that the wavelength of the UV light emitted from the tubular light source is located within the range 200-300 nm, typically within the range 240-270 nm, and preferred the wavelength is located within 250-260 nm. 11. Device (2) according to any one of the claims 8-10, c h a r a c t e - r i z e d in, that the wavelength of the emitted light from the tubular UV light source (20) is 254 nm. 12. Device (2) according to any one of the claims 8-11, ch a racterize d in, that the UV light source (20) is arranged in a distance from the filter (12) with titanium oxide within the range 1-200 mm, typically 20-140 mm and preferred within the range 40-60 mm. 13. Device (2) according to any one of the claims 8-12, c aracterized in, that the UV light source (20) is arranged in a distance at 50 mm from the filter (12) with titanium oxide. 14. Device (2) according to any one of the claims 8-13 for the exertion of the method according to claim 1, ch a racterized in, that the frame (6) further comprises a high frequency generator (24) which is connected to a control unit being such arranged, that the high frequency generator at start up of the refrigeration plant/unit is activated in a pre-set period and subsequently is turned off. 15. Refrigeration plant/unit (4) for performing the method according to claim 1, characte rized in, that it near by the condenser area comprises a de- vice (2) for combating of formation of and propagation of bacteria cultures and microorganisms etc. on the condenser surfaces (28) according to any one of the claims 8-14. 16. Cooling container with refrigeration plant/unit (4), c h a r a c t e r i z e d in, that the refrigeration plant/unit (4) near the condenser area comprises a device (2) for combating of formation of and propagation of bacteria cultures and microorganisms etc. on the condenser surfaces (28) according to claim 15. |
The present invention relates to a method and device for the combating of formation and propagation of bacterial cultures, viral, fungal cultures, mildew, and microorganisms etc. on the condenser surfaces in larger refrigeration systems, in particular in refrigerating plants/units in cold containers wherein the cooling air continuously is irradiated with UV-light in combination with a filter treated with titanium oxide during operation, and a device for performing the method according to the invention. The invention also comprises larger cooling plants comprising the device for exertion of the method according to the invention. Larger cooling systems operates typically by cooling air which has been cooled to a preferred temperature is circulated and re-circulated by a fan in a completely or partially sealed compartment, wherein are arranged cargo the shelf life of which is depending of being cooled down to a certain temperature. An example on this is cooling containers which comprises an insulated container with an independent cooling system which is typically arranged in one end of the cooling container, where the cooling air is circulated by fans over the condensers and via ducts out into the enclosure of the cooling container, whereby the cargo arranged therein is cooled down to a determined temperature, e.g. during transportation.
In the following specification of the invention the invention is for simplicity sake described together with a cooling container, but that should not limit the invention, since the principals for it, is useable in many other relations as well in larger cooling plants with circulation of cooling air being circulated over a condenser, and common cooling plants and cold stores. The invention is thus to be considered in its widest perspective in relation to cooling plants and cold stores.
However infection of the cold-storage room with bacterial and fungal cultures etc. derived from the goods arranged in the cold-storage room can ' t be avoided, also due to the fact that persons are operating in the cold-storage rooms during loading and unloading thereof. Cooling containers are used for transport of all goods to be cooled down to avoid tainting, examples on that is meat, fruit, offal waist etc. When the cooling container reaches its destination the container will be opened and all goods unloaded. Subsequently the container will be cleaned with a steam cleaner after which it will be declared as "clean", and be loaded with other goods. However, the problem is, that the container is actually not "clean" since the condenser in the cooling plant has not been steam cleaned, as the cooling plant can ' t be cleaned in normal manner using steam because it is surrounded by electronic equipment, and can ' t endure either high pressure steam nor chemicals. The Danish Institute Of Technology have performed measurement of seed and bacteria in a container lend from Maersk, and the results are scaring, as it shows that the concentration of bacteria on the condensers of the cooling plant are considerable, and thus forms a kind of "quick start up" for the propagation of bacteria etc. next time the cooling container is used for transportation of goods.
An example on this is when fruit are put in a box and their skin or rind are pressed against each other, a gas called Ethylene is emerged. Ethylene initiates at the same time the contamination process. Tests made in a brand new container has shown, that after approximately 8 days (which is not unrealistic long time when fruit are transported from one part of the world to another), plate counts larger than 1.400 could be measured inside the storage room of the container, but plate counts larger than 16.000 on the condenser in the container.
Solving this problem there could be operated with solutions comprising a manual, more careful performed cleansing of the condensers in the cooling containers, but it does not change the fact, that there will be formations of other/new bacteria during transportation of easy pernicious goods in the container, and the manual cleaning of the condensers of the cooling plant of the cooling container will thus have to take place subsequent the end of every transportation of goods. Fur- ther the "human factor" must be taken in mind, where it not always is secured that the cleaning is performed uniformly and with same quality. From WO 2005 044446 A1 (YORK INT CORP) is known a method for combating of propagation of bacteria cultures and microorganisms etc. on the condenser surfaces in cooling plants, especially in cooling plants in cooling containers, where the cooling air and the condenser surfaces during operation are conti- nuously irradiated with UV-light in combination with a filter treated with titanium oxide. The method has shown to be efficient, and inhibits the propagation of said damaging bacteria cultures, seeds, and micro organisms, and has contributed to a longer keeping qualities for foodstuffs transported in e.g. cooling containers. However, the lack of the above mentioned efficient cleaning of the cooling containers result in that the irradiation with UV-light are not as efficient as preferred, since the UV-irradiation only operates together with the operation of the cooling plant, in the cooling container, which means that non operative periods of the cooling container after normal cleansing, results in formation and propagation of not wanted seeds, bacteria and microorganisms which will be spread into the cooling room of the cooling container, when the fans of the cooling plant are started, which is not preferred.
It is thus the object of the invention to provide a solution of the problem above, so that formation and propagation of bacteria cultures, viral, fungal cul- tures, mildew, and microorganisms etc. on the condenser surfaces in larger cooling plants, especially in cooling plants in cooling containers, is prevented, or in all conditions are reduced approximately to zero.
This object is achieved by the method mentioned in the preamble, for com- bating of formation and propagation of cultures of bacteria, viral, fungal cultures, mildew and microorganisms etc. on the condenser surfaces in larger refrigeration systems, in particular refrigeration plants in cooling containers, where the cooling air and the condenser surfaces during operation of the refrigeration plant, are continuous radiated with UV-light in combination with a filter treated with titanium oxide, characterized in, that the cooling air and the condenser in a period immediately subsequent to operation stop of the refrigeration plant is radiated with a high frequency generator.
The high frequency generator has the effect that its powerful electromagnetic radiation leads to that all biological material in the radiation field is destroyed, and thus the bacterial cultures, fungal cultures etc. The radiation with the high frequency generator is made only in a short period after taking the refrigeration plant in operation, then it is switched off while the radiation with the UV-light continues until the container is emptied, or the operation of the refrigeration plant is suspended.
It shall be noted that the inventor is aware of that it is well known to use UV light in combination with Titanium oxide for killing bacteria cultures etc.
Studies performed of the Danish Institute of Technology and reported in 2009 in the report: "Study of killing effects against microorganisms using the Clean Air System for purification of the circulated air and surfaces in a cooling container" shows as well a significant reduction of colony count, as content of mold and yeast in the cooling air, using the method, and the suitability to counteract formation and propagation of bacteria cultures, viral, fungal cultures, mold and micro organisms etc. on the condenser surfaces in larger refrigeration plants, and among these in particular in refrigeration units in cooling containers is thus documented.
However it is not known to use electromagnetic radiation generated by a high frequency generator in combination with the known technology comprising radiation with UV-light and titanium oxide, to fight of formation and propagation of bacteria cultures etc. on the condenser surfaces in larger refrigeration plants, in par- ticular refrigeration units in cooling containers, and the measures made by the Danish Institute of Technology shows clearly, that the method according to the invention, where electromagnetic radiation generated by a high frequency generator in a shorter period subsequent to start of a refrigeration plant, followed by utilization of a filter coated with titanium oxide in combination with a UV-light source, indicates a solution of the known problems concerning formation and propagation of bacterial cultures, viral, fungal cultures, mildew, and microorganisms etc. on the condenser coil in larger refrigeration systems, in particular in refrigeration units in cooling containers, which can only be removed by manually performed cleaning work. Thus, the electromagnetic radiation contributes so significantly to the killing of bacterial cultures, fungal cultures, virus, mold, etc. at startup of the refrigeration system, and they are therefore not in previously known levels spread with the cooling air to the detriment of the foodstuff arranged in the cooling plant or the cooling container.
The continuous radiation by the UV-light source in combination with the filter containing titanium oxide leads partly to counteract formation and propagation of bacterial cultures, viral, fungal cultures, mildew, and microorganisms etc. on the condenser coil in larger refrigeration systems, in particular in refrigerating plants in cold containers, so those surfaces does not contribute to spread said cultures and organisms when the container is loaded with new products/goods, but simulta- neously also that already present bacterial cultures, viral, fungal cultures, mildew, and microorganisms etc. in the goods loaded into the cooling container, are not spread to such an extent as would otherwise be the case if the continuous illumination with UV light in combination with the filter with titanium oxide was not made, leading to an increased durability of those products/goods.
A further advantage by the method according to the invention is, that bacteria are not spread so easily between continents, provided that the disinfection unit is used. In this context i may be stated that approx. 1 million refrigerated containers are in use round the clock worldwide.
Also odor problems associated with the containers are eliminated using the disinfection unit according to the invention. For the moment it is so, that if there were citrus fruits in a container, it is not possible immediately after to transport cocoa beans in the same container, as the cocoa will absorb taste of previous trans- ported products. This problem is also solved using the method according to the invention.
It is preferred that the wavelength of UV-light is located within the area 200- 300 nm, typically within the range 240-270 nm, and preferred the wavelength is located within 250-260 nm.
In a particularly preferred practice of the method according to the invention the wavelength of the UV-light is 254 nm. Experiments has shown, that the strength of the UV-light source advantageously may be located within the area 5-100W, typically within 25-75W and preferred within 55-65W.
In a particularly preferred practice of the method according to the invention the strength of the UV-light source is approximately 60W. For the sake of achieving the widest possible dissemination of the light, and with the intent to radiate the largest possible part of the filter with titanium oxide, it is preferred that the UV-light source consists of a tubular lamp. The distance between the filter with titanium oxide and UV light source may be located within the range 1-200 mm, typically 20-140 mm, and preferred within the range of 40-60 mm.
A device for exertion of the method according to the invention comprises a unit consisting of a frame for mounting in immediate vicinity of the condenser of the refrigeration plant, said frame comprising a filter saturated with titanium oxide and an UV-light source in a distance from the filter, and said light source being arranged so with a control unit, that the UV-light source is preferably activated and switched off together with the refrigeration plant/unit.
In the case of refrigerated containers has proved that it is advantageous to use two units of appropriate dimension arranged in the ducts of the refrigeration unit of the refrigerated container in each side near the condensers and fans which circulates the air around inside the container space. The units are furnished as standard elements/frames for installation in all types of refrigerated containers.
It is preferred that the UV light source consists of a tubular UV light source with a strength located within the area 25-100W typically within 40-75W and preferred within 55-65W.
It is further preferred that the wavelength of the UV light emitted from the tubular light source is located within the range 200-300 nm, typically within the range 240-270 nm, and the preferred wavelength situated within 250-260 nm. In a particular preferred embodiment of the unit, the wavelength for the light emitted from the tubular light source is 254nm, which is the wavelength that has proved most effective in combating bacteria, fungi, mold cultures etc.
It is preferred that the UV light source is arranged in a distance from the filter with titanium oxide within the range 1-200 mm, typically 20-140 mm and preferred within the range 40-60 mm. In connection with units suited to be arranged in limited space conditions, such as in the refrigeration unit in refrigeration containers, it is preferred that the UV light source is arranged in a distance of 50 mm from the filter with titanium oxide. Hereby is achieved a reasonable degree of illumination of the filter with tita- nium oxide, while the build-in height of the frame is relatively small.
Starting up a relevant refrigeration plant/unit in which the unit according to the invention is arranged, the use of a high frequency generator is advantageous for eliminating possible occurring larger formations of bacteria cultures, viral, fun- gal cultures, mold and microorganisms etc. on the condenser surfaces and cooling ducts of the refrigeration plant/unit. However is the use of the high frequency generator only necessary when starting up the refrigeration plant/unit. Thus, the frame may advantageously further comprise a high frequency generator connected to a control unit such arranged, that the high frequency generator is acti- vated in a pre-set period at start up of the refrigeration plant/unit, and subsequently it is turned off.
The invention also relates to a refrigeration plant/unit characterized in, that it near the condenser area comprises a device for combat of formation and propaga- tion of bacteria cultures and microorganisms etc. on the condenser surfaces according to the method according to the invention stated in any one of the claims 1- 8, including refrigeration plants/units comprising a unit according to any one of the claims 9-14. The invention relates further to cooling containers, where the refrigeration plant/unit comprises a unit for combating of formation of and propagation of bacteria cultures and microorganisms etc. on the condenser surfaces according to the method according to the invention stated in any one of the claims 1-8, including refrigeration plants/units comprising a unit according to claim 15.
The invention is further explained below with reference to the drawing, wherein
Fig. 1 is a perspective picture of a device for combating of formation and propagation of bacteria cultures and microorganisms etc. on the condenser surfaces in refrigeration plants/units according to the invention, Fig. 2 is a picture of the device shown in fig. 1 build in the refrigeration plant/unit in a cooling container,
Fig. 3A and 3B are respective a section view and an end view of the refrigeration plant in a cooling container, showing where in the refrigeration plant/unit the device shown in fig. 1 and fig. 2 is build in, and
Fig. 4 is a diagram indicating the effect of the device for combating of formation and propagation of bacteria cultures, and microorganisms etc. on the condenser surfaces in refrigeration plants/units based on measures made by the Danish Institute of Technology.
In Fig. 1 is shown an embodiment of a device 2 for combating of formation of and propagation of bacteria cultures and microorganisms etc. on the condenser surfaces in refrigeration plants/units 4, see fig. 3A and 3B.
The device 2 comprises in the shown embodiment a rectangular frame 6 with two long sides 8 and two short sides 10, in said frame 2 is positioned a filter material 12 containing titanium oxide. The short sides 6 of the frame 2 comprises end panels 14, 16 with just formed triangular-shaped cross section. In the end panels 14, 16 are arranged consoles 18 for mounting of a UV light source 20 connected to a not shown power source associated with the refrigeration plant/unit 4 via cables (not shown). To illuminate the entire surface of the filter 22, the UV light source is arranged in a distance from the filter material 12 containing titanium oxide.
On the outer side of at least the one end panel 14 there is further arranged a high frequency generator 24, which also via not shown cables and a timer for switching on and off the power to the high frequency generator is connected to a power source belonging to the refrigeration plant/unit 4.
In fig. 2 is shown how the device 2 for combating formation of and propagation of bacteria cultures etc. on the condenser surfaces in refrigeration plants/units is arranged in the refrigeration plant/unit, near the fan 26 which circulates the cooling air being cooled down when circulated over the surface of the condenser 28.
In fig. 3A and 3B, which is respectively a side-section view and an end view of the refrigeration plant/unit 4 for a cooling container, is shown how the device 2 for combating formation of and propagation of bacteria cultures and microorganisms etc. on the condenser surfaces in the refrigeration plant/unit. As it appears, the refrigeration plant/unit in the shown embodiment is supplied with two units, one in each side of the refrigeration plant/unit.
The device for combating formation of and propagation of bacteria cultures and microorganisms etc. on the condenser surfaces in refrigeration plants/units operates as follows. When the refrigeration plant/unit is connected to a power source and switched on, the UV light source is switched on illuminating as well the filter material 12 as the surface of the condenser surface 28 in the refrigeration plant/unit, and naturally also the air that is circulated around as well in the refrigeration plant/unit 4, as in the therewith connected cooling container (not shown), thereby creating an environment in which the formation of and propagation of bacteria cultures and microorganisms etc. on the condenser surfaces in refrigeration plants/units are inhibited strongly, so that they are eliminated.
Simultaneously with the start up of the refrigeration system, the timer controlling the operation of the high frequency generator 24 is activated. The high frequency generator is then put into operation in a pre-selected time, where the rad- iation stops the development in all occurring organic material in the area around and on the condenser 28. After the expiry of the selected period the high frequency generator 24 is switched off automatically, while the UV light source remains lit until the refrigeration plant/unit 4 is taken out of service. In fig. 4 is a schematic form of bar charts shown the impact of the device according to the invention in connection with an experimental setup in which the device has been built in a refrigeration plant/unit in a cooling container loaded with various fruits and vegetables, and is a reproduction of the results in the report: "Study on the killing effects against microorganisms using the Clean Air purifica- tion system for purification of the circulated air and surfaces in a cooling container" prepared by the Danish Technological Institute, April 2009. Column A shows the amount of bacteria on the surface of the cooling unit after 14 days with the refrigeration system in operation. Columns B and C shows the concentration of bacteria at the left and right side of the cooling element, measured 20 hours after the start of the device to combat the formation of and propagation of bacterial cultures and microorganisms etc. on condenser surfaces in refrigeration systems according to the invention, column D shows the concentration of bacteria in the exhaust air from the cooling system after the start of the device according to the invention, and the "columns" E and F show the concentration of bacteria on the surfaces of the left and right condenser, 20 hours after the setting the device according to the invention in operation.
The measuring results cf. Fig. 4 clearly shows the alleged effect of the device for performing the method according to the invention and will be well qualified for use in the counteract of proliferation and propagation of bacterial cultures in refrigerator plants/units.
It should be noted that the inventor has realized that the invention may adopt other embodiments than the one described and shown in the drawings and that the use of UV light has been applied in other contexts for disinfection, but that does not change the inventive aspect, which is to use this technology in a completely new and unprecedented relationship that can lead to improved product quality of the goods transported in cooling containers or bulk products stored in refrigerators, coolers, etc. Further, the use of the invention also help to counteract the spread of infection, when food is transported between different parts of the world.
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