The invention relates to a hood extractor for extracting contaminated air from appliances.
In commercial kitchens contaminated air produced by cooking appliances is extracted by a hood extractor mounted above the appliances. The hood extractor comprises a grease filter, which collects grease and dust from the air. Additionally, the hood extractor may comprise a UV light source emitting UV light, which breaks the grease molecules into small particles, which are removed from the hood extractor with the air flow.
Despite the use of the grease filter and the UV light, the extractor surfaces collect grease and dust, which has to be removed periodically. This is done by spraying washing agent mixed with water into the extractor through nozzles. Typically the spraying system is realized by fitting nozzles to pipes arranged inside the extractor. This construction, however, needs a lot of space inside the extractor, which in turn increases the dimensions of the extractor and air pressure drop caused by the extractor. Further, there is a gap between the pipe and the extractor wall, which collects grease and dust, which is difficult remove by washing. Also the spraying angle of the nozzles is not always an optimal, which weakens the washing result.
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This object can be achieved by a hood extractor according to independent claim 1.
The hood extractor according to the invention comprises a housing through which air to be extracted is arranged to flow, an air inlet for conducting air into the housing, an air outlet for removing air from the housing, a grease filter arranged in the housing between the air inlet and the air outlet and an arrangement for spraying washing agent into the housing. The arrangement for spraying washing agent comprises at least one duct and nozzles for spraying washing agent from the duct into the housing. The nozzles are formed in a wall of the duct. The nozzle comprises a nozzle opening in the wall of the duct, a spin plate having an S-shaped opening and arranged against an inner surface of the wall of the duct so that the nozzle opening and the S-shaped opening are facing each other, and a block plate arranged against the spin plate so that both ends of the S-shaped opening are uncovered.
The hood extractor according to the invention causes a low air pressure drop, since the nozzles are formed in the wall of the duct and therefore do not extend outwards from surface of the duct.
According to an embodiment of the invention the duct is attached to or integrated into the wall of the housing or installed with a small gap between it and the wall of the housing. This further reduces the air pressure drop in the extractor. If the duct is attached or integrated into the wall of the housing, there is no gap between the duct and the wall of the housing and no grease and dust can go therebetween. This makes it easier to wash the surfaces of the hood extractor efficiently.
In the following the invention will be described by way of examples with reference to the accompanying drawings, in which:
The hood extractor 1 comprises a housing 2, through which air to be extracted is arranged to flow. The housing 2 is provided with an air inlet 3 for conducting air into the housing 2 and an air outlet 4 for removing air from the housing 2. The air outlet 4 is connected to an exhaust duct, which conducts air to the atmosphere. Air is sucked through the housing 2 by a fan installed downstream of the air outlet 4. The hood extractor 1 comprises a hood 18, which prevents contaminated air from escaping to the kitchen and directs air toward the air inlet 3. The front wall 15 of the housing comprises a baffle 12 having a front surface 13, which directs the air flow downwards after passing through the air inlet 3.
A grease filter 7 for collecting grease from the air flow is arranged in the housing 2 between the air inlet 3 and the air outlet 4. The grease filter 7 can be a mesh or baffle filter or a hybrid of mesh filter and baffle filter. The grease filter 7 is installed between a front wall 15 and a rear wall 19 of the housing 2 so that all the air flowing from the air inlet 3 to air outlet 4 passes through the grease filter 7.
The hood extractor 1 further comprises a UV light source 20, which emits UV light. UV light breaks the grease molecules into small particles, which are removed from the hood extractor 1 with the air flow. The UV light source 20 is installed in the housing 2 downstream of the grease filter 7.
In use the housing 2 surfaces collect grease and dust, which has to be removed periodically. For this purpose the hood extractor 1 comprises an arrangement for spraying washing agent into housing 2. Washing agent can be water, pure washing agent or mixture of water and washing agent. The arrangement for spraying washing agent comprises at least one duct 5 attached to or integrated into a wall of the housing 2 and nozzles 6 for spraying washing agent from the duct 5 into the housing 2. The duct 5 is arranged in the housing 2. The duct 5 can be attached directly to the wall of the housing 2 or installed with a gap between it and the wall of the housing 2. The width of the gap is less than 50 mm, typically less than 20 mm. Also this gap can be washed with nozzles 6, for example the nozzles 6 can be formed in a wall of the duct 5, which faces the wall of the housing 2. Washing agent is conducted into housing 2 along the duct 5 and sprayed by nozzles 6 into the housing 2.
The duct 5 can be attached to or integrated into the wall of the housing 2 upstream of the grease filter 7. A front wall 15 of the housing 2 comprises a baffle 12 having a front surface 13 for directing the air flow downwards after passing through the air inlet 3. The duct 5 can be attached to or integrated into or arranged on a rear surface 14 of the baffle 12. Additionally or alternatively, the duct 5 can be attached to or integrated into or arranged on an inner corner between a bottom wall 21 and the rear wall 19 of the housing 2. Additionally or alternatively, the duct 5 can be attached to or integrated into or arranged on the wall of the housing 2 downstream of the grease filter 7. For example, the duct 5 can be attached to or integrated into or arranged on an inner corner between the front wall 15 or rear wall 19 and a top wall 16 of the housing 2.
The duct 5 has an angular cross-section. The duct 5 comprises a rear wall 22, which is arranged against the wall of the housing 2. Alternatively, the wall of the housing 2 may form the rear wall of the duct 5. The duct 5 comprises at least three walls, typically 4-6 walls, which are arranged at an angle with respect to each other. The angle between the walls can be selected so that washing agent can be sprayed at an optimal angle from the nozzles 6. The walls of the duct 5 are flat. At least two of the walls are provided with nozzles 6 for spraying washing agent into the housing 2. Typically, the walls, which are directed towards the interior of the housing 2, are provided nozzles 6 for spraying washing agent into the housing 2.
According to an embodiment of the invention shown in
The distance between adjacent nozzles 6 in the wall of the duct 5, as measured in the longitudinal direction of the duct 5, is 100-200 mm, typically 130-170 mm. The pressure of the washing agent in the duct 5 is below 15 bar, typically 8-10 bar.
The hood extractor 1 further comprises a filter nozzle 17 for injecting washing agent directly into the grease filter 7. The filter nozzle 17 is arranged to inject washing agent into the grease filter 7 from a filter end which faces the wall of the housing 2. By means of the filter nozzle 17 the grease filter 7 can be cleaned efficiently.
The hood extractor is also provided with a drain opening 23, through which washing agent is removed from the housing 2. The drain opening 23 is formed in the bottom wall 21 of the housing 2.
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