FI72797C - The exhaust device. - Google Patents

Description

72797 1 Exhaust system Fränluftsanordning 5

The invention relates to an exhaust air device, in particular for large kitchens or the like, the exhaust air device comprising an outer jacket, an exhaust duct with at least one inlet or grease filter unit, a gaseous pollutant collection chamber and a blowing chamber in the vicinity of is adapted to induce a blowing jet, the control plate of which is adapted to guide towards the suction opening or the grease filters.

15 Ventilation in commercial kitchens, grill bars or the like is known to be difficult to control. The kitchen appliances release various waste heat loads, such as carts, steam, etc., which should be controllable in order to achieve successful ventilation.

20 Ventilation in commercial kitchens can be understood as process ventilation.

Catering equipment in a commercial kitchen is unclean air and. Good indoor climate conditions can only be achieved if it is possible to prevent the spread of the released contaminants into the living area of the kitchen and especially into the breathing air zone.

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Today, the above factors have been taken into account and catering equipment has been developed very intensively. The current equipment aims to remove the generated waste heat and dirty air so that no waste heat and dirty air can spread to the kitchen at all. Such devices 30 are, for example, washing machines and ovens, in which the generated vapors and carts are removed directly from inside the device to the exhaust air duct system. In this case, however, the so-called closed system.

However, lime kitchen appliances cannot be connected directly to the out-35 air duct system without affecting the working conditions of the kitchen. Such appliances include, for example, cookers, pots, grills, grills, frying pans and frying pans. The contaminants released from these devices often enter the breathing zone of the workers, thus deteriorating the working conditions. The distribution of fresh air to the breathing air zone is often a superior task because contaminants get mixed with the supply air before the supply air has reached the workers ’breathing-5 air zone. Efforts have been made to eliminate the above-mentioned disadvantages by building a so-called steam hood above kitchen appliances, but the operation of currently known steam hoods is unsatisfactory. The operation of the steam domes depends on their enclosure load, shape, front area, amount of exhaust air and the location of the suction opening. In addition, the above 10 factors are interdependent.

Recommended face velocities have been mentioned in the literature for various local removal sites. In large kitchens, it is recommended to have a front surface height, ie the so-called the capture rate is 0.25 to 0.7 m / s / end area of the kitchen hood 15. At a flow rate of 0.25 m / s, only the so-called slow flows that contain little heat and steam. As convection increases, higher capture rates are required.

Practice has shown that the above values cannot be used in the design, as the volumes of exhaust air would increase to an unreasonable level, so that the required replacement air cannot be drawn into the kitchen space without draft. In this case, the designers have, at their discretion, reduced the exhaust air volumes, which has made the air volumes used in the commercial kitchen feasible.

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When the front surface speed is reduced, the result is that part of the polluted kitchen air can escape into the breathing air zone due to the so-called reduction in the capture rate. In this case, the kitchen hood no longer works, whereby the humidity and temperature gradient of the air in the kitchen space 30 becomes unfavorable. This situation described above still prevails in the currently known deaeration equipment for commercial kitchens.

With regard to the state of the art, reference is made to Finnish Patent No. 58971, U.S. Patent 4,286,572 and Swedish Patent Publication No. 7904443-4, 35 which present some current solutions known from the prior art.

3 72797 1 There are numerous drawbacks to the currently known solutions. Solutions are usually oversized in terms of exhaust air and edge blowing volumes. The known solutions provide a blow jet with an unsatisfactory shape. Likewise, the flow field is unfavorable and the internal design of the edges of the robe and 5 is unsatisfactory. In addition, in currently known solutions, air volume control is difficult to implement. Furthermore, currently known solutions do not have the possibility to adjust the grease filters, which could affect the filtration efficiency of the grease filters.

The object of the invention is to provide an improvement on the corresponding solutions currently known. The objects of the invention are achieved by an exhaust air device, which is mainly characterized in that the blowing openings below the baffle are adapted to induce a secondary air jet, which is adapted to impulse is adapted to be substantially extinguished before entering said inlet or grease filter.

Other features of the blowing device according to the invention are set out in claims 2-6.

Numerous significant advantages are achieved with the exhaust air device according to the invention. Firstly, the solution according to the invention provides the smallest possible amount of blowing, but nevertheless a very high impulse and the desired turbulence. In the solution according to the invention, a so-called the mixing factor is very high. According to the invention, the controlled air flow interrupts the rising so-called convection currents. In the solution according to the invention, the escape of contaminants from the exhaust air device 30 into the living area of the workers is prevented. The solution according to the invention also offers the operating personnel the possibility to increase and correspondingly reduce the amount of blowing and thus to control the incoming air jet by changing the air flow fields prevailing in the kitchen.

In the solution according to the invention, the incoming air jet can be dimensioned in such a way that the air jet prevents the effect of interference turbulences, which generally occur below the device according to the invention, on the final result.

72797 Ί In the solution according to the invention, it is also possible to directly minimize the amounts of air used and still achieve the desired result. In the solution according to the invention, the design of the exhaust air edges ensures a laminar flow from the edges inwards. Likewise, in the solution 5 according to the invention, the effect of the radiant heat can be substantially reduced.

The invention will be explained in detail with reference to an embodiment of the invention shown in the figures of the accompanying drawings, to which, however, the invention is not intended to be exclusively limited.

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Figure 1 shows a schematic side view of a preferred embodiment of an exhaust air device according to the invention.

Figure 2 shows a section along the line II-II in Figure 1.

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Figure 3 shows detail A in Figure 1 on a larger scale.

Figure 4 shows Figure 3 seen from direction B.

Fig. 5 shows on a larger scale Fig. 1, which shows the air flows of an exhaust air device according to the invention.

Figure 6 shows Figure 5 seen from direction C.

Fig. 7 shows a section along the line VII-VII in Fig. 6.

In the embodiment according to Figures 1-4, the exhaust air device according to the invention is generally indicated by reference numeral 10. In this embodiment, the exhaust air device 10 comprises an outer jacket 11, an exhaust chamber 12, 30 a gaseous pollutant collection chamber 25 and a blow chamber 18. As shown in Figure 1, the exhaust chamber 12 is provided with one or with grease filter units 13. Of course, instead of grease filter 13, there can also be only a suction opening. Reference numeral 14 denotes a grease chute and a collection box. The grease filter filters 13 are provided with a control damper 15, by means of which the amount of air flow through the filters 13 can be adjusted. The exhaust chamber 12 further comprises, as is known, a connection 16 which communicates with the exhaust air duct 5 72797 1 and a control damper 17 by means of which the amount of air flowing into the duct can be adjusted. The damper 17 can of course also be a fire damper. The differential pressure measuring points are denoted by reference number 23. The amount of supply and exhaust air can be determined by the differential pressure Δ measured by the differential pressure measuring points 5 23.

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According to the basic idea of the invention, the blowing chamber 18 is provided at its lower part with a plurality of blowing openings 20 adapted to provide the blowing air with the desired output pulse according to the invention.

The blow chamber 18 comprises a connection 19 which communicates with a supply air duct system (not shown) and said connection is provided with a control damper 24 which can be operated by a drive 22 in the vicinity of the blow openings 20.

15 As shown in Figures 1-4, the air vents 20 and the air baffle 21 arranged above the air vents are adapted to affect the incoming air flow so that the desired output impulse is achieved and the directional air jet is adapted to go out before .

Thus, the solution according to the invention proceeds with the procedure of Figures 5-7; so that in the proximity zone indicated by reference numeral 34 in Fig. 5, the incoming air jet is formed so that its output pulse is very large. It should be noted that the employee works below the short-range 34. In addition, this actual main shower, the so-called the carrier jet 31 is adapted to form turbulent regions 32. As can be seen from Figure 5, the turbulent regions 32 of the main jet 31 cause only a slight vacuum in region 33. Such a sub-30 pressure does not produce any detrimental effect.

The inner surface 18a of the blow chamber 18 is preferably an uninsulated surface which acts as a heat transfer surface for recovering the heat contained in the air to be cleaned as well as heat radiated by possible other heat sources 35 and transferring the recovered heat to the supply air 18 in the blow chamber.

The nozzles 20 according to the invention are dimensioned so that the distance between the nozzles is preferably at least about three times the diameter of the nozzles. In this case, the desired effect according to FIG.

Only one preferred embodiment of the invention has been described above, and it will be apparent to those skilled in the art that numerous modifications may be made thereto within the scope of the inventive idea set forth in the appended claims.

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Claims (6)

72797 Exhaust air device, in particular for large kitchens or the like, the exhaust air device (10) comprising an outer jacket (11), an exhaust chamber (12) with at least one inlet or grease filter unit (13), a gaseous contaminant collection chamber (25) and a blow chamber (18), in the vicinity of which a guide plate (21) is arranged, and in which the blowing openings (20) of the blowing chamber of the exhaust air device are adapted to induce a blowing jet (31), the guide plate (21) being arranged to guide towards the suction opening 10 or grease filters (13), characterized in that the blower openings (20) located below the baffle are adapted to induce a second-secondary air jet from all sides of said blower openings (20) to act in their entirety in the proximity zone (34) and to provide said induced blow jet (31) with the most efficient output adapted to be substantially extinguished before said inlet or grease filter (13) sa apumistaan. 1 Claims Exhaust air device according to Claim 1, characterized in that the blowing openings (20) are adapted to blow air in such a way that the harmful kitchen air containing the contaminants is immediately absorbed in the vicinity of the blowing openings (20). Exhaust air device according to Claim 1 or 2, characterized in that the distance between the blowing openings (20) is greater than their diameter, preferably at least about 3 times the diameter of the blowing openings (20). Exhaust air device according to one of Claims 1 to 3, characterized in that the grease filters (13) are provided with a control damper 30 (15) by means of which the air flow through the filters can be adjusted. Exhaust air device according to Claim 4, characterized in that the control damper (15) is slidably arranged next to the grease filters (13) on the supply air side relative to the filters. 35 72797 Exhaust air device according to one of Claims 1 to 5, characterized in that the inner surface (18a) of the blowing chamber (18) is adapted to act as a heat transfer surface for recovering and transferring heat from the air to be cleaned and other heat sources to the blowing air (18). 10 15 20 25 30 35 7 9 7 9 7