APPARATUS FOR HUMIDIFYING AIR IN AN AIR DUCT

Abstract

An apparatus for humidifying air in an air duct

The invention relates to an apparatus for humidifying air in an air duct (1), comprising a feeding device for a liquid mist (10) and an air conducting device located upstream of the feeding device in the direction of flow (2). In order to provide advantageous humidifying conditions it is proposed that the air conducting device comprises at least one wing (7) which extends transversely to the direction of flow (2) and has an airfoil profile which is pitched against the direction of flow (2).

Claims

1. An apparatus for humidifying air in an air duct (1), comprising a feeding device for a liquid mist (10) and an air conducting device located upstream of the feeding device in the direction of flow (2), wherein the air conducting device comprises at least one wing (7) which extends transversely to the direction of flow (2) and has an airfoil profile which is pitched against the direction of flow (2).

2. The apparatus according to claim 1, wherein the wing (7) extends parallel to at least one row (6) of outlet openings (5) for the liquid mist (10), which row is oriented transversely to the direction of flow (2), and is arranged at a distance from the row (6) of the outlet openings (5), which distance is perpendicular in relation to the direction of flow (2) and to the row (6) of the outlet openings (5).

3. The apparatus according to claim 1, wherein the wing (7) extends parallel to at least one outlet slot for the liquid mist (10), which slot is oriented transversely to the air duct (1), and is arranged at a distance from the outlet slot which is perpendicular to the direction of flow (2) and to the outlet slot.

4. The apparatus according to claim 2, wherein two wings (7) arranged symmetrically with respect to the direction of flow (2) are provided upstream of least one row (6) of the outlet openings (5) or at least one outlet slot.

5. The apparatus according to claim 2, wherein an inflow profile (9) is provided upstream of the row (6) of the outlet openings (5) or the outlet slot.

6. The apparatus according to claim 1, wherein the pitch angle of the wing (7) or wings (7) is adjustable.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The subject matter of the invention is shown by way of example in the drawings, wherein:

[0012] FIG. 1 shows an apparatus in accordance with the invention for humidifying air in a schematic longitudinal sectional view of the air duct perpendicularly to the axis of the rows of outlet openings;

[0013] FIG. 2 shows a row of outlet openings with a guide device consisting of two wings with an airfoil profile in a sectional view perpendicularly to the row of the outlet openings on an enlarged scale, wherein the flow conditions are schematically indicated by the flow lines;

[0014] FIG. 3 shows a view of a constructional variant corresponding to FIG. 2 with an arrangement of the airfoil profiles which differs in comparison with FIG. 2, and

[0015] FIG. 4 shows an illustration of an air conducting device for a number of outlet openings with only one airfoil profile, which illustration corresponds to FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0016] In order to humidify the air conveyed through an air duct 1 of usually rectangular cross-section, a feeding device for a liquid mist with several parallel distributor tubes 3 extending transversely to the flow direction 2 for a liquid to be misted is provided according to FIG. 1, with which nozzles 4 are supplied, which nozzles are distributed over the length of the tube, oriented in the direction of flow 2 and introduce the respectively pressurised liquid in form of a mist into the air flow. The outlet openings 5 of said nozzles each form a row 6 extending transversely to the direction of flow 2, which are provided upstream with air conducting devices consisting of wings 7 with an airfoil profile, which wings extend parallel to the rows 6 of the outlet openings 5. Said wings 7 can be adjusted with respect to the pitch angle about pivoting axes 8 in relation to the direction of flow 2. The distributor tubes 3 are lined with an inflow profile 9 on the side facing the wings 7, wherein flow passages for the air flow are formed between the associated wings 7 in order to achieve advantageous flow conditions in the injection region of the liquid mist.

[0017] In FIG. 2, the flow conditions are schematically indicated by flow lines in the region of a row 6 of the outlet openings 5 for a liquid mist 10. As a result of the wing arrangement with an airfoil profile whose upper side producing an acceleration of the flow faces the nozzles 4 or the inflow profile 9, flow vortexes detach from the rear edge of the profile which produce a concentration of the injected liquid mist 10. It can be recognised that the vortex axes extend substantially parallel to the rear edge of the profile, i.e. transversely to the direction of flow 2, so that the liquid droplets gripped by said vortex layers are not only intimately mixed with the flow air, but also cover a distance within the air duct 1 as a result of the vortex movement about a vortex axis extending transversely to the direction of flow 2, which distance corresponds to a multiple of the respective longitudinal extension of the air duct 1. This means that within a comparatively short longitudinal section of the air duct 1 a distance can be provided as a result of the special vortex formation for the liquid droplets which is adequate for complete evaporation of the liquid droplets, since intimate mixing of the liquid droplets with the air is ensured by said vortex formation.

[0018] According to the embodiment in accordance with FIG. 3, the wings 7 are oriented in comparison with FIG. 2 with the bottom side of the profile against the row of nozzles or the inflow profile 9, leading to vortex shedding on the profile side facing away from the row of the nozzles. The injected liquid mist 10 is therefore fanned out via the air vortexes, so that different requirements can be met by such a wing arrangement in comparison with the wing arrangement according to FIG. 2.

[0019] FIG. 4 shows that under specific preconditions a wing arrangement on one side can also be useful. Unsymmetrical conditions are achieved with the wings 7 provided on one side of the nozzle arrangement concerning the injection of the liquid mist 10 into the air flow, which can be advantageous in boundary regions of the air duct 1 for example.

[0020] Although it is principally possible to provide an air humidifying device in accordance with the invention with only one row of nozzles, especially advantageous construction conditions are provided by the arrangement of several rows of nozzles, not only concerning the distribution of the nozzles over the cross-section of the air duct 1, but also concerning the dosing of the injected liquid quantity. In order to achieve predetermined humidity content for the air flowing out of the air duct 1, a liquid quantity to be evaporated is required which is dependent on the humidity content of the air flowing into the air duct. The liquid quantity that is injectable via a row of nozzles depends under the given constructional conditions on the liquid pressure to which the individual nozzles 4 are subjected. If only a low liquid quantity is required for achieving a predetermined liquid content of the air emerging from the air duct 1, said liquid quantity can be introduced via a row of nozzles into the air duct, wherein the liquid quantity is dosed via the liquid pressure. If the liquid demand exceeds the liquid quantity that can be introduced under maximum application pressure via a row of nozzles, a further row of nozzles can be supplied with liquid, wherein it is commenced in the two rows of nozzles with minimal pressure required for adequate fine misting of the liquid in order to increase the liquid pressure for both rows of nozzles as required up to the maximum pressure before a further row of nozzles is activated at minimal pressure for covering an additional need for liquid for all rows of nozzles that are used.

[0021] Although according to the illustrated embodiment the liquid mist to be introduced into the air to be humidified is generated in a simple manner by misting the liquid by means of nozzles 4 which can be subjected to a respective pressure, the invention is in no way limited to such a generation of a liquid mist because it is merely necessary to introduce a liquid mist into the area to be humidified. The generation of the mist could also occur by an ultrasonic generator, wherein the feeding device must substantially comprise outlet openings through which the liquid mist is introduced into the air duct 1. The rows 6 of such outlet openings 5 can also be replaced by outlet slots.