FI84573B - BLAOSANORDNING FOER VINDSPRIDNING AV SPAONOR. - Google Patents

Description

, 84573

The present invention relates to a blowing apparatus for use in the manufacture of particle board for scattering chips using wind sorting.

The blowing devices 10 used for this purpose are generally known in various variations. The following basic devices all include, namely, a fan for providing airflow, a blowpipe for directing airflow to the spraying stage, and a flow equalizer located at the mouth of the blowpipe 15 and extending into the cross-sectional area of the wind chamber.

A perforated plate is usually used as a flow equalizer, in which perforations have been made 20 in size and position according to the desired flow result. The plate has been made straight, which has been found to have certain flow problems with respect to the air flow discharged from the perforation. The air discharged from the holes in the edge areas of the cross-section of the wind chamber has had to travel from 25 fans, in the expanding blowpipe, for a longer distance than the air discharged into the flow equalizer from the holes in the central area. As a result, the pressure of the air discharged from the perforation of the edge region of the flow equalizer is lower than that of the air flow discharged from the perforation of the central region.

The phenomenon causes its own problems for the scattering event. The lower pressure in the edge areas of the cross-section of the wind chamber causes transverse flows from the central region to the edge regions. These lateral currents cause a vortex farther in the wind chamber in the chip drop zone, which takes the chips 84573 2 from the edges to the center, resulting in unevenness in the scattering result. In particular, aberrant currents affect the transport of fines.

5 An attempt has been made to solve the problem by influencing the cross-section of the flow openings of the flow equalizer, whereby the flow cross-section of the openings in the edge areas of the wind chamber is constricted. This measure alleviates the differential pressure problem, but this measure brings with it its own problems. The most significant of these new problems is the flow disturbance in the blower, especially in the vicinity of its walls. These flow disturbances lead to the accumulation of contaminants in the recirculated air used as scattering air on the walls of the pu-15 hallway, which prevents or reduces the possibility of using the recirculated air. The recirculated air must be replaced by a recirculated flow from which the dust from the spray has been removed. Choking the flow also causes energy loss.

According to the invention, a solution to this unevenness of the pressure distribution on the outlet side of the flow compensator has been sought from different starting points than before. The invention is based on the harmonization of the length of the air flow paths with respect to the discharge openings in different areas of the flow equalizer. According to the basic embodiment of the invention, the length of the air flow paths is extended in the central region of the flow equalizer by installing a grate structure 30 of plate strips on the outlet side of the flow equalizer. The choice of the width of the strips is specifically aimed at the central region of the flow path, which is the same as the flow path defined by the opposite-side wall of the blow-pipe 2 corresponding to 35.

3,84573

The specific features of the invention are defined in the appended claims.

The invention will be explained with the aid of the accompanying drawing, if-5 sa

Figure 1 shows the apparatus according to the invention in a side, schematic sectional view, 10

Figure 2 shows a top view of the apparatus according to the invention, in principle, and Figure 3 shows a cross-sectional view of the device from direction A as seen in Figure 1.

The drawings show the conventional basic parts of the wind-sprinkler-20 cutting equipment, i.e. the sprinkling platform 6, which advances at a constant speed and on which the wind-sprinkled chip stream lands. In order to provide a spray air flow, the apparatus has a fan 1 from which a blow horn 2 leads to the wind chamber 4. The blow horn 25 expands evenly on its way from the fan to the wind chamber, substantially corresponding to the cross-section of the wind chamber.

At the mouth of the blowpipe 2 there is a flow equalizer 3 in which a straight hole-30 is used in the embodiment shown.

According to the invention, a grating structure consisting of transversely mounted plate strips 5 is mounted on the outlet side of the flow equalizer 3 in this basic apparatus known per se. The plate strips are located horizontally as well as vertically in the embodiment shown. The width of the plate strips is chosen so that the widest strips are arranged to pass over the central region of the flow equalizer 3, while the width of the strips only flanking the central region is already narrower and further narrows for the strips extending only in the edge regions.

With said dimensioning of the flow control strips 5, strips of different widths can pass over the central area of the flow equalizer 3, depending on the cross-sectional shape of the wind chamber. Usually, this shape is rectangular so that the wind chamber is wider in height. In this case, the vertical strips 5 in the central region are wider than those running horizontally.

In the embodiment shown, the grating structure formed by the plate strips 5 is mounted on the flow equalizer plate 3, but when examining the flows it has been found that this is not absolutely necessary. The flow discharged from the hole of the flow equalizer has been found to turn at the earliest at a distance of about 20 to 20-30 mm from the flow equalizer, so that the line structure can be extended at least to this distance from the surface of the flow equalizer 3. Depending on the flow conditions, the distance can in some cases be extended up to about 100 mm.

25 In practical installations, the desired distances of air currents of equal length can be achieved if the wind chamber-side edge of the plate strips forming the grating is extended in the central region of the flow equalizer to a distance of about 200 to 400 mm from the surface of the flow equalizer. Depending on the dimensions of the blowing equipment and the flow geometry, the distance requirement may be even greater, up to about 500 mm, but correspondingly lower.

The side dimension of the openings formed by the grating pattern is preferably in the range of about 50 to 200 mm, but may deviate from this value within the scope of the invention.

Claims (7)

A wind blower blower apparatus comprising a fan (1) and a fan extending into a wind chamber (4) extending blower horn (2) which extends to correspond to the cross section of the wind chamber, and a heel plate (3) or corresponding flow equalizer which equalizes the flow to the wind chamber, characterized in that one of the cross-sectional disc strips (5) consisting of grid structure is placed immediately after the flow equalizer (3) in the wind chamber (4), where width Mr. the greater the closer to the center region as it extends over the flow equalizer (3). 5 Blowing apparatus according to claim 1, characterized in that the distance to each disc strip (5) lies against the edge of the wind chamber from the point of contact of the fan (1) and the blowing horn (2) to the same as the length of the parallel wall of the blowing horn. Blowing apparatus according to claim 1 or 2, characterized in that the grating structure consisting of the disc strips (5) is mounted on the surface of the flow equalizer (3) facing the wind chamber. Blowing apparatus according to claim 1 or 2, characterized in that the grating structure consisting of disc strips (5) is mounted at a distance of approx. 1 - 100 mm, advantageously at a distance 1 - 30 mm from the flow equalizer (3) the surface facing the wind chamber (4). 5. A blowing apparatus according to any of the preceding claims, characterized in that the disc strips (5) are positioned horizontally and vertically. A blowing apparatus according to claim 5, characterized in that the vertical disc strips (5) are rotatable about their vertical axis. 30 7. A blowing apparatus according to any preceding claim, characterized in that the width of the grating openings of the disc strips is approx. 50 - 200 mm.