Blowing device

Abstract

The blowing device (1) is used for providing pressurized air to the surface of an object. The blowing device comprises a housing (3) having a pressurized gaseous fluid inlet (17), the housing having an outlet surface (9) comprising a plurality of primary exhaust passages (19) and a plurality of secondary exhaust passages (21), where the secondary exhaust passages are angled away from the primary exhaust passages at an angle [beta], therefore, uniform pressure distribution is obtained on the surface of the object.

Description

Technical Field

[0001] The present invention relates to blowing devices for providing pressurized air to an object surface, such as air knives and air manifolds. Background Art

[0002] For many years, blowing devices commonly known as air knives, air manifolds, and air (nozzle) manifolds have been used in many industrial and manufacturing processes to deliver pressurized air to the surface of stationary or moving objects to purge, i.e., remove, liquid or debris from these object surfaces, or to cool or heat these object surfaces.

[0003] A typical air knife consists of a manifold or air chamber having a long and narrow air slot, which can be continuous or segmented to form a plurality of small openings through which pressurized air can be discharged along the length of the slot. The slot is intended to provide a continuous air flow or jet along the length of the slot. The air knife is typically placed in a position close to the component to be purged, and any interruption in the continuous air flow can be detrimental to the purging effect.

[0004] An air nozzle or air manifold consists of a manifold or air chamber with a plurality of air outlet nozzles having circular or elongated openings placed at different intervals along the length of the manifold. The air nozzle / manifold does not provide a continuous air flow along the length of the air nozzle / manifold like an air knife does. Instead, the orifice of each outlet nozzle typically delivers a much larger air flow in a concentrated area in the form of a high-speed air flow from each outlet nozzle. Problems can occur when two adjacent air flows impinge on the surface at the same location but from different angles, because the resulting combined air flow may form a "blind spot" that lacks the desired cleaning effect and is unable to remove liquid or debris.

[0005] For compressed air blowing devices, important characteristics are the noise level, consumption, power, and blowing pattern. These four parameters depend on the pressure in the blowing device and are typically specified at different pressures.

[0006] In many air applications today, it is required that the cross-sectional area of the jet be rectangular, where the width of the air flow should be maximized and the height should be minimized. Preferably, the noise level and air consumption should also be minimized. One way to achieve this is to use a number of smaller outlet nozzles instead of using a larger outlet nozzle. The size and center-to-center distance of the outlet nozzles are carefully calculated to minimize the sound level at a given pressure. The outlet nozzles can be placed in different patterns to obtain a specified blowing pattern. The cross-sectional area of the outlet openings in the nozzles and the distance between them together determine the cross-sectional area of the nozzle.

[0007] To determine the blowing pattern, the relative pressure generated on a flat surface by a manifold facing the surface at 90° can be measured.

[0008] In the case of the pattern design of a given outlet channel, if it is desired to increase the relative pressure across the width of the blowing pattern, this can only be achieved by adjusting the input pressure.

[0009] The disadvantage of increasing the pressure is that it tends to cause a disproportionately high pressure increase at the center of the air jet (which is rarely required for this type of nozzle), rather than a proportional increase across the entire width of the blowing pattern. This means that in practice, you use an unnecessary amount of energy to increase the relative pressure across the entire surface covered by the air flow. Therefore, there is a need for a blowing device that can provide more even coverage on the surface for a given pressure and a given cross-sectional area of the nozzle of the device. Summary of the Invention

[0010] An object of the present invention is to overcome or at least minimize the above problems by means of a blowing device having the features of claim 1. Such a blowing device is characterized in that it has a set of at least two adjacent central exhaust channels that direct pressurized gaseous fluid from the blowing device at a first angle, wherein the set of central exhaust channels is surrounded on each side by at least one exhaust channel oriented at an angle away from the nearest central exhaust channel. Due to the presence of at least two adjacent central exhaust channels pointing in the same direction and the presence of additional exhaust channels pointing away from that direction, the jet formed by the mixed gas of the pressurized gas exiting these exhaust channels unexpectedly exhibits a smaller central peak pressure than a blowing device having a single central exhaust channel pointing in a first direction and arranged between additional exhaust channels oriented at an angle away from the central exhaust channel. Description of the Drawings

[0011] Figure 1a ) to Figure 1c ) schematically shows a side view, a plan view, and an end view of a first embodiment of a blowing device according to the present invention.

[0012] Figure 2a ) to Figure 2c ) schematically shows a side view, a plan view, and an end view of a first embodiment of a blowing device according to the present invention.

[0013] Figure 3 Shows examples of relative pressures measured at locations across the surface using different angles of the exhaust channels. Detailed Description

[0014] Figure 1a ) - Figure 1c)(a) A side view, a plan view, and an end view of a blowing device 1 according to a first embodiment of the present invention are schematically shown and not to scale. The blowing device 1 includes a housing 3 having an outer wall 5, and the housing 3 encloses a chamber 7. The housing is in the form of a box, which is shown as being generally rectangular in this example, but may be any other suitable shape, and the box has an outlet surface 9 that faces an article onto which air is blown as shown by arrow 11. Preferably, the outlet surface 9 is flat and elongated, having a main central line 13 extending in a first direction X and a secondary central line 15 extending perpendicular to the main central line in a direction Y. The outer wall 5 has a pressurized gas supply inlet 17 that is adapted to be connected to a pressurized gas supply source (not shown). The outlet surface 9 is provided with a plurality of primary exhaust channels 19 and a plurality of secondary exhaust channels 21, and both the primary exhaust channels 19 and the secondary exhaust channels 21 extend from the chamber 7 through the outer wall 5 and open through openings 22 on the outlet surface 9. The primary and secondary exhaust channels are shown as being arranged in a straight line along the main central line of the outlet surface so as to give symmetry to this embodiment of the present invention, but they may be arranged in any other way, such as parallel to the main central line or at an angle to the central line. The plurality of primary exhaust channels form a set of primary exhaust channels 23, and the set of primary exhaust channels 23 includes at least two adjacent primary exhaust channels 19 that are configured to direct a pressurized gaseous fluid at a first angle α to the outlet surface. Preferably, this angle is perpendicular to the outlet surface. If the blowing device is intended to provide an air jet that is substantially symmetric along the main central line, then the center of the set of primary exhaust channels may coincide with the midpoint of the main central line as shown. If the blowing device is intended to produce an asymmetric air flow, then the center of the primary exhaust channels may be placed on one side of the midpoint of the main central line. The set of primary exhaust channels forms a line, preferably a straight line, and at each end in the direction of the main central line there follows at least one secondary exhaust channel 21 that is directed at an angle β away from the angle α in the direction along the main central line. As Figure 1aAs shown in ), the central group 23 of the two primary exhaust channels 19 has three secondary exhaust channels 21 disposed on its left side that direct the pressurized gas to the left at an angle β and three secondary exhaust channels 21 disposed on its right side that direct the pressurized gas to the right at an angle β. In this embodiment of the present invention, there are two primary exhaust channels in this group of primary exhaust channels, and a total of six secondary exhaust channels configured in groups of three are present on either side of this group of primary exhaust channels. However, there may be more than two primary exhaust channels in this group of primary exhaust channels, and the number of secondary exhaust channels on each side of this group of primary exhaust channels may be any number equal to or greater than 1. The center-to-center distance between adjacent exhaust channels may be equal for all exhaust channels, or may be different for some adjacent exhaust channels. For example, the center-to-center distance may be greater for adjacent exhaust channels that are further away from the primary exhaust channels compared to adjacent exhaust channels near the primary exhaust channels, or vice versa.

[0015] For each exhaust channel, the cross-sectional area of the exhaust channel may be the same, or they may be different.

[0016] Figure 2a )- Figure 2c ) schematically and not to scale shows a side view, a plan view, and an end view of the blowing device 1 according to a second embodiment of the present invention, wherein Figure 1a )- Figure 1cThe same reference numerals used in ) are used for like elements in these figures. Thus, the blowing device 1 includes a housing 3 having an outer wall 5, and the housing 3 encloses a chamber 7. The housing is in the form of a box, which is shown as being generally rectangular in this example, but may be any other suitable shape, and the box has an outlet surface 9 that faces an article onto which air is blown as shown by arrow 11. Preferably, the outlet surface 9 is flat and elongated, having a main central line 13 extending in a first direction X and a secondary central line 15 extending perpendicular to the main central line in a direction Y. The outer wall 5 has a pressurized gas supply inlet 17 that is adapted to be connected to a pressurized gas supply source (not shown). The outlet surface 9 is provided with a plurality of primary exhaust channels 19 and a plurality of secondary exhaust channels 21, both the primary exhaust channels 19 and the secondary exhaust channels 21 extending from the chamber 7 through the outer wall 5 and opening through outlets 22 on the outlet surface 9. The primary and secondary exhaust channels are shown configured in a straight line along the main central line of the outlet surface so as to give symmetry to this embodiment of the invention, but they may be configured in any other way, such as parallel to the said main central line or at an angle to the central line. The plurality of primary exhaust channels form a set of primary exhaust channels 23, and the set of primary exhaust channels 23 includes at least two adjacent primary exhaust channels 19 configured to direct pressurized gaseous fluid at a first angle α to the outlet surface. This angle may be perpendicular to the outlet surface or at an angle less than or equal to 10°. If the blowing device is intended to provide an air jet that is substantially symmetric along the main central line, then the center of the set of primary exhaust channels may coincide with the midpoint of the main central line as shown. If the blowing device is intended to produce an asymmetric air flow, then the center of the primary exhaust channels may be placed on one side of the midpoint of the main central line. The set of primary exhaust channels preferably forms a straight line, with at least one secondary exhaust channel 21 following at each end in the direction of the main central line, and the secondary exhaust channel 21 pointing at an angle β away from the angle α in the direction along the main central line. As Figure 2b shown in ), the central set 23 includes two primary exhaust channels 19, and just outside the set of primary exhaust channels, on each side thereof, a pair of secondary exhaust channels 25 have been positioned, the secondary exhaust channels being configured parallel to the secondary central line 15. Even further outside each set of two secondary exhaust channels, a single secondary exhaust channel is configured on the main central line. This single secondary exhaust channel is followed by another pair of secondary exhaust channels parallel to the secondary central line 15.

[0017] Figure 3The experimental results of a blowing device are shown. The blowing device includes a row of exhaust channels arranged in a straight line. The blowing device includes two central primary exhaust channels that point straight at a flat pressure measurement surface. A plurality of secondary exhaust channels of the same cross-sectional area are positioned on either side of the pair of primary exhaust channels. The inlet pressure is 0.5 MPa, the distance to the pressure measurement surface is 200 mm, and the surface area is 290 mm × 310 mm. The surface of the blowing device facing the pressure measurement surface is 43 mm × 7 mm. The surface of the blowing device facing the pressure measurement surface has two central primary exhaust channels arranged at a center-to-center spacing of 2.7 mm and 14 secondary exhaust channels (seven on either side of the central primary exhaust channels). All the exhaust channels are circular with an opening diameter (D) of 0.9 mm. Using two central primary exhaust channels minimizes turbulence and thus minimizes the noise level compared to using a single larger exhaust piece having the same cross-sectional area as the sum of two smaller exhaust pieces. Additionally, when blowing air onto a flat surface, using a single central primary exhaust channel may result in a central pressure drop.

[0018] A series of experiments were conducted using the same inlet pressure but with the secondary channels angled at different angles away from the first exhaust channel. The angles tested were 0°, 1.5°, 2.5°, 4°, and 6°. As Figure 3 can be seen, increasing the tilt angle of the secondary exhaust channels results in a desirable lower but wider distinct peak, which gives good coverage of the surface without an overly high peak pressure at the center that would only waste energy. Surprisingly, at an angle of approximately 6°, the peak not only widens but also forms a plateau, giving an almost constant pressure over a wider position range. This is desirable as it gives a good cleaning or cooling effect over a wide area without the need to increase the inlet pressure.

[0019] In all embodiments of the present invention, the secondary exhaust channels can be tilted at the same angle β away from the nearest adjacent primary exhaust channel. Preferably, in the direction away from the nearest primary exhaust channel, the angle β is greater than or equal to 1 degree and less than or equal to 10 degrees, more preferably, the angle β is greater than or equal to 2 degrees and less than or equal to 9 degrees, even more preferably, the angle β is greater than or equal to 3 degrees and less than or equal to 8 degrees, still more preferably, the angle β is greater than or equal to 4 degrees and less than or equal to 7.5 degrees, and most preferably, the angle β is greater than or equal to 5 degrees and less than or equal to 7 degrees.

[0020] It is also conceivable that the angle β varies as the distance of the secondary exhaust passage from the closest primary exhaust passage increases. For example, the secondary exhaust passage closest to the primary exhaust passage may be inclined at an angle β away from the primary exhaust passage, the next secondary exhaust passage may be inclined at an angle β + x degrees, the next secondary exhaust passage may be inclined at β + y degrees, and the subsequent secondary exhaust passages may be inclined at an angle of β + z degrees, etc., where z > y > x.

[0021] Preferably, the maximum diameter or width (D) of the opening (22) of any exhaust passage is equal to or less than 1.0 mm and greater than or equal to 0.5 mm, and more preferably, less than or equal to 0.9 mm and greater than or equal to 0.6 mm. Preferably, all the primary exhaust openings have substantially the same cross-sectional area as each other, and / or all the secondary exhaust openings have substantially the same cross-sectional area as each other, or the openings of all the exhaust passages have substantially the same cross-sectional area.

[0022] Preferably, the minimum center-to-center distance between adjacent exhaust passages is equal to or greater than three times and less than or equal to five times the maximum diameter or width (D) of the widest opening of the adjacent exhaust passages.

Claims

1. A blowing device (1) for supplying pressurized air to an object surface, comprising: A housing (3) having a pressurized gaseous fluid inlet (17) and a plurality of primary exhaust channels (19) and a plurality of secondary exhaust channels (21), the plurality of primary exhaust channels and the plurality of secondary exhaust channels leading to and opening on an outlet surface (9) of the housing, wherein the exhaust channels together discharge the fluid from the housing (3), the blowing device (1) being characterized in that the plurality of exhaust channels include a set (23) of at least two adjacent primary exhaust channels (19) arranged in a line and guiding the pressurized gaseous fluid at a first angle α with respect to the outlet surface (9), wherein at each end of the line, the set (23) of adjacent primary exhaust channels is followed by at least one secondary exhaust channel (21), the secondary exhaust channel being oriented at an angle β away from the closest primary exhaust channel.

2. The blowing device according to claim 1, characterized in that, The at least one secondary exhaust channel (21) is arranged at an angle β away from the closest primary exhaust channel (19) that is greater than or equal to 1 degree and less than or equal to 10 degrees.

3. The blowing device according to claim 1, wherein The angle β is greater than or equal to 2 degrees and less than or equal to 9 degrees.

4. The air blowing device according to claim 3, characterized in that, Preferably, the angle β is greater than or equal to 3 degrees and less than or equal to 8 degrees, more preferably, the angle β is greater than or equal to 4 degrees and less than or equal to 7.5 degrees, and most preferably, the angle β is greater than or equal to 5 degrees and less than or equal to 7 degrees.

5. The blowing device according to any one of the preceding claims, characterized in that, The number of primary exhaust channels (19) in the set of at least two primary exhaust channels is equal to or greater than two and less than or equal to six.

6. The blowing device according to any one of the preceding claims, characterized in that, The openings (22) of all the primary exhaust channels (19) have substantially the same cross-sectional area with respect to each other, and / or the openings (22) of all the secondary exhaust channels (21) have substantially the same cross-sectional area with respect to each other, or the openings (22) of all the exhaust channels (19, 21) have substantially the same cross-sectional area.

7. The blowing device according to any one of the preceding claims, characterized in that, The maximum diameter or width (D) of the opening (22) of any exhaust channel (19, 21) is equal to or less than 1.0 mm and greater than or equal to 0.5 m.

8. The blowing device according to any one of the preceding claims, characterized in that, The maximum diameter or width (D) of the opening (22) of any exhaust channel (19, 21) is equal to or less than 0.9 mm and greater than or equal to 0.6 mm.

9. The blowing device according to any one of the preceding claims, characterized in that, The center-to-center distance between adjacent exhaust channels (19, 21) is substantially the same.

10. The air blowing device according to any one of the preceding claims, characterized in that, The center-to-center distance between adjacent exhaust channels (19, 21) is equal to or greater than three times and less than or equal to five times the maximum diameter or width (D) of the widest opening (22) of the adjacent exhaust channels (19, 21).

11. The blowing device according to any one of the preceding claims, characterized in that, The exhaust channels (19, 21) are arranged in a straight line.

12. The blowing device according to any one of the preceding claims, characterized in that, The exhaust channels (19, 21) are arranged in a first set including a plurality of exhaust channels (19, 21) on a first line, wherein at least one additional set of at least two exhaust channels (19, 21) is arranged on a second line intersecting the first line.

13. The blowing device according to claim 12, characterized in that, Each of the additional groups of exhaust passages includes two exhaust passages (19, 21) and is symmetrically placed between a pair of the exhaust passages (19, 21) of the first group of exhaust ducts and is symmetric about the first line.

14. The blowing device according to any one of the preceding claims, characterized in that, The first angle α is approximately 90°.

Images