JPS61140414A - Air lift device for granular powder - Google Patents

Abstract

PURPOSE:To air transport high-density granular powder at low speed in a vertical air transport device for powder by blowing air in the base of a supply tank to cause an eddy to vertically transport the powder with a height- adjustable diffuser and a vertical transport pipe. CONSTITUTION:Granular powder P supplied from a powder supply pipe 12 into a supply tank 11 is accumulated at a mixing portion 11C. The mixing portion 11C has secondary air nozzles 14, 16 mounted on the base portion and the side wall portion, which have a designated blowoff deflecting angle with respect to the center, so that the secondary air 17 is jet out, thereby to let granular powder P flow in whirls to be mixed. Hereupon, the height of a diffuser 21 is controlled to blow the primary air from a primary air nozzle 13, thereby to blow the granular powder P in a vertical transport pipe 20, and the air and the granular powder P are separated from each other by a separator 25. The air is discharged 28, and the granular powder P is taken out 27. Thus, the powder can be transported with high density at a low speed.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a special pneumatic transportation device for powder and granular materials, and more particularly, it relates to a special pneumatic transportation device for powder and granular materials, and more specifically, to a powder and granular material that vertically transports the powder and granular materials by an air flow rising in a vertical transportation pipe. The present invention relates to an air lift device.

(Prior Art) There is a special device for transporting powder and granular materials that uses compressed air to transport vertically, and is generally called an air lift. The equipment arrangement of this airlift is similar to that of ordinary pressure-feeding air transport equipment, and is assembled in the order of an air compressor, a mixer (nozzle in the supply tank), and a vertical riser 9 separators. Powder in the riser is transported in suspension. Air lift differs from pneumatic transport using ordinary horizontal pipes in that the pipe line consists only of vertical rise pipes. Therefore, since the weight of the powder is supported by the drag force of the air, it can theoretically be transported if the air velocity is higher than the floating velocity of the powder. In addition, since air lifts are not limited by the mixing ratio of powder and compressed air, unlike pneumatic transport using horizontal pipes, transport at low speeds and high mixing ratios is possible.

Conventionally, the air lift device used for vertically transporting powder and granules as described above transports powder and granules from above a cylindrical powder supply tank l with a hollow lid via a powder supply path 2, as shown in FIG. body P
is supplied, and the powder P is gradually dropped and supplied to the mixing section 1a on the bottom side of the supply tank 1 whose diameter is reduced. A rising air nozzle 3 is provided at the center of the bottom plate of the supply tank 1 and has an outlet opening upward to blow out compressed air in a vertical direction. 1 air supply v4 is connected. The compressed air supplied to the first air supply pipe 4 and the rising air nozzle 3 is referred to as primary air air l. Further, an air blowing ring 5 is provided on the bottom surface of the supply tank l, and the air blowing ring 5 has numerous small holes 5a for air blowing formed in the circumferential wall of a hollow annular pipe. A second air supply pipe 6 that supplies compressed air from the outside is connected. still.

The compressed air supplied to the second air supply pipe 6 and the air blowing ring 5 is referred to as secondary air 'air2. Approximately at the center of the powder supply tank l, there is a vertical transport pipe 7 extending vertically.
is provided. The lower end of this vertical transport pipe 7 expands downward to form a diffuser 8, and this diffuser 8 faces the upper side of the rising air nozzle 3 and air blowing ring 5. Further, the upper part of the vertical transport pipe 7 extends vertically through approximately the center of the canopy part 1b of the supply tank 1,
At its upper end, a separator 9 is provided for separating the mixture of compressed air and granular material into granular material and exhaust air again.

As is clear from the above configuration, the powder P supplied from above the supply tank 1 is mixed in the mixing section 1a at the bottom of the supply tank 1.
The secondary air is blown out from the small hole 5a of the air blowing ring 5 without a fixed direction, and is stirred to form a mixture with compressed air. The mixing part 1a at the bottom of the supply tank 1 that stirs this mixture and the diffuser 8 serve as mixers for pneumatic transport.Next, the mixture stirred as described above is blown out from the rising air nozzle 3. It is carried by the primary air and reaches the separator 9 via the vertical transport pipe 7, where it is separated into exhaust gas and powder, completing the vertical transport.

In the above-mentioned air lift device, compressed air is supplied as primary air by the ascending air nozzle 3, and the powder is fed using the air resistance of the powder layer, so although it is a pressure feeding type, it is similar to a vacuum type nozzle. In addition to being able to mix under atmospheric pressure (arrow A in Figure 6), the separator 9 at the upper end is of a pressure-feeding type, making it easy to separate compressed air from powder and granules, and also allowing for continuous transportation. is advantageous.

By the way, in the above-mentioned air lift device, it is thought that the transport amount of the powder P moving up the vertical transport ee7 is determined by the amount of secondary air blown out from the air blowing ring 5, and this powder P and compressed air are The mixing ratio, which is the transport weight ratio per unit time, was thought to be related only to the amount of secondary air supplied and to have little to do with the blowing direction of the secondary air from the air blowing ring 5 (Reference `` "Pneumatic transportation of powder and granular materials"
(See 1984 edition, pages 284-280, especially page 288).

(Problems to be Solved by the Invention) However, the above-described conventional air lift device for powder and granular materials has the following problems.

First, it is said that the blowing direction of the secondary air blown out from the air blowing ring 5 and the mixing ratio have almost no relationship;
It is obvious that the agitation flow generated in the mixing section la at the bottom of the powder supply tank 1 depends on the directionality of the small holes 5a of the air blowing ring 5. This may reduce the amount of transport due to a decrease in the mixing ratio of the water, and may also cause so-called channeling (where air blows through partially) and bubbling (where air bubbles and blows up like boiling water). This poses a problem in that pneumatic transport may not be carried out properly due to the occurrence of air pollution.

In addition, the lower end side of the vertical transport pipe 7 is a diffuser 8 that expands downward, but if the mixing ratio differs depending on the specific gravity of the powder, particle size, supply amount of secondary air, etc. This leakage (arrow B in FIG. 6), which leaks upward from the supply tank 1 without being accommodated, changes the air resistance of the powder P layer and prevents the supply of the powder P to the mixing section 1a ( The arrow C) in FIG. 6 is not carried out well, resulting in a problem in that the mixed concentration of the powder and granules becomes low and smooth pneumatic transportation is not achieved.

SUMMARY OF THE INVENTION An object of the present invention is to provide an apparatus that improves the mixing ratio by generating a vortex in the mixing section at the bottom of the supply tank, thereby allowing low-speed, high-concentration pneumatic transport.

(Means for Solving the Problems) The features of the air lift device for powder and granular material according to the present invention for achieving the above object include a supply tank' that supplies the powder and granular material supplied from above to the bottom side; A primary air nozzle that opens upward at approximately the center of the bottom of the supply tank and blows out primary air in a vertical direction; a secondary air nozzle deflected from the central axis direction of the primary air nozzle, a vertical transport pipe extending vertically above the primary air nozzle, and a vertical transport pipe vertically adjustable at the lower end of the vertical transport pipe. and a separator connected to the upper end of the vertical transport pipe to separate the powder and compressed air.

(effect) The operation of the device constructed as above will be explained.

The powder and granules supplied from above the supply tank fall downward and are supplied to the bottom side of the tank, and are then blown out from a secondary air nozzle that is deflected in the direction of the central axis of the supply tank. The mixture is mixed by a vortex or a swirling flow caused by the secondary air, and this mixture is carried by the primary air blown up from the primary air nozzle to the separator via the vertical transport pipe, where it is mixed with the exhaust gas. The powder and granules are separated and transported by air.

In addition, powder and granules transported by air by air lift equipment and 2
The state of mixing with air differs depending on the type of powder, specific gravity, particle size, etc. Therefore, by adjusting the vertically movable diffuser, the height of the diffuser can be set at a position corresponding to the above-mentioned mixing state of the powder and the secondary air, and vertical transportation can be performed in accordance with the situation.

By acting as described above, the powder and granules are efficiently mixed with secondary air in a vortex or swirl flow, and the desired mixing ratio is achieved regardless of the type of powder or particle size, specific gravity, etc. mixed. Since the powder is then blown up in the vertical direction by the primary air, it is possible to prevent inefficiency in the amount of powder and granular material transported due to a decrease in the mixing ratio. Furthermore, it is possible to prevent the occurrence of so-called channeling, bubbling, etc., thereby providing an air lift device with good transport efficiency.

(Example) Hereinafter, an example of the air lift device for powder or granular material according to the present invention will be described with reference to the drawings.

Figures 1 to 5 are for explaining an embodiment of an air lift device for powder and granular materials. Figure 1 is a longitudinal sectional view showing the entire air lift device, and Figure 2 is an enlarged longitudinal sectional view of the main parts. The top view and Figure 3 are Figure 2 I, which also shows the blowing direction of secondary air.
-I cross-sectional view, FIG. 4 is an operation explanatory diagram showing the transportation process of powder and granular material, and FIG. 5 is a characteristic diagram showing the difference in mixing ratio between this embodiment and the conventional example.

In FIG. 1, an air lift device 1α has a powder supply pipe 12 connected above an open, substantially cylindrical supply tank 11, an air outlet opening upward in the center of a bottom surface 11a of the supply tank 11, and a compressor. A primary air nozzle 13 is provided that blows air vertically as primary air. This primary air nozzle 13 extends downward and has an expanded portion 13a whose lower end expands into a trumpet shape.
A primary air supply pipe 14 for supplying primary air air 1 from a compressor (not shown) faces.

As shown in FIGS. 2 and 3, the bottom surface 11a of the supply tank 11 is provided with a bottom secondary air nozzle +5 made of a convex cylindrical tube and surrounding the primary air nozzle 13. The outlet 15a of the bottom secondary air nozzle 15 is the third
As shown in the figure, the opening is deflected by a certain angle α from the direction of the central axis 0 of the supply tank 11. A side secondary air nozzle 1B is provided on the bottom side peripheral wall 11b of the supply tank 11.
The blowing direction of the blowing outlet 18a of this side secondary air nozzle 18 is directed toward the supply tank 1 as shown in FIG.
It is set to be deflected by a certain angle β from the direction of the central axis O of 1 and to be directed downward by a certain angle γ from the horizontal direction as shown in FIG.

The base side of the bottom and side secondary air nozzles 15.18 is surrounded by a flat cylindrical body with a central depression formed on the lower surface side of the bottom surface 11a of the supply tank 11 and on the outer peripheral side of the bottom side peripheral wall 1tb. It faces the next air supply path 17, and this
The next air supply path 17 is supplied with 2 air from a compressor (not shown).
Secondary air air2 is supplied via the secondary air supply pipe 1B.

In the compressed air blowing direction of the primary air nozzle 13, a first
A vertical transport pipe 20 is provided which extends vertically as shown. A diffuser 21 that expands downward in a trumpet shape is provided at the lower end of this vertical transport pipe 20.
The diffuser 21 is held by the tip of an arm 22 whose base end is fixed to the peripheral wall of the supply tank 11, and can be adjusted vertically by an adjusting screw 23.

A separator 25 is provided at the upper end of the vertical transport pipe 20, as shown in Figure tJII1. The separator 25 includes a powder separation section 2B mounted on the upper end of the vertical transport pipe 20, a delivery port 27 for supplying the powder separated in the powder separation section 2B to the next process, and It is constituted by an exhaust port 28 for discharging the compressed air mixed with the powder and granular material as exhaust gas.

The secondary air supply path 17 is formed by the cylindrical body 30 which is a flat cylindrical body with a concave center as described above, and at the bottom of this cylindrical body 30, a downwardly inclined chute 31 and a lid body 32 are provided as a supporting part. 33, and this support part 3
3 is fixed to a base 34. In addition, the supply tank 11
The lower end side of the diffuser 21 on the bottom side is a mixed part 11c.

The operation of the embodiment of the air lift device for powder and granular material having the above configuration will be described.

First, in FIG. 1, the powder P supplied to the supply tank 11 from the powder supply pipe 12 is supplied to the bottom side of the supply tank 11, and is connected between the lower end outer circumference of the diffuser 21 and the peripheral wall of the supply tank 11. The particles fall into the mixed portion 11c from between.

In this mixing part 11c, as shown in FIG.
The air is blown out from the air outlet 15a of No. 6, Ifla. As shown in FIG. 3, the blowing direction of this secondary air is deviated from the central axis 0 of the supply tank 11 by angles α and β, respectively, so the secondary air air2 in the mixer 11c becomes a vortex or a swirling flow. This means that the powder P is stirred.

Here, the operation of the diffuser 21 whose height from the bottom surface 11a can be adjusted by the adjusting screw portion 23 will be described using FIG. 2. The height d of the diffuser 21 has a different agitation ratio depending on the specific gravity, particle size, etc. of the powder or granules being air-transported, and the influence of the blowing up of the primary air differs depending on each powder or granule. Therefore, the diffuser 2 connected at the shortest point to one point on the periphery of the opening of the primary air nozzle 13
In a vertical plane including one point on the lower edge of 1, said 2
The relationship between the mixing state of the secondary air and the powder and the primary air is determined by the inclination angle θ of the straight line connecting the points.

In other words, the angle θ at which the granular material does not mix with the primary air is defined as the angle of repose.Since the angle of repose varies depending on the specific gravity of the granular material, particle size, etc., the angle θ is adjusted so that the desired angle of repose is obtained for each granular material. All you have to do is set it.

Therefore, the height d of the lower end of the diffuser 21 is determined by the following formula: jan-1d/or It is only necessary to set the height d so that it becomes θ.
3, a desired angle of repose θ can be obtained.

Adjust the diffuser 21 as described above, and
The secondary air air 2 is thoroughly stirred and then vertically transported via the vertical transport pipe 20 by the primary air air 1 blown from the primary air nozzle 13, and separated into the powder P and the exhaust air by the separator 25. and the outlet port 27. It is sent out and discharged from the exhaust port 28.

Pneumatic transport of powder and granules is carried out continuously, but when transport is stopped, the supply of primary air a'irl is usually stopped after stopping the supply of secondary air a'ir'2. Therefore, the powder P does not accumulate in the vertical transport pipe 20. However, if the supply of primary air is stopped due to a malfunction of the compressor, etc., the primary air static pressure will be 2000+* Since mH is below 0, retransport is impossible. Therefore, in order to restart the air lift device 10 quickly, the lid 32 of the chute 31 is removed and the powder is scraped out from the opening of the chute 31.

The unique effects of the above-described embodiment of the air lift device for powder and granular materials will be explained.

First, in the above embodiment, the side secondary air nozzle 18 is also provided on the peripheral wall 11b of the mixing section 11c of the supply tank 11, and the mounting direction of this side secondary air nozzle 1B is deflected by an angle β from the central axis O direction. In addition, since it is directed downward by the angle γ, the swirling flow of the secondary air air2 and the upward flow of the primary air air1 within the mixer 11c cause the powder P to contact the lower end of the diffuser 21 and the peripheral wall of the supply tank 11. This has the unique effect of preventing air from leaking and flowing backwards from between the holes.

Furthermore, since the diffuser 21 extends close to the peripheral wall of the supply tank 11, this configuration also prevents the feedback of the powder P as described above.

Furthermore, in this embodiment, a mixing section ILc is formed, which is composed of an expanded diffuser 21 as a mixing device and a tank bottom.
In this mixing part 11c, the powder P and the secondary air air2 are sufficiently stirred by the vortex or swirl flow, so the powder and granule can be mixed with a smaller amount of secondary air than in the conventional air lift device shown in FIG. It was possible to achieve high effectiveness in stirring.

Incidentally, as shown in Fig. 5, the correlation between the mixing ratio and the amount of secondary air in this example is as shown by the solid line m, which is due to the agitation of powder and granular material according to the conventional example shown in Fig. 6. It has been demonstrated that a high mixing ratio is achieved with a small amount of secondary air compared to the dotted line n, which is the measured value of .

In the above embodiment, the vertical adjustment mechanism of the diffuser 21 was explained as being performed by the adjustment screw part 23, but the present invention is not limited to this, and the adjustment may be performed using an electric motor and a rack and pinion gear. The vertical movement may be adjusted by a cylinder and a cylinder rod.

Further, although the above embodiment has been described as having both the bottom secondary air nozzle 15 and the side secondary air nozzle 1B, the present invention is not limited to this, and the secondary air flow is swirled or swirled. As long as the stirring performance can be improved by imparting regularity like flow, either one can be used, or nozzles with separate configurations may be used.

(Effects of the Invention) As described above in detail, the powder air lift device according to the present invention provides the following effects.

Since the secondary air nozzle is deflected at a certain angle from the center of the supply tank where the primary air blows up, it is possible to stir the powder and granules with a vortex or swirling flow when mixing the secondary air. An airlift for powder and granular materials that can increase the mixing ratio by reducing the amount of secondary air relative to the primary air, and can transport highly concentrated powder and granular materials even when primary air is supplied at a low speed, resulting in high transportation efficiency. equipment can be provided.

In addition, a diffuser that can be moved up and down is installed at the bottom end of the vertical transport pipe, so that it can be used to transport powder or granules with different mixing ratios depending on the specific gravity of the powder or grain size. There is no risk of the particles being blown into the vertical transport pipe, so-called channel rings and bubbling can be prevented, and smooth pneumatic transport of the powder and granular materials can be realized.

[Brief explanation of the drawing]

1 to 5 are for explaining an embodiment of the air lift device for powder and granular materials according to the present invention. FIG. 1 is a vertical sectional view showing the entire air lift device, and FIG. FIG. 3 is a cross-sectional view taken along the line I-I in FIG. 2, which also shows the blowing direction of secondary air. FIG. is a characteristic diagram comparing the difference in mixing ratio between this example and a conventional example. Moreover, FIG. 6 is a longitudinal cross-sectional view of the entire device showing an example of a conventional air lift device for powder and granular materials. 11... Supply tank, lla... Bottom, 13...
Primary air nozzle, 14... (first) air supply pipe, 15
... Bottom secondary air nozzle, 16... Side secondary air nozzle, 17... Secondary air supply path, 18... (second)
Air supply pipe, 20... Vertical transport pipe, 21... Diffuser, 23... Adjustment screw part, 25... Separator, P
...powder, air l...primary air, air2.
...Secondary air. Patent Applicant: Toyota Motor Corporation (and 1 other person) Figure 1 Bird 2 cause Figure 4

Claims (1)

[Claims] (1) A supply tank that supplies powder and granules supplied from above to the bottom, and a supply tank that is provided with an upward opening at approximately the center of the bottom of the supply tank and that supplies compressed air supplied from a first air supply pipe to the primary tank. A primary air nozzle that blows air vertically, and a second air nozzle that opens into the tank at the bottom side of the supply tank.
The air outlet is deflected so as to blow out the compressed air supplied from the air supply pipe as secondary air, and deflect the blowing direction of the secondary air at a certain angle from the central axis direction of the supply tank. a secondary air nozzle; a vertical transport pipe extending vertically above the primary air nozzle;
A diffuser is provided at the lower end of the vertical transport pipe and expands downward and is movable in the vertical direction. The diffuser is connected to the upper end of the vertical transport pipe and is connected to the upper end of the vertical transport pipe to transport the powder and compressed air that have been pumped through the vertical transport pipe. An air lift device for powder and granular material, characterized in that it is configured by a separator for separating powder and granular materials.