JPH0747120B2 - Deaeration device for powder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention increases the bulk density of powder and granules and reduces the volume of the powder and granules to facilitate handling such as bagging and transportation. It is about.

[Conventional technology]

As a conventional deaeration device for powder and granules, for example, as shown in FIG. 5, the powder and granule input port 10 is provided at one end and the discharge port 11 is provided at the other end.
A perforated cylindrical portion 1a is formed in an intermediate portion of a cylindrical main body 1 provided with, and an outer cylinder 2 having an intake / exhaust pipe 8 and a compressed air pipe 9 is concentrically provided outside the perforated cylindrical portion 1a with a gap. There is known a device which is provided with a vacuum evacuation chamber so that the air in the powder and granules can be sucked and discharged from the suction and exhaust pipe 8 while being transferred by the screw conveyor 4 in the cylindrical main body 1.

As the perforated cylindrical portion 1a, a filter in which a cloth filter cloth 13 is sandwiched between perforated metal plates 14 'and 14 "as shown in FIGS. 6 and 7 is used.

[Problems to be Solved by the Invention]

In conventional deaerators such as this, typically -600 mmHg
Often operates between ~ 700mmHg. Therefore, the sixth
As shown in FIGS. 7 and 7, the filter cloth 13 is attached to the porous metal plate 1
In the configuration of the degassing part by the filter sandwiched by 4 ', 14 ",
The fibers of the cloth filter cloth 13 in the perforated cylindrical portion were liable to be stretched and cut, and the powder and granules leaked into the vacuum pump side, often resulting in operation failure. So metal plates 14 ', 14 "
The filter cloth 12 was protected by reducing the opening ratio of the holes of the above, and the insufficient strength of the cloth fiber was compensated for. However, for example, even if the porosity of the metal plates 14 ', 14 "is about 40%, the life of the filter is about one week. If the porosity is further reduced, the filtration area of the filter decreases and As a result, the performance as an air-conditioning device is remarkably reduced, and it is difficult to assemble the holes of the inner and outer metal plates with each other through the filter cloth, and it is difficult to replace the filter cloth. It took a long time.

Further, such a deaerator has a clearance of several mm between the screw flight and the filter, so that a cake layer of powder and granules is formed there, and the powder and granules are transported through the cake layer. It degass the air. Therefore, in the case of a granular material having a high filtration resistance in the cake layer,
It is regularly necessary to remove the cake layer by backwashing the filter. In this case, compressed air of ^{2 to 3} kg / cm ² or more is usually used for backwashing, but backwashing may be performed several times per hour. Therefore, in the conventional cloth filter, breakage due to backwashing has a great influence, powder particles easily leak, and the frequency of filter replacement increases. Further, there is a drawback that it is not suitable for use in the fine field where foreign substances such as foods and pharmaceuticals are particularly unfavorable, because the fibers fall off during backwashing.

An object of the present invention is to solve the above-mentioned conventional problems in the deaerator, prevent leakage of the powder or granular material to the vacuum pump side, and increase the filtration efficiency in the porous cylindrical portion,
It is an object of the present invention to provide a device that can be easily backwashed, the number of uses of the filter body can be remarkably extended, and an excellent deaeration effect can be achieved.

[Means for Solving the Problems]

That is, according to the present invention, a substantially cylindrical intermediate body having a granular material supply port at one end and a discharge port at the other end is made into a perforated cylindrical portion, and an outer cylinder having an intake / exhaust pipe is provided outside the perforated cylindrical portion. A vacuum exhaust chamber is formed, and in the degassing device of the powder and granules, in which a screw conveyor for transferring the powder and granules is provided in the cylindrical main body, a sintered body of fine metal fibers is added to the porous cylindrical portion. It is characterized in that it is used to solve the above problems.

As shown in FIGS. 2 and 3, the perforated cylindrical portion is usually formed inside a filter having a laminated structure by sandwiching both sides of a layer 12 of a sintered metal fiber body with wire nets 15 and 15 '. A plate 14 made of a metal plate (hereinafter referred to as a metal protection plate) is closely attached to form a cylindrical shape.

The metal fiber sinter 12 is made of a fine wire having a wire diameter of 15 .mu.m or less, preferably 1 to 10 .mu.m. Such a material has an excellent cutting strength, is capable of microfiltration, and can withstand long-term use. In general, the metal fiber structure (layer) 12 as described above may be vacuum-sintered and compressed, and the wire nets 15 and 15 'may be provided on both surfaces thereof, or may be integrally sintered with the wire net. The layer 12 of the metal fiber sintered body may be a single layer, or may be a laminate of a plurality of layers that are appropriately combined in a dense and fine manner as needed. The porosity of such a layer is usually preferably selected from the range of 65 to 82%. Examples of the metal include stainless steel, nickel, Inconel, Carpenter, Hastelloy, and other corrosion-resistant and heat-resistant metals and alloys. Examples of the wire nets 15 and 15 'to be applied to both surfaces include a plain weave structure of 20 to 40 mesh, but are not limited thereto. The perforated cylindrical metal protective plate provided inside the filter body having such a configuration serves to protect and retain the shape of the metal fiber sintered body, and usually has a plate thickness of 2 to 3 mm and an aperture ratio. 60-70% punch metal is used. Perforated cylindrical part (sintered metal)
In a small device having an inner diameter of 100 mm or less, for example, it is preferable to use a wire net having a wire diameter of 0.4 mm or more and integrally sinter with the metal fiber layer.

〔Example〕

 Hereinafter, specific embodiments will be illustrated and described in the drawings.

FIG. 1 is a partially cutaway front view of the entire device of the present invention, and FIG.
It is a -I line sectional enlarged view. 1 is a cylindrical main body, 1a is a perforated cylindrical portion, 2 is an outer cylinder provided on the outside thereof, and side plates 3 thereof,
A vacuum exhaust chamber 2a is formed by closing both ends with 3 ',
The outer cylinder 2 is provided with an intake / exhaust pipe 8 and compressed air pipes 9, 9 '. 4 is a screw conveyer for powder and granular material transfer,
In this example, the shaft diameter of the screw shaft gradually increases from the upstream side to the downstream side. 10 is a powder / granule supply port, 11 is a degassed powder / granule discharge port, and 16 is an inspection window.

Note that FIG. 3 is an enlarged cross-sectional view illustrating the configuration of the perforated cylindrical portion 1a, in which a metal protective plate 14 is provided with a metal fiber layer 12 and a wire mesh.
A sintered body of 15, 15 'is welded and fixed, and a porous cylindrical portion 1a is formed with the metal protective plate 14 inside.

In this apparatus, the powder or granular material supplied from the powder or granular material supply port 10 into the main body 1 is transferred to the discharge port 11 by the screw conveyor 4 and is passed through the perforated cylindrical portion 1a. Air is sucked and degassed from the suction / exhaust pipe 8 by the vacuum pump through the vacuum exhaust chamber 2a, and the bulk density is gradually increased to the exhaust port.
Emitted from 11.

At this time, the granular material is prevented by the filter mainly composed of the metal fiber sintered body 12 of the porous cylindrical portion 1a and does not leak into the vacuum exhaust chamber 2a or the suction / exhaust pipe 8 side. The backwashing of the filter is normally performed by blowing air from the compressed air pipes 9 and 9 ', but there is no possibility of stretching or cutting due to the high pressure air.

〔The invention's effect〕

Next, the operation and effect will be clarified by showing experimental examples and results of deaeration of powdery particles by the device of the present invention.

Incidentally, in the comparative example, the porous cylindrical portion 1a has a metal plate 14 ', 1
This is due to the conventional device formed from 4 ″ and the cloth filter cloth 13.

In each case, a powder having a bulk density of 0.035 g / cc in a packed state was used as an object to be treated.

Further, the perforated cylindrical portion 1a in the device of the present invention has a wire diameter of about 10
Porosity consisting of sintered web of μm stainless steel fiber
A filter with about 20 mesh wire mesh on both sides of 65% layer 12 was used.

The experimental results were as shown in FIG.

In the figure, the degassing index indicates the product of the vacuum pressure in the vacuum exhaust chamber and the processing time. The processing time is the time until the charged raw material passes through the porous portion 1a, and is set by changing the rotation speed of the screw. Generally, the bulk density of a powder or granular material is affected by physical properties, vacuum pressure, and processing time. The results of this experiment were performed by keeping the vacuum pressure constant at -700 mmHg and changing the treatment time. From this result, for example, a degassing index of 1400 (-cm x sec) means a treatment time of 20 (sec). To compare the performance at this time, in the conventional device, the bulk density after treatment was 0.041 g. Although it was / cc, in the device of the present invention, 0.056
You can see that it was processed to g / cc. Furthermore, in order to obtain the same bulk density as that of the device of the present invention, a processing time of about twice is required.
As described above, the apparatus of the present invention can process a high bulk density in a short processing time.

Further, since the deaerator transports the powder or granular material on the screw conveyor, it is known that the transport efficiency decreases as the screw rotation speed increases. In the driving result,
The number of revolutions was 0.9 at 14 rpm and 0.65 at 30 rpm, although it depends on the type of powder.

Next, Table 1 shows the result of comparison between the throughput and the life of the cylindrical porous portion. As for the processing capacity, powder with a bulk density of 0.036 g / cc is used.
This is a comparison when processing to 0.06 g / cc.
It can be seen that the conventional device has a processing capacity of 1.7 m ³ / hr, while the device of the present invention has a processing capacity of 2.6 m ³ / hr, which is about 1.5 times the processing capacity.

Furthermore, since the life is several tens of times that of conventional products,
The replacement work of the filter is rarely done, and the maintenance is extremely easy.

By applying a sintered body of metal fibers to the porous cylindrical portion in this way, it becomes possible to perform precision filtration, not only the leakage of powder and granules is eliminated, but also surface filtration of powder and granules is possible,
The effect of the present invention is extremely great because the filter is not clogged and the excellent degassing effect can be maintained for a long time.

[Brief description of drawings]

FIG. 1 is a front view showing a partially cutaway embodiment of the present invention,
2 is an enlarged cross-sectional view taken along the line I-I, FIG. 3 is a cross-sectional view showing an example of the structure of the perforated cylindrical portion, FIG. 4 is a graph showing the results of degassing experiments, and FIG. 5 is conventional degassing. Partially cutaway front view of the device,
FIG. 6 is an enlarged cross-sectional view taken along the line I-I, and FIG. 7 is an enlarged cross-sectional view showing the structure of the porous cylindrical portion of the conventional device. DESCRIPTION OF SYMBOLS 1 ... Cylindrical main body, 1a ... Perforated cylindrical part, 2 ... Outer cylinder, 8,8 '...
Intake / exhaust pipe, 4 ... Screw conveyor, 12 ... Metal fiber sintered body, 15,15 '... Mesh, 14 ... Metal protective plate

Claims (2)

[Claims] 1. A perforated cylindrical body having a powdery and granular material supply port at one end and a discharge port at the other end, and an approximately middle portion of the cylindrical main body is provided with an outer cylinder having an intake / exhaust pipe on the outer side thereof. In a degassing apparatus for powder and granular materials, which forms a vacuum exhaust chamber by inserting a screw conveyor for transferring powder and granular materials in the cylindrical main body, a sintered body of fine metal fibers in the porous cylindrical portion. A deaeration device for powder and granules, characterized by using. 2. The deaeration device for powder and granules according to claim 1, which is formed by sintering metal fibers having a wire diameter of 15 μm or less.