GB2149374A

GB2149374A - Pneumatic conveyor channel for the transport of granular and/or powered materials

Info

Publication number: GB2149374A
Application number: GB08425242A
Authority: GB
Inventors: Gyorgy Vigyazo; Laszlo Angyan; Miklos Tokoli; Ferenc Stvrteczky
Original assignee: Eroemue Es Halozattervezoe
Current assignee: Eroemue Es Halozattervezoe
Priority date: 1983-10-06
Filing date: 1984-10-05
Publication date: 1985-06-12
Also published as: DE3436357A1; IT8423043A1; NL8500210A; DE3436357C2; FR2553072A1; HU188497B; HUT34926A; FR2553072B1; ATA305584A; AT389687B; GB2149374B; IT8423043A0; IT1176889B; GB8425242D0

Abstract

Pneumatic conveyor channel for the transport of granular and/or powdered materials comprises a material channel (6), in which material is fluidised by gas from a chamber 7 fed by a pipe 5 and separated from the channel by a wall 2, gas exiting from the channel 6 via a wall 1 into an outlet chamber 8. <IMAGE>

Description

SPECIFICATION Pneumatic conveyor channel for the transport of granular and/or powdered materials The invention relates to pneumatic conveyor channel for the transport of granular and/or powdered materials. The pneumatic conveyor channel according to the invention can be applied particularly for the transportation of flying ashes of thermal plants, pulverized maize, wheat, coca, coffee and flour utilized in the agriculture and in the food industry as well as for transportation of cement of cement works and powdered plastic of the chemical industry.

Several aeration channels for the transport of granular and/or powdered materials are known. These channels comprise fluidizing layer made of a suitable material, on which the material to be transported is arranged in the channel. This is called the powder-space of the aeration-channel. The other part of the channel being formed under the fluidizing layer is the air-channel of the aeration channel. Supplying the air-channel by gas, particularly by air being needed for fluidization, the material in the fluidizing layer is generated into so called pseudoliquid and flows like a real liquid at a speed depending on the gradient of the channel. By feeding the inlet of the channel by further material the process can be made continuous.The operation of the known channels can be characterized in that the supporting space of them is not filled, the transportation of granular and/or powdered materials is effected by gravitation, the flow of the material is similar to the flow of materials in channels having an open surface, and that predetermined quantity of air have to be blown through unity surface of the fluidizing layer to effect a fluid. The predetermined quantity of air is dependant on the material to be transported and the quantity of the material of the fluidizing layer. Since the flow of the material is in the open, the air exhausted from above the powder layer can not be utilized once again. It means that the quantity of air needed for the transportation is increasing proportional to the distance of transportation.The fluidizing air comes out of the material and leaves it through the powder space over the material and the openings arranged for this purpose over the material. The disadvantage of the known devices is that the exhausted air have to be purified by means of suitable filter means according to the demands and specifications of the environmental protection. The dimensions and prices of such filter means are increasing in direct proportion to the length of the channel, and it needs energy in addition to the energy needed to upkeep the channel.

There are further devices of prior art for pneumatic transportation of powdered and/or granular materials which working continuously of discontinuously by means of several feeding means, transporting the material in a closed pipeline. The transport channel of these devices is filled in its whole crosssection and the transport is effected by using the pressure energy of the gas particularly of the air. The common disadvantage of these devices is that they need high speed-energy in addition to the pressure-energy in order to held the material in motion. The speed of the most contemporary so called plug system is only 3-6m/sec and enables transport in very limited distances only.

The aim of our invention lies in developing a pneumatic conveyor channel for the transpor of granular and/or powdered materials, in which the material to be transported fills the whole cross-section of the channel and the transport in closed pipeline is not effected by the gravitational field as in cases of a real liquid but by the pressure extending uniformly in the liquid.

The invention is based on the recognition that the material to be transported fills the whole cross-section of the channel according to the invention and behaves liquidlike - it means that its motion is effected by pressure - when the material to be fluidized is arranged between two or more suitable layers permeable to air, and one of these layer is working as a fluidizing layer and the other as a filter layer.

The aim set is realized by a pneumatic conveyor channel for the transport of granular and/or powdered materials comprising material space, gas space and fluidizing pipeline; this device had been developed according to the invention in the manner that the material space, containing particularly in its whole cross-section the material to be transported is sorrouned at least by two gas spaces and the material space is being separated from each of the gas spaces by a lower fluidizing layer and by upper filter layer.

In a preferred embodiment of the channel the lower gas space is divided into gas inlet chambers for the fluidizing layer connected to each other, and the upper gas space is divided into gas outlet chambers for exhausting the fluidizing gas and being connected to each other.

It is further preferable if each of the inlet chambers and the outlet chambers respectively are connected in series and the fluidizing gas is of constant volume flow independent of the length of the channel.

The pneumatic conveyor channel according to the present invention is preferably formed so that the inlet chambers and the outlet chambers, respectively are connected parallel, and the volume flow of the fluidizing gas changes proportional to the length of the channel.

It is further advatageous if the channel is connected to known feeding means.

The pneumatic conveyor channel according to the invention will be described in detail by means of preferred embodiments by aid of the enclosed drawings, wherein Figure 1 shows the schematic diagram of a preferred embodiment of the pneumatic channel according to the invention, Figure 2 shows a cross-section taken along the line ll-ll of the channel of the Fig. 1, Figure 3 shows a further embodiment of the channel according to the invention, and Figure 4 shows a cross-section taken along the line IV-IV of the channel shown in Fig. 3.

Fig. 1 shows the schematic arrangement of a channel according to the invention of constant volume flow. The channel is divided by an upper filter layer 1 and a lower fluidizing layer 2 into gas spaces 3 and 4 a material space 6. Each of the two gas spaces 3 and 4 surrounding the material space 6 are divided into gas inlet chambers 7 and gas outlet chambers 8. The gas is being in this case air.

The chambers 7 and 8 are connected to the pipeline 5 transporting the fluidizing gas e.g.

air in such manner that the output of each gas outlet chamber 8 is connected to the input of the gas inlet chamber 7 following the outlet chamber 8 in the direction of flow of the material to be transported through the pipeline 5.

In Fig. 2 is to be seen that the pneumatic conveyor channel according to the invention is of cornered shape and the gas space 3 above and the gas space 4 under the material space 6 are symmetrically arranged. The air utilized as fluidizing gas enters the gas outlet chamber 7 and passes through the fluidizing layer 2 and fluidizing the materials to be transported in the material space 6. Passing through the fluidized material and filter layer 1 separating the material space 6 and gas space 3 the air leaves the output of the outlet chamber 8 and moves on in the pipeline 5 and enters the following lower inlet chamber 7, passing it and enters through the fluidizing layer 2 into the material to be transported, fluidizing it or holding it in fluid, then enters through the filter layer 1 a further outlet chamber 8. This cycle can be repeated as described above.

Fluidizing powdered and/or granular material and overcoming the resistance of the system is performed by the pressure energy of the air.

When the cross-section of the pipeline 5 is big enough the pressure of the air in any pair of two adjacent upper outlet chamber 8 and inlet chamber 7 is practically the same. From the pressure relation between the upper and lower chambers follows that pressure is exerted on the material the direction of which is the direction of decreasing pressure in the chambers, and this pressure is in balance with the friction resistance of the moving materials.

The air can be fed back from the last gas outlet chamber 8 to the inlet arranged at the input of the pneumatic conveyor channel according to the invention, so closed loop air circulation can be developed. The flow resistance of the upper filter layer 1 is increasing in dependence on the time owing to the settling of particles of material but choosing a suitable filter material depending on the material, a long operating time can be ensured or e.g. the filter layer 1 should be cleaned by known methods.

It is further preferable according to the present invention, if the channel is reversed and the task of the filter layer and of the fluidizing layer 2 is changed.

It is further advantageous if the chambers 8 are periodically counter flushed by using highpressure.

It is further preferable if the pneumatic conveyor channel according to the present invention is being operated by air the volume flow of which is increasing in dependence on the length of the channel. According to this embodiment the lower inlet chamber 7 and the upper outlet chamber 8 are interconnected through the pipeline 5 in the same chamber spacing, so the operation of them considering to the flow of gas can be considered as parallel. This embodiment can be seen in Fig.

3. There is a means e.g. a fan 9 arranged in the pipeline 5 connecting the chambers 7 and 8 and ensuring suitable flow-speed for fluidizing the air. The pressure of the material to be fluidized is constant along the length of the channel, thus force is needed to move the material input of the channel. This force can be e.g. the pressure of the tank but if can be a mechanical force too.

The advantage of the pneumatic conveyor channel according to the present invention lies in the transport of granular and/or powdered materials in a liquidlike fluid of optional suitable speed choosen according to the circumstances referring to liquids. This speed measured in the channel is about of 0,5-1,5 m/sec. The transport of the material can be realized by using minimal energy and without wearing the conveyor device and without damaging of the granular and/or powdered material during the transport.

Claims

1. Pneumatic conveyor channel for the transport of granular and/or powdered materials comprising material space, gas space and fluidizing pipeline characterized in that the material space containing particularly in its whole cross-section the material to be transported, is surrounded at least, by two gas spaces and the material space and gas spaces are separated from each other by using a lower fluidizing layer and filter layer.

2. Pneumatic conveyor channel according to claim 1, characterized in that the lower gas space is divided into gas inlet chambers for the fluidizing gas, and the upper gas space is divided into gas outlet chambers for exhausting the fluidizing gas, and each of inlet chambers and each of outlet chambers are connected to each other.

3. Pneumatic conveyor channel according to claim 1 or 2, characterized in that the inlet chambers and the outlet chambers respectively are connected in series and the fluidizing gas is of constant volume flow being independent of the length of the channel.

4. Pneumatic conveyor channel according to claim 1 or 2, characterized in that the inlet chambers and the outlet chambers respectively are connected parallel, and the volume flow of the fluidizing gas is changing proportional to the length of the channel.

5. Pneumatic conveyor channel according to claims 1-4, characterized in that the channel is connected to known feeding means.

6. Pneumatic channel according to claims 1-5, characterized in that the inlet chambers and outlet chambers of fluidizing gas are arranged interchangably.

7. A pneumatic conveyor for granular and/or powdered material, which conveyor contains a longitudinal channel for the material, at least one gas inlet space located below the channel and separated therefrom by a gaspermeable diaphragm and at least one gas outlet space separated from the channel by a gas-permeable diaphragm and also separated from the gas inlet space(s).

8. A conveyor as claimed in claim 7, wherein the or each gas inlet space is directly connected to the or a gas outlet space by a pipeline.

9. A conveyor substantially as hereinbefore described in connection with and as illustrated in Figs. 1 and 2 or Figs. 3 and 4 of the accompanying drawings.