Description

Title of Invention: AIRFLOW FABRIC FOR A PNEUMATIC CONVEYOR

Technical Field

[0001] This invention relates to a conveyor for carrying small granular particles such as cement on a flat ground trough horizontal axis.

Background Art

[0002] Different methods and devices have been used for the pneumatic conveying of particulate and powdery bulk goods such as cement, for example low energy trough conveying and flexible pipe conveying, by means of screw sluices. The disadvantage of trough conveying is the downwardly inclined conveying pipeline required, which is only possible in rare cases. Disadvantages of conveying by pipe include the generally high conveying speeds required and therefore the high outlay on energy. There even exists pneumatic channel conveyors made of synthetic material. Those conveyors are suitable for only downwardly inclined. Here some of the air flow required for conveying is blown into the bottom of the conveying pipe by means of aeration elements in order to render the bulk goods to be conveyed flowable or to fluidize them, while the remaining, in most cases greater proportion of air flow serves as conveying air. The main disadvantage of those conveying pipes is inevitable continuous airflow requisite. The problem with the fluidized conveying pipe is fluidizing air, which is also termed fluid gas. Synthetic fabric, with thicknesses of approx. 4-5 mm and pressure losses of approx. 0.01 bar, is normally used for the fluidization, conventionally with specific fluidizing flow rates of to 1.0 m3/m2min. The flow rates through the fluidizing fabric are determined from the free cross-section and are of the order of 0.1-0.3 m/s. This is a power of ten below the suspension rate of powdery goods such as cement which require 2m/s flow rate, which is the fluidizing fabric does not have sufficient energy to fluidize the goods to be conveyed fully at the top, and on the other hand the flow is undirected and no pulse is transferred to the bulk goods in the direction of conveying. Furthermore, the distribution of the fluidizing air underneath the fluidizing fabric is important. On the one hand an excess pressure, relative to the pressure in the conveying pipe, must exist underneath the fluidizing fabric so that the flow does not recoil and very fine particles penetrate the fluidizing fabric, and on the other hand it must be ensured, by expensive air flow control and air flow throttling, that if there are a plurality of pipe sections the air is also fed from the generating fan or compressor into the first segment at the beginning of the conveying pipe line and does not flow out of the conveying pipe line on an element further behind in the direction of conveying with a lower counter pressure. Such air flow throttling is always associated with an ap-

preciable energy loss. If the air flow throttling is to be avoided individual fans with staged pressures must be used in practice for each aerating element, but this is too expensive and is not practical.

[0003] Pneumatic belt conveyors actually operate by use of downward inclination. Those conveyors are alternative to the pneumatic pipeline conveyors. The powder materials in granular form which are easily flowable are conveyed. The flowed and fluidized materials are conveyed in the pipelines which are inclined at least %4 and energy consumption is therefore reduced. The material which is fluidized by air flow from the bottom of the belt which has a specific permeability rates, having multiple layers and porous structure is conveyed in the two part pipe due to the result of inclination and gravity force. Airflow is generated by a fan blower. The belt should be uniform in order to let the air flow from bottom to the upside. The powder material is pushed up by the effect of air flow from the bottom to the upside of the belt and therefore the powder material is fluidized. The fluidized powder material is then conveyed downward trough the inclined belt. Simple design, low cost, less energy consumption, eligibility of conveying high value of the material and further ease of installation is the general advantageous aspects of this system. However this system is suitable for use in spiral conveyors and vibrating or box type conveyors. Main disadvantages of this system are the structure and inevitable inclined design. Due to the structure and inclined design wide and open areas are needed for the system to operate.

[0004] Lately a new invention related to pneumatic belt conveyor is disclosed in US

2007/0183854A1 patent document. The aim of this invention is claimed to convey the material by less energy by way of using a belt structure made of metal wires which is proposed to be a substitute to synthetic conveyor belts. In this claimed pneumatic conveyor belt sintering by way of cylindrical press technique is used to produce the belt. Each of the metal weaving layers is sintered under high temperature and connected to each other and a multi layer metal structure in thickness of 2mm is produced. Each of the metal weaving layers is weaved by using thinner metal wires than the wires used in the previous metal layer underneath in order to increase the air flow rate and consume less energy in the conveying process. The air permeability of the belt is determined trough the cylindrical press process. In this invention there is still a need of further air flow passing horizontally through the pipeline in addition to the air flow from the bottom of the conveying belt. In contrast to our invention conveying is not achieved by such a structural and weaving methods of the belts. Furthermore the structure of the claimed belt mentioned in US patent is undesirably set widely apart, the production process is complicated and the actual costs are pretty high.

[0005] One another invention is disclosed in Japanese patent JP06154584. The aim of this invention is conveying the solid particles by way of directing fluidized material.

However the diagonal cross sectional structure is achieved by differential angular cylindrical pressing of the layers. Since the structure of the belt is inevitably and undesirably set widely apart the air flow rate happens to be faster than desired and therefore an undesirable boiling occurs instead of fluidizing. Furthermore due to the undesired flow rate, some parts of the belt may not receive enough flow rates for fluidizing the granular particles. That is to say in order to manufacture a conveyor belt it should be designed as every single part of the belt should be air permeable at the same value. From the opposite point of view if the belt is weaved to be much more strict or narrow than the desired it would be less permeable than the desired value and therefore fluidizing and conveying of the powder material would not occur due to deficient flow rate at the top of the belt. Japanese patent - JP06154584 - describes a pneumatic belt made of fabric which is weaved so loose and thin and one layer of it is reversed and scrolled as being alternative to the known belts which are made of two layer fabric having orthogonal and alternate angles. This document further discloses the process for producing the belt how it is manufactured for use of such way giving the details of the material (stainless steel wire-SUS316) of the belt. In the disclosed process spot weld techniques is used to fix the structure. The belt is even heated up to the 1060° C for one hour and cooled later on. The structural embodiment of the disclosed belt in the Japanese patent cannot be claimed to be used for conveying cement or cement like highly intensive materials. This invention is therefore cumbersome for use in the cement manufacture industry. That is also a reason why those belts do not exist in the real cement industry. The disclosed invention in the Japanese patent may only be used for conveying law density material and the process steps of this invention is pretty long and quite expensive which are the main cumbersome points of this invention.

Disclosure of Invention

[0006]

Technical Problem

[0007] In this claimed in invention conventional synthetic material is used for producing the pneumatic conveyor belts. This point indicates the first difference from the US patent document which even reduces the costs. Furthermore in US patent, each of the metal weaving layers is weaved by using thinner metal wires than the wires used in the previous metal layer beneath in order to increase the air flow rate and consume less energy in the conveying process. However while saving energy in such a way, there is still a need of further horizontal air flow in to the pipeline which requires much more energy and therefore the whole system becomes uneconomic. The sintering process and application of heat bring out the system to be costly to produce. In US patent there

is no explanation about the weaving structure of the belt as described in our claimed invention. [0008] In this invention instead of weaving layer by using thinner metal wires than the wires used in the previous metal layer and sintering via applying heat, different cross sectional structural embodiment and weaving method is used to achieve the result. The proposed system therefore reduces the production costs and enables the latter weaving looms to be used by simple modifications. In contrast to the previously explained pneumatic conveying belt systems there is no need for horizontal flow in to the pipeline in addition to the air flow beneath the belt. The air permeability of the claimed belt is achieved by the parameters used in the weaving process in contrast to cylindrical press technique explained in the US patent document. By way of the claimed process and claimed structural embodiment of the belts cements could be conveyed at the inclination of 0-40°. As explained detail above conventional pneumatic conveying belts made of synthetic material are not suitable for conveying cement like material without additional horizontal air flow. In this claimed invention it is not a prerequisite to heat the belt up to the high degrees and cooling down later on (JP Patent it is a requisite to heat the belt up to 1060° C for one hour and cool down later on). Furthermore tightly weaved, 4-5 layer hard textile is used instead of loose and slimy fabrics. Instead of deforming the weaved fabrics, textiles having diagonal cross sectional structure are produced. The claimed conveying belts could be directly offered for sale without any further processing. The structural embodiment of the claimed conveying belts is even resistant against the powder material penetration conveyed on it in advantage against the other pneumatic conveying belts.

[0009] Finally that is to say the claimed pneumatic conveying belts are cost effective, could be produced by making small modification in the conventional weaving looms without a need of further processing steps or further investment and it is proven that there is no need for additional horizontal air flow in to the pipeline.

Advantages of the invention

[0010] The main aim of the invention is to produce a cost effective angular pneumatic conveying belt which is suitable for carrying mainly cement or cement like powder materials at the inclination between 0° 4°. The claimed invention is proposed to be used particularly in the cement industry.

[0011] In figure 1 and 2 schematic views of conventional pneumatic conveying belts are described. As it is shown in figure 1, due to the straight weaving the conveying pipes should be inclined at the degree of 4-14.

[0012] In figure 2, air permeable woofs (5) between the warp yarns (4) and woofs (3) at the top and at the bottom is shown. In this figure it is shown that the air permeable woofs

are weaved to assemble a straight line instead of assembling an S figure. [0013] Subject of the claimed pneumatic conveying belt is weaved as shown in figure 5 in order to let the conveying the powdery material without an inclination and additional horizontal air flow. The powdery particles ascent by the effect of air flow from the bottom of the belt then falls down due to the gravity at the point where the flow power finalizes (Figure 3). The fallen particles are ascended again by the air flow through the next air passage on the belt. Since the air passages are weaved to be angular the powdery particles shall be moved forward and conveyed without the need of an inclination. In figure 4, the structural embodiment of the claimed pneumatic angular conveyor belt and its position in the pipeline is shown. In this claimed embodiment vertical warp yarns (4) at the desired thickness and desired number (4 stage is exampled in figure 5) and woofs (3) are weaved transversely (at least two transversely weaved woofs for each layer; each woof assembling a horizontal S figure and being in the shape of (∞) when weaving is finished). Air preamble woof (5) is then weaved to assemble a "S" shape below the bottom layer consist of warp yarns (4) and woofs (3) and top layer consist of warp yarns (4) and woofs (3). The distinctive point of this weaving technique is the pivotal position of the warp yarns (4) in compare to the latter one just at the below or above them. The warp yarn (4) in the each layer should not be arranged in the same right angle. Each of the warp yarn(4) at each layer should be positioned a little forward or backward compared to the latter one just at the above or below ones. These positioning shall create an acute angle between the air permeable woof (5) axis and warp yarn (4) axis. Those warp yarns at each layer should be totally symmetric at that acute angle to latter one at above or below layer. As a result of this positioning the air flow directed from any angle beneath the belt, shall flow through the conveying direction at an acute angle with the horizontal axis and the powdery material are conveyed without the need of a additional horizontal air flow and inclined structure. The claimed belt is made of synthetic material in the present invention. At least two weaving layers are enough to achieve the aims of this invention. However four weaving layers are preferable. It is also preferable for the claimed pneumatic conveyor belt to be made of synthetic having a thickness of 5 - 6 mm, having a weight of 3400-3700 gr/m2, having an air permeability of 2.250 It/dm2, Hr. @ 1000 Pa ( + - ) 100, and being the continuous working conditions mostly 140° C. [0014] Since the weaving is not made of sintered metal material, the present invention is claimed to be advantageously cost effective. The waving looms designed for weaving metal materials should be designed especially for this aim and therefore they are quite expensive. The conventional weaving looms are capable of manufacturing the claimed conveyor belts via modifying them to weave each layer being totally symmetric at that acute angle to latter one at above or below layer in the diagonal axis.

Brief Description of Drawings

[0015] Figure 1: Lateral cross-section view of the inclined (conventional) pneumatic conveyor belt [0016] Figure 2: Structural cross-section view of 4 layer inclined (conventional) pneumatic conveyor belt [0017] Figure 3: Lateral cross-section view of the angular (present invention) pneumatic conveyor belt [0018] Figure 4: Diagonal cross-section view of angular (present invention) pneumatic conveyor [0019] Figure 5: Structural cross-section view of 4 layer angular (present invention) pneumatic conveyor belt

[0020] Explanations of the parts shown in the figures: [0021 ] 1. Fluidizing Air Flow inlet [0022] 2. Pneumatic conveyor belt [0023] 3. Woofs [0024] 4. Warp yarns [0025] 5. Air preamble woof [0026] 6. Air Flow direction