JPH0134900B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a multi-tube pneumatic transport system in which a constant air volume adjusting device is provided at a predetermined location of each pipe in the multi-pipe pneumatic transport system.

A conventional multi-tube pneumatic conveyance system will be described in detail later, and is diagrammatically shown in FIG. In such a system, the damper initially sets the amount of air flowing through each branch pipe to a predetermined value and continues operation in that state.
However, in reality, the amount of cargo flowing through each branch pipe varies greatly, and the amount of air flowing through each branch pipe also changes due to this influence. Therefore, when setting this predetermined air volume value, we empirically determined and set the air volume to obtain a wind speed that can air transport the powder and granular material even at the maximum mixing ratio of the powder and granular material that is considered to occur in each branch pipe. are doing. Therefore, this set air volume is considerably larger than that when considering only steady operation in which the mixing ratio of all branch pipes is constant. Therefore, the actual mixing ratio in each branch pipe is usually much lower than the maximum mixing ratio, resulting in an excessive amount of air flowing wastefully, increased consumption of air power, and wear of the duct.
For this reason, the air source motor and blower require an excessively large capacity, which not only increases equipment costs but also makes the operation extremely uneconomical. In addition, if an excessive amount of air flows through one branch pipe, the air volume in other branch pipes decreases, and depending on the mixing ratio in this case, powder and granules may stagnate in the pipe, or in the worst case, cause blockage. It also causes problems. As described above, the conventional pneumatic transportation system has the disadvantage that the design value may be excessively large and there are many troubles.

Therefore, an object of the present invention is to provide an air transport system that maintains the amount of air flowing through each branch pipe at a constant value and operates stably.

Furthermore, another object of the present invention is to reduce equipment and operating costs for pneumatic transportation.

According to the present invention, a part of each branch pipe system constituting the air transport system is provided with a constant air volume adjustment device that can respond to pressure fluctuations due to changes in the mixing ratio, etc., so that even if the mixing ratio of each branch pipe system increases or decreases, The configuration is such that a constant predetermined air volume is always maintained. That is, the present invention provides a system for transporting powder by flowing air through a large number of branch pipes communicating with a main pipe. a flow rate adjustment member installed near the constriction portion and movable in the axial direction of the housing; a biasing means for biasing the flow rate adjustment member in the upstream direction of the air flow; and a flow rate adjustment standard according to the amount of transported powder and granular material. and a manual adjustment means for setting a reference position of the flow rate adjustment member in order to adjust the value, the air flow is adjusted from the reference position set by the adjustment means according to the amount of powder or granular material transported. A constant air volume adjusting device is provided in which the flow rate adjusting member automatically moves according to the flow velocity to adjust the flow rate to a constant flow rate adjustment reference value by increasing or decreasing the cross-sectional area of the flow path, and each of the branches The present invention provides an air transport system characterized in that it is configured to control the flow rate of the pipes so as to maintain a predetermined ratio.

Next, the illustrated embodiments of the pneumatic transport system according to the present invention will be explained while comparing it with a conventional system.

FIG. 1 shows a conventional pneumatic transport system. Although a suction type is illustrated as a representative example, it goes without saying that the present invention can also be applied to a pressure feeding type.
In this system, the main pipe L has many branch pipes L ₁ , L ₂ , L ₃ . . .
Branched into L _o , each branch pipe has cyclones C ₁ , C ₂ , C ₃
...C _o , mixers M ₁ , M ₂ , M ₃ ... _Mo are provided, and the air volume is adjusted by dampers D ₁ , D ₂ , D ₃ ...D _o . The suction air from the blower 1 sucks powder and granules into each branch pipe from a mixer at an appropriate mixing ratio, separates the powder and granules with a cyclone, removes dust with a back filter 2, and exhausts the air. In this way, a certain wind speed (amount) is required to transport powder and granular materials by air, and this depends on the physical properties of the transported material, such as particle size, shape, stickiness, hygroscopicity, etc., and the mixing ratio with air. It is determined. In addition, the mixing ratio is always changing, and the range of fluctuation is quite large, so the damper opening degree, that is, the air volume Q to obtain the transport wind speed, is currently determined based on the value that is considered to be the maximum mixing ratio. are doing. However, under normal conditions, the mixing ratio in each branch pipe is smaller than the imaginary maximum mixing ratio, and this amount is wasted without being used as air for transporting the powder or granules. In addition, if the amount of powder and granules supplied from a certain branch pipe, for example, the mixer M _o of L _o increases, and the mixing ratio increases, the air volume of this system will decrease, and other pipe systems that are easy to flow will be
It flows dispersed into L ₁ , L ₂ , ...L _o-1 . The dispersed air volume of these pipe systems continues to flow without being restrained and is wasted as wasted wind speed. If the mixing ratio further increases, the above phenomenon will be accelerated, making it impossible to transport the powder and granules, and eventually this system L _o may even become clogged. This is because the damper is set so that the amount of air that should flow to _Lo can easily flow to other pipe systems.

Therefore, in the present invention, each branch pipe system is equipped with a constant air volume adjusting device V ₁ having a buffering capacity instead of a damper.
V ₂ , V ₃ ...V _o are provided (see Figure 2). As this constant air volume adjusting device, an example as shown in FIG. 3 can be used.

This device has a bench lily type housing 3 having a constriction part 8, and near the constriction part of the housing 3, a cone 4, which is a flow rate adjusting member, is movable in the axial direction of the housing 3, that is, in the direction of air flow. It is set up like this. Also, a spring 5 is attached to the cone 4.
is attached and biased in the upstream direction of the airflow. The reference position of the cone 4 is determined by operating the manual adjustment means 6 and moving the rod 7 in the axial direction so that the flow rate adjustment reference value can be adjusted according to the amount of powder and granular material transported. It is adjustable.

Here, the reference position setting of the cone 4 by the manual adjustment means 6 may be performed initially, or the set value may be changed during transportation of the powder or granular material.

Therefore, it is possible to select an appropriate flow rate adjustment reference value according to the type, amount, and shape of the powder or granular material to be transported, and even if these values change during the process, the flow rate can be adjusted by operating the manual adjustment means 6. Since the reference value can be changed, a suitable predetermined air volume can always be sent to each branch pipe.

When the wind speed of the air flow increases as indicated by the arrow in the housing 3 around the reference position corresponding to the flow rate adjustment reference value, that is, when the wind pressure of the air increases, the spring 5 is compressed and the cone 4 is moved downstream. Move in the direction (to the right as seen in Figure 3) as shown by the solid line,
The gap between the cone 4 and the housing 3 is narrowed, that is, the cross-sectional area of the flow path in the throttle section 8 is reduced, thereby increasing the flow resistance and reducing the air volume. Conversely, when the wind speed inside the housing 3 decreases and the wind pressure weakens, the spring 5 expands and moves the cone 4 in the upstream direction (third direction).
(to the left in the figure) as shown by the dotted line, increasing the gap with the housing 3, that is, increasing the cross-sectional area of the flow path in the throttle section 8, weakening the flow resistance, and increasing the air volume. do. By providing this constant air volume adjustment device in each pipe system L ₁ , L ₂ , L ₃ ...L _o in this way, each pipe system always maintains a constant air volume.
Only Q' can be made to flow. According to experiments conducted by the present inventor, a constant air volume Q' is a value that is approximately 20-30% smaller than the air volume Q in the case of a conventional pneumatic conveyance system, and the design values of the blower and motor required for this purpose are Not only will the amount of air become smaller, but the amount of air blown will also be smaller, so operating costs (electricity) will also be significantly reduced (approx.
20-30%) has been confirmed to decrease. The present invention is preferably applied to a system having a relatively large number of branch pipes, and is particularly effective to be applied to a system having five or more branch pipes.

In this way, in the conventional pneumatic transport system, the air volume was wasted within the system, but in the present invention, wasted air volume is avoided by the constant air volume adjustment device. In the conventional system, the damper setting value was determined based on the virtual maximum mixture ratio, so it was abnormally large.
Like the constant air volume adjusting device of the present invention, it was unable to function as a resistance against an increase in airflow speed and an acceleration action against a deceleration of an airflow. Therefore,
In the present invention, it is possible to cope with load fluctuations, and the constant air volume value during steady operation is significantly smaller than the conventional set value based on the virtual maximum mixing ratio. Therefore, as mentioned above, the capacity of the motor and blower used as the system's air source can be reduced, significantly reducing running costs, especially power consumption, and reducing wear and tear on the duct system, reducing system maintenance costs. can. Further, according to the pneumatic transportation system of the present invention, the flow rate adjustment reference value can be appropriately selected or changed by the manual adjustment means depending on the type, amount, and shape of the powder or granular material at the beginning or during the transportation of the powder or granular material. This allows a suitable amount of air to be sent to each branch pipe at all times.

The above-mentioned effects could not be achieved by using a damper to set the air volume to a predetermined value, and the present invention is particularly effective in terms of power saving.
This makes it possible to realize stable operation of the pneumatic transport system with low energy consumption.

[Brief explanation of drawings]

FIG. 1 is a diagram of a conventional pneumatic transportation system, FIG. 2 is a diagram of a pneumatic transportation system according to the present invention, and FIG. 3 is a cross-sectional view of a constant air volume adjusting device used in the system of FIG. L... Main pipeline, L ₁ ..., L _o ... Branch pipeline, D...
Damper, C...Cyclone, M...Powder mixer, V...Constant air volume adjustment device, 1...Blower, 2...
...filter, 3...housing, 4...cone,
5... Spring, 6... Position adjustment means, 7... Rod, 8
...Aperture section.

Claims (1)

[Claims] 1. In a system for transporting powder by flowing air through a number of branch pipes communicating with a main pipe, there is provided a bench lily type housing having a constriction section at a predetermined location of each branch pipe, and a flow rate adjusting member installed near the constriction portion and movable in the axial direction of the housing; a biasing means for biasing the flow rate adjusting member in an upstream direction of the air flow; and a flow rate adjusting member according to the transport amount of the powder and granular material. In order to adjust the reference value, it has a manual adjustment means for setting a reference position of the flow rate adjustment member, and the air flow is adjusted from the reference position set by the adjustment means according to the transport amount of the powder or granular material. A constant air volume adjusting device is provided, the flow rate adjusting member is configured to automatically move according to the flow rate of the flow path, and the flow rate is adjusted to a constant flow rate adjustment reference value by increasing or decreasing the cross-sectional area of the flow path. A pneumatic transport system characterized by being configured to control the flow rate of a branch pipe to maintain a predetermined ratio. 2. The pneumatic transport system according to claim 1, wherein the number of branch pipes is five or more.