JPS5928498B2 - Method for reducing pressure loss in acceleration section in pneumatic conveyance pipeline - Google Patents

Description

[Detailed Description of the Invention] Currently, municipal waste is collected and transported by garbage trucks, but this poses problems such as high costs due to rising labor wages, pollution problems such as the scattering of bad odors caused by garbage trucks, and traffic congestion, as well as social problems. pneumatic waste transportation systems are attracting attention as a new alternative collection system.

However, not only pneumatic transportation of municipal waste, but also any pneumatic transportation in general, requires more power (blower pressure (P) and air volume Q) than other transportation devices (conveyors, etc.). This is considered to be a major drawback, and the greatest aim of the present invention is to reduce this required power.

In general pneumatic transport as well as waste pneumatic transport, the wind speed within the transport pipe is generally constant.

However, there are those that are designed to locally change the wind speed by changing the horizontal and vertical pipe diameters, or those that are structurally sleeve-type and have steps for horizontal and vertical expansion and contraction, such as grain newmar. .

However, there have never been any models in which the diameter of the pipe is changed over the entire region (section) in order to reduce pressure loss in the acceleration region, or in which a device that changes and controls the wind speed is installed.

The equations of motion of objects to be transported, i.e., particles, in these conventional pneumatic transportation devices can be expressed as equations 0 and 0, and if this is shown diagrammatically, it can be expressed as shown in Figure 1. .

m: Mass of particle Us Two rice grain speed t: Time g: Gravity, d・7'aUr R: Resistance = anti-crab Cw -X - 2g Ur: Relative velocity = Ua-Us Ua: Speed of air γS: Transported material Specific gravity γa: Specific gravity of air Cw: Resistance coefficient d: Particle diameter m: For upward transportation 10: For descending transportation Also, in the case of transport by sliding on the bottom of a pipe, such as garbage transport, the lump can be regarded as a single capsule. For example, the equation of motion of the capsule can be expressed as equation 0, and if this is shown diagrammatically, it can be expressed as shown in FIG.

Ws: Weight of the capsule C: Weight of the capsule Va: Wind speed in the transport pipe fs: Coefficient of friction As: Pressure-receiving area of the capsule All of these 000 formulas are basically based on the same concept, and from these equations of motion, the particle or The relationship between capsule speed and time is as shown by curve 1 in FIG. 3.

According to this figure, the particle (capsule) velocity is thought to change moment by moment over time, and eventually reach a constant steady velocity.

This curve l varies depending on the conditions (particle diameter, particle mass, capsule pressure receiving area, wind speed, drag coefficient, friction coefficient, etc.), but it is an existing fact that it has been introduced in various literature.

In any case, the particles or capsules have an initial velocity of O due to the wind speed in the transport pipe, but the initial velocity becomes large.
and the next dUs dC receives the -or- -th smaller acceleration
(This is clear from the * mark in Figure 3), final velocity Ust
Or reach Ct.

On the other hand, when looking at actual measurement curves of pressure drop, distance, and time for pneumatic transportation and garbage transportation, Figure 4 shows the correlation between pressure drop and distance for continuous transportation (general pneumatic transportation), and Figure 5 shows the correlation between pressure drop and distance for continuous transportation (general pneumatic transportation).
The figure shows the relationship between pressure drop and time for garbage transport (intermittent transport).

FIG. 5 shows garbage transportation, that is, when a garbage group is transported by a wind speed of Va by opening the discharge valve 32 in which a certain amount of garbage is stored in the chute 31 in FIG. The time (
(or distance) and pressure changes are plotted on an oscillograph.

As is clear from FIGS. 4 and 5, in both cases, either the pressure drop is large during the initial acceleration of transportation, or the pressure rise is large during the initial acceleration region of transportation.

The present invention was made for the purpose of reducing the sudden drop or rise in pressure at the initial stage of transportation as described above, making the blower head smaller, and thereby reducing overall power consumption. A bypass pipe equipped with a valve is provided in the acceleration section in the middle of the pipeline of the machine, and when the transported object reaches the acceleration section, the valve is opened, and then the valve is closed over a certain period of time, thereby reducing the speed of the transported object. It is characterized by gradually accelerating the passing speed of the object to a steady speed before reaching the acceleration section.

In addition, for a certain transport distance, a certain amount of transported goods,
When transporting by rapid acceleration method and gradual acceleration method, the following relationship holds true (Figure 7).

Rapid acceleration method Gradual acceleration method Maximum transport pressure ΔP1> ΔP2 Acceleration time tl<t2 Total transport time T1<T2 Required transport A1A2 Energy T2-T1 Regardless of the change, it is purely mechanically constant, and therefore, the reduction in transport pressure due to the gradual acceleration method appears as an extension of the transport time.

That is, from the point of view of energy (the energy required to raise the transported object to a certain constant speed), it goes without saying that the rapid acceleration method and the gradual acceleration method are the same.

However, the present invention characterizes the phenomenon of ΔP1>ΔP2,
The purpose is to reduce equipment power (air source power).

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following, the principle of the present invention will first be explained in detail, and then the embodiments will be explained in detail.

FIG. 8 shows a curve C- shown in FIG.

In FIG. 8, l indicates a C- curve at a constant wind speed, and 13 indicates a constant acceleration curve.

In the present invention, when objects to be transported (capsules, particles, etc.) are transported at a constant wind speed, the particle speed is l, but by accelerating more slowly than this, for example, 11°12.141
The purpose is to provide a device such as No. 15 that causes less pressure rise than conventional devices.

Now, three representative curves of l, 13, and 15 in FIG. 8 are shown in FIG.

In general, goods to be imported are transported within transport pipes.
This is due to the velocity energy due to the wind speed in the pipe, and as a result, it appears as a drop ΔP of the pressure heads (pressure heads necessary for transportation) at two fixed points.

If the diameter of the transport pipe is d, Each can be expressed as

Although the flow within the transport pipe is complex, it goes without saying that the pressure drop between two fixed points and F=mα are in a proportional relationship.

In other words, the relationship holds true.

When this relationship is applied to FIG. 10, the relationship shown in FIG. 11 is established.

That is, l (constant wind speed transport single-minded acceleration) → initial pressure dog 13 (wind speed change - uniform acceleration) → pressure constant 15 (wind speed change - gradual acceleration) → pressure gradual increase ΔPl>Δ
The relationship Pl 5 > ΔP13 holds true.

In this way, the curve l located below the 1st curve in FIG.
It is clear that both 1.12 y 13 and 14.15 require a smaller pressure than ΔPl.

Therefore, the main problem of the present invention is how to change the speed of the transported object over an hour, or in other words, change the acceleration so that the curve is located below the curve 1.

It goes without saying that the above principle can also be applied to the acceleration part in the middle of the pipeline.

Figure 12 shows acceleration sections 41, 42.4 in the middle of the pipeline.
Schematic diagram of a pneumatic transport aircraft with 344 (45 is a separator 46
indicates the acceleration area 4142.44 in Fig. 12.
An example of the pressure drop in is shown in the graph of FIG. 13.

In FIG. 13, the fact that there is no part corresponding to the acceleration region 43 in FIG. 12 is omitted because 43 is considered to have almost the same curve as the acceleration region 41.

Figure 13A shows an example of pressure loss in the case of intermittent transportation,
From this example, by reducing the shaded area, the blower 4
It can be seen that it is possible to reduce the suction pressure of No. 6.

In addition, the case of continuous transportation is shown in Figure 3, and from this example, Δ
It can be seen that by reducing P4□ and Δ''44, the total pressure of the blower 46 can be reduced, and therefore the power can be reduced.

Embodiments of the present invention will be described in detail below based on the drawings.

As shown in Fig. 14, if you want to adjust the air volume only between A and B of the transport pipeline 1, install a bypass pipe between A and B.
A bypass valve 3 is provided in the middle of the bypass pipe 2.
If the air volume Qb is bypassed by providing
The air volume in the pipeline 1 between B can be reduced to Q-Qb.

Therefore, in the pipeline 1 outside floor plan A-B, the wind speed V is maintained based on the air volume Q, and only within the space between A and B, the air volume Q is maintained.
- The wind speed vb can be maintained under Qb.

The transportation state of the transported object in the pipeline having such a structure is as follows: First, when the transported object reaches point A, the bypass valve 3 is opened, and then the bypass valve 3 is gradually closed over a certain period of time t. As it closes, A of pipeline 1
As shown in Figure 15A, the air flow between -B rapidly decreases from Q to Q-Qb, and then becomes Qb=0 over a certain period of time t.
The air volume gradually returns to Q from Q-Qb.

Therefore, as shown in Figure 15, the change in wind speed that accompanies this change in air volume suddenly slows down from ■ to vb at point A, and gradually increases from vb to V over a certain period of time t. Return to the original V.

As described above, it is possible to adjust the wind speed only in a certain section of the pipeline without affecting other sections.

Therefore, the acceleration state of the transported object can be gradually accelerated in the middle of the pipeline, so that the acceleration loss in the middle of the pipeline can be reduced.

In this way, the locations in the pipeline where acceleration is required, that is, the locations where the device of the present invention is applied, are the locations where the transported material has been forced to decelerate. explain.

Figure 16A is an example where there is an acceleration area 10' at the outlet of the curved pipe section 10, and the opening in Figure 16 is an example where there is an acceleration area 11' at the entrance of the inclined pipe section 11. In this case, a bypass pipe 2 is provided in each acceleration region 10', 11', and a bypass valve 3 is provided in the middle of the bypass pipe 2.

Further, FIG. 16C shows an example of the spiral ascending pipe section 12,
In this case, as shown in the figure, a bypass pipe 2 is provided spanning from the inlet to the outlet of the spiral rising pipe section 12, and a bypass valve 3 is provided in the middle of the bypass pipe 2.

In this way, in both cases (a), (b) and (c), the transported object once collides with the tube wall, is decelerated there, is gradually accelerated again, and eventually returns to a steady speed.

Further, FIG. 17 is an application example of the dust chute type vacuum transport system, and shows a case where dust chute groups 13 and 14 are separated from each other and collection is started from dust chute group 13.

That is, after the dust in the chutes of the dust chute group 13 has been completely fed into the pipeline 1, the dust chute group 1
When the garbage in the chute No. 4 is thrown into the pipeline 1 (after the transported material from the dust chute group 13 passes through the dust chute group 14), as shown in Fig. 1γ, the dust chute group 14 at the front end is connected to the pipeline 1. A bypass pipe 2 is provided from the front of the position where the dust chute group 14 at the rear end communicates with the pipeline 1 to the rear of the position where the dust chute group 14 at the rear end communicates with the pipeline 1, and a bypass valve 3 is provided in the middle of the bypass pipe 2. It is possible to gradually accelerate the dust in the dust chute group 14 while keeping the dust transport wind speed in the chute group 13 constant.

Although the vacuum suction type has been mainly described above, it goes without saying that the pressure feeding type can also be applied in exactly the same way.

That is, FIG. 18A shows an application example for intermittent transport, and in the figure, 21 is a blower, 22 is a charger,
23 indicates an acceleration region, and 1, 2.3 indicate a pipeline, a bypass pipe, and a bypass valve, respectively, as described above.

Furthermore, in any of the above embodiments and application examples, in order to prevent the transported materials from flowing into the bypass pipe 2, a device for preventing the transported materials from flowing into the bypass pipe 2, such as a filter, is installed at the bypass branch and the confluence point. Needless to say.

According to the method of reducing pressure loss in the acceleration section in a pneumatic transportation pipeline of the present invention, the pressure loss in the acceleration region can be reduced;
The pressure head of the blower can be lowered accordingly.
Less driving power is required.

Furthermore, when transporting with the same power, the transport capacity can be increased.

■ By gradually closing the valve of the bypass pipe from the open state over a certain period of time, it is gradually accelerated to a steady speed, so the gradual acceleration time of the transported object can be controlled arbitrarily, and there is little load fluctuation on the blower.
Load fluctuations of the drive source are also reduced and can be kept constant.

■ The speed is adjusted by operating the bypass pipe valve,
Since air from outside the line is not taken in, it can be used not only as a suction type but also as a pressure feed type.

It can produce excellent effects such as

[Brief explanation of drawings]

Figures 1 to 7 are diagrams explaining the method of movement of transported objects in general pneumatic transport. Figure 1 is a schematic diagram of a single particle in a vertical riser pipe, and Figure 2 is a capsule sliding at the bottom of the tube. Fig. 3 is a graph showing the curve C-; Fig. 4 is a graph showing the pressure envelope curve at each point in continuous transportation;
The figure is a graph showing the p- curve in intermittent transportation, FIG. 6 is a schematic diagram of a transportation pipeline in garbage transportation, and FIG. 7 is a pressure comparison graph between the rapid acceleration method and the gradual acceleration method. 8 to 13 are diagrams related to detailed explanation of the present invention, in which FIG. 8 is a graph showing C- as a curve, FIG. 9 is an enlarged graph of C- as a curve, and FIG. 10 is a graph showing α- as a curve. Graph showing a curve, 1st
Fig. 1 is a graph showing Δp- as a curve, Fig. 12 is a schematic diagram showing acceleration regions in the middle of the pipeline, Fig. 13A is a graph showing pressure changes in the case of intermittent transportation in each acceleration region of Fig. 12, The opening in FIG. 13 is a graph showing pressure changes in the case of continuous transportation, similar to FIG. FIG. 14 is a schematic diagram according to an embodiment of the present invention. FIG. 15A is a graph showing changes in air volume in the acceleration region (between A and B) in FIG. 14, and FIG. 15A is a graph showing changes in wind speed similarly to FIG. 16 to 17 are schematic diagrams of application examples of the present invention, in which FIG. FIG. 17 shows an example of application to a pipeline having a group of dust chutes. Figures 18A and 18A and 18B respectively show application examples of intermittent pumping transport. 1...Pipeline, 2...Bypass line, 3...Bypass valve, 10...
...Bent pipe section, 10'...Acceleration region, 11...
... Inclined tube section, 11'... Acceleration region, 12...
...Spiral rising pipe, 13.14...Dust chute group, 21...Blower, 22...
・Charge pickle, 23... Acceleration range, 31...
...Chute, 32...Discharge valve, 33...Specific point, 41°42.43,44.
...Acceleration part, 45...Separator, 46.
...Blower.

Claims (1)

[Claims] 1 A valve is provided in the acceleration section of the pipeline of the pneumatic transporter) <Ipass pipe is provided, the valve is opened when the transported object reaches the acceleration section, and the valve is then closed over a certain period of time. A method for reducing pressure loss in an acceleration section in a pneumatic transportation pipeline, characterized by gradually accelerating the passing speed of a transported object to a steady speed before reaching the acceleration section.