JPH046623B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a pneumatic transport device for plug transporting granular material.

[Conventional technology and its problems]

It consists of a closed pressure tank and a transport pipe connected to the tank, and by supplying compressed air in pulses to the transport pipe, the granular material discharged from the closed pressure tank is transported as a plug along the transport pipe. A pneumatic transport device is known. Plug transport involves forming pressure air layers (pulses) and powder aggregate layers (plugs) alternately in the transport pipe, and the pressure difference between two pulses adjacent to the plug causes the material to permeate through the plug. This method uses the acting force of pressurized air, or "wedge force," to propel the powder or granular material, but if the granular material becomes clogged in the transportation pipe for some reason, the pulse for normal transportation will be used as described above. This blockage cannot be cleared just by sending compressed air, and eventually the transport action stops.

In view of the above-mentioned problems, the present applicant first proposed a pneumatic conveying device that prevents the blockage of the granular material in the transport pipe and ensures continuous transport of the granular material. By supplying compressed air in pulses to a connected transport pipe, the powder material discharged from the closed pressure tank is transported along the transport pipe as a plug, and at least one part of the transport pipe is connected to the transport pipe. An air introduction means equipped with a pressure detection means is provided to detect the pressure inside the pipe at the location, and when this pressure is higher than a predetermined value, compressed air is introduced into the transport pipe via the air introduction means. A pneumatic transport device has been proposed which prevents clogging of the powder material in the transport pipe. However, when the granular material is completely discharged from the sealed pressure tank and transport pipe, air is generally introduced into the sealed pressure tank to discharge the remaining amount, and this air flows through the transport pipe at high speed. ,
The particulate material is in a suspended state, and the air introduction means generally has a gap, through which the particulate material tends to enter the recess or hollow part and accumulate there. In some cases, during normal plug transportation, the powder material may become clogged, and even if air is sent through the air introduction means to prevent this, the flow does not reach the inside of the transportation pipe at a large flow rate, preventing the blockage. There are things I can't do. Furthermore, the pressure detection means may not operate and the purpose may not be achieved.

[Problem that the invention seeks to solve]

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an air transport device in which an air introduction means for preventing blockage can always operate normally.

[Means for solving problems]

The above object is to supply compressed air in pulses to a transport pipe connected to a closed pressure tank, thereby transporting the powder material discharged from the closed pressure tank along the transport pipe as a plug. , an air introduction means equipped with a pressure detection means is provided at at least one location of the transport pipe to detect the pressure inside the pipe at the location, and when this pressure is higher than a predetermined value, the transport is stopped via the air introduction means. In the air transport device, which prevents clogging of powdery material in the transport pipe by introducing compressed air into the pipe, the air introduction means is composed of two annular members that are in close contact with each other, and each part of the transport pipe is The annular member is interposed and fixed so as to be aligned between the upstream transport pipe part and the downstream transport pipe part forming an annular member, and to form an annular slit between the end faces of these annular members. When compressed air is introduced into the sealed pressure tank and the transport pipe in order to completely discharge the granular material, the compressed air is always introduced into the transport pipe through the annular slit of the air introducing means. This is achieved by a pneumatic transport device characterized by the following.

[Effect]

During normal plug transportation, if the transport pipe is clogged with granular material, the pressure inside the pipe increases. This is detected by the pressure detection means. Based on this detection, compressed air is introduced into the transport pipe via the air introduction means and acts to loosen the particulate material that is about to become clogged. This prevents blockage.

When compressed air is introduced into the closed pressure tank to empty the closed pressure tank and the transport pipe, the particulate material is transported by air at high speed through the transport pipe in a loose powder state. At this time, compressed air is always introduced into the transport pipe through the annular slit of the air introduction means, so even if the powder material does not enter the recess or hollow part of the air introduction means, it will be ejected from the annular slit. It is blown away into the transport pipe by a high-flux air flow. Therefore, the air introduction means can always function normally, and blockage in the transportation pipe during normal plug transportation can be reliably prevented. Further, the pressure detection means provided in the air introduction means can always accurately detect the pressure within the transport pipe where it is installed.

〔Example〕

EMBODIMENT OF THE INVENTION Hereinafter, a pneumatic transportation device according to an embodiment of the present invention will be described with reference to the drawings.

In the figure, a pressure tank 1 consists of a main body 2 and a lid 3, and the opening of the main body 2 is hermetically covered by the lid 3. A duct 4 is integrally formed with the lid 3 and is connected to the discharge opening of the hopper 9 via a lower valve 5, an intermediate duct 6, an upper valve 7 and a flexible joint 8. The hopper 9 is supported on the ground via appropriate members.

A discharge port 10 formed at the lower part of the main body 2 of the pressure tank 1 is connected to a discharge duct 11, which is connected to an air knife device 12 and a flexible joint 1.
3 to a long transport pipe 14. The transport pipe 14 is rigid rather than flexible, but extends to the collection tank 17, and in place supports 15, 1
It is supported on the ground by 6. Collection tank 17
An air filter 18 is provided at the upper part of the air filter 18, and a valve 19 is provided at the discharge opening, and the valve 19 is opened and closed by an actuating device 20.

The pressure tank 1 is supported on the ground by a hinge 21 on one wall side, and supported on the ground by a load cell 22 on the other wall side. That is, the entire weight of the pressure tank 1 is measured by the load cell 22. The pressure tank 1 is suspended from the ground by flexible joints 8 and 13, and its total weight is distributed between the valves 5 and 7 and the ducts 4, 6, and 1.
1. It is designed to be weighed together with the air knife device 12 by a load cell 22. Since the weights of these and the main body 2 and lid 3 of the pressure tank 1 are known in advance, the weight of the granular material in the pressure tank 1 can be known from the output of the load cell 22.
In addition, a vibrator 2 is installed on the side wall of the pressure tank 1.
3 is attached, and even if the granular material forms a bridge in the pressure tank 1 due to this vibration, this will be broken and a good fluid state can always be maintained inside. .

Next, the piping system to the pressure tank 1 will be explained.

A pipe 25 is connected to the tank 24 as a source of compressed air.
Compressed air is supplied to the upper part of the pressure tank 1 via. A valve 28 is connected to the pipe 25, whereby the pressure supplied into the pressure tank 1 is adjusted to, for example, 0.5 to 0.6 atmospheres in gauge pressure. The air flow rate is approximately 5 m/sec. For this purpose, pipe 25
Further, a flow meter 26 and a pressure gauge 27 are connected to. Compressed air supplied to the upper part of the pressure tank 1 from the piping 25 presses the powder material in the pressure tank 1 downward as a whole.

Pipes 29, 32, and 36 further branch out from the pipe 25, and a solenoid valve 30 is connected to the pipe 29, from which compressed air is also supplied to the upper part of the pressure tank 1. When the granular material is transported by air, that is, when the particulate material is present above the lower limit level of the pressure tank 1, the electromagnetic valve 3
0 is closed and the valve 28 mentioned above is open. To empty the pressure tank 1, and transport pipe 1
When it is desired to completely discharge the granular material from 4, the solenoid valve 30 is opened, the above-mentioned valve 28 is closed, and at a higher pressure, for example 15-20 m/sec.
Compressed air is sent into the pressure tank 1 at a flow rate.

The branch pipe 32 is connected to the outlet section 10 of the pressure tank 1 via a valve 35. The compressed air blown in from this fluidizes the powder material present in the pressure tank 1, making it easy to discharge into the transport pipe 14. A flow meter 33 and a pressure gauge 34 are used to adjust the flow rate and pressure of the compressed air so that it is appropriately fluidized.

The branch pipe 36 has a valve 39 and a solenoid valve 40.
It is connected to the air knife device 12 via.
As is well known, the air knife device 12 functions to blow out compressed air from a narrow gap on the outer periphery of the tube to cut the powder material in this area with a knife. The electromagnetic valve 40 automatically repeats on and off to supply pulsed compressed air. Flow meter 37, pressure gauge 38
The pressure and flow rate of this compressed air are adjusted as appropriate.

The solenoid parts 44, 45, 31, 41 of the electromagnetic valves 5, 7, 30, 40 are connected to a control circuit 43, respectively.
is connected to the output terminal of Also load cell 2
The output terminal of No. 2 is connected to the input terminal of the control circuit 43.

A pressure gauge 42 is connected to the tank 24 to detect the pressure inside the tank 24, and compressed air is supplied to it from a compressor (not shown) so that the pressure is within a predetermined range. It is assumed that

As mentioned above, the transport pipe 14 extends from the flexible joint 13 to the collection tank 17, and pressure detectors 51, 52, 53 are installed at three locations.
An air inlet 70 with a detector 5 is provided.
1, 52, and 53, the pressure inside the corresponding pipe is detected. Compressed air is supplied from the compressed air tank 57 to the air introduction device 70 via piping 58, 59, 60 and electromagnetic valves 54, 55, 56, respectively. When the pressure detectors 51, 52, 53 detect a pressure higher than a predetermined value, they generate an excitation signal, which is sent to the electromagnetic valves 54, 5.
5, 56 solenoid parts 54a, 55a, 56a
are supplied to open them. The output terminals of the control circuit 43 are further connected to the solenoid parts 54a, 55a, and 56a.

FIG. 2 shows details of the air introducer 70, which will now be described.

As shown by the dotted line, the air introducer 70 is fixed between the flange portion 14a of the upstream transport pipe 14 and the flange portion 14a of the downstream transport pipe 14 by bolts or the like (not shown).

The air introducer 70 consists of two annular members 71, 72 whose central openings 71a, 72a are aligned with the holes 14a, 14b of the transport tube 14 and whose inner diameters are equal. A hole 71b to which a pressure detector 52 (representatively shown; the same applies to the other detectors 51 and 53) is formed in the peripheral wall of one of the annular members 71, and a compressed air supply hole 71c. A conduit P for sending compressed air is attached to the hole 71c. The annular member 71 has a stepped hole, and an annular space 80 is formed between this and the other annular member 72. This opens the central openings 71a, 72a of both annular members 71, 72 through an annular slit-shaped gap 81 between both end faces of both annular members 71, 72,
That is, it communicates with the inside of the hole 14b of the transport pipe 14. By passing through such a space, the flow velocity of the compressed air supplied from the hole 71c of the annular member 71 is further increased due to the nozzle effect, and the compressed air is introduced into the transport pipe 14 at a speed almost close to the speed of sound. Ru.

The present embodiment is configured as described above, and its operation will be explained next.

First, normal transportation conditions will be explained. Inside the pressure tank 1, granular material is stored at a level above the lower limit level. This is detected by the load cell 22. That is, the specific gravity of the granular material is measured in advance, and the material level is calculated within the control circuit 43 from this value and the detected material weight. From this result, it is determined that the granular material exists in the pressure tank 1 at a level higher than the lower limit level, and the solenoid parts 44, 45, 31
is not excited, but a pulsed current is passed through the solenoid section 41 of the electromagnetic valve 40. That is, the electromagnetic valve 40 is repeatedly opened and closed to supply pulsed compressed air to the air knife device.

On the other hand, compressed air is supplied to the upper part of the pressure tank 1 through a pipe 25 and a valve 28, and the granular material present in the pressure tank 1 is entirely pressed downward. On the other hand, compressed air is also supplied from the discharge port 10 to keep the powder material in a fluid state. The vibration of the vibrator 23 prevents the formation of bridges of the powdered material in the pressure tank 1, and provides a good and uniform flow state of the material. The tendency for material to adhere to the inner walls of the pressure tank 1 and create bridging is prevented.

From the pressure tank 1, the granular material is smoothly guided through the duct 11 into the air knife device 12. Here, the continuously supplied powder material is divided by intermittent compressed air as if it were cut with a knife.
As shown in the figure, it is transported in the transport pipe 14 in the form of a plug. 47 is a powder material, and 48 is air.
Note that there is a gap 81 inside the air introducer 70,
In plug transportation, powder and granule materials are transported almost entirely through space 8.
It never leaks to 0.

Particulate material is collected in the collection tank 17, and air is exhausted to the outside through a filter 18. The filter 18 prevents the powder material from leaking to the outside.

When the load cell 22 detects that the granular material in the pressure tank 1 has decreased and reached a predetermined lower limit level, the control circuit 43 generates a signal to alternately energize the solenoids 45 and 44 of the electromagnetic valves 5 and 7. .

That is, the upper electromagnetic valve 7 is opened and the powder material is discharged from the hopper 9 into the duct 6.
When a predetermined amount is discharged or for a predetermined time,
When discharged, the solenoid section 44 is demagnetized and the electromagnetic valve 7 is closed. Next, the solenoid portion 45 of the electromagnetic valve 5 is energized and opened, and the powder material in the duct 6 is discharged into the pressure tank 1. When the gas is discharged for a predetermined period of time or when the duct 6 becomes empty, the solenoid section 45 is demagnetized and the electromagnetic valve 5 is closed. Next, the upper electromagnetic valve 7 is opened by the excitation of the solenoid section 44, and the material is supplied from the hopper 9 into the duct 6.

As described above, the electromagnetic valves 5 and 7 are alternately opened and closed, and the granular material is replenished from the hopper 9 into the pressure tank 1 via the intermediate duct 6. Even during this replenishment, the pressure tank 1 is continuously connected to the transport pipe 14.
The material is supplied to the plug and transported by pulsed compressed air. Compressed air is continuously supplied to the upper part of the pressure tank 1 from a pipe 25.
By alternately opening and closing the electromagnetic valves 5 and 7 as described above, this compressed air is prevented from being discharged from the hopper 9 into the atmosphere as much as possible. In other words, pressure loss during replenishment is prevented as much as possible.

When the load cell 22 detects that the granular material in the pressure tank 1 has been supplied to a predetermined upper limit level, the alternate excitation of the electromagnetic valves 5 and 7 is stopped.
Both valves 5 and 7 are closed again.

Next, a case where the pressure tank 1 is emptied and the granular material is completely discharged from the transport pipe 14 will be explained.

In this case, a complete ejection button provided in the control circuit 43 is pressed even though it is not shown. Even if the load cell 22 detects that the granular material in the pressure tank 1 has reached the lower limit level, in this case, the electromagnetic valves 5 and 7 will not operate, and the solenoid parts 31 and 41 of the electromagnetic valves 30 and 40 will Excited and demagnetized. That is, the electromagnetic valve 30 opens and compressed air is introduced into the pressure tank 1 at a high pressure and flow rate. Further, the electromagnetic valve 40 is normally closed and the supply of pulsed compressed air is stopped.

The material in the pressure tank 1 is discharged into the transport pipe 14 by continuous high-pressure compressed air, and the material in the transport pipe 14 is discharged by the compressed air into the collection tank 17. Note that due to the vibration of the vibrator 23, the amount of material adhering to the inner wall of the pressure tank 1 is reduced as much as possible.

The powder material is transported in a suspended state within the transport pipe 14, but in this embodiment, the granular material is transported between
1 into the space 80 is almost impossible. That is, when the complete ejection button is pressed, the control circuit 43 releases solenoids 54a and 55.
A drive signal is supplied to a and 56a. As a result, the electromagnetic valves 54, 55, and 56 are opened, and compressed air is supplied from the compressed air tank 57 to the air introduction device 70 through the conduit P. Since this is introduced into the transport pipe 14 from the space 81 at a high speed close to the speed of sound, the powder material floating in the transport pipe 14 and transported at high speed is transported from the space 81 to the space 80 in the air introducing device 70. Even if you try to invade, you will be held down and will not be able to invade. This prevents the space 80 from being clogged with particulate material.

The granular material accumulated in the collecting tank 17 is supplied to the next process by opening the valve 19 by driving the actuating device 20.

In the above plug transportation, the case where the granular material flows smoothly through the transport pipe 14 has been explained, but the granular material may try to block somewhere in the transport pipe 14 for some reason. According to this embodiment, this can be prevented and smooth flow can be guaranteed at all times.

Generally, the particulate material tends to become clogged immediately before the bend of the transport pipe 14, but let us now assume that no blockage occurs at the location where the pressure detector 51 is installed.
Then, the pressure inside the pipe in this part increases, and when this exceeds a predetermined value, the pressure detector 51 generates an excitation signal, which is sent to the solenoid part 54 of the electromagnetic valve 54.
supply to a. As a result, the electromagnetic valve 54, which had been closed until now, is opened, and the pipe 58 is connected to the tank 57.
Compressed air is supplied to the pipe section where the pressure detector 51 is attached. The compressed air loosens the powdery material that was about to become clogged, and it is smoothly transferred to the downstream side again.
As a result, the pressure inside this pipe drops to below the predetermined value again, and the excitation signal of the pressure detector 51 disappears.
Solenoid valve 54 closes again.

The above is the air introduction device 7 equipped with the pressure detector 51.
Although a case has been described in which the particulate material is likely to blockage in the vicinity where pressure sensor 0 is provided, blockage is similarly prevented in locations where other pressure detectors 52 and 53 are provided.
Note that since the air introducer 70 is not clogged with powdery material, accurate pressure can always be detected by the pressure detector.

The embodiments of the present invention have been described above, but of course the present invention is not limited thereto, and various modifications can be made based on the technical idea of the present invention.

For example, in the above embodiment, the air introducer 70 is equipped with pressure detectors 51 to 53 at three locations on the transport pipe 14.
is provided, but it may be further increased. Alternatively, the number may be reduced to one location, for example. However, since there is a considerable time delay in the pressure propagation of the fluid, it is preferable to increase the number of air inlets 70 equipped with pressure detectors, and if intrusion does not occur at a certain point, it is recommended to immediately remove it. Can be canceled. Further, as described above, since the powder material tends to become clogged slightly upstream of the curved portion of the general transport pipe 14, it is desirable to provide the air introducer 70 equipped with a pressure detector at such a location as much as possible.

Further, the air introducing means is not limited to the one having the configuration shown in FIG. 2, and all known air introducing devices of this type can be used.

[Effects of the Invention] As described above, according to the pneumatic transport device of the present invention, the air introduction means is not clogged with particulate material, so clogging of the particulate material in the transport pipe is always prevented. We can always guarantee smooth transportation.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway side view of a pneumatic transport device according to an embodiment of the present invention, and FIG. 2 is an enlarged sectional view of the main part in FIG. 1. In the figure, 1...pressure tank, 14...
Transport pipe, 51-53...Pressure detector, 54-56
... Solenoid valve, 57 ... Compressed air tank, 70
... Air introducer, 71, 72 ... Annular member.

Claims (1)

[Claims] 1 By supplying compressed air in pulses to a transport pipe connected to a closed pressure tank, the powder material discharged from the closed pressure tank is transported along the transport pipe as a plug, and the transport pipe An air introduction means equipped with a pressure detection means is provided in at least one location of the pipe to detect the pressure inside the pipe at the location, and when this pressure is higher than a predetermined value, compressed air is introduced into the transport pipe via the air introduction means. In the pneumatic transport device, which prevents clogging of powdery material in the transport pipe by introducing air, the air introducing means is composed of two annular members that are in close contact with each other, and the upstream side forming each part of the transport pipe. The transport pipe section and the downstream transport pipe section are interposed and fixed so as to be aligned in phase and to form an annular slit between the end faces of these annular members, and the granular material is removed from the sealed pressure tank and the transport pipe. The compressed air is always introduced into the transport pipe through the annular slit of the air introduction means when compressed air is introduced into the closed pressure tank and the transport pipe in order to completely discharge the compressed air. pneumatic transport equipment.