JP2004131189A - Pneumatic transport method and device for powder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To pneumatically and continuously transport powder in high vacuum/high density transportation mode by operating two batch type suction type pneumatic transport machines alternately. <P>SOLUTION: A pneumatic transport device is constituted in such a way that the transport machine 26 is first operated in high vacuum suction mode and the transport machine is put in a powder discharge process. In this device, a flap valve 62 of the transport machine is switched to "open" at the timing before the transport machine becomes full with powder to shift to simultaneous operation of both transport machines while maintaining plug transport or columnlike transport mode, then suction of the transport machine is stopped, and the flap valve 62 is closed to shut high vacuum in a suction chamber 52. Next, a back wash mechanism 74 of the transport machine is operated, and air pulses are discharged toward a bag filter 72 under high vacuum to effectively back-wash the bag filter by utilizing a difference in high pressure inside and outside the filter. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for continuously pneumatically transporting powder using two batch-type suction pneumatic transporters (also called vacuum conveyors) that are operated alternately. The present invention relates to a method for pneumatically conveying powder with high efficiency in a high vacuum and high concentration transportation mode called “plug transportation” or “columnar transportation” in the field. The present invention also relates to a batch suction air transport machine used for carrying out such a pneumatic transport method. The present invention further relates to a method for pneumatically transporting powder while effectively backwashing a dustproof filter of this type of pneumatic transporter.
[0002]
[Prior art]
The pneumatic transportation of powder can be broadly divided into a pumping type in which powder is pumped from behind by an air flow and a suction type in which vacuum is sucked from the front. The latter suction-type pneumatic transportation is considered to be more desirable because it has the advantage that dust does not leak even if damage such as cracks occurs in the piping path.
[0003]
The suction type pneumatic transport is performed using a suction type pneumatic transport machine (vacuum conveyor).
Suction type pneumatic transportation can be divided into batch type and continuous type according to the transport mode, and the configuration of the suction type pneumatic transport machine used is slightly depending on whether the transport mode is batch type or continuous type Different.
[0004]
Continuous suction air transportation is performed using a suction air transportation machine of a type that does not include a discharge damper mechanism that opens and closes the lower portion of the main body. This type of pneumatic transporter is directly installed on a sealed transport destination container, and has an advantage that powder can be sucked and transported continuously without interruption. However, since the powder transport destination container must be sealed, as a cutting device for quantitatively supplying powder from the transport destination container, a sealed type that can hold the vacuum of the transport destination container such as a rotary valve However, there is a difficulty that a cutting device must be used.
[0005]
On the other hand, batch-type suction pneumatic transportation is performed using a suction-type pneumatic transportation machine of a type having a discharge damper mechanism in the lower part. This type of pneumatic transporter equipped with a discharge damper mechanism can keep the suction chamber in a vacuum by sealing the lower part of the main body of the transporter with a discharge damper during pneumatic transportation. This has the advantage that it can be placed and therefore does not require a sealed cutting device such as a rotary valve.
The present invention relates to a suction-type pneumatic transport device (referred to as a batch-type suction-type pneumatic transport device) of the type provided with the discharge damper mechanism and a pneumatic transport method using the same.
[0006]
In batch-type suction-type pneumatic transportation, the discharge damper is closed and the suction chamber is sealed, and then the powder is sucked into the suction chamber of the main body, and when the suction chamber is filled with the sucked powder, suction is stopped, Next, the discharge damper is opened to discharge the powder to the transport destination container, and a series of operations are repeated for each batch.
[0007]
The disadvantage of batch suction pneumatic transportation is that, since suction transportation is performed only intermittently for each batch, the transportation efficiency is halved or lower than that of the continuous system.
Therefore, in the prior art, the powder is continuously pneumatically transported by using two batch suction air transporters and operating them alternately. Hereinafter, for convenience, this pneumatic transportation method is referred to as a “twin conveyor method”.
In the twin conveyor system, as shown in FIG. 1, two batch type suction type air transporters 2 are installed on the transport destination container 1, and the suction pipe 3 of each transporter 2 is connected via the branch pipe 4. Are connected to a common transport pipe 5 and the upstream end of the transport pipe 5 is connected to a first container 7 containing powder to be transported.
A shutoff valve 9 is arranged in each pipe line 8 between each suction pipe 3 and the branch pipe 4, and by switching these two shutoff valves 9 alternately, the two air transporters 2 are operated alternately. It is supposed to let you.
[0008]
In the conventional twin conveyor system, a pinch valve as shown in FIG. 2 is used as the shutoff valve 9 for opening and closing the pipe line 8.
The pinch valve 9 includes a rubber sleeve 10 and a pressure chamber 11 formed around the rubber sleeve 10, and the compressed air is sent from the compressed air inlet 12 to the pressure chamber 11, so that the rubber sleeve 10 is narrowed. FIG. The internal passage 13 is closed as shown in FIG.
When the application of compressed air to the pressure chamber 11 is released, the rubber sleeve 10 is restored by its elasticity and returns to the cylindrical shape shown in FIG.
This kind of pinch valve is used as the shutoff valve for the pipe line 8 because the inner diameter of the internal passage 13 becomes equal to the inner diameter of the front and rear pipe lines 8 in the fully opened state, and thus the obstacle and resistance to the transported powder. This is because there is an advantage that there is no longer.
[0009]
[Problems to be solved by the invention]
However, several problems are associated with pinch valves. The first problem is that even if the application of compressed air to the pressure chamber 11 is released, the pinch valve does not open at all as long as the vacuum is applied to the internal passage 13, or the valve opening response is very high. It is slow.
The reason for this is that the pinch valve opens when the rubber sleeve 10 is restored to its original cylindrical shape by its own elastic restoring force, so that the pressure in the pressure chamber 11 becomes atmospheric pressure by stopping the supply of compressed air. However, a vacuum exists in the passage inside the rubber sleeve 10, and the rubber sleeve 10 expands in diameter while the force that pulls the rubber sleeve 10 radially inward by the action of the vacuum overcomes the elastic restoring force of the rubber. This is because there is no, and it remains in the closed state as shown in FIG.
[0010]
Therefore, when switching between the two pneumatic transport machines, the rubber sleeve is temporarily broken by reducing the vacuum in the transport pipe 5 by temporarily stopping the vacuum pump of the pneumatic transport machine or the like. 10 must help restore.
When the vacuum break is caused in the transport pipe temporarily or the vacuum degree is lowered in this way, the negative pressure in the transport pipe takes a momentary breath, and the flow of the powder-air mixture in the transport pipe temporarily Stop. As a result, the powder may stall and drop in the vertical pipe 5A (FIG. 1) of the transport pipe 5 and accumulate on the bottom thereof, thereby closing the vertical pipe.
In addition, there is necessarily a certain delay before the high vacuum is restored in the pipe again after the vacuum in the transport pipe is temporarily broken, so high vacuum and high concentration transport in the form of plug transport or column transport is prescribed. As a result, the transport capacity of the entire twin conveyor system is reduced.
[0011]
Another problem of the pinch valve is that the rubber sleeve 10 is severely damaged and worn, so that the life of the rubber sleeve is shortened and the wear powder of the rubber sleeve is mixed into the powder to be transported and contaminates the powder. That is. The rubber sleeve is severely damaged and worn because the rubber sleeve is ground when the powder collides with the rubber sleeve in the half-open state. As a result, the rubber sleeve is quickly opened and needs to be replaced.
Still another problem of the pinch valve is that the restoring force of the rubber sleeve 10 is affected by the pressure in the pipe, so the switching operation and timing are unstable and uncertain, the response is slow and a time lag occurs, so the switching is accurately controlled. It is difficult to do.
[0012]
Instead of using the pinch valve 9, a ball valve type or sliding valve type three-way valve is arranged at the branch portion 4 of the transport pipe 5, and two batch-type suction pneumatic transports are switched by switching the three-way valve. It is also possible to operate the machine 2 alternately.
However, due to the structure of the ball valve or sliding valve of the three-way valve, the two outlets of the three-way valve are temporarily fully closed at the time of switching, and the vacuum break in the transport pipe 5 still occurs. As in the case of the pinch valve described above, there is a problem in that the vertical pipe is blocked by the powder that has stalled and dropped in the vertical pipe 5A of the transport pipe 5, and the transport capability is lowered.
Further, the three-way valve ball valve and the sliding valve are worn early due to the biting of the powder, and the smooth rotation thereof is hindered. Furthermore, since the ball valve and the sliding valve are switched by a rotational motion, there is a problem that the opening / closing speed is slow.
[0013]
The object of the present invention is to eliminate or minimize the vacuum break (so-called breathing) in the transport pipeline when switching between two pneumatic transporters when the powder is pneumatically transported by the twin conveyor system. Another object of the present invention is to provide an air transportation method capable of substantially maintaining a high vacuum / high concentration transportation mode from plug transportation to columnar transportation even when the air transportation equipment is switched, and an air transportation equipment used in the method.
[0014]
Another object of the present invention is to provide a twin conveyor type highly efficient pneumatic transportation method that is comparable to continuous suction type pneumatic transportation in terms of transportation capacity, and an air transportation machine used in the method.
Another object of the present invention is to provide an air transportation method in which a transport pipe is not clogged with powder when a pneumatic transport machine is switched when a powder is pneumatically transported by a twin conveyor system, and an air transport machine used in the method. There is to do.
[0015]
In the air transportation suction process, the air discharged from the suction chamber of the transport machine is filtered by a dustproof filter, and in the powder discharge process by opening the discharge damper, a compressed air pulse is injected inside the filter by the backwashing mechanism. Thus, the filter is backwashed (hereinafter also referred to as backwashing for short).
Another object of the present invention is to provide a method of pneumatically transporting powder while effectively backwashing the dustproof filter of a batch suction type air transporter, regardless of whether it is a twin conveyor system or a single system. There is to do.
[0016]
[Means for Solving the Problems]
In the pneumatic transportation by the twin conveyor system of the present invention, two batch suction air transportation machines are used.
Each batch-type suction pneumatic transporter includes a body defining a sealable suction chamber, the body having an inner end (inner and outer terms refer to a positional relationship about the axis of the body) Comprises a suction pipe extending into the suction chamber and having an air transport pipe connected to the outer end thereof, an air outlet connected to a vacuum source, and a discharge damper mechanism for discharging powder in the suction chamber at a predetermined timing. Yes.
Each pneumatic transporter is further disposed in the suction chamber of the main body, and is disposed in the suction chamber on the upstream side of the outlet, with a power-driven flap valve mechanism that controls opening and closing of the opening at the inner end of the suction pipe. A filter for filtering the air flowing out from the chamber to the outlet, and a backwashing mechanism for backwashing the filter by injecting a compressed air pulse inside the filter at a predetermined timing. And a shutoff valve connected between the outlet and the vacuum source and configured to shut off a vacuum applied from the vacuum source to the suction chamber.
[0017]
One feature of the pneumatic transport device of the present invention is that a power-driven flap valve mechanism is used to control opening and closing of the suction pipe.
In a preferred embodiment, the power-driven flap valve mechanism is an air-driven flap valve mechanism and has an air actuator that swings the flap valve body.
Unlike prior art pinch valves, power driven flap valves can be reliably opened even under high vacuum, so there is no need to vacuum break the transport line for switching. Therefore, the two pneumatic transporters can be switched while maintaining the high vacuum / high concentration transport mode.
Further, since the power-driven flap valve mechanism is disposed in the suction chamber of the transport machine body, the piping operation is greatly simplified.
Unlike the pinch valve, the flap valve mechanism does not remain in a half-open state, and therefore has an advantage that it is not subjected to grinding action by the colliding powder and is not worn.
[0018]
When pneumatically transporting powder from the first container to the second container,
(1) The first and second batch suction air transporters are arranged on the second container, and the outer end of the suction pipe of each air transporter is attached to the first container. Connected to the suction pipe of the air through the pneumatic transport pipe, and the shut-off valve of each pneumatic transport machine is connected to a high vacuum source such as an ejector or a blower through the vacuum pipe,
(2) The shut-off valve of the first air transporter with the shut-off valve of the second air transporter closed, the flap valve closed, the discharge damper opened, and the discharge damper of the first air transporter closed. And by opening the flap valve, the powder is pneumatically transported from the first container into the suction chamber of the first pneumatic transporter over a predetermined time,
(3) Next, the conduit is substantially closed while the first air transporter is operated under high vacuum by closing the discharge damper of the first air transporter, opening the shut-off valve, and keeping the flap valve open. By closing the discharge damper of the second air transporter, opening the shut-off valve, and opening the flap valve without breaking the vacuum, both the first air transporter and the second air transporter are simultaneously high vacuum. (Simultaneous operation on both sides).
Since the flap valve mechanism that opens even under high vacuum is used, at this stage, the flap valve can be switched to open while maintaining a high vacuum without breaking the vacuum inside the pneumatic transport pipe. As a result, the air flow in the high vacuum / high concentration transport mode in the state of plug transport or column transport is maintained in the air transport pipe during the simultaneous operation transition.
[0019]
(4) Next, while continuing the operation of the second pneumatic transport device, the suction valve of the first pneumatic transport device is switched by closing the shut-off valve of the first pneumatic transport device, closing the flap valve, and opening the discharge damper. Stop the air transport to and discharge the powder in the suction chamber to the second container,
(5) Next, the duct is substantially closed while the second air transporter is operated under high vacuum by closing the discharge damper of the second air transporter, opening the shut-off valve and keeping the flap valve open. The vacuum damper of the first air transporter is closed, the shutoff valve is opened, and the flap valve is switched to open without breaking the vacuum of the first air transporter. And move to simultaneous operation on both sides. Pneumatic transportation is performed by repeating the steps (2) to (5) as necessary.
[0020]
According to the method of the present invention, a high concentration transport mode can be secured by applying as high a vacuum as possible in the transport pipe, and this high vacuum is substantially maintained even during the transition to simultaneous operation. The transportation efficiency of transportation is significantly improved.
According to the method of the present invention, the transportation capacity is about 4 times or more (4 to 6 tons) compared to the case of switching between two pneumatic transporters while breaking the vacuum in the transportation pipe (for example, 1 ton / hour). / Hour).
[0021]
Preferably, the pneumatic transport steps (2) and (4) are performed under a high vacuum stronger than an average of about -30 kPa, more preferably under a high vacuum stronger than an average of about -50 kPa.
[0022]
In a preferred embodiment of pneumatic transportation by twin conveyor system,
(1) The first and second batch type suction air transporters according to any one of claims 1 to 3 are arranged on the second container, and the outer ends of the suction pipes of the respective air transporters are arranged. Connect to a common suction pipe from the first container via an air transport pipe, and connect the shut-off valve of each air transport machine to a vacuum source via a vacuum pipe,
(2) With the shut-off valve of the second air transporter closed, the discharge damper opened, and the discharge damper of the first air transporter closed, the shut-off valve and flap valve of the first air transporter opened. Thus, the powder is pneumatically transported from the first container into the suction chamber of the first pneumatic transporter over a predetermined time,
(3) Next, with the discharge damper of the first air transporter closed, the shutoff valve opened, and the flap valve opened, the exhaust air damper of the second air transporter closed, the shutoff valve opened, and the flap valve Switching to open and applying vacuum to the suction chambers of both the first and second pneumatic transporters to operate both the first and second pneumatic transports simultaneously;
(4) Next, with the discharge damper of the first air transporter closed and the flap valve opened, the shut-off valve of the first air transporter is switched to the closed state to the suction chamber of the first air transporter. While the air transport of the second air transporter is stopped, the vacuum in the suction chamber of the second air transporter is transmitted to the suction chamber of the first air transporter via the air transport pipe and reflected to reflect the vacuum in the suction chamber of the first air transporter. Maintain the vacuum,
(5) Next, a high vacuum is confined in the suction chamber of the first pneumatic transporter by closing the flap valve of the first pneumatic transporter.
[0023]
(6) With the high vacuum confined in the suction chamber of the first air transporter in this way, the backwashing mechanism of the first air transporter is then operated to compress the suction chamber under the high vacuum. The filter of the 1st air transport machine is backwashed by injecting an air pulse.
In this backwashing process, a compressed air pulse (positive pressure) is injected into the suction chamber maintained under high vacuum, so that the pressure difference (ΔP) between the inside and outside of the filter is high and backwashing is performed effectively. Is called.
[0024]
(7) Next, by opening the discharge damper of the first pneumatic transport device, the powder in the suction chamber of the first pneumatic transport device is discharged to the second container,
(8) Next, the steps (2) to (7) are executed while the relationship between the first pneumatic transporter and the second pneumatic transporter is reversed. The steps (2) to (8) are repeated as necessary.
[0025]
Preferably, in the backwashing step, the injection of the compressed air pulse is repeated until the pressure in the suction chamber of the pneumatic transporter becomes atmospheric pressure. In this way, when the pressure in the suction chamber recovers to atmospheric pressure, the discharge damper opens automatically by its own weight and the weight of the powder, and discharges the powder.
[0026]
The present invention also provides a method for pneumatically transporting powder while effectively back-washing the dustproof filter of a batch suction air transporter that is batch operated independently,
(1) A batch suction air transporter is placed on the second container, and the outer end of the suction pipe of the air transporter is connected to a common suction pipe from the first container via the air transport pipe. At the same time, connect the shutoff valve of the pneumatic transporter to the vacuum source via the vacuum pipe,
(2) With the discharge damper of the pneumatic transporter closed, by opening the shutoff valve and flap valve, the powder is pneumatically transported from the first container into the suction chamber of the pneumatic transporter over a predetermined time period.
(3) Next, the suction of the powder into the suction chamber is stopped by closing the flap valve, and a high vacuum is maintained in the suction chamber by continuing to apply the vacuum of the vacuum source to the suction chamber.
(4) Next, a high vacuum is closed in the suction chamber by closing the shut-off valve,
(5) Next, the backwashing mechanism is operated to inject the compressed air pulse into the suction chamber under high vacuum, thereby backwashing the filter.
(6) Next, the powder in the suction chamber is discharged to the second container by opening the discharge damper,
(7) The steps (2) to (6) are repeated. The jet of compressed air pulses can be repeated until the pressure in the suction chamber reaches atmospheric pressure.
[0027]
Since the backwashing step (5) is performed in a state where a high vacuum is confined in the suction chamber of the pneumatic transporter, the pressure difference (ΔP) between the inside and outside of the filter is high and backwashing is performed effectively.
The above-described features and effects of the present invention as well as other features and effects will be further clarified as the following examples are described.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
With reference to the accompanying drawings, embodiments of the pneumatic transportation method of the present invention, the pneumatic transportation system for carrying out the method, and the pneumatic transportation machine used in the system will be described.
Referring to FIG. 3 conceptually showing the entire pneumatic transportation system, this pneumatic transportation system transfers powder 22 contained in one or a plurality of containers (first containers) 20 to another container (second container) 24. It is configured for pneumatic transportation. The first container 20 and the second container 24 can be any container, and as a non-limiting example, the first container 20 is a powder production tank disposed in a powder production plant, and the second container 24. Can be a hopper or other storage container with a powder cutting mechanism.
[0029]
This pneumatic transport system has two batch suction air transporters (vacuum conveyors) 26 according to the invention arranged on a second container 24. In the illustrated embodiment, each pneumatic transport device 26 is composed of an upper suction module 28 and a lower damper module 30, which are detachably coupled by an appropriate number of buckle devices 32.
The suction module 28 of each air transporter 26 includes a suction pipe 34 extending into the suction chamber, and the outer end of each suction pipe 34 is common air transport to the two air transporters 26 via the branch pipe 36. Connected to tube 38. The upstream end of the air transport pipe 38 can be connected to a suction nozzle 40 disposed in the first container 20. If the first container 20 comprises a hopper, the upstream end of the pneumatic transport tube 38 can be connected to the hopper outlet, for example, in the conventional manner shown in FIG.
[0030]
A shutoff valve 44 is provided on the upper cover 42 of the suction module 28 of each pneumatic transport device 26, and an outlet port of the shutoff valve 44 is connected to a vacuum source 48 via a vacuum pipe 46. As the vacuum source 48, a blower such as a Roots blower or a multistage ring blower, an ejector type vacuum pump, or another type of vacuum pump can be used.
The damper module 30 of each pneumatic transport device 26 includes a discharge damper mechanism, which will be described later with reference to FIG. 5, and the second powder 24 has a relationship such that the internal powder falls into the second container 24 when the discharge damper is opened. It is installed on the container 24.
[0031]
Referring to FIG. 4, the suction module 28 of each pneumatic transporter 26 includes a cylindrical main body 50 in which a suction chamber 52 is defined.
The suction pipe 34 penetrates through the main body 50 and projects into the suction chamber 52, and the inner end of the suction pipe 34 is opened and closed by an air driven flap valve mechanism 54.
The flap valve mechanism 54 is fixed to a bracket 56 fixed to the suction pipe 34 by welding or bolting, a 90-degree swinging air-driven rotary actuator 58 fixed to the bracket, and an output shaft of the actuator. The swing arm 60 and a flap valve body 62 attached to the swing arm can be used. The end face of the flap valve body 62 is covered with a rubber lining so that the inner end of the suction pipe 34 is sealed.
The air-driven rotary actuator 58 is driven by compressed air from a compressed air source 70 such as an air compressor, and the supply of compressed air is performed by a programmable control device 64 common to the two air transporters 26. Controlled by a controlled solenoid valve 66.
[0032]
An air outlet 68 is provided in the upper cover 42 of each suction module 28, and this air outlet is connected to the inlet port of the shut-off valve 44. In the illustrated embodiment, the shut-off valve 44 is of an air drive type, and the compressed air that drives the shut-off valve 44 is also controlled by an electromagnetic valve 66 that is controlled by a control device 64.
[0033]
4 and 6, in the suction chamber 52 of each suction module 28, a bag filter 72 for filtering the air flowing out from the suction chamber 52 to the outlet 68, and this is injected by compressed air pulses. A backwashing mechanism 74 for periodically backwashing the bag filter 72 is provided.
The bag filter 72 is supported by a frame 76 made of a perforated plate or the like attached to the upper lid 42 of the suction module 28.
The backwashing mechanism 74 is of a conventional type, and can be composed of, for example, a compressed air tank 78 supported by the upper lid 42 and an air cylinder device 80. The air cylinder device 80 includes a piston 82 mounted on the cylinder and a check valve 84. When the piston 82 descends, the compressed air from the compressed air hose 86 is filled in the compressed air tank 78, and as shown in FIG. When 82 rises, the inlet of the compressed air tank 78 is opened, and the compressed air in the compressed air tank 78 is jetted into the bag filter 72 as indicated by an arrow 88 to backwash the bag filter 72. ing.
Compressed air to the air cylinder device 80 is controlled by a solenoid valve 90 controlled by a control device 64.
[0034]
The powder sucked into the suction chamber 52 of the suction module 28 of each pneumatic transport device 26 falls into the damper module 30.
4 and 5, the damper module 30 is of a conventional type and
A discharge damper mechanism 94 for opening and closing the upper opening and the lower outlet opening thereof is provided.
As can be clearly seen from FIG. 5, the discharge damper mechanism 94 includes a discharge damper 96 that can seal the outlet opening of the hopper 92, a swing arm 98 with a roller for swinging the discharge damper 96 upward, An oscillating vane type aerodynamic actuator 100 for driving the arm 98 is provided. The gap between the hopper 92 and the discharge damper 96 is sealed by an elastomer seal ring 102. The actuator 100 is also controlled by the control device 64 via the electromagnetic valve 90.
[0035]
Next, the operation sequence of the pneumatic transportation system will be described. Any one of the two pneumatic transporters 26 is referred to as a first (# 1) transporter, and the other is referred to as a second (# 2) transporter.
The vacuum pump 48 and the air compressor 70 are operated, the shut-off valve 44 of the # 2 transport machine is closed, the flap valve 62 is closed, the discharge damper 96 is opened, and the discharge damper 96 of the # 1 transport machine is closed Then, the shut-off valve 44 and the flap valve 62 of the # 1 transport aircraft are opened. Thereby, the powder in the first container 20 is sucked into the suction chamber 52 of the # 1 transport machine via the suction nozzle 40 and the air transport pipe 38 (# 1 suction process, # 2 discharge process).
The suction of the powder is performed under high vacuum, which is called “plug transport” or “columnar transport”, and preferably under a vacuum higher than the average of about −30 kPa, more preferably about −50 kPa. Under a stronger vacuum.
The powder that has been pneumatically transported to the # 1 transport machine is accumulated in the damper module 30.
[0036]
When the powder is pneumatically transported to the # 1 transporter for a predetermined time (for example, 2 to several seconds), the discharge damper 96 of the # 1 transporter is closed and shut off at the timing before the damper module 30 is filled with powder. With the valve 44 opened and the flap valve 62 opened, the discharge damper 96 of the # 2 transport machine is closed, the shutoff valve 44 is opened, and the flap valve 62 is switched to open.
Unlike the pinch valve of the prior art, the flap valve 62 driven by the air driven rotary actuator 58 opens reliably and quickly even under high vacuum. Therefore, pneumatic transport is required to open the flap valve 62 of the # 2 transport aircraft. There is no need to vacuum break the tube 38.
By switching the flap valve 62 of the # 2 transporter to open, a vacuum is applied to the suction chambers 52 of both the # 1 transporter and the # 2 transporter, and both the # 1 transporter and the # 2 transporter are simultaneously The suction of powder from the first container 20 is started (both simultaneous operation).
Since the number of vacuum pumps 48 is one, the transport amount of each transport device is halved during simultaneous operation of both, but the flow rate of the entire transport pipe 38 and the flow rate of the suction nozzle 40 do not drop. Therefore, the advantages of high concentration transportation continue to be enjoyed.
Since the two transport machines 26 are operating simultaneously, a high vacuum is maintained in the transport pipe 38 and a high vacuum is maintained in the suction chambers 52 of both transport machines 26.
[0037]
Next, with the discharge damper 96 of the # 1 transporter closed and the flap valve 62 opened, the shut-off valve 44 of the # 1 transporter is switched to the closed state. When the shut-off valve 44 of the # 1 transport machine is closed, the air transport to the suction chamber of the # 1 transport machine stops and the inflow of powder from the suction pipe 34 stops (# 1 suction stop).
However, at this point, the # 2 transport machine is already operating, and the entire transport pipe 38 is still under a high vacuum as described above, so that the # 1 transport machine remains open with the flap valve 62 of the # 1 transport machine open. Even if the shutoff valve 44 is closed, the high vacuum in the transport pipe 38 is reflected in the suction chamber 52 of the # 1 transport aircraft, and the suction chamber 52 of the # 1 transport aircraft is maintained under a high vacuum.
[0038]
Next, when the powder flow from the suction pipe 34 of the # 1 transport machine to the suction chamber 52 stops, the flap valve 62 of the # 1 transport machine is closed. Since the flow of the powder is stopped, the powder does not bite between the flap valve 62 and the inner end of the suction pipe 34, and sealing failure of the flap valve 62 due to the biting of the powder is prevented.
Thus, a high vacuum is confined in the suction chamber 52 of the # 1 transport machine.
[0039]
With the high vacuum confined in the suction chamber 52 of the # 1 transport machine in this way, the backwash mechanism 74 of the # 1 transport machine is then operated to quickly release the compressed air in the compressed air tank 78. . The compressed air ejected from the compressed air tank 78 is jetted into the bag filter 72 as an air pulse, and the bag filter 72 is backwashed (# 1 backwashing).
Since the air pulse is emitted toward the suction chamber 52 under high vacuum, the pressure difference (ΔP) inside and outside the bag filter 72 is high. Therefore, the backwashing of the bag filter is performed very effectively.
[0040]
The shut-off valve 44 is provided on the upper cover 42 of the suction module 28, the volume of the space between the bag filter 72 and the shut-off valve 44 is minimized, and the rear (downstream side) of the backwash mechanism 74. Therefore, the air pulse emitted from the compressed air tank 78 effectively acts on the bag filter 72 without waste and effectively backwashes it.
The air pulse can be emitted a plurality of times (for example, five times). Each time an air pulse is emitted, the pressure in the suction chamber 52 of the # 1 transporter gradually approaches atmospheric pressure.
[0041]
When the pressure in the suction chamber 52 of the # 1 transporter approaches atmospheric pressure, the discharge damper 96 automatically opens due to its own weight and the weight of the powder and discharges the powder to the second container 24 (# 1 discharge) ).
[0042]
When powder suction, filter backwashing, and powder discharge are completed for the # 1 transport machine, the same operation is performed for the # 2 transport machine, and further, a series of these operations are performed to transport a desired amount of powder. Repeat as necessary.
Thus, according to the present invention, the two pneumatic transporters 26 can be operated alternately without substantially breaking the vacuum in the transport pipe 38 and thus maintaining the plug transport or the column transport. As a result, the transport capacity is greatly increased (about 4 times or more) compared to the conventional method.
[0043]
Although the twin conveyor type pneumatic transport has been described above, the method of the present invention can also be applied to a pneumatic transport system using a single batch suction air transporter.
In this case, in the system configuration shown in FIG. 3, one of the pneumatic transporters is omitted.
The sequence of operation of this pneumatic transport system can be as follows.
[0044]
-Pneumatically transport powder from the first container 20 into the suction chamber 52 of the pneumatic transporter over a predetermined time by opening the shutoff valve 44 and flap valve 62 with the exhaust damper 96 of the pneumatic transporter closed. .
-Next, the suction of the powder into the suction chamber 52 is stopped by closing the flap valve 62 and a high vacuum is maintained in the suction chamber 52 by continuing to apply the vacuum of the vacuum source 48 to the suction chamber.
Next, a high vacuum is confined in the suction chamber 52 by closing the shut-off valve 44.
-Next, the backwashing mechanism 74 is activated to jet the compressed air pulse into the suction chamber 52 under high vacuum, thereby washing the filter 72 backwashing.
-The powder is then discharged into the second container 24 by opening the discharge damper 96.
-Repeat the above operation.
[0045]
Even in this air transport system using a single air transporter, the air pulse is emitted toward the suction chamber 52 under high vacuum in the backwash process, so that the pressure difference (ΔP) inside and outside the bag filter 72 is reduced. The back filter is effectively washed back.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram of a conventional twin conveyor type pneumatic transportation system.
2 is a cross-sectional view of a pinch valve used in the conventional system shown in FIG. 1, in which (A) shows a fully open position and (B) shows a fully closed position.
FIG. 3 is a conceptual diagram of a twin conveyor type pneumatic transportation system of the present invention.
4 is a partially cutaway schematic view of one pneumatic transport device and its control device of the system shown in FIG. 3, in which the compressed air system is indicated by a solid line, and the electrical signal system is indicated by a broken line.
FIGS. 5A and 5B show a discharge damper mechanism of the pneumatic transport device shown in FIG. 4, in which FIG. 5A is a perspective view and FIG. 5B is a side view.
6 is a cross-sectional view of a filter and a backwashing mechanism provided on the upper cover of the suction module of the pneumatic transport device shown in FIG. 4;
[Explanation of symbols]
26: Batch suction air transporter
34: Suction pipe
38: Pneumatic transport pipe
44: Shut-off valve
48: Vacuum source
50: Main body of transport aircraft
52: Suction chamber
54: Flap valve mechanism
68: Air outlet of the body
72: Filter
74: Backwash mechanism
94: Discharge damper mechanism

Claims (12)

A main body defining a suction chamber, wherein an inner end extends into the suction chamber and an air transport tube is connected to the outer end, an air outlet connected to a vacuum source, and powder in the suction chamber A main body equipped with a discharge damper mechanism that discharges at a predetermined timing;
A power-driven flap valve mechanism that is disposed in the suction chamber of the main body and controls opening and closing of the opening of the inner end of the suction pipe;
A filter disposed in the suction chamber upstream of the outlet, for filtering air flowing out from the suction chamber to the outlet;
A backwashing mechanism that is disposed inside the filter and injects a compressed air pulse inside the filter at a predetermined timing to backwash the filter;
A shutoff valve that is connected between the outlet and a vacuum source and shuts off a vacuum applied from the vacuum source to the suction chamber;
And a batch suction air transport machine. 2. The pneumatic transport device according to claim 1, wherein the power-driven flap valve mechanism is an air-driven flap valve mechanism and has an air actuator that swings a flap valve body. 3. An air transporter according to claim 1 or 2, wherein the shut-off valve is arranged in the upper part of the main body in the vicinity of the air outlet in order to minimize the volume of the space between the filter and the shut-off valve. In continuous pneumatic transportation to the second container using two batch suction air transport machines that alternately operate the powder contained in the first container,
(1) The first and second batch type suction air transporters according to any one of claims 1 to 3 are arranged on the second container, and the outer ends of the suction pipes of the respective air transporters are arranged. Connect to a common suction pipe from the first container via an air transport pipe, and connect the shut-off valve of each air transport machine to a high vacuum source via a vacuum pipe,
(2) The shut-off valve of the first air transporter with the shut-off valve of the second air transporter closed, the flap valve closed, the discharge damper opened, and the discharge damper of the first air transporter closed. And by opening the flap valve, the powder is pneumatically transported from the first container into the suction chamber of the first pneumatic transporter over a predetermined time,
(3) Next, the conduit is substantially closed while the first air transporter is operated under high vacuum by closing the discharge damper of the first air transporter, opening the shut-off valve, and keeping the flap valve open. By closing the discharge damper of the second air transporter, opening the shut-off valve, and opening the flap valve without breaking the vacuum, both the first air transporter and the second air transporter are simultaneously high vacuum. Operated with
(4) Next, while continuing the operation of the second pneumatic transport device, the suction valve of the first pneumatic transport device is switched by closing the shut-off valve of the first pneumatic transport device, closing the flap valve, and opening the discharge damper. Stop the air transport to and discharge the powder in the suction chamber to the second container,
(5) Next, the duct is substantially closed while the second air transporter is operated under high vacuum by closing the discharge damper of the second air transporter, opening the shut-off valve and keeping the flap valve open. The vacuum damper of the first air transporter is closed, the shutoff valve is opened, and the flap valve is switched to open without breaking the vacuum of the first air transporter. Operated with
(6) A pneumatic transportation method characterized by repeating the steps (2) to (5) as necessary. 5. The pneumatic transportation method according to claim 4, wherein the pneumatic transportation process is performed under a high vacuum that enables plug transportation or columnar transportation of powder. 6. The pneumatic transportation method according to claim 5, wherein the pneumatic transportation step is performed under a high vacuum stronger than an average of about -30 kPa. In continuous pneumatic transportation to the second container using two batch suction air transport machines that alternately operate the powder contained in the first container,
(1) The first and second batch type suction air transporters according to any one of claims 1 to 3 are arranged on the second container, and the outer ends of the suction pipes of the respective air transporters are arranged. Connect to a common suction pipe from the first container via an air transport pipe, and connect the shut-off valve of each air transport machine to a vacuum source via a vacuum pipe,
(2) With the shut-off valve of the second air transporter closed, the discharge damper opened, and the discharge damper of the first air transporter closed, the shut-off valve and flap valve of the first air transporter opened. Thus, the powder is pneumatically transported from the first container into the suction chamber of the first pneumatic transporter over a predetermined time,
(3) Next, with the discharge damper of the first air transporter closed, the shutoff valve opened, and the flap valve opened, the exhaust air damper of the second air transporter closed, the shutoff valve opened, and the flap valve Switching to open and applying vacuum to the suction chambers of both the first and second pneumatic transporters to operate both the first and second pneumatic transports simultaneously;
(4) Next, with the discharge damper of the first air transporter closed and the flap valve opened, the shut-off valve of the first air transporter is switched to the closed state to the suction chamber of the first air transporter. While the air transport of the second air transporter is stopped, the vacuum in the suction chamber of the second air transporter is transmitted to the suction chamber of the first air transporter via the air transport pipe and reflected to reflect the vacuum in the suction chamber of the first air transporter. Maintain the vacuum,
(5) Next, a high vacuum is confined in the suction chamber of the first pneumatic transporter by closing the flap valve of the first pneumatic transporter,
(6) Next, the backwashing mechanism of the first air transporter is operated to inject the compressed air pulse into the suction chamber under high vacuum, thereby backwashing the filter of the first air transporter,
(7) Next, by opening the discharge damper of the first pneumatic transport device, the powder in the suction chamber of the first pneumatic transport device is discharged to the second container,
(8) Next, the steps (2) to (7) are executed while reversing the relationship between the first pneumatic transporter and the second pneumatic transporter.
(9) A pneumatic transportation method characterized by repeating the steps (2) to (8) as necessary. 8. The pneumatic transportation method according to claim 7, wherein the pneumatic transportation step is performed under a high vacuum that enables plug transportation or columnar transportation of powder. 9. The pneumatic transportation method according to claim 8, wherein the pneumatic transportation step is performed under a high vacuum stronger than an average of about -30 kPa. 10. The pneumatic transport method according to claim 7, wherein the jet of compressed air pulses is repeated in the backwashing step until the pressure in the suction chamber of the pneumatic transporter reaches atmospheric pressure. When pneumatically transporting the powder contained in the first container to the second container using the batch suction air transporter based on any one of claims 1 to 3,
(1) The batch suction air transporter is disposed on the second container, and the outer end of the suction pipe of the air transporter is connected to the common suction pipe from the first container through the air transport pipe. Connect the shut-off valve of the pneumatic transporter to the vacuum source via the vacuum pipe,
(2) With the discharge damper of the pneumatic transporter closed, by opening the shutoff valve and flap valve, the powder is pneumatically transported from the first container into the suction chamber of the pneumatic transporter over a predetermined time period.
(3) Next, the suction of the powder into the suction chamber is stopped by closing the flap valve, and a high vacuum is maintained in the suction chamber by continuing to apply the vacuum of the vacuum source to the suction chamber.
(4) Next, a high vacuum is closed in the suction chamber by closing the shut-off valve,
(5) Next, the backwashing mechanism is operated to inject the compressed air pulse into the suction chamber under high vacuum, thereby backwashing the filter.
(6) Next, the powder in the suction chamber is discharged to the second container by opening the discharge damper,
(7) A pneumatic transportation method characterized by repeating the steps (2) to (6). 12. The pneumatic transportation method according to claim 11, wherein the jet of compressed air pulses is repeated until the pressure in the suction chamber reaches atmospheric pressure in the backwashing step.

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