JP4544449B2 - Suction-type powder transport method and apparatus using spiral airflow - Google Patents

Description

  The present invention relates to a method and apparatus for pneumatically transporting a granular material using a conduit, and more particularly to a suction-type pneumatic transportation method and apparatus using a spiral airflow.

The pneumatic transportation of powder using a conduit can be broadly divided into a pressure-feeding type in which powder is pumped from behind by a pressure air flow and a suction type in which powder is sucked from the front using vacuum.
In the prior art, a pneumatic transportation method and apparatus using a spiral air flow, whether suction type or pressure feeding type, has been proposed.
Japanese Patent Application Laid-Open No. 10-181883 and Japanese Patent Application Laid-Open No. 11-199049 disclose a suction-type pneumatic transport device using a vortex. In this apparatus, a vortex generating unit having a slit intersecting with the air suction direction in the transport pipe is provided at the end of the transport pipe, and a spiral and low-speed air flow is generated in the transport pipe. Yes. In this apparatus, since the eddy current generating unit must be provided at the end of the transport pipe, there is a problem that a booster for maintaining the eddy current cannot be provided in the middle of the transport pipe. Japanese Patent Application Laid-Open Nos. 60-31437 and 62-58100 disclose a pneumatic feeding method using a helical airflow. In this transportation method, an ejector utilizing the Coanda effect is provided at the upstream end of the transportation pipe. It is described that when a pressure fluid is supplied to the ejector, a spiral air flow similar to a tornado is generated in the transport pipe, and the solid particles are transported without contacting the inner wall of the transport pipe. Since this transport method is a pressure-feed type that supplies the pressure fluid ejected from the ejector to the upstream end of the transport pipe, it is considered that a high-vacuum tornado-like air flow will not occur along the axis of the transport pipe. .

An object of the present invention is to improve a suction type powder transportation method and apparatus using a spiral air flow.
Another object of the present invention is to provide a suction-type powder transport method and apparatus using a spiral air flow in which the powder does not contact the inner wall of the transport pipe.
Another object of the present invention is to provide a suction powder transport method and apparatus capable of maintaining a spiral airflow.
Another object of the present invention is to provide a helical airflow generator and a booster device that can be suitably used for suction-type powder transportation.

  The present invention provides a suction-type powder transport method for transporting powder by suction from a powder source to a powder transport destination container via a transport pipe, and this method is performed at the upstream end of the transport pipe. A secondary gas flow that supplies powder to the central portion in the radial direction of the transport pipe, supplies secondary gas to the radially outer side of the central portion and near the inner peripheral wall of the transport pipe, and flows into the upstream end of the transport pipe Is spirally turned along the inner circumference of the transport pipe to generate a spiral air flow in the transport pipe.

  In another aspect, the present invention provides a suction-type powder transport apparatus using a spiral airflow, which includes a transport pipe disposed between a powder source and a powder transport destination container, A suction means for sucking the downstream end of the transport pipe to transport the powder from the powder source to the powder transport destination container via the transport pipe, and a powder supply pipe opening in the center of the upstream end of the transport pipe; And transporting the secondary gas flow flowing into the transport pipe from the secondary gas inlet formed between the powder supply pipe and the inner peripheral wall of the transport pipe at the upstream end of the transport pipe by applying a circumferential velocity to the transport pipe. And a spiral airflow generation device for generating a spiral airflow in the pipe.

  In yet another aspect, the present invention provides a spiral airflow generator for use in suction-type powder transport by a spiral airflow, which comprises a small diameter outlet for connecting a large diameter inlet and a powder transport pipe. A housing having a pipe, a conical portion connecting the large diameter inlet and the small diameter outlet pipe, a powder supply pipe arranged concentrically inside the large diameter inlet, the large diameter inlet and the powder supply An impeller rotatably disposed in an annular gap between the pipe and driving means for rotationally driving the impeller is provided.

  In still another aspect, the present invention provides a spiral airflow booster device that is inserted in the middle of a powder transport tube in order to sustain or enhance the spiral airflow in suction type powder transportation by a spiral airflow. A large-diameter inlet adapted to receive the upstream powder transport pipe, a small-diameter outlet pipe for connecting the downstream powder transport pipe, and a conical portion connecting the large-diameter inlet and the small-diameter outlet pipe. A housing provided with, an impeller rotatably disposed in an annular gap between the large-diameter inlet and the upstream powder transport pipe, and drive means for rotationally driving the impeller. It is what.

According to the powder transport method and apparatus of the present invention, a relatively low-vacuum spiral airflow is formed along the inner peripheral wall of the transport tube, and a relatively high-vacuum straight line travels along the central axis of the transport tube. Since an air flow is formed, a centripetal force due to the high vacuum of the straight air flow at the center acts on the spiral air flow.
Therefore, in the case of a fine powder having a large specific surface area and a small bulk density, the powder can be transported in a non-contact state as much as possible with respect to the inner wall of the transport pipe. This is particularly advantageous when the powder to be transported is easily electrostatically charged.
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.

Embodiments of the method and apparatus of the present invention will be described with reference to the accompanying drawings, which illustrate non-limiting embodiments.
FIG. 1 is an overall schematic view of an apparatus of the present invention for carrying out the method of the present invention.
Referring to FIG. 1, the pneumatic transport device 10 can be used, for example, to pneumatically transport powder contained in a hopper 12 as a powder source to another hopper (transport destination container) 14. Powder can be charged into the powder hopper 12 from a flexible container bag 16 suspended from a hoist.

Schematically, the pneumatic transport apparatus 10 includes a powder supply pipe 18 extending from the powder feeding hopper 12, a spiral airflow generation device 20 connected to the powder supply pipe 18, and the spiral airflow generation apparatus. 20, a solid-gas separation device 24 such as a cyclone connected to the transport tube 22, a bag filter or any other type of filter 26 connected to the cyclone 24, a roots blower, a turbo blower And a negative pressure source 28 including a multistage ring blower, a vacuum pump and the like.
One or more boosters 30 are preferably provided in the middle of the transport tube 22 to sustain or enhance the spiral airflow.

More specifically, a powder cutting device such as a rotary feeder 32 is provided at the lower outlet of the hopper 12, and the powder in the hopper 12 is quantitatively supplied to a T-shaped tube 34 connected to the powder supply pipe 18. It is like that.
Negative pressure from the blower 28 is applied to the T-shaped tube 34 via the transport tube 22 and the powder supply tube 18, and the T-shaped tube 34 is controlled via a filter 36 and a secondary air control valve 38. The specified amount of secondary air is introduced. Another T-tube 40 with a secondary air control valve may be connected downstream of the T-tube 34. Of course, it is also possible to introduce an inert gas or other gas instead of the secondary air.

Details of the spiral airflow generation device 20 will be described with reference to FIG. Since the booster 30 can also be comprised similarly to the spiral airflow generator 20, the description is abbreviate | omitted.
Referring to FIG. 2, the spiral airflow generation device 20 includes a housing 48 having a large diameter inlet 42, a small diameter outlet 44, and a conical portion 46 that connects both.
The rear end of the powder supply pipe 18 is concentrically positioned at the large diameter inlet 42 of the housing 48.
The powder supply pipe 18 and the housing 48 are appropriately fixed to the floor by fixing means (not shown).

An impeller 50 is rotatably disposed between the large-diameter inlet 42 of the housing 48 and the powder supply pipe 18.
As can be seen from FIG. 3, in the illustrated embodiment, the impeller 50 includes a hollow rotating shaft 52 and a plurality of blades 54 extending radially outward, and the blades 54 are fixed to the rotating shaft 52 by welding, joining, or the like. Has been.
The rotating shaft 52 of the impeller 50 is rotatably supported by the powder supply pipe 18 by a pair of bearings 56, for example. As an alternative structure, the rotating shaft 52 of the impeller 50 is expanded and supported by a suitable bearing so as to be rotatable inside the large-diameter inlet 42 of the housing 48, and the blade 54 is radially directed toward the powder supply pipe 18. It may be extended inward.

  The impeller 50 can be rotationally driven by a motor 62 via transmission means such as a pulley 58 and a belt 60 fixed to the rotary shaft 52.

The annular gap between the large-diameter inlet 42 of the housing 48 and the powder supply pipe 18 is divided into a plurality of passages extending in the longitudinal direction by the blades 54 of the impeller 50. These longitudinal passages act as secondary air intake passages.
The amount of secondary air flowing into these secondary air passages can be adjusted, for example, by moving the housing 48 forward and backward with respect to the pulley 58 and increasing or decreasing the gap between the housing 48 and the pulley 58.
Although not shown in the drawings, a honeycomb structure impeller having an axial passage may be used instead of the impeller 50 having the blades 54 extending in the longitudinal direction.

  Preferably, a ferrule 64 is provided at the end of the small-diameter outlet 44 of the housing 48 so that the end of the transport pipe 22 can be connected with one touch by a ferrule clamp device (not shown).

Referring again to FIG. 1, the end of the transport pipe 22 is connected to the inlet 66 of the cyclone 24 as the solid-gas separator 24. A cutting device such as a rotary feeder 68 is provided at the lower outlet of the cyclone 24 so that the solid-gas separated powder can be continuously discharged to the destination hopper 14 while continuously pneumatically transporting. ing.
Continuous pneumatic transportation by using the double damper structure vacuum conveyor described in Japanese Patent Application 2003-3788, Japanese Patent Application 2003-19985, and Japanese Patent Application 2003-29060 instead of the combination of the cyclone 24 and the rotary feeder 68 May be possible.

  Next, the embodiment of the transport method of the present invention and the operation mode of the pneumatic transport apparatus 10 will be described. When the blower 28 is operated, the powder and secondary air cut out from the hopper 12 by the rotary feeder 32 are used. A mixture with the secondary air introduced from the control valve 38 is sucked into the powder supply pipe 18 and an annular gap between the large-diameter inlet 42 of the housing 48 of the spiral airflow generator 20 and the powder supply pipe 18. Secondary air is sucked into the spiral airflow generator 20 through the impeller 50 and the secondary air that has entered the spiral airflow generator 20 and the powder and air sent from the powder supply pipe 18. The mixture is sucked into the cyclone 24 through the transport pipe 22, and the solid-gas separated powder in the cyclone 24 is continuously discharged to the transport destination hopper 14 by the rotary feeder 68.

When the impeller 50 is rotationally driven by operating the motor 62, the secondary air flowing in the longitudinal direction from the longitudinal passage between the blades 54 of the impeller 50 is given a circumferential linear velocity by the impeller 50, As shown in FIG. 2, a spiral air flow 70 swirling along the inner periphery is generated inside the housing 48.
On the other hand, as indicated by an arrow 72 in FIG. 2, the mixture of the powder and air from the powder supply pipe 18 is sucked into the housing 48 in the form of a straight air flow.

As a result, as schematically shown in FIG. 4, a relatively high vacuum straight air flow 74 is maintained along the central axis of the transport pipe 22 over a predetermined section of the transport pipe 22, and A relatively low vacuum spiral air flow 70 is maintained along the inner peripheral wall. For this reason, since the centripetal force due to the high vacuum of the straight airflow 74 at the center acts on the spiral airflow 70, the spiral airflow 70 is sucked to the center and forward like a tornado.
Therefore, the powder can be conveyed while avoiding the powder from contacting the inner wall of the transport pipe 22, and in the case of a fine powder having a small bulk density, the powder can be conveyed in a non-contact state.
Under the condition that the spiral airflow 70 does not continue over the entire length of the transport pipe 22, the spiral airflow is maintained or enhanced by inserting one or more boosters 30 in the middle of the powder transport pipe 22.

  Although specific embodiments of the present invention have been described above, the present invention is not limited to them, and various modifications and changes can be made. For example, a gas other than air can be used as the powder transport fluid.

It is the whole transport apparatus of the present invention for carrying out the method of the present invention. It is a fragmentary sectional view of the spiral airflow generation device 20 shown in FIG. FIG. 3 is an end view of the impeller shown in FIG. 2. It is typical sectional drawing of the transport pipe shown in FIG.

Explanation of symbols

10: Transport device 12: Powder input hopper (powder source)
14: Destination hopper 18: Powder supply pipe 20: Spiral air flow generator 22: Transport pipe 28: Suction means 30: Booster 42: Large diameter inlet 44 of housing 44: Small diameter outlet 46 of housing 46: Conical section 48 of helix Airflow generator housing 50: impeller 50/60/62: rotational drive means

Patent Applicant YMS Co., Ltd. Attorney Hiroshi Ito

Claims (4)

A transport tube from the powder source to the powder delivery destination container through (22) Upon the powder is transported by suction, radial center portion of the transport tube at the upstream end of the transport tube (22) (22) (72) supplies powder, radially outer and transport tube (22) secondary gas (70) to the inner peripheral wall side of the supply to the powder transport continuously the central portion (72), the transport tube (22 ) In the transport pipe (22) along the inner peripheral wall thereof by swirling the secondary gas flow (70) flowing into the upstream end in the circumferential direction along the inner circumference of the transport pipe (22) . A suction-type powder transportation method, wherein a spiral air flow (70) is continuously generated during transportation. In order to transport the powder from the powder source to the powder destination container via the transport pipe (22) disposed between the powder source and the powder destination container, and the transport pipe (22). A suction means (28) for sucking the downstream end of the transport pipe, and a powder supply pipe (18 ) having an outer diameter smaller than the inner diameter of the transport pipe (22) and opening in the center of the upstream end of the transport pipe (22). ) and the transport pipe (the powder supply tube at the upstream end of the 22) (18) and the transport pipe (the transport pipe from the secondary gas inlet which annular gap is formed between the inner peripheral wall 22) (22) the secondary gas flow into the in powder delivery continuously (70) in the circumferential transport pipe by providing direction velocity (22) transport pipe (22) in the powder transport continuously along the inner peripheral wall of the inside spiral airflow generating device for generating a spiral air flow (70) to (20) and characterized in that it comprises a suction type powder delivery device A spiral airflow generating device to be used for suction type powder delivery method or device according to a spiral air flow based on claim 1 or 2 (20), in order to connect the large-diameter opening (42) powder delivery tube (22) A housing (48) comprising a small diameter outlet pipe (44 ) having the same diameter as the powder transport pipe (22), and a conical portion (46) connecting the large diameter inlet (42) and the small diameter outlet pipe (44 ) ; , rotatable annular gap between said concentrically arranged powder supply pipe to the inside of the large-diameter opening (42) (18), the large-diameter opening (42) a powder supply pipe (18) A spiral airflow generation device comprising: an impeller (50) disposed on the inner side of the motor and driving means for rotationally driving the impeller. A spiral airflow booster device (30) inserted in the middle of a powder transport tube (22) in order to sustain or enhance the spiral airflow in a suction type powder transportation method or device according to claim 1 or 2 , A large-diameter inlet (42) adapted to receive an upstream powder transport pipe, a small-diameter outlet pipe (44) for connecting the downstream powder transport pipe, and the large-diameter inlet and small-diameter outlet pipe are connected. A housing (48) having a conical portion (46) for rotating, an impeller (50) rotatably disposed in an annular gap between the large-diameter inlet and the upstream powder transport pipe, and the impeller And a drive means for rotationally driving the booster device.

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