JPS6332685B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a hopper powder bridging prevention device.

Generally, granules such as grains or powders such as sand, cement, and mirabilite are stored in a hopper, and the hopper is continuously or intermittently discharged from a discharge port provided at the end of an inverted conical or inverted pyramid shape whose cross-sectional area gradually decreases. It is being discharged. However, when granules are being continuously discharged, there are relatively few problems; however, due to the adhesive force and frictional force of the granules, pressure is applied to a certain layer of the granules from the granules above. Even if the supporting force below that layer becomes zero, a statically balanced bridge may be created. This phenomenon is severe when the adhesion force and frictional force are large, and even more so when the powder or granules are discharged intermittently. For that reason, the special public service was issued in 1977-9504.
As in Japanese Patent Publication No. 48-7973, a technique has been proposed in which multiple compressed air supply pipes extending horizontally within the hopper are provided and compressed air is jetted downward or upward to prevent the occurrence of bridging. ing. However, with large adhesion and frictional forces, it has been impossible to completely eliminate the bridging that occurs on the wall. In addition, because a large amount of compressed air is ejected without sufficiently checking the occurrence of bridging in the hopper, the pressure inside the hopper becomes high partially or throughout the hopper, resulting in uneven discharge of powder and granules and a large amount of compressed air. It had the disadvantage of requiring air.

The present invention was obtained as a result of studies aimed at solving the drawbacks of the powder bridging prevention device as described above.

That is, the present invention installs powder and granule detectors at the horizontal center and near the walls of the hopper, as well as at multiple locations in the vertical direction. The hopper is installed in correspondence with the powder and granule detectors installed at each position in the vertical direction, and the pressure fluid is ejected into the hopper from the pressure fluid supply pipe located at the corresponding position based on the signal from the powder and granule detector. The object of the present invention is to provide a device for preventing bridging of powder or granular materials in a hopper, which is characterized in that it is configured to

Fig. 1 is a schematic sectional view of one embodiment of a hopper equipped with the powder bridging prevention device of the present invention, Fig. 2 is a Z-Z arrow view, and Fig. 3 is a schematic enlarged view of a pressure fluid supply pipe. FIG. 4 shows a YY arrow view, and the configuration will be explained based on the drawing.

Reference numeral 1 designates a hopper for powder and granular material, which is formed from a vertical wall 2, a lid portion 3 having a supply port 4, and an inclined bottom portion 5 having a discharge port 6. 7 is a main supply pipe of compressed air. 8a to 8f are compressed air supply pipes installed adjacent to the vertical wall of the hopper 1, with a nozzle 9 having an ejection port facing the center of the hopper and diagonally downward, and a nozzle 9 having a jet port facing the wall and diagonally downward. A nozzle 10 with a spout is provided. 11a-1
1f is a compressed air supply pipe installed along the inclined bottom 5 of the hopper 1, with a nozzle 12 having an ejection port facing the center of the hopper and diagonally downward; A certain nozzle 13 is provided. Reference numeral 14 designates a powder/granular material detector provided adjacent to the vertical wall portion 2 of the hopper 1, and 15 designates a powder/granular material detector provided at approximately the same horizontal position as the detector 14 and approximately at the center of the hopper. .
Reference numeral 16 denotes a powder/grain material detector provided at a position adjacent to the inclined bottom portion 5 of the hopper 1, and reference numeral 17 designates a powder/grain material detector provided at substantially the same horizontal position as the detector 16 and substantially at the center of the hopper. The above powder detector 14,1
Preferably, the components 5, 16, and 17 are commercially available products and can be easily attached to the hopper 1, such as a tuning fork type level controller, a capacitance type level meter, or a rotary type level meter. A controller 18 determines the presence or absence of powder and the occurrence of bridging based on the operation signals of the powder detectors 14 to 17, and instructs the compressed air supply operation. 19a to 19f are electromagnetic valves disposed between the main compressed air supply pipe 7 and the supply pipes 8a to 8f, respectively, and 20a to 20f are electromagnetic valves disposed between the main compressed air supply pipe 7 and the supply pipes 11a to 11f, respectively. This is a solenoid valve installed.

The powder discharge operation in the powder bridging prevention device of the hopper having the above structure will be explained.

First, powder and granules are supplied from the supply port 4 of the hopper 1, and when a predetermined amount of powder and granules are supplied into the hopper 1, a rotary valve (not shown) attached to the discharge port 6 is operated to sequentially supply a predetermined amount of powder and granules. discharge. At this time, the powder detectors 14, 16 and 15, 17 operate at predetermined intervals, and the ON and ON signals from the detectors 14 and 15 are also ON and ON from the detectors 16 and 17, respectively. If the signal is sent to the controller 18, it indicates that the powder is above the detectors 14 and 15, and the particles are sent from the detectors 14 and 15, respectively.
OFF and OFF signals are sent from detectors 16 and 17, respectively.
When ON and ON signals are sent to the controller 18, it indicates that the powder is below the detectors 14 and 15 and above the detectors 16 and 17; , respectively OFF from 17,
When an OFF signal is sent, the powder or granules are below the detectors 16, 17, indicating that it is necessary to newly supply powder or granules to the hopper.
If the detectors 14 and 15 send OFF and ON signals, and the detectors 16 and 17 send ON and ON signals, respectively, this indicates that the powder is near the detectors 14 and 15. This indicates that the powder and granular material in the hopper 1 is in a normal state.

If the ON and OFF signals from the detectors 14 and 15 are sent to the controller 18, and the ON and ON signals from the detectors 16 and 17 are sent to the controller 18, as shown in FIG. Detectors 14 and 15 turn on and off, respectively, indicating that a bridge has occurred in the section.
The OFF signal turns ON from detectors 16 and 17, respectively.
If an OFF signal is sent, it indicates that a bridge has occurred in the entire hopper 1 as shown in FIG.
The ON signal is turned OFF from detectors 16 and 17, respectively.
If an OFF, or ON, OFF signal is sent, this indicates that a bridge has occurred in the inclined bottom portion 5 of the hopper 1, as shown in FIG. In such a case, the controller 18 controls the solenoid valves 19a to 19.
f or the solenoid valves 20a to 20f, each solenoid valve is sequentially opened and closed at predetermined intervals (1 to 30 seconds), and compressed air is supplied to the nozzles 9, 10 of the supply pipes 8a to 8f and the supply pipes 11a to 11a. 11f nozzle 1
2 and 13, each ejects for several seconds (1 to 5 seconds). The compressed air ejected from the nozzles 9 and 12 toward the center of the hopper blows away the bridge of the powder and granules located on the center side of the hopper, breaking the bridge, and the air is ejected from the nozzles 10 and 13 toward the wall. The compressed air lifts the bridging of the powder and granular material located on the wall from the wall surface and pushes it downward to blow it away, making it possible to completely eliminate the bridging in a short time.

Although the present invention can be practiced as described above, it is not limited to the examples.

The shape of the hopper may be a cylinder with a conical lid and an inverted conical bottom connected to each other as in this embodiment, a square cylinder with a pyramidal lid and an inverted pyramidal bottom connected, or The lid may be configured as a flat lid.

The pressure fluid may be compressed air or an inert gas.

The inside of the hopper may have an air atmosphere, or may be replaced with an inert gas such as N ₂ gas.

The number of pressure fluid supplies is set according to the size of the hopper, and they may be provided on the same line on the vertical wall and the inclined bottom, or in a staggered manner (Fig. 5).
It may be placed in

Particle detectors were installed in two vertical locations, one on the wall and one in the center, but in order to more precisely detect the occurrence of bridging and eliminate bridging, more locations should be installed in the vertical direction. In addition, a plurality of pressure fluid supply pipes may be provided around the wall, and pressure fluid may be supplied only to pressure fluid supply pipes corresponding to partially generated bridging.

The shape of the nozzle provided in the pressure fluid supply pipe, the direction of the spout, and the installation position are determined depending on the adhesion force, frictional force, etc. of the powder and granular material.

It is advisable to make a small hole at the lower end of the pressure fluid supply pipe to prevent water from remaining during cleaning.

Setting the opening/closing order and opening/closing time of the solenoid valves of the pressure fluid supply circuit based on the signal from the powder/granular object detector may be performed by a control device having an operation setting circuit, a comparison calculation circuit, an operation command circuit, etc. , a timer, etc. may be used in combination.

The ejection time of the pressure fluid is short, 1 to 5 seconds.
The pressure fluid may not be ejected from all the pressure fluid supply pipes at the same time, but may be ejected sequentially at predetermined intervals (1 to 30 seconds), and the ejection order may be sequential or random from adjacent supply pipes.

As described above, the present invention installs powder and granule detectors at the horizontal center and near the walls in the hopper, as well as at multiple locations in the vertical direction. Supply pipes are installed in correspondence with the powder and granule detectors installed at each position in the vertical direction, and pressure fluid is supplied from the pressure fluid supply pipes at the corresponding positions based on signals from the powder and granule detectors. Since the jet is made to eject into the hopper, it is possible to accurately detect the location and situation of bridging, that is, all bridging patterns, and to ensure that all types of bridging that occur in the hopper are destroyed with the minimum amount of fluid necessary. It can be done.

In addition, as mentioned above, since the bridge can be destroyed with the minimum amount of fluid required, the pressure inside the hopper will not increase or the pressure balance will collapse, resulting in variations in the amount of powder and granular material being supplied and discharged. There is no.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view showing one embodiment of a hopper equipped with a powder bridging prevention device of the present invention, and FIG. 2 is a view taken along the Z--Z arrow in FIG. 1. FIG. 3 is a schematic enlarged view of the pressure fluid supply pipe, and FIG. 4 is a view along the YY arrow in FIG. 3. FIG. 5 is a schematic diagram showing another arrangement of the pressure fluid supply pipe. FIGS. 6 to 8 are schematic diagrams showing the occurrence of bridging in powder and granular materials. 1...Hopper, 2...Vertical wall, 5...Slanted bottom, 7
...Compressed air supply main pipes, 8a to 8f, 11a to 1
1f...Compressed air supply pipe, 9, 10, 12, 13
... Nozzle, 14, 15, 16, 17... Powder detector.

Claims (1)

[Claims] 1 Particle detectors are installed in the horizontal center of the hopper, near the walls, and at multiple locations in the vertical direction, and pressure fluid supply pipes with multiple spouts are installed in each of the vertical directions. The hopper is installed in correspondence with a powder/granular material detector installed at a position, and pressure fluid is jetted into the hopper from a pressure fluid supply pipe located at a corresponding position based on a signal from the powder/granular material detector. A hopper powder bridging prevention device characterized by the following.