JPS6331318B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of the Invention] The present invention relates to a method for controlling a solid waste volume reduction device, and more specifically, to a method for significantly reducing the volume of municipal waste including plastics or solid waste from a nuclear power plant. The present invention relates to a control method for a solid waste volume reduction device that enables stable continuous operation.

[Background of the invention] So-called uncombustible garbage, which includes various types of plastics, metals, glass, rubber, etc., discharged from households and factories is disposed of by methods such as incineration, landfill, and resource recovery. However, each of these processes has its own problems. The main causes are often various plastics in the garbage, such as melting during incineration, clogging of the furnace due to adhesion, damage to the furnace due to local heating, and generation of harmful gases such as chlorine and dioxins. In addition, many bulky items, such as styrofoam, polyethylene sheets, and bags, are often disposed of in landfills, which incurs transportation costs, and even after landfilling, they can be exposed from the surface and blown away by the wind, polluting the environment. Recently, various methods of collecting and reusing various plastics have been proposed from the perspective of effective resource utilization.
Municipal waste contains a variety of miscellaneous items, and has the disadvantage that sorting it is rather expensive.

Therefore, we focused on the characteristics of the thermoplastic plastics contained in these municipal garbage.
A method has been proposed in which a coarse granular mixed solidified material is obtained by adding granular inorganic substances (sand, crushed stone, incinerated ash, etc.) (Japanese Patent Publication No. 11273/1983).
In this method, metal pieces, cloth, etc. are not subject to granulation, and treatment after separation is required.

On the other hand, polysheet, paper waste, and cloth waste contaminated with radioactive materials during work at nuclear power plants, etc.
Concrete pieces, steel materials, high-performance filters, insulation materials, etc. are generated, and these are packaged in plastic bags as miscellaneous solids, and depending on the case, are classified into flammable, non-flammable, or non-combustible, and stored in drums. , has been stored.

For example, waste products such as high-performance filters that are made up of wood, filter media (inorganic materials), metal plates, etc. must be dismantled and sorted, which complicates the process.
A problem arises in that the possibility of worker exposure to radiation increases.

These drums have been stored in storage, but the storage space has become smaller than expected, so we decided to incinerate what can be incinerated among these miscellaneous solid wastes, and store the incinerated ash directly in drums or solidify it with cement. etc. It is a more stable solid substance. Since this incineration process targets bulky items such as polysheets, plastic bags, paper waste, cloth waste, etc., its volume reduction effect is extremely large, and it is widely used in waste treatment at nuclear power plants, RI facilities, etc. It's coming.

However, if a large amount of plastic is incinerated, the furnace may be damaged, and it is necessary to attach a waste gas treatment device to the incineration treatment device, which also generates secondary waste, which also has the disadvantage of increasing equipment costs.

Another method for treating miscellaneous solid waste is compression and volume reduction using a press.
A high pressure compression volume reduction device of about 3000Kg/cm ² is being developed. According to this method, polysheets, plastic bags, paper waste, cloth waste, etc. can be compressed with almost no gaps, and it is an effective method for volume reduction. However, in this method, the obtained compressed body itself is a collection of heterogeneous objects, which is not preferable for long-term storage.

In order to solve the above-mentioned problems, the present inventors filed a patent application for a solid waste volume reduction device as shown below.

This solid waste volume reduction device houses a rotary shaft equipped with continuous helical blades inside a hollow cylindrical body having a waste input section, an external heating section, and a waste exit section. The upper end side of the rotating shaft is connected to the power part through a supporting means that allows the shaft to swing, and a clearance is provided between the blade and the wall surface of the hollow cylindrical body to prevent the solid waste from bridging, and The present invention is characterized in that the waste outlet section is provided with a waste outlet nozzle section that enables compression of the waste. Here, FIG. 1 shows a schematic diagram of this solid waste volume reduction apparatus. In the figure, 1 is a hollow cylindrical body, 1a is a waste input part, 1b is an external heating part, 1c is a waste outlet part, 2 is solid waste, 3 is a blade, 4 is a rotating shaft, and 5 is a connector. (Support means), 6
is a power part, 7 is a free bearing, 8 is a heating means, and 9 is a waste outlet nozzle.

To briefly explain this solid waste volume reduction device, first, the input solid waste 2 is transferred to the rotating shaft 4.
It is gradually transferred in the direction of the external heating 1b by the rotation of the spiral-shaped continuous blades 3 supported by. The clearance between the blades 3 and the inner wall of the hollow cylindrical body 1 is set so that the solid waste 2 is bridged, and the solid waste 2 is crushed and pulverized in this gap.

This solid waste volume reduction device can significantly reduce the volume of miscellaneous solid waste through integrated processing, and has various advantages such as being able to contain radioactive substances, heavy metals, and other harmful substances in plastic. have.

However, some problems still remain when reducing the volume of solid waste using this volume reduction device.

For example, in conventional screw feeders or screw conveyors, the clearance between the screw and the inner wall of the conveyor or feeder is less than 2 mm, so solid waste can get caught between the outer pipe and the screw, causing trouble. However, the solid waste volume reduction device described above is characterized by crushing, pulverizing, and mixing the solid waste by biting the solid waste in the gap between the blade and the inner wall of the cylindrical body. This may cause the blades to be twisted or damaged, and furthermore, the operation of the device may have to be stopped.

[Object of the Invention] The present invention has been made in order to solve the above-mentioned drawbacks in volume reduction of solid waste volume reduction equipment.
It is an object of the present invention to provide a control method for a solid waste volume reduction apparatus that stabilizes the operation of the solid waste volume reduction apparatus described above.

[Structure of the Invention] The method for controlling a solid waste volume reduction device of the present invention is a method for controlling the solid waste volume reduction device, and comprises controlling a current flowing through a power unit such as a motor or the like. The present invention is characterized in that when the torque applied to the power unit exceeds a preset value and this value is maintained for a predetermined period of time or more, the rotation of the rotating shaft is reversed for a certain period of time. When a volume reduction device is in operation, a certain amount of torque is applied to the motor, etc., and when that value is maintained, solid waste is often trapped between the blades and the inner wall of the cylindrical body, and the torque remains as it is. If left in this condition, the motor etc. may seize or the blades may be damaged or broken. Therefore, if the current flowing through the motor, etc. or the torque borne by the motor, etc. reaches a certain set value or more, and the value is held for more than a predetermined time, the motor, etc. is rotated in the reverse direction, and the solid waste that was being held can be disposed of. An object can be released from the gap between the blade and the inner wall of the cylindrical body, and when the rotation is returned to normal after a certain period of time, the current value or torque can be returned to the normal operating current value or torque. Here, as shown in Figure 2, after the current value or torque reaches a certain set value, the value above the set value is held for a predetermined time (A sec), that is, for a period of time that does not damage the motor or blades. The motor may be reversely rotated at points a and b after detecting this. In this way, it is possible to prevent damage or breakage of the blades without placing an excessive burden on the motor or the like or the blades.

In the present invention, as a method of controlling the rotation of the rotary shaft, the number of times the rotary shaft is reversed is counted, and when the number of reverses reaches a certain count within a certain period of time, the rotation of the rotary shaft is stopped. You may use this method. In other words, if the rotating shaft is reversed frequently, it is necessary to inspect the apparatus because it is an abnormal situation where solid waste is trapped.

In the present invention, when a shredding machine is installed or included, it is necessary to stop the shredding machine at the same time when the rotation of the rotating shaft is stopped as described above.

The method for controlling the solid waste volume reduction apparatus of the present invention will be explained below based on Examples and Comparative Examples.

Comparative Example 1 When using the solid waste volume reduction device shown in Figure 1, a piece of wood measuring 50 x 100 x 20 mm was introduced at a rotation speed of 16.6 rpm. As a result, the rotating shaft at section B in the figure became twisted.

Example 1 In the same device as in Comparative Example 1, when the rotating shaft was replaced and the device was operated again under the same conditions, a piece of wood got caught in the blade and a heavy load was applied to the motor. This situation was confirmed by the change in current value over time, as shown in Figure 3. 2 seconds after the motor current reached 15A or higher, the rotation direction was reversed for 10 seconds and the current returned to normal.

After several hours of continuous operation using this control method, no twisting of the rotating shaft or damage to the blades occurred.

[Effects of the Invention] As explained above, according to the control method of the solid waste volume reduction device of the present invention, it is possible to significantly reduce the volume of municipal waste including plastics or solid waste from nuclear power plants. Furthermore, it is possible to provide a method for controlling a solid waste volume reduction device that prevents damage or breakage of a power unit such as a motor or a blade, and enables stable continuous operation.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of the solid waste volume reduction device used in the present invention, and Fig. 2 shows the relationship between the forward rotation or reverse rotation time of the motor and the current value flowing through the motor or the torque applied to the motor. FIG. 3 is a diagram showing the time of forward rotation or reverse rotation of the motor and the current value flowing through the motor in Example 1. 1...Hollow cylindrical body, 1a...Waste input part, 1b
...External heating section, 1c...Waste outlet section, 2...Solid waste, 3...Blade, 4...Rotating shaft, 5...Connector, 6...
Power unit, 7... Free type bearing, 8... Heating means, 9...
Waste outlet nozzle, A... Part where a piece of wood got stuck, B... Part where the shaft was twisted.

Claims (1)

[Scope of Claims] 1. A rotating shaft equipped with continuous spiral blades is housed inside a hollow cylindrical body having a waste input section, an external heating section, and a waste exit section, and the upper end side of the rotating shaft is is connected to the power unit via a supporting means that can oscillate, and a clearance is provided between the blade and the wall surface of the hollow cylindrical body to cause bridging of solid waste. A method for controlling a solid waste volume reduction device equipped with a waste outlet nozzle section that enables compression of the solid waste, wherein the current flowing through the power section or the torque borne by the power section is determined in advance. A method for controlling the solid waste volume reduction apparatus, characterized in that when the temperature exceeds a set value, the rotation of the rotating shaft is reversed for a certain period of time. 2 The number of times the rotation of the rotating shaft is reversed is counted, and the rotation of the rotating shaft is stopped when the number of times the rotation of the rotating shaft is reversed reaches a certain count within a certain time. A method for controlling a solid waste volume reduction device according to scope 1. 3. The method of controlling a solid waste volume reduction apparatus according to claim 2, wherein a shredder attached to or attached to the volume reduction apparatus is stopped when the rotation of the rotating shaft is stopped.