1. Technical Field
The present invention relates to a crushing method for waste containing materials that are unfit for crushing, and an apparatus for its practice. The method is capable of crushing waste such as home electric appliances, etc. discharged as non-inflammable bulky refuse from households, etc., for example, without deforming massive materials that are difficult to crush such as a motor, compressor, etc. contained in the waste, while separating the crushed material from those materials that are unfit for crushing.
2. Background Art
Conventionally, hammer crushers, biaxial crushers, triaxial crushers, etc. are used for the crushing of waste such as home electric appliances, etc.
In the crushing of waste such as home electric appliances, etc. or refrigerators, for example, the frame material, etc. of the refrigerator can be crushed directly, but massive materials such as the motor and compressor, etc. are difficult to crush.
A manner has therefore been adopted for manually removing such massive materials in advance of crushing, and then crushing of the frame material, etc. by using crushers is performed.
However, a problem with this method is that it requires much manual labor for the removal of the massive materials such as the motors and compressors, etc.
On the other hand, treating a refrigerator with a crusher without removing the motor and compressor presented a problem of extremely low recovery ratio of valuables, because the motor and compressor are deformed as a result of the crushing and become difficult to disassemble after the crushing.
Moreover, a problem with a hammer crusher is that it is dangerous because of the possibility of an explosion, which is liable to result depending on the type of materials mixed in the waste.
In view of these problems inherent in the crushing of waste containing materials that are unfit for crushing, the present inventor et al. proposed a crushing method for waste containing materials that are unfit for crushing and an apparatus for performance of the method. The method and apparatus are capable of separating and discharging materials that are unfit for crushing without deforming them, while crushing object material that is to be crushed, such as a frame member, etc., and thereby improving the recovery ratio of valuables, even in the case where the waste is directly submitted to crushing without removing materials that are unfit for crushing, such as a motor, compressor, etc. in advance of the crushing. (PCT/JP98/04791).
An outline of such a crushing method and apparatus is indicated in FIG. 7 to FIG. 10.
This crusher 50 comprises a first crushing roller 10 on one side under a hopper 2 of a casing 3 that forms the hopper 2 at its top and is open at its bottom. A second crushing roller 11 is positioned at the back of the crushing roller 10, and a third crushing roller 12 faces this second crushing roller 11.
On another side under the hopper 2 is provided a push-in mechanism 13 facing the crushing roller 10, while on a bottom plate 2a of the hopper 2 directly under the first crushing roller 10 is provided a supporting projection 14.
Thus, when the waste W containing materials M that are unfit for crushing, such as a motor, compressor, etc. of home electric appliances, are injected in the hopper 2, these materials are pushed by the push-in mechanism 13, toward the first crushing roller 10. Then, to prevent free move of the waste W, the waste W is supported by the supporting projection 14, and the first crushing roller 10 bites into the waste W, thereby accurately crushing the waste W while conveying it.
The first crushing roller 10 is constructed, as shown in FIG. 8, by attaching a large number of crushing blades 21 at coarse intervals "a" on a rotary shaft 20 such that the crushing blades 21 project from the rotary shaft 20.
These crushing blades 21 are formed with a height "b", which allows them to easily bite into the waste W while the materials M that are unfit for crushing contained in the waste W are received within the gaps between the crushing blades 21, and then pass through these gaps without being crushed by the first crushing roller 10. Preferably, the tips of the crushing blades 21 are oriented at an acute angle so that the tips may easily bite into the waste W.
Furthermore, the casing 3 directly above the first crushing roller 10 is provided with a stationary knife 22 to be inserted in the gaps between the crushing blades 21 of the first crushing roller 10, so as to scrape from the crushing blades 21 the crushed material which sticks to the crushing blades 21.
The second crushing roller 11 is realized by attaching screw blades 25 onto a rotary shaft 24, as shown in FIG. 9, and these screw blades 25 are designed to have a coarse pitch and a height enabling the materials M that are unfit for crushing to be received within the gaps between the screw blades 25 and pass therethrough without being crushed, while crushing object materials that are to be crushed, such as frame member, etc., as the second crushing roller operates in combination with the third crushing roller 12.
A screw blade 25 is constructed from screw blades 25a and 25b, which are twisted in directions opposite to each other and formed by splitting a single screw into two pieces. The screw blades 25a and 25b are to prevent the object material that is to be crushed from moving sideways at the time of crushing.
The third crushing roller 12 is realized by attaching, as shown in FIG. 10, main screw blades 27 and auxiliary screw blades to a rotary shaft 26. The auxiliary screw blades 28 have a coarser pitch as compared with that of the main screw blades 27, and are twisted in the direction opposite to the main screw blades 27, such that grids "g" are formed between the main screw blades 27 and the auxiliary screw blades 28. The main screw blades 27 and auxiliary screw blades 28 have a height that enables the materials M that are unfit for crushing to be received within these gaps or grids "g" and pass therethrough without being crushed.
The main screw blades 27 and the auxiliary screw blades 28 are constructed from screw blades 27a, 27b, 28a, 28b, which are twisted in directions opposite to each other and formed by splitting respective screws into two pieces each. The opposite directions of twist are to prevent the object material that is to be crushed from moving sideways at the time of crushing.
And, on the discharge side of the casing 3 is provided a conveyor 16.
This conveyor 16, installed at a required inclination, is designed to make the materials M that are unfit for crushing, in massive state without being crushed, tumble from the conveyor 16 after being discharged on the conveyor 16. The conveyor 16 is also designed to move the crushed and flattened object material upward when discharged on the conveyor 16, without rolling or sliding of the crushed and flattened object material, so as to discharge the crushed and flattened object material while automatically separating the crushed and flattened material from the materials that are unfit for crushing. This conveyor 16 is constructed in such a way that its inclination may be adjustable as desired.
According to this crusher of waste, although it is possible to achieve a certain objective of separating and discharging materials that are unfit for crushing without deforming them, the waste W supplied by the hopper 2 and pushed by the push-in mechanism 13 to the side of the first crushing roller 10 has its top face part crushed by the first crushing roller 10 while its bottom face part is conveyed toward the second crushing roller 11 and the third crushing roller 12 along a discharge guide chute 17 together with the materials M that are unfit for crushing in an uncrushed state.
For that reason, the crushing of the bottom face part of the waste W and the separation of the materials M that are unfit for crushing must be performed at the same time by the second crushing roller 11 and the third crushing roller 12, which face each other, thereby presenting a problem of difficulty of separation in some cases.