Patent Application
20130277477
The invention relates to a roller crusher of the type which comprises a pair of crushing rollers, generally parallel to one another and rotating in opposite directions, towards each other, each roller including a shaft which has end portions, mounted in respective roller bearings, and a feeding arrangement for feeding material to be crushed to a crushing zone of said roller crusher.
When materials are crushed or pulverised in a roller crusher, two rotatably mounted crushing rollers, separated from each other by a gap, form a draw-in nip where the materials are drawn in, force fed or fed by gravity and crushed or ground between the rolls and against each other in a process which may be called interparticle crushing. Each of the crushing rollers is mounted on a shaft in the roller crusher, which shaft has end portions mounted in respective roller bearings. An advantage of this type of crushing is that an effective crushing may be achieved, even to very small grain sizes, with reduced energy consumption as compared to many other crushing techniques. Further, the level of noise during the process is essentially reduced as compared to other crushing techniques.
During the crushing operation, a large amount of dust is created and naturally spread to the surroundings of the crushing roller. The dust creates a serious problem when it reaches the bearings of the roller crusher, since the operation of the bearings is easily degraded by the dust. In addition, other vital parts of the roller crusher may also be affected by the dust.
Conventional roller crushers solve this problem by adding local protective equipment on the parts that risk being affected by the dust (see, e.g., U.S. Pat. No. 3,833,273). This is a both expensive and time consuming procedure. In addition, the risk of the dust spreading to other adjacent machines and personnel as well as to parts that have not received any protective equipment remains.
It is an object of the present invention to provide an improvement of the above technique and prior art. More particularly, it is an object of the present invention to provide an improved roller crusher preventing the spreading of dust.
These and other objects as well as advantages that will be apparent from the following description of the present invention are achieved by a roller crusher according to the following features.
A roller crusher of the type which comprises a pair of crushing rollers is provided. The crushing rollers are generally parallel to one another and rotate in opposite directions, towards each other, each roller including a shaft which has end portions, mounted in respective roller bearings. The roller crusher comprises a feeding arrangement for feeding material to be crushed to a crushing zone of the roller crusher. The roller crusher is characterized in that it further comprises a dust protecting enclosure enclosing the crushing zone, the dust protecting enclosure having an inlet opening upstream of the crushing zone and in communication with said feeding arrangement, and an outlet opening downstream of the crushing zone, and in that the roller bearings are arranged outside of the dust protecting enclosure. This is advantageous in that, since the entire crushing zone is enclosed by the dust protecting enclosure, the dust is completely prevented from spreading to the roller bearings and to other places where it might cause problems. The only way for the dust to move is downwards and out through the outlet opening where no sensitive parts are affected by the dust. Accordingly, no local protective equipment is needed on the roller crusher and the risk of the dust spreading to other adjacent machines and personnel as well as to parts that have not received any protective equipment is eliminated. Another advantage is that the procedure of equipping the crushing zone with such a dust protection enclosure is inexpensive and easily performed in relation to the conventional dust protection procedures.
The crushing rollers may be at least partly enclosed in the dust protecting enclosure or completely enclosed in the dust protecting enclosure depending on which embodiment of the invention is preferred.
The dust protecting enclosure may comprise side walls which are easy and cheap to manufacture and to mount in the roller crusher.
At least one side wall may comprise an inspection window, which is advantageous in that the crushing operation as well as the parts involved can be monitored from the outside at any time. Naturally, the dust protection enclosure may comprise additional inspection windows and inspection doors for monitoring. Also, maintenance doors may be provided in order to facilitate maintenance of the roller crusher.
The side walls may be releasably mounted to the roller crusher or to a foundation on which the roller crusher is arranged. When the crushing rollers or any other parts located within the crushing zone needs maintenance or replacement, easy access will be provided by means of the releasably mounted side walls.
The feeding arrangement may comprise a funnel and may be sealingly connected to the inlet opening, which results in an even more secure area without any leakage of dust.
Generally, all terms used below are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to “a/an/the [element, device, component, means, etc]” are to be interpreted openly as referring to at least one instance of said element, device, component, means, etc., unless explicitly stated otherwise.
The above, as well as additional objects, features and advantages of the present invention, will be better understood through the following illustrative and non-limiting detailed description of preferred embodiments of the present invention, with reference to the appended drawings, where the same reference numerals will be used for similar elements, wherein:
In
The dust protecting enclosure 7 can both be placed in the roller crusher 1 during the manufacture of the roller crusher 1 as well as later on in an already existing roller crusher 1 of the type illustrated in
During the crushing operation of the roller crusher 1, the material to be crushed is transported to the feeding arrangement 6 of the roller crusher 1 and introduced in the funnel of the feeding arrangement 6. The material to be crushed then travels by gravity from the feeding arrangement 6 to the crushing zone Z via the inlet opening 10 of the dust protecting enclosure 7, which is completely enclosing the crushing zone Z. When the material has been crushed by means of the two parallel and rotating crushing rollers 2, it travels by gravity out of the crushing zone Z via the outlet opening 11 in order to be transported from the plant.
In the embodiment shown in
The invention has mainly been described above with reference to a few embodiments. However, as is readily appreciated by a person skilled in the art, other embodiments than the ones disclosed above are equally possible within the scope of the invention, as defined below.
For instance, the dust protecting enclosure need not necessarily enclose the rolls entirely. Instead, the shorter side walls could be arranged approximately at a central axis of the rollers and extend down from the top of the dust protecting enclosure to a level slightly above the crushing surface of the rollers. This would lessen the dust protecting efficiency, since dust could leak out under the shorter side walls. However, this could be compensated for by adding evacuation equipment adjacent the lower edge of the shorter side walls for evacuating dust. Alternatively, the dust protecting efficiency could be improved by adding a flexible skirt made of, e.g. elastomeric material, at the lower edge of the shorter side walls.
The dust protecting enclosure may be equipped with hatches or doors for inspection and/or maintenance of the rollers. These may be arranged in one or more of the side walls and/or in the top wall of the enclosure.
It should be noted that, although the enclosure has been referred to as a dust protecting enclosure, it may also act as a noise reducer, especially if sound insulating material is arranged on the side walls.
