What is the need of Feeders?
The arrival of ore from a mining face is intermittent in nature in the form of skips, lorries, trucks, and other handling vehicles. Once the ore arrives to primary crushing stage they are crushed as soon as possible. Once crushing operation starts the subsequent operations require steady feed. Surge bins are provided at different points in the process chain for convenient holding arrangement to receive all the intermittent feed and also to act as a temporary storage. Retrieving ore from these surge bins required feeders otherwise ore will not flow evenly through any kind of gate mechanism.
How a feeder works?
Feeding is essentially a conveying operation in which the distance travelled is short and in which close regulation of the rate of passage is required. A typical feeder consists of a small bin, which may be an integral part of a large bin, with a gate and a suitable conveyor. The passage of ore through the bin is regulated by the feeding mechanism.
What are the available feeding mechanisms?
Many types of feeders have been designed some of which are apron, belt, chain, roller, rotary, revolving disc, and vibrating feeders.
What is Chain-feeder and how it work?
Chain feeder consists of a curtain of heavy loops of chain, lying on the ore at the outfall of the bin at approximately the angle of repose. The rate of feed is controlled automatically or manually by the chain sprocket drive such that when the loops of chain move, the ore on which they rest begins to slide.
What is elliptical bar feeder and how it works?
The elliptical bar feeder consists of elliptical bars of steel which form the bottom of a receiving hopper and are set with the long axes of the ellipses in alternate vertical and horizontal positions. Material is dumped directly onto the bars which rotate in the same direction, all at the same time, so that the spacing remains constant. As one turns down, the succeeding one turns up, imparting a rocking, tumbling motion to the load. This works loose the fines, which sift through the load directly on to a conveyor belt, while the oversize is moved forward to deliver to the crusher. This type of feeder is probably better suited to handling high clay or wet materials such as laterite, rather than hard, abrasive ores.
What is apron feeder and how it works?
The apron feeder is one of the most widely used feeders for handling coarse ore, especially jaw crusher feed. It is ruggedly constructed, consisting of a series of high carbon or manganese steel pans, bolted to strands of heavy-duty chain, which run on steel sprockets. The rate of discharge is controlled by varying the speed or by varying the height of the ribbon of ore by means of an adjustable gate.
What is belt feeder and how it works?
Belt feeders are essentially short belt conveyors, used to control the discharge of material from inclined chutes. They frequently replace apron feeders for fine ore and are increasingly being used to handle coarse, primary crushed ore. They require less installation height, cost substantially less, and can be operated at higher speeds than apron feeders.
What is vibrating feeder and how it works?
While feeding primary crushers it is necessary to segregate the coarse and the fines so that “packing of the crushing chamber” is avoided. Otherwise if there is not sufficient space for the crushed ore to expand in volume, choking of the crusher is possible. Hence vibrating grizzly feeder preceding the crusher removes the fines and undersize and at the same time also regulates the feed to the crusher.