TRANSPORT, SCREENING AND GRINDING

Mechanical conveyors are often taken for granted, as their performance characteristics are seemingly obvious and simple. This is not the case because choosing a conveyor entails a deep knowledge of the fundamental laws of mechanics and the basic flow properties of the bulk material being conveyed. We design, manufacture and install conveying lines for bulk materials made up of belt conveyors, vibrating conveyors, bucket elevators, screw conveyors, standard chain conveyors and special chain conveyors for all industrial processes.

Conveying lines are always "tailor made products" that require a specific design and conception. From deciding on size, layout, design and interconnectivity between the machines, we then install and start-up the transport line.

We use many different systems to sieve bulk materials and obtain classification of grain size. Depending on the material, its size and the type of selection required, we choose, together with the customer, the most suitable machines: vibrating screens, rotary screens, resonance screens, tumbler screens.

We design, build and install screening machinery equipped with all necessary accessories like support structures for conveyors and machines,
de-dusting systems if necessary, catwalks and last but not least the connections between machines.

It is important to remember that the connections between machines play a fundamental role in the functioning of the plants.
If just one connection is not well designed the correct functioning of the entire system, in terms of productivity and reliability, is compromised.

Grinding is necessary to transform inert materials into fine sands or powders.
In order to obtain sands, we employ impact mills (with a horizontal or vertical axis), whereas we use roller mills joined to wind separators to obtain powders. In the wind separators, the classifying of fine powders is carried out by an upward air stream, flowing at a controlled speed.

The air stream carries only those particles that are only a few dozen microns wide.
With Bag filters or cyclones we separate powders, which in this case are a product and not a pollutant, from the air stream.

Bucket elevators

In order to lift bulk materials vertically, we use bucket elevators providing the pieces are not too large.
After analysing the characteristics of the material, we design, manufacture and install bucket elevators to lift all kinds of liftable products in bulk.
The buckets are mounted in the elevator at regular distance, on chains or rubber belts.
The buckets are loaded in part directly from the feeding chute and in part by the buckets dredging the elevator pit.

Material discharge occurs either due to a centrifugal force or by gravity in the case of finer and lighter materials.
The shape of the buckets, the distance between them and the speed of the conveyor are decisive for the material to be discharged regularly
and not to reduce the conveyor’s efficiency and therefore decrease its expected hourly capacity.

We must, in fact, ensure that the material goes into the discharge chute and prevent it from falling into the elevator shaft
which would lead not only to a decrease in the hourly flow but would also cause the buckets and shaft to become worn more quickly.
In order to avoid this, it’s necessary to ensure that the transported material, coming out of the bucket, doesn't hit the bottom of the bucket
in front of it or that it does not fall out due to excessive centrifugal force.

Vibrating conveyors

Vibrating conveyors are machines, which consist in a steel trough supported by elastic elements and driven by one or more vibrators.
The vibrators generate reciprocating oscillations, which cause products to advance within the trough.

The conveying trough may be open where the product is visible, or closed where the product is isolated from the external environment
and thus dust dispersion is avoided. The peculiarities of any transport system for products in bulk, makes it necessary to design,
manufacture and install vibrating conveyors of an appropriate shape and length for the transporting system required.
Moreover with the parametric design in solid modelling we can design and draw a vibrating conveyor,
which responds to the needs of the client just a few hours after the request has been made.

We can conceive and produce vibrating conveyors supported by the weight-bearing structure or hanging from it,
with the vibrators above or below the trough. If necessary, we can line the Inside of the trough with plates
of wear-resistant material or plates with a low friction coefficient.

 

Vibrating screens

Vibrating Screens are used to separate materials into various sizes for further processing, or for end use.

This machine is widely used for sieving bulk materials, in order to obtain classification of grain size.
Vibrating screens can be single-deck or multiple-deck, and they can operate dry or wet.
On each screening deck there is a grid with holes of a fixed diameter to obtain separation according to size.

After setting the operational parameters, i.e. material kind and its particle size distribution, hourly flow rate of input product,
output product characteristics, (i.e. number of different sizes required and the range for each size into which the input product is to be separated),
we calculate the hourly flow rate of each output product size and establish the main dimensions of the vibrating screen.
Once the designing of vibrating screen has been made, together with the customer, we choose the machine supplier.

With the real dimensions of the vibrating screen, we design the supporting structure, the loading chute, and the lower and frontal hoppers.
With the final detailed design of each component, we arrange for their construction and finally we install the vibrating screen.

Grinding

It is often necessary to reduce many materials to sand or powder; in this case we use the technique of grinding.
Grinding can be carried out by roller mills or by hammer mills. In the first case grinding is obtained when the material is crushed
between opposing rollers, in the second case the material is impacted by rotating hammers against hard and wearproof steel plates.

The separation and classification of powders, when they must be exceptionally fine, can be carried out by controlled air flows inside wind separators.
In wind separators, fine powder classification is carried out by an upward air stream,
which carries with it only those particles that have a diameter of a few dozen microns.

The powder separation by air is obtained through cyclones or bag filters depending on the desired powder size.