Load section

The loading section consists of one or more silos or other storage units, organised in one or more rows, suitable for receiving any type of product. The silos are built either as monolithic structures or prefabricated and bolted together. Depending on the requirements and whether they are to be placed indoors or outdoors, they can be made of various materials. Mainly steel or stainless steel, but also painted carbon steel, fibreglass, aluminium or with an internal coating suitable for contact with foodstuffs.

The design and construction of the silos, or other containers in the loading section, is done with great attention to environmental conditions, to counteract deterioration and keep the system in full working order. These elements must also meet hygiene requirements to avoid pests and mould, and safety requirements when handling hazardous materials.

The silos can rest on supporting legs, on a long self-supporting skirt on a base, or on a short skirt or support ring on a metal structure. Other possibilities include a self-supporting skirt or support ring resting on load cells. We also provide solutions for installation in seismic or very windy areas and for sealing in case pressurisation with nitrogen or dry air is required. The silos can be equipped with:

• Safety valves
• Breather and buffer valves
• Lung hoppers
• Star valves, guillotine valves, butterfly valves on discharge
• Screw conveyor
• Fluidification
• Quick couplings for tanker loading
• Load cells
• Gravimetric load cells for product weighing
• Ventilation filters
• Loading pipes and curves, also with visual indicators
• Minimum and maximum level indicators
• Rotary, capacitive, vibration, microwave and ultrasonic level indicators
• Insulation and external coatings
• Dusting/decanting systems

Inertisation systems

Bag loading systems

Automatic/semiautomatic/manual bag cutters

Empty bag compactors

Access ladders and railings

Transfer section

It includes equipments for dosing and feeding the material into the pipeline. Depending on whether the system is in dense or dilute phase, this pneumatic conveying component can be of different types. The type also changes depending on the conditions and the material to be conveyed. For dilute phase transfer we can have:

Sucker

This is constructed with two coaxial tubes and picks up material directly from the heap, similarly to a hoover. The outermost tube allows air to reach the inlet area, so it can be placed in any position because the air arrives with the secondary flow.

Rotor or star valve

Inside its outer casing there is a device with several vanes, mounted on a rotating shaft, which define many sectors. Above this valve is the container with the material to be moved, below is the transport pipe. The material enters by gravity, fills one of the sectors and then, thanks to the rotation, the material falls into the cell, with the advantage of being easily dosed. By adjusting the rotation speed, the material flow rate is regulated. If very high pressures are involved in the pneumatic conveying system, this component is not very suitable. Air can escape upwards and material can be dispersed.

Screw conveyor

Formed by an outer shell and a worm screw on the inside, the material is transported from one side to the other by running through the helix of the screw.

By adjusting the rotation speed, the flow rate is regulated. It is a very simple system that allows dosing and heating or cooling of the material before convey.

Venturi ejector

An extremely simple device based on the Venturi effect. A pressurised motor fluid is accelerated through a restriction so that the created vacuum draws in the material to be pushed into the line. With no moving parts, this is one of the most economical and easy-to-install solutions. There are conveyors suitable for conveying many different types of materials and for a variety of industrial requirements.

Vibrating duct

Pneumatic conveying component mounted on flexible leaf springs and driven by a pneumatic/electric linear vibrator. It is suitable for fast and precise conveying of products that cannot be demixed or broken. By acting on the vibrator, very fine adjustment of the system’s flow rate can be achieved. It is suitable for conveying powdered and granulated products, even large, abrasive and delicate products, even at high temperatures. Examples are ice cream mixes, chocolate chips, dried fruit, milk powder, sugar, fresh vegetables, olives and grated cheese.

For the dense phase, the equipment in the transfer section is usually a propeller, called a transporter. This is a pressurised vessel with a capacity ranging from a few to thousands litres. The material to be moved is loaded into this propeller tank, which is then pressurised, normally between 1 and 6 bar depending on the required performance.

Once the necessary pressure is reached, the discharge valve is switched so that the material can flow down the pipe. The thrusters can also work in pairs: while one is charging, the other is conveying. This results in almost continuous dense phase transport. The equipment includes control devices and instruments such as digital pressure switches, pulsed valves, maximum level indicators, butterfly valves with actuators and limit switches, load cells.

Conveying section

This section includes piping and related components. There are different types of pipes, depending on the use to be made, rigid or flexible. Lengths, diameters and thicknesses range from small to large. Materials include stainless steel, carbon steel, rubber, PVC, polyurethane and polyethylene. We also supply them with basalt or ceramic coating to significantly increase abrasion resistance.

The various pipe sections are joined together using flanges, quick couplings, sleeves, etc. The bends can be 90°, 60°, 45°, 30° or made to measure, with a large or small radius. In order to convey the material to different destinations, we sell two-way and multi-way diverters. We have pneumatic or manual tilting barrel diverters, paddle diverters, diverters with sleeve valves, rotating drum diverters with inflatable seals, drawer diverters and stanchion diverters with butterfly valves.

Inlet section

Usually the pneumatic conveying components to the arrival section are: a silo, a hopper, a mixer, a disperser or a bag loader. In addition to the device where the material will be stowed, a more or less intensive filtering phase may also be required. The purpose is to separate the air, or the gas used for transport, from the material being transported. There are two devices for removing the material from the mixture with the air, used alone or in pairs depending on the situation.

Cyclone separator

This is a container with a cylindrical upper part and a conical lower part that squeezes downwards. The mixture arrives from the conveying duct and most of the air will be expelled from the top, while the material comes out from the bottom of the cyclone. For better separation a rotocell can be installed to act as a valve. By adjusting the rotation speed, the air is completely prevented from escaping from the bottom. The inlet pipe is tangential to the cyclone, so that the air-side mixture is directed onto the cylindrical wall. The material will then be able to crawl over it and lose velocity through friction; as it continues to slide over the wall it will progressively lose velocity and spiral down the cyclone by gravity.

It is not only friction and gravity that demixes air and material. Also contributing is the change in cross-section from the pipe to the cyclone, which causes an instantaneous drop in air velocity drastically reducing its power to support the material. The cyclone has the advantage of being inexpensive, simple, functional and without moving parts. More than one can also be installed, with batteries in series or in parallel. If the material being conveyed is very fine, the cyclone alone is not one hundred per cent effective in separating the material. The particles will tend to follow even the finest air streams, so the cyclone must be followed by a filter.

Bag filter

In terms of construction, this is a container with several tubes inside, made up of sleeves of technical filtering fabric, arranged from top to bottom. The function of these tubes is to retain the material according to a principle similar to the hoover bag used at home. The air-material mixture enters from the bottom, is forced to flow through the sleeves so that it loses particles along the outer walls of the fabric and then exits through the top.

During the operation of the pneumatic transport system these filters lose permeability due to the accumulation of particles. A fully automatic cleaning phase is then triggered. A pressure switch detects the pressure differential between the upper and lower chambers; when this value exceeds a certain threshold, the bags must be cleaned. The system flow is then interrupted and the sleeves are made to vibrate, together with compressed air being blown from the top to the bottom, so that the particles fall into a tank insulated by a roller.

Dosing section

When pneumatic conveying is used to feed weighing and dosing systems, it requires a section to divide and measure the material according to production requirements. Dosing systems range from precision (a few grams per second) to large quantities (thousands of kilograms per hour) and can be volumetric or gravity dosing, depending on whether dosing is by propellers or by weight subtraction on load cells.