Cargotec improves the efficiency of cargo flows on land and at sea – wherever cargo is on the move, writes Conny Johanson, Product & Sales Manager at Cargotec. Cargotec’s daughter brands — Hiab, Kalmar and MacGregor — are recognized as global leaders in cargo and load handling solutions.
For dry bulk material handling, Cargotec offers well-proven, high-capacity, efficient and environmentally friendly systems under the brand name Siwertell. The Siwertell product range for bulk handling includes horizontal and vertical screw conveyors, shiploaders, ship unloaders, terminal conveyor systems and storage/reclaiming systems. Deliveries are uniquely tailored to suit each customer’s specific requirements.
To meet port environmental requirements, all Siwertell dry bulk handling systems are designed with a specific focus on sustaining environmentally friendly operation, offering totally enclosed systems that reduce dust emissions to a minimum and completely eliminate spillage.
Quality service combined with long-term support are as essential as a quality product. From the first contact and throughout the entire lifetime of an installation, Cargotec provides the services and products needed to ensure cost effective, efficient operations.
When Cargotec is requested to provide a solution for a material handling project, it is sometimes asked: “Is it really possible to install a screw conveyor for this application?” In most cases, the reply is: “Yes, of course it is!”
Siwertell (formerly known as Nordstro¨ms) screw conveyors offer flexible solutions for handling dry bulk materials. They are available in two main types; horizontal screw conveyors and vertical screw conveyors. This article highlights a number of installation possibilities for Siwertell screw conveyors from both types.
A screw conveyor can be installed at any operating angle. It is only a matter of choosing the appropriate type of conveyor.
Siwertell screw conveyors are designed to operate under harsh conditions and can handle a variety of dry bulk materials such as cement, lime, raw meal, apatite, urea, fly ash, gypsum, etc., and can be used in a wide range of installations both ashore and onboard.
  • silo/flat storage loading/reclaiming;
  • behind a ship unloader;
  • lorry/railcar loading/unloading; 
  • loading/unloading of vessels;
  • distribution/reclaiming system on board vessels and in marine terminals; and
  • mobile installations.
The screw conveyor drive motors are usually single-speed electrical motors. Two-speed motors or motors with variable speed, or using a hydraulic motor are other alternatives.
 
ENVIRONMENTALLY FRIENDLY
A screw conveyor is an environmentally friendly device as it is totally enclosed, with no spillage, hardly any dust creation and a very low level of noise.
 
VERTICAL SCREW CONVEYORS (VSC)
A vertical screw conveyor (VSC) needs only limited space. As an example, it needs much less space than is required for a bucket elevator. In most cases vertical screw conveyors involve less capital investment and installation costs than alternative systems. It remains a common misconception that a bucket elevator has to be installed for vertical transport of bulk materials. However, in a lot of cases, a screw conveyor can be a more suitable choice.
Siwertell vertical screw conveyors are able to transport material to a height of approximately 40m. If two or more conveyors are installed in a series, one feeding into the other, they can easily convey the material to any height a customer requests. For transport of even higher capacities two screw conveyors can be installed next to each other — both placed inside and loaded from the same common loading box. To date the highest capacity for one single Siwertell vertical screw conveyor is a VSC 700 (diameter 700mm) with a capacity of 1,500tph (tonnes per hour) for cement. Screw conveyors installed in ship unloaders have been delivered with capacities of up to 2,500tph.
 
Main VSC features
  • totally enclosed and environmentally friendly;
  • limited space needed for the installation;
  • specially developed long-life intermediate bearings;
  • electrically driven lubricator for automatic lubrication of the intermediate bearings;
  • single- or twin-motor drive;
  • more than one inlet possible;
  • more than one outlet possible;
  • conveying with different angles of inclination; and
  • transport of high-temperature material is possible.
Loading of Siwertell screw conveyors can be arranged in many different ways depending on the nature of a project. The graphic above left shows some inlet alternatives for loading a VSC.
The discharge part of a VSC can be arranged in different ways. The graphic at the bottom right of p80 shows alternatives with one or two outlets, with single or twin motor drive.
 
SUPPORT AND MAINTENANCE
The weight of a vertical screw conveyor is generally taken by the loading box. This means that only lateral stabilizing support is required from the inlet of the screw conveyor up to the unloading end. Alternatively, it is also possible to carry the screw conveyor weight at the unloading end if required. The specially developed intermediate bearings are easily accessible and their wearing parts are easy to change without dismantling any of the screw sections.
 
HORIZONTAL SCREW CONVEYORS (HSC)
Siwertell horizontal screw conveyors (HSC) can also be used at impressive conveying lengths. To date the longest conveying distance delivered by Cargotec is 170m, for a HSC 800 unit with a diameter of 800mm made for 800tph cement capacity. For longer distances, two or more screw conveyors are arranged in series. The Siwertell screw conveyor is equipped with one drive unit at each end.
The main features of horizontal/inclined Siwertell screw conveyors
  • totally enclosed and environmentally friendly;
  • limited space needed for installation;
  • specially developed long life intermediate bearings;
  • electrically driven lubricator for automatic lubrication of the intermediate bearings;
  • reversible conveying direction;
  • more than one inlet possible;
  • more than one outlet possible;
  • drive unit may be installed at either end or one at each end;
  • inclined and sloped conveying possible;
  • various types of drive units can be used; and
  • high temperature material transport is possible.
 
SUPPORT AND MAINTENANCE
As standard the Siwertell horizontal/inclined screw conveyor is equipped with a support at each intermediate bearing. This arrangement affords the maximum stability. If necessary the support can be customized to better fit the supporting steel structure in a building or other structure. The screw conveyor is also supported at the drive and outlet ends. The specially developed intermediate bearings are easily accessible and their wearing parts are easy to change without dismantling any of the screw sections.
 
AN EXCELLENT CHOICE
Siwertell screw conveyors are an excellent choice for conveying dry bulk materials under harsh conditions. Cargotec is able to tailor make a solution that suits virtually any type of terminal installation — a solution that is environmentally friendly, cost effective, flexible, space-effective and easily maintained.