Screw conveyor is designed for the transport of bulk, small pieces and paste-like cargoes. The screw conveyor can be manufactured as an open version - in a trough, and closed in a pipe. The use of open screw conveyors makes it possible to control its operation anywhere..

The screw conveyor has the following design: a cylindrical body equipped at different ends with loading and unloading pipes (windows). Inside the housing, a screw is mounted on bearing supports, which is a feeding element.

The keel of the ship is one of the main structural parts of the hull. In the construction of the hull, the keel plays two leading roles - it ensures the stability of the yacht, preventing it from rolling, or capsizing, and at the same time gives the yacht's hull additional strength, in fact, serves as protection for the bottom when hitting the ground.

In modern yachting, a false keel is mistakenly called a keel - a vertical “wing” protruding from the bottom. But, since this “mistake” has long been settled, the false keel is almost everywhere, even in many official documents, called the keel of the yacht.

There are several types of keel yachts.
Ballast keel - has a weighting in the form of a metal bulb crowning its lower part. This type of keel allows you to shift the yacht's center of gravity lower to the water, increasing stability and roll resistance. Yachts equipped with a ballast keel have increased seaworthiness compared to other types of sailing boats, and also make it possible for the yacht to carry more powerful sailing equipment.

A conventional fin keel is a wing protruding from the bottom of the hull, made of wood or sheet metal. This type of sailboat keel, although less efficient than bulbous, still increases stability due to increased resistance. The resistance in this case is achieved mainly not so much due to the mass of the keel of the yacht, but due to the force of counteraction to water when the vessel rolls, acting on the flat side surface of the “fin”.

At the present time, many shipyards have come to a cast-iron-steel keel as a standard.
On the world market, steel is approximately two times cheaper than lead, and it becomes quite clear why shipyards offer steel or cast-iron-steel keels as a standard. In addition, the process of creating a lead keel is much more expensive.