Bitumen – Black, Sticky and Anything Else?
We are optimally connected – worldwide. Both digital and analog. Let's think of the road network. Roads are still the most important traffic routes for transporting people and goods.
A little trip back in time.
When mankind settled down, it began to build roads. For the same purpose as today: fast and convenient transportation.
Roads used to consist of several layers of gravel, which provided a stable base. However, the loose aggregates did not yet contain any binding agents.
The invention of the automobile permanently changed the way roads were constructed. Motorized vehicles churned up the top layer of gravel. This resulted in rapid erosion and heavy dust generation. Initially, the gravel layer was mixed with tar, but this is now prohibited in some countries.
Today, asphalt is bound with bitumen. The viscous black mass is obtained from petroleum and is an ideal binder due to its adhesive strength. At the same time, it ensures that the road surface is impermeable to water.
Although road construction is the main area of application for bitumen, it is by no means the only one. There are countless possible applications and areas of use. Bitumen forms the basis for products where strength and durability are required. This is because it is waterproof, resistant and suitable for use in all weather conditions.
Bitumen is a highly viscous substance that only reaches a liquid consistency under high temperatures. Temperatures of up to 280 °C may be necessary. Bitumen also occurs as a bitumen/tar mixture with different properties. Soft bitumen contains more oil components than hard bitumen.
Transporting bitumen is a challenge. The pumps must work absolutely reliably. The medium must not stagnate, cool down or solidify. Bitumen pumps must therefore be able to keep the medium hot and thus liquid. And, of course, the pump and the seal must also be designed for such high temperatures.
KRAL screw pumps can operate within a wide range of pressures and product viscosities. Our magnetic drive pumps are especially suited for this application, as standard seals can be damaged due to the high temperature and sticky nature. This is because when the seal leakage hardens, it not only requires laborious removal, but can also cause significant damage.
Before deciding which seal to use, compare the costs. Then the choice usually falls on the magnetic coupling. The more expensive initial cost is quickly amortized, because it requires little maintenance and does not need to be replaced regularly.
The pumps must be heatable. Therefore, the steel-welded, double-walled housings of our bitumen pumps are equipped with a heating jacket for highly viscous media. In addition, a high-quality ceramic bearing is used.
18.08.2021
