Problem solving

Silo vacuum unit in limestone works

Production waste is returned to the production process

Limestone is one of the most widely used building materials. It is relatively easy to prepare. Quartz sand and lime are mixed and this homogenous mix is then pressed and heated into the desired shape.

Operators of this type of plant have must implement efficient dust control measures to keep this fine grain material out of machinery mechanisms. Limestone dust is abrasive and can cause operating faults and damage to machinery. The drive motors of the mixing equipment are particularly susceptible to this type of problem.

The Kalksandsteinwerk-Limestone works in Bautzen has solved the problem very efficiently. It has installed a Ruwac silo vacuum unit which the operator uses to keep the mixing tower dust-free and efficient.

It should be noted that the dust vacuumed up by the unit is not dirt but simply limestone-quartz dust from the production process which can quite easily be used again. In the silo suction unit Ruwac has incorporated a 280-litre container which is used to collect the dust and return it to the production process.

The mixing silo has a pipeline with extraction points. Reed valves with flap covers switch on the vacuum unit whenever the operator connects up the suction hose.
The pipeline is connected to the vacuum unit silo container. When the container is completely full
the vacuum unit stops. The bottom end of the container has a emptying hose closed off by a butterfly valve. When the operator opens the butterfly valve, the waste dust is fed into the reactor and thus returned to the production cycle.

The silo vacuum consists of components taken from Ruwac's range of modular units. The vacuum has a Class C bag filter to ZH 1/487 standard with a total filtering surface area of 4.5 m². The filter is dedusted using a hand shaker.

The vacuum is wall-mounted in a space-saving position alongside the mixing silo, ready for use at any time. For Kalksandsteinwerk, Bautzen this has two advantages. First, the silo area can be kept really clean and free of all the dust build-up that often leads to machinery faults. Second, the rate of product utilisation is greater because the dust vacuum up is returned to the production cycle. Dust emissions are greatly reduced and this is good for the environment, too.