Problem solving

Cost-effect disposal of milling waste, chips and shavings

Customised extraction plant for pipe making

How do you remove milling waste and shavings from a pipe which has just been manufactured?

Over the years, V&M Deutschland GmbH has tried various answers to this question. The company produces seamless pipes in a large variety of diameters at its Zeithain pipe rolling mill in Riesa. Originally, the company tried tipping the pipes at an angle so that waste fell out under the force of gravity. This solution was ineffective. The next try was blowing out the pipes with compressed air. This was costly. Compressed air is an expensive source of energy and cleaning the pipes in this way also produced a lot of dirt in the surroundings. Next, V&M, working in collaboration with Ruwac Industrie-Sauger GmbH, developed a customised extraction plant and since then has never looked back. The plant meets all the company's quality and efficiency specifications.

At the Zeithain works, the cross-cut pipes are laid out in piles up to 800 wide; piles can contain up to 42 pipes depending on pipe diameter. The piles are fed along a conveyor to a purpose-built extractor adapter which looks something like an oversized suction attachment on a vacuum cleaner. The pipes are fully closed and sealed on one end by two heat-resistant, hollow edge seals.

When the suction attachment is connected up, the extraction plant switches on automatically and the chippings and shavings inside the pipe are sucked out. The extraction process is aided by a shaker device which loosens and detaches the chippings from the pipe surfaces. The vacuum power developed by the plant varies according to the diameter of the pipe currently being processed. Ruwac engineers have programmed the plant so that there is a vacuum power setting for each pipe size. The operator just enters the current pipe size and the plant PLC then automatically adjusts the vacuum setting accordingly.

This extractor plant uses three side-channel blowers and a high-pressure fan to ensure that sufficient air speed is created inside the pipe. Compressors have an individual rating of 25 kW while the fan has a rating of 23 kW. The maximum flow rate developed is 10,000 m³/h.

The solid particles in the air flow are separated out by six filter cartridges each with a filtering surface area of 28 m². The filter fold angle has been designed specifically for this application to ensure optimum cleaning. Filter cleaning/dedusting is automatic. At a programmed differential pressure the controller triggers the system which cleans the filter with a counter-flow of compressed air.

The particles from the filters are fed to a bunker. The bottom of the bunker has a double pendulum flap; this operates continuously and feeds the waste onto a waste conveyor. If waste inside the bunker exceeds a programmed level, a sensor triggers a warning signal.

The unit installed by Ruwac at Vallourec serves two transfer stations. V&M's experience with this system has been so positive that it will shortly be ordering a second extractor system to serve another two transfer stations.