(Weingarten, Germany) — After 16 months of rigorous service, the cement industry leader, Holcim Ltd., has experienced a very positive result with a DuroProtect® 5 rotary valve supplied by Coperion GmbH, Weingarten/Germany, installed in a cement conveying system.
The rotary valve has by far exceeded the expectations set by Holcim. The DuroProtect® 5 rotary valve has a ceramic lined housing with tungsten carbide welded rotor. This valve was installed at Holcim’s Merone, Italy, facilities in October 2009 as a replacement for a screw pump feeding a conveying system at 130 tons/hour and backpressure of 0.7 to 1 bar.
The Coperion Competence Center Materials Handling (formerly Waeschle) has developed wear-protected, heavy-duty rotary valves for a wide range of abrasive bulk materials. In Holcim’s experience the rotary valve has reduced downtime but has also saved energy and maintenance cost significantly. The pay back period in this case was nine months. The influencing factors were:
- Reduction in energy consumption by over 95% – the installed power required for this rotary valve was 5.5 kW instead of the 200 kW for the screw pump. This resulted in a significant savings of over 100,000 euro’s/year.
- Maintenance cost – there was no refurbishing of the rotary valve housing or the rotor required. Even the seals and bearings were not replaced. An additional savings of 30,000 euros/year were achieved.
Mr. Lucas Tamanini, Maintenance Engineer at Holcim, Merone, sums up the company’s experiences with the upgraded pneumatic conveying system as follows: “We ourselves were surprised by the results obtained with the wear-protected rotary valve.
Following our positive experiences with its practical application we have now ordered a second rotary valve, which will replace the screw pump of another pneumatic conveying system.”
In addition, since 2006 Holcim has been operating the Coperion rotary valves for pneumatic conveying of coal and petroleum coke. In these applications as well, Coperion supplied rotary valves with a wear protection DuroProtect, which have yet to show wear after 20,000 operating hours.
For coal and solid fuel conveying systems, the Coperion DuroProtect rotary valves offer an additional benefit. Due to the low rotor tip speed of less than 1 m/sec., the rotary valve is not a potential source of ignition. Additionally, it does not increase the fuels’ temperature, unlike the screw pump. The rotary valve can also be used for ATEX zone isolation, for example, of a silo and a conveying system for solid fuels.
Besides these cases described above, the wear-protected rotary valves DuroProtect from Coperion have proven themselves in countless applications in the minerals industry.
By Steve Broes