Cost savings through elevator overhaul
Spaansen Bouwsystemen in Harlingen has achieved significant cost savings with the complete overhaul of its elevator. Besides a more efficient method of processing, the mechanical systems are now equipped with long lasting, durable components.
Spaansen Bouwsystemen in Harlingen produces precast concrete structures. An essential conveyor in the production process is the belt elevator, which processes raw materials such as sand and gravel to the concrete mix plant. An extensive inspection by the Muller Beltex team revealed that this elevator was not sufficiently reliable. Over time, the abrasive minerals had caused a lot of wear and fouling, which meant that the continuity of providing the plant with raw materials could no longer be guaranteed.
The investigation learned that both the drive pulley and the return pulley had to be replaced. This operation has been carried out not just substituting components but by implementing notable improvements, increasing the durability of the elevator. The return pulley (lower drum) has been replaced by an open wing pulley with cone in the middle. Because of the wings and cone, product getting stuck between the elevator belt and the pulley is better taken out. Less contamination reduces the wear of the belt, especially the belt joint.
The drive pulley and its lagging were in poor condition. The pulley was sensitive to contamination and gave rise to belt misalignment. Muller Beltex installed a new pulley equipped with an interchangeable Slide-lag. This lagging gives a firm grip on the belt and, thanks to a unique ‘winter tire’ profile, removes dirt well. The lagging protects the pulley from wear. It can be replaced without disassembling the pulley. The bearings were also replaced and a new weather-resistant SEW drive was installed.
The elevator buckets had become thin due to wear and began cracking. In course of time wet product had corroded the bolts and nuts. This allowed buckets to get loose, resulting in loss of capacity and damage to the installation. On the new elevator belt Muller Beltex mounted Maxi-Lift’s robust Nylon Tiger-Tuff elevator buckets. Unique rubber filler plates between the buckets and the belt prevents product getting caught in between, avoiding damage to the belt. Every tenth buckets has a Hardox scoop rim. The Hardox edge offers extra protection when grabbing product remaining at the bottom of the elevator foot. It also prevents the wear of the Nylon scoop edges of the other buckets.
The rubber elevator belt has been made endless with the new Maxi-Splice belt fasteners. These clamping devices have a rubber, adjustable rear protection plate that prevents premature belt wear, offering more security with two M20 fasteners. In addition, the elevator is equipped with stainless steel Rub-Block sensors. These sensors detect belt misalignment, based on a continuous temperature measurement with a PT100. In case of misalignment, the belt friction on the Rub-Block causes an immediate increased temperature measured by the PT100 in a brass plate and that is observed in a PLC. A pre-alarm (e.g. already at > 45°C) and a stop alarm (e.g. at 90°C) can be programmed in the PLC. In the event of a stop alarm, the installation immediately shuts down so action can be taken to correct malfunction. This feature prevents or minimizes damage of the system.
With the quality components Muller Beltex selected for the overhaul of the elevator, a stop alarm is unlikely to occur. Consequently Spaansen Bouwsystemen can depend on a reliable and robust system that more than justifies the investment in the continuity of the manufacturing process.