Application of the Month
Driving Waste Water Treatment
July, 2009 - View all Application Examples
The Blob, the creature from the Black Lagoon, and other frightful apparitions come to mind when considering what may lurk in the sludge of waste water. But treating this vile mixture is not as scary as it may seem.
The treatment of waste water is an important and integral endeavor in the supply and maintenance of a clean water system. Recycling water eases the demand on natural reserves.
A customer of ours, who is a manufacturer of waste water treatment plants, was in the process of upgrading the treatment facilities of a major metropolitan area. There was a need to replace the drive system that operated the sludge scrapers and collectors in the preliminary containment tanks.
This was basically a brute power application that required high reliability and long service life, but had to fit within a specific budgetary constraint. Enough service factor was required in the drive system to overcome the variable loading experienced with different sludge consistencies and content.
The design was to include a primary power source that would operate two collectors that were chain driven off a jack shaft, which then connected to a bevel box, which in turn operated a third collector mechanism. Both the sprocket and coupling connections were to have integrated torque limiters as safety devices to protect the drive components in the event of a jam up.
For the main power source a WATT drive inline helical gear motor was offered. With an operating capacity of 50,000 inch pounds, and peak torque of twice that amount, this gear motor had sufficient power to drive all the collector elements and the variable loads they would see. This unit was to be used on two sizes of collectors to standardize the main drive for both.
The helical gear motor output was connected to a bearing supported jack shaft that held two drive sprockets. The sprockets actuated two lateral sludge collectors. The other end of the jack shaft was connected to the input of a 1:2 spiral bevel gear box. With a high ratio of 1200:1 in the main helical box, the output of the bevel box would be operating at only about 3 rpm. Because of the slow speed we were able to grease fill the gearbox for lifetime lubrication. And by upgrading the bearings we were able to increase the torque capacity, thereby offering a smaller and more cost effective solution. With two sizes of collectors required we offered bevel boxes with capacities of 10,000 and 22,000 inch pounds respectively, to meet the torque demands and service factors specified.
Integral sprocket hub and coupling torque limiters were also offered to protect the drive components in case one of the collectors jammed. If this were to happen all the main power torque would go directly to the jammed device causing severe damage. The torque limiters allowed the selection of smaller bevel and chain drives, as they would no longer have to withstand a major power surge. This further reduced the system cost and potential downtime resulting from component failure.
A prime advantage of using DieQua as a supplier is our ability to supply multiple drive components for a complete system design. Our expertise at integrating these components came in handy when we caught a miscalculation of the torque requirements supplied by our customer. Our consultative approach proved extremely valuable in selecting the proper products for this tough job.
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