As we have stated previously, we are going to be taking the ideas developed in this column over the last couple of years and developing them into design practices. This is how it works. We will provide the basic narrative here for one design practice each week. We will keep it open for comments for one month. After that, we will finish it in formal form and offer it for sale at a modest price. Here is where you come in. If you make a substantive contribution to a standard, the organization for which you work will be granted a pro bono license to use that standard with its current issue number for as long as you like. We have had good response so far! Contribute, please.
This week's: Felted Dryer Drives with integral motor pulleys (LGM 2012.013.01 when issued)
The idea of driving dryers with felts, thus eliminating gears is not new. However, the use of hermetically sealed integral motor pulleys as felted dryer drives may be.
A motorized pulley is simply a drum motor in which the outer shell rotates around a stationary shaft, thus exhibiting significant advantages over the conventional gear system used as dryer drives on the paper machine. Benefits include: high efficiency, lower energy consumption, low maintenance, compactness and ease of installation.
To use hermetically sealed integral motor pulleys as felted dryer drives.
The motorized pulley design with components: motor, gears and bearings housed internally within a hermetically sealed rotating outer metal drum casing, ensure that the drive unit is unaffected by dust, water, oil and other harmful substances, not forgetting the lack of external moving parts improves safety considerations and eliminates potential hazards. The internal mechanism also reduces sound intensity.
The most significant advantage of motorized pulleys over the conventional drive system is efficiency. Mechanical efficiencies of up to 96% can be achieved due to lower frictional losses, thereby resulting in lower energy requirements and operating costs.
Oil inside the casing is used both as a lubricant as well as heat transfer fluid, preventing undue mechanical stress and the motor overheating, extending service life, and allows for operation in more severe environments (up to 120 degrees F).
Maintenance is reduced to periodic oil changes every 50,000 operating hours, and oil seal changes every 30,000 operating hours.
1. The Rulmeca Group
So, give us your comments by 27 Feb 13, please!
Still open for comments Fabric Roofs (Open until 20 Feb 13)
Still open for comments CPVC Dryer Bearing Drains (Open until 13 Feb 13)
Still open for comments Foundation Design Practice. (Open until 6 Feb 13)
As always, your comments will be appreciated.
Brian Brogdon, Ph.D.
Send us your comments!