New
Shaft-Mounted Gear Drives Speed Production at "Fast Feed" Company
NOEL, MO -- Hudson Protein is in the fast feed business. The pet
food ingredient company produces more than 1.0 million pounds of
feed a week from poultry by-products in a process that demands
speed and reliability from employees and equipment alike. As such,
when equipment goes down, it must be replaced immediately.
The company explored several ways of increasing horsepower and gradually starting the
conveyor to reduce the damaging effects of belt slippage and over-torqued motors. They
looked at soft-start options including fluid couplings, soft start starters and wound
rotor motors. Eventually, Drummond settled on a system incorporating fluid couplings
and dual conveyor drives. "Soft start is very important if you want to keep your belt
together and you want your motors to last," notes Chetopa's Chief Electrician Bill
Kosmus.
Recently, bearing failures on a key shaft-mounted speed
reducer led Hudson Protein to explore a unique alternative to
"typical" shaft-mounted drives as a replacement. A Falk Quadrive®
shaft mounted speed reducer, designed around a single-taper
"Torque Assist" TA Taper® bushing, met Hudson Protein's challenge
for fast installation and removal.
"The bearings kept going bad on the old speed reducer," says
Hudson Protein Maintenance Supervisor Russell Waymack. "If we lose
a gear box on a cooker, we get behind real quick. If we can't
cook, we can't run."
The ailing shaft-mounted drive was a key component on one of
Hudson's seven batch cookers. The 5'x 14' cookers handle 6,000 to
9,000 pounds of feathers or meat for about two hours at
temperatures up to 270?F degrees. It is then pressed into feed and
cooled before shipment to blending mills and pet food
manufacturers around the country.
Installation of the drive is dramatically different from past
designs. With the bushing in place on the shaft, the speed
reducer's tapered bore is moved into place over the bushing and a
threaded nut and set screw tightened. The bushing design evenly
draws the speed reducer onto the shaft.
Previously, Hudson Protein used shaft-mounted speed reducers
with a twin-taper bushing design. During installation, inboard and
outboard bushings must be aligned with the shaft and unit keyways.
Bushing fasteners are alternately tightened (like lugs on an
automobile wheel) into threaded holes in the reducer's backup
plate; then torqued to specifications. If unevenly torqued,
binding and wobbling can occur.
Maintenance Leadman Bob Ballard appreciates the simple
installation of the single-taper design. "Installation was a lot
easier with the torque assist bushing than with the twin-taper
design," he says. "There aren't as many parts and the single,
threaded-taper was easy to use."
Importance of Uptime
Fast installation shortens downtime, which is important in an
operation that runs 24 hours a day up to six days a week. Because,
in addition to keeping production output high, Hudson Protein
crews also need to be concerned with incoming poultry. Hudson's
food division, located in an adjacent building, continually ships
raw poultry products 16 hours a day, five days a week.
Says Waymack: "We've got raw material coming in from next
door all day long," Waymack adds. "Just because we lose a speed
reducer doesn't mean the shipments are going to stop. We've got to
process it as soon as it comes in or it will spoil. It is
extremely important that this reducer run."
With these concerns in mind, Neil Snyder, a representative of
power transmission distributor Motion Industries, recommended the
Falk Quadrive shaft-mounted drive with Torque Assist taper bushing. The Quadrive, with 25:1 ratio, was matched with a 50 hp, 1750 rpm
motor producing 35 rpm output on the low speed side of the drive
system.
Service factor received a boost from about 1.5 to 2.5.
Service factor is a formula that combines external load dynamics,
reliability, and gear life of a speed reducer and is used to
calculate equivalent horsepower capacity. Each application has its
own conditions and operating requirements.
"We wanted a drive that gave a lot of service and was easily
serviceable," notes Waymack. "It had to be able to hold up to the
heat and torque."
Compact housings and non-complicated gearing also attracted
Waymack to the speed reducer since worn equipment, including speed
reducers, is often rebuilt to save money. "Simplicity is what we
are looking for," he says. "Time is money. If we can rebuild a
reducer quickly, that saves us money."
Harsh Environment
High service factor and easy serviceability ensure a long
life for the drive, which operates in one of Hudson Protein's
harshest applications. Located in the lower level, cooker
equipment runs in extreme heat and exposure to abrasive chemicals.
Condensation speeds equipment wear. And, variations in cooker
loads test the durability of the drive system.
Additionally, adverse conditions make bushings susceptible to
corroding and fretting to shafts in the high heat and humidity.
The design of the single-taper drive assures minimal removal
time. The bushing nut is locked in position; the v-belt drive is
removed; the high-speed shaft is rotated to develop torque which
is multiplied by the gear ratio; and the created mechanical
advantage frees the unit from the bushing taper.
Ballard finds the design offers significant time savings
during removal compared to twin-taper and straight bore designs.
"We've fought with twin-taper shaft-mounted drives a long
time to get them off the shaft," Ballard adds. "Removal isn't a
problem with the torque assist bushing design."
Twin-taper bushings present several challenges during
removal. In many cases, the threaded removal holes in the flange
can become badly corroded and strip out, requiring the bushing to
be broken with a sledge hammer. Additionally, opposed twin tapers
must be moved along the shaft out of the unit taper, a maneuver
which often proves difficult.
Extending Equipment Life
Combating the damaging conditions is no easy task. Current
maintenance programs call for routine oil checks of speed
reducers. Lubrication plays an especially important role.
"The reducer has to have the right lubricant to keep it
cool," he says.
Stack fans alleviate some of the overheating concerns and oil
filters keep lubricant clean longer, despite difficult conditions.
Most importantly, by using a unique speed reducer with better
reliability and service characteristics, Waymack has improved his
production potential as well as reduced the overall maintenance
costs. Over time, other cookers will receive the new speed
reducers.
"There is not a whole lot of maintenance needed to keep this
speed reducer running," Waymack adds. "We expect to get many good
years of operation out of this speed reducer."
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