FLSmidth is dedicated to continuous improvements utilising technology to make its products more competitive. To meet the demand for pump flow and speed variation, it recently developed a solution for the Osisko Mining Corporation located near the province of Quebec. The arrangement incorporates FLSmidth’s biggest inline pump assembly to date.
This new design will be available to all FLSmidth mining pumps, slurryMAX, millMAX, or gravelMAX. The pump shaft is directly connected to a gear reducer that is connected to the automatically adjusting fluid coupling then to the motor, all precisely aligned on a common steel base. Steel bases are custom-made which enables nearly any style, brand, or different sized component mentioned. FLSmidth commonly uses FALK gear reducers, and VOITH provided the fluid coupling.
Large and strong
The size and strength of every component within the assembly contributed to this successful creation. The inline, a directly coupled configuration, has the longest common steel base allowing the entire assembly to reach a length of 30 ft (9.1m). It uses the largest gear reducer and air-to-oil cooler at 3.2 tonnes, largest shaft couplings at 740 lbs (336kg) a piece, and a 3000 HP motor. The motor alone weighs almost 26,000 lbs (11,793kg). This assembly incorporates a 2.5 tonne fluid coupling with a 9.2 ft (2.8m) heat exchanger. The final weight of the entire pump assembly is 50 tonnes.
The 28 x 26 millMAX pump is capable of pumping 36,000 gal/min (136 cu.m/min), 8000 tonnes per hour, which is the same as filling a standard 12ft x 24ft (3.65m x 7.3m) swimming pool in 18 seconds. The project called for 17 inlines to feed machinery such as Osisko’s 38-foot (8.5m) SAG mill (the largest in Canada), tertiary ball mill, and tailings and leach thickeners.
These assemblies have an assortment of instrumentation ranging from speed sensors and bearing temperature sensors to fluid level and torque output, complete with a digital display. Relevant data is communicated to the fluid coupling adjusting the speed of the pump. If the pump falls below the lowest setting, the fluid coupling will automatically adjust itself and pull more speed and torque from the motor which is translated through the gear box to the pump. It also follows the same guidelines if it runs to fast.
Vibration is dramatically reduced, since the input and output shafts within the fluid coupling spin independently which also extends the life of the motor. With the fluid coupling in place, the spike in startup torque and amps drop while serving as a type of “Soft Start” which saves energy. During operation, any surge of material felt through the pump does not affect the motor. The fluid coupling will adjust for variances in density. The independence of the output and input shafts of the fluid coupling also allows the motor to spin at continuous speed.
CONTACT: Daniel Blanco