Drive Units for Clarifiers and Thickeners

AshtonTucker Drive Units

Drive units from AshtonTucker are rated by the amount of torque they can produce on a continual basis for 20 years.  This differs substantially from Duty Rated Torque used by many manufacturers over the years.  (For an overview discussing Duty Rated Torque, please see http://www.ashtuck.com/blog/oil.php )  For instance, a drive that is Duty Rated for 10,000 ft-lbf will trigger a torque alarm at 30% or 3,000 ft-lbf.   Above this point, the operators are acknowledging that drive life is being diminished.  Often times, the 30% alarm level is actually the torque level where the drive is rated to last 10 years.  So a drive Duty Rated for 10,000 ft-lbf, would be somewhat comparable to a continuous rated drive at 3,000 ft-lbf.  Please keep this information in mind when comparing drive units.

 

Direct Drive – Example Model Number 10227

This drive unit supplies the torque for the clarifier or thickener, but does not offer any overturning moment capacity for unbalanced loads such as a skimmer going over a scum box.  These forces are generally assumed to be small where this drive is applied due to the use of underwater bearings or guides, or by the nature of small size of the mechanism used.

The rated torque capacity is a function of the output speed.  The faster the speed, the shorter the life, or the lower the torque rating.  While virtually any output speed can be achieved, standard speeds and torques are as shown in the table.

 

RPM

Torque [ft-lbf]

Torque [Nm]

 
 
 

0.08

3700

5050

 

0.17

3430

4650

 

0.22

3300

4500

 

0.3

3225

4375

 

0.34

3175

4300

 

0.38

3125

4250

 

PEAK

5150

7000

 

 

 

 

 

 

 

 

 Drive Unit

 

G19 – Example Model Number 10225

This drive uses a precision bearing to take overturning moments up to 40,000 ft-lbf that allows for unforeseen and unbalanced loading of the drive unit.  The torque capacity of this drive is a nominal 6,800 ft-lbf continuous for 20 year.  The rated torque is a function of the output speed as shown in the standard speeds table.  Again, virtually any speed can be achieved, with a corresponding rated output torque at that speed.

 

RPM

Torque [ft-lbf]

Torque [Nm]

 
 

0.08

6800

9250

 

0.09

6750

9150

 

0.1

6600

9000

 

0.12

6500

8850

 

0.13

6450

8750

 

0.14

6400

8650

 

PEAK

10600

14500

 

 

 D25 or G19 Drive Unit

 

G19M – Example Model Number 10237

This drive unit is the big brother to the G19.  The nominal rated torque is 10,000 ft-lbf.   The attachment of the thickener or clarifier shaft differs at this higher torque capacity.  The rated torque table is as shown below.

RPM

Torque [ft-lbf]

Torque [Nm]

 
 

0.06

10650

14450

 

0.07

10600

14350

 

0.08

10400

14100

 

0.09

10225

13850

 

0.1

10150

13750

 

0.11

10000

13600

 

PEAK

12900

17500

 

 

 Drive unit High torque

 

Cage Drive Unit – Example Model Number 10226

This is a column mounted drive unit, for use with a center cage system to transmit torque to the mechanism.  The precision bearing used allows for an overturning moment of 300,000 ft-lbf making it suitable for clarifiers up to 100 feet in diameter.  The nominal toque rating for this drive is 30,000 ft-lbf continuous for 20 years.  Like all the other drives mentioned, virtually any output speed can be achieved, however standard speeds and rated torque are as shown in the table below.

 

 

RPM

Torque [ft-lbf]

Torque [Nm]

0.028

35500

48100

0.032

35300

47800

0.038

34600

46900

0.041

34300

46500

0.046

33700

45600

0.061

32600

44200

0.089

30750

41600

PEAK

46500

63000

 

 

 Drive unit High torque

 

 

 

Comments

08/25/2017 2:12pm
These drives look great. Good Job Team AshTuck!

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