| Diameter (MM) | Elements | Length (M) | Torque (KN·M) | Max Drilling Depth(M) |
| 355 | 3&4 | 8-12 | 180 | 42 |
| 377/368 | 3&4 | 8-13 | 220 | 46 |
| 406/394 | 3&4 | 8-14 | 230 | 50 |
| 419/426 | 3&4 | 8-15 | 250 | 54 |
| 440/445 | 3&4 | 8-15 | 259 | 54 |
| 470 | 3&4 | 8-17 | 280 | 62 |
| 508 | 3&4 | 10-17 | 320 | 62 |
| 530 | 3&4 | 10-20 | 380 | 71 |
| 575 | 3&4 | 10-21 | 420 | 75 |
| 630 | 3&4 | 10-21 | 460 | 75 |
| All specifications can be tailored as per customers’ special requirements. |
Kelly Bar is the key part for a Piling Rig, to make high reliable Kelly bar, we have to follow rules as below:
1. Top quality material
2. High welding quality
3. Appropriate heat treatment
4. Professional design
We can make Kelly bar for both Chinese and European brands.
How to use kelly bar?
Interlocking type kelly bar
A. Rotary table turns, keeping the drilling tools right on the hole position and making sure that kelly bar keeps vertical during the whole drilling process.
Before drilling, adjust the kelly bar and make it vertical to the ground.
B. When lowering the kelly bar down into hole, you must rotate the drive slowly to prevent the wall of hole rubbing the drilling tool and avoid sudden fall.
As interlocking kelly bar is lowering, the rotary drive should keep counter-rotating slowly;
As interlocking kelly bar is lowering, the rotary drive can not rotates along the rotation direction of kelly bar.
C. When the drilling tools reaches the bottom of the hole, further drilling can not begin until all sections of the kelly bar are locked. Operate the rotary drive to rotate slowly.
The kelly bar transfers the torque from the rotary drive to the drilling tool and makes it rotate to drill.
D. Unlocking and lifting steps:
Unlocking step one:
Life the rotary drive upward by 10-20cm. As drilling work finishes, firstly lift the rotary drive upward by 10-20cm to relieve pressure and recover the kelly bar to vertical state.
Unlocking step two:
Keep the rotary drive counter-rotating slowly and continue to lift it by 20-30cm. This is the preliminary unlocking step, and some section may be still interlocked. At this time, direct lift using hoist winch is not allowed.
Unlocking step three:
After doing step tow, keep counter-rotating the rotary drive slowly and press it down by 30-40cm. This is to fully unlock the kelly bar.
Unlocking step four:
Keep the rotary drive counter rotating slowly and use winch to lift the kelly bar until the drilling tool can be seen.
Note: The rotary drive rotates slowly in the whole lifting process. This is to avoid self interlocking of section during lifting.
At this time, operator should observe the pressure gage of the winch and lieten to how the motor power changes to judge whether there is obvious overload or not. If it is overloaded, the bar to the bottom of hole and unlock again according to the steps.
E. Lift drilling tools out of the hole and remove earth on it.
F. Circulating
