Summary

ZL-Y series large diameter rock-penetrating hydraulic rotary head long screw drilling rig is a kind of bored pile equipment for large diameter piles which diameter is 1-1.5m and drilling depth is 20-40m. It has already been widely applied in the  cast-in-place concrete pile construction of building foundation, bridge foundation，airport foundation，roadbed of railroads and trackless roads and  all other construction of soft foundations. Due to its unique factures, it is ideal substitutes of rotary drilling dig andcirculation percussive drilling rig.

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   Main Performance　

1. It is a key product filling the domestic vacancy supported by Changsha municipal government. And owns its patented technology
2. It can bore hole which diameter reaches 1-1.5mm and which depth of rock-penetrating can reaches 1m.
3. Independent moving mechanism moves more flexible and easier especially when meet obstacles.
4. Supporting-legs-cylinder-inverted mechanism protects the piston rods from distortion.

 Advantages comparing with the electrical rotary head long screw drilling rig:

1. It can steplessly adjust the rotational speed and torque of rotary head.
2. It can protect hydraulically the electrical motor of the rotary head from damage for overload.
3. It can provide torque several times more than electrical rotary head long screw drilling rig.

Advantages comparing with rotary drilling rig：

1. Its cost is 30% lower than rotary drilling rig.
2. hole-boring speed is 20% faster than rotary drilling rig.
3. The pile is formed by filling concreteinto the hole bottom through the central pipe of the drilling pipe at the same time when the drilling pipe is pulled from the hole, so the pile-forming speed is increased by 50%.
4. It doesn’t require mud protection ,the cost construction is dropped by 10% and there is no mud pollution.

Advantages comparing with reverse circulation rotary rigs：

1. hole-boring speed is increased more than 10 times .
2. The pile is formed by filling concreteinto the hole through the central pipe of the drilling pipe at the same time when the drilling pipe is pulled from the hole, so the pile-forming speed is increased by 50%.
3. It doesn’t require mud protection, the cost construction is dropped by 10% and there is no mud pollution.

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