Normal and reverse circulation drill

The forward and reverse circulation integrated rig can switch between forward and reverse circulation at will, and a pile can switch between forward and reverse circulation multiple times in complex formations. Using frequency converter and frequency conversion motor, the drilling speed has 80 speeds. It can be adjusted freely between 1-80 rpm according to the pore size and the softness of the formation.

6"（ZFJ-1500）Normal and reverse circulation drill

 8"（ZFJ-2000）Normal and reverse circulation drill

10"（ZFJ-2500）Normal and reverse circulation drill

ZFJ-2500 drill is a normal and reverse circulation drill, which is composed of YD multi-change speed motor, gear reducer, normal and reverse circulation mud pump, valve, hydraulic pump, oil cylinder, main winch, auxiliary winch, distributor box, drilling cramp, pipe and drill bit.

II. Drill Structure：

1. The main motor is YD multi-speed motor, and the rest motors are common Y-series motors.

2. The gear reducer adopts four-axis three-stage gear reduction combined with an inverter motor, which can perform 0-120 Hz transformation to achieve the purpose of variable speed. The spindle speed can be changed according to the construction diameter and formation.

III. Operating Principle of Normal and Reverse Circulation Drill

1. The oil pressure system of drill is controlled by the oil pump through pipelines and multi-way valves and then arrives at each actuating mechanism to complete various actions as required.

2. The gear reducer transfers the power to the output shaft through a speed transmission to drive the drill pipe and drill bit to perform normal circulation (clockwise) to cut work (reverse circulation is used for removing drill pipe). Reverse circulation is prohibited in normal drilling (the reverse circulation will cause the drill pipe dropping and drill bit accident).

3. Normal and Reverse Drill Operation

3.1 During the operation, if the drill bit needs to be replaced due to the layers or well flushing, take normal circulation drill as an example: operate hydraulic handle to close the large mud pump valve, open small 3PNL mud pump, flush water through pipelines and large pump drill pipe into the bottom of drill tip, carry away the mud residue in the hole through well pipe to the sedimentation basin, the water after precipitation flows into 3PNL mud pump again.

For reverse circulation method, rotate the main unit, close large pump valve, start 3PNL slurry pump, prime large slurry pump, exhaust the air empty, start the large slurry pump, open the valve at the same time, close the 3PNL slurry pump, and the equipment can work normally when the large pump flows water as normal (if there is air or leakage in the drill pipe, the water output of large pump will be affected). The normal and reverse circulation can be changed at any time, at the same time the reverse circulation can clean the holes after completing normal circulation drilling (remove sediment).

3.2 Cage Placement and Grouting 

After completing pile hole, lift drill pipe and drill bit, and move the drill backward at the same time to an appropriate position (depend on the secondary forehead hook on the frame align with the center of pile hole). The winch can be placed and grouting commercial lime at the same time.

IV. Safety Regulations for Normal and Reverse Drill Operations

1. The drill operator must be trained, and familiar with the operating mechanism and safe operation procedures. It is strictly prohibited to operate after drinking.

2. Before operating, the drill and auxiliary equipment should be inspected. Particularly, attention should be paid to check whether the brake of each winch is flexible and reliable, and whether the steel wire rope is broken. The machine can be started after being confirmed to be in good condition.

3. The field personnel must wear insulating shoes and safety helmet.

4. When disassembling and assembling drill pipe, operator should concentrate and remove foreign matters on the thread of drill pipe in time. Adding some oil can reduce the damage and leakage of drill pipe.

5. Operators should comply with the handover system, and should make clear to the successor the working conditions and hidden dangers of drill. The equipment should be operated after dealing with abnormalities. 

V. Usage and Maintenance of Normal and Reverse Circulation Drill

1. Check the winch oil level of main machine frequently, add and replace oil regularly, and inject oil into the winch pipe. 

2. Note that the large pump cannot be reversed when connecting to the field power. 

3. During operating, monitor the electrical instruments at any time, listen to the operating parts, and stop machine for inspection in case of sudden abnormal sound; the equipment should not be performed under failure condition. Fasteners should not be loose.

4. The hydraulic handle should be operated slowly and then quickly (depend on the actual conditions). Fast operation will damage the equipment and raise dangerous situations.

5. The drilling speed varies according to different layers, depending on the water condition of pump (the speed can be increase for large water flow, but should be reduced or stopped for small water flow), and the mud weight should be controlled to drill slowly within the rated current range.

6. Check whether the oil pipe and joints leak frequently, such as leakage and creeping phenomenon.

7. All cylinders should be recovered or covered with rust resisting oil to prevent rust and damage when the drill is out of service for a long time.

8. The drill should be maintained when the cumulative footage reaches 5 km.

VI. Electrical Distribution System

1. The distributor box is a supporting equipment of ZFJ-1500 drill, which is suitable for 380V rated voltage, 80 HZ frequency and three-phase AC power supply network.

2. Operating Conditions

A. The air temperature should be less than 85%

B. The altitude should not lower than 1000 meters

C. The voltage fluctuation should not be greater than -5%--+5%

3. The cabinet adopts outdoor-type structure, and the inlet-outlet lines are set at the bottom.

After connecting to the field power supply, the equipment can be operated normally after closing the control button of leakage protection switch (after confirming the rotation direction of motor).