The following procedures should be performed before the mast raising:
- unfasten the mast from the front stake and remove all things interfering with raising;
- open buckles of the mast legs fixation to the frame, check security of attachment by U-bolt to the lower girth of the kelly bar with swivel;
- make sure that the gearbox lever No.13 (Drawing 19) is set to the neutral position and rotary lever (10) is off. The lever No.11 must be on for the drawworks, the levers No.7 and 8 must be switched off. The levers No. 4 and 5 should be blocked (to prevent falling of swivel together with operating pipe); levers No. 6,9,3 must be switched off;
- open two-three turns all valves of oil dispenser;
- push the clutch pedal in the cab while the engine is working at low speed; switch on the fifth gear of the vehicle gearbox and toggle switch of transfer box. In this case all units of the drilling rig must be switched off or be at idle run; switch on the oil pump.
All the procedures must be performed when the gearbox of the rig is switched off. Make sure that the gearbox lever of the vehicle is in the neutral position afterwards switch on the oil pump of mast raising using lever No.12.
Open needle valve of pneumatic system receivers, switch vehicle transfer
gear-box to the neutral position.
If you fail to switch the cam clutch entirely then turn the rig gearbox shafts by setting the lever No.12 in the neutral position afterwards immediately switch on the vehicle gearbox and try to run up the pump one more time.
It is forbidden to stay under the mast or in the cab during raising and lowering the mast.
The engine must be properly warmed-up prior to raising the mast.
When the engine speed is 1800 min-1 the raising shall be performed in the following order:
- Close the mast lowering shutoff valve No.13 thoroughly (Drawing 10); in this case the oil supplied from the pump through the mast raising valve (10) is pumped over to the flow line. When closing the valve No.10 gradually increase the pressure in the hydraulic system till 1,5-2,0 mPa; afterwards check all the pipelines and joints of the rig.
- If the leakage or tip leakage is discovered the work should be stopped till debugging is performed. Pipe joint leakage is to be eliminated by nut tightening or by replacement of damaged ring seals.
- When closing valve No.10 try to achieve the further pressure increasing. Raising of the mast usually starts when the pressure is 3 mPa. If the pressure exceeds 5,5 mPa or the safety valve (in the dispenser; its functioning is accompanied by sharp noise) is actuated the mast raising should be stopped, the pressure should be decreased till zero, the malfunction preventing the mast raising should be eliminated.
- During the mast raise process at first the external cylinder rod (of the major diameter) raises. When it is 600-700 mm out of the hydraulic jack try to make the internal rod of the minor diameter (in the external rod) moving by screwing the mast lowering valve No.14. In case the rod doesn’t move when the valve No.14 is thoroughly screwed increase the pressure by screwing the valve No.10.
- When the internal rod is fully raised bring the mast legs to the rig by means of opening and closing the valve No.14 then fasten the legs with the buckles.
- After that screw tightly the valves No.13 and 14, decrease the engine speed and set the gearbox lever in the neutral position.
- Switch off the mast raising pump and close valve No.10 and mast raising shutoff valve No.11.
- Connect the cable of engine friction control to the pedal at the mast leg and check the operation of the engine friction control.
- Pull out jack-screw installed in the mast legs till the self-adjusting thrust bearing slightly raises the mast. This will discharge the rear vehicle spring.
- Unfasten the swivel with the kelly bar from the mast girth.
- Use the bar as the bob; turn the mast position by jack-screw (accurately to 30 mm) in relation to the axis of the rotary table orifice. When unscrewing leave at least 100 mm of screw thread in the jack nut.
Drawing 10. Jack Hydraulic System:
1 - dispenser; 2, 6, 7, 9 - conduits; 3 - unloading line; 4 - oil tank; 5 – hydraulic jack; 8 - pump; 10, 11, 13, 14 - valves; 12 - spring; 15 – manual pump
a – oil motion when lowering the mast; b - oil motion when raising the mast; c – from pump to dispenser; d - to drain