The rail mounted stacker reclaimer is suitable for serving two parallel stockpile, one on either side of the track rails. The machine is designed to operate with a yard conveyor for stacking and discharging at the same end during reclaiming i.e. a reversible one.
Modes Of Operation Of Stacker Reclaimer
1. Stacking
The material on the forward moving yard conveyor is raised by the tripper and discharged through a discharge guide chute onto an intermediate inclined conveyor which lift the material and ultimately discharges on to the boom conveyor by a chute.
The boom conveyor carries the material up to its end and allow it to fall from a stockpile. The stacking operation starts at one end of the stockpile with the boom kept low. The travel motion operates simultaneously and at the other end of the stockpile, the motor reverse. After a number of such cycle the boom is luffed up and the cycle repeated.
2. Reclaming
The machine reclaims the material from the stockpile in layers by rotating bucket wheel swing across the pile. The material picked up by the bucket is retained and guided by the ring chute as the bucket moves up. When the bucket is about 45 deg above horizontal, the material starts discharging it to the bucket wheel chute, which guides it to the boom conveyor.On reaching the end of the boom conveyor, the material passes through the central chute and portal chute on to the yard conveyor belt, supported on the impact table. The reclamation of the entire stockpile can be carried out either by bench type and modular methods.
In the bench type method the reclaimer starts at one end on the top bench or layer and reclaims that bench for the full length of the pile. On the reaching the end of the pile the machine returns to the other end, the boom is lowered and reclaiming commences on the next lower bench.
The modular method is accomplished by starting at the top of the pile at one end and taking a series of cuts one bench deep end returning to the end of the pile, lowering the boom and taking the same number of cuts on the lower bench. This process is repeated up to the lowest bench thereby completing one reclaim module.
Components Of Stacker Reclaimer
1. Bucket Wheel And Drive
Stacker reclaimer Bucket wheel are used for reclaiming . The bucket wheel drive either consists of hydraulic system or motor,fluid coupling, brake and gear box, mounted on a drive frame supported by bracket. The hollow output shaft of the gear box is clamped on the drive pulley shaft through a key less shrink disc element.
2. Tripper Conveyor
The tripper raises the belt of the yard conveyor and supports it over a concave curve and discharge through guide chute on to the intermediate conveyor. After passing over the discharge pulley. The belt is guided back to the yard level over bend pulleys.
3. Boom Conveyor
The reversible boom conveyor drive is mounted on a drive frame and is supported on the revolving frame by a torque arm with plain spherical rod ends. The bearing housing supporting the discharge pulley assembly on either side are supported on sliding blocks at boom head.
The movement of the bearing blocks for the purpose of adjustment of the belt tension and the belt changing is achieved through screwed spindles. Belt sway, pull cord and belt slip monitor switches are included for protection of the conveyor. The various safety features of boom conveyor are:
- Zero Speed Switch – It is provided at the non drive pulley to monitor the pulley and thereby the belt speed and trip the conveyor motor in the event of the belt speed dropping below a preset value.
- Belt Sway Switch – It is mounted on boom on either side of the conveyor, to trip the conveyor in the event of the belt running out of the line and pressing against the rollers levers of the switches.
- Pull Cord Switch – It is provided on the support frame on either side of the conveyor, to permit tripping of the conveyor motion manually from the boom walkway in case of any emergency.
4. Intermediate Conveyor
The intermediate conveyor shall travel on the same rail as those of machine. After receiving material from tripper conveyor through vibro feeder it transfer the material to central chute during stacking operations.
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5. Boom Luffing Arrangement
The raising and lowering of the hinged bascule system and controlling it in operation, is achieved by a hydraulic system with two hydraulic cylinders. The cabin is also maintained level automatically by a hydraulic cylinder fed simultaneously from the system. The power pack also includes an independent system for actuation of the chutes etc. and is mounted on at the rear of the revolving platform.
6. Slewing Arrangement
The revolving superstructure of the stacker reclaimer is supported on a large diameter slewing bearing. An external ring gear, bolted to the revolving frame, is driven by two meshing pinions powered by two independent drive units each comprising sq. cage motor, slip clutch, brake, and planetary with bevel helical gear reducer.
The slew angle are monitored by limit switches. Additional contacts in the limit switch ensure that the boom can only be slewed over the yard conveyor after it has been raised clear of it. The safety features for the slewing arrangement are:
- Slip Clutch – It restricts the maximum torque on slew gear and thereby prevents overloading of all components and structure.
- Rotary Cam Limits Switch – It is provided to prevent slewing over yard conveyor conveyor unless boom is sufficiently raised and also prevent excessive lowering of boom over yard conveyor.
7. Long Travel Mechanism
The function of long travel mechanism is to move the stacker from one position to another position in rail track.
The various safety features of stacker reclaimer LT mechanism are:
- Travel Limit Switch – It is operated by strikers placed along the track for stopping travel at either end of pile and permits reversal.
- Automatic Rail Clamp – It is provided to drifting of the machine in storm condition. Clamps are released by hydraulic cylinders which actuate limit switches to permit travel motion.
8. Cable Reeling Drum
Preventive Maintenance Of Stacker Reclaimer Involves Following Works:
1.Checking all hydraulic hoses for any leakages.
2. Checking luffing hydraulic cylinders and tripper hydraulic cylinders for any leakage.
3. Checking all power pack and its hydraulic components for any leakages.
4. Checking for cleanliness of all components of stacker reclaimer including the hydraulic power pack.
5. Checking hydraulic oil tank for sealing and leakages.
6. checking all oil filters (Suction line, pressure line and return line) and if required replace.
7. Checking oil cooler.
8. Checking the luffing and slew hydraulic oil level in power pack tank.
9. Checking all hydraulic valves cleanness.
10. Checking the hydraulic oil condition by visualize.
11. Checking Slew and bucket drive hydraulic motor and its cleanness.
12. Checking rail clamp and mounting fasteners.
13. Checking auto lubrication system and its working condition for slew bearings and long travel wheel bearings.
14. Checking all boxes of stacker reclaimer for oil level, cleanness of breather.
15. Checking all couplings for its smooth working.
16. Checking conveyor belt joints condition and its top and bottom rubber condition.
17. Checking all idlers, pulleys, skirt rubber, scrapers, pulley bearing and coffin box condition.
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