Design Approach for Wagon Tippler for CHP of a power plant

GROUP 2Karri Krishna TejaAnku Kumar Pandey

Manglam Sharda

Contents

Introduction Components of Wagon Tippler

Platen Assembly End Rings Clamp Assembly Spill Truss Wheel Grippers and Wheel Chocks Drive Units

Working Mechanism Drawing Layout Civil Aspects Side Arm Charger

Working Principle

Introduction

Wagon tippler is a facility where the coal is unloaded from railway wagons one by one by holding and tippling the wagon upside down into hopper below.

The coal discharge from the wagon is collected in hoppers and then evacuated by APPRON feeder on to conveyors.

Wagon tippler is underground structure and is generally in rcc construction.

It is less costly in construction than track hoppers and requires less space.

The length is about 30m in contrast to track hopper which is generally 250m of above.

Components

Platen Assembly

End Rings Clamp

Assembly Counterweight Spill Truss Wheel

Grippers Wheel Chocks Drive Units

Platen Assembly

It is a fabricated steel structure frame consisting of an inner platen and an outer platen.

The inner platen is placed on top of the outer one and the weigh bridge cells are mounted between the two.

The entire platen is designed so that an Indian locomotive engine of 150T in weight can pass over it at a maximum speed of 8km/hr.

8 load cells of adequate capacity are provided in between the inner and the outer platen.

End Rings They are

fabricated steel frames of semi-circular shape.

Two end rings are connected by the spill girder, top clamp beam and counterweight box girder.

The end rings support the platen assembly, along with the loaded wagon to be tipped.

Clamp Assembly The wagon tippler is

equipped with six hydraulically-operated steel clamping arms moving through the hydraulic cylinder. 

All the clamps are designed to move into position as the wagon tippler begins to rotate, and they clamp on the top of the wagon at a pre-determined angle and hold the wagon firmly until it returns to its normal resting position, when the clamps release the wagon. 

The clamping system is designed so that it can clamp both the maximum and the minimum height of the wagon being tipped. 

Spill Truss The side supporting

beam, also known as the spill truss or spill girder, is of welded steel construction. 

It connects the two end rings and supports the loaded wagon lengthwise during operation. 

The side wall moves through hydraulic cylinders and touches the wagon standing on the platen without applying pressure.

Wheel gripper and wheel chocks Two sets of hydraulically operated wheel

grippers on the rails are fitted to the platform to grip the wagon wheels and prevent any derailing during the tippling operation.

Hydraulically operated wheel chocks on the inhaul and outhaul side of the platen prevent  the wagon wheels from rolling back on the platen.

Drive Unit The drive unit is either

electromechanical or hydraulic. 

A electromechanical drive consists of an electric motor coupled with a speed reduction gear box and brake mounted on the input shaft of the gear box. 

A hydraulic drive consists of a power pack with electric motor and a hydraulic motor coupled with a helical gear box. 

The brake is built into the hydraulic motor, and an external hydraulic thrusters brake is mounted on the input shaft of the gear box.

Working Mechanism

The loaded wagon to be discharged is placed to the central position on the tippler cradle and is weighed with Weigh Bridge (If installed).

…Contd

At rest position of the Wagon Tippler the Movable side support moves forwards and touches the side wall of the wagon gently and gets locked.

…Contd

At the start of rotation of the end rings the rail platform with loaded wagon lifts from its supports and the wagon adjusted slightly and rests against the longitudinal movable side beam.

The rotation continues and the wagon is swung towards the top of wagon.

The tippler is driven by a Hydraulic motor and the top-clamping device is actuated by four hydraulic cylinders mounted on the End Ring.

Cylinders are operated by a hydraulic power pack, which gives necessary fluid flow, and pressure to operate the cylinders.

…Contd

During the tippling operation, Top clamping device starts moving to clamp the wagon from top.

At 40 (approx) of the wagon rotation, top clamp comes in contact with the wagon's top.

At this condition cylinders get locked, in turn wagon is securely held between cradle platform and top clamp pads.

Rotation continues up to 160and material starts to discharge at 40 (approx) and continues up to 160.

After a pause of 3 sec., return cycle starts. The cradle platform with empty wagon comes to rest position.

The empty wagon is pushed out and the platform becomes ready to receive next loaded wagon.

Electrical Equipment

Feeders shall be provided from 11 kV Station Switchboards for Coal Handling Plant.

11/ 3.3kV and 11/0.433kV or 3.3/0.433kV auxiliary transformers to drive 320 kW, 1500 RPM Hydraulic (or) Electro Magnetic Motors

11kV, 3.3kV and 415V Switchgears Power and control cables including cables from 11 KV

station switchboards and 415 V unit PMCC. Cable laying along with cabling accessories, cable trays

and termination/ jointing kits of cables, and fire sealing

Side Arm Charger

Side Arm Charger is a marshalling device to position the loaded wagon centrally on tippler platform one by one for unloading operation by wagon tippler. Side Arm Charger is a rail mounted machine used to pull the loaded wagons along with the rake & push out the empty wagon from the tippler platform after tippling.

Operation The full rake of 58 wagons is brought in by locomotive and

stopped with the first wagon within range of the Side Arm Charger.

The locomotive is then taken away. The charger is driven towards the first wagon, its arm is lowered

and it is coupled to the first wagon of the rake. The charger then hauls the rake forward by one wagon length and

stopped. Here the first wagon is decoupled from the rake manually.

The charger then propels the first wagon on to the tippler table centrally and then automatically decouples and clears off the tippler.

Now the wagon tippler is ready for operation. In the meanwhile, the side arm charger is moves back to initial position for next cycle. In next cycle, the rake is drawn up by the one wagon length, and the previously tippled wagon is ejected simultaneously.

TRF Wagon Tippler with sidearm charger

TRF Side Arm Charger

Civil Aspects

Side supports for tippler

The side support shall consist of a longitudinal beam which shall be as long as the longest wagon to be tipped.

This beam maybe continuous or non-continuous.

The side support shall be articulated, so that it can take the tapered as well as parallel stanchions on the body of the wagons.

Full face contact between the side support beam and side stanchions shall be ensured.

The width of the side supports shall be sufficient to take care of the type of wagons being handled.

…Contd

Clamping arrangement Consist of a longitudinal beam or longitudinal and

transverse beams, engaging at the upper edges of the end side walls of the wagon

Self-aligning feature to bear the load on the top at each end of the wagon

Ensure that the discharge of the contents of the wagon is not impeded to any appreciable extent

Each bearing face of the beam contact the top of the wagon over a width of not less than 225 mm and are provided with rubber pads or suitable alternatives not less than 50 mm thick

…Contd

Force between the wagon tops and supporting beam is just sufficient to ensure retention of wagon and engagement of wagon wheels with the rails of the tippler throughout the tipping cycle

Take account of the nature of the material to be discharged, bearing in mind the maximum lump size, moisture content, possible climatic conditions and other influencing factors

As the frictional force between the wagon body and side supporting beams can vary widely, it shall not be taken into account in the design of the top supporting beam

The load shall be nearly equally distributed over the bearing surfaces of the beam.

Underground Aspects

Being underground structure, crack width on outer face should be restricted to 0.01 - 0.2mm and external water proofing should be provided under the foundation and sidewall.

Entire structure should be checked for safety orientation at various stages of construction.

Grade of concrete in RCC Hoppers is minimum M25 or as specified in the contract.

There shall be provision for adequate number of drain sumps at locations along with side drains with cellars for catching incidental presence of sulphurised water etc.

Sources

http://info.heylpatterson.com/blog/bid/104157/Rota-Side-Wagon-Tipplers-Handle-Bulk-Materials-for-the-Indian-Market

http://www.trf.co.in/pdf/Products/Wagon%20Tippler%20with%20Side%20Arm%20Charger.pdf

http://www.slideshare.net/lmmgroup/wagon-tippler-lmm-group

https://en.wikipedia.org/

Thank You