Development of Chain Bucket Elevator for Roller Press Re-circulation Application

Cement Plants are increasingly using Roller Press for Finish or Semi Finish grinding of Limestone and Clinker. Due to several advantages over other grinding technologies (Ball Mill, Vertical Roller Mill etc.). Roller Press is getting prominence in most of large capacity Cement producing set-ups.

Application of Roller Press typically involves several passes of the materials till required grain fineness from in-feed lumps is achieved. This requires an equipment to recirculate the materials, having handling capacity several times the finish output. The purpose is best served by employing a “Chain Bucket Elevator”.

Tsubaki, with vast experience in supply of chain bucket elevators for various applications and in-house capability to produce best quality chains was the natural choice of equipment makers for Bucket Elevator for Roller Press application.
Tsubaki started supplying elevators for roller press since 1990’s, although of smaller capacities in-tune with prevailing demand. However, soon demand for higher capacity Roller Press began to increase, which in turn propelled demand for high capacity bucket elevators for re-circulation applications.

Tsubaki carried out extensive Research and Development in this field by setting up a demonstration machine at it’s facility in Pune. With involvement of best experts from Tsubaki-Japan and India, having in-depth knowledge of elevator design and chain manufacturing, Tsubaki came up with a new series of High Capacity chain bucket elevators which would meet the industry demand for several years to come. Tsubaki aimed to design and manufacture bucket elevators reaching handling capacity of 3000 TPH and suitable for conveying heights of up to 55-60 m.

Deep understanding of materials characteristics of roller press materials was critical to development of elevator with suitable configuration. For this, Tsubaki arranged to use Re-circulation materials from actual Roller Press installation in Cement Plant to carry out several tests to determine optimum design of buckets, discharge casings and chain speed.

Typical features of Tsubaki NB Series Chain Bucket Elevators for roller press applications are :

  • Double strand chain design with side mounted buckets. Modified side link in chain is used for bucket fixing. This eliminates need of any spacers between chain and bucket, ensuring seamless transfer of motion from chain to buckets
  • Single bucket design for all capacities up to 3000 TPH. With single bucket, all problems related materials distribution are avoided. Since any diverter chute is not required in feed or discharge side, complete layout can be accommodated in lower building height, resulting substantial saving in civil costs.
  • Slow chain speed : Slow chain speed with gravity discharge mechanism ensures complete discharge of materials form bucket. Any variation in bulk density of materials, which commonly occurs in roller press applications, does not pose any difficulty for elevator operation.
  • No Re-circulation : Special design of buckets and discharge chute ensures materials discharge to onward equipment without any fall back. This prevents wear of casings, materials accumulation in boot and excess power consumption.

Tsubaki Conveyor Systems India has installed several high capacity elevators for Roller Press applications in India and abroad. Maximum demonstrated capacity is 2500 TPH (52 m Height), with designs available up to 3000 TPH.

Ash Handling System for Waste to Energy Power Plant

With rising urbanisation, efficient and environment friendly disposal of Municipal Waste is a serious issue globally. Direct combustion of waste and generation of energy in the process (Waste to Energy – WTE) is being adopted increasingly for waste disposal. Efficient and pollution free handling of Ash generated during the process is a critical requirement in WTE installations. With vast experience in Mechanical and Pneumatic handling products, TCSI is well poised to handle this challenge and is competent to design, manufacture and supply the most optimum Ash Handling System.
While designing the system, it’s important to identify the difference in properties of Ash generated from burning of municipal waste as against more commonly used mineral fuels. Special consideration is to be made for the composition of ash, resulting from various ingredients in the waste and light flow characteristics. Also, the pneumatic conveying system is designed in such way as to minimise the number of cycles per hour, leading to less wear and achieving longer life for the equipment used.

TCSI has the expertise to design heavy duty all chain type submerged ash conveyor for collecting and conveying of hot bottom ash and clinker materials from boiler bed. Conveyors with cooling arrangement can also be provided where necessary.
TCSI Design of the system ensures efficient collection of ash by employing suitable conveyors at all points and conveying the same to storage silo for further disposal. Close understanding of materials characteristics, flow patterns and possible impediments to smooth flow are critical to the design of trouble free system. Effective use of various techniques including fluidizing, vibrators, heaters etc. is made for ensuring free flow of the materials. TCSI has the skill and know-how to select and deploy the appropriate type of equipment in the storage and extraction system such as, slide gates, rotary feeders, mixers, screw conveyors and telescopic feeders.

TCSI has always believed in supplying products without compromising on quality which provide long life. Same is also reflected while designing Ash handling systems where the typical properties of ash makes these aspects much more critical for the customer.

JEL System:
Recently TCSI completed design, manufacturing and supply of Ash Handling System for Jurong Engineering Limited, Singapore for Waste to Energy plant site in Thailand. Brief description of the system is as under:

Scope : Supply of Pneumatic and Mechanical equipment and all accessories for Ash handling system for RDF fired waste to energy Power plant of 9.9 MW capacity. The system included collection of Ash from various collection points from boiler, onward conveying to storage silo, silo extraction and feeding into closed trucks for disposal.

Bottom Ash handling system –

  • Chain type conveyor with horizontal & inclined profile of size 2 mt W x 25 m L x 7 mt H to Transfer Bottom Ash to disposal yard.

Fly Ash handling system –

  • Two Chain type conveyors with horizontal + inclined profile collecting Fly ash from different ash collection hoppers and discharging ash at two intermediate buffer storage tanks.
  • Two Chain type conveyors with horizontal + vertical profile collecting Fly ash from different ash collection hoppers and discharging ash at the two tanks referred above.
  • Below the two storage tanks independent pneumatic conveying system consisting of Dome valve, Vent valve and Conveying Vessel conveying Fly Ash to 100 m³ steel storage Silo designed by TCSI.

Silo system –

  • Silo is supported on Load Cells with Bag filter for air venting. Cone portion of Silo has Electric vibrating motors and heating arrangement for assisting ash movement in silo.
  • Bottom discharge of Silo is provided with manual Slide gate and bi-direction Screw conveyor. One side outlet for feeding dry ash to closed trucks through motorised retractable chute and other side for feeding wetted ash to open trucks using a double paddle ash conditioner.

JEL Success Story

TCSI received the order around end of CY 2019. TCSI successfully carried out the design, manufacturing and pre despatch trials and completed the supplies within project timelines. All this was achieved while operating under strict limitations imposed for Covid control and making effective use of technology to work under the “New Normal”. The system has since been commissioned and under regular operation. The timing of the contract and execution proved TCSI’s capabilities to execute a critical project even under most adverse conditions

Slat Conveyor inside pit for 3 ton Tractor Assembly line & Inspection line.

Customer had requirement of Slat conveyor as below :

  • Double Strand endless chains, driven by electric motors attached with evenly spaced slats flush to floor.
  • Spare drive arrangement
  • Slat Width – 3.5 m
  • Design Capacity 3 Ton per Tractor
  • Conveyor Chain – Bearing Roller
  • Line Speed – 0.8 to 1.4 m per min
  • Length of Final Assembly Line 74 m
  • Length of Final Inspection Line 26 m
  • Nos. of Stations 15

TCSI successfully demonstrated the stress analysis & load calculation data to customer for approval during DAP. Then TCSI manufactured the system & temporarily installed at TCSI factory. After successful trials & customer inspection, it was dismantled & re-assembled at site.

First such system designed by TCSI with slats of width 3.5 m, is in satisfactory operation at customer site ensuring full capacity production of tractors.

Overhead power & free conveyor system for One ton Hood part of Earth moving equipment.

Customer had requirement of conveyor as below :
Overhead system in Paint shop.

  • TR 678 Power & free line for banking in Painting, Oven & Storage.
  • Conveyor length 356 meters with 52 hangers.
  • Hanger capacity – 1000 kgs & accumulation pitch 3.3 meters
  • Chain speed 10 meters/ min.
  • Caterpillar drive unit & Gravity take-up.

TCSI carried out detailed study of the requirement and demonstrated desired output through Cycle Time Working during design approval stage. System was manufactured and after satisfactory testing on a trial set-up was despatched to customer site. System in in operation since then to entire satisfaction of the customer.