Asphalt Mixing Plants For Flexible Pavement Roads

 

Shashank Agarwala

Director-International Sales
Speedcrafts Limited

 

Over the past few years India has witnessed spurt in demand for Road Construction Equipment moving northwards led by unfolding of huge quantum of road construction and infrastructure projects. While the speed of road building is of utmost importance, the quality of roads is also not be compromised and should be in line with global standards. This dual objective of quality and speed can be achieved only by deploying road construction equipment of the latest technology. Asphalt Plants is a crucial equipment and is a pivot around which flexible pavement projects revolve. Globally, Asphalt Mixing Plants are classified into two broad types – Drum Type Continuous Asphalt Plants, more popular in North America, can deliver quality mix only if the input quality of the aggregates is in conformity with mix design, whereas Batch Type Asphalt Plants that are popular in other parts of the world including India addresses this issue by secondary gradation i.e., screening of aggregates and measuring each ingredient of the mix including bitumen and filler by weight rather than by volume. Recognising this feature of measurement after screening and de-moisturizing in Batch Type Asphalt Plants, the Government authorities in India like MoRTH and NHAI have made it mandatory to use Batch Type Asphalt Plants in almost all major projects of Central and State Governments.

 

 

SPEEDCRAFTS - a leading Indian manufacturer of Batch Type Asphalt Mixing Plants with worldwide supplies to over 60 countries sourced design and technical know-how from Europe and clubbed it with localisation and manufacturing expertise which led to evolvement of European Standard Plants with optimum prices. Core components, which are extremely important for quality of mix and reliability of operation, are sourced from globally renowned suppliers whereas brain of the plant - control software – developed in collaboration with European partners uses software from Europe and hardware from India.

General Configuration Of The Plant

 

 

Cold Feed Bins

These bins channelize the supply of different sizes of cold aggregates to Inclined Conveyors for feeding it into Dryer Drum for de-moisturising and heating. These are modular in design and have self-relieving bottom opening to eliminate bridging of aggregates in feeders. Each bin has its own feeding conveyor, which is driven by variable speed inverter drive through gear box and motor. Variable drive is provided as first-hand control to feed different sizes of aggregates as per mix recipe. Aggregates get discharged onto gathering / collecting conveyor, which is designed for collecting and transferring the aggregates to inclined conveyor for feeding into Dryer Drum.

Counter Flow Dryer Drum

This is a major component of plant meant for drying and heating of aggregate to ensure minimum residual moisture content in aggegates. It is fitted at one end with modulating burner, which generates required heat energy for drying process. The flights inside the dryer are designed to expose the maximum surface area of aggregates to burner flame for maximising the energy utilisation and optimising fuel consumption.

Modulating Burner

Our modulating burner is a low noise multi-fuel burner with choices of diesel, LDO, heavy oil or natural gas. It is provided with servo motor for air regulation and PID controller for modulation.

Bucket Elevator

Bucket elevator housing several buckets lifts and transfer the heated aggregates received from Dryer Drum to Multi Deck Vibrating Screen.

Multi Deck Vibratory Screen

Our Multi Deck Vibratory Screen is based on Inclined Circular Vibration Technology for efficient screening of dried aggregates and separates aggregates as per mix recipe. High efficiency and low wear cost are the features of our screen.

Hot Bins

These are compartments below the screen, which stores the segregated aggregates as per mix recipe and ensures seamless supply of all the required sizes of aggregates in the mix to ensure smooth and optimum operation of the plant at rated capacity.

 

 

Weighing Bin /Buckets

Separate bins / buckets of adequate capacities for aggregate, filler and bitumen is provided, which is mounted on load cells for real time control of weighing process one by one by PLC based control system and ensure precise weighing to adhere to mix design quality requirements. Design of discharge gates with respect to mixer ensures fast discharge and shorter mixing time for high productivity.

Twin Shaft Pug Mill Mixer

Adequately sized twin shaft mixers are fitted with paddle mixing arms, which gives peripheral and gravity acceleration to material inside the mixer to ensure homogenous mix in optimum time to minimise oxidation of asphalt / bitumen. Smooth flow discharge gate ensures fast discharge of material with least segregation and minimum batch cycle time to increase productivity.

Bag House Filter System

Bag House Filters remove the dust from the Dryer’s exhaust and comply with the most severe environmental regulations. It is having sufficiently large filtration area, temperature resistant fabric of bags, aluminium cages, efficient and reliable design of reverse air flow cleaning mechanism consuming less power.

Hot Mix Storage Bin

Our plant is provided with in line hot mix storage bin beneath pug mill mixer. This bin ensures buffer storage and faster truck filling and avoids intermittent operation of plant.

Control System

Computerised PLC based control system is provided for burner, temperature, damper, emergency plant shut down, sequential start and stop, etc. It has real time control of important process parameters, unlimited recipe storage, easily configurable logic controls, proven and most reliable software. Remote connectivity is provided for remote assistance and control from headquarter to any plant location in world to provide reports on all important aspects of the plant operation and process control.

 

For more information, visit: www.speedcrafts.com