Tarmac – Northampton 80 mᶟ per hour skip feed wet mix concrete plant.
The challenge with this project was to replace a worn out 40 year old concrete plant with a modern 80 mᶟ per hour concrete plant which has all the up to date facilities required to operate a modern concrete plant today. The requirements were, to install the plant on a smaller footprint than the old plant while retaining certain elements of the old plant mainly the existing concrete shuttered reception hopper pit and an existing 80 tonne split silo and install additional equipment mainly an additional 60 tonne upright silo, a 30,000 litre recycled water system, a 20,000 litre fresh water tank, a larger modern welfare facility with office and a larger modern batch office with adjoining electrical room.
A new 25 tonne capacity reception with a pneumatically operated two stage discharge door, safety grid and MVE300 vibrating motor was installed on the existing shuttered concrete walls, the reception hopper feeds directly onto a radial conveyor.
The modern lattice section design radial conveyor has a chevron belt driven by a Nord geared motor unit providing the best in both efficiency and reliability. The radial conveyor is equipped with an adjustable chain driven brush belt cleaner, a rubber impact curtain in the head chute, dribble bar, plastic trays terminating in a galvanised chute and an emergency pull cord system. The radial conveyor movement area is surrounded by proximity guarding with a fortress trapped key system access gate. The radial conveyor can be operated from a control panel at the reception hopper, via remote control by the shovel operator or from the batch cabin. The radial conveyor chassis and stringers are finished in Tarmac livery white. The handrails are finished in high quality powder coated yellow, the threads are galvanised and the conveyor guards are finished in high quality powder coated red which is Tarmac spec. plant indication coding and provides excellent corrosion protection. The radial conveyor feeds into the aggregate bins.
The aggregate bins unit consists of 5 x 40 tonne aggregate bins with twin clam shell door outlets, vibrating motors and moisture on the fines bins. The weigh conveyor is a twin rail chassis design conveyor with a flat belt driven by a Nord geared motor unit providing the best in both efficiency and reliability. The weigh conveyor is equipped with vibrating motors and a manually adjustable outlet feed door. The weigh conveyor chassis and boot hopper is finished in Tarmac livery white. The weigh conveyor guards are finished in high quality powder coated red which is Tarmac spec. plant indication coding and provides excellent corrosion protection.
The aggregate bins unit is enclosed with box profile cladding and finished in Tarmac livery white. There is one double door access point in the lower weigh-belt section of the unit giving excellent access and egress to the unit for cleaning and maintenance.
The weigh conveyor feeds into a Teka single speed double drive tilting skip system. The skip system was installed in order to keep the plant footprint to a minimum. It takes the material from the weigh conveyor almost vertically to the mixer rather than an inclined conveyor which takes the material outwards and upwards. The Skip system can also load the mixer quickly and can be used as a holding hopper during the mix cycle potently speeding up the batch cycle time. The skip system is totally enclosed within the building and protected by proximity guarding with a fortress trapped key system on every level.
The batch tower is completely enclosed in box profile cladding which is finished in Tarmac livery white.
The skip system feeds into a Teka TPZ 3000 Planetary mixer. The mixer is equipped with dual discharge doors, dual access doors with fortress trapped key system, a mixer washout system with four 360° high pressure heads. Suspended above the mixer are the cement weigh hopper, the water weigh hopper and plant internal water tank. The plant pumps and washout system panel are also located on the mixer deck which is spacious with good access to all the equipment.
A set of steps leads to the top floor of the batch tower which is the same size as the lower deck with the heads of the screw conveyors, admixture system, dust control system, plant compressor and gantry rail on this floor it is ideal for storage of fibres and spares. The overhead gantry rail can be used to lift fibres and spares from ground level through the canter-lever doors on the front of the tower and onto the top floor for storage.
Behind the batch tower is a spacious eight by three meter batch cabin/office with separate switch room and windows facing the discharge chutes. The cabin is on its own stand with access steps and has a full length front platform for loading fibres. The stand, steps and walkways are galvanised and the handrails are finished in high quality powder coated yellow.
To complete the installation a 20,000 litre fresh water storage tank with access ladder and pumping system were also designed, manufactured and installed by TBS. The existing split silo was rotated, rewired and two new screw conveyors were installed from it to the new cement weigh hopper. A second single outlet silo was installed and a new screw conveyor was installed from it to the new cement weigh hopper. A 30,000 recycled water system was installed. A modern canteen, toilet, dry room and office container unit was installed. The existing 6 line admixture pumps and add mixture tanks were installed and finally the plant generator and a site storage container were installed.