Pre-stressed, Precast Railway Sleepers
"Xindadi" has more than 40 plants in china with complete mould circulation systems for many different production methods for Pre-stressed precast concrete Railway sleepers for more than a decade now.
We have solutions from start-up concepts, with low levels of automation & upgradeable to more & more production per day as per clients requirement.
Xindadi is holding nearly 90% of Chinese market for supply of plant & machinery for Pre-stressed precast concrete Railway sleepers with low vibration on tracks.
Pre-stressed concrete sleepers for track systems are therefore increasingly replacing the steel or timber sleepers in rail networks. They are more durable, require less maintenance and are also environmental friendly. In order to cover the rising demands of the industry and the public authorities & building contractors are increasingly investing in modern production plants.
Manufacturing Process:- The moulds are oiled and cleaned first before the installation of the anchors for the fastening of the rails later on. Subsequently, the pre-stressing wires are installed in the mould prior to concreting.
Individual wires are connected with anchor plates to make an assembly before the anchor plates are fastened to the tensioning and anchor bolts in the sleeper mould. Subsequently, the wires are pre-stressed by means of the tensioning bolts whilst constantly monitoring and recording the tightening torque of each pre-stressing wire.
The pre-assembled mould is transported onwards by roller conveyors to the sound insulated Concreting chamber. The semi automated concrete distributor fills the moulds precisely via electrically driven discharge screws. A high frequency vibrating station ensures homogeneous concrete Compaction.
The concreted mould is subsequently transported via a corner transfer conveyor and chain conveyors to the hardening chamber. There, an overhead crane takes up the mould by means of a suspended spreader bar and stacks the moulds on a prepared trolley car. The hardening chamber is thermally insulated and equipped with a heating device. The trolley cars move through the hardening chamber on rails according to predefined cycle times. To this end a chain pusher pushes the entire train of cars one car length further at a time. In the exit area a further chain pusher pulls one run-off Carriage at a time out of the hardening chamber following a hardening time of about 20 hours.
A total of two / three transports lines are provided for in the hardening chamber.
As in the overall plant circulation, a central master computer controls all transport and storage process here plus Analyses indicate the output quantities and plant productivity at all times. A further overhead crane in the outlet area of the hardening chamber is equipped with a special lifting spreader bar. “One of the highlights here is the integrated turning device. The spreader bar is equipped both for the transport and for the turning of the mould”. First of all the moulds are taken off the run-off carriage and stacked on a chain conveyor.
The pre-stress release process is subsequently initiated via a semi-automated de-tensioning station. To do this the pre-stress is introduced into the concrete sleeper. Subsequently, the turning spreader bar turns the mould by 180 degrees, before the shake out process is carried out by means of an electric lifting mechanism. After shaking out, the mould is turned back by 180° and fed back to the mould circulation.
The manufactured pre-stressed concrete sleepers are delivered ready for laying. For this the entire reinforcement is installed in the sleeper and pre-stressed according to the standards.
