Day 10 - Thursday 17 May - A detailed look at the drainpipe layer

A view of the complete pipe laying vehicle.

The complete pipe laying vehicle viewed from the rear.

This position of the vehicle is controlled by a laser guidance system.

The cable drum mounted at the front of the vehicle.

The pipe comes off the feeder into a tube mounted on top of the tractor cab.

Behind the cab the pipe turns 90 degree downwards.

The pipe feeds down and into the trench dug by the rotating "blade".

The rotating blade. The teeth are individually mounted so that they can be renewed.

The earth dug from the trench is lifted by an elevator into an awaiting dumper truck.

The hopper at the back of the vehicle filled with gravel to infill the trench after the pipe has been laid.

Gravel fed from the hopper into the trench.

More sand has arrived - part of the 2,000 tons that will eventually be distributed on the surface.

Work continues throughout the day to lay the first 11 lateral drains at 10m intervals.   Tomorrow work will start to lay another 11 lateral drains mid-way between those laid today.

So we take a detailed look at the special purpose piece of equipment, designed and built in the Mabbott workshops, to dig and lay 100mm diameter drains.

The device has a coil of pipe on the front of a tractor.   The pipe is fed through a tube over the cab of the tractor,    A large circular grinding wheel (like a heavy-duty circular saw) digs out the trench.   The soil that’s been dug out is fed via an elevator into a waiting tractor-drawn trailer or dumper truck.    The drainage pipe is fed from the top of the tractor into the trench.    At the back of the device is a hopper filled with gravel which dispenses gravel into the trench covering the drainage pipe.   From tine to time the hopper is re-filled with gravel.    The three tractors move forward at a slow walking pace.  Perfect synchronism of the three tractors is essential.   The minimum team to carry out this operation is three.  However, additional tractors and trailers removing the soil and filling the hopper speeds up the operation significantly.