Earlier this month, Rotec Hydraulics completed a large project for a new customer who specialises in all aspects of confined space working from sewer rehabilitation, timber headings, tunnelling, grouting, all types of shaft sinking and associated clean and waste water works.

With a wealth of experience constructing shafts up to 30 metres in diameter and to depths of 35 metres, the specialist construction company sink shafts using various techniques – including hydraulically jacking segmental shafts vertically.

Rotec were asked to design, build and deliver ten hydraulic cylinders and two hydraulic power units (HPUs) capable of powering 40 tonne hydraulic jacks with up to 210 bar pressure for a significant shaft sinking project.

The HPUs operate ten hydraulic jacking cylinders using ten off detented levels and a single sprung loaded dead man’s lever. The jacking cylinders have a 160 bore, 110 rod, 1200 stroke and are mounted in frames which push down concrete segments to line holes. Each cylinder can provide up to 40 tonne force with 210 bar pressure which can be controlled by an adjustable knob on the HPU.

To speed up the extension and retraction of the cylinders, the HPUs have been designed with a two-stage pump which produces a faster flow when less hydraulic pressure is required. The pump is powered by a 7.5 kW 3-phase electric motor which is controlled by electrics mounted in an enclosure on each HPU. This allows the pump to be started and stopped easily, as well as providing essential emergency stop buttons.

Both HPUs have a 500 litre tank with pressure and return filters, in addition to a fitted level/temperature gauge. Connections from the HPUs to the cylinders are via protected hoses with quick release connectors.

To increase safety and reduce risk of harm to the operator, the hydraulic hoses on both the HPU and those to the hydraulic cylinders have been fitted with hose burst protection and whip checks where necessary.