Largest variable moment vibrator gets to work

Piling equipment specialist Watson and Hillhouse has purchased what it believes is the largest variable moment vibrator in the UK. The unit, a PVE40VM from Dutch manufacturer Dieseko, is being used by Cementation Foundations Skanska for installing temporary casings for rotary bored piles on a hospital project in Romford.
The freely suspended unit weighs up to 8.5t (depending on configuration), can drive casings up to 2m diameter and sheet piles in excess of 20m. "We see casing and pile sizes in the bored market getting bigger and this is one reason we invested in this machine with its 40kg/m eccentric moment," said sales and marketing director Phillip Bell.
Variable moment vibration allows the unit to start and stop while in balance, thereby avoiding any critical frequency area and reducing the impact on the surrounding environment. To achieve this the weight is not moved to the eccentric position until maximum rpm is reached and it automatically returns to the balance position at the end of the cycle before shutting down.
There is also remote control of the eccentric weights and amplitude, allowing the optimum combination to be selected for each soil condition. Power comes from a model 800 power pack with a 573kW Volvo engine.