Dust Free Surface Preparation in the Shipbuilding and Repair Industries

A ship cleaning system with a difference set new standards in environment-friendliness at the "SMM92" marine technology show in Hamburg.

Paul Hammelmann Maschinenfabrik was awarded a prize for "efficient eco-concepts" by the Federal German Minister of the Environment, Professor Dr. Klaus Topfer. The cleaner has already proved itself in practice, one of its assignments being to remove limpets, old paint and rust from the hull of the luxury liner "QUEEN ELIZABETH".

The HAMMELMANN DOCKMASTER is a semi-automatic ship hull cleaning, derusting and paint stripping unit capable of operating at a maximum pressure of 2500 bar (35,000psi) without the need for any additives. Only the material removed needs to be disposed of, i.e. marine growth, rust, paint etc.

The system has advantages over conventional sand and grit blasting in that it is completely dustfree. A built-in system filters the water and collects the removed solids enabling disposal in a controlled manner.

The pre-cleaned water can be fed together with other waste and rainwater to the dock water treatment plant.

Compared with known dry blasting methods the amount of waste to be collected is greatly reduced. The use of cost intensive shrouding against dust is not necessary and the waste water van be fed to a water treatment plant together with any rainwater etc.

At an operating pressure of 850 bar (12,300 psi) a surface quality of between SA 1-2 can be achieved. Surfaces prepared by HAMMELMANN systems meet the standards set by international paint manufacturers for the application of surface tolerant primers. Advantages of the DOCKMASTER System

When using compressed air driven blasting units with sand, copper slag or grit a large amount of contaminated blast material is generated. When using the HAMMELMANN DOCKMASTER water jetting system approximately 98 percent of the waste material is eliminated.

As an example, when blasting about 4000m 2 (43,000 sq ft) of hull up to 250 tons of contaminated copper slag results. When using the high pressure water jetting method the waste material is reduced to 5 tons of paint, rust and marine growth.

For this reason the DOCKMASTER SYSTEM was awarded the German environmental prize "Ecological concepts in business" 1991.

Design characteristics of the DOCKMASTER SYSTEM Chassis:

The torsion free chassis with solid rubber tyres is designed for maximum stability. It allows operation of the unit with the jib fully extended. Front and rear axles can be steered independently giving maximum manoeuverability in narrow docks or access ways to the dock. The unit is driven via the rear axles with built-in differential lock.

Front and rear ends of the chassis are fitted with anti-collision sensors which will stop the unit immediately any contact is made. with obstacles on the dock floor.
Telescopic Jib:

The telescopic jib has been designed to withstand the tough conditions in repair docks. The jib with its counter weight is mounted on a turntable supported by roller bearings. The jib can be slewed +300 /- 100. The telescopic jib has a maximum working height of 23m (75.5ft). The two telescopic segments are operated by a combination of hydraulic cylinder and chain drive, retracting or extending simultaneously. The segments are precisely guided and supported by over dimensioned, high strength plastic slide plates.

Maximum luffing height is controlled and limited electronically. Hydraulic System:

Two independent hydraulic circuits each with one hydraulic pump are installed. The system is controlled by proportional valves, solenoid valves, pressure limiting valves combined with hydraulic motors and hydraulic cylinders.

The hydraulic pumps are driven by an air cooled and sound dampened Deutz Diesel engine at 1800rpm.The hydrostatic drive to the independent rear axles is designed for a maximum speed of 2.4km / h and for a maximum gradient of 9.50.

An electro/hydraulic control device ensures a constant pressure of the jetting tool onto the ship hull whatever the jib luff angle. 
Electrical Installation:

All electric and electronic elements of the DOCKMASTER SYSTEM are installed in a waterproof cabinet. The operating voltage is 24 Volts d/c with the power supplied by a heavy duty generator on the diesel engine.

A digital pressure and working height display is installed underneath counter weight and can be read at a distance.

The DOCKMASTER is operated by radio remote control.

For more information: 
MR BERNARD TAN 
ENSURE EQUIPMENT PTE LTD 
TEL: 273 8844 
FAX: 271 7374