Gear Units from 500 - 15.000 kW

Selection Diagram for Dredge Pump Gearboxes

design criteria: Ka = 2,25; Sh = 1,4; Sf = 1,8

Selection Diagram for Dredge Pump Gearboxes

DESCRIPTION GENERAL
Gearboxes of the new GTD-Series have been developed for wet dredging applications such as dredge pumps installed in the engine room or on a cutter ladder with different working angles.These gearboxes with helical gearing are in one- or two-speed design, with one inputand one output shaft. In case of two speed gearboxes the two change gears are arranged on the output shaft. The speed change is executed via pneumatic cylinder.

NAMING CODE: EXAMPLE   -   DA1RH 900 - STC

Options:

• Different design / offset on request
• Turning drive also usable for easily gear change
• Highly flexible / air clutch coupling combination
• Mechanical overload protection
• Electronic overload protection for gearbox with built- in clutch
• Supervision instruments acc. classification rules

HOUSING
The housing which consists of a bottom, middle rsp. a top section is in welding construction. The torsionally-stiff design warrants a safe torque and transmission of the forces to the ship’s foundation.

GEAR WHEELS
All stages have single helical gear teeth which are of case-hardened and ground design. The connection between the gearwheels (stage 1 and 2) and shaft is effected by means of a fitting key.

SHAFTS
The input and output-shafts have been designed with cylindrical shaft journals with fitting key for accommodation of the highly flexible / air clutch coupling combination.
The output shaft of the gearbox is hollow bored for the oil supply of the free running gearwheel stage.
The surfaces of external flanges, ends of shafts and flange attachment face are preserved with an anti-rust coating.

BEARINGS
The gearbox shafts are borne in roller bearings, rsp. plain bearings.
The shift gears on the output shaft are running in bronce slide bearings.

GEARBOX OPERATION
The gearbox is placed in the engine room. Gearboxes supplied by GTD are not filled with oil.
The casing of the dredge pump is standing separately.

GEARBOX TYPE: … (standard design)
Drive effects by a diesel motor via a highly flexible / air clutch coupling combination.
Air feed effects by hollow bore in the input shaft.

GEARBOX TYPE: A … (with integrated thrust bearing)
The impeller of the pump is fitted directly to the gearbox output shaft by a thread. The radial and axial forces, coming from the dredge pump, are absorbed by the bearings of the gearbox output shaft. The pump casing is flanged to the gearbox.

GEARBOX TYPE: C … (input shaft with multi plate clutch)
The built-in multi-plate clutch having steel/sintered metal friction elements is actuated by means of oil pressure and is engaged via a two-stage control valve. The clutch will be engaged and disengaged by means of an electrically operated
3/2-way valve with emergency hand actuating system.

TURNING DRIVE
Electrically driven frequency controlled multistage turning gearbox for changing of gears as well as for assembling respectively disassembling the impeller of the dredge pump. At engaged turning drive the speed at the output shaft is approx 1.5rpm for turning the impeller and 0.5 rpm for gear changing. Engaging and disengaging of the turning drive is done by hand rsp. of a pneumatic cylinder. It is only allowed to switch on the pneumatic cylinder at standstill of turning gearbox and dredge pump gearbox.

LUBRICATION AND COOLING
All of the components required for the lubrication and cooling are mounted on the top of the gearbox and permanently interconnected by pipe work. The oil is supplied by a build on lube oil pump. Gears and bearings are lubricated by oil circulation. The gearbox casing serves as an oil reservoir. The min. / height of oil level in the gearbox are controlled by a level control device. The oil is cooled by a water-oil cooler for fresh water.

MONITORING
Visual and electrical control devices for pressure, temperature and oil level are installed in lubrication circuit. All electrical devices are cabled into a terminal box.
Furthermore information:
- signal list / alarm points: acc. hydraulic scheme resp. table of contents
- gear switching acc. pneumatic scheme

PAINTING AND PRESERVATION
The gear unit is painted internal and externally with a finished paint coat acc. GTD-Standard (by request externally acc. customer specification). The internal preservation of the unit is done using with GTD-test run oil, which provides adequate corrosion protection for a period of 12 months, if the equipment is stored in a dry room.

FUNCTIONING
The gearbox has to transfer the power between the diesel engine and the dredge pump. The speed of the engine will be reduced to the speed of the dredge pump according to the engaged gear.