Mining
for more
BEML delves into the intricacies of hydraulic systems used in the mining
industry especially those utilised in mining equipment
CSince
its inception three decades ago, Bharat Earth Movers (BEML) has supported
the Indian mining industry in its endeavour to win over the earth, by
supplying mining and earthmoving equipment, where the mobile oil hydraulics
plays a vital role in successful operation. The equipment that is manufactured
and supplied to the mining industry can be broadly classified into the
following categories:
1. Hydraulic excavator
2. Bulldozers
3. Dumpers
4. Wheel loaders
5. Motor graders
6. Underground mining equipment like side discharge loaders.
Brief details of equipment and the salient features of hydraulic system
engineered on the same are detailed below:
Hydraulic excavator
The advent of hydraulic excavators has created a sensation in the mining
sector in the view of their higher productivity; lower operating cost
and a very high level of reliabilities in operation. All the operations
of this equipment such as, travel, swing and work attachment are effected
by sophisticated high pressure hydraulic system, due to which the equipment
itself is called as ‘hydraulic excavator’. Hydraulic excavators
are basically loading machines, which can excavate the soil and load
or they load from the heap.
The salient features of hydraulic system used in these excavators are
described below. Three or two stage Open centre Load Sensing hydraulic
System (OLSS) engineered on these equipment results in the effective
use of engine horsepower and thereby minimising the losses in the hydraulic
system. The energy saved by reducing the losses in this vital system
is as high as 20 per cent when compared to other excavator systems.
The maximum utilisation of engine power is achieved by the Torque Constant
Control (TCC) arrangement. In this arrangement the total torque imposed
on the engine simultaneously by all pumps is controlled to be constant.
A high efficiency of the hydraulic system is achieved by minimising
the losses associated with conventional systems, such as the fine control
loss, the neutral loss and relief loss. Optimised hydraulics minimise
the loss of hydraulic power resulting in energy saving. In addition,
an advanced control mode system can balance available engine power with
hydraulic output for maximum performance and optimal fuel consumption.
Bulldozers
Bulldozers are the backbone of any mine, which are used for crating
heaps after blasting the soil or for levelling operations. BEML manufacturers
wide variety of bulldozers with flywheel horsepower 66HP, 90HP, 165HP,
180HP, 230HP, 410HP and 770HP. Hydraulic system plays a vital role in
these giant equipment, particularly in the systems like the converter,
the power shift transmission, steering, braking, work attachment and
ripper attachment. The hydraulic system used in a bulldozer is comparatively
simple in nature when compared to the complexity of excavator hydraulics.
Pumps used in this system are of external gear type, which are preferred
for it’s low cost and ruggedness. Two separate modules of a tandem
pump are used to power the blade circuit and ripper circuit individually.
....CONTD
