Notes About Rope Haulage
Notes Of Rope Haulage
Types of Rope Haulage
1)Direct
rope haulage
a) Single
drum direct rope haulage
b) Double
drum direct rope haulage
2)Main &
tail rope haulage
3)Endless
rope haulage
a) Under
rope endless rope haulage
b) Over
rope endless rope haulage
4)Gravity
rope haulage
1)Direct
Rope Haulage
a)
Single Drums Direct Rope Haulage: This is simplest system of rope
haulage. It consists of one track, one rope & one drum which are connected
to a motor through gears. One end of the rope is connected with the train of
tubs on the track & another end of the rope is connected to the drum. When
the drum rotates situated at the top of the incline, the loaded tubs moves
upwards. But for the downward journey of the empty tubs it does not require any
power because a tub moves downward due to their own weight. The system can be
on inclines steeper than 1 in 12 & the speed of the haulage is 8 – 12 kmph.
Advantages
of Single Drum Direct Rope Haulage
1)Simple in
operation.
2)Only one
brake is required.
3)Extension
is easy.
4)Branched
roads can also be served, if gradient is suitable.
5)Can be
used in narrow roads.
Disadvantages
of Single Drum Direct Rope Haulage
1)High
power demands for upper journey of loaded tubs.
2)Efficient
breaking system required for downward journey.
3)High
speed haulage demands more maintenance of track.
4)Cannot be
used for less incline roadways.
5)A
derailment is associated with heavy damages.
6)Due to
high speed more dust, more wear & tear.
b)
Double Drum Direct Rope Haulage: It consists of two drums, two
ropes & two tracks but only one driving motor. One end of each rope is
connected with two drums & another end of rope is connected with the set of
tubs. In such a way that when one set of tub is at incline top, the other set
is at incline bottom. The two drums are connected with each other. When drum
rotates, the rope coils on one drum & uncoils from another drum. It can be
used if inclination is more than 1 in 12. The speed of the system is 8 to 12
kmph.
Advantages
of Double Drum Direct Rope Haulage
1)Higher
output.
2)Less
power demand.
3)Branched
roads can also be served, if gradient is suitable.
Disadvantages
of Double Drum Direct Rope Haulage
1)Wider
roads required.
2)Efficient
breaking system required for downward journey.
3)High
speed haulage demands more maintenance of track.
4)Cannot be
used for less incline roadways.
5)A
derailment is associated with heavy damages.
6)Due to
high speed more dust, more wear & tear.
2)Main
& Tail Rope Haulage: In this system the haulage engine
provided with two separate drums, one for main rope which hauls the loaded tubs
up the gradient & one for tail rope which hauls the empty tubs down the
gradient. When one drum is in gear, the other drum revolves freely but
controlled. The main rope is approximately equal to the length of the incline
& tail rope is twice this length. The system can be used if the gradient is
unsuitable for the use of direct rope haulage. Its speed is 15 – 18 kmph.
Advantages
of Main & Tail Rope Haulage
1)Can be
used on less inclined & undulating roadways.
2)Branch
roadways can be served.
3)Only one
track is required.
4)Less
number of tubs is required.
Disadvantages
of Main & Tail Rope Haulage
1)Due to
high speed more dust, more wear & tear, more maintenance.
2)Derailment
causes high damage due to high speed.
3)More
power is required than the endless rope haulage.
3)Endless
Rope Haulage: This system consists of double track, one driving
pulley & one return pulley. An endless rope passes from the driving pulley
which is situated at the inby end & back again to the driving pulley. One
track is used for loaded tubs & another track is used for empty tubs. Rope
moves in one direction only with the speed of 3-7 kmph. Only one train of tubs
is attached to the rope at a time but sometimes a set of tubs can be attached
to the rope. The system is used where the gradient is less, generally less than
1:12 or where the ground is undulating. A squirrel cage motor is commonly
employed.
a)
Under Rope Endless Rope Haulage: If the rope passes below the
tubs, it is known as under rope endless rope haulage. In this system there is
more wear & tear to this rope but also there is an advantage that there is
more direct pull on the tubs.
b)
Over Rope Endless Rope Haulage: If the rope passes over the tubs,
it is known as over rope endless rope haulage. In this system rope is
unaffected by wet floor & liable to wear & tear. The rope is at better
working height & a system is generally used for undulating roadways.
Advantages
of Endless Haulage
1)Because
of slow speed, less wear & tear to the tub wheel & track.
2)Less
maintenance is required.
3)Accidents
do not cause much damage.
4)Less
motor power required.
5)Continuous
flow of mineral or coal is attained.
Disadvantages
of Endless Haulage
1)It
requires wider roads.
2)Not
suitable for Steeper gradient.
3)Load on
the rope is large hence a rope of large cross section requires.
4)Large
number of tubs & clips are required.
5)It cannot
serve a branch road.
6)Extension
is not simple.
7)Minor
injuries to hands & feet are common.
Driving
Pulley or Surge Wheel
Types
of Driving Pulley & Surge Wheel
1)Clifton pulley.
2)V-grooved
pulley.
3)Fouler’s
pulley.
1)Clifton Pulley: This
pulley has tapered throat lining of renewable cast iron or soft steel segment
having a taper of about 1 in 8. These segments are bolting to the rim to
protect the main pulley from wear. The rope is coiled several times (3 ½ - 4 ½)
around the pulley & it enters the pulley at larger diameter & leave the
pulley at smaller diameter. This pulley is commonly used in mines in endless
haulages.
2)V-Grooved
Pulley: This pulley consists of two segments made of renewable
cast iron or soft steel. These segments are bolted to the main pulley in ‘V’
shape. The rope takes only a half turned around the pulley & takes the
necessary grip by becoming wedged between the two inclined segments. The grip
on the rope is directly proportional to the tension in the rope.
3)Fouler’s
Pulley: It consist of number of bell shaped pivoted segments made
of renewable cast iron or soft steel. These segments are pivoted to the main
pulley as shown in figure, the pressure of the rope on bottom of the segment
towards each other so that they grip the rope in proportion to its tension.
Types
of Clips
1)Screw
clip.
2)Small-man
clip.
3)Cam clip.
4)Goose
neck clip.
5)Lashing
chain.
1)Screw
Clip: It consists of two jaws i.e. lower jaw & upper jaw. When
the distance between two jaws is enough to accommodate the rope, the moving
rope is placed in between the jaws & the handle operated which reduces the
distance between the two jaws. Hence the two jaw grips the load rope, due to
this grip as well as tub starts moving with the rope because the clip is
connected to the tub & through a rod or lever.
2)Small-Man
Clip: It consists of two side plates loosely held together by a
bolt which has a spring which keeps the two plates apart. A hand lever pivoted
at ‘P’ & carries a wedge at its upper end. When the hand lever is
depressed, the wedge enters between the two plates to grip the rope. The clip
can be detached automatically from the rope by fixing a trite bar to the
sleeper which raises the hand lever to release the rope.
3)Cam Clip: It
consist of a plate having its one edge bent over to form a groove into which
the rope is pressed a gripped by a lever which is pivoted & other end of
the lever is connected to the tub to a chain. The pull on the chain turns the
lever to grip the rope. The grip on the rope is proportional to the load.
4)Goose
Neck Clip: It consist of an ‘S’ shaped hook loosely into the
holders mounted on the end of the tub as shown. When the rope is placed in
position in the hook at either end or at both end of the tub, the hook turns
through about 300 & grips the rope. The grip on the rope is proportional to
the tension in the rope. But this grip bends the rope which reduces the rope’s
life.
5)Lashing
Chain: It consists of a chain 2.5 to 3.0-meter-long with a hook at
each end. One hook is attached to the tub & other end of the chain is
coiled 3 to 4 times around the rope & the hook is linked to the chain. On
undulating roads chain should be used at both the ends. Generally, in this case
a set of tubs is attached with the rope at a time.
Tensioning
Arrangement for Endless Rope Haulage
For the
proper working of endless rope haulage, a uniform tension should be maintained
in the endless rope. The common practice to ensure proper rope tension is to
pan the rope half turned around the pulley mounted on the tension which is
placed on the rope. Heavy weights are attached to the boggy through chain &
wire rope. This way the weight always acts downwards. Hence a uniform tension
in the rope is always maintained.
The correct
place for the tension boggy if the slope is most likely to occur. Generally,
the tension boggy is kept at the bottom end of the haulage.
4)Gravity
Rope Haulage: This is haulage without motor or any external source
of power. It is used when load is to be transported from uphill to down the
gradient. It consists of brake path on one side & is way pulley. It is
located at the top of the incline roadway. The one end of the single rope is
attached to the loaded tub & the other end is attached to the empty tubs
while passing over the jib pulley. When the loaded tubs move down the gradient
at sometimes empty tubs moves up the gradient. The brake strap is provided with
brake path & is connected to a lever. When the lever is depressed the
braking effect on the jib pulley is produced.
Essential
Requirements of a Haulage Track
1)Rail
should be of an adequate weight & cross section.
2)Sleepers
used should be of single track construction.
3)Rail
should be jointed by fish plates, bolts & to the sleepers by log spikes.
4)Track
should be well.
5)Change in
gradient should be made by vertical curves.
6)Curve
should be of large radius.
7)At curves
the other rail is super elevated.
8)Cross
gradient should be there for good system of drainage.
9)There
should be careful alignment before & after ballasted.
Safety
Devices
1)Backstay
or Drag: These are used behind an ascending set of tubs as a safe
guard against a broken rope or coupling. It is very strong & made up of
steel of rail section. If the tub coupling or rope breaks, the ascending tub
starts moving backward. At the pointed end of the drag gets fixed in the ground
or sleeper to derail the tubs. It is used in direct rope haulage.
2)Back
Catch or Monkey Catch: It comprises a piece of wood or rail placed
in such a way that one end is always high enough to catch the axle of the
backward run away tub. When the tubs move in moving in correct direction, its
axle presses the elevated end of the back catch so that it can cross the back
catch. In this safety device movement of tubs is possible because only in one
direction. It is used in endless rope haulage.
3)Spring
Catch: It consists of a wooden block at one end & pressed
sideways over the rail at the other end by a spring as shown in figure. The tub
moving in proper direction pushes aside the wooden block & passes over it,
but due to spring the wooden block at once returns to its original position to
arrest a backward run away tub. It is used in endless rope haulage.
4)Age
Croft Device: It is somewhat similar to a monkey catch. But their
designs to arrest forward run away automatically. When the tub is moving in the
direction from B to A as shown in figure the front axle of the tub depresses
the higher end ‘A’ of the pivoted bar AB & so raises the forked end ‘B’ to
axle height. If the tub is moving at normal speed the ‘B’ end drops before the
back axle reaches it. If the tub is moving very fast, the back axle of the tub
is caught by the end ‘B’ & the tub is held in position. It is used in
endless rope haulage.
5)Jazz
Rails: In this safety device, the straight rail track is giving a
very slight curve & again made straight. In some cases, the track is bent
at both sides & then made straight. At normal speed the tubs can easily
cross it in either direction. But the uncontrolled tubs get a high speed hence
they cannot cross the jazz rails. Hence the derailment takes place. It is used
in all types of haulage.
6)Stop
Block: They are made in difficult forms & are used to stop or
derail a moving tub on a track. Generally, a wooden block which is pivoted to
the sleeper at one end is kept across the track to derail the unwanted tubs.
The track can be cleared by positioning the wooden block inclined with the
track. It is used in direct rope haulage & main & tail rope haulage.
7)Run
Away Switch: This switch is normally kept open by a spring. When a
lever handle is operated by an operator, the switch gets closed. And tubs can
pass over it otherwise the tub derails when they pass over the runaway switch.
It is used with direct rope haulage & main & tail rope haulage.
8)Runaway
Switch & Stop Block: This safety device is situated at the
incline mouth of direct or main & tail rope haulage. In this safety device
the stop block & the run-away switch is so interconnected that at any time
one of them is working. The distance between stop block & run away switch
should be more than the train length (train length + 4.5 meter). The stop block
& the primary switch is connected by a lever. When the lever is operated to
clear the track from the stop block the run-away switch is open. But as soon as
the tubs crosses stop block the lever is again operated to close the run-away
switch & at the same time it is on the stop block.
9)Drop
Warrick: This safety device consists of a strong girder which is
pivoted at the roof level through an eye bolt & pin. The pin is operated
through a long wire attached to the swinging lever which is to be operated by
the tubs, on the uphill side when the tubs are moving in downward direction.
The control movement of tub does no exert in a pull or the wire but in case the
tub running uncontrolled. It extracts a high pull on the wire through the lever
which is turned. Drop the pivoted girder between tracks to arrest the forward
runaway of the tubs. It is used with direct rope haulage, main & tail rope
haulage & endless rope haulage.
10)Manholes: Height
should be more than 1.8 meter; depth should be more than 1.2 meter & width
should be more than 0.7 to 1 meter. When person is allowed to work or pass
through an incline, when the haulage is in motion, the manholes are made along
the roadways sot that person travelling can take shelter in the manholes. The
interval between two manholes should not be more 10 meters, but if the gradient
is less than 1:6 the interval may be up to 20 meter. If the roadways are less
than 1.8 meter in height the manhole should be made up of full height of the
roadway it is used in direct, main & tail & endless rope haulages.
LOCOMOTIVES
Types
of Locomotive Haulages are
1)Diesel
locomotive
2)Electric
locomotive/overhead wire locomotive/trolley wire locomotive
3)Electric
battery locomotive
4)Compressed
air locomotive
Main
Parts of Locomotives
1)Chassis: chassis
is rigid frame work of steel section.
2)Driving
wheels, axles, springs & brake blocks etc. mounted below the Chassis.
3)A
power Unit: it may be a diesel engine, an electric motor, a
battery or compressed air.
4)Operator’s
Cabin: Having control panel with brakes, operating system, horn
etc.
5)Lights at
both ends.
6)A screw
brake for emergency.
7)For large
size locomotives an air compression for power brakes.
Limitations/Applicability
of Locomotives
1)Generally
the gradient should be less than 1:100 but it can be used up to a gradient of
1:25.
2)Where
track is in settled ground.
3)Where
roads/galleries are reasonably wide & high.
4)Where
transport distance is large.
5)Where
production is high.
6)In the
intake airways where the air velocity is high enough to keep the fire damp
percentage below the danger limit.
Locomotive
Haulage: In case of rope haulage the power to
move the load is available from external fixed motor to the haulage. While in
case of locomotive haulage the driving unit i.e. locomotive is coupled to a
train due to which more safety can be attained. The locomotives are very
flexible in nature & they can be used for men transport also.
1)Diesel
Locomotive: Diesel locomotive are commonly used in number of
mines. Their weight varies from 3 tonnes to 15 tonne & power from 50kw to
75kw. The power unit is a diesel engine. The locomotives used in underground
coalmines have a power unit in a flame proof enclosure as a safe guard against
ignition of fire damp. In coal mines the diesel locomotives are not allowed
where the percentage of inflammable gases is more than 1.25% in the general
body of air. Hence these are generally used in intake roadways. The exhaust of
the diesel engine includes oxygen, nitrogen, carbon dioxide & small
quantities of oxides of sulphur & nitrogen & other aldehydes which
smell badly & causes irritation of the nose, throat & eyes. To remove
these oxides & aldehydes the locomotives are fitted with exhaust
conditioner.
Exhaust
Conditioner & Flame Trap: The exhaust gases from the engine strikes on the surface of the
water in the chamber A. This traps hot particles & washes out the sulphur
oxides & aldehydes. The gases then rise through a flame proof slag wool
which is kept moist by water & thereafter pass through second chamber.
Similar chamber B, where gases are further cooled & filtered before passing
through the flame trap. A flame arrester consists of a removable stainless
steel plates 1/2mm apart. Finally, gases are mixed with about 30 to 40 times
their volume of fresh air before entering in the atmosphere. In chamber A, a
water level indicator is installed in such a way that if water level falls
below certain level, the brakes are applied automatically. The exhaust conditioner
should be replaced by a clean set after every 24 hours.
Advantages
of Diesel Locomotives
1)Cheaper
2)Completely
self-controlled
Disadvantages
of Diesel Locomotives
1)Danger of
fire in handling the diesel.
2)production
of poisonous gasses
3)Adds
heats to the atmosphere.
4)More
maintenance required.
5)More
employees required.
2)Electric
Locomotives: The electric locomotive is equipped with an electric
motor which draws the current from the overhead wires through a pantograph or
through a long pole which is kept pressed against the overhead conductor by
spring tension. The DC supply to overhead wires is 250 volts. These locomotives
may be used in degree I gassy mines. The overhead wires are suspended through
insulators over the track at a height more than 2 meter.
Advantages
of Electric Locomotives
1)More
reliable
2)Light
weight
3)Less
maintenance
4)Good
control
5)Small
size
6)No
exhaust gases
Disadvantages
of Electric Locomotives
1)High
initial investment
2)Danger of
shock & fire
3)Derailment
is major problem
3)Electric
Battery Locomotives: The power unit of an electric battery
locomotive is a DC electric motor which receives current from a storage battery
carried in the locomotive itself. Such locomotives are for light & medium
duties. The batteries are of lead acid type & each battery consists of a
number of 2 volts’ cells & their no varies from 40 to 70. The capacity of
the battery to work is 8 hours & its charging time is also 8 hours.
Advantages
of Battery Locomotives
1)Less
maintenance.
2)No
poisonous gases.
3)No
overheads wire’s problem.
4)Quite in
operation.
Disadvantages
of Battery Locomotives
1)Hydrogen
gas is liberated.
2)Flame
proofing is not possible.
3)Overheating
of cell may cause sparking or fire.
4)Large
cross section.
5)Expensive
batteries & less life.
6)Special
charging stations involve more reliable.
4)Compressed
Air Locomotive: There are no compressed air locomotives in Indian
coal mines. The source of power used in air locomotive is compressed air
cylinder, installed over the locomotive. This cylinder supplies the required
quantity of compressed air to the locomotive. These locomotives are very safe,
reliable & very useful in hot & dip mines. Even though their working
cost is very low, they are not used in Indian coal mines due to their high cost
of installation. These locomotives are used for light duty work only.
Advantages
of Compressed Air Locomotives
1)Very
safe.
2)Very
reliable.
3)Less
maintenance required.
4)Cooling
effect on air.
Disadvantages
of Compressed Air Locomotives
1)High
initial cost
2)Danger of
pipe leakage.
3)Efficiency
is less.
Super
Elevation/Cant: On a curve, centrifugal action
creates a tendency for the train to leave the track & proceed along a line
tangential to the curve. This makes the wheel flanges very hard against the
inner edge of the outer rail, causing more wear on wheels & rails. To
counter act this; the outer rail should be raised above the inner one. This
level difference between the inner rail & outer rail is known as super
elevation.
S.E. = AV2/g.r
meter.
Where,
A = gauge
width in meter.
V =
velocity in meter/sec.
g =
acceleration due to gravity (9.8 meter/sec)
r = radius
of curve in meter.
Ideal
Gradient: If the Tractive force required to
haul the loaded trail down the gradient is same as it is required to haul the
empty train of the gradient with the same velocity, this gradient is known as
ideal gradient.
Let,
WL = Weight
of loaded train.
WE = Weight
of empty train
1 in n =
Ideal gradient
m =
coefficient of friction
Case
I: When loaded train is moving downward
GL =
WL.g.1/n
FL = WL.
g.(
TF = FL –
GL
TF = WL. g.
(- WL. g 1/n-------------------------- (I)
Case
II: When empty train is moving upward
GE = WE.g.1/n
FE = WE. g
TF = FE+GL
TF = WE. g
(+ WE.g.1/n--------------------------(II)
As per the
definition equation (I) = (II)
WL.g.
(-WL.g.1/n = WE g + WE g 1/n
WL -WE =
WE.1/n + WL.1/n
((WL-WE) =
1/n (WE+WL)
n= (WL+WE)/
((WL-WE)
Drawbar
Pull: This is that part of the Tractive
force which remains available for pulling corrected load, hence drawbar pull
can be calculated after deducting from the total Tractive force, the Tractive
force required to haul the locomotive itself.
TF=TM Wloco =
kg
TF= TM Wloco.
g = N
TM=
Coefficient of adhesion
Force =
mass X acceleration
(TF+GL-FL=mass
X acceleration.
Post a Comment