FIELD OF INVENTION
The present invention relates to a lifting device with locking arrangement to lift
mini-stand cover for cleaning gas passage in coke oven plant. More particularly,
the invention relates to a lifting device with safety arrangement of locking the
head of the ministand cover.
BACKGROUND OF THE INVENTION AND PRIOR ART
The charged gas transfer (CGT) car is used in coke oven plant as a pollution
control device to transfer gas from the charging oven (N) to a ready side oven
(N+2). The huge volume of gas is emitted during charging of coal in an empty
oven. The gas is transferred from one oven to other with the help of 'U' tube
fitted in the CGT machine. For this purpose CGT car has to lift the ministand
cover, which cover the ministand pipe. Since the gas mainly consists of hydro-
carbon (tar material), if it is not cleaned in regular basis it may block the
ministand pipe and disturb the gas transfer. Therefore there is a necessity that

ministand pipe is cleaned regularly which otherwise will result in gas emission
which pollutes the environment. For cleaning ministand, its cover is lifted
manually by motorized chain block. The head of cover is first fitted with the
hook fitted in the chain block. If the hook does not hold the ministand cover
properly it may fall on the ground which may injure the person working nearby,
thus making the surroundings unsafe.
In the prior art, the ministand cover is being lifted with the help of a finger type
hook connected with motorized chain block with the CGT machine. During the
cleaning process the cover gets lifted but the hook does not keep the cover
horizontal and there are instances when the cover is either tilted or slipped or
the hook getting bent during operation.
Therefore, there was a need to develop a lifting device having locking
arrangement in order to make the working and the workplace safe and thus
eliminates the disadvantages of prior art.
OBJECT OF THE INVENTION
Therefore, it is an object of the invention to propose a lifting device with locking
arrangement to lift ministand cover for cleaning gas passage in coke oven plant
which is capable of eliminating the disadvantages of prior art.

Another object of the invention is to propose a lifting device with locking
arrangement to lift ministand cover for cleaning gas passage in coke oven plant
which is capable of arresting the slippage of ministand cover during lifting.
A further object of the invention is to propose a lifting device with locking
arrangement to lift ministand cover for cleaning gas passage in coke oven plant
which is able to eliminate the gripping problem by CGT machine during lifting of
cover.
A still further object of the invention is to propose a lifting device with locking
arrangement to lift ministand cover for cleaning gas passage in coke oven plant
which makes the working of the device totally safe.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure 1 shows the difference between prior art and present invention.
Figure 2 shows the finger type hook used in the device of prior art.

Figure 3 shows the lock type hook used in the device according
to the invention.
DETAILED DESCRIPTION OF A PREFERRED
EMBODIMENT OF THE INVENTION
In coke ovens coal is charged to make coke. Coal is kept inside the oven for
around 20 hrs for proper carbonization. During carbonization coke oven gas is
emitted from the coal charged inside the oven. This coke oven gas contains
different types of hydrocarbons which sometimes at high temperature breaks
and gets deposited at the oven roof as roof carbon, or A. P. base, and the portion
through which gas is transferred from one oven to another is better known as
ministand pipe.
In coke oven charging is a process in which coal is charged in an empty oven i.e.
after ready coke is evacuated from the oven by pushing. During charging huge
quantity of gas is emitted and as a pollution control measure the charging gas is
transferred from the charged oven (N) to a ready side oven (N+2), through
ministand pipe via charging gas transfer (CGT) machine.

During charging the CGT machine is centered over the charging oven to connect
with the ministand pipe with the help of U-tube of CGT machine to the
transferred oven ministand pipe to transfer the charging gas from one oven to
another.
Normally the ministand pipe is covered with a ministand cover to keep the oven
sealed. During charging the ministand cover (both N and N+2) is lifted by CGT
machine for transfer the charged gas.
Now if the ministand pipe which transfers the gas is jammed by carbon and tar
deposition, then due to blockage in gas transfer passage the gas could not be
transferred to the N+2 oven resulting in gas emission which pollutes the
environment.
To stop environment pollution it is needed to keep the gas passage clean for
proper transfer of gas. To clean the gas passage manually the ministand cover
is lifted. To lift the ministand cover a motorized chain block attached to the side
of the CGT machine is used.

The head of the ministand cover is first engaged with the hook (1) fitted in the
chain block. If the hook does not hold the ministand cover (M) property it may
fall on the ground which may injure the person working nearby, thus making the
surroundings unsafe.
To make workplace safe, a device (D) for locking the head (3) of the ministand
cover is very much needed and the disadvantages of prior art is eliminated in
this by innovative lifting device having locking arrangement.
The lifting device (D) of the present invention is a fabricated unit. The device
(D) is a lock type hook (1). It consists of a bottom plate (4) made of ½ an inch
thick mild steel material having a milled portion cut (5) in the front of the plate
for allowing the ministand cover head (3) to be disposed in that cut portion (5)
when a semicircular arm (6) hinged in between the bottom (4) and upper plate
(8), rotates around the hinged pin (7) to hold the ministand cover head (3)
circumferentially and being locked by a pin (9) at the hole position (10) when the
pin goes through the hole (10) on the top cover plate (8) and hole (11) of the
arm (6) and a hole at the bottom plate so that the ministand cover head (3) is
firmly gripped by the lifting device (D). The pin (9) is attached to a chain (13).
The top plate (8) is also made of a mild steel plate and attached to the bottom
plate (4) through hing pin (7).

A hook (12) is welded on the top of the top plate (8). The lifting device (D) is
fitted with the chain block through this hook (12). This motorized chain block is
attached to the side of the CGT machine to lift the ministand cover (M).
Disadvantages of finger type hook used in prior art
since the hook is of finger type, cover gets tilted very often.
some time cover slipped out from the hook
very unsafe for the workers.
no locking system as its end is open
ministand cover seating problem after lowering it.
operator's attention is diverted during cleaning job.
Advantages of lock type hook according to the invention
it is a rigid locked type device
cover is completely horizontally lifted with this device.
it is totally safe and ergonomical
there is locking provision in the device for extra safety
there is no chance of slipping of ministand cover during lifting
no gripping problem by CGT machine during cover lifting due to proper
sitting of cover.
operator's attention is not diverted during cleaning job.

WE CLAIM
1. A lifting device (D) with locking arrangement to lift ministand cover (M)
for cleaning gas passage in coke oven plant comprising;
a bottom plate (4) having a milled portion cut for allowing the
ministand cover head (3) to be disposed;
an upper plate (8) attached to the bottom plate (4) by a hinge pin (7);
a hook (12) welded on the top plate for fitment with motorized chain
block of a CG machine;
characterized in that,
the semicircular arm hinged in between the upper (8) and bottom (4)
plate rotates around the hinged pin (7) and holds the ministand cover
head (3) circumferentially and firmly wherein the arm (6) is locked by
a pin (9) at the hole positions (10,11).
2. A lifting device (D) as claimed in claim 1, wherein the said device is a
fabricated unit.

A lifting device (D) with locking arrangement to lift ministand cover (M) for
cleaning gas passage in coke oven plant consists of a bottom plate (4) having a
milled portion cut for allowing the ministand cover head to be disposed and an
upper plate (8) is attached to the said bottom plate by a hinge pin (7). A hook
(12) is welded on the top plate for fitment with motorized chain block of a
charged gas transfer machine. A semicircular arm is hinged in between the
upper (8) and bottom (4) plate and rotates around the hinged pin (7) and holds
the ministand cover head (3) circumferentially and firmly wherein the arm (6) is
locked by a pin (9) at the hole positions (10, 11)