WATER JET CONFERENCE - Waterjet Technology Association

the battery and placed onto the open oven. This disruption wastes time and the target of
pushing at least 6 ovens per hour falls quickly behind. On the side of the oven where the
coke is deposited into the railway trucks, the door extracting machine is known as the
'Coke Guide' (see figure 7.) The coke guide removes the door, it moves along, positions
the guide at the open oven and when the coke is pushed through, it prevents the red hot
coke from falling onto the bench or walkway around the oven.
On the other side of the oven, the door extracting machine is very different and is
known as a 'pusher' (see figure 1.) It is large enough in size to carry a large ram up to 30
meters long, the ram face being the size of the oven. The pusher removes the door and
then lines up the ram which then pushes all red hot coal through the oven and out of the
other side.
THE ENVIRONMENT
Leaky doors allow coal gas and sulphurous fumes to escape to the surrounding
countryside. When coal gas escapes from a leaky door, usually the gases ignite, causing a
flame on the outside of the oven. These flames allow local overheating of the outside skin
of the door and door jamb and this uneven heating can cause distortion. So, in addition to
the buildup of carbonaceous deposits on the door and the door jamb, a distorted door
presents an even greater problem in making a good seal.
So the benefits of clean doors which are well sealed are many and are listed
below, but not necessarily in order of their importance:
1. The operators have an improved working environment in that there is a reduction of
obnoxious and potentially dangerous fumes.
2. The surrounding countryside is protected from pollution thus keeping EPA satisfied.
3. The doors can be removed and replaced as required and do not hold up the production
of coke.
4. The doors are sealed against the ingress of air into the oven.
5. The oven temperatures can be stablized at the required temperature, therefore less
energy is used.
6. A reduction of distortion due to flaming gases, which would overheat the doors and
frames.
7. A reduction in the burning or wearing of the doors, seals and frames.
TASKS TO BE CARRIED OUT
The only time that is available for cleaning the coke oven doors is during the
pushing cycle. The time allowed here is about 1 minute. Hitherto mechanical means have
been tried by using hand-held scrapers, but with the size of the door and the time
available, only one small part could easily be cleaned by an operator. This is sufficient in
places such as India, where labor is cheap and their ancient coke ovens are only 3 meters
high, but, of course, modern oven doors are up to 7 meters high and are impossible to
hand scrape.
This led to the development of a tracing motion which contained a large number
of spring-loaded scrapers. This tracing motion was positioned up to the door which had
been taken off. Pressure was then applied to the scrapers and the scrapers were propelled
around the door seal with a hydraulic chain drive conveyor. This system allowed buildup
of tar on the scrapers; lumps of tar fell onto the chair drive, jamming up the system,
159