My wife and I where talking tonight about a project she wants to get into. She wants to build an N scale steel mill–more along the lines possibly of a mini mill—and as per usual with a noobie situation she fell over a part of a mill that refers to something neither of us can figure out.
1)–What is a ‘Larry’ car?
2)–How does one go about modelling said ‘Larry’ car?
and as I’m not the best when it comes to explaining these things —where does a ‘Larry’ car go exactly in a mill setting?
She (and myself), would really appreciate it if someone can set her( and myself,again), straight on this.
When I did an Internet search for “Larry car”+“steel mill” I found numerous websites referencing coke ovens. I have never heard of a mini mill with coke ovens, which makes sense since mini mills melt scrap steel and would need to add a small amount of carbon at most. So, it looks like you need not worry about it.
eric is correct. I work at a “Mini-Mill” and there are no coke ovens or larry cars. the carbon and lime is stored in silo’s. (not very exciting) but easy to model. the “mini” comes from the process, not the size of the operation. better buy some gondolas and get good at weathering/beating them up[(-D] good luck
It’s a self-propelled hopper-type car that on rails directly on top of the coke ovens, to deposit coal into each individual oven.
There’s a guy in a suburb of Philadelphia who sells blueprints of just about any type of steel mill-related machinery and architecture. If your interested just PM me and I’ll give you his contact info. Also, there is a Yahoo Group related to steel modeling whose members can probably point you to the places you need to go for that info.
As for me, I just grabbed a bunch of my then-4yr-old son’s lego blocks and “fudged” it [:D] BTW - some people on the above forums [who have worked in steel mills] say that the Walthers HO model doesn’t resemble any known prototype…
Perhaps a better understanding of a coke oven battery will help. One coke oven is a narrow refractory chamber about 18-24" wide up to 12’ high and 50’ or so long. On either side is a narrower refractory chamber where the coke oven gas is burned to heat the coal in the oven without air. this process is called destructive distillation. It causes all the non-carbon gasses and liquids to come out of the coal levaing carbon or “coke”. The gasses are what is burned in the chanbers on either side of an oven. Obviously they are on different cycles so that a constant generation of gasses can be achieved. Coke oven batterires consist of up to 200 of these ovens. On one side is a car with a huge ram and a large plate that “pushs” the oven when finished giving off gas and liquids into a quench car which takes the red hot coke to a station at the end of the battery where it is quenched with water so it just doesn’t burn up when in contact with the air. It then dumps it on a refractory wharf where it is taken by conveyer to a storage area comtrolled by opening doors at various points. On top of the battery is the larry car. the incoming coal is taken by conveyer to a storage silo over the battery. When an oven needs to be charged the larry car is dump filled from the silo and moves across the top of the battery (picture a hopper car with the trucks rotated 90 degrees) to the oven needing charging. There are typically three ports in the top that the car removes the lids, inserts a snorkel and dumps the coal into the recently emptied oven. Topmen will shovel in any coal that misses the mark and reinstall the lids after the larry car goes back for its next load. This is all a coregraphed show with everybody in communication with each other so the ram can remove the door on the pusher side, the quech car driver on the receiver side and the larry car driver to refill the oven once the doors are back on.
Well, on this one, I think I can offer some “inside expertise” if you allow me to draw on the experiences of my father who spent 31 years at the blast furnaces in Wheeling Pittsburgh Steel’s Mingo Junction (Ohio) plant.
There is probably more than one kind of larry car but the one that Dad ran was kind of a self-propelled hopper car as someone else mentioned earlier. But his was right along side of the blast furnace, not at the coke ovens. The larry car ran under the large bins where the raw materials were stored. This being coke, iron ore & limestone. More than one type of iron ore was used based on the proper “mix” for the iron being made.
Raw materials came in on the trestle in railroad hopper cars. No, they didn’t use the small ore hoppers. It was above the bins and the hoppers would be opened to dump the contents of the cars into the bin. Below the bin was a set of tracks where the larry car ran. The larry car operator would position the larry car under the bin & take on a certain amount (by weight) of the raw material. He would then move the car to the skip hole. The skip car ran up a steep incline along side of the blast furnace to put the raw material into the furnace. The contents of the larry car were dumped into the skip car. The larry car operator varied the loads as well: a few ore, a few coke, etc. This allowed for better combustion in the furnace.
Every once in a while… someone wasn’t paying attention and the operator would “put one in the hole.” When that happened, it was get out the shovels and manual
You have gotten some great replies so far but I will add a little more info for you.
A) A larry car is a self propelled car that carries raw materials in an integrated steel mill. Most are refering to the car that carries coal on top of the coke ovens, from the coal silo, across the tops of the ovens, to the next in line empty oven waiting to be filled with coal. The raw materials car that carries ore, coal, limestone on the highline of a blastfurnace is sometimes refered to as a larry car also.
B) I hear the new HO coke ovens from Walthers are going to contain the parts to build a larry car but, if you are like me and model N-scale you are on your own.
C) They go either on top of the coke ovens or run on the highline. Coal larrys, on top of coke ovens, go from the coal silos back and forth to dump coal in the top of the ovens. Raw material larrys go on the highline from the ore bins back and forth to the blast furnace raw materials storage bins.
Larry car in front of coal silo on top of coke ovens, Bethlehem Steel
Sorry danmerkel, didn’t mean to stiff your info on my post. I have always heard your Father’s type of car refered to as a “scale car” because it weighs the raw materials but I think it fits the definition of a larry car too.
Funny this subject should come up. I was just starting through my stack of old MR’s and came across this article on steel mills in the Nov. 1950. Granted the info is dated but its still accurate for the period.Perhaps its even better since not so much is imagined . The photos and diagrams are good and a nice little room size diagram is featured too,with all the various operations depicted.
Maybe MR has a way of getting this article out to you. BILL
To the best of my knowledge larry cars are no longer used at US blast furnaces. Conveyers are the method of choice for talking materials to the top of the blast furnace for a couple of reasons. A distribution of coke, iron ore and limetsone is required to prevent concentrations that do not react. In the last twenty years uniformity of taconite pellets including the addition of limestone in the pellet have reduced the need to mix products in the blast furnace. larry cars were used to weigh the iron ore and other products to keep them in ratio. The actual process is a reduction process since iron ore has a greater afinity for oxygen than carbon. So while some of the coke is there to provide the heat for an endothermic reaction some of it is there to provide carbon molecules for the oxygen in the iron ore to combine with leaving molten iron. One other thing that drives me nuts with Walthers. Slag cars are not used at blast furnaces. There is far too much of it. Every blast furnace has two very large pits behind or along side of it. When the iron is tapped in the cast house the slag is tapped on the back side into the slag pit. One is being filled while one is being emptied by a front end loader and off road dump trcuks who take it to a crusher facility, It takes as long as two weeks to completely empty one so the process is a fairly long one. The only furnace I know of that doesn’t work this way is #13 at Gary works of USX. They drop the slag directly into water which makes a very fine sand that is the hauled to a storage area for sale to end users.
This may be the case with newer furnaces but where Dad worked, I believe they were still in use just a few years ago. It may have something to do with the age of the mill; the blast furnace in Mingo dates back probably to the early 1900s but has undergone many modifications.
I don’t think they are using the rail cars any more but again, where Dad was, they had huge forklift type vehicles that picked up pots of slag & took them to the slag pit. The containers that they picked up looked “similar” to the containers that are on the Walthers cars. I think they called them thimbles.
I guess what I’m saying is that it would depend on several factors as to how you might accurately model a blast furnace… the era and the age of the furnace itself.
Keep in mind that there are also various sizes of “bottles” or “torpedoes” that the molten iron was put in. The Walthers models no doubt take advantage of some “selective compression” while the ones where Dad worked were full four-truck, 200-ton models. I think those are still in use as well… or at least they were. The mill where he worked has undergone some management changes and I’m not even sure if they are even producing iron there anymore.
Sorry for the confluximatation guys but my wife was thinking of a steelmill that she wanted to build as if it was in the 60’s or so. The mills would have had the details like mentioned by Dan—[#oops]
At the steel plant where I worked, the larry was the car used to charge the coke ovens, as shown in Spearo’s second photo. The term “larry” is a corruption of the word “lorry”, by the way.
The blast furnaces were fed from a stockhouse - regular in-plant railcars such as hoppers or ore cars ran atop it, emptying their loads into its bins. From there, raw material, as required, was dumped into a weigh car, which weighed the contents, then delivered them to the skip bridge, for transport to the top of the furnace.
The blast furnace slag was tapped to a slag pit, where it was cooled with water sprays, then loaded into trucks by power shovels (later by extremely large front-end loaders).
BOF slag was dumped in slagpots or thimbles - from at least the mid-'60s, these were moved by special rubber-tired vehicles to a slag dump - I never saw any of the rail-type. The Walthers blast furnace is a selectively compressed model of a very small furnace, btw - probably just as well, as a “to scale” version of a large one would dwarf most home layouts.
I, too, have worked in a steel mill. My lorry car for my coke oven was freelanced scratch built. Other machines for my coke oven were scratch built. I never got around to scratch building a quinch car, and now that Walthers will be selling them I can return my Difco car to MOW service. My loco for the quich car is just a Roundhouse “critter”.
The Larry Car carries crushed coal from the crusher to the coke ovens. In modern cases it sits on top of the ovens (Walthers has an upgraded coke oven with a Larry Car if you want to check the site). I have been sending them e-mails to release just the Lary Car.
