by Eric Flint
Developed in China during the Cultural Revolution (1960s), there are thousands of VSBKs in rural China. In more recent years Chinese engineers have been introducing the technology to their neighbors. Since the start of the 1990s VSBKs have been built with Chinese assistance in Pakistan, India, Bangladesh, Nepal, Vietnam, and probably other countries. The VSBK is cheap and easy to build, and can be built in six weeks using mostly down-time materials and labor. The single up-time contribution, assuming down-timers can't make sufficiently strong ones, is a screw jack per shaft capable of lifting a five-meter stack of bricks (up to thirty tons). Even the amount of information needed to build the VSBK is small, with a group in Nicaragua building a single shaft VSBK based only on information gained from the Internet. Production in the kiln is up to about seven thousand bricks per day per shaft, and VSBKs with as many as six shafts have been built. They can't compete on volume with the bigger Bull's Trench and Hoffmann kilns, however they are significantly more economical to run, and they have significantly fewer failures. Because the fuel is added to the green bricks the fuel undergoes the same drying and warming process as the bricks. This is what makes the VSBK so suitable for firing using the wet coal to be found in Germany. Other kiln designs introduce the fuel directly into the fire zone. They need dry fuel, otherwise heat will be wasted to dry and heat the coal. Meanwhile, the VSBK uses waste heat to achieve the same result. No other kiln design is going to be as economical to fire using the wet coals.
There is of course a downside to the VSBK. As they have to be able to withstand being stacked five meters high in the firing shaft, good quality green bricks are a necessity. Green bricks have to be lifted (or wheeled up a ramp) to the top of the tower, and then carefully placed in the top of the stack. The big problem is the twenty-four hours a day, seven days a week running of the kiln. Whereas all the other kilns need little more than monitoring of the fire during the night hours, the VSBK needs to have batches loaded and unloaded at regular intervals. Ideally, batches of bricks are removed from the bottom of the stack every sixty to ninety minutes, although in practice three to four batches are often removed at one time. This means, that for continuous operation, a source of light for the night shift is required. In a multishaft VSBK the workers can be busy right through their shift unloading from the bottom and reloading at the top.
The number of batches and the time of unloading are decided by the fire master, who uses his experience to judge when bricks are ready by the color and position of the firing zone in the shaft. This means that the fire master needs to be a skilled individual for the production of good quality bricks. The cost of poor skills in the few areas needing them can be seen in the failure rates in different countries. China has about two percent failures, India, where Chinese engineers ensured the staff was properly trained, have about a five-percent failure rate. Pakistan, where the Chinese engineers left without giving proper training, the failure rate is about twelve percent, about the same as that of the much cheaper to build Bull's Trench.
It is unlikely that anyone in the Ring of Fire has ever worked on a VSBK. It is also doubtful that anyone in the area has anything, photographs, drawings, or even downloads from the Internet, on the VSBK. There is a limited possibility that someone might have seen a VSBK in operation in Asia or Nicaragua. However, as the design concept is so simple, I think that if someone has ever walked over a VSBK and seen one in operation, that person will have sufficient information for skilled up- and down-timers to develop a design.
4b) Shuttles and kiln productivity
Having decided on the design of our kiln, what else can we do to improve productivity? One area is reducing turn-around time. In most kilns bricks are hand set, and also removed by hand. This means that both the kiln chamber and the bricks must be sufficiently cool for humans to work. However, economics rears its ugly head once again. Every degree the kiln cools is another degree the brickmaker has to expend fuel to recover. This means workers will be sent into the chamber to unload as soon as the conditions are bearable. Then we have brick setters working in confined spaces with poor illumination as they race to empty the fired batch and reload the chamber as quickly as possible. There is a way around the problem however. We can use shuttles or trolleys. A shuttle is a cart with a metal frame and metal wheels, and decked with brick, often firebrick. Green brick is set on a waiting shuttle outside the kiln. When a batch of bricks is finished being fired and cooled to a safe temperature (such that it won't crack when exposed directly to normal air temperature) it is simply wheeled out, and the new batch wheeled back in its place. Not only can setting and unloading be done in the open and relative cool, but the kiln is out of service for a much shorter period of time and doesn't lose as much heat. By using shuttles, handling of green and fired brick and the associated costs can be reduced considerably.
Shuttles can not be used in clamps, scoves, Scotch kilns or most up-draft kilns. Either the uncontrolled nature of the firing or the fact that the fire must pass up through the brick means they are not suitable techniques. Down-draft kilns (and their close cousin, the cross-draft kiln) can use shuttles. The Bull's Trench kiln, because of the hole-in-the-ground nature of the design, is not suitable for using shuttles, besides, the open air nature of the loading and unloading removes many of the benefits available. The tunnel kiln, of course, needs shuttles to carry the bricks through the tunnel. The VSBK does actually have a place for the shuttle, although its shuttle doesn't need to be decked with brick. The VSBK is unloaded by lifting the loading deck of a trolley up to the bottom of the stack of bricks using a screw jack. Once in contact with the stack of bricks the steel poles holding the mass of bricks are removed and the trolley is slowly lowered until the next specially arranged layer of bricks appears. The steel bars are once again threaded through the gaps in the rows of bricks and the trolley is slowly lowered until the poles once again rest on a pair of heavy steel girders on either edge of the shaft. With the weight of the shaft of bricks taken on the girders, the trolley is lowered to the ground and wheeled out.
Conclusion
Unless they are prepared to spend a lot of time and resources to develop the knowledge base, up-timers will need down-timers to provide the detailed knowledge of clay and firing if they want bricks. Up-timer technology and knowledge would help down-timers increase brick production, but a simple increase in demand for brick will be sufficient motivation for down-timers to develop improvements. Put bluntly, we need down-timers; they don't need us.
Who in Grantville will have the knowledge that will help the great step forward in brick production? We know there are going to be people in the Ring of Fire area who are potters or ceramic artists. For a start, on the grid of up-timers, we have Garth Freeman and his wife Melba Sue. They have "... a very elaborate ceramics and pottery setup." This is sufficient to suggest they have at least one kiln, and some clay preparation machinery, such as a pug mill. This being West Virginia, they probably built both the kiln and the pug mill themselves. This suggests that they have books and magazines describing kilns, ceramics, and machines for preparing clay. Also, Grantville is set in an area of West Virginia were ceramics were manufactured. There is good clay inside the Ring of Fire, maybe even China clay (suitable for porcelain), for this reason Garth and Melba Sue won't be the only people in the Ring of Fire area who are into ceramics.
The small hobby ceramic artists and potters can get the industry started, but when it comes to the heavy extrusion machinery, specialist books will be desirable. This brings us to the late George Bowers. George died in about 1945, however his legacy survived through his daughters until June 2000, when his accumulated collection was auctioned off. George is important to us because he made his fortune from the manufacture of ceramics (mainly bathroom porcelain). The earths around Grantville can be assumed to be similar to those around Mannington where George made his fortune. It is reasonable to assume that, although George's massive collection of books (some twenty thousand volumes on a range of topics) does not
exist in Grantville, someone in Grantville is likely to have some of the same turn of the century ceramics books and treatise on brickmaking that George might have had.
Overall the prospects for the Grantville brickmaker are favorable. If they can find a down-time master brickmaker to do the hard work of selecting the clay and judging the firing of the bricks, there is sufficient knowledge within Grantville to rapidly increase the supply of bricks. Even without the advantage of reference material, the brick extruder should be developed. Knowing bricks were made with an extruder will be sufficient to set inventive minds on the right track. The idea of using shuttles should be obvious, as nobody really likes double handling of goods when they don't have to. It is in the design of kilns where Grantville will have to be lucky. With all those chambers that have to be built to take high temperatures, the full Hoffmann kiln is going to be expensive to build. Either someone is going to have to suggest making a smaller version of the Hoffmann (say, four chambers set in a square), or someone is going to have to know about the tunnel kiln, or better yet the VSBK. The Tunnel kiln is likely to be thought of, but it is going to be expensive to make all those trolleys. Also, it is less efficient than an equivalent capacity Hoffmann kiln. I still like the VSBK because it is cheap to build and run; also it can easily be constructed with down-time resources. All it needs is someone to have seen one in operation, or to have done a little research on them for some reason.
Glossary:
Burnt: Bricks are burnt or fired in a kiln. It doesn't mean they have anything wrong with them.
Clot: A clot of clay is a tempered lump of clay that is thrown into a brick mold. Ideally a thrown clot of clay will just fill the mold.
Continuous kiln: A kiln where the fire is kept going. The fire may move through the kiln complex, or remain stationary letting the bricks pass through the fire zone, but the fire never goes out.
Earth(s): The technical term used to refer to soils as opposed to rocks.
Extruded brick: When clay is forced through the end of a pug mill in the form of a continuous block which is then cut into small slices using wire cutters, those slices are called extruded brick. The size and shape of the nozzle defines the shape of the block extruded and thus the shape of the brick.
Fired: Bricks are fired, as in, exposed to the heat of the fire. See also "burnt."
Fire zone: Where ever the fire is burning in a continuous kiln. The fire zone can move from chamber to chamber or stay in one place.
Frog: Another name for the "kick."
Green brick: Brick that has been molded to shape, but has not yet been fired. With the addition of a little water, and a little hard work, plasticity can be restored to the clay in a green brick.
Grog: Take a broken previously fired brick or other piece of ceramic, grind it up, and use it as a filler. Grog does not regain plasticity and will not undergo chemical change when re-fired. Grog is useful for padding out supplies of expensive clay, or when the available clay needs certain additives.
Hack: To closely stack drying bricks edge on top of edge. Usually the stacks are arranged with about a finger-width distance between them. They are then left to dry a little longer. A hacking ground is an area where bricks are hacked (stacked).
Intermittent kilns: Kilns where the fire is lit anew for the firing of each separate batch.
Kick: The insert in a brick mold that causes a depression or hollow to be formed in the top of a brick. Often the brickmaker will have his name, or his company's name set into the kick. The kick helps force thrown clay into the bottom corners of the mold.
Mellowed: Made pliable and plastic, usually by tempering.
Pallet: A board sufficiently large enough to hold a single brick with space left over. For a 9" x 4.5" x 3" the pallet would be something like 12" x 8".
Plastic: This describes the condition of properly tempered clay. It can be easily worked (shaped and reshaped). If left alone it will hold its shape sufficiently long to be fired.
Setting: The careful stacking of bricks within a kiln so that they will be properly fired.
Strike: Basically a piece of wood with a straight edge that is used to smooth off any excess clay from the top of the mold
Tempering: The art of making clay plastic and pliable by breaking it down so that water is in contact with every molecule of clay.
References:
Daniel Rhodes (1968). Kilns: Design, Construction, and Operations.
As the title suggests, a book telling the ceramics worker the history of kilns, how to design a kiln, build it, and run it. The book also provides plans for a selection of small ceramics kiln. Almost a must have for the Grantville home ceramic artist.
Edward Dobson (1903) (11th ed.). A Rudimentary Treatise on the Manufacture of Bricks and Tiles Containing an Outline of the Principles of Brickmaking.
This book examines brickmaking in England. It provides good descriptions of the process and also includes illustrations of many of machines for tempering clay and extruding bricks and sewer pipe.
Charles Thomas Davis (1895) (3rd ed.). A Practical Treatise on the Manufacture of Bricks, Tiles, and Terra Cotta:
This book describes the industry in America. It fully covers brickmaking, the machines that can be used, and many of the kilns.
Alfred B. Searle (1924) (2nd ed.). Refractory Materials: Their Manufacture and Uses.
Searle examines the refractory industry in England and Wales. There is a lot of information on where to find the various fireclays, and how to mix them for desired refractories.
Colonial Williamsburg Brickyard: Eighteenth Century Brickmaking in the USA.
http://www.history.org/Almanack/life/trades/tradebri.cfm
Vertical Stack Brick Kilns (VSBK)
http://www.gtz.de/basin/gate/vertical.htm
http://www.vsbkindia.com/
The Vertical Shaft Brick Kiln (VSBK) In Nicaragua
http://solstice.crest.org/discussiongroups/resources/stoves/Martirena/THE%20VSBK%20IN%20NICARAGUA.htm
An article on a group constructing a VSBK in Nicaragua using only the information they can find on the internet and in a few pamphlets. There are a few good photographs of the VSBK being built.
Brick Clamps
http://www.gtz.de/basin/gate/brickclamps.htm
Hoffmann Kiln
http://www.gtz.de/basin/gate/HoffmannKilns.htm
Bull's Trench Kiln
http://www.gtz.de/basin/gate/bull.htm
Clay Preparation
http://www.gtz.de/basin/gate/tb11/clayprep.zip
Clay Drying
http://www.gtz.de/basin/gate/tb12/claydrying.zip
Clay Firing
http://www.gtz.de/basin/gate/tb13/clayfiring.zip
Clay Molding
http://www.gtz.de/basin/gate/tb15/ClayMoulding.ZIP
Lots of other interesting documents on brickmaking.
http://www.gtz.de/basin/publications/wall.htm
A history of Isle of Wight Brickmaking
http://freespace.virgin.net/roger.hewitt/iwias/bricks.htm
IMAGES
Note from Editor:
There are various images, mostly portraits from the time, which illustrate different aspects of the 1632 universe. In the first issue of the Grantville Gazette, I included those with the volume itself. Since that created downloading problems for some people, however, I've separated all the images and they will be maintained and expanded on their own schedule.
If you're interested, you can look at the images and my accompanying commentary at no extra cost. They are set up in the Baen Free Library. You can find them as follows:
1) Go to www.baen.com
2) Select "Free Library" from the blue menu at the top.
3) Once in the Library, select "The Authors" from the yellow menu on the left.
4) Once in "The Authors," select "Eric Flint."
5) Then select "Images from the Grantville Gazette."
SUBMISSIONS TO THE MAGAZINE
If anyone is interested in sub
mitting stories or articles for future issues of the Grantville Gazette, you are welcome to do so. But you must follow a certain procedure:
1) All stories and articles must first be posted in a conference in Baen's Bar set aside for the purpose, called "1632 Slush." Do not send them to me directly, because I won't read them. It's good idea to submit a sketch of your story to the conference first, since people there will likely spot any major problems that you overlooked. That can wind up saving you a lot of wasted work.
