Steam Engines: The Why and How


| September/October 1990



Case

Fred Reckelberg's 1923 Case.

E2762 County F Kewaunee, Wisconsin 54216

Most of our club members and many spectators have a good understanding of the workings of the steam engine, but as time goes by we seem to reach an increasing number of people who are unfamiliar with them. This is understandable because few traction engines were manufactured after 1924, and steam engine use was largely replaced by that of the internal combustion engine by the middle 1930's. Because they were heavy and clumsy and moved very slowly on the road, because they damaged road surfaces and broke through bridges, and because they presented a constant fire hazard, their obvious advantages of cheap fuel and grease power were insufficient to warrant their continued use. The era of steam engine use for grain threshing was a relatively short one since some separators were driven by gas tractors as early as World War I, but saw mills continued to be run by steam power until a much later date. Slab wood and other mill waste made suitable fuel for the big steamers, and the stationary nature of the mill operation negated the need to move over surfaced roads. One man could serve as both fireman and engineer and a source of water could be piped directly to the engine tank. This left only the threat of fire as a drawback to the continued use of steam, but this was overcome by spark arresting smokestack caps or by conducting the exhaust into a high stack or chimney. At the present time, a few steam engines still power saw mills in northeastern Wisconsin, attesting to both their longevity and economy. Some saw mill engines were installed as stationary power plants, with masonry foundations and fireboxes, thus eliminating the expense of clutch, differential (compensating gear), and running gear, while others took the form of skid engines with runners in place of wheels.

For those unfamiliar with steam engines, a quick summary of their operation may be in order. Water is heated in an air-tight boiler having fire-flues extending through the water to increase heating surface and to enhance heat transfer. When the water boils, steam is produced and is drawn off at the steam dome which separates steam from water. The steam goes first through the governor valve which controls the top speed of the engine, and then through the throttle valve by which lower speeds can be selected. Steam next goes through the slide valve which times the intake and exhaust of steam into and out of the cylinder. Steam entering the cylinder moves the piston back and forth and turns the pulley through a crankshaft, while exhaust steam goes through a water heater to heat incoming boiler water and then exits up the smokestack to help induce draft for the fire.

Add to this a pump and/or injector to replenish boiler water, a lubricating system to feed water-soluble oil into the steam, a safety valve to prevent boiler explosion, a whistle to signal to the crew, and running gear and steering mechanism and you have a basic steam engine. Many other refinements appeared such as insulation to limit heat loss from the boiler, two cylinders to furnish more even power, use of compound cylinders to utilize more of the pressure left in the exhaust steam, and automatic controls to increase safety and lessen the need for constant attention. Entry of steam into the cylinder can be limited to certain parts of the piston travel, thus conserving steam when full power is not needed but when full speed must be maintained. The reverse lever will start and run the engines in either direction so reverse gears are not necessary.

The initial reaction to a first experience with steam power is one of amazement at the quietness of the operation; the second is a surprise at the great amount of power produced by a single cylinder. It should be pointed out that steam pushes the piston, at full power, through the full length of each direction of every stroke, not for just a part of every fourth stroke as in a gas engine. At one hundred pounds boiler pressure, a steam engine with a ten inch cylinder will have a constant force of about four tons acting on the piston. This translates into more than eighty horsepower which can be increased as needed by increasing the boiler pressure. Little wonder that this excellent source of farm power had such a profound impact upon the agricultural industry!

Many, many engines were broken up in the scrap drives during World War II but many, luckily, were saved. They have been restored by very special group of engine enthusiasts who have given freely of their time, talents, and resources to enable us to participate in this impressive sample of bygone years. They deserve our heartiest appreciation for saving this interesting part of our agricultural past for us to see. Although the heyday of steam use on the farm was a relatively brief one, it looms very large in the memory of our older members. The impact felt by the advent of this first large, portable source of farm power changed the whole future of agriculture, permitting the use of power-operated machinery, larger farm acreages and less manual labor. The opening of the midwest to large-scale cereal grain production for world markets was the direct result of steam plowing and threshing, and steam train and steamboat transportation. Thus, increases in farm food production during the first quarter to the present century can be traced directly to the use of the steam engine. Probably no other single invention had a greater share in developing the American farm to its present number one position in world food production.