Unit 2 steam engines: developments of the industrial revolution
LEAD-IN
Think of as many words as possible related to the topic “Development of steam engines”. How important were steam engines in the industrial revolution?
Study the diagram of James Watt’s pumping engine. How did the separate condenser which he had added to the earlier design make the steam engine more effective?
3. Read the text and decide whether the statements that follow are true or false. Steam engines: developments of the industrial revolution
The rapid growth of industry in Britain from about the mid-18th century (and somewhat later in various other countries) created a need for new sources of motive power, particularly those independent of geographic location and weather conditions. This situation, together with certain other factors, set the stage for the development and widespread use of the steam engine, the first practical device for converting thermal energy to mechanical energy.
The foundations for the use of steam power are often traced to the experimental work of the French physicist Denis Papin. In 1679 Papin invented a type of pressure cooker, a closed vessel with a tightly fitting lid that confined steam until high pressure was generated. Observing that the steam in the vessel raised the lid, he conceived the idea of using steam to power a piston and cylinder engine.
Thomas Savery, an English inventor and military engineer, studied Papin's work and built a steam-driven suction machine for removing water from coal mines. Savery’s machine (patented in 1698) consisted of a boiler, a closed, water-filled reservoir, and a series of valves. Steam was introduced into the reservoir, and the pressure of the steam forced the water out through a one-way outlet valve until the vessel was empty. Water was then sprayed over the surface of the vessel to condense the steam and create a vacuum capable of drawing up more water through a valve below. Unfortunately the vacuum created was not perfect, and so water could only be lifted to a limited height.
NEWCOMEN ENGINE
Some years later another English engineer, Thomas Newcomen, developed a more efficient steam pump consisting of a cylinder fitted with a piston – a design inspired by Papin's aforementioned idea. When the cylinder was filled with steam, a counterweighted pump plunger moved the piston to the extreme upper end of the stroke. With the admission of cooling water, the steam condensed, creating a vacuum. The atmospheric pressure in the mine acted on the piston and caused it to move down in the cylinder, and the pump plunger was lifted by the resulting force.
Because Savery had obtained a broad patent for his steam device, Newcomen could not patent his engine. He thus entered into a partnership with Savery, and together they built, in 1712, the first piston-operated steam pump. Several years later Smeaton improved the Newcomen engine, almost doubling its efficiency. Although engines of this kind converted only about 1 percent of the thermal energy in the steam to mechanical energy, they remained unrivaled for more than 50 years.
WATT’S ENGINE
In 1765 James Watt, a Scottish instrument maker and inventor, modified a Newcomen engine by adding a separate condenser to make it unnecessary to heat and cool the cylinder with each stroke. Because the cylinder and piston remained at steam temperature while the engine was operating, fuel costs dropped by about 75 percent.
Watt entered into a partnership with Matthew Boulton, who owned a factory in Soho, near Birmingham, England. At Boulton’s insistence he set out to develop a new kind of engine that rotated a shaft instead of providing simple up-and-down motion. He found a way to obtain an inflexible connection between piston and rod (beam) and invented special gear arrangements to convert the up-and-down movement of the beam into circular motion. A heavy flywheel was added to smooth out the variations in the force delivered to the engine shaft by the action of the piston in the cylinder. The flow of steam to the engine was regulated by a governor connected to the flywheel. In addition, Watt applied steam to both sides of the piston to produce greater uniformity of effort and increased power.
Although far more difficult to build, Watt’s rotative engine opened up an entirely new field of application: it enabled the steam engine to be used to operate rotary machines in factories and cotton mills. The rotative engine was widely adopted; it is estimated that by 1800 Watt and Boulton had built 500 engines, of which less than 40 percent were pumps and the rest were of the rotative type.
From Encyclopædia Britannica
1. New sources of motive power were necessary for the rapid development of industry in Britain in the mid-18th century.
2. Steam engines transform thermal energy to mechanical energy.
3. Denis Papin invented the first steam engine.
4. The first steam-driven suction machine for removing water from coal mines was designed by Thomas Savery.
5. Savery’s engine was used to lift water to any height.
6. Thomas Newcomen improved the earlier steam engine.
7. The Newcomen engine was highly effective.
8. The major improvement of the steam engine made by Watt’s was a separate condenser.
9. Watt’s engine sufficiently saved fuel consumption.
10. James Watt and Matthew Boulton designed an engine that provided simple up-and-down motion.
11. Watt’s engine was widely used in factories.
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