Monday, December 15, 2014

WASHING MACHINE




Earlier, people used to clean their clothes by pounding them on hard rocks or scrubbing them with abrasive sands and wash away the dirt in rivers or lakes. Later, washboards were developed that helped streamline the process. Bleaching was necessary even back in Roman times. In order to have the whitest whites, clothing was taken to a "fuller" who put the clothing in a tub of fermented urine and agitate the clothing with his feet. For centuries, people on sea voyages washed their clothes by placing the dirty laundry in a strong cloth bag, and tossing it overboard, letting the ship drag the bag for hours. This forces water through clothes to remove dirt.
But washing clothes this way took a lot of time and efforts also. There was an obvious need for technology to make it easier to get clothing clean more quickly.
 The first washing machine was called as the scrub board invented in the year 1797. The agitation of the clothing was necessary to get it clean. So the washing machines were hand operated when electricity was not available to all.
In 1851, American James King discovered and patented the first washing machine to use a drum. However it was still hand powered and did not work by itself.
Then in 1858, William Blackstone of Indiana built a washing machine for his wife. This washing machine removed and washed away dirt from the clothes. This was the first official washing machine that could be used at home.
Early washing machines were made from wood but later on they were made from metal. The metal machines could have a fire built under them to keep the water conveniently hot for each load of clothing. The wringing process was made quicker and easier with the help of rollers and wringers but it still took a very long time.

Electricity was not commonly available to all homes until 1930 or so. Washing machines that were automatic rather than cranked by hand often run on a single cylinder, gasoline powered engine.
In 1908, Hurley Machine Company of Chicago invented the Thor machine. This was the first washing machine that was electric-powered and had a galvanized tub and an electric motor. The earlier washing machines had heavy, cast-iron mechanism mounted on the tub lid. This made the washing machine heavier and bulky.
By 1920 the production of coppered wooden tub completely stopped. Also, the machine made lot of noise because of the bulky metal tub. The tub was now copper ribbed and made of metals like nickel or nickel-chromium plated. Another modification that was made was covering the tubs with white enamelled sheet metal to make cleaning process easier.
From a technological perspective, washing machine manufacturers faced a number of challenges. These included discovering a method of transferring power from the motor to the mechanism, finding a suitable motor with sufficient initial starting torque, and ensuring that the operator did not get an electrical shock during operation.
In the transference of power, some washing machines were chain driven, some belt driven and others used shafts and gears.

To overcome the initial resistance in starting a washing machine, a fractional horsepower motor which would not burn out or overheat during the start-up period was used. This was usually a 1/8 or ¼ horsepower motor, manufactured out-of-house by Westinghouse or Robbins and Myers.
To prevent electric shocks, the stator and rotor of the machine were enclosed in a housing equipped with a fan to prevent overheating. From the customer satisfaction perspective, a machine that would wash without shredding the clothes needed to be developed. This meant that if the original scrubbing machines were used, the machine had to be operated at different speeds for different textiles. To overcome the problem, washing machines that sloshed water through the clothing by agitation were developed. Either the tub moved or a baffle placed inside the tub moved.

In 1937, Bendix received the patent for and introduced the first fully automatic washing machine.
In 1947, General Electric introduced the first top loading automatic washing machine. This machine had many of the same features found in modern machines. It was equipped with 5 push buttons to control wash temperature, rinse temperature, agitation speed and spin speed.
In the 1950s the mechanical timer was developed and simplified clothes washing for the homemaker. Washing machines did not change much for the next forty years.
In the 1990s James Dyson created a washing machine that had two cylinders rotating in opposite directions. This was said to make the clothes cleaner and shorten wash time.
In 1994 Staber Industries introduced the System 2000 washing machine. It is a top loading, horizontal axis washer. Because the tub spins like a front loading machine it uses only about one third of the water normally used by a washing machine.
In 2006 Sanyo introduced a washing machine that uses only 50 L of water because it recycles the water used.
In 2008, the University of Leeds created a prototype machine that used only one cup of water per load of laundry. This would save huge amounts of water every year.





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