Street sweeper

This article is about devices for cleaning streets. For the shotgun, see Armsel Striker.
"Sweepers" redirects here. For the 1998 film, see Sweepers (film).
A compact street sweeper tackles litter in Mexico City
Street sweeper in Paseo de la Reforma in Mexico City

A street sweeper or street cleaner may refer to a person's occupation, or a machine that cleans streets. A street sweeper cleans the streets, usually in an urban area.

Street sweepers have been employed in cities since sanitation and waste removal became a priority. A street-sweeping person would use a broom and shovel to clean off litter, animal waste and filth that accumulated on streets. Later, water hoses were used to wash the streets.

Machines were created in the 19th century to do the job more efficiently. Today, modern street sweepers are mounted on truck bodies and can vacuum debris that accumulates in streets.

History

Mechanical sweepers in the United Kingdom

Mechanical street sweeper by Joseph Whitworth
Monument of street sweeper in St. Petersburg, in Russia

By the 1840s, Manchester, England, had become known as the first industrial city. Manchester was home to the first passenger rail service in the world and had one of the largest textile industries of that time. As a result, the robust metropolis was said to be England’s unhealthiest place to live.[1] In response to this unsanitary environment, Joseph Whitworth invented the mechanical street sweeper. The street sweeper was designed with the primary objective to remove trash from streets in order to maintain aesthetic goals and safety.[2][3]

Mechanical sweepers in the United States

The very first street sweeping machine was patented in 1849 by its inventor, C.S. Bishop. For a long time, street sweepers were just rotating disks covered with wire bristles. These rotating disks served as mechanical brooms that swept the dirt on the streets.[4]

Charles B. Brooks, an African American man from Newark, New Jersey, invented the U.S.' first self-propelled street sweeper truck. Brooks' patent was approved on March 17, 1896; his application for the patent had been filed on April 20, 1895. His street sweeper had a truck-like frame mounted on axles supported by wheels. There are drive-wheels for the sweeping, elevator mechanisms, and an endless chain that travels around a sprocket-wheel and travels up to an additional sprocket-wheel. The patent drawings go on to explain the complete composition of the invention. The truck had brushes attached to the front fender which would revolve. These revolving brushes could interchange with a flat scraper for use on snow and ice.

John M. Murphy called at the offices of American Tower and Tank Company in Elgin, Illinois, in the fall of 1911. He had a plan of a motor driven pickup street sweeper. The American Tower and Tank Company had been formed in 1903 by Charles A. Whiting and James Todd. They called in a recently acquired silent partner, Daniel M. Todd, and it was decided to hire Mr. Murphy and begin the development of his idea. That started what has become the Elgin Sweeper Company.[5]

After two years of trial, development, experimentation, and research, a sweeper was achieved which Murphy was satisfied performed all of the sweeping functions in the manner he had envisioned – one which partners James and Daniel M. Todd and Charles A. Whiting were willing to risk a reputation gained from 30 years manufacturing experience.[5]

In the fall of 1913, the City of Boise, Idaho, purchased the first Elgin Sweeper, following a demonstration. Boise Street Commissioner, Thomas Finegan, made a comparison showing a savings of $2,716.77 from the Elgin motorized sweeper when used rather than a horse-drawn sweeper.[5]

Following its introduction and initial sales, John M. Murphy continued the perfection of his sweeper. In 1917, US patents were filed and issues for J. M. Murphy, Street Sweeping machine #1,239,293.[5]

Technological advancement

The goal of simple debris removal did not change until the 1970s, when policymakers begun to reflect concern for water quality. In the United States, The lag time in which street sweepers responded can be pinpointed to the Runoff Report of 1998.[6] As older street sweepers were only effective in removing large particles of road debris, small particles of debris remained behind in large quantities.[7] The remaining debris was not seen as an aesthetic issue because rain would wash them away. Today, small particles are known to carry a substantial portion of the stormwater pollutant load.

Street sweeping can be an effective measure in reducing pollutants in stormwater runoff.[8] The Environmental Protection Agency considers street sweeping a Best Management Practice in protecting water quality.

Modern sweepers

Newer mechanical street sweeper in Ohio
Walk behind street sweeper is used to clean a sidewalk alongside pedestrians

Newer street sweepers are capable of collecting small particles of debris.[9] Many street sweepers produced today are PM10 certified,[10] meaning that they are capable of collecting and holding particulate matter sized less than 10μm.[11] Despite advancements in street sweeping technology, the mechanical broom type street sweeper accounts for approximately 90 percent of all street sweepers used in the United States today.[12]

Modern street sweepers are equipped with water tanks and sprayers used to loosen particles and reduce dust. The brooms gather debris into a main collection area from which it is vacuumed and pumped into a collection bin or hopper.

A regenerative air street sweeper uses forced air to create a swirling effect inside a contained sweeping head and then uses the negative pressure on the suction side to place the road debris inside a hopper. Debris is removed from the air by centrifugal separation, keeping particulate matter inside the hopper.[13] Many regenerative air sweepers are AQMD certified by their manufacturers and can pick up particles as small as 10 micrometres or less (PM10), a leading cause of stormwater pollution.

However a modern regenerative air street sweeper faces the challenge of noise level due to the fact that regenerative air street sweeper requires an extra engine to power the vacuum pump required to create the negative pressure for placing debris into a hopper.

Modern machines can cost $US300,000 each and a large city can remove upwards of 18,000 tons of materials annually via its fleet of sweepers. If poorly maintained, modern sweepers can have very poor cleaning performance.[14]

Modern sweepers in Asia

Green Star Mech Sweeper Taipei Port 2012

Sweeper manufacturers in Asia have also developed less sophisticated mechanical and regenerative air sweepers which differ in design to the American and European sweepers. China and Taiwan have both adapted the mechanical sweeper design of using two main brooms mounted vertically at the back of the hopper to carry debris into hopper. This design is less complicated and more cost effective than the mechanical belt and broom setup.

See also

References

  1. ↑ http://www.macalester.edu/courses/geog61/manchester/history.htm
  2. ↑ Pitt R, Bannerman R, Sutherland R, 2004. The role of street cleaning in stormwater management, Environmental and Water Resources Institute of the American Society of Civil Engineers. 1-8
  3. ↑ Chang Y, Chou C, Su K, Tseng C, 2004. Effectiveness of street sweeping and washing for controlling ambient TSP, Atmospheric Environment, 39: 1891–1902
  4. ↑ http://www.articlesinsight.com/Art/5752/191/The-many-Different-Sweepers-And-Machines-Used-In-Street-Sweeping.html
  5. 1 2 3 4 (Source of Historic Information, The Sweep of Time by William A. Richman Copyright, William A. Richman, 1962) (Information taken from published book)
  6. ↑ "Results of the Nationwide Urban Runoff Program" (PDF). Environmental Protection Agency. Retrieved 2013-12-16.
  7. ↑ German, J.; Svensson, G. (2002). "Metal content and particle size distribution of street sediments and street sweeping waste". Water Science and Technology. 46 (6-7): 191–198. Archived from the original on 2013-12-17.
  8. ↑ EPA - Stormwater Menu of BMPs
  9. ↑ Pitt, 2004
  10. ↑ Chang, 2004
  11. ↑ PM-10 Efficient Street Sweepers
  12. ↑ Wildlife and Habitat | Ecosystems | Environmental Review Toolkit | FHWA
  13. ↑ "How The Regenerative Air System Works". Tymco. Retrieved 11 March 2016.
  14. ↑ Donovan, Kevin (8 October 2014). "Poorly maintained Toronto street sweepers can't do dirty work". Toronto Star. TorStar. Retrieved 8 October 2014.
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