Go dry up

Water resources are scarce, so sweepers try to do without

Article August 16, 2003
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Hardly a day goes by without news about drought or lack of water resources in some part of the U.S. Yard watering bans and car washing restrictions are taken as a fact of life in many areas. Water for crop irrigation is becoming scarce.

Few people realize that a street sweeper that is operating properly without generating a cloud of dust can consume 1,500 gal of water a day. The street sweepers in use in the Los Angeles basin alone can consume nearly 1.5 million gal of water per day. That is fresh processed water that’s spread on the ground simply to reduce airborne dust.

If the water isn’t used for dust suppression, the dust that’s raised contributes to particulate matter (PM) air pollution. This pollution problem has been officially identified and classified by the EPA in 59 regions of the U.S. These areas have a combined population of more than 29 million people.

The good news is that water is no longer the only means of controlling sweeper-generated dust. The advent of “Waterless Dust Controlled” sweepers has introduced the possibility of sweeping dust free with no water usage.

Waterless-dust-control sweepers are typically classified as “combination” sweepers. The brooms are enclosed within flexible shrouds that prevent the dust from escaping. A powerful vacuum fan on the sweeper sucks the dust into the debris hopper where it is allowed to settle out with the rest of the debris.

The advantages of this type of combination system include greatly reduced water usage; reduced air pollution because of improved sweeping efficiency; reduction of silt that can contribute to storm-water pollution; and the ability to sweep in freezing weather.

The systems require a larger engine to operate the vacuum fan in conjunction with the broom sweeping system. Also, the vacuum system adds to the cost of the sweeper. However it has been shown that the slight increase in sweeper cost is offset by a 20% increase in productivity because there is no need to make frequent stops to refill with water; less time required to clean and maintain the sweeper because it is not caked with mud; and improved component life because moving components don’t have to work in mud.

Products

What follows are brief descriptions of a few of the latest street sweeper products.

Wading in

The Waterless Eagle and Waterless Pelican (Circle 936) from Elgin Sweeper Co., Elgin, Ill., represent the latest in sweeping technology with their ability to handle all types of sweeping conditions and applications without the need to spray water for dust control. The dust control system operates efficiently at all normal sweeping speeds and conditions. Patent-pending fan and filter technology minimizes filter loading and extends filter cleaning intervals. Fully flexible main and side broom skirting allow efficient dust capture while still allowing aggressive curb cleaning. For times that wet dust control is desired, a full water system is available.

Engineered dust free

The Centurion Street Sweeper is a dry street sweeper specifically designed to help cities meet their EPA Phase II and PM10 requirements. Featuring a unique, StreetSmart sweeping system that effectively traps and controls dust without water, the Centurion (Circle 937) from Tennant Co., Minneapolis, operates year-round, even in cold climates. To maximize sweeping time, the Centurion features an extra-large hopper (50% larger on average) and handles a full range of debris, including routine dirt and dust and construction waste such as milling and chip seal. The Centurion also features numerous operator comforts, such as simple, one-button sweeping, allowing the operator to concentrate on the road.

Unstainable

Masco Sweepers Inc., Santa Clara, Calif., manufactures truck-mounted vacuum parking lot sweepers, street sweepers, airport runway sweepers and magnet sweepers. Masco’s line of vacuum parking lot sweepers includes the popular 2200 that slides into a pickup truck, the 2-yd Econo 2000 sweeper, the 3-yd Tundra 1600 sweeper with a stainless steel hopper and the Diesel 5000 5-yd sweeper also with a stainless steel hopper.

The Husky (Circle 938) 4-yd broom street sweeper is the company’s newest model. This sweeper is quiet, powerful and can dump over 9 ft high. The Husky uses proven and dependable tandem gear pumps to hydraulically drive the main and gutter brooms, elevator and hopper dump. The Eliminator, Sweeprite’s patented 58-in. main broom, uses angled-forward leading edges to virtually eliminate streaking and pick up more debris, dirt and trash. The Husky’s water system puts water at the tip of the gutter broom bristles to keep dust to a minimum and use less water.

Whispering fan

All the regenerative air sweepers from Schwarze Industries Inc., Huntsville, Ala., are equipped with the company’s WhisperWheel fan system. WhisperWheel reduces air sweeper noise by more than 70% while increasing power 7% and decreasing sweeper fuel usage by 20%. The sweepers range in capacity from the 4.3-cu-yd A4000 to the 9.6-cu-yd A9000. In between are the 8.4-cu-yd A7000 and the 5.8-cu-yd A8000, which offers variable high dumping from 36 to 118 in. The A7000 (Circle 939) is available in diesel or CNG models or mounted on a UNIMOG chassis. The A7000’s blower system generates a high-velocity air column that is directed against the pavement at an angle to peel debris off the surface. To ensure minimal dust escape, double-belted curtains on the front and rear of the sweeping head contain the circulating air flow.

Compact sweeper

The sight lines from the operator’s seat of the CN100 Sub-Compact Sweeper are “unprecedented,” according to Madvac Inc., Boucherville, Quebec. The CN100 (Circle 940) has a variable sweep path of 44-88 in. wide, a road speed of up to 16 mph and a three-stage dust filtering system. A stainless steel debris container resists abrasion and corrosion. It effectively sweeps and vacuums a variety of surfaces, including streets, alleys, city sidewalks and parking lots.

Hydraulic sweeping

The sweepers from Nite-Hawk Sweepers, Kent, Wash., work without an auxiliary engine, so the hydraulic system emits no pollution, saves fuel and needs less maintenance. The NH400 (Circle 941) has a 4-cu-yd hopper and comes mounted on either a conventional or cab-over diesel chassis. The dump height of 67 in. and 92° dump angle make it easy to empty the hopper quickly and completely. All of Nite-Hawk’s sweepers come standard with powder-coated exteriors, air conditioning, AM/FM stereo, an 81-in. pick-up head and a driver’s side curb blower.

Leaves come in

An operator-controlled leaf door allows easy ingestion of heavy leaf accumulations by the model 3000 and 4000 mechanical broom street sweepers from Johnston Sweeper Co., Chino, Calif. The 3000 and 4000 (Circle 942) are hydrostatic mechanical machines available in three- and four-wheel configurations. The leaf door features a hydraulically operated lower elevator panel that can be raised or lowered at the touch of a switch. It allows the leaves to enter the elevator without being ploughed ahead, thereby increasing sweeping productivity.

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