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7.1.D. - Page 11
<br /> US 6,627,089 B1
<br /> 1 2
<br /> WATER MAIN RECIRCULATING/ unless the amount of residual chlorine is reduced to less than
<br /> FILTERING/FLUSHING SYSTEM AND 0.1 mg/liter.In the past,this was either not done or,when
<br /> METHOD done, was attempted by injecting sodium sulfite into the
<br /> discharge stream.This is a difficult process to perform and
<br /> 5 monitor because it is necessary to dispense sodium sulfite in
<br /> BACKGROUND OF THE INVENTION controlled amounts according to the volume of water being
<br /> 1. Field of the Invention treated.If there is too much sodium sulfite,it can itself cause
<br /> pollution problems by interfering with pH levels and if the
<br /> The present invention relates to a method and equipment amount is insufficient, there will be excessive residual
<br /> for flushing a water main and in particular to a pump and io chlorine. It has been found that the injection approach
<br /> filter system and method of flushing a section of water main requires not only highly skilled personnel, but extensive
<br /> between hydrants filtering the sediment and particulates out training. Moreover,the end result is unpredictable.
<br /> of the water and recirculating it back into the water main While some attempts have been made at improving water
<br /> without wasting the water. main flushing systems,the real problems of water waste and
<br /> 2.Description of the Prior Art 15 water quality still remain to be addressed.
<br /> Almost all water providers are required to have their U.S.Pat. No. 6,227,463, issued May 8,2001 to Porter,
<br /> mains large enough to provide a sufficient flow for fire provides a water treating device for attachment directly to a
<br /> protection.This means that the flow rate or velocities in the hydrant outlet. Tap water supply systems are flushed by
<br /> large mains during normal use are reduced significantly, opening fire hydrants and running potable water through the
<br /> allowing any particulates to settle to the bottom. After a 20 fire hydrants for a period of time. Since potable water
<br /> length of time the particulates would build up and if there is usually contains chlorine, it is necessary to remove the
<br /> any surges in the system the particulates are stirred up chlorine before the water enters rivers,streams and bays in
<br /> causing the water to appear dirty.To remedy this occurrence order to protect aquatic life.This is accomplished by passing
<br /> the entire system would have to be flushed annually from the water through a diffuser attached to the fire hydrant,
<br /> hydrants and blow-offs throughout the entire system. This 25 which diffuser contains a mesh bag with a sodium sulfite
<br /> method wastes millions of gallons of water each year,could tablet therein.This still wastes huge quantities of water and
<br /> possibly cause property damage,flooding the streets causing adds chemicals to water being discharged into the environ-
<br /> traffic problems and is usually performed at night to avoid rent.
<br /> the public eye, making the flushing procedure very costly. U.S. Pat. No. 6,170,514, issued Jan. 9, 2001 to
<br /> In addition to the above problems new regulations require 3o Esmailzadeh,shows a city water flushing and sludge pre-
<br /> that the water be dechlorinated before it is allowed to drain vention control apparatus for use with a city water system
<br /> into any storm drainage system and you will also be required having a plurality of street water mains interconnected by
<br /> to have a NPDES permit plus containment systems in place branch water mains and having hydrants connected to the
<br /> to protect against washing silt into the drains.Not to mention branch water mains, a city water flushing and sludge pre-
<br /> that you will need to shut down multiple valves to isolate the �s vention apparatus consisting of:a sludge-prevention control
<br /> section of main that you want to flush. valve insertable into a branch water main between two street
<br /> From time to time,it is necessary to flush water systems water mains and closer to one of the two street water mains;
<br /> which deliver potable tap water.This is especially the case the sludge-prevention control valve in the closed position
<br /> with newly lined fresh water mains which have been 40 preventing water from flowing through the branch water
<br /> repaired by lining interior surfaces of the mains with a resin main from the closer street water main during a flushing
<br /> material.Before water passing through a pipe which is used operation,whereby all water flows through the branch water
<br /> for drinking water purposes, it is necessary to thoroughly main from the more distant street water main and thereby
<br /> flush the mains with tap water. In order to maintain water flushes the portion of the branch water main between the
<br /> quality,it is also necessary,from time to time,to flush local sludge-prevention control valve and the more distant street
<br /> tap water delivery systems such as neighborhood and sub- as water main;and a control mechanism adapted to close and
<br /> division tap water systems. open the sludge-prevention control valve.Again,this system
<br /> Generally, discharges from potable water systems result dumps a tremendous amount of water and does not treat the
<br /> from overflow, flushing, disinfection, hydrostatic testing, water.
<br /> mechanical cleaning or dewatering of vessels or structures sa U.S. Pal. No. 5,911,255, issued Jun. 15, 1999 to Bond,
<br /> used to store or convey potable water. This frequently claims a pipe cleaning method and device utilizing a partial
<br /> includes fire hydrant flushing in which high velocity streams blockage object positioned in a water pipe for a method of
<br /> are generated on the order of 2,000 gallons per minute for a cleaning deposits from the inside of a pipe, comprising
<br /> period of 10-15 minutes. By periodically testing fire flushing a liquid through the pipe,and locally increasing the
<br /> hydrants,it can he determined if sufficient water is available 55 liquid flow rate adjacent the pipe wall due to the presence of
<br /> in the system for fire fighting purposes. the object.This system requires opening a hydrant to release
<br /> Potable tap water usually contains residual chlorine.The the water filled with particulates removed from the linings of
<br /> Federal Clean Water Act and state agency regulations the water mains.
<br /> regarding discharges of potable water, such as regulations U.S. Pat. No. 5,201,338, issued Apr. 13, 1993 to
<br /> promulgated by the Maryland Department of the se McKeague,describes a system and device for flushing water
<br /> Environment,require that total maximum daily amount of mains. A water distribution system includes flushing
<br /> residual chlorine must be less than 0.1 mg/liter. At levels hydrants having buried valve assemblies and a removable
<br /> higher than 0.1 mg/liter,aquatic life is endangered and fish top stock carried from valve assembly to valve assembly.A
<br /> kills occur. Since potable tap water and water discharged vertical marker replaces the top stock when the hydrant is
<br /> from fire hydrants which originates with county and munici- 65 not in use.The buried valve assembly includes a valve urged
<br /> pal water systems is necessarily initially chlorinated,heavy closed by water pressure and an actuator rod extending
<br /> discharges of this water will adversely affect aquatic life through a spider in the top of a vertical barrel.A lock nut on
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