Basic High Pressure Jetting Information
About Cleaning Conduits, Pipes, Sewers & Drains
Pipe cleaning is commonly performed by a technique known as sewer jetting. Sewer jetting is the application of streams
of high pressure water for use within pipes for cleaning & debris removal. Water at the correct high pressure can cut
roots, dissolve blockages, emulsify grease and soaps while spray washing pipe wall surfaces. As part of the jetting
process, the water from the nozzle can also wash away accumulated dirt or debris on the bottom of the pipe at the same
time.
For sewer jetting, a jetting nozzle is attached to the end of a length of high pressure hose with the other end
connected to a high pressure water pump. Jetting nozzles have small precision machined orifices or jets to restrict
water flow from the jetting pump thus causing high pressure to build within hose. As the pressurized water is
expelled from the nozzle jets it reverts from pressure to velocity (speed) creating thrust that allows the nozzle
to pull the jetting hose. With the system pressurized, high pressure jetting hose coiled on a hydraulic powered hose reel
(up to 500') is released by the operator who controls the travel speed and distance of the nozzle up the pipe.
Pressurized water expelled from the nozzle jets cleans debris, removes pipe blockages or roots from the inside
of the pipe while traveling through the pipe. Optimum cleaning is achieved when the hose is being rewound onto
the hydraulic reel. During this action, water from the nozzle jets effectively forms a curtain or wall of high
pressure water that forces (or rakes) the debris downstream. Sewer jetting technology can be applied to clean all
size pipe diameters with the appropriate size of high pressure jetting unit.
RPD 6 Rear Nozzle
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RPD 3 Rear, 1 Forward Nozzle
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US Jetting RPD nozzles depicting two basic nozzle styles used for conduit, pipe, sewer & drain cleaning
applications. Rear jets provide propulsion of nozzle while cleaning pipe wall surface. Forward jet is used to
penetrate blockages for nozzle to pass & through cleaning by rear jets.
RPD nozzles can be ordered for different pressures and water flow rates.
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The majority of pipes that need to be cleaned & maintained and / or potential applications for high pressure jetting units
are:
- Sanitary or Mainline Sewers: located under streets and roads that connect building laterals to a municipal wastewater
treatment plant for treatment. Wastewater flows freely through sewers via gravity. Sewers are connected at various
intervals by manholes (maintenance access point) that in some applications will allow for a change of direction of
wastewater flow. Municipal sewers can range in size from pipes as small as 6 inches, increasing in diameter as more
& more laterals connect to the system. Sewer blockages can form as a result of root infiltration, food grease buildup,
soap residue buildup, dirt and debris accumulation. Blockages can also occur from pipe failure or collapse that will
require excavation to correct. Private sanitary wastewater collection systems of similar construction can be found
on privately owned property connecting buildings in apartment and office complexes, universities or other large
campus-type facilities that ultimately discharge into a municipal wastewater systems.
- Laterals - Pipes that connect building drainage systems to municipal sewers, considered to be part of the property
and the responsibility of the property owner. Typically, laterals are 4" & 6" diameter pipes that connect directly
to municipal sewer pipelines, but can be larger for commercial or industrial buildings. Lateral blockages can form
as a result of root infiltration, food grease buildup, soap residue buildup, dirt and debris accumulation. Blockages
can also occur from pipe failure or collapse that will require excavation to correct.
- Drains - Drainage pipes are located under or within buildings, considered the be part of the property and the
responsibility of the property owner. Drains in buildings can range in sizes from 2" to 6" diameters (typically)
that normally contain "Tees" or "Elbows" for wastewater directional changes. Drain blockages can form as a result
of food grease buildup, soap residue buildup, dirt and debris accumulation.
- Storm Drains - pipes that are limited to the collections and control of rainwater. Rainwater can be collected and
directly diverted to streams or rivers without passing through a water treatment plant. Storm drain blockages can
form as a result of root infiltration, silt, dirt and debris accumulation. Blockages can also occur from pipe
failure or collapse that will require excavation to correct.
- Process Pipe & Conduits - Pipes of all diameters & lengths used in manufacturing plants, chemical plants & food
processing facilities that transports liquids other that sanitary wastewater or rainwater. Blockages in process
pipelines can be caused by many factors related to the process, each individual application occurrence will have
unique factors to be dealt with on a case by case basis.
Hard scale mineral buildups found inside of pipes will reduce overall pipe flow capacity. High pressure water at
the correct pressure can remove any scale buildup no matter how irregular without damage to the original pipe.
All of the above types of pipe systems are susceptible to blockages and thus inconvenient backups or potential
economic loss. Blockages can occur from the buildup of debris over a period of time, ingress of root infiltration
or from foreign debris introduced into the pipeline (accidentally or maliciously). No matter what type of debris
that is the cause of a blockage; high pressure jetting is the preferred method of re-establishing water flow.
High pressure jetting not only removes a blockage but washes away all debris found within a pipe. Using high
pressure water is faster and less physically labor intensive than use of a mechanical rodding or cable machine.
High pressure jetting units maintain constant working pressure and cleaning power at the nozzle end. Mechanical
machines will lose cutting and torque power as rod or cable distances increase within pipelines from the point
of entry.
High pressure jetting has another advantage over cable or rodding machines. Where access is difficult, a lightweight,
flexible jet hose is a safer and more practical solution. Pipelines that are suspended from ceilings or catwalks
are easily cleaned using a high pressure jetting hose rather than a heavy, cumbersome mechanical drain cleaning
machine. Cleaning vertical stacks or vents is easier with a high pressure jetting unit and lightweight jetting hose
than with heavy drain cleaning cables or rods.
Over the past 70 years sewer & drain lines have been installed with little or no attention paid to routine pipeline
maintenance. The "bury and forget" or "out of sight, out of mind" attitudes toward sewer lines has now led to a
growing maintenance and rehabilitation industry. With increased collection system integrity & environmental concerns,
inspection of wastewater collection systems has become a major market application for high pressure jetting units.
Pre-cleaning of sewer and drain pipelines with high pressure water prior to televised inspection (CCTV) surveys for
determination of pipeline structural integrity is now a recognized standard operating procedure. Cleaning and
CCTV inspection of laterals and pipes under buildings for structural defects is also growing in demand, especially
at the time of property transfers.
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US Jetting offers the Better Jetter training program for owners, operators, managers and technicians.
The Better Jetter course is designed to educate & train personnel that work with high pressure jetting units
to improve operational, maintenance and marketing skills. Better Jetter courses are conducted throughout the
country on a regular basis. For scheduling and registration information, please contact US Jetting or click on
Training in the left link box. |
Nozzles with all jets at rear and forward for cleaning
Nozzles with all jets at rear is typically used for cleaning pipes that are not clogged. All water power is directed
to pipe wall surface and provides maximum thrust for nozzle.
Nozzles with a forward firing jet should be used to remove pipe blockages to restore pipe flow. With flow restored,
change to an all rear jet - nozzle for more effective finish pipe cleaning.
illustrations above and below show how high pressure jetting can clean a pipe or remove a pipeline blockage.
The concept is the same for a 2, 4, 6" pipes or an 18" pipe. Periodic pipe cleaning is required to maintain
maximum flow capacity of a pipeline to reduce potential surcharging from accumulated grease or scale buildup.
US Jetting has consistently developed and improved the concept of High Pressure - Low Flow jetting theory with practical
end user results. Given a set engine horsepower, it is more efficient and better to develop higher water pressure at
a lower flow rate than to develop lower water pressure at a higher flow rate. The High Pressure - Low Flow jetting
concept has proven to have more applications and better cleaning effectiveness, enhancing the reputation of US Jetting.
To read more about High Pressure - Low Flow theory, click here Selecting A High Pressure Jetter
or within the link at left.
No matter what the physical size of the hight pressure jetting unit or the water capacity of the tank, it is the pressure
and water flow produced by the high pressure jetting pump that cleans the pipe.
US Jetting Nozzles
In addition to fixed type nozzles, US Jetting offers a full range of spinning, rotating, flail
and milling nozzles used for increased pipe cleaning efficiency or for unique pipe cleaning applications.
Contact US Jetting to inquire about the design & manufacture of a high pressure jetting unit to suit your specific application.
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