Proper Nozzle Selection In Sewer Cleaning

By NASSCO member Barry Howell, General Manager, Visu-Sewer, Inc. | August 2010 Vol. 65 No. 8

Jetter Equipment Being Used – The type of equipment will dictate the appropriate nozzle size. Nozzles correspond to hose size, i.e. one inch nozzles fit one inch hose, and so on. Knowing the pump capacity and pressure is critical to choosing the appropriate nozzle for the project and determines what size nozzle to use. For example, you would not use an 80 GPM one inch nozzle for a 15 GPM, one half-inch jetter.

Job Requirements – Nozzles are made to penetrate blockages, do maintenance cleaning, cut roots, remove grease deposits, etc. Manufacturers offer different features on different tools for a reason. Remember the carpenter? The jetter operator should remember that the condition of the pipe dictate the correct tool to be used. Penetrating nozzles are not intended to be grease removal tools, nor are root saws intended to be all purpose cleaning “heads”.

Angles of Incidence – Finally, when selecting a nozzle, the operator should understand the angles of the nozzle’s jets and how they affect the tool’s ability to do the work required. The technical term for this is “angles of incidence”. What these angles determine are either the nozzle’s ability to produce thrust (propel itself up the pipeline) or wall force (cleaning ability). As with most things in life, everything is a trade off. The wider the angle of a jet, the more wall force is produced at the expense of thrust; conversely, narrow jet angles propel the nozzle at the expense of cleaning ability. Nozzles may be referred to as a “40 degree” nozzle, and, for example, this should tell the operator that this tool will be an effective cleaner but generally have limited ability to propel itself. On the other hand, a nozzle featuring “8 degree” jets may run up the pipe like a rocket, but provide very little wall force for cleaning purposes.

In conclusion, nozzle selection is not difficult if the user understands the basics: how much can I spend, what is the job to be done, and what features are available.

For more information, please visit NASSCO’s website at www.nassco.org.

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