42 TECHNICAL
Tube and drain cleaning nozzles – what you need to know
By
Hawk Pumps
Hawk Pumps , manufacturers , and distributors of a range of quality highpressure pumps , shares insight into tube and drain cleaning nozzles for highpressure pumps .
Pipe cleaning machines have various requirements to function at their best . Here are a few key points that should always be remembered :
• Boiler and heat exchanger tubes generally get a layer of various types of scale that restrict water flow and reduce heat transfer . Both will lower the flow and increase the amount of fuel needed to overcome the insulating effect of the scale .
• Slurry transfer pipes in various industries tend to become restricted by solids deposited on the internal walls of the pipes .
• Drainpipes in industry , hotels , hospitals , and garages suffer from deposits of grease and other sticky materials , especially from kitchen waste .
• Sewers are notorious for clogging ; usually from foreign objects being flushed into the system .
• Rainwater drainpipes and storm water drains tend to have litter and sand settling in the bottom of the pipes , eventually blocking them completely , causing flooding during rainstorms .
Pipe cleaning machines all have one thing in common : they need special nozzles designed for each specific application . High pressure pump machines are available or can be custom designed . But the choice of the correct nozzle , water flow , and pressure is very important .
The various types of nozzles have a few things in common . Most have jets facing backwards , which serve two main purposes ; to pull the hose into the pipe and to clean the pipe ’ s walls .
For cleaning walls , the jets tend to face backwards and outwards at a large angle . Sometimes , a forward-facing jet is not necessary , which allows larger , rear facing jets to be fitted .
All images : Hawk Pumps
Flounder nozzle for drain and sewer ( sand ).
Flounder nozzle for drain and sewer ( sand ).
If the problem is a blockage , a forward-facing jet is important , because the rear facing ones do not spray outwards as much , making it harder for the forward pulling power to overcome the negative effect of the forward jet .
• Boiler tube nozzles usually require relatively low volumes at higher pressures to cut through the scale , which can be extremely hard . They do not depend much on rear jets and do not have front ones , but rather have side jets on a spinning body . Occasionally , when the tube is all but blocked , a chisel nozzle with sharp hardened facets in front is needed to physically break the scale with forward facing jets . These nozzles are fitted to rigid pipes , rather than flexible hoses . The pumps needed here have low volumes ( about 20 l / min ) at 500 bar pressure .
• Slurry transfer pipes require simple ‘ bomb ’ shaped nozzles with rear facing jets . Here , depending on the pipe diameter , the pumps are of a medium ( typically 80 l / min ) flow at about 150 to 200 bars . Occasionally , a nozzle with spinning chains will be needed to improve the cleaning effect .
• Drainpipes also usually are cleaned using ‘ bomb ’ nozzles and require pumps like the slurry pipe applications . If the pipe is blocked , a nozzle with a front jet is called for . Hard blockages need cutter nozzles .
www . plumbingafrica . co . za @ plumbingonline @ plumbingonline @ PlumbingAfricaOnline July 2021 Volume 27 I Number 5