THE PROBLEM

A leading UK water company contacted SNP about an issue at one of its wastewater treatment works.
Final effluent water running through a chamber 2.4m wide, where a flowmeter level transducer was placed, was producing a considerable amount of foam.

The foam meant that the transducer was giving false readings.
The client wanted a nozzle which could produce a spray to knock back the foam without overspraying the walls.

The solution needed to work, at least temporarily, with the existing pump and discharge pipework. Available was a pump delivering 120 l/min at 2 bar pressure.

CHALLENGES

• An anti-clogging solution was needed because the fluid being pumped through the nozzle would be final effluent, so would have a small volume of solids in it.
• The solution needed to work, at least temporarily, with the existing pump that took a feed from the chamber and sent water off to be sampled for ammonia.
• An optimal flow rate was needed to cover the width of the chamber without overspraying.

Before: High foam level (and proposed spray pattern)

After: Foam almost entirely suppressed

THE SOLUTION

Successful foam suppression requires a balancing act between having a sufficiently fine spray to give a large number of bubble-bursting droplets whilst keeping the droplet size large enough (run at low pressure) to actually burst the bubbles.

Furthermore, foam bubbles will often vary significantly in size and hence the droplet size required to burst the bubbles will also vary. As such, a spray with a broad spectrum of droplet sizes is more effective than one with a narrow droplet size spectrum.

What was needed was a nozzle which could produce a solid cone pattern at the base of the chamber to disperse the foam without overspraying the walls. SNP recommended the MaxiPass nozzle in 316 stainless steel suspended over the foam to deliver even coverage across the whole area.

Model: MP437W
Connection: 1" BSP
Material: 316 SS
Pressure: 1 bar
Flow Rate: 68.4 l/min

THE PRODUCT – MaxiPass®

The MaxiPass is the ultimate clog-resistant nozzle with the largest free passage available in a full cone nozzle.

DESIGN FEATURES

• Two unique S-shaped internal vanes allow free passage of particles
• High energy efficiency
• Easily handles dirty, lumpy liquids
• Male and female connections
• Flanged connection available
• Patented design

SPRAY CHARACTERISTICS

• High reliability spray performance under even the most difficult conditions
• Spray pattern: Full Cone
• Spray angles: 30°, 60°, 90° and 120°
• Flow rates: 2.60 to 3540 L/min