Anyone know how to make a soap foam nozzle?

Question

I've used those hand soaps that have close to a 5:1 ratio of water to soap in them and when you press down on the top, they produce a soap foam. I'd like to make a nozzle that does this on a larger scale. I've seen ones for pressure washers that aspirate the soap into the nozzle, but I want one that works just like the hand soap one. I want to just have to force the premixed diluted soap mixture into the nozzle and have foam come out at a velocity proportional to the input pressure.

Does anyone know how something like that would be designed?

Thanks in advance for any info.

Ecnerwal · Accepted Answer

I'm guessing the soap dispenser is a two cylinder pump - one pumps soap solution, the other pumps air. Perhaps the firefighters among us can provide details on foam nozzles - I assume those suck air in by venturi action. I used to use a film washer that did the same thing to inject bubbles in the column using the force of the incoming water, and it would foam very nicely if one dropped a drop of photo-flo in the intake.

Bugs · Answer

Go to your local fire dept. and ask to look at their foam generator, ifthey have one. That should give you a good idea. It's just a venturiand aspirator that sucks up the foam/soap solution and blents it withwater and air to make foam.Bugs

Roger & Lorraine Martin · Answer

Years ago (maybe 20) I had a foam lance attachment for a high pressure washer, the venturi was on the suction side of the pump to get the soap into the mix before the lance. The lance had a section about 150mm long partly filled (90%) with small nylon balls of varying sizes. The tube probably trebled in diameter at the same time so dropped the pressure and the mix came out of a fairly large nozzle.

This flocked up the detergent mix and it really hung onto the vehicles we were cleaning.

Anyone know how to make a soap foam nozzle?

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