|Low expansion foam|
Low-expansion foam generators operate with a pre–mix feed. The foam nozzle converts the supply pressure into speed with the air suction function which vigorously agitates to produce the foam sprayed from a distance.
The foam nozzles are available in two versions, a self-suction version of the emulsifier, which involves transporting the emulsifier can with the nozzle, and the nonself suction version where the premixing is carried out using a proportioner generally installed near the emulsifier supply.
These two options each have their advantages and disadvantages. For the non-self-priming version, the passage through the proportioner reduces the pressure by at least 35% and even 40% if the injector does not have a auto–regulating system. This reduced pressure limits the flow rate available for the nozzle. As for the auto–suction system, it requires to transport the emulsifier close to the foam nozzle and replace it regularly.
My first non-auto-suction foam lance used the principle of a resonance chamber between two diaphragms whose turbulences stirred the air at the outlet, generating a beautiful foam.
For the self-suction system, the system operated with a convergent providing a velocity of the jet looking like the pipe of an organ.
The output proven by this device exceeded everything on the market, until the day I lost a deal, I heared that my device was not beautiful.
At that moment, I understood that the physical characteristic was for some people less important than the aesthetics of the devices. I then reviewed the external presentation again so I would never miss a deal again. The goal was achieved at the expense of the cost of production.
At that time, at the end of the 1980s, POK® had no test facilities.
I used to go to industrial areas during lunchtime and use pressure and flow from the hydrants to improve the characteristics of the appliances.
Later on, when POK moved to Nogent-sur-Seine, we were able to implement more serious test methods with which our devices were able to refine their characteristics, allowing us to continue to surpass the copies of our devices by Asian manufacturers.
It should be noted that in some regions, even in Europe, the emulsifiers used for testing do not comply with European standards, therefore the test results may differ from those announced in our specifications. Our expertise in this field allows us to adjust the results according to the qualities of the emulsifiers, knowing that any change has a cost.