A set of foam concrete machine includes three parts, a mixer, a foam generator and a pump. One of the most important ingredient required to produce foamed concrete is the aqueous stable foam.
The foam generator acts as a medium which transforms the liquid chemical into stable foam. Foam generators come in many sizes depending on the ability to hold and transform liquid chemical into foam.
As an example, one would need about 500 liters of foam to make 1cubic meter of foamed concrete @ about 1100 kg/m3 density.
In order to make 500 liters foam , one has to dilute say 1 liter of chemical foaming agent in 39 liters of water and subsequently transform this 40 liters of premix solution into 500 liters of foam using the generator.
As you can see, the expansion rate is 12.5 times (500/40). We can increase this expansion rate by introducing more air but this will degrade the quality of the foam. Therefore the capacity of a foam generator will depend very much on its ability to hold and pump out maximum amount of foam.
The typical foam generator runs from an air compressor and consists of a holding (filler) tank, foaming unit and a lance unit. The purpose of the holding tank is to hold the diluted foaming agent and subsequently deliver it through a foaming unit and lance. It is normally in the form of a pressurized tank and needs to be closed tight for operation. The volume of foam obtained from such a system depends very much on the size of these tanks. For large volumes it is impractical to use the tank system since it is bulky to carry about. Large capacity holding tanks are heavy and cumbersome for smaller scale on site production. They are also attached to the foaming unit and lance in such a way that it would be virtually impossible to detach it for future modification.