The foam mixer works on the principle of an injector in which the shapes of the confusor and diffusor create low pressure in the suction chamber, causing the foam-generating substance to be siphoned through the suction hose.
The foam-generating substance is then mixed with water. A 1 to 6 % mixture can be set with the regulator. The mixer experiences an energy loss of 25 to 30 %. A minimum pressure of 0.2 MPa is required inthe branch for normal mixing.