Two stage foam pump and method of producing foam

A method of generating foam comprising:

• delivering a liquid and a first volume of air through a first foam generator to generate a first foam;
• and
• delivering the first foam and a second volume of air through a second foam generator to generate a second foam;
• and
• regulating a flow of a fluid through the first foam generator using a high pressure valve;
• wherein the high pressure valve prevents the fluid from flowing past the high pressure valve unless the fluid is at or above a threshold pressure;
• wherein the liquid and the first volume of air are delivered through the first foam generator by a pump mechanism;
• wherein the liquid and the first volume of air are pressurized up to at least the threshold pressure when the pump mechanism is activated;
• and
• wherein at least one of the liquid and the first volume of air are received by a variable volume high pressure compartment;
• the method further comprising:
• reducing a volume of the variable volume pressure compartment from a first volume to a smaller second volume on activation of the pump mechanism, thereby increasing a pressure within the variable volume high pressure compartment up to at least the threshold pressure.