Abstract: An apparatus for generating foam includes a power source such as an internal combustion engine mounted in a frame for portable transportation of the apparatus. The power source drives an air compressor through an electric clutch which can disconnect the air compressor and a water pump. The water pump generates flow of the water under pressure through a duct system either to a water discharge valve or to a foam discharge valve. The foam is generated by injecting into the water stream a surfactant which is injected by reciprocating valve arrangement operated by flow of the water. The flow is controlled by a maximum flow orifice, a minimum flow orifice and an adjustable valve. The air compressor supplies a surge tank and the air is passed from the surge tank through a pressure regulator to a mixing device where the water and surfactant is mixed with the air to generate the foam.

Abstract: A rotary switch valve, particularly for use in a vehicle where the operator may wish to face in either direction such as on a tractor where implements or attachments may be mounted on either the front or rear ends. The valve consists of at least two passageways for allowing passage of hydraulic fluid, which passageways pass through both a casing and a spool, relative rotational movement being allowed between them. Upon 180.degree. relative rotational movement, the passageways feed fluid from the outlet ports in a sense opposite to that when the spool and casing were in their original positions. The steering system of the vehicle, therefore, will continue to direct the vehicle in its normal sense.