Patent ID: 8087544

Claim:
A method of mixing liquid components in a predetermined ratio, said method comprising the steps of: flowing a first liquid component through a first inlet to a mixing chamber; flowing a second liquid component through a second inlet to the mixing chamber for mixing of the first and second liquid components in the mixing chamber and exit of the mixture through an outlet from the mixing chamber; sensing the flow of the first liquid component through the first inlet; sensing the pressure of the flow of the first liquid component in the first inlet upstream from the mixing chamber; determining the sensed pressures of the first liquid component that exist for various sensed flows of the first liquid component when there is no flow of the second liquid component; determining the sensed pressures of the first liquid component that exist for various sensed flows of the first liquid component when there is a flow of the second liquid component that provides a predetermined ratio of flows of the first and second liquid components to the mixing chamber; wherein for any particular sensed flow of the first liquid component only and associated sensed pressure of the first liquid component when there is no flow of the second liquid component, a corresponding incremental increase in the sensed pressure of the first liquid component occurs in response to flow of the second liquid component when the flow of the second liquid component is such as to yield a predetermined ratio of the first and second liquid components being flowed into said mixing chamber, so that for any particular sensed flow of the first liquid component there is a target sensed pressure of the first liquid component that exists when the flow of the second liquid component is such that the predetermined ratio of the first and second liquid components is being flowed into said mixing chamber; and controlling at least one of said flowing steps, in response to said pressure and flow sensing steps during simultaneous flow of the first and second liquid components, to vary the flow of at least one of the first and second liquid components to flow the predetermined ratio of the first and second liquid components to the mixing chamber.