Method and apparatus for fluid mixing and dispensing

A fluid mixing device, comprising:

• an inlet passageway for connection to a primary fluid supply;
• an outlet passageway;
• at least two separate venturi passageways each connected between the inlet and outlet passageways, each venturi passageway having a reduced diameter throat portion, a first venturi inlet connected to the throat portion of a first venturi passageway and a second venturi inlet connected to the throat portion of a second venturi passageway, whereby fluids are drawn into primary fluid streams flowing separately in the first and second venturi passageways;
• the outlet passageway being spaced a predetermined distance downstream of the venturi inlets to prevent substantial backflow of one of the secondary fluids from one venturi passageway to the other passageway prior to mixing together of the two streams in the outlet passageway;
• at least the inlet passageway and venturi passageways comprising a single venturi tube and a septum extending along at least part of the length of the tube and dividing the tube into at least two venturi passageways;
• and
• the venturi tube having an inlet end and an outlet end, the septum terminating short of the inlet end, and the inlet passageway extending from the inlet end to the septum, the inlet passageway including an inwardly tapering inlet portion extending up to the throat portion.

A fluid mixing apparatus, comprising:

• a first inlet tube for connection to a primary fluid supply;
• a second inlet for connection to a first secondary fluid supply;
• a third inlet for connection to a second secondary fluid supply;
• an outlet tube;
• a venturi device having a first, inlet end connected to the inlet tube and a second, outlet end connected to the outlet tube;
• the venturi device comprising at least two separate venturi passageways each connected between the inlet and outlet ends of the venturi device, each venturi passageway having a throat portion, a first venturi inlet connected to the throat portion of the first venturi passageway and a second venturi inlet connected to the throat portion of the second venturi passageway, whereby secondary fluids are drawn into the primary fluid flowing separately in the first and second venturi passageways;
• the second inlet being connected to the first venturi inlet, and the third inlet being connected to the second venturi inlet;
• the outlet end of the venturi device being spaced a predetermined distance downstream of the venturi inlets to prevent substantial backflow of a secondary fluid from one venturi passageway to the other prior to mixing together of the two streams in the outlet passageway;
• and
• each venturi passageway being of substantially D-shaped cross-section.

A fluid mixing apparatus, comprising:

• a first inlet tube for connection to a primary fluid supply;
• a second inlet for connection to a first secondary fluid supply;
• a third inlet for connection to a second secondary fluid supply;
• an outlet tube;
• a venturi device having a first, inlet end connected to the inlet tube and a second, outlet end connected to the outlet tube;
• the venturi device comprising at least two separate venturi passageways each connected between the inlet and outlet ends of the venturi device, each venturi passageway having a throat portion, a first venturi inlet connected to the throat portion of the first venturi passageway and a second venturi inlet connected to the throat portion of the second venturi passageway, whereby secondary fluids are drawn into the primary fluid flowing separately in the first and second venturi passageways;
• the second inlet being connected to the first venturi inlet, and the third inlet being connected to the second venturi inlet;
• the outlet end of the venturi device being spaced a predetermined distance downstream of the venturi inlets to prevent substantial backflow of a secondary fluid from one venturi passageway to the other prior to mixing together of the two streams in the outlet passageway;
• and
• a plurality of separate third inlets for selective connection to said second venturi inlet, and a valve for controlling connection of any selected one of said third inlets to said second venturi inlet.

A fluid mixing apparatus, comprising:

• a first inlet tube for connection to a primary fluid supply;
• a second inlet for connection to a first secondary fluid supply;
• a third inlet for connection to a second secondary fluid supply;
• an outlet tube;
• a venturi device having a first, inlet end connected to the inlet tube and a second, outlet end connected to the outlet tube;
• the venturi device comprising at least two separate venturi passageways each connected between the inlet and outlet ends of the venturi device, each venturi passageway having a throat portion, a first venturi inlet connected to the throat portion of the first venturi passageway and a second venturi inlet connected to the throat portion of the second venturi passageway, whereby secondary fluids are drawn into the primary fluid flowing separately in the first and second venturi passageways;
• the second inlet being connected to the first venturi inlet, and the third inlet being connected to the second venturi inlet;
• the outlet end of the venturi device being spaced a predetermined distance downstream of the venturi inlets to prevent substantial backflow of a secondary fluid from one venturi passageway to the other prior to mixing together of the two streams in the outlet passageway;
• three separate third inlets for selective connection to said second venturi inlet, and a valve for controlling connection of any selected one of said third inlets to said second venturi inlet;
• the third inlets being connected to supplies of different secondary fluids, and the valve comprising a three-way valve;
• and
• a needle valve for controlling the amount of each secondary fluid supplied to said second venturi inlet.

A method of producing an output mixture of fluids, comprising the steps of:

• connecting a first end of an inlet passageway to a source of a primary pressurized fluid;
• connecting a second end of the inlet passageway to a single venturi tube divided into separate first and second venturi passageways by a septum extending along at least part of the tube and forming at least one planar wall of each venturi passageway, each venturi passageway having a venturi inlet and an outlet end spaced a predetermined distance from the venturi inlet;
• connecting the first venturi inlet in the first venturi passageway to a first secondary fluid supply, whereby a first secondary fluid is drawn into and mixed with the primary fluid flowing along the first venturi passageway;
• connecting the second venturi inlet in the second venturi passageway to a second secondary fluid supply so that a second secondary fluid is drawn into and mixed with the primary fluid flowing along the second venturi passageway, the first secondary fluid having a lower viscosity than the second secondary fluid;
• connecting the outlet ends of the separate venturi passageways to a single outlet passageway whereby the primary and first secondary fluid mixture is mixed with the primary and second secondary fluid mixture to produce an output mixture;
• and
• whereby the predetermined distance from each venturi inlet to the outlet passageway is such that substantially no backflow of the first secondary fluid mixture into the second venturi passageway is produced.

A fluid mixing device for mixing together at least three different fluids, comprising:

• a single venturi tube having a first, inlet end for connection to a supply of a first fluid and a second, outlet end;
• the venturi tube having a venturi throat portion of reduced diameter spaced between said ends;
• a dividing wall separating at least part of said venturi tube extending across said throat portion into at least two separate first and second venturi passageways of non-circular cross-section, the dividing wall having at least two opposing planar surfaces forming flat wall portions of said venturi passageways;
• and
• each venturi passageway having an inlet for connection to a supply of a second and third fluid, respectively, for mixing with the first fluid,
• whereby the second fluid is drawn into the supply of first fluid flowing in the first venturi passageway and the third fluid is drawn into the supply of first fluid flowing in the second venturi passageway, and the first and second fluid mixture is mixed with the first and third fluid mixture at the end of the dividing wall.