Abstract: An apparatus that prevents an undesirable chemical reaction between different liquid chemical streams in a dispenser comprising a dispenser having a common manifold leading to a use locus. The common manifold has a pumping station directed to the common manifold and the pumping station has at least two chemical input lines. The dispenser is controlled by an electromechanical controller that prevents pumping two liquid chemical streams in sequence without an intervening water flush and prevents pumping two liquid chemical streams simultaneously. The liquid inputs to the pumping station are keyed such that the inputs can be connected only to containers that fit the keyed inputs.

Abstract: Disclosed is a geometric lockout coupler assembly comprising a probe capable of reversibly moving between an open position and a closed position, the open position permitting fluid to pass through the probe; and a bung cup sized and configured to accept the probe. The probe further comprises a geometric configuration which cooperates with the complementarily shaped bung cup to allow fluid to flow through the probe while not permitting other probes to cooperate with the bung cup.

Abstract: Many water based agriculture chemicals such as dairy chemicals, including teat washes and teat dips, are supplied in concentrated form in containers or bottles. The concentrated liquid is typically diluted with water at a ratio of about 1 to 5 ounces concentrate per gallon of water to form a treatment solution. The present invention involves a device that can both meter and dispense a precise amount of concentrate from a storage container for dilution purposes. The device of the present invention includes a dispenser that is connected to a container of liquid concentrate, typically a plastic bottle containing 1 to 3 gallons of the concentrate liquid, that is held by a retainer. A precise amount of liquid is obtained by rotating a handle of the dispenser from a first position to a second position, preferably about 180.degree. to 360.degree..