초록 ▼

A conductive liquid is dosed with a vessel having an upper rim and with a dip tube having a lower end projecting down into the vessel below the rim thereof. The vessel is periodically overfilled with the liquid such that periodically the liquid overflows the rim. Immediately after each overfilling o

A conductive liquid is dosed with a vessel having an upper rim and with a dip tube having a lower end projecting down into the vessel below the rim thereof. The vessel is periodically overfilled with the liquid such that periodically the liquid overflows the rim. Immediately after each overfilling of the vessel, the liquid is aspirated from the vessel through the dip tube until the lower end of the dip tube is above the surface of the liquid in the vessel. The resistance between the dip tube and the liquid in the vessel is continuously monitored and an error signal is generated either when the detected resistance falls below a predetermined threshold corresponding generally to that of the liquid after the overfilling but before the aspirating or when the detected resistance is substantially above the threshold after the aspirating and before the next overfilling. The flow of liquid out of the vessel is impeded except over the rim and through the dip tube at least during the aspirating step.

대표청구항 ▼

An apparatus for dosing a conductive liquid from a supply of the liquid to a user, the apparatus comprising; a housing; at least one vessel supported in said housing and having an upper rim; a dip tube supported in said housing and normally fixed relative to the vessel and having a lower end project

An apparatus for dosing a conductive liquid from a supply of the liquid to a user, the apparatus comprising; a housing; at least one vessel supported in said housing and having an upper rim; a dip tube supported in said housing and normally fixed relative to the vessel and having a lower end projecting downward with clearance into the vessel below the rim thereof; pump means for periodically supplying enough of the liquid from the supply to the vessel to cause the liquid to fill the vessel and overflow the rim thereof and for collecting the overflow below the rim; intake means adapted to be connected to the user and associated with said dip tube for periodically aspirating the liquid through the dip tube in the vessel above the lower end of the dip tube and feeding it to the user; control means connected to the pump means and intake means to operate the same alternately with the intake means only aspirating when the pump means is not supplying and the pump means only supplying when the intake means is not aspirating; a riser tube centered in said housing and connecting said pump means to said vessel; and said housing includes a reservoir at least generally coaxially surrounding the riser tube for receiving said overflow to be collected by said pump means.