Abstract: An apparatus for conveying paints is connectible via a supply passage to a reservoir and is connectible via a feed passage to an application device. The apparatus includes a diaphragm pump mounted in a closed housing and provided with an admission valve and a discharge valve. The diaphragm pump is driveable with an electric motor that can be switched by a manometric switch dependent on conveying pressure. The admission valve and the discharge valve are commonly arranged in a pump head and are held by a supporting element that is detachably connected to the pump head. Further, the discharge valve is located upsteam of a pressurized chamber that is connected to the feed passage and is also located in the pump head. Variations in feed passage pressure cause variations in the volume of the pressurized chamber by flexing a control diaphragm. The control diaphragm acts on an adjustment element to actuate a control switch. The invention provides an apparatus that is compact, reliable, and easy to manufacture.

Abstract: An electrically operated device such as a duplicating machine has a recptacle for accommodating a fluid for the chemical treatment of sheet material and like objects. The receptacle may be in the form of a dip tank designed for passing sheet material therethrough. This dip tank is connected via a supply conduit to a storage tank and the supply conduit includes a pump controlled by an automatic charging and metering unit for supplying fluid to the dip tank. A drain conduit leading to the storage tank is connected to the dip tank. This drain conduit includes a solenoid valve for stopping or allowing the flow of fluid through the drain conduit.