Dispenser for flowable materials

Abstract

A dispenser for dispensing flowable materials and in particular anaerobic materials. This dispenser has a material inlet which allows the flowable material to flow into a pump cylinder, and a material passage through which the flowable material exits the pump cylinder. The material is positively displaced from the pump cylinder by a material displacement assembly of the ball-nut follower-type. A flexible plastic diaphragm which has sufficient porosity to permit oxygen to flow therethrough is biased toward a closed position by a pressurized air supply which applies pressurized air against an outside surface of the diaphragm, enabling the diaphragm to function as a one-way shut-off valve. The diaphragm extends across the material passage formed in the pump cylinder and a material outlet through which the material exits the dispenser. The diaphragm is movable between an open position which allows the material to flow through the material outlet and a closed position which prevents material from exiting the pump chamber. The dispenser is relatively free of metal components which can create metal ions that may contact the material, and is free of dead spots within the dispenser, both of which can cause instant curing of the anaerobic material. In a second embodiment the dispenser includes two pump cylinders, with at least one cylinder including the diaphragm check valve, for dispensing two separate materials, one of which contains an anaerobic material into a motionless mixer mounted on the material outlet end of the dispenser.