Abstract: An improved metering dispenser system for delivering a fixed or variable measured quantity of a high viscosity material such as adhesives or sealants for application to a substrate is disclosed. It uses an Archimedian screw pump having a stator formed with a spiral cavity therethrough, and a spiral rotor which is driven by a variable speed drive motor. The stator has a nozzle attached to its outlet end, the inlet end thereof being in fluid communication with a reservoir for the material. The dispenser system is adapted for use in combination with a robotic system so that the nozzle is manipulated thereby. The rotational speed of the drive motor is controlled in response to a signal representative of a nozzle velocity so that the nozzle can apply a ribbon of the material with a fixed width to the substrate despite nozzle velocity variations. When the nozzle is about to come to a stop, the drive motor is rotated in a reverse direction so as to cause the nozzle to stop discharging the material instantly.

Abstract: This disclosure relates to a metering dispenser which dispenses fluid in accurate proportion to the pump revolution speed, and to an improved shaft seal for the motor drive shaft of a metering dispenser. An elastic sleeve membrane is mounted inside an expanded area provided in a part of the peripheral wall of the pump casing so that a constant-pressure chamber is formed to the outside of this sleeve membrane, and the pressure inside the pump casing is maintained within a set pressure range by introducing a pressurized fluid into this constant-pressure chamber and releasing the pressurizing fluid from the constan-pressure chamber as needed.