Abstract: In a method for assembling a needle valve having a housing, at least one valve needle longitudinally displaceably guided in the housing in a first spatial direction, and at least one valve seat plate, the plate for each needle has a valve seat associated with the needle, at which seat an outlet opening for a fluid can be closed and opened by back and forth movement of the relevant needle. In a first step the plate is fastened to the housing by a fastener such that it has limited movement with respect to the housing. In a second step each needle is set into a back and forth movement in which it is alternatingly placed onto and lifted up from the associated seat. In a third step the plate is fixed on the housing while the at least one needle moves back and forth.

Abstract: A metering valve has a closing member and a valve seat. The closing member is movable between a closed position on the valve seat sealing a material outlet, and an open position raised above the valve seat leaving the outlet clear. An actuating element rigidly connected to the closing member is arranged between first and second piezo-actuators at a distance from the first piezo-actuator in the closed position less than the maximum length change of the first piezo-actuator, or lies loosely thereon and at a distance from the second piezo-actuator longer than the maximum length change of the first piezo-actuator. The actuating element in the open position is arranged at a distance from the second piezo-actuator less than the maximum length change of the second piezo-actuator, or lies loosely thereon and at a distance from the first piezo-actuator greater than the maximum length change of the second piezo-actuator.

Abstract: A metering valve for viscous materials has a housing, a material channel extending in the housing and opening into material outlet openings, and a number of valve pins, which are movably mounted in the housing, the number corresponding to the number of material outlet openings, wherein a valve seat is associated with each valve pin and each valve pin is movable between a closed position, in which it sits on the valve seat associated with it and closes one of the material outlet openings, and an open position, in which the material outlet opening concerned is exposed. The valve pins are produced from carbide and are guided in a longitudinally displaceable manner through feed-through openings in a guide block arranged at a distance from the valve seats, wherein the guide block is produced from carbide, at least on the inner surfaces of the feed-through openings facing the valve pins.

Abstract: A metering valve has a closing member and a valve seat. The closing member is movable between a closed position on the valve seat sealing a material outlet, and an open position raised above the valve seat leaving the outlet clear. An actuating element rigidly connected to the closing member is arranged between first and second piezo-actuators at a distance from the first piezo-actuator in the closed position less than the maximum length change of the first piezo-actuator, or lies loosely thereon and at a distance from the second piezo-actuator longer than the maximum length change of the first piezo-actuator. The actuating element in the open position is arranged at a distance from the second piezo-actuator less than the maximum length change of the second piezo-actuator, or lies loosely thereon and at a distance from the first piezo-actuator greater than the maximum length change of the second piezo-actuator.

Abstract: An application nozzle for applying viscous material to a workpiece includes a nozzle body which has a material inlet opening and material outlet openings which are arranged in at least one row in a material outlet face. An inlet channel extends in the nozzle body from the material inlet opening to at least one branch point. At each branch point, two distributor channels extend in the nozzle body in opposite directions from the inlet channel, wherein the distributor channels are each arranged over their entire length at a distance from the material outlet face, and at least one outlet channel extends in the nozzle body from each of the distributor channels in each case to one of the material outlet openings.