Method and device for applying fluids to substrates

#The present invention relates to a method of applying fluids to substrates, in which the flow of fluid is interrupted and released by movement of a valve body relative to a valve body seat.

#The present invention also relates to a device for applying fluid, especially hot melt adhesive, to a substrate which is movable relative to the device, having a supply channel that may be connected with a fluid source for supplying fluid, a nozzle system with an output opening for delivering the fluid that may be fed with fluid via the supply channel, and having a valve system for optionally interrupting the flow of fluid, which has a valve body that is movable relative to a valve body seat, that is movable back and forth between a position that interrupts the flow of fluid and a position that releases the flow of fluid.

#Methods of the forenamed type, and corresponding devices for executing them, are used in a large number of applications in which it is necessary to apply fluids. One large area of use is the application of adhesives, paints or enamels, oils or waxes when producing or preserving various products.

#Preferred embodiments of the device according to the present invention and of the method will be explained on the basis of the accompanying drawing. The figures show the following:

#FIG. 1: A device according to the related art for applying fluid (application head), in a cutaway depiction;

#FIG. 2: A cutaway view of a first embodiment of the device according to the present invention;

#The device depicted in FIG. 1 (also referred to below as the application head), displays characteristics of the preferred embodiments of the device according to the present invention. It is suited to the application of liquid or viscous fluids onto substrates, and comprises essentially a metallic basic structure 10, a nozzle system 20 screwed to basic structure 10, a valve system 30, and a controller 50 for actuating valve system 30. In basic structure 10 there is a fluid supply channel 40 which may be connected to a fluid source to supply fluid to nozzle system 20, ahead of which there is a filter 60.

#Valve system 30, connected into supply channel 40, has a valve body 32 which is movable together with a valve body sealing surface 31 from an open position to a closed position, which works together with a valve seat 33 formed on basic structure 10 in such a way that the flow of fluid into nozzle system 30 is interrupted in the closed position and is released in the open position. To accomplish this, valve body 32, which is linked to a piston which is movable in a cylinder within controller 50, is moved pneumatically in one direction or the other. The piston is actuated electro-pneumatically in the conventional way by a control device 70, using a solenoid valve. Valve body sealing surface 31 comes into contact with valve seat 33 by moving counter to the direction of flow of the fluid, in order to interrupt the fluid flow. It is located inside a valve chamber formed in the basic structure 10, which valve chamber is part of the supply channel 10 [Translator's note: so numbered in the German original; should be 40] and communicates with a fluid output channel formed in nozzle system 20.

#Nozzle system 20 is designed as a slit die and constructed in multiple parts, but other nozzles may be used as desired. It includes a mouth piece 22, a mouth piece holder and a nozzle piece 26. Nozzle system 20 is mounted on basic structure 10 with screws 25, which simultaneously connect nozzle piece 26 to mouth piece holder 21, while mouth piece 22 is detachably connected to mouth piece holder 21 with screws 27, a conventional spacer (shim plate) being placed between the two. Nozzle piece 26 and mouth piece holder 21 are sealed relative to each other by sealing elements.