Abstract: A method and apparatus for carrying out the deposition of a paste like and/or viscous material, such as solder paste, on a substrate through the apertures or openings of a stencil are provided for use, for example, in screen printing in the mounting of components on a printed circuit board. A hollow receptacle for the material is provided with a lower aperture which is orientated towards the stencil. The lower aperture of the receptacle is delimited defined such that its length is adjusted to the dimensions of the substrate and that its width is a function of the speed of execution of the screen printing. This delimitation is implemented by sealing members preferably comprising two wipers on respective sides of the aperture, transverse with respect to the direction of displacement of the receptacle, orientated one towards the other and inclined with respect to the horizontal between the wipers at an angle of between 120° and 180°.

Abstract: A method and apparatus for carrying out the deposition of a paste like and/or viscous material, such as solder paste, on a substrate through the apertures or openings of a stencil are provided for use, for example, in screen printing in the mounting of components on a printed circuit board. A hollow receptacle for the material is provided with a lower aperture which is orientated towards the stencil. The lower aperture of the receptacle is delimited defined such that its length is adjusted to the dimensions of the substrate and that its width is a function of the speed of execution of the screen printing. This delimitation is implemented by sealing members preferably comprising two wipers on respective sides of the aperture, transverse with respect to the direction of displacement of the receptacle, orientated one towards the other and inclined with respect to the horizontal between the wipers at an angle of between 120° and 180°.

Abstract: A measure window (29-30, FIG. 2d) is provided in a Doppler velocity profile (FIG. 2c) by deleting an initial section (T.sub.1) and a terminal section (T.sub.2) of each emission cycle of a train of ultrasound of a period T so as to conserve only the section (T.sub.o) which it is desirable to study. The conserved section (T.sub.o) is thereafter segmented into a certain number (N) of measure channels. The advantage of restricting the zone divided into channels to the part which is really useful is that the definition of the profile which is obtained is improved, even when the emitter-receptor of ultrasound is located at a relatively important distance in comparison with the depth of the zone which is studied.