Abstract: A security thread for use in a paper-based value document, such as currency or banknote paper, includes a plastic substrate coated with one or more regions of "soft" magnetic material. A device for verifying both the authenticity and the denomination of the document includes a coil that is driven by an alternating current to thereby provide a uniform magnetic field within a predetermined spatial region. As the document passes in proximity to the drive coil, the applied magnetic field saturates the regions of magnetic material on the security thread. The magnetic regions provide a response magnetic field that, because of the saturation of the magnetic regions, is a non-linear response containing a multiple of frequency components, including a component at the fundamental or drive frequency and various harmonic frequency components. A receive coil senses the response magnetic field.

Abstract: A visually verifiable and machine-readable security thread having at least two security detection means located thereon, where a first security detection means comprises a machine-readable repeating pattern and where a second security detection means comprises visually verifiable metal-formed indicia. Such security threads are suitable for use with security documents, such as banknotes and the like, labels and any other documents or means of identification used for purposes which make the verification of the authenticity of each specimen desirable at least once in its lifetime.

Abstract: Filtration apparatus in which the filter medium is in the form of filter material assembled with a carrier web which is caused to traverse through a filter chamber in a zig zag path. The material and carrier web assembly spans between the side walls of the filter chamber and is advanced by turning rolls disposed at upper and lower levels. The carrier web for the filter material extends between flanges projecting from the side walls of the filter chamber and auxiliary support for the carrier web is provided by a foraminous shelf extending between the flanges between the turning rolls and imperforate shelf portions in advance of the first turning rolls and following the last turning roll. Support girders underlie the foraminous shelf to limit deflection of the filter medium. The filter medium is disposed so that its edges overlie the sealing flanges, thereby preventing flow of liquid medium around the edges of the filter medium.

Abstract: Filtration apparatus in which the filter medium is in the form of a mat assembled with a support grid which is caused to traverse through a filter chamber in a zig zag path. The mat and support grid extend between the side walls of the filter chamber and are advanced by turning rolls disposed at upper and lower levels. The support grid for the filter mat extends between sealing flanges projecting from the side walls of the filter chamber and auxiliary support for the support grid may be provided by employing a foraminous shelf extending between the flanges. The filter medium is disposed so that its edges overlie the sealing flanges, thereby preventing flow of gaseous medium around the edges of the filter mat. Sealing engagement between the sealing flanges and the filter mat is assured by the inclusion of a series of apertures spaced along the length of the flanges.