Abstract: A liquid filter device has a housing and a multiple of closely spaced discs provided in the housing, the discs having holes which are adapted to be in alignment so as to define at least one elongated passage. The discs have separating means separating the discs from each other so as to provide a flow gap between adjacent discs. A filter tube is provided in each elongated passage. A fluid inlet leads into the housing to provide fluid into the interior of at least one filter tube, and a fluid outlet leads from the housing to withdraw fluid, which has passed through the filter tubes and into the flow gap between the discs. Interconnection means interconnect the ends of the filter tubes, and a resin casting surrounds the interconnection means.

Abstract: A sequential blasting system includes a plurality of electrically fired detonators and a pyrotechnical activated switch associated with each detonator. On firing of a detonator, the associate pyrotechnical activated switch primes the sequentially next to be fired detonator. Alternate detonators are connected to first and second conductors, respectively, through an alternating sequencer, which sequencer alternatingly connects the first and second conductors with a source of electrical power to fire the detonator primed by the previously actuated pyrotechnical activated switch.