Abstract: A cable system for carrying out seismic operations, comprising a multi-conductor cable built with multiple segments, each segment terminated with identical connector plugs. Each segment having a selected number P of take-outs for accepting P seismic signals. The group of P seismic signals from the take-outs are multiplexed in each cable segment, and travel over a single conductor pair in the successive segments to the recording truck, where they are demultiplexed, and as reconstituted signals, are processed and recorded.

Abstract: An improved hermaphroditic multiple connector plug having a front or mating end, and a back or cable end, comprising a cylindrical body having a contact assembly, including means to support a plurality of electrical contacts. The contact assembly surrounds and is sealed to the body, and has projections adapted to mesh with the corresponding projections on the contact assembly of a mating plug, so as to relatively index the two plugs and their contacts. The plug has a cylindrical tubular locking ring with diametrically disposed extensions which mesh with the extensions of the locking ring on a mating plug. There are sloping grooves and ridges on the projections so that as the locking ring is rotated clockwise with respect to a locking ring on a mating plug, the two plugs will be pulled and locked together. When the locking rings are turned counterclockwise with respect to each other, cam surfaces on the ends of the projections act to unlock and separate the two plugs.

Abstract: An improved butterfly valve with self energizing seal, having a body with parallel faces and a substantially circular opening therethrough, and a shaft transverse to said opening. A closure disc is rigidly attached to said shaft and spaced from said shaft a selected distance, with its plane parallel to a plane through the axis of said shaft. A seal ring, comprising a thin cylindrical metal ring with an elastomeric ring bonded to the inside surface thereof, is inserted into the upstream face of said body. The elastomeric ring has an internal seating surface which is a truncated conical surface, tapering upstream, and which is tangent to a spherical surface centered at the intersection of the axes of said opening and said shaft. The edge of the closure disc is in the form of a ridge, having a peak which is circular in crosssection. When the valve is closed, by rotating the shaft, the disc is in the plane of the seating surface and the ridge has a small radial penetration into the elastomeric surface.

Abstract: A cable charger for generating a timed series of pulses of high d.c. voltage, comprising a battery, inverter, and rectifier means to produce a high voltage d.c., means responsive to a first timing means to connect said battery to said inverter at periodic intervals and means responsive to a second timing means to disconnect said inverter from said battery at a selected time interval after the connection of said inverter to said battery. An alternate embodiment includes means responsive to the voltage output of the rectifier means for disconnecting the inverter from the battery when the voltage output reaches a selected value E. The connecting means between the battery and the inverter can be relay means or solid state switching means.

Abstract: An improved check valve having a housing or body with parallel faces and a substantially circular opening therethrough, and a shaft transverse to the opening. A flapper disc is rigidly attached to the shaft. A seat means comprising a metal ring is inserted into the upstream face of the body, and has a seating surface which is a truncated conical surface, tapering upstream. The conical surface is tangent to a sphere centered in said body. The disc, when closed, is in the plane of the seating surface. The edge of the plate is in close spacing to the seating surface, and is correspondingly tapered. The edge of the plate has a rectangular groove having a cylindrical base and walls perpendicular to the base. An O-ring is seated in the groove, and provides a self energizing seal. Means are provided to center the disc in the seat. Means are provided to apply a selected torque to the shaft.