A thyristor protected against breakover firing is disclosed which has a region which, in comparison to the remaining semiconductor body, has a lower breakdown voltage. This region is provided with an auxiliary electrode and is separated from the remaining semiconductor body by a trench. Upon onset of the avalanche breakdown in the blocking direction, a voltage greater by 0.5 V, compared to the first emitter electrode, can build up at the auxiliary electrode without the thyristor firing. The auxi...

The present invention provides a process for the surface treatment of antimony oxide for use as a pigment in paints or plastics wherein a hydrous oxide or mixture of oxides is precipitated onto the antimony oxide pigment. Specifically, this invention concerns the precipitation of hydrous oxides of titania, alumina or silica. In operation, the pH of an aqueous slurry of antimony oxide is adjusted to be within a specified pH range and the coating of the antimony oxide is effected by adding an amou...

Method of determining the permeability of an underground medium from NMR logs of the permeability of rock fragments from the medium, based on prior calibration of the permeability resulting from this measurements, from direct measurement on rock fragments, such as cuttings for example. The method mainly comprises measuring permeability (k) from rock fragments, measuring the signal produced by a device allowing NMR analysis of the rock fragments previously saturated with a protonated liquid (brin...

A vertical shock responsive fluid valve assembly capable of automatically closing a fluid valve in response to earthquake forces or other shock forces of a predetermined magnitude. The vertical shock responsive valve assembly has a flow control mechanism having a cradle that holds a movable ball in a recess at a point perpendicular in relation to a horizontal base plate, where the ball can be rotated 360.degree. in any direction during seismic actions or other shock forces and rolls out of its r...

This invention relates to a cycling-type continual quick service valve device which embodies therein a quick service valve means that comprises two valves each operatively connected to an abutment subject to fluid under pressure supplied from a train brake pipe through a first restriction to a chamber on one side thereof and subject to fluid under pressure supplied from the brake pipe to a chamber at the opposite side and to a quick service chamber via two restrictions arranged in parallel and i...

A vertical shock responsive fluid valve assembly capable of automatically closing a fluid valve in response to earthquake forces or other shock forces of a predetermined magnitude. The vertical shock responsive valve assembly has a flow control mechanism having a cradle that holds a movable ball in a recess at a point perpendicular in relation to a horizontal base plate, where the ball can be rotated 360.degree. in any direction during seismic actions or other shock forces and rolls out of its r...

A vertical shock responsive fluid valve assembly capable of automatically closing a fluid valve in response to earthquake forces or other shock forces of a predetermined magnitude. The vertical shock responsive valve assembly has a flow control mechanism having a cradle that holds a movable ball in a recess at a point perpendicular in relation to a horizontal base plate, where the ball can be rotated 360.degree. in any direction during seismic actions or other shock forces and rolls out of its r...

The timing mechanism illustrated in U.S. Pat. Nos. 3,727,015, 3,805,005 and 4,406,932 have been improved by providing cooperating housings for the timing mechanism elements and the motor drive for the timing mechanism such that there is no external wiring between the motor housing and the timing mechanism elements. Means are provided in the motor housing to properly locate the motor and insure proper location between the motor, its associated gear train, and the elements of the timing mechanism.

A vertical shock responsive fluid valve assembly capable of automatically closing a fluid valve in response to earthquake forces or other shock forces of a predetermined magnitude. The vertical shock responsive valve assembly has a flow control mechanism having a cradle that holds a movable ball in a recess at a point perpendicular in relation to a horizontal base plate, where the ball can be rotated 360.degree. in any direction during seismic actions or other shock forces and rolls out of its r...

A shock responsive fluid valve assembly capable of automatically closing a fluid valve in response to earthquake forces or other shock forces of a predetermined magnitude. The shock responsive valve assembly has a flow control mechanism having a cradle that holds a movable ball in a recess at a point perpendicular in relation to a horizontal base plate, where the ball can be rotated 360.degree. in any direction during seismic actions or other shock forces and rolls out of its recess at a predete...