Abstract: A mechanical and electrical pressure sensor wherein the mechanical part includes a fluid pressure chamber with a magnetic, electrically conductive diaphragm moving out-of-contact with a stationary contact in the presence of pressure and into contact therewith in the absence of pressure or because of energizing of a cooperatively acting magnetic coil. The electrical circuit connected to the coil includes a clocked flip-flop, the output of which is high during a time interval when the contacts are open (coil energized) and which is low when the contacts are closed (coil deenergized). The duty cycle of energized time to total time is a measure of average coil winding current, and, hence, sensed pressure. The ratio of energized intervals to total intervals develops a useful digital measurement of pressure readily useful in a computer.

Abstract: A dimmer circuit for providing gate signal to a gated semiconductor connected for at least partial bypass operation of a ballast element of an HID lamp, the gate signal being derived from a high frequency voltage in a predetermined range. The high frequency voltage is separated from other frequencies and converted to a voltage proportional to the frequency. The voltage is then converted to a pulse within the timed operational limits of the line voltage for gating the semiconductor, and hence producing a brightness of the lamp between predetermined limits of full dim to full bright. Preferably, the high frequency voltage carrying the control information arrives superimposed on the line voltage to thereby avoid having to use a separate set of leads to the lamp to provide light level control signalling.

Abstract: A ceiling mounted support structure for mounting light fixtures, louvers, and the like, including at least one support piece mounted or supported by at least one building ceiling support, the piece having an elongate slot therein in which an enlarged end of a flipper bar rotates. The flipper bar rotates upwardly to permit the fixture part to be supported to pass upwardly therepast and rotates downwardly to provide the in-place support for the fixture part.

Abstract: A dimmer circuit for an HID lamp is provided for supplying a square wave current therethrough at a constant frequency, but whose duty cycle is variable dependent on a sensed current level. The circuit employs a first pair of transistor switches for reversing polarity through the lamp at a low frequency rate. Associated with each of those transistors is a circuit having a transistor switch connected to a drive circuit employing a timer network. The timer network produces an output that is a square wave, the leading edge of which occurs at regular intervals at a high frequency rate. The trailing edge occurs dependent on a dim/bright voltage setting and upon the amount of current through a sensing resistor in series with the lamp.

Abstract: A circuit for providing remote control at a plurality of locations for a lighting system, such control functions including on/off, dimming intensity and rate of dimming. Visual indication of take control is also provided.

Abstract: A protection circuit for producing one or more triggers in the presence of a monitored overvoltage condition employing photodiode networks for sensing the voltage overload, phototransistors responding to the photodiode outputs and operating gated semiconductors, which, in turn, discharge capacitors for trigger production. Separate networks are provided for each ac polarity operation. Monitoring may be with respect to supply voltage, power supply output voltage or one or more independent voltages.

Abstract: A high frequency drive circuit operating as a push-pull, Class C oscillator for driving a high-intensity, gaseous discharge lamp and avoiding the use of a relatively large ballast coil. A highly stable power supply for operating in conjunction with such circuit is also provided.

Abstract: A packer assembly for sealing against the wall of well pipe including a reverse beveled washer face adjacent a straight resilient packer face, thereby providing an internal gap for vertical extrusion when the packer is radially expanded and, hence, retard vertical extrusion between the hard packer components and the well pipe wall.

Abstract: A packer assembly for sealing against the wall of well pipe including a washer having reverse beveled and beveled faces. The reverse beveled face is adjacent to a straight resilient packer face, and the internal gap created thereby retards vertical extrusion of the resilient packer section under pressure. The beveled face abuts a radially expanding segmented packer ring, causing the packer ring to expand against the well pipe when the packer assembly is operated, thereby limiting vertical extrusion of the resilient packer section under high pressure conditions.

Abstract: A fluid lifting apparatus operable by air pressure applied alternately to first and second pairs of cylinders each of said cylinders having a main body part, a barrel and a bottom chamber in communications with a bottom inlet. Pressuring of the main body part of the chamber, closes a check valve at the inlet and forces fluid from the main body part, through a fluid flow valve, through the chamber and up the barrel to a production tubing segment and hence to the next higher cylinder. Emptying of the main chamber closes the fluid flow valve to prevent air from the production tubing. However, the valve is positively opened once fluid flow in the bottom chamber from the inlet is reinstituted. Air vent means to the surface and/or to the well annulus rapidly depressurizes the cylinders and hence speeds cycling between the alternate cylinder pairs.

Abstract: A perimeter lighting system using monosymmetrical quasi-indirect light fixtures recessed in the ceiling of a room, near the walls, to direct light toward the walls and thereby cause it to be reflected from them at optimum elevation for maximum overall lighting of the typical working area in the room, thereby producing a high contrast rendition factor over much of the work task zone.