Abstract: Apparatus and method for protecting a producing oil well's sucker rod string from wear as the rod string reciprocates in the well's tubing string. Each rod guide has a network of passages encased within the body of the rod guide. As the sucker rods and rod guides move up and down through the tubing string, produced fluid is channeled through tunnels in the passages to exit ports from which the fluids are discharged at high velocity away from the guide. The fluid exits with suffficient force to push the rod string away from the tubing string at each exit port. In this way the streams of fluid tend to centralize the rod string near the center of the tubing string thereby averting contact between not only the rod string and the tubing string, but also between the guide itself and the tubing string. The discharged fluid also provides lubrication between the guide and tubing string in the event that contact between the components does occur.

Abstract: Apparatus for coating the endmost threaded section of a pipe with corrosion resistant powder coating material by rotating the pipe and spraying the section to be coated with electrostatically charged, air-entrained powder through two stationary nozzles, one of which is directed at the section to be coated, and the other of which is directed at the chamfered end of the pipe. To prevent overspray of the powder from contacting the pipe adjacent to the area to be coated, a pair of air nozzles are directed at the area of the pipe adjacent to the area to be coated.

Abstract: A standard size, steel oil well sucker rod coupling is machined to decrease its external diameter, producing a constant diameter along its length. Then, the coupling is machined to produce chamfers or bevels around the circumference on the ends, such that the diameter at the radial faces is less than at the body of the coupling. Next, abrasive blast-cleaning of the coupling produces a uniform, angular, anchor profile along the machined areas on the exterior of the coupling. Finally, a specially selected, fusion bonded, resinous coating is applied to the exposed surface. The radial faces may or may not be coated. The unique protective coatings impart abrasion resistance in a pumping oil well and serve as an electrical barrier to preclude electrochemical, corrosive, attack of the mild steel coupling core. Extended service life of the coupling is achieved.

Abstract: A standard size, steel oil well sucker rod coupling is machined to decrease its external diameter, producing a constant diameter along its length. Then, the coupling is machined to produce chamfers or bevels around the circumference on the ends, such that the diameter at the radial faces is less than at the body of the coupling. Next, abrasive blast-cleaning of the coupling produces a uniform, angular, anchor profile along the machined areas on the exterior of the coupling. Finally, a specially selected, fusion bonded, resinous coating is applied to the external surface including each radial face. The unique protective coatings impart abrasion resistance in a pumping oil well and serve as an electrical barrier to preclude electrochemical, corrosive, attack of the mild steel coupling core. Extended service life of the coupling is achieved.

Abstract: Air is flowed within an annulus fluidly connected to the load end of a pipe to be coated. A premeasured charge of powdered coating material is suspended in an injection airflow and then injected into the annulus. Spiral flow of the air and particles of coating material in the annulus is induced by successively jetting air into the annulus at selected angles to axial flow. The resulting powder cloud has spiral annular movement within the annulus toward the load end of the pipe. An optional conical deflector at the load end deflects the spiral cloud toward the wall of the pipe. The pipe is rotated counter to the tangential or circumferential component of the spiral flow. The nonaxial circumferential component of the spiral flow helps reduce the number of holidays, and insures that the coating material is deposited evenly through the length of the pipe for a uniform coating thickness. The powder cloud is much longer than the pipe. The excess coating material exiting the pipe discharge end is recycled.

Abstract: A transferred electron device includes a novel cathode giving improvement in the dc to microwave conversion efficiency over a wide temperature range. The cathode comprises a narrow n.sup.+ semiconductor zone next to the device active region or layer and, next to the n.sup.+ zone, a high field contact which includes a region of semiconductor.

Abstract: This disclosure relates to two-terminal solid state microwave devices, such as transferred electron and avalanche effect devices, comprising a high-conductivity semiconductor substrate formed over at least a part of one major surface with an active layer of semiconductor material, a first contact providing electrical contact with the active layer to define the active region of the device, and a second contact on the same side of the substrate, providing a relatively low impedance contact to the substrate in operation of the device at the operating bias current for the active region.To simplify fabrication, both contacts may have substantially identical structures with the second contact also overlying the active layer.

Abstract: A doppler radar system comprises a solid state microwave source which is pulsed on and off with a duty cycle typically around 10.sup.-3. The microwaves are transmitted towards a nearby target with a small amount supplied to a mixer also supplied with signals received from the target. The mixer output is passed through a gate opened in coincidence with the mixer pulsed output, and supplied to an integrator whose output forms a doppler signal representing target velocity. Target directionality is found by providing two channels fed in quadrature phase.