Abstract: This invention discloses a system for initiating and enhancing combustion of fuel and fuel-air mixtures by discharging electrical energy in a spark gap. The energy to breakdown the spark gap is supplied by a high voltage direct current source which supplies a voltage high enough to cause initiation of the spark without the need for an intermediate transformer. Control of the high voltage is by way of a semiconductor switch, which is preferably a bulk photoconductive switch. Such a switch is capable of withstanding the high voltage applied across it when it is switched off. There may also be provided a further source of high voltage which supplies energy to the spark gap at a lower voltage then the first source after the spark has been initiated. Thus the length of time the spark lasts for may be controlled. This is particularly useful for use with lean fuel mixtures for fuel economy or with diluted fuel mixtures diluted through exhaust gas recirculation for reduced emissions.

Abstract: An improved subsea tubing hanger having a body with an external shoulder for landing on a seat within a subsea wellhead housing, locking ring carried on the hanger to engage an interior recess of the wellhead housing, with an actuator ring for setting the locking ring. A preloading mechanism includes an extendible ring cooperating with the locking ring to prevent any movement of the tubing hanger when engaged and operable by torque supplied by the running tool. The improved tubing hanger running tool includes a body secured to the tubing hanger by conventional latching ring with a rotatable outer sleeve having an interior helical groove. A piston positioned on the running tool body and operated by hydraulic fluid pressure has an exterior pin which coacts with the helical groove to provide torque to the actuating ring and preloading ring of the tubing hanger.

Abstract: This invention provides an ignition system for a spark initiated internal combustion engine such as an Otto cycle engine. High voltage pulses are generated, for instance by way of an ignition coil, and these are passed to the respective spark gaps by way of semiconductor switches. These semiconductor switches are preferably bulk photoconductive switch devices which each comprise a light source and a photosensitive switch. These devices are under the control of control circuitry which activates and deactivates the light sources approximately to distribute the high voltage pulses to the spark plugs. These switches may be used to improve the rise time of the potential across the spark gap or to generate a plurality of sparks in one gap from a single pulse.

Abstract: An improved length compensating joint suitable for use in repairing pipelines includes an inner tubular member, an outer tubular member which receives the inner member in close fitting engagement, seals disposed radially and axially between the inner and outer members define annular piston areas for providing selective relative motion between the inner and outer members, a pressure responsive locking piston with a camming surface for urging gripping elements into locking engagement with the inner member, a metal-to-metal seal between the inner and outer members which can be deenergized during extension or retraction operations and a test port for verifying the integrity of the metal-to-metal seal after installation. Additionally, a second embodiment provides an alternative metal-to-metal seal configuration which can also be deenergized during extension and retraction operations.

Abstract: A fail-close hydraulically actuated control choke includes a choke with inlet and outlet flow passages intersecting in a cylindrical flow chamber. A reverse acting trim configuration which utilizes downstream pressure to assist in closing includes a flow cage with a wear sleeve of tungsten carbide shrink fitted therein is reciprocable within the flow chamber to control flow between the inlet and outlet flow passages. The flow cage is closed at one end with a stem extending therefrom which is reciprocated by a fail-close hydraulic actuator. The hydraulic actuator includes a pressure responsive piston in combination with a torque operated driving mechanism. The driving mechanism is positioned within the piston and includes a traveling nut assembly to allow manual positioning of the stem and flow cage independently of the position of the piston.

Abstract: A landing ring (60, 96) for use in stacking hangers (14, 40, 80) in a wellhousing 10. Each landing ring can be connected to a downwardly facing landing shoulder on a layer in such a way as to allow relative lateral movement between the ring and layer. The lower surface of each ring may be tapered to engage a correspondingly shaped surface on the upper surface of another hanger on which it is to land. The arrangement points a layer to be aligned laterally in the housing independently of the alignment of a layer on which it is landed.

Abstract: A valve assembly has a body portion (11) which can be removably receivable in a receptacle (10). The body carries the valve element such as a gate which controls fluid through a flowpath in the body. The openings of a flowpath in the receptacle accommodate annular sealing members (23, 24) which are movable axially in the opening. Means such as a lever arrangement (32, 33) are coupled to each sealing members and are contactable by the body (11) on its insertion in the receptacle such that the sealing members are moved axially toward the body to seal around the flowpath openings of the body.

Abstract: A gate valve includes a gate cavity (18), a flowbore (14, 16) communicating with the gate cavity and a gate (20) for opening and closing flow through the flowbore. A valve seat (42) is provided on each side of the gate. Each valve seat (42) has inner and outer C-ring seals (52, 54) on its end surface for sealing against a body sealing surface (46). The seals are energized by an assembly which includes a disc spring (62) disposed around the valve seat (42).

Abstract: An improved wellhead annulus seal installation tool and preload retention apparatus is disclosed particularly adapted for metal-to-metal seals. The seal installation tool includes a telescoping mandrel with a torsion spring attached and a torque sleeve rotatably mounted thereon with a pair of antirotation pins for limiting the rotation of the torque sleeve, a resilient seal for sealing the lower portion of the tool inside the hanger and torque pins for transmitting the torque and axial movement of the tool to the preload retention apparatus. The preload retention apparatus includes an upper body with an annulus packoff seal which may be resilient or metal-to-metal and a driving ring threaded thereon. An expansible lock ring in carried on the driving ring with an expander ring thereabove which coacts with the seal installation tool to thereby lock the annulus packoff seal inside the wellhead.

Abstract: An improved pressure balanced choke valve with a reversible cage style trim suitable for installation in production flowlines where it may be desired to later reverse the flow direction and use the well for water injection. The valve body has end connections machined thereon and a central bore for sealingly receiving a reversible cartridge assembly containing the cage style trim. The cartridge assembly is sealed against the valve body cavity by metal-to-metal seals and is easily removed for flow reversal by removal of a simple retainer cap. The cartridge assembly uses an inner sleeve movable within a cage type trim to control the flow. The cartridge is surmounted by a bonnet assembly utilizing a handwheel operated traveling nut assembly to control movement of the inner sleeve.