Abstract: A heat pipe system particularly adapted for use with finned evaporators. In accordance with this invention, a separate liquid working fluid return conduit is provided which communicates with a liquid working fluid distribution means for distributing working fluid uniformly to all of the evaporator fins. Means are also provided in accordance with this invention for storing excess liquid working fluid either as a column of liquid within the liquid return pipe which is developed by a flow restrictor, or by selecting a distribution wick from a material having low capillary pressure which enables it to become saturated with liquid working fluid.

Abstract: An external heating system for a heat engine such as a Stirling cycle engine which permits thermal energy to be provided by solar energy or fuel combustion sources. The system employs a complexly shaped heat pipe evaporator section having an enclosed cavity for receiving solar energy and another section forming hollow fins which is exposed to hot combustion gasses. Accordingly, either heat source may be used to evaporate working fluid within the heat pipe which is transferred to the associated heat engine.

Abstract: The effectiveness of the lubrication system of a Stirling engine is maintained in a solar dish module for all directions of aiming of the dish by the journal mounting of the engine on the dish module with the center of gravity of the journaled mass eccentric to the journal axis along a particular radial. The engine has a sump which is disposed at a low point of the engine. The center of gravity of the journaled mass lies along a radial from the journal axis which intersects the sump. An additional counterweight is added to achieve the desired eccentricity.

Abstract: A corrosion resistant heat pipe construction which prevents the formation of corrosive oxides of sodium which may result when a sodium heat transport medium combines with oxygen within the heat pipe. In accordance with this invention, formation of such corrosive compounds is inhibited through the introduction of zirconium in the form of a fine thread woven into the heat pipe wick. When the wick is installed within the heat pipe, the zirconium will react with oxygen to form a relatively non-corrosive zirconium oxide. By introducing the zirconium thread into the wick material matrix, the fabrication of the heat pipe is carried out in accordance with present techniques, without requiring the addition of other components or operations.

Abstract: A sealing piston ring assembly for a Stirling engine which is effective to maintain the required pressure differential on opposite sides of the piston while still enabling free reciprocating movement of the piston within the cylinder. The piston ring assembly consists of a main annular ring member formed of metal and pair of sealing ring units on opposite end faces of the main ring member that are formed of low frictional material and are continuously urged into sealing engagement with the cylinder wall. Each sealing ring unit comprises a pair of thin axially engaged annular sealing ring members which are slotted so that they have spaced ends and are circumferentially expansible to maintain the necessary seal with the cylinder wall.

Abstract: An improved heat pipe comprising a duct having disposed at opposite ends thereof an evaporator with wick-lined hollow fins in the form of extended corrugations thereon, and operable to supply heat to the evaporator comprised of a gas combustor having an internal volume for containing the evaporator and combustion air for supply to a combustion chamber located therein; a wick capable of transporting liquid by capillary action lining substantially all internal surfaces of said heat pipe; an external heat sink operable to remove heat from the condenser; and a heat transport medium contained by said heat pipe. The evaporator is further comprised of a coarse porous material lining and completely filling the spaces within the hollow fins open to the evaporator for increased structural stiffness and ease of fabrication; and a porous mass completely filling the evaporator for increased compressive strength.

Abstract: An improved piston ring assembly, particularly for a Stirling engine, comprises a piston ring made from a TFE fluorocarbon such as Rulon which is disposed in a piston ring groove and is acted upon by an annular bi-metal element disposed between the groove and the ring. When the engine is cold, the bi-metal element urges the ring outwardly so that a flat radially outer surface of the ring is forced into face-to-face contact with the cylinder wall. When the engine has warmed up, the force of the element of the piston ring is relaxed and the thermal expansion of the piston ring maintains the outer surface of the ring in face-to-face contact with the cylinder wall.

Abstract: Improved lubricant control assemblies for reciprocating piston rods of an engine which prevent crankcase lubricant intruding into the cylinders and fluid from the cylinders from escaping into the crankcase. Each assembly comprises a tubular scraper fitting closely onto a piston rod and yieldably mounted within the bore between cylinder and crankcase through which the piston rod extends. The yieldable mounting is by means of a compliant housing. The compliant housing allows the scraper to be displaced radially and thereby follow limited radial displacement of the piston rod while maintaining substantially full effectiveness of the scraper's action on the reciprocating piston rod. The scraper is urged into forceful contact around the piston rod by means of a crown spring which is supported on a tubular part which attaches to the compliant housing.

Abstract: An improved construction for a thermal engine, particularly a Stirling engine, comprising a two-part drive shaft. One part of the drive shaft contains the swashplate mechanism and is journaled on the engine housing so that the component of force acting on the swashplate which induces bending of the drive shaft is reacted on the housing by the journaling of the one part of the shaft. The second shaft part is separate from but operatively coupled with the first-mentioned shaft part and has its own journal mounting on the housing. The operative coupling in the disclosed embodiment is by means of a spline connection between the two shaft parts which are in coaxial alignment. The second shaft part is journaled on a housing part which is separable from other parts of the housing on which the first shaft part is journaled.

Abstract: An improved heat pipe comprising a duct having disposed at opposite ends thereof an evaporator with wick-lined hollow fins in the form of extended corrugations thereon, and operable to supply heat to the evaporator comprised of a gas combustor having an internal volume for containing the evaporator and combustion air for supply to a combustion chamber located therein; a wick capable of transporting liquid by capillary action lining substantially all internal surfaces of said heat pipe; an external heat sink operable to remove heat from the condenser; and a heat transport medium contained by said heat pipe. The evaporator is further comprised of a coarse porous material lining and completely filling the spaces within the hollow fins open to the evaporator for increased structural stiffness and ease of fabrication; and a porous mass completely filling the evaporator for increased compressive strength.

Abstract: A heat exchanger stack apparatus for use on a remotely heated Stirling engine having a variable swashplate drive mechanism, which comprises rigidly combining a regenerator, a flexible heat exchanger, a short, rigid hot connecting duct and a cylinder. A heat exchanger stack apparatus for each cylinder of the engine is mounted on a drive mechanism housing with the regenerator adjacent to a cooler located within the drive mechanism housing. The cooler, regenerator and flexible heat exchanger are axially aligned providing a linear flowpath for the engine working fluid. Bellows and flexible tubes connected to the flexible heat exchanger provide axial and transverse flexibility to reduce thermal stresses within the heat exchanger stack apparatus.

Abstract: The pressure containment device for containing pressurized gas within a Stirling engine is characterized by enclosing a drive mechanism housing with a cylindrical pressure hull having first and second ends whereby a portion of the drive mechanism housing extends through the first end of the pressure hull and the second end thereof, is rigidly connected to the drive mechanism housing. An o-ring is used to seal the connection where the drive mechanism housing extends through the first end of the pressure hull to allow small axial and radial relative motions therebetween. An output shaft extends along the axis of revolution of the pressure hull and is supported by front and rear main bearings and a thrust bearing, all rigidly connected to the drive mechanism housing. A rotating shaft seal, also connected to the drive mechanism housing, prevents pressurized gas from escaping along the output shaft.