Multi-cylinder double-acting hot gas engine

Claim 1

A multi-cylinder double-acting hot gas engine of the kind in which the cylinders accommodate respective reciprocating pistons dividing the interior of each cylinder into a variable volume high temperature chamber and a variable volume low temperature chamber, the pistons being secured to respective piston rods extending through and being contacted by seals in seal-holding means, the seals for preventing leakage from the low temperature chambers past the piston rods, the low temperature chambers being defined in part by the seal-holding means, the piston rods being connected to respective crossheads outside the cylinders, the position of each of the crossheads remaining fixed relative to the position of the respective piston and piston rod, the engine comprising two main housing parts which are separably secured to each other by securing means, said seal-holding means being clamped between and housed by said two main housing parts, said seal-holding means including individual seal-holding assembly units, a respective one to each cylinder, said assembly units being of circular periphery greater in diameter than the interior of the respective cylinder, the cylinders being formed as part of one of said two main housing parts so that when the latter are separated the cylinders are separated from the respective pistons, and the pistons, the piston rods, and the seal-holding means remain with, and partially housed by, the other one of the said two main housing parts, and wherein each sealholding assembly unit also includes a guide for a respective one of the crossheads.