Patent GB-725227-A (GB)
Title: Improved means for cooling the upper pistons of vertical opposed piston compression ignition engines
IPC: F01P3/10
Filed: 1953-06-10
Abstract: 725,227. Pistons. HARPER, W. A., POUNDER, C. C., and REBBECK, Sir F. E. June 10, 1953, No. 15948/53. Class 122 (1). A vertical opposed-piston compression-ignition engine in which coolant is circulated through the interior of the upper piston 1 is provided with an agitating or scraping means 3 within the piston 1 for breaking up fur or deposit as it forms inside the piston, so that the fur or deposit may be carried away in the coolant stream. In Fig. 2, the scraping means, which is attached to and rotated in the piston by the coolant pipes 16, 17, is formed in four segments 14 each provided with ribs 33 to scrape the piston and form a circuitous passage 32 which receives the coolant through an opening 31 at the upper circumference of the segment. The coolant flows over the surface of the segment, as illustrated in the development of Fig. 5, towards the centre where it enters the return pipe 16 which is concentric with the delivery pipe 17 and separated from it by a wall 34. A further wall 4 insulates the pipe 17 from the coolant in the interior of the piston, and the space between the wall 4 and the pipe 17 and that between the wall 34 and the pipe 16 is exhausted and sealed or filled with a heat-insulating or non-conducting substance. The coolant entering the piston through the annular passage between the pipe 17 and the wall 34 is discharged through branches 5 which may be set to give it a swirling motion. A motor 9, Fig. 1, mounted in the'interior of a yoke 2 attached to the piston, rotates the pipes 16, 17 and is driven by the coolant which enters the yoke through a pipe 10, the drive from the motor being transmitted through gears to a worm which rotates a worm wheel 8 clutched to the pipe 17 and the casing 4, and the rotation being indicated by a disc 15 on the top of the pipe 16. The scraper may be rotated, when the engine and coolant supply have been stopped, by hand cranking a shaft 19, Fig. 2, which is connected by a chain 29 to the worm shaft 30. Coolant is discharged from the pipe 16 through a pipe 11, and the inertia force on the pipes is reacted by a spring 12 acting on a bearing 13 at the top of the pipes. Instead of rotating the scraper continuously, an intermittent rotation may be effected by a chain-rack 25, Fig. 6, fixed on a pillar 26 mounted on the exhaust belt 27. The rack 25 rotates a free-wheel sprocket 24 mounted on the yoke, and the sprocket-shaft 22 transmits the rotation through a further sprocket 21 and a chain 38 to a sprocket 20 on the shaft 19. In a construction in which the pipes are not rotated, Fig. 8, the scraping element comprises a chain sack 39 suspended from a hoop 43 which rests loosely on a tapered part of the piston so that the rack can move under its own inertia and receive a slight circular movement from the swirling coolant. In various modifications, not illustrated, the casing 4 may be provided with a clutch and a screw which receives intermittent rotation from a stationary nut to rotate the scraper. The scraper may consist of wire or plastic bristles or thin tongues (resembling a painter's graining comb) of metal or other material attached to a rotor, reciprocatory member or coolant circulator in the piston, or may comprise small balls or pieces of metallic, plastic or other material which are prevented from being entrained in the coolant. If the piston is made with an external flange for attach. ment to the yoke 2, the circulator may be made in one piece with a single inlet passage to the path 32 which would traverse the whole circulator.