| 摘要 |
1,207,132. Cylinders; pistons. PHILIPS GLOEILAMPENFABRIEKEN N.V. 18 Oct., 1967 [21 Oct., 1966], No. 47388/67. Heading F2T. In a hot gas engine or other device including a piston 2 reciprocable in a cylinder 1 and separating two spaces 6, 11, each containing a medium, the piston being sealed by two piston rings 12, 13, each housed with axial clearance in a groove 12a, 13a in the piston or cylinder, means, e.g. grooves 17, 18 in the rings, are provided to prevent full engagement between one side of each ring and the opposing wall of the groove so that the ring seals in one axial direction only, the directions being opposite for the two rings, and the cylinder or piston has at least one axial groove 21 therein dimensioned and positioned such that one ring 12 is bridged by the groove during a part of each stroke of the piston to communicate the space 20 between the rings with the space 6 adjacent the ring 12. The piston 2 and a displacer 3 are connected to a driving mechanism (not shown) and the space 6 communicates with a space 7 through a cooler 8, regenerator 9 and a heater 10. The space 11 is a buffer space. The pressures in the spaces 6, 11 and 20 are indicated by lines 15, 16 and 19 respectively in the indicator diagram shown in Fig. 2. Piston ring 12 allows leakage towards space 6 and piston ring 13 allows leakage towards space 11. When the piston reaches point M in its downward stroke, ring 12 passes ends 22 of grooves 21 and the pressures in spaces 6 and 20 are equalized and if such pressure is higher than that in space 11 flow will occur past ring 13; thus the pressure in space 11 is determined by the position of the ends 22. In a modification, Fig. 6 (not shown), the length of grooves (21) is relatively small so that the spaces 6 and 20 communicate with each other during a small part only of the working cycle. In a further modification, Figs. 7 and 8 (not shown), the grooves 17 and 18 are on the sides of the rings 12 and 13 facing the space 20. In further embodiments, the invention is incorporated in a cold-gas refrigerator, Figs 9-15 (not shown), and in a double-acting piston machine, Figs. 16-20 (not shown). |
