摘要 |
<p>The device has a piston (2) provided with piston heads, and piston skirts (4, 5) extending from one of the piston heads in a direction of cylinder heads (8, 9), where openings are provided in the corresponding piston skirts. One of the openings aligns with an inlet opening (14) correspondingly provided in a cylinder (1) when a given position of the piston is in proximity of one of the cylinder heads while the other opening aligns with another inlet opening (15) correspondingly provided in the cylinder.</p> |