| 摘要 |
<p>The casing consists of two parts, namely a casing inner part (11) and an outer part (12) which surrounds the former, the two parts forming a cavity (13). On the inner part of the casing (11), on both sides of the cavity two annular grooves (14, 15) with a rectangular cross-section are provided on the external periphery, and a torus (16, 17) engages to mate with the grooves on the inner circumference of the outer part (12). The inner and outer part of the housing consist of materials having a different hardness with different thermal expansion coefficients, so that when the casing is heated a tension is created between the tori and the grooves in such a way that the cavity (13) is sealed off practically hermetically from the outside.</p> |
