| 摘要 |
<p>The case is a one piece shell based on a metal support ring for the peripheral wall, moulded into a relatively thick rim and thin base of a heat mouldable material (e.g. a variety of natural or synthetic rubbers esp. incl. silicone rubber). The case is enclosed by the meter glass which is sealed by a rim fillet of the same material as the case. It may have an external rigid jacket and access to the interior through a tube vulcanised into ahole in the side wall. Relatively cheap reliable method of sealing.</p> |
