| 摘要 |
This invention relates to a pressure/vacuum system apparatus; one part of such apparatus being an economical fitting, another part being operating mechanism, another part being a means to join such fitting to such operating mechanism in a substantially fluid-tight manner, all operable to perform certain functions together without shutting down the pressure/vacuum system they are attached to. Some installations require many fittings. In many instances an operating mechanism may be attached to an operated fitting for only short periods of time and then disconnected therefrom, leaving the operated fitting in (a) a dormant condition in relation to its functions to the pressure/vacuum system, or (b) in a functional condition in relation to the pressure/vacuum system. Thus, in many cases a single operating mechanism may be used for operating each of a number of different fittings from time to time as required. Although the operating mechanism may be rather expensive, the fittings economy of the large number of fittings on which the mechanism may be used selectively lends economical practicality to the invention. The operating mechanism and the fitting may be joined in an essentially fluid-tight manner and/or separated and a fluid-tight member may be installed or removed from the fitting and the functions of the apparatus performed without substantial fluid transfer to or from the areas ambient to the apparatus and without shutting down the pressure/vacuum system.
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