| 摘要 |
<p>1,190,782. Valves. MAX-PLANCKGESELLSCHAFT ZUR FORDERUNG DER WISSENSCHAFTEN E.V. 28 July, 1967 [29 July, 1966], No. 34943/67. Heading F2V. [Also in Divisions F4 and G3] Rise in the level of coolant in a cryostat above a predetermined value renders a magnet coil superconductive so that it closes a valve in a conduit supplying coolant to the cryostat from a pressurized reservoir. In Fig. 1, liquid helium, maintained at a constant pressure above atmosphere in a reservoir 14 by an automatic gas relief valve 6, is supplied through a duct 7 to a cryostat 1. The reservoir and cryostat are surrounded by vacuum and nitrogen-filled jackets and a vacuum jacket 10 surrounding the duct contains a copper radiation protection tube 8 and a cooling duct 9 conveying waste gas from the cryostat. The liquid in the cryostat rises to and is automatically maintained at a level at which it renders the solenoid of an electromagnetically operated valve 4 superconductive so that sufficient current flows to close the valve and prevent further supply of liquid. Leads to the solenoid from an electrical source 13 pass through duct 9. One arrangement of valve is shown in more detail in Fig. 2 in which the solenoid 25 contained in a perforated casing 24 operates a soft-iron core 26 against a spring 34 to close a conical valve 27 co-operating with the end of duct 7. The supply from duct 7 to the cryostat passes through minute perforations 32 to prevent loss of coolant due to formation of eddies. The maximum valve opening is adjustable by a ring nut 29. Modified valve arrangements are described in which (a) duct 7 passes around instead of through the solenoid, (b) metallic conductors attached to the solenoid make contact with the rising helium and render the solenoid superconductive before the level reaches the solenoid; (c) porous material, e.g. sintered metal, replaces perforated material 32; (d) the valve is located above the solenoid and surrounded by a vacuum chamber formed by welding at normal pressure a chamber containing activated charcoal.</p> |
