Claims
- 1. A nuclear qualified float level switch that can functions reliably inside a nuclear containment vessel in a harsh environment consisting of elevated temperature and pressure, a high level of ambient moisture, and heavy radiation dose, said nuclear qualified float level switch comprising:
- a) a reed switch with an exterior lead at each of its ends;
- b) two electrically insulated, mechanically protected conductors, each having a switch end connected to a lead of said reed switch and an alarm end located outside the containment vessel;
- c) a plurality of sealing and protecting means encasing said conductors, the reed switch, and the connections between them, wherein said plurality of sealing and protecting means seal out moisture and protect the components from mechanical damage, said plurality of sealing and protecting means of the two electrically insulated, mechanically protected conductors comprising at least mineral insulation encasing said conductors and stainless steel sheathing around said mineral insulated conductors;
- d) a guide tube containing:
- said reed switch, its leads, said connections thereto, and the switch ends of said two insulated conductors; and
- said sealing and protecting means for said reed switch and its connections; and
- e) a float surrounding said guide tube, said float containing a magnetic portion that causes said reed switch to be activated when said float reaches a predetermined level corresponding to a certain water level.
- 2. The nuclear qualified float level switch of claim 1 wherein the conductors are copper.
- 3. The nuclear qualified float level switch of claim 1 wherein the sealing and protecting means of the connections and the reed switch is heat shrink or other sleeves.
- 4. The nuclear qualified float level switch of claim 1 wherein a mechanically protective shield for said nuclear qualified float switch completely surrounds said nuclear qualified float switch with a mechanically rigid enclosure to protect the float, said shield having perforations that allow the rapid passage of surrounding fluid.
- 5. The nuclear qualified float level switch of claim 1 wherein said stainless steel sheathing is welded or brazed to one end of said guide tube so as to pressure-seal said guide tube and so as to preclude the entry of moisture inside the guide tube.
CONTRACTUAL ORIGIN
The present invention was conceived and developed in the performance of United States Government Contract DE-AC12-76-SN00052 with the Department of Energy. The U.S. Government has certain rights to this invention.
US Referenced Citations (3)