| 摘要 |
The valve partic. for steam pipes in nuclear power stations has the plug coupled to a double-acting piston incorporating an armature, subjected in the open position to the effect of an external holder magnet. Between the moving armature inside the pressure chamber and the magnet a non-magnetic section of steel sheet forms part of the chamber wall, and in the open position of the valve the armature bears against it. On the outside, this section is supported for its whole surface by the magnet clamped to the chamber housing. The magnet comprises a thick-walled pot with its mouth bearing against the sheet, with a cylindrical permanent magnet inside bearing against the base of the pot, and a core of ferromagnetic material is pressed against the permanent magnet. The outside of the core, and of a ring of non-magnetic material filling the annular gap between core and inner pot wall, lie in a single plane with the pot end face and flush with it. |
