GB1175314A - Apparatus for Encapsulating Electrical Conductors. - Google Patents

Abstract

1,175,314. Vacuum encapsulating electrical conductors. WESTINGHOUSE ELECTRIC CORP. 26 Aug., 1968 [17 Oct., 1967], No. 40603/68. Heading B5A. Electrically conductive means are encapsulated at least partially in a resin by loading a mould containing the conductive means into a vacuum chamber, evacuating the chamber using a first vacuum system, transferring the chamber to a second vacuum system, pouring resin into the mould while retaining the vacuum, with the second vacuum system, returning the vacuum chamber to atmospheric pressure and unloading the filled mould from the chamber. The resin components are mixed under vacuum in a mixing chamber, but this chamber may be under vacuum or at atmospheric pressure when the resin is poured into the mould. Apparatus as shown for carrying out the encapsulation comprises eight vacuum chambers, 18, 20, 22, 24, 26, 28, 30, 32 spaced around the perimeter of a horizontal rotatable carriage 12. The vacuum chambers which are identical in construction and are illustrated by reference to chamber 20 comprise a door 114 operable by piston 120, and locked by ring 116, a gate valve 126 and electrical heater connections 122 and are connected to the manifold 34 of the second vacuum system via pipes 76 and valves 90. The first vacuum system 36 is situated at position II over the carriage and the resin feed mechanism at V, both operating through the gate valve 126. In operation the vacuum chambers are indexed one position at a time by a drive means. The door 114 is open at position I, the mould containing the electrically conductive means is placed therein and the door is closed and locked. In position II, the first vacuum system 36 descends on to the chamber, coupling on to the gate valve 26 which opens and evacuates the chamber. The vacuum system 36 is raised leaving the chamber under vacuum. As the chamber moves to the next position valve 96 opens, connecting the chamber to the second vacuum system operating through manifold 34 and supply pipe 70. In positions III and IV, the mould is maintained under vacuum without processing to ensure maximum removal of entrapped air. In position V, the vacuum chamber is connected to resin supply means via a vacuum-tight link and resin is cast into the moulds. In position VI entrapped air is removed from the resin while the mould is maintained under vacuum, the pressure in the chamber is allowed to return to atmospheric at position VII and the mould is removed at position VIII and transferred to a curing station.