Metal bellows seal section and method to evacuate air during filling

An electrical submersible pump assembly, comprising:

• a pump;
• a motor operatively coupled to the pump for driving the pump;
• a seal section having a longitudinal axis and coupled to the motor, comprising:
• first and second end members spaced axially apart from each other,
• an outer bellows having a fixed end mounted to the first end member and a floating end that moves axially relative to the fixed end;
• a rigid, tubular interconnect member having an inner end within the outer bellows and an outer end fixed to the floating end of the outer bellows, the interconnect member having a cylindrical side wall extending between the inner and outer ends of the interconnect member, concentric with the axis, defining an interconnect annulus between the side wall of the interconnect member and the outer bellows, the interconnect annulus having a closed outer end and an open inner end;
• an inner bellows having a floating end secured to the inner end of the interconnect member and a fixed end secured to the second end member;
• an interconnect evacuation passage extending axially within the side wall of the interconnect member and offset from the axis, the interconnect evacuation passage having an interconnect evacuation passage ort at the inner end of the interconnect member that is offset from the axis, the interconnect evacuation passage having an interconnect evacuation passage opening in the side wall of the interconnect member that opens to the interconnect annulus adjacent the floating end of the outer bellows;
• a first end member evacuation passage extending from an exterior surface of the first end member to a first end member evacuation passage port on an end of the first end member that faces the inner end of the interconnect member, the first end member evacuation passage port being offset from the axis and aligned with the interconnect member evacuation passage port;
• a tube offset from the axis, the tube joining and protruding axially from one of the ports toward the other of the ports;
• the tube having an open tip that extends sealingly into the other of the ports while the outer bellows is in a contracted position and is disengaged from the other of the ports while the outer bellows is in an extended position;
• wherein
• the extended position defines a first flow path from the inner end of the interconnect annulus to the first end member evacuation passage and a second flow path through the interconnect member evacuation passage to the first end member evacuation passage to evacuate air from the inner and outer bellows prior to filling with motor lubricant;
• and
• the contracted position closes the first flow path and leaves the second flow path open.

A method of filling a seal section of an electrical submersible pump assembly, the seal section having a longitudinal axis, axially spaced apart first and second end members, a bellows having a fixed end mounted to the first end member and a floating end that moves axially as the bellows extends and contracts, a rigid sleeve located within the bellows, defining a sleeve annulus between the sleeve and the bellows, the sleeve having an outer end that joins and moves axially with the floating end of the bellows, the sleeve annulus having a closed outer end and an open inner end, the method comprising steps:

• (a) providing a sleeve evacuation passage within a side wall of the sleeve, the sleeve evacuation passage having an opening to the sleeve annulus adjacent the outer end of the sleeve, the sleeve evacuation passage having a sleeve evacuation passage port at the inner end of the sleeve;
• (b) providing a first member evacuation passage from an exterior surface of the first end member through the first end member to a first member evacuation passage port;
• (c) applying a vacuum to the first member evacuation passage and removing air from the interior of the bellows via a first flow path from the open inner end of the sleeve annulus to the first member evacuation passage port and also via a second flow path through the sleeve evacuation passage to the first member evacuation passage port, the removal of air causing the bellows to move from an extended position toward a contracted position;
• then
• (d) when the bellows reaches a selected intermediate contracted position, closing the first flow path and continuing to remove air along the second flow path;
• then
• (e) when the bellows reaches a desired fully contracted position, introducing lubricant into the bellows, causing the bellows to move toward the extended position and fill with the lubricant.