Compressor diaphragm with axial preload

A wedge block apparatus for applying an axial preload on a compressor diaphragm comprising:

• an elongated first wedge block having an outer face and an inner face, each face extending along the length of the first wedge block, the inner face being substantially concave;
• and
• an elongated second wedge block having an outer face and an inner face, each face extending along the length of the second wedge block, the inner face being substantially concave, the second wedge block including a protrusion extending from at least a portion of the outer face,
• wherein the first wedge block is positioned substantially adjacent to the second block such that the concave inner faces face each other, the concave inner faces tapering toward each other along a portion of the length of the first and second wedge blocks so as to define a tapered region,
• wherein at least one cutaway is formed in at least one of the inner faces along a portion of the length of at least one of the first and second wedge blocks.

A method of reducing wear on a compressor diaphragm comprising the steps of:

• providing a substantially semi-cylindrical compressor shell having a radially outer peripheral surface, a radially inner peripheral surface, two circumferential ends, an axial upstream end and an axial downstream end, wherein the shell includes a slot extending along the radially inner peripheral surface from one circumferential end to the other circumferential end, wherein the shell further includes at least one recess located substantially at one of the circumferential ends;
• providing a diaphragm including an outer shroud with a plurality of airfoils extending radially therefrom, the outer shroud having a forward face and an aft face, wherein the outer shroud is received within the slot in the compressor shell;
• and
• applying a substantially axial force on one of the faces of the outer shroud in the direction of one of the axial ends of the shell, wherein the force is applied substantially at the horizontal joint at each circumferential end of the compressor shell.