Pratt-whitney Canada Corp

Other

Andre Denis LeBlanc

Ioan Sasu

Michel Bellerose

Gilbert Ouellet

Rebecca A Heilman

Eric A Heilman

A diffuser for a centrifugal impeller assembly of a gas turbine engine includes a diffuser case having a plurality of vanes extending therein defining a plurality of circumferentially distributed angled passages in communication with an inlet space. Each vane includes a bleed port defined in a suction surface thereof, in proximity of the leading edge. The diffuser case includes a passive fluid communication defined at least partially through each one of the vanes between each bleed port and the inlet space upstream of the leading edge, such that air bled through the bleed ports is recirculated upstream of the leading edges to the inlet space to increase a surge margin of the diffuser.

Diffuser with enhanced surge margin

The automatic utensil wrapping machine is an apparatus for wrapping a napkin around one or more utensils for use as a place setting. The apparatus comprises a housing, a support frame and an assembly of elements mounted to the support frame. The assembly of elements includes a napkin lifting station, a napkin wrapping station, a napkin transfer station, a utensil transfer station, and a napkin folding station. The apparatus wraps each napkin around a predetermined amount of utensils without the need for human contact. The napkins are wrapped by first positioning a stack of napkins on the lifting station, then individually transferring napkins from the lifting station to the wrapping station. The utensils are then transferred from the individual cartridges and placed onto the napkin. Two opposing corners of the napkin are then folded over and the napkin is subsequently wrapped around the utensils.

Automatic utensil wrapping machine

The invention provides a diffuser assembly constructed of internal and external concentrically nested bowl-shaped shells for directing an outward flow of compressed air from a centrifugal compressor impeller to an axially rearward diffused annular flow. One of the shells is formed with grooves separated by seam edges and the other shell includes a smooth surface of revolution. The grooves on the one shell are closed by the other shell when the two shells are nested together and the seam edges are secured to the smooth surface by fastening means thus defining individual diffuser ducts extending from the compressor impeller to the outer shell edges. The shells can be easily manufactured from metal castings and sheet metal respectively, thereby eliminating much of the cost and the time involved in fabricating prior art diffusers of multiple formed pipes brazed to a separately machined hub. This construction can be easily reinforced for vibration control and the thickness of diffuser duct walls can be optimized for improved performance and minimum weight. The designers are freed from many of the constraints imposed by conventional diffuser design. The shape and cross-section of the diffuser ducts become completely independent of the manufacturing method, permitting the diffuser duct shape to be optimized for aerodynamic efficiency. The costs of production are reduced since tooling costs and manufacturing complexity are dramatically reduced when only two shell parts are required.

Integrated duct diffuser

A compressor for a gas turbine engine, comprising a casing having an inner surface defining a plurality of circumferentially spaced-apart grooves adjacent the tips of a row of rotor blades. Each groove as a depth which is less than half the width thereof in order to increase surge margin at off design points without affecting the performance of the compressor under normal operating conditions.

Low aspect ratio compressor casing treatment

Compressor 14 of a gas turbine engine has a final centrifugal stage 18 discharging air into annulus 20. Diffuser 20 are straight and of frustoconical shape receiving air from the annulus. A side cut produces opening 38 in the side of each diffuser. Much of the flow exits through, and is directed by these openings.

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St. Bruno, Canada

Andre Denis LeBlanc