Scroll structure of centrifugal compressor

Patent metadata

Field	Value
Publication number	US-9562541-B2
Application number	US-201213981042-A
Country	US
Kind code	B2
Filing date	Jan 27, 2012
Priority date	Mar 17, 2011
Publication date	Feb 7, 2017
Grant date	Feb 7, 2017

Abstract

An axial cross-sectional shape of a scroll flow path 13 is a roughly circular shape, a diffuser outlet connected to the roughly circular shape is shifted to a position which is closer to a circle center than to a position of a tangent line to the circular shape and which does not reach the circle center, the circular shape is formed from a scroll chamber 30 which juts out in the axial direction relative to the position of the diffuser outlet 11 a and a shift chamber 32 that forms a remainder of the roughly circular shape in a direction opposite to the scroll chamber 30 , and the shift chamber 32 is at least formed on the scroll flow path 13 of a winding end portion 19 in a circumferential direction of a spiral.

First claim

The invention claimed is:

1. A scroll structure of a centrifugal compressor comprising a rotary impeller and a diffuser which is provided on an outer circumferential side of the impeller, and a scroll flow path which is formed in a spiral shape that connects to an outer circumference of the diffuser, and a diffuser outlet connected to the scroll flow path, wherein
an axial cross-sectional shape of the scroll flow path has a roughly circular shape,
the diffuser outlet is connected to the scroll flow path a position that is aligned with a tangential portion of the roughly circular cross section,
the cross sectional shape of the scroll flow path changes such that the relative position of the diffuser outlet is aligned closer to the center of the roughly circular cross section but is not aligned with the center of the cross sectional shape,
the roughly circular cross sectional shape is formed from a scroll chamber which juts out in a first axial direction relative to the position of the diffuser outlet and a shift chamber that forms a remainder of the roughly circular shape in a second axial direction opposite to the scroll chamber, and
the shift chamber is at least formed on the scroll flow path of a winding end portion in a circumferential direction of a spiral when a winding angle θ in a clockwise direction is set so that a line connecting a position of a tongue portion and the circle center, in a view from an axial line direction of the rotary impeller is at a position of approximately 60 degrees as a winding angle θ of the scroll flow path, the shift chamber is formed beginning at a position approximately 180 degrees preceding the winding end portion of the scroll flow path in a circumferential direction, the dimension of the shift chamber increasing so as to reach maximum at a position of approximately 360 degrees, the dimension of the shift chamber increasing linearly or parabolically as a circumferential angle increases.

2. The scroll structure of a centrifugal compressor according to claim 1 , wherein the shift chamber is further formed in the scroll flow path of a winding start portion.

3. The scroll structure of a centrifugal compressor according to claim 2 , wherein
a shape of a connection opening of the scroll flow path of the winding start portion to the winding end portion is formed in a flat shape having a height that is equal to a width of the diffuser outlet,
the shift chamber is provided on one side of the flat shape, and
a height of the shift chamber varies in the circumferential direction.

4. The scroll structure of a centrifugal compressor according to claim 1 , wherein the shift chamber is formed on the entire scroll flow path in the circumferential direction.

5. A scroll structure of a centrifugal compressor comprising a rotary impeller and a diffuser which is provided on an outer circumferential side of the impeller, and a scroll flow path which is formed in a spiral shape that connects to an outer circumference of the diffuser, and a diffuser outlet connected to the scroll flow path, wherein
an axial cross-sectional shape of the scroll flow path has a roughly circular shape,
the diffuser outlet is connected to the scroll flow path in a position that is aligned with a tangential portion of the roughly circular cross section,
the cross-sectional shape of the scroll flow path changes such that the relative position of the diffuser outlet is aligned closer to the center of the roughly circular cross section but is not
aligned with the center of the cross sectional shape,
the roughly circular cross-sectional shape is formed from a scroll chamber which juts out in a first axial direction relative to the position of the diffuser outlet and a shift chamber that forms a remainder of the roughly circular shape in a second axial direction opposite to the scroll chamber, and
the shift chamber is at least formed on the scroll flow path of a winding end portion in a circumferential direction of a spiral, and
the shift chamber is further formed in the scroll flow path of a winding start portion.

6. The scroll structure of a centrifugal compressor according to claim 5 , wherein
a shape of a connection opening of the scroll flow path of the winding start portion to the winding end portion is formed in a flat shape having a height that is equal to a width of the diffuser outlet,
the shift chamber is provided on one side of the flat shape, and
a height of the shift chamber varies in the circumferential direction.

7. The scroll structure of a centrifugal compressor according to claim 5 , wherein when a winding angle θ in a clockwise direction is set so that a line connecting a position of a tongue portion and the circle center, in a view from an axial line direction of the rotary impeller is at a position of approximately 60 degrees as a winding angle θ of the scroll flow path, the shift chamber is formed beginning at a position approximately 180 degrees preceding the winding end portion of the scroll flow path in a circumferential direction, the dimension of the shift chamber increasing so as to reach maximum at a position of approximately 360 degrees, the dimension of the shift chamber increasing linearly or parabolically as a circumferential angle increases.

Assignees

• Iwakiri Kenichiro
• Tomita Isao
• Shiraishi Takashi
• Mitsubishi Heavy Ind Ltd

Inventors

• Iwakiri Kenichiro
• Tomita Isao
• Shiraishi Takashi

Classifications

• F04D29/44 Primary

  Fluid-guiding means, e.g. diffusers · CPC title

• F04D29/441 Primary

  especially adapted for elastic fluid pumps · CPC title

• F04D29/667

  by influencing the flow pattern, e.g. suppression of turbulence · CPC title

• F04D29/4206

  especially adapted for elastic fluid pumps · CPC title

• F05D2250/52

  Outlet · CPC title