CA1189492A - Diaphragm construction for a multi-stage compressor - Google Patents
Diaphragm construction for a multi-stage compressorInfo
- Publication number
- CA1189492A CA1189492A CA000379562A CA379562A CA1189492A CA 1189492 A CA1189492 A CA 1189492A CA 000379562 A CA000379562 A CA 000379562A CA 379562 A CA379562 A CA 379562A CA 1189492 A CA1189492 A CA 1189492A
- Authority
- CA
- Canada
- Prior art keywords
- stage
- diaphragm
- flow path
- sections
- confronting
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
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- Structures Of Non-Positive Displacement Pumps (AREA)
Abstract
DIAPHRAGM CONSTRUCTION FOR A MULTI-STAGE COMPRESSOR
Abstract of the Disclosure The diaphragm component in a multi-stage centrifugal compressor associated with a narrow flow clearance thereat has each of its semi-annular sections constructed of a pair of separate pieces joined by a rail fit enabling at least one of the separate pieces to be of cast composition.
Abstract of the Disclosure The diaphragm component in a multi-stage centrifugal compressor associated with a narrow flow clearance thereat has each of its semi-annular sections constructed of a pair of separate pieces joined by a rail fit enabling at least one of the separate pieces to be of cast composition.
Description
DIAPHRAGM CONSTRUCTION FOR A MULTI-STAGE COMPRESSOR
Technical Field The field of art to which the invention pertains comprises the art of turbo machinery and component con-struction therefor.Background of the Invention In any manufactured product sold in competitive markets, the cost of producing the produc-t es-tablishes the base from which the manufacturer can profitably compete.
In complex structures such as in a multi-stage centrifugal compressor, the cost of each individual component becomes a significant factor contributing ultimately toward that base. At the same time, details of construc-tion as well as closely held tolerances on the various component confi~ura-tions need to be adhered to in order to assure performancestandards of the equipment.
A component problem in a multi-s-tage centrifugal compressor has been the construction of the stationary diaphragm which serves between impellers to provide support for the stationary elements such as the diffuser faces, guide vanes, return bend, labyrinths, etc. Typically, each semi~annular section of the diaphragm has been cast as a single piece split at its horizontal center line which is located with rabbet fits and secured via tie bolts. ~owever, on small compressors incurring a flow path clearance on the order of one-half inch or less, casting of the diaphragm sections becomes impractical because of prohibitively costly coring problems normally associated with a-ttempting to main-tain such a minimal clearance. Consequently, it has become .~
g~
c~lstomary, particularly on small compressors having one half inch or less Elow path clearance requirements, to avoid the coring expense by construc-ting the diaphragm sections via machining and brazing as a substitu-te for the otherwise less costly casting. Despite recognizing the cost advantages of casting, it has not been known heretofore how to effectively exploit the use thereof under conditions oE close clearance requirements.
The present invention resides in a multi-stage barrel type centrifugal compressor for compressing fluid flow including a vertically split housing defining a flow path from an inlet to an outlet, a multi-stage impeller in the flow path, and an annular stationary diaphragm encircling the multi-stage impeller in axially contiguous portions at each intermediate stage thereof for providing continuity of the flow path between successive of the stages and comprised of oppositely positioned confronting sections which between at least one stage constrict the -transverse flow dimensions at a selected location of the flow path to less than about
Technical Field The field of art to which the invention pertains comprises the art of turbo machinery and component con-struction therefor.Background of the Invention In any manufactured product sold in competitive markets, the cost of producing the produc-t es-tablishes the base from which the manufacturer can profitably compete.
In complex structures such as in a multi-stage centrifugal compressor, the cost of each individual component becomes a significant factor contributing ultimately toward that base. At the same time, details of construc-tion as well as closely held tolerances on the various component confi~ura-tions need to be adhered to in order to assure performancestandards of the equipment.
A component problem in a multi-s-tage centrifugal compressor has been the construction of the stationary diaphragm which serves between impellers to provide support for the stationary elements such as the diffuser faces, guide vanes, return bend, labyrinths, etc. Typically, each semi~annular section of the diaphragm has been cast as a single piece split at its horizontal center line which is located with rabbet fits and secured via tie bolts. ~owever, on small compressors incurring a flow path clearance on the order of one-half inch or less, casting of the diaphragm sections becomes impractical because of prohibitively costly coring problems normally associated with a-ttempting to main-tain such a minimal clearance. Consequently, it has become .~
g~
c~lstomary, particularly on small compressors having one half inch or less Elow path clearance requirements, to avoid the coring expense by construc-ting the diaphragm sections via machining and brazing as a substitu-te for the otherwise less costly casting. Despite recognizing the cost advantages of casting, it has not been known heretofore how to effectively exploit the use thereof under conditions oE close clearance requirements.
The present invention resides in a multi-stage barrel type centrifugal compressor for compressing fluid flow including a vertically split housing defining a flow path from an inlet to an outlet, a multi-stage impeller in the flow path, and an annular stationary diaphragm encircling the multi-stage impeller in axially contiguous portions at each intermediate stage thereof for providing continuity of the flow path between successive of the stages and comprised of oppositely positioned confronting sections which between at least one stage constrict the -transverse flow dimensions at a selected location of the flow path to less than about
2~ one-half inch. An axially extending tie bolt means secures the axially contiguous portions of the diaphragm. Each annular portion of the diaphragm of the at least one stage is supported by the tie bolt means independent of the housing and is comprised of the confronting sections being joined interfitted together in a rail fit at a location along the flow path displaced from the constricted flow dimension with at least the larger of the confronting sections being of a cast metal composition.
By means of the invention, the low cost advantage of diaphragm casting for a multi-stage centrifugal compressor has been largely retained, even under conditions of close dimensional clearances in the flow path. Where the prior art constructions dictated substitution of the more expensive coring and/or machine-brazing approaches in order to meet dimensional requirements, it is possible by means hereof to construct the diaphragm in a manner largely preser~ing the 111'1l 1 use of a casting without the need for -the more costly coring.
By fabricating the diaphraym in this manner, the need for expensive coring in the constricted flow area is ellminated while still enabling the bulkier of the components, including -the vane section thereon, to be cas-t. The remain-ing return bend section can -then be machined from plate and assembled -thereto. The entire diaphragm when ultimately assembled results in a significant reduc-tion in labor cost on the order oE fifty percent as compared to similar purpose constructions of the prior art, yet wi~hout adversely affecting the critical dimensional tolerances sought to be maintained.
It is therefore an object of the invention to provide a novel cons-truction for the diaphragm component of a - 2a -mah/ ~' multi-stage centrifugal compressor.
It is a further object of the invention to effect the foregoing object in a manner which results in substantial cost reduction as compared to otherwise similar purpose constructions utilized in -the prior art for constricted flow area relationships.
Brief Description of the Drawings . ... .
Fig. 1 is a longitudinal cross section of -the top half of a multi-stage centrifugal compressor in accordance herewith;
Fig. 2 is a fragmentary elevation of the diaphragm hereof as seen substantially along the lines 2-2 of Fig. l;
Fig. 3 is an enlarged and exploded sectional elevation of the diaphragm construction illustrated in Fig. l; and Fig. 4 is a fragmentary sectional view taken sub-stantially along the lines 4-4 of Fig. 3.
Referring now to the drawings, there is illustrated in FigO 1 a centrifugal compressor generally comprising a housing 10 defining a flow path extending from an inlet 12 communicating with a plurality of stages 14 in turn leading to an outlet 16. Comprising s-tages 14 are a plurality of spaced impellers 18 secured to a rotatable shaft 15 and arranged in series flow communication with each other with each stage discharging a hlgh velocity gas at its periphery. Energy transmitted to the gas creates a pressure rise as the flow velocity decreases in the diffuser section 20 immediately downstream of the impeller. From the diffuser, stationary guide vanes 22 turn the flow for proper entry into the succeeding impeller 18.
Betwee~ each impeller stage is a stationary diaphragm here designated 24, 26, 28, 30 and 32, as will be described, providing support for the stationary elements utilized between impellers such as the diffuser faces, guide vanes, return bend, labyrinths, etc. Associated with each diaphragm in the flow path entering the succeeding vane 22 about bulb section 23 is a clearance 33, the dimension of which is determinative of whether the specific diaphragm construction can be all cast as in the prior art or constructed in -the manner hereof~
As previously explained supra, a conventional all-cast construction of -the diaphragm can be u~ilized where clearance 33 to be encountered is on the order of one-half inch or greater. For purposes of illustration in Fig. 1, di.aphragms 24, 26, 28 and 32 are assumed -to have a clearance 33 thereat of greater -than one-half inch enabling them to be :Eabricated all cast in the manner of the prior art. Typically, these diaphragms are spli-t into semi-annular sections at their horizontal center ]ine which are later located with rabbet fits 34 and secured together via tie bolt 36.
Contrasting with those diaphragms, the clearance 33 i.mmediately preceding diaphragm 30 is assumed to be on the order of one-half inch or less such that the customary cast diaphragm construction of the remaining diaphragms become too cost prohibitive to be practical. Instead, diaphragm 30 utilizes a construction in accordance with the invention as will now be described with further reference to the remain:ing figures.
As specifically shown in Figs. 3 and 4, each semi-annular diaphragm construction thereof is comprised of return bend section 38 formed machined from plate and defining a horizontal split at center line 35 (Fig. 2). For joinder therewith is a vane section 22 cast per se in a conventional manner leaving the vanes freestanding on one side down to diameter 40. secause of the side exposure any need to core for effecting clearance 33 is eliminated while the clearance at diameter 40 being much larger than clearance 33 can be easily cored in a conventional manner. Joinder of vane section 22 with return bend section 38 is by means of a mutual. offset rail fit 42 at which the two are secured by screws 44 in order to render the installation permanent.
By the above description there is disclosed a novel construction for the diaphragm component of a multi-stage centrifugal compressor. The diaphragm is comprised of semi-annular sections, each of which is in turn comprised of a pair of separate sections that includes a cast vane section 22 joined by split screws and a rail fit to a mah/ '
By means of the invention, the low cost advantage of diaphragm casting for a multi-stage centrifugal compressor has been largely retained, even under conditions of close dimensional clearances in the flow path. Where the prior art constructions dictated substitution of the more expensive coring and/or machine-brazing approaches in order to meet dimensional requirements, it is possible by means hereof to construct the diaphragm in a manner largely preser~ing the 111'1l 1 use of a casting without the need for -the more costly coring.
By fabricating the diaphraym in this manner, the need for expensive coring in the constricted flow area is ellminated while still enabling the bulkier of the components, including -the vane section thereon, to be cas-t. The remain-ing return bend section can -then be machined from plate and assembled -thereto. The entire diaphragm when ultimately assembled results in a significant reduc-tion in labor cost on the order oE fifty percent as compared to similar purpose constructions of the prior art, yet wi~hout adversely affecting the critical dimensional tolerances sought to be maintained.
It is therefore an object of the invention to provide a novel cons-truction for the diaphragm component of a - 2a -mah/ ~' multi-stage centrifugal compressor.
It is a further object of the invention to effect the foregoing object in a manner which results in substantial cost reduction as compared to otherwise similar purpose constructions utilized in -the prior art for constricted flow area relationships.
Brief Description of the Drawings . ... .
Fig. 1 is a longitudinal cross section of -the top half of a multi-stage centrifugal compressor in accordance herewith;
Fig. 2 is a fragmentary elevation of the diaphragm hereof as seen substantially along the lines 2-2 of Fig. l;
Fig. 3 is an enlarged and exploded sectional elevation of the diaphragm construction illustrated in Fig. l; and Fig. 4 is a fragmentary sectional view taken sub-stantially along the lines 4-4 of Fig. 3.
Referring now to the drawings, there is illustrated in FigO 1 a centrifugal compressor generally comprising a housing 10 defining a flow path extending from an inlet 12 communicating with a plurality of stages 14 in turn leading to an outlet 16. Comprising s-tages 14 are a plurality of spaced impellers 18 secured to a rotatable shaft 15 and arranged in series flow communication with each other with each stage discharging a hlgh velocity gas at its periphery. Energy transmitted to the gas creates a pressure rise as the flow velocity decreases in the diffuser section 20 immediately downstream of the impeller. From the diffuser, stationary guide vanes 22 turn the flow for proper entry into the succeeding impeller 18.
Betwee~ each impeller stage is a stationary diaphragm here designated 24, 26, 28, 30 and 32, as will be described, providing support for the stationary elements utilized between impellers such as the diffuser faces, guide vanes, return bend, labyrinths, etc. Associated with each diaphragm in the flow path entering the succeeding vane 22 about bulb section 23 is a clearance 33, the dimension of which is determinative of whether the specific diaphragm construction can be all cast as in the prior art or constructed in -the manner hereof~
As previously explained supra, a conventional all-cast construction of -the diaphragm can be u~ilized where clearance 33 to be encountered is on the order of one-half inch or greater. For purposes of illustration in Fig. 1, di.aphragms 24, 26, 28 and 32 are assumed -to have a clearance 33 thereat of greater -than one-half inch enabling them to be :Eabricated all cast in the manner of the prior art. Typically, these diaphragms are spli-t into semi-annular sections at their horizontal center ]ine which are later located with rabbet fits 34 and secured together via tie bolt 36.
Contrasting with those diaphragms, the clearance 33 i.mmediately preceding diaphragm 30 is assumed to be on the order of one-half inch or less such that the customary cast diaphragm construction of the remaining diaphragms become too cost prohibitive to be practical. Instead, diaphragm 30 utilizes a construction in accordance with the invention as will now be described with further reference to the remain:ing figures.
As specifically shown in Figs. 3 and 4, each semi-annular diaphragm construction thereof is comprised of return bend section 38 formed machined from plate and defining a horizontal split at center line 35 (Fig. 2). For joinder therewith is a vane section 22 cast per se in a conventional manner leaving the vanes freestanding on one side down to diameter 40. secause of the side exposure any need to core for effecting clearance 33 is eliminated while the clearance at diameter 40 being much larger than clearance 33 can be easily cored in a conventional manner. Joinder of vane section 22 with return bend section 38 is by means of a mutual. offset rail fit 42 at which the two are secured by screws 44 in order to render the installation permanent.
By the above description there is disclosed a novel construction for the diaphragm component of a multi-stage centrifugal compressor. The diaphragm is comprised of semi-annular sections, each of which is in turn comprised of a pair of separate sections that includes a cast vane section 22 joined by split screws and a rail fit to a mah/ '
3~
machined return bend section 380 By this means, close flow clearance can be readily accommodated by more economical casting of at least the major component of the diaphragm as to eliminate need for the relatively uneconomical brazing fabrication i.n the manner of the prior art. Not only does this approach allow the vane section to be mostly cast, but it additionally affords incidental advantages such as allowing most of the flow path between vanes to be open for inspection or for finish grinding if necessary. ~oreover, the return bend section can be of any configuration which connects the diaphragms at the outside diameter that can even include portions of the preceding or following return bends or parts thereof or no return bend as in diaphragm 32 if desired. It should be apparent therefore that the construction hereof constitutes a significant advance in the art in solving a long-standing problem with constructing such diaphragms where minimum flow clearances have been encountered.
Since many changes could be made in the above construc-tion and many apparently widely different embodiments of this invention could be made without departing from the scope thereof, it is intended that all matter contained in the drawings and specification shall be interpreted as illustrative and not in a limiting sense.
machined return bend section 380 By this means, close flow clearance can be readily accommodated by more economical casting of at least the major component of the diaphragm as to eliminate need for the relatively uneconomical brazing fabrication i.n the manner of the prior art. Not only does this approach allow the vane section to be mostly cast, but it additionally affords incidental advantages such as allowing most of the flow path between vanes to be open for inspection or for finish grinding if necessary. ~oreover, the return bend section can be of any configuration which connects the diaphragms at the outside diameter that can even include portions of the preceding or following return bends or parts thereof or no return bend as in diaphragm 32 if desired. It should be apparent therefore that the construction hereof constitutes a significant advance in the art in solving a long-standing problem with constructing such diaphragms where minimum flow clearances have been encountered.
Since many changes could be made in the above construc-tion and many apparently widely different embodiments of this invention could be made without departing from the scope thereof, it is intended that all matter contained in the drawings and specification shall be interpreted as illustrative and not in a limiting sense.
Claims (6)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. In a multi-stage barrel type centrifugal compressor for compressing fluid flow including a vertically split housing defining a flow path from an inlet to an outlet, a multi-stage impeller in said flow path, an annular station-ary diaphragm encircling said multi-stage impeller in axially contiguous portions at each intermediate stage there-of for providing continuity of said flow path between successive of said stages and comprised of oppositely posi-tioned confronting sections which between at least one stage constrict the transverse f low dimension at a selected loca-tion of the flow path to less than about one-half inch and axially extending tie bolt means securing the axially conti-guous portions of said diaphragm, the improvement in which each annular portion of the diaphragm at said at least one stage is supported by said tie bolt means independent of said housing and is comprised of said confronting sections being joined interfitted together in a rail fit at a location along the flow path displaced from said constricted flow dimension with at least the larger of said confronting sec-tions being of a cast metal composition.
2. In a multi-stage compressor according to claim 1 in which the confronting sections of said improvement comprise a vane section and a return bend section with at least the vane section being of the cast metal composition.
3. In a multi-stage compressor according to claims 1 or 2 in which the component sections of said im-provement cooperate to define a transverse flow clearance therebetween of less than about one-half inch.
4. In a multi-stage compressor according to claim 1 in which the confronting sections are secured to-gether by fastener means.
5. In a multi-stage compressor according to claim 4 in which each diaphragm is constructed of matched fitting semi-annular portions and the confronting sections for each portion of the diaphragm of the improvement are of semi-annular extent.
6. In a multi-stage compressor according to claim 2 in which the confronting sections are secured to-gether by fastener means.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US16487380A | 1980-07-01 | 1980-07-01 | |
| US164,873 | 1980-07-01 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1189492A true CA1189492A (en) | 1985-06-25 |
Family
ID=22596451
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000379562A Expired CA1189492A (en) | 1980-07-01 | 1981-06-11 | Diaphragm construction for a multi-stage compressor |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JPS5746098A (en) |
| AU (1) | AU7192381A (en) |
| CA (1) | CA1189492A (en) |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5840319B2 (en) * | 1976-12-16 | 1983-09-05 | コメツト株式会社 | Inrush current suppression circuit |
| JPS54140301U (en) * | 1978-03-24 | 1979-09-29 | ||
| JPS6042019Y2 (en) * | 1981-09-07 | 1985-12-23 | 株式会社アマダ | Plate holding device in shearing machine |
-
1981
- 1981-06-11 CA CA000379562A patent/CA1189492A/en not_active Expired
- 1981-06-17 AU AU71923/81A patent/AU7192381A/en not_active Abandoned
- 1981-07-01 JP JP10313681A patent/JPS5746098A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| AU7192381A (en) | 1982-01-07 |
| JPS5746098A (en) | 1982-03-16 |
| JPH0116359B2 (en) | 1989-03-23 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |