Compressor Base And Intercoolers

Abstract

A base containing a pair of identical heat exchangers, demisters and separators has rigidly mounted thereon a cast multistage compressor casing provided with integral air inlet and discharge passages in direct communication with corresponding passages in the top wall of the base for providing the intercooling between stages. Fluid passes through the intercoolers by moving downwardly through the heat exchangers, downwardly through restricted nozzles and reversely upwardly for separating condensation, upwardly through the demisters and through central partition walls forming central manifold chambers. The liquid connections for the intercoolers may be uncoupled at one end for sliding the intercoolers off shelves from the opposite end. A telescopic resilient coupling between the casing inlet to the rotor and an inlet housing rigidly coupled to a fluid supply will prevent transmission of forces therebetween. The base further mounts the drive structure for the compressor and carries an oil sump below the drive structure.

Description

BACKGROUND OF THE INVENTION

Intercooler structure has heretofore been one of the largest components of a multistage compressor, which not only increases the cost of the compressor but of more importance increases the space required for mounting the compressor unit. The intercooler structure of the patent to Schierl, U.S. Pat. No. 3,001,692, issued Sept. 26, 1961, overcomes some of the problems in the prior art but still employs a rather large base in comparison to the size of the heat exchangers used and employs a considerable amount of piping between stages and waste space within the base.

The air connections for the Olmstead et al. patent, U.S. Pat. No. 2,849,960, issued Sept. 2, 1958, have advantages with respect to force transmittal, but present a rather complicated structure that must be assembled at the use location and does not provide any rigid support for the adjacent piping extending away from the pump.

CROSS-REFERENCE TO RELATED APPLICATIONS

The features of the invention of this application may be used in combination with the features of the inventions in applicant's following related applications of the same filing date and assignee as the present application, the disclosures of which are incorporated herein in their entirety by reference: "Compressor Barrel Assembly," Ser. No 44,446; "Compressor Power Recovery," Ser. No. 44,463; "Interchangeable Compressor Drive," Ser. No. 44,403; "Variable Capacity Compressor," Ser. No. 44,263.

BRIEF DESCRIPTION OF THE DRAWING

Further objects, features and advantages in the present invention will become more clear from the following detailed description of a preferred embodiment as shown in the attached drawing, in which:

FIG. 1 is a perspective view of a multistage centrifugal compressor;

FIG. 2 is a schematic flow diagram showing the relationship of the compressor stages and intercoolers;

FIG. 3 is a partial cross section side elevation view, with the cross sections being taken in a vertical plane passing through the axes of rotation of the compressor rotor and drive assembly;

FIG. 4 is a partial cross section and exploded view of a portion of the structure as shown in FIG. 1; and

FIG. 5 is a cross-sectional view taken on line 5--5 in FIG. 3 showing the air discharge manifold of the intercoolers.

DETAILED DESCRIPTION OF THE DRAWING

The base 1 as shown in FIG. 1 has mounted rigidly thereon an fluid inlet housing 2 by means of a plurality of bolts (not shown) passing through bolt holes 3, a one-piece cast compressor casing 4 by means of a plurality of bolts 5, a gear housing 6 by means of a plurality of bolts 7, an electric drive motor 8 by means of resilient pads 9, and a control panel 10 by any conventional means.

The inlet housing 2 is provided with an annular flange 11 provided with a plurality of peripherally arranged holes 12 for rigidly securing thereto an inlet fluid pipe when assembling the compressor at the use location. An upwardly extending integral mounting arm 13 is provided on the flange 11 for mounting thereto by means of bolts, or the like, a support bracket 14 that carries the diaphragm control mechanism 15 of an inlet valve member 16, with the interposition of a suitable linkage 17. The inlet valve mechanism 15, 16, 17 is conventional per se for throttling the inlet fluid on partial load and for density control in a known manner. The diaphragm control is provided with a pressure feedback tube 18 for this purpose. The multistage impeller rotor and fluid guide structure is contained within the one-piece cast casing 4, which casing is provided with an axially through cylindrical bore 19, a downwardly facing planar surface 20 engaging the correspondingly planar upper surface of the top wall 21 of the base 1, and with an upwardly extending boss 22 that is bored for fluid communication with the outlet of the last compressor stage. As will be described later, a resilient coupling for vibration and load isolation is provided between the fluid inlet housing 2 and the compressor casing 4.

The drive assembly for the compressor may be of any type, but preferably employs the electric motor 8 that drives a gearset within the gear housing 6. Particularly, the drive structure may be of the type mentioned in one of applicant's previously identified applications wherein the structure is set forth in detail.

Welded steel fabrication is used for constructing the base 1, preferably from stock sheet and plate steel. The front wall 23 is provided with oppositely opening doors 24, which lead to a control and auxiliary component compartment having therein the inlet and outlet water couplings for the intercoolers. The supply 25 and outlet 26 water pipes for the intercoolers extend permanently through the sidewall 27 and are provided at their outer ends with suitable couplings to be connected during installation at the site of use.

The basic fluid flow for the compressor is shown in FIG. 2 wherein the impeller of a first stage 28 passes fluid downwardly through a first intercooler 29. Thereafter, the fluid passes through the second stage impeller 30, which directs it downwardly through the second intercooler 31. Finally, the fluid passes upwardly and through the third stage impeller 32 for discharge to the point of use. The impellers 28, 32, 30 form an integral rotor drivingly connected with a spur helical pinion gear 33 that is driven by means of a drive helical gear 34 mounted on a parallel axis gear drive input shaft 35.

The inlet connection is shown in more detail in FIG. 3. A cylindrical mounting portion 36 of the inlet housing 2 is telescopically received over a cylindrical mounting portion 37 with the interposition of an O-ring 38. From the drawing, it is seen that the adjacent cylindrical surfaces of mounting portions 36, 37 are radially spaced from each other so that the O-ring 38 provides the only engaging connection between the inlet housing 2 and the compressor casing 4, while sealing these structures. Thus, the inlet housing 2 is independently supported on the base 1 to prevent transmittal of inlet housing vibration, canting, axial movement, radial movement and rotational movement to the compressor casing 4. Thus, the complete compressor may be supplied to a user and the user may rigidly couple his inlet fluid pipes directly to the inlet housing 2, without fear that forces relating to the coupling and inlet pipes will be transmitted to the compressor casing. Further, the stresses due to tightening of the connections between the inlet casing and fluid supply pipes will not be transferred to the compressor casing.

The removable barrel structure of the compressor includes separate shrouds, diffusers, and annular fluid guide elements all received in a stacked relationship within the cylindrical bore 19 of the one-piece compressor casing 4. The compressor casing 4 is provided with integrally cast passages extending between the barrel assembly and the base 1. Particularly, a first passage 39 extends between the bore 19 and the planar surface 20 to conduct fluid from the discharge of the first stage, second passage 40 extends from the bore 19 to the planar surface 20 to conduct the fluid into the third-stage inlet, third passage 41 extends from the bore 19 to the planar surface 20 to conduct fluid discharged from the second stage and fourth passage 42 extends from the bore 19 to the planar surface 20 to conduct fluid to the inlet of the second stage. The base 1 is provided with a top wall 21, opposed sidewalls 27 and 43, opposed front and back walls 23 and 44, and a bottom wall 45, which together form a substantially closed main chamber containing the intercooler structure. The top wall 21 is provided with a plurality of passages, also shown in FIG. 4, extending between the passages 39-42 and the intercooler main chamber. Particularly, the top plate 21 is provided with holes 46 that align with passages 39, holes 47 that align with passage 42, hole 48 that aligns with passage 40 and hole 49 that aligns with passage 41.

Two parallel partition walls 50, which are parallel to the walls 27, 43, extend completely from the top wall 21 to the bottom wall 45 and extend from the front wall 23 to the backwall 44 to form a central manifold chamber 51. Additional partition walls 52 subdivide the manifold chamber into three aligned subchambers, with the outside subchambers 53 being in fluid communication between the holes 47 in the top wall and correspondingly aligned holes in the left-hand partition wall 50, and with the inside subchamber 54 being in fluid communication between the hole 48 and a hole 55 in the right-hand partition wall 50 as shown in FIG. 3. In this manner, the main intercooler chamber is further divided into a first intercooler chamber 55 to the left of the partition walls 50 and a second intercooler chamber 56 to the right of the partition walls 50, as seen in FIG. 3. Identical and interchangeable parallel tube fluid heat exchangers 57 are mounted on shelves 58 within their respective intercooler chambers 55, 56 so that they may be horizontally slid into and out of the base 1 after the releasably secure back wall 44 is removed. For this purpose, the pipes 25, 26 are provided with releasable couplings 59 for uncoupling the heat exchangers, without affecting the location of the pipes 25, 26.

It is seen from FIG. 3, that fluid discharged respectively from the first stage and the second stage will pass through passages 39, 41 and holes 46, 49 downwardly into intercooler chambers 55, 56 to pass through their corresponding heat exchangers 57. Thereafter, the thus cooled fluid will be directed by baffle plates 60 through vertically extending restricted nozzle-type passages 61 where the flow of fluid will approach sonic velocity. The high-speed fluid then passes through a sharp acute angle and upwardly through demisters 62. Thus, it is seen that the baffles 60 formed in the nozzle-type passages 61 constitute separators that will take the cooled fluid from the heat exchangers having condensed droplets therein, accelerate this cooled fluid and substantially reverse the flow of the accelerated cooled fluid to separate the condensate. Further, moisture will be removed from this separated fluid by means of demister 62. Thereafter, the relatively dry fluid will pass through respective holes in the partition walls 50 so that the fluid from the intercooler chamber 55 will pass into the submanifold chambers 53 and fluid from the intercooler 56 will pass into the submanifold chamber 54. It is noted that the left-hand passage 61 is substantially larger than the right-hand passage 61 as shown in FIG. 3, which difference is proportional to the difference in volume of fluid handled by the two intercoolers due to compression. For this same reason, two submanifold chambers 53 are provided for returning fluid to the second stage, while only one submanifold chamber is provided for returning fluid to the third stage.

Beneath the drive assembly 8, 6, the base 1 is provided with an oil sump 63, which is in direct communication with the interior of the gear housing 6.

From the above, it is seen that the compressor base of the present invention separately and rigidly mounts a rigid compressor casing and a rigid fluid inlet casing, and provides a telescopic coupling therebetween having only a flexible interengagement by means of the O-ring 38. With this coupling, the user's rigid fluid inlet pipes may be rigidly connected directly to the fluid inlet casing 2 for support thereof, without fear that the stresses produced by the rigid supply coupling will be transmitted to the compressor casing 4. Also, any vibrations, thermal expansion, settling, misalignment, etc. associated with the user's fluid supply pipes will be transmitted only to the heavy rigid base and not transmitted directly to the compressor casing. Further, this O-ring seal 38 and flexible coupling will accommodate misalignment and tolerances as between the casings 2 and 4, as well as preventing force transmittal therebetween because of the considerable radial spacing between the telescoping cylindrical portions 36, 37. Further, the inlet casing may be advantageously used for a conventional type of inlet valve, without fear that forces associated with the inlet valve will be transmitted to the compressor casing.

The compressor casing is of a one-piece cast construction with integral fluid passages between stages communicating between each stage and intercoolers within the base, respectively, so that no bulky, costly and cumbersome external piping connections are required. For this purpose, the base has a top compressor supporting wall that is provided with integral passages aligned respectively in fluid communication with the compressor casing integral passages so that fluid is conducted from the first and second stages downwardly into the intercooler chambers and upwardly from the intercooler chambers into the second and third stages.

The base is further of a compact construction in that it requires very little extra room over that of the plan view dimensions associated with the compressor casing and inlet fluid casing, with respect to its enclosure for housing intercoolers, centrifugal separators, and demisters. The intercoolers are identical and the demisters are identical to provide for interchangeability and inexpensive manufacture. Also, the separators are formed by baffles that are identical although assembled in mirror image fashion. The fluid flows downwardly through the intercoolers through a restricted passage formed by the separator baffles so that the cooled fluid approaches or reaches sonic velocity before it is sharply and reversely guided upwardly through the demisters, so that during this reversal, droplets of condensate will be discharged downwardly where they will be collected and removed if desired. The fluid moving upwardly through demisters is further directed upwardly through submanifold chambers located centrally between the two intercooler chambers for discharge through the top wall of the base. Construction of the base is rigid and relatively inexpensive in that it is of welded steel fabrication employing only planar sheets and plates, with the partition walls forming the submanifold chambers considerably contributing to the rigidity of the entire structure by providing cross bracing.

The portion of the base under the drive mechanism, particularly an electric motor and gear train, is of relatively shallow construction due to the greater height of these components and forms a sump for the oil lubrication system. Preferably this sump is in direct communication with the gear housing.

The intercoolers are mounted within their respective intercooler chambers by means of shelves so that they may be slid horizontally in one direction out of the base, after the removal of the adjacent releasably mounted wall. The wall opposite from the releasably mounted wall is provided with access means so that rigid cooling liquid supply and exhaust pipes may be quickly coupled and uncoupled from the intercoolers. In a like manner, the demisters are mounted on respective shelves to be horizontally slid out of their respective intercooler chambers in the same direction as the heat exchangers, for purposes of repair, replacement or the like.

While a preferred embodiment of the present invention has been specifically described with respect to specific advantageous features, it is to be realized that the invention, in its broader aspects, includes further modifications, embodiments and variations.

Claims

What is claimed is:

1. A multistage compressor, comprising: a base; a compressor rotor having at least two impellers; casing means rigidly secured on said base and rotatably supporting said compressor rotor for providing at least two compression stages, said casing means having an integral fluid outlet for the first stage and an integral fluid inlet for the second stage; said base including an upper wall, sidewalls, and a lower wall forming therebetween a substantially closed intercooler chamber; and said upper wall having an integral chamber inlet in fluid communication directly with said first-stage fluid outlet, and an integral chamber outlet in direct fluid communication with said second-stage fluid inlet.

2. The compressor of claim 1, wherein said casing means includes a one-piece cast casing having an axially through cylinder bore receiving concentrically therein said compressor rotor and a downwardly facing horizontally planar surface; said casing means inlets and outlets extending between said bore and said planar surface, with their respective ends opening upwardly and downwardly; said base upper wall having an upwardly facing substantially horizontally planar surface engaging the entire casing planar surface.

3. The compressor of claim 1, including liquid gas heat exchanger means mounted in said intercooler chamber in fluid communication between said chamber fluid inlet and said chamber fluid outlet; and chamber partition means forming a constricted passage for the fluid downstream of said heat exchanger means for passing the fluid downwardly and sharply reversing the fluid upwardly to discharge condensed liquid therefrom.

4. The compressor of claim 3, including demister means mounted in said intercooler chamber downstream of said separator.

5. The compressor of claim 1, wherein said compressor rotor has three impellers and said casing means provides three compression stages; said casing means further has an integral fluid outlet for the second stage and an integral fluid inlet for the third stage; said upper wall further has an integral chamber fluid inlet in direct fluid communication with said third-stage fluid inlet; and including two separate heat exchangers in said intercooler chamber, means mounting one of said heat exchangers fluid interposed between said first-stage fluid outlet and said second-stage fluid inlet, and the other of said heat exchangers fluid interposed between said second-stage fluid outlet and said third-stage fluid inlet.

6. The compressor of claim 5, including partition wall means in said base forming three aligned manifold subchambers, with the two outside manifold subchambers being in fluid communication with said second-stage fluid inlet and the middle manifold subchamber being in fluid communication with said third-stage inlet.

7. The compressor of claim 5, including generally vertical partition wall means in said base forming at least two manifolds extending vertically for substantially the entire height of said intercooler chamber and being respectively in direct fluid communication through said upper wall with said second-stage fluid inlet and said third-stage fluid inlet.

8. The compressor of claim 7, including said partition wall means further dividing said intercooler chamber into a separate first intercooler subchamber on one side of said manifolds and a separate second intercooler subchamber on the other side of said manifolds, with said first-stage fluid outlet discharging downwardly directly into said first intercooler subchamber and said second-stage fluid outlet discharging downwardly directly into said second intercooler subchamber; and passage means interconnecting respective intercooler subchambers and manifolds.

9. The compressor of claim 8, wherein said heat exchangers are identical; said base having shelf means mounting each of said heat exchangers for relative horizontal sliding in the same direction for removal and assembly; said base having one sidewall being perpendicular to said direction and being removable to provide access for assembly and withdrawal of said heat exchangers; rigid inlet and outlet liquid conduits on the other side of said heat exchangers opposite from said one sidewall having releasable coupling means fluid connecting them respectively to said heat exchangers; and said base having removable wall means on said other side for providing access to said releasable couplings.

10. The compressor of claim 9, including demister means operatively mounted in each of said intercooler subchambers respectively downstream from said heat exchangers; and fluid guide means for respectively directing fluid from said heat exchangers downwardly and then reversely upwardly through said demister means.

11. The compressor of claim 10, wherein said fluid guide means each have a narrow vertically extending nozzle passage for accelerating and directing the fluid downwardly closely adjacent the bottom of each intercooler subchamber and then upwardly through said demister means to constitute condensate separators.

12. The compressor of claim 10, wherein each of said heat exchangers is mounted above the corresponding interconnecting passage means and each of said demister means is mounted below the corresponding interconnecting passage means.