DE2158518A1 - Multi-stage centrifugal pump - Google Patents

Description

Multi-stage centrifugal pump

The invention relates generally to a multistage centrifugal pump which firstly has a predictably homogeneous and substantially crack-free housing, secondly has a construction which enables easy and inexpensive replacement of the pump parts which are subject to erosion and wear and which thirdly has means which enable it to finally process the impeller arrangement of the pump when the impellers are sumped onto the pump shaft and the arrangement is dynamically balanced before it is installed in the pump the conveyance of dangerous and / or harmful liquids «» Examples of such areas of application are boiler feeding, refining and chemical processes and power stations © ₀

Pumps of this type currently in use are general provided with a split housing made of cast material, the guide spirals or diffusers in

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are cast in one piece into the housing. It is difficult to form castings that are predictably homogeneous and free of internal cracks or defects ₀ For critical pump applications, it is necessary to examine such castings very carefully, generally with radiographic methods, with housings with voids or cracks or a repair which is included as an additional repair phase in the manufacturing process of the pump, or have to be scrapped

A more recent method consists in designing the split housing as a simpler cast piece, with the guide spirals or diffusers arranged between the steps being molded separately ₀ In this arrangement, the impeller arrangement is first assembled, then dynamically balanced, dismantled, with the guide spirals arranged between the impellers again assembled and finally the reassembled impeller assembly together with the guide spirals arranged between the stages is installed in the pump housing _{or the like}

By this method the most, the Gußstüoken inherent problems remain with the rather complicated process of assembling, balancing, disassembly and reassembly of the impeller assembly with the conducting spirals before they built into the pump; £ the "off ₀

Examples of present and past cons ^? 21 ^? I; isa * ϊγ pumps of this type are described in US Patentsclifif-fceu jt _o 3,375,789, 2,072,033, 3,466,724, 2,634,685, 1,941,442,

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1 998 754, 2 281 650, 888 192, 2 219 098, 1 392 090,

1 525 756, 3 229 642, 3 188 968, 3 131 877, 2 771,207,

2 668 502, 2 601 828, 2 4? 0 137, 2 374 122, 2 368 962, 2 331 299, 2 294 143 and 2 286 522.

Of these patents, Patents Nos. 3,229,642, 1,941,442, 1,998,754 and 2,286,522 show constructions "which have features which are somewhat similar to features of the present invention own o. ^

It is a primary object of this invention to provide a pump which includes components that permit a minimum of radiographic inspection and requires a minimum of repair work on these components to achieve an acceptable standard of quality during manufacture of the pump

Another object of the invention is to provide a pump, having the components and assemblies of consistently higher quality than that of comparable components of earlier pump _α

Yet another object of the invention is to provide a To provide a pump that has components that can be manufactured at a much lower cost as comparable components of previously known pumps ο

Another object of this invention is to provide a su pumps, in which a lower standard time is required a supply of blanks FTTR the subsequent finishing processing and to eahaffen ₀

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Another object of the invention is to provide a pump which requires a smaller inventory of replaceable parts.

Another important object of the invention is ee, a To create a pump which can be easily and effortlessly repaired and overhauled with a minimum of tools and / or Spessialeinriohtungen / grounded while it remains on site.

These and other tasks and benefits are realized by the multistage centrifugal pump and process eu of their manufacture as disclosed herein · The Invention is characterized by a forged and shaped pump housing with a built-in, generally round and elongated pump chamber, through an impeller unit with a number of impellers, which are mounted on a rotatable shaft in no, and which are arranged in the housing within this chamber is and duroh a large number of two-step spiral spirals, which are fitted around the impeller assembly and between the impellers and which are inside and within the housing Chamber are attached, the impeller unit is dynamically balanced after its completion.

, johand the following description of one in the drawing illustrated embodiment B of the invention this is explained in more detail · Bs seigern

Pig. 1 a side view of an invention

appropriate pump ready for operation with a power source and mounted on a gearbox,

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Pig. 2 a long time through the pumping

the housing, the seals and a skin of the bearings of the pump shaft «

3 shows an enlarged longitudinal section

duroh a rope of the pump, which is to the left of the Hitte of in Pigο pump housing shown is located,

Pigο 4 a cross section according to the line ä

4-4 in Pig. 3,

Pig · 5 a cross-section along the line

5-5 in Pig 3,

Pig »6 a cross section along the line

6-6 in Pig. 2,

Pig · 7 a cross exit after the line

7-7 in Pig. 2 and

Pig «8 a cross-section along the line

8-8 in Pigo 2 »'

Referring to Pig · 1, there is shown a pump assembly, indicated generally at 10, which includes a pomp 12 which Is connected via a threatening coupling 14 to a gear unit, which in turn is connected to a power source 20 via a further rotary coupling 18 «,

The power source 20 is shown as an electric motor, for example, for 305 hp at 3600 revolutions per Out of the open 1st. The one shown in the drawing

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For example, the pump can have a capacity of 550 liters (Water) at a delivery pressure of 183 kg / om with a have a pressure of 1.05 kg / om »if ßie through, aie Gear unit 16 with 12,500 revolutions per minute is driven. Ee is the gear ratio of the gear 16 is chosen so that the output of 3 Revolutions per minute of the power source 20 is translated to the input of 12,500 revolutions per minute of the pump 12. In certain areas of application, the Power source 20 could be a gas or steam turbine, for example, "in which case the gear unit 16 will have a different gear ratio depending on the requirements."

The pump 12 is provided with bearing feet 30 on As shown, the gear unit 16 and the power source 20 are also attached to the base frame 24. The base frame 24 is on one The foundation 28 is supported and rests on a set 26 Lime cast ·.

The pump 12 comprises a housing 32 having a lower housing part 34 and an upper housing part 36. The lower housing part 34 is provided with a fluid outlet 38 which terminates in a pipe flange 40 or other suitable connecting element, and with a fluid inlet 42 which also in a pipe flange 44 or other suitable connecting means (Fig, 2, 6, 7, and ii) ends "the pump 12 also has a pump shaft 46 which carries a wheel group being described later ₀ the shaft 46 is axially supported and driven at its end a bearing assembly 48 is aligned with bolts 50 on the lower housing.

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part 34 is attached by means of a carrier 52 ", BaB opposite end of shaft 46 is supported and aligned both axially and longitudinally by means of a bearing arrangement 54 »which is secured by bolts 56 on the lower Housing part 34 attached by means of a carrier 58 iat.

A Teillängssohnitt the pump 12 1st ₀ in FIG 2, respectively. As can be seen there, the lower housing part 34 is shown

and the upper housing part 36 formed so that they

form a housing bore 60 »when they are joined together |

The housing parts 34 and 36 (Fig. 6) are in one predetermined alignment by means of at least two

Taper pins 62 assembled, one of which is shown

is · The housing parts 34 and 36 are in their zu8amoi <ftn ~ & built location by a number of head screws 64, one of which is shown, or by similar means " like bolts and nuts, held together · The ends of the

Bore 60 (Fig. 2) are through retaining caps 66 and 66

closed · The retaining caps 66 and 68 are in their assembled with the housing plates 34 and 36

State through a number of bolts and nuts 70

held. The bore 60 is opposite the exterior of the

Pump 12 duroh sealing rings IZ sealed, the "

the retaining caps 66 and 68 are arranged and between these caps and the housing parts 34 and 36 lie, as well as by means of a suitable, not shown

Seal or by means of Diohtungsflächen between the Parts 34 and 36.

shown, the impeller shaft 46 is in its axial Position supported within bore 60 by bearings 48 and 54. Rotatable mechanical fluid diaphragm assemblies 74 and 76 are within retaining caps 66

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and 68 Iind arranged around the shaft 46, abzudlohten about the rotatable within bore 60 of shaft 46 uer "The Dlohtungsanordnungen 74 and 76 pietlB 12 may be suitable type of currently commercially available and for the intended use of the pump. The Puiapenwelle 46 forms a rotatable bearing for an impeller group 78, which consists of a number of pump impellers 80 to 90, which are mounted on the shaft 46.

A suction-side guide element is connected to the inlet 42 and the impeller 80 within the bore 60 92 arranged. Between the wheels 80 and ü2, 82 and 84 »86 and 88, as well as 88 and 90 are each segmented guide spirals 94» 96, 98 and 100 in the Bore 60 attached, which will be described in more detail later · An intermediate guide element 102 is in the bore 60 disposed in fluid communication with an intermediate suction inlet 104 and an impeller 90. A sealing damming element 106 is in the bore 60 between attached to the guide element 104 and the holding dowel 66 »between the running wheels 84 and 86 is within the Bore 60 a subdivided into segments pump stage part 108 is arranged, which is explained in more detail below.

The guide element 92 and the guide spiral 94 form a pump chamber 110 of the first stage within the bore 60 · The guide spirals 94 and 96 enclose a second one Stage forming chamber 112. The guide spirals 96 and the Step dividers 108 delimit a chamber 114 forming a third step. O The intermediate element 102 and the guide spiral 100 form a chamber 116 between them fourth stage. A chamber 118 as the fifth stage is

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limited by the Leitapiralen 100 and 98, while one sixth stage duroh that of the spiral guide 98 and the Step divider 108 is formed into closed chamber 120

The flow of fluid between the chamber 114 of the third stage and the chamber 116 of the fourth stage v / ird is made possible by a transition 122 which is attached to the upper housing part 36 and emerges from a conical bore 124 communicating with the chamber 114 forming the third stage to the intermediate inlet 104 _o The line 122 is connected to the housing part 36, for example by fillet welds, between the chamber 120 of the first stage and the flow top outlet 38 there is a connection via a flow medium outlet line 126, which on the one hand to the flange 40 and on the other hand to the lower housing part 34 is connected via a conical outlet bore 128, which is formed in the lower part of the housing 34 and opens into the chamber 120, as can be seen, a larger or smaller number of pump stages can be provided if desired.

Split retaining rings 130 (? Lg. 3) are on the shaft arranged and all running wheels »such as 2 · Bo 82 and 84, assigned to these impellers in their location on the To position the shaft in the longitudinal direction. Keys are in mutually associated longitudinal grooves in the shaft 46 and the impellers arranged to the impellers in their angular position on the y / elle

Within the housing 32, around the v / el 46 and in communication with the fluid inlet 42, there is an iiMUgti ei ti geti LojLtKileiiiönt 9i '^;!'■> * u * u foj arranged

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This guide element 92 consists of two disk-shaped ones Parts in the middle of a semi-syllable wall and webs 136 spaced concentrically from one another are arranged to one another and connected to one another. As shown, the guide element 92 with the holding cover 68 and the bore 60 together form a seal chamber 138 in which the fluid pressure is the same remains as in a suction chamber 140, which is within the Guide element 92 is formed »An annular flange, which protrudes from the guide element 92, fits into a / associated recess formed in the bore 60 to the suction chamber 140 opposite the Seal chamber 110 of the first stage and around the LeJBleiaent 92 longitudinally within the bore 60 · The purpose of the webs 136 is primarily to provide rotation or turbulence üea prevent fluid within the suction chamber 140 when the pump 12 is in operation.

As mentioned above (FIGS. 2 and 1) ₉ , the disk-shaped intermediate guide element 102 and the disk-shaped damming element 106 are attached. The guiding element 102 is equipped with a generally semicircular wall 142 and a web 144. The guiding element 102 and the damming element 106 form one Intermediate suction chamber 146 within the bore 60 ₀ The damming element 106 and the retaining plug 66 form a “wide Diohtungskammer 148 within the bore 60 _o Ring-shaped flanges protruding from the guide element 102 and from the damming element 106 fit in them associated recesses in the bore 60 _f around these elements within of the housing and a seal against a flow ciiftyf-rs Hl'η .enters and dom uehauns:.; u α-αϊίαίί ^ 4- -,

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The Diohtungskammern 13b and HS (Fig. 2) protrude in the upper housing part 36 formed channels 150 and and a flow compensation line 154t in these channels are welded in, for example by fillet welds, in connection with one another. Inside the damming element 106 and around the v; el 46 there is a sealing cover 156 arranged »Between the shaft 46 and the sleeve 156 a sealing ring is arranged» Kin divided Retaining ring and a feather key are between the A / elle and the sleeve 156 to position the sleeve

through ύ

kidney «like this / those assigned to the wheels

Hinge and parallel keys are done «In the construction described, the twisted wires 74 and 76 In in the same way only exposed to the suction pressure of the fluid entering the pump 12, namely without RüokBioht on the increased Sbufenförderdruck within the pump.

As can be seen, an annular, Tom step divider 108 protruding flange fits into a corresponding, Recess formed in the bore 60 in order to position the step plate in the bore 60 in the longitudinal direction and a fluid seal between the stage | divider 108 and the bore 60 to form

In Pigο 3 and 4, each of the wheels is like them represented by the impellers 82 and 84, provided with a hub 158 which is sumped onto the shaft 46 and duroh a ring 130 and a feather key 132 is held in the manner described above · The inner durometer of the hub for the running wheels 82 and 88 is slightly smaller than that of the impellers and 86, and the diameter of the have of the impellers

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and 90 let slightly less than that of impellers 84 and 86ο The purpose of these Durohmesserdlfferenss is to facilitate the assembly of impeller group 78. The shaft 46 achieves a corresponding reduction in the diameter of the diameter at the corresponding hub positions. These differences in diameter can be small, for example in the range of 0.025 to 0.125 om formed from elongated and generally circular Y / ends connected by spiral vanes 164. The I 158 against erstreokt fled in the axial Riohtung from the outflow port 160 away an annular intake tube 166 · Each hub 158 and each suction funnel 166 to be closely but without touching _t, in an associated, adjacent bore added, as shown in the drawing and is described later «

As can be seen in Pig «2 with reference to FIG is, the Diohtungsbüohse 156 is very tight from the Bore of the stowage element 106 is enclosed and each impeller hub 158 and impeller triohter 166 becomes similar closely received by the associated bore of an adjacently mounted element · Such a tight clearance is provided to the flow of the pressurized Fluid from any particular chamber to the to obstruct adjacent chamber ο As can be seen from Figo 3, each of these has associated holes an alternating series of ribs and grooves, indicated as a whole by 168 and the purpose of which is to form a series of successive annular mouths, the successive

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Cause a drop in pressure or a decrease in the amount of fluid flowing through it * A huge one Design serves to further limit the flow under the influence of pressure between adjacent chambers to to a value that allows an acceptable pumping efficiency «

The impellers 80, 82, and 84 are in construction

generally the same except that the hub of the impeller 64 is threaded to connect with the impeller 86, which is provided with a corresponding mating thread, to enable a screw connection 170. she Impellers 86, 88 and 90 form in their construction generally the mirror images of the wheels 96, 94 and 92, with the exception of the deviation required for the screw connection 170 »The outflow volumes of the Impellers 84 and 86 have a slightly different shape from the remaining impellers a radial outflow compared to the longitudinal outflow of the between the stages Wheels see below Wheels make this general easier Type are generally in trade and there is no need for | half another description.

As a peculiarity of multi-stage pumps of this type, the flow causes fluid to escape from the impellers 80 and an axial force or thrust away from the driven end of shaft 46 as the fluid exits from the impellers 90 and 88 an opposite and essentially equally large Azialeohub against the driven end of the shaft causes the axial stroke, as it may have been generated by impeller 84, is due to the opposite stroke of the impeller 88

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The threaded connection 170, in addition to facilitating the assembly of the impellers 84 and 86 on the shaft 46, creates a longitudinal alignment between the connected impellers in relation to the solid 46, and also relieves any thrust generated by those impellers to any resulting surface inconvenience as it does can be brought about by fluid pressure on the annular surface of the Diohtungsbüohee 136 uew ₀ , is "absorbed" by pressure included in the bearing arrangement 54

As can be seen from Fig. 3, the stage divider is divided into several symmetrically subdivided segments which, after their installation and the balancing of the impeller group 78, are inserted between and around the impellers 84 and 86 and which are secured by a fastening element, e.g. a head screw, a tapered pin or the like, in their assembled state are kept "

Pig _e 2 and 3 show that the guide spirals 94 and 94 are identical in their construction and are interchangeable with one another. The guide spirals 98 and 100 are designed as mirror images of the guide spirals 94 and 96 “Ss therefore only the guide spiral 96 is described, and“ was based on the Pig o 3 and 5. The guide spiral 96 has complementary segments 174 and 176, which are built in its building State by which a head screw 178 is held _o In the assembled state, the guide spiral 96 forms a radially extending flange 180 "which is fitted into a corresponding radial recess located in the bore 60" Lower housing part 34 in front of the pocket formed in order to precisely guide the spiral guide 96 when assembling the pump 12

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Position housing 32., In assembled condition The guide spiral 96 forms flow channels 184 and 186, some of which are delimited by a lip 186 is formed on a segment 174, which terminates in a web 190, der.an the hips of the ribs and billets

unci

Row 168 ends, / partly through a similar hip old web 194 on a segment 176.

Further details of construction can of Figure "with the aid of Figure 6 _0, are removed. 7 and 8 You Fig. 6 shows how the inflow channel 42 in several f

Channels is divided to a substantially uniform entry of the fluid into the suction chamber 140 to create · From Pig «7 the division of the channel 104 into several channels can be seen, which serves to a substantially uniform entry of the fluid in the double suction chamber 146 to ensure Auselaßbohrungen 124 and 128 of those shown in FIG Art are conical in shape, or more precisely, widening and increasing in cross-sectional area, to recover kinetic energy from the fluids to be pumped. Fig. 8 shows also a fluid channel 126 which is in a g

gentle curvature with a large radius and the Planoh 40 with the lower housing part 34 and there with the outflow opening 128 connects "The flange 40 is carried by the housing 32 via a holder 196 ·

The housing 32 is created by using two identical metal billets or parts are forged, or by adding a single block of metal or a single metal part forged accordingly and then in the ..output parts for the lower housing part 34 and the upper

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Housing part 36 is divided «Bex the term" forging ", as it is used below, is intended to describe the deformation of a metal part by the application of considerable pressure or force ₉ whereby the resulting part is homogeneous in a structure and free of cracks , Faults and internal flaws is. Pas lower housing part 34 and the upper housing part 36 are then formed; the term "shapes" the machining, grinding and / or welding, etc. is meant to _0, the ER ■ _f is conducive to the holes "recesses and the other erforderHohen surfaces to as shown in the drawing. The inlet, outlet, and remainder passages are shaped as shown. Pie shaft 46 is formed from a rod blank. Pie Iial connectors 66 and 68 can be made by forging or casting and then shaping into the structure shown in the drawing. The internal parts of the pump 12 are not subjected to critical pressures and are not subject to fluid tightness requirements and are considered consumables "to be replaced" when they are too worn by erosion under the influence of the fluids. These components, such as baffles, impellers, stage divider conducting spirals and baffle plates may be prepared as a simple castings, which corresponds then "speaking their shape shown are formed _o v / hile the preparation are located, the impellers in series or in succession on the shaft 46, after each impeller has been heated, positioning each impeller with its associated mating ring and barrel spring o First impellers 84 and 86 are assembled, then the remaining impellers are successively assembled, o Each impeller

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2) 58578

ο I can then cool down and shrink it firmly onto the shaft. After the assembly of the impeller group, it is dynamically selected in a rotating manner , as is the case with the usual selection processes seals and Lagervorriohtungen at each end of the shaft 46 are added ₀ the resulting assembly is placed in the lower housing part 54, etc. and then the entire pump 12 is in the position shown susaiomengebaut type ₀

Although only a preferred embodiment of the invention has been described and shown, it can be seen that many other designs and designs are possible, without the underlying » to deviate ο

Expectations:

-IB-

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Claims (4)

21S8518 - 18 -patent claims t 1. Multi-stage centrifugal pump, characterized by a forged and shaped pump housing (32 »34» 36) with a generally round and elongated pump chamber (60) formed therein, by an impeller unit (78) with a plurality of impellers (80 to 90) ) »Which are mounted in series on a rotatable shaft and which is arranged in the housing within this chamber and by a plurality of τοη two-stage guide spirals (94» 96 »98» 10O) ₁ which are adapted to the impeller unit and without the impellers and which are mounted within the housing and in this chamber o 2 ο centrifugal pump according to claim 1 »characterized in that in the impeller unit (78) the impellers (80 to 90) are shrunk onto the rotatable shaft (46) ο 3 ο centrifugal pump naoh one of claims 1 or 2, characterized in that the guide spirals (94 »96, 98, 100) consist of complementary segments (174 »176)» 4. centrifugal pump naoh one of claims 1 to 3, characterized in that the impeller unit is formed so that it is rotating after its assembly is dynamically auewuohtable «, 5 · Centrifugal pump according to one of Claims 1 to 4, characterized in that holding covers (66, 68) are installed in the pump housing, which cover the ends of the shaft (46) and lock this chamber ο - 19 - 2Uä827 / 0B58 6o centrifugal characterized labeled in claim 5 """characterized in that seals (74, 76) are mounted in the holder covers and the shaft surrounded, and in that the fluid pressure compensating means (138, 140 _f 154" 148) are provided, the pressure differential which equalize across these seals " 7 ο centrifugal pump according to one of claims 1 to 6, characterized in that the housing (32), the impeller unit (78) and the guide spirals (94, 96, 98, 100) cooperate to the shaft (46) against the Iäntssohub from the fluid pressure in the Keep balance. 8 _a method of manufacturing a multistage centrifugal pump with a divided, elongated housing, an impeller unit formed in one piece with a plurality of impellers, which is arranged within the housing and with a large number of intermediate-stage guide spirals, which are removable within the housing and av / isohen these impellers are arranged, characterized by the following steps a) forging and shaping the material to form the split pump housing, b) Forming and assembling the impeller unit into a fully assembled unit, c) Forms of the Zvlsohenstufen ^ spiral guides and d) Installation of the impeller unit and the intermediate stage spiral guides in the housing to complete the pump _e 20th 9o A process for preparing a multi-stage centrifugal pump according to claim 8, characterized in that the pump chamber in the housing is such auegebildet that the interstage Leitspirälen in the housing attached to v / ground ₀