US879059A - Rotary or centrifugal pump operating with auxiliary turbines. - Google Patents

Description

No. 879,059. PATENTED FEB. 11, 1908.

H. LUDEWIG. v ROTARY 'OR GENTRIPUGAL PUMP OPERATING WITH AUXILIARY TURBINES.

APPLICATION FILED APR. 24. 1905.

2 SHEETS-SHEET 1.

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No. 879,059. PATENTBD FEB.11, 1908.

H. LUDEWIG.. ROTARY OR CENTRIFUGAL PUMP OPERATING WITH AUXILIARY TURBINES.

APPLICATION FILED APR. 24. 19055.

2 SHEETS-SHEET 2.

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Java/2502 lzkrz cfizm To all whom it may concern:

. pump wheel into the cells of the 'duit pipes should not excee 20 HEINRICH LUDEWIG, OF CHARLOTTENBURG, GERMANY.

:ROTARY OR CENTBIIUGAL PUMP OPERATING WITH AUXILIARY TURBINES.

Jim-879,069.

Specification of Letters ratent.

Patented Feb. 11, 1908.

Application filedllpril 24. 1905- Serial No- 267.253-

Be it-known that I, HEINRICH Lunnwro, a? subject of the German Emperor, residing at 'No. 7 Spandauerstrasse, Charlottenburg, near Berlin, in the German Empire, professor of "the Koniglichen-Technischen Hochschule ini 'Berlin, have invented certain new and use- $111 Improvements in "Rotary or Centrifugal. Pumps'O erating with Auxiliary Turbines, of which t e following is aspecification.

In centrifugal pumps in which the pump; disk leads directly into the end of the casi -eonnected to the rising main the absolute; velocity of delivery of the pressure fluid is 'mostly lost by concussion and formation of: eddiesywith heights of'lift that are not very *small the velocity is considerable at the com-' mencement, while the velocit one or two. "meters Ipler second, even with considerable lifts. is loss of s eed can, under certain circumstances, be're need by means of-fixed guide blades arranged around the pumpwheel in the known manner. This,however,

necessitates the condition that the j ump ivs'rheel-shall only be driven at a certain avorg able number of revolutions, i. 6. with a cer-' tain peripheral velocity, in order that the ressure against the fixed guide blades'may e-avoided. By means of the guide blades "the-speed of the discharge water from they ide ring is to be converted into pressure 0 the water; -in consequence offthe'gradual alteration of: the sectional area of the cells, as the pressure of-the water in the cells of the guide ring, in; "creases in proportion to :the decrease of speed. This assumption, however, as shown. by ex eriments is only correct to a very,

liniite degree, for, evenwith the most care ful-determination of the sections ofthe cells, "there enerall occurs almost as greataloss as wit a sud on change of section (see O'i'vt'Z' Ingem'eur 1878, page 98,- Schweizerische Banze'itung Vol. 42, No. 8, Fliegener .E'in- 'neuer Weg zm' Berecimwng der Stankur've Zettschmlft fit'r dos gesamte Turb'inenwesen 1906 pages J2 to 14). According to the present invention such losses of energy are entirely avoided by arranging. beyond the guide ring of the pump an auxiliary turbine which acts at motor and converts the kinetic 2 energy of the fluid into energy of rotation,

which is transmitted-back to the pump shaftin the con-.

into the rising so that the-external driving'power for'th'e 'pump for raising the liquid to a certain height is correspondingly reduced In the accompanying drawings are shown *various modes of construction for carrying out the said mventlon.

' Figure 1 shows a longitudinal section of the comblned' ump guidering and turbine ,"Figs.

2-and 3 s ow diagrammatic cross sections 5 thereof; Fig. 4 shows a similar construction k adapted to a compound pump; Figs. 5 and'lfi ngi show a longitudinal section and part cross section of a modification in which the guide passages are'formed with a double curvature $10 that the turbine I acts with an outward ow. Fig. 1' shows a vertical section of an arrangement in which a pum disk P is combined with a turbine dls'k ranged between'thetwo disks .P and Ta there being arfixed ring of guide blades L. In this case P and T are connected together by one and the same boss so as to form a single rotatin body; the pum disk and the turbine dis can, however, e constructed 'as separate bodies. "By-means 0f the uide rin L interposed between the pump isk Ran the turine disk T and abutting directly a ainst these,the'pressure fluid issuing from I with 'the'velocit C (Fi 2) is led as impact fluid to the 'tur ine an issues at the end of the guide'ring (Fig. 3) with the absolute velocity c 'into the turbine wheel, in order, there, to perform work. After the impact fluid of the auxiliary turbine has imparted to this the greater part of its energy it will in leaving the turbine-with the speed 0'; pass directly struction of t e auxiliary'turbine must there+ fore be such that it acts only as turbinemotor and'not also as pump, increasing the pressure.

If the liquid pressures, in front of and'behind the turbine wheel are to remain e ual the auxiliary turbine must act as a so-ca led equal pressure turbine, which has onl "to convert the kinetic ener of thefluid into energy of rotation as abso ute im act head. Also, withinthe guide-channels o the-guide 'ring any alteration in the pressure of the liquid passing through has to be avoided.

The interposed guide ring'is therefore to be constructed (in contradistinction to the construction of the; ordinary guide rings applied .beyond thepump disk) with enlargement'of mainof'the pump. The conthe section of the guide passages in such manner that c =c Leaving out of consideration any unavoidable guide or friction resistance, the pressure at the outlet of the pump disk at the radius 1",, will be the same as in front of the turbine .wheel at the radius 1" e and beyond the turbine wheel at the radius 1%. Consequently the pump has to be calculated in the same way as with theold construction of )ump without rear guide ring as though the kinetic energy of the fluid were almost entirely lost by impact against the pump casing. This a parent loss is returned by means of the auxiliary turbine the more so the higher is the ell iciency of the auxiliary turbine. To effect this the inlet radius 7",, of the auxiliary turbine is chosensmaller than the outlet radius 1",, of the pump wheel. The advantage of this is shown from the following. The-impact speed 0, corresponds, with a smooth motion of the turbine, to a certain peripheral velocity W of the turbine wheel.

Consequently 1/ is dependent upon the peripheral velocity '12,, already determined, of the pump. The wheels P and T being arranged on one and the same shaft have the same speed, so that o /v,,=r /r According to the known rules of turbine construction it is of advantage, for obtaining a good useful effect, if the peripheral s eed o is I smaller than c viz. only about ha I? as great,

but as c is made equal to 0,, consequentl 4/ is smaller than 0,. With the pump wheel: according to the choice of the angle of the blades and the speed of the pump, the absolute speed of issue c of the pressure water is dependent upon the-chosen peripheral speed v of the pump wheel.

In order to keep the friction losses for water small in the guide ring with a great c it is of advantage to make 0,, smaller than 0,, which may be attained by a suitable choice of the angle of the 'pump blades.

With o smaller than 0,, and 0,, smaller than 1),, it follows that'o is smaller than.

1),. But the conditionthat 'v is to be smaller than a, is attained by making 1",, smaller than 1",. This condition which .determines the dimensions'of the inlet and outlet radii of the intermediate guide ring is therefore an essential feature of the invention. Consequently in the construction shown at Figs. 1, 4, 5 and 6 the inlet radius r',, is made smaller than the outlet radius 1",, of the pump disk. As shown'in Fig. 1 the guide ring and the turbine ring of the auxiliary turbine can be so arranged that the issuing water is led off in axial direction directly into the rising main. This arrangement is also facilitated by the fact that r,, must be chosen smaller than T, and consequently the outlet radius ,r, of the turbine wheel can also be made so small that'the outlet is situated directly around the shaft. With such axial discharge of the liquid from the turbine the ini roved ump construction is rendered suitab e for t e combined construction of severalpumps in the form of a compound pump, as shown in vertical section in Fig. 4, as in this case the liquid issuin axiall from the auxiliary turbine can be led direct y to the inlet of the next pump disk.

If the auxiliary turbine is constructed for equal pressures of'the inlet and outlet liquid,

it can be constructed according to the usual forms of equalpressure turbines, either as axial or as radlal turbine- If an outward- .flow radial turbine be chosen then, as shown in Figs. 5 and 6, the water issuing from the turbine is led through an annular collecting channel to the. rising main of the pump,

which is in that case arranged at the side of.

such channel. For enabhn such an arrangement to be used, the uide ring L must be formed with a' doub e curvature, as

shown.

The'intended advantage ofthe new construction over pumps of known construction with guide ring can only'be attained if the auxiliary turbine acts with good useful effect. It is, however, known that the equal pressure turbines are inferior as regards the useful effects obtained in comparison with turbines operating with fall of ressure (reaction or excess pressure turbines) as is shown by the present general adaptationof the Francis turbine as excess pressure tur bine, that is, with fall of pressure, which, as is known, is effected by a proper choice of the .angles of the blades, and in particular of the cross sections of the passages of the turbine wheel. In this particular case the water pressure at the line of the turbine radius 1", is arranged to be greaterthan that at the discharge radius 1",. In consequence of the condition c 0' the water pressure at the line of radius r, is as great as at the line of radius r Consequently in this case the pump must be calcu ated as though it were mtended for a eater lift, and therefore the velocity 0,, an the kinetic ener y of the fluid must also be greater, but t e greater amount of rotary work re uisite for this purpose isre ained in the tur ine with particuarly o0 useful effect, so that the total useful e ect of the pump having the reaction turbine is increased as compared witha pump with equal pressure turbine. To this improvement in the useful effect has to be added the fact that the excess pressure turbine can be-constructed in the same way as the usual form of Francis turbine of American coninto practical effect, I claim:

1. In an apparatus of the class set forth, a

centrifugal pump, with an auxiliary turbine of the turbine, the radius of t e outlet of the pump and inlet of said guide ring being greater than the radius of the outlet of-the guide rin and inlet of the turbine, substantially as escribed.

2. In an apparatus of the class set forth, a

I centrifugal pump, with an auxiliary turbine o eratin as motor mounted on the same s aft an revolving at the same speedas the I pump, and a fixed guide ring interposed between the outlet 0 the pum and the inlet of the turbine, the radius of t e outlet of the pump and inlet of said guide ring being greater than the radius of the outlet of the guide ring and inlet of the turbine, and the j outlet of the turbine being arranged to immediately surround the pump shaft so that the liquid issues therefrom in the axial direction substantially as and for the purpose described. A v 1 p -3. In an apparatus of'the class set forth, a centrifugal pump, an auxiliary turbine operating as motor with drop of pressure (reaction turbine) mounted ontthe same shaft and revolving at the same speed as the pump, and a fixed guide ring interposed between the outlet of the pump and the inlet of the turbine, the radius of the outlet of the. pump and inlet of said guide ring being greater than the radius of the outlet of the guide rin and inlet of the turbine, substantially as escribed.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

HEINRICH LUDEWIG.

Witnesses WoLnEMAR HAUPT, HENRY HASPER.

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