US1012438A - Centrifugal turbine and similar pump. - Google Patents

Description

E. S. G. REES.

CENTRIFUGAL TURBINE AND SIMILAR PUMP.

APPLICATION FILED SEPT. 13, 1906.

1,012,438, Patented Dec. 19, 1911.

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APPLICATION FILED SEPT.13, 1906.

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APPLICATION FILED SEPT.13, 1906.

Patented Dec. 19, 1911.

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E. S. G. REES.

CENTRIFUGAL TURBINE AND SIMILAR PUMP.

APPLICATION FILED SEPT.13, 1906.

m W 6 m m I a Q y Q a a m 2 m MW 1 w EDMUND S. 'G. REES, OF WOLVERHAMPTON, ENGLAND.

CENTRIFU'GAL TURBINE AND SIMILAR iUMP.

Specification of Letters Patent.

Patented Dec. 19, 1911.

Application filed September 13, 1906. Serial No. 384,456.

To all whom it may concern:

Be it known that I, EDMUND SCOTT Gus- TAVE Runs, a subject of the King of Great Britain, residing at Wolverhampton, in the county of Stafford, England, have invented certain new and useful Improvements in Centrifugal Turbine and Similar Pumps, of which the following is a specification.

This invention relates to centrifugal pumps for incompressible fluids, and. consists in an improved construction wherein the pressure necessary to overcome the head against which the pump is working is in the main produced within the impeller itself by centrifugal force, instead of being produced mainly by the conversion into pressure in the fixed casing of the speed energy of the water generated in the impeller.

The essential feature of novelt of this improved construction resides in t 1e combination of a rotating tank or chamber of large capacity having an inlet or inlets constructed to pick up the water in the usual manner, with a series of peripheral discharge nozzles, preferably rearwardly directed, leading from this tank or chamber, which nozzles are of short length and small width in the direction of the axis of the impeller compared with the Width of the latter, and also of small width in the transverse direction at the point of maximum construction, so that the sum of-the areas of all the nozzles at this point is a small fraction of'the circumferential area of the chamber from which they lead. With an impeller so constructed a large mass of water is maintained under a constant and high pressure Within the rotating tank or chamber, and a part of this pressure is converted into speed energy in the water issuing through the dischar e nozzles. It is found that with nozzles lnclined' from 10 to 20 to the tangent in the rearward direction, .n'iaximum efficiency is obtained when 25 per cent. of this internal pressure 'is converted into velocity in the nozzles, giving a velocity of flow through the nozzles equal to 50 per cent. of the forward e- Un er such circumstances, therefore, 75 per cent. of the pressure corresponding with a given peripheral velocity is provided directly in, the rotating tang, and only the balance has to be derived from the conversion of the speed energy of the water in suitable expan'ding channels in the fixed casing. Consequently, since only a comparatively small part of the total external pressure need be obtained bythe known devices for converting speed energy of the water into pressure, and as such conversion can only be effected with any great efficiency by. means of carefully designed. appliances, the

between the constant pressure maintained by centrifugal force in the rotating tank and the external head increasingly assists in driving the impeller, thereby preventing the power 'taken from the driving mptor from increasing with increasing quantity of water delivered from an impeller running at constant speed. The more the direction of the nozzles approximates to that of the radius of the impeller, the less will be this turbine effect, but theoretically, and within limits also practically, the greater will be the external pressure of the pump,

since the greater will be the absolute velocity of, the water entering the casing. The cross section of the fluid space in the impeller from the eye toward the rim being increasingly large, the relative velocity of the water in the impeller and consequent frictional losses are small, and moreover, since that part of the water path in the impeller in which the relative velocity of the water is at all considerable, viz. the peripheral nozzles, is very short, the frictional losses here are also small.

The fundamental principle of the invention as set forth above is embodied in the various fi ures of the accompanyingdraw peller having a nozzle ring and reservoir I section and a side elevation partly in transally constructed.

verse section of an improved pump as actu- As shown in Figs. 1 and 2 and certain of the other figures, the impeller is constructed with what may be called a hydraulic pressure reservoir or central pressure producing chamber A of large capacity in whicha considerable volume of liquid is stored and maintained. at a high pressure, by centrifugal force due to the rotation of the impeller, inthe region within the peripheral discharge nozzles, and in addition to the capacity of this chamber'being large, its area concentric with the periphery is also large compared with the total area at the point of maximum constriction of the rearwardly di rected discharge outlets D which are formed or between the peripheral vanes B, B. Some of these vanes B are shown as continued inward toward the eye C of the impeller with the object of reducing or preventing slip between the mass of liquid as a whole and the'body of the ini eller, but the same object may be attained y additional vanes which do not-constitute or go to form the discharge nozzles D. As shown in the drawing, the'point of maximum constriction of the nozzles D is a short distance within the eri )hery.' Consequently in this case the velocity of the fluid through the nozzles at the point of maximum constriction is partly re-converted into pressure before the fluid leaves the impeller. In addition to obtaining the reactive effect due to the rear wardly directed streams of liquid, the inde-v pendent velocity imparted to the issuing streams relative to the impeller consequent on the maintenance of the steady pressure within the impeller reservoir e ables a resuit-ant velocity with respect to the casing to be given to the liquid streams which can be varied both in magnitude and direction within wide limits. The ractical advantage of this is that since t e forward tangential component of the velocity of the fluid due to rotation can. be to a large extent neutralized by the rearwardly, directed component due to internal pressure, the resultant velocity of the fluid with respect to the cutwaters E (Fig. 2) and the casing is considerably reduced for any given head and consezuently there is a corresponding freedom who wear in the cutwaters and other parts subjected to the action of the issuing shown in Figs. 1 and 2, the ordinates of'the curves X, Y showing respectively the head in feet, and the brake power absorbed by the pump, the abscissae representing the correspondingvolumes of water delivered per hour measured in gallons. The curve Z-is the corresponding curve of efiiciency derived from curves X, Y. The fourth curve Y represents approximately the power which would be absorbed by a rotary pump of usual construction working under the same conditions in which the power used is substantially proportional to the quantity of water passed through the impeller. The shaded portion between the two power curves is a measure of the turbine efi'ector the power given back to the rim oft-he pump disk, in thecase of a pump constructed according to the present invention, by the extra water passed through the im eller.

In the modi ed construction of Figs. 3 and a, the body of the impeller is cast with a peripheral grid having partitions a, and a separate nozzle ring 6 is shrunk or screwed or otherwise secured on the periphery of the grid. One advantageof this construction is that in order to reverse the direction of rotation of the machine it is only necessary to reversethe nozzle ring, and if cutwaters are used they maybe similarl mounted in a reversible ring on the casing or cover, so

that the machine may be converted: into a pump or a turbine running in either di-- rection.

Figs. 5 and 5 show details illustrating two modifications of the method of attaching the nozzle ring to the body of the impeller, the

ring in the, former case constituting the nozin two parts a, a, one of which s is fixed,

while the other part .9 is slidable therein so as to vary the constriction of the nozzle. The various inner sections 8 may be correlated so as to be moved outward and inward si-' multaneously to the same extent by any suitable means, as for example, by linking them with an internally screwed collar or sleeve .9 movable axially on the shaft by means of a screwed rod, such as 8 In the-complete pump shown in Figs. 8 and 9. the doubly constricted peripheral nozales D formed between the vanes B, B and ing, in which ducts the speed energy due to the absolute velocity of the water is converted into pressure which,- together with the effective static pressure of the water in the impeller, gives the pressure of the water in the delivery pipe 0.

What is claimed is:

1. A centrifugal pump for incompressible fluids, comprising an impeller which is constructed with a liquid reservoir of very large capacity and peripheral outlets leading therefrom and contracting both transversely and circumferentially from the reservoir toward their discharge ends, the constricted parts of the said outlets being very short and the sum of the areas of the constricted parts a small fraction of the peripheral area of the liquid reservoir.

2. A centrifugal pump for incompressible fluids, comprising an impeller which is constructed with a liquid reservoir of very large capacity and rearwardly directed peripheral outlets leading therefrom and contracting both transversely and circumferentially from the reservoir toward their discharge ends, the constricted parts of the said out lets being very short and the sum' of the areas of the constricted parts a small fraction of the peripheral area of the liquid reservoir.

3. A centrifugal pump for incompressible fluids, comprising an impeller constructed with inlet vanes adapted to pick up the'water at the inlet and with a chamber of large capacity for the storage of liquid under pressure within the impeller rim, the passages from the inlet to the pressure chamber being constructed of increasing area from the inlet end so as to deliver the Water at a low velocity of progression to the pressure chamber, and a series of nozzles in the rim of short length and of such a section that the area of the water passage is reduced rapidly in both transverse and circumferential directions from the pressure chamber toward the periphery, whereby the pressure of the Water within the pressure chamber is partly converted into velocity within the impeller.

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

EDMUND S. G. REES.

Witnesses:

EDWARD ARTHUR CRESSWELL, HAROLD VILLIERS PEDLEY.

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