US903658A - Centrifugal pump. - Google Patents

Description

Patented Nov. 10, 1 908. 2 SHEETS-SHEET 1.

' 4 ire/51mm.

L. BELLOT. 'GENTRIFUGAL PUMP. APPLICATION FILED snr'r. 1, 1904.

903,658. Patented N0r.10,1908. I 2 SHEETS-SHEET 2. Flg .9.

LOUIS BELLOT, 0F PARIS, FRANCE.

OENTRIFUGAL 5am.

{Specificationot Letters Patent.

Patented. Nov. 10, 1908.

Application filed September 1, 1904. Serial No. 222,992.

To all whom it may concern: I

Be it known that I, LoUIs BELLOT, of 3 Boulevard Richard Lenoir, in the city of Paris, Republic of France, ClVll engineer, have invented Improvements in and Relating to Centrifugal Pumps, of which the following is a full, clear, and exact descrlption.

Experience hasdemonstrated that: (1) the efliciency of centrifugal pumps is so much the greater according as the-suction height is less; 2) that themaximum height at which the water is maintained in the suction column during working does not exceed 8 meters; (3) that above this height of 8 meters pumps lose their priming notwithstanding the presence of a footvalve.

. From the above it may be concluded that,

if during the operation of the pumps, water rises in. the suction pipes to a maximum height of 8"meters it is because the vacuum produced in this pipe balances a column of water 8 meters high. It is therefore apparent that a pump which is submerged and thus utilizes hydrostatic pressure, has greater efficiency than one not submerged an'd into which liquid must be drawn by air pressure alone; and this result is promoted by directing the liquid currents .into

guldes constructed and arranged as hereinafter described.

If, now we assume that the pump is immersed iri the water that it is desired to suck and' that this pump is acting, the practical velocity with which the water guide vanes will be equal to i meters +fi),

8 meters being the maximum reduction of pressure found previously and h the verticaldistance from the level of the waterthat is to be sucked to the center of the distribution apertures. If now It is made equal to 1 meter, 2' meters, 3 meters, 4 meters, 5 meters, the practical generating charge of the velocity of discharge of the water in the its passage through the orifice -of the dis--- tributer, the cone usion will be arrived at that the practlcal charge 1s, 1n thls'case, ex-

grammatic view of a zon'tal section. the pump by will leave the actly equal to the theoreticaleharge, 11, 33,- 12', 33,- 13, 33,- 14, 33,-- 15, 33 v meters.

Having given this preliminary explanation, in, order that this pump may be readily and clearly understood, I will now describe the same with reference to the accompanying drawing, in which it is given byway of example,.and in which:

Figure 1 represents line X Y of Fig. 1. Fig. 3 is in part a dia- 7 portion of the pump, lllus'tratmg also the theory of the operation. Fig. 4 shows the form of pump in question in vertical section on the'line X Y of Fig. 5. Fig. is a horizontal section through the same pump. Fig. 6 represents a system of transformer in vertical section on the line X X of Fig. 7 and forming part of this kind of pump. Fig. 7 is a horizontal section. Fig. 8 represents cross sections taken on the line 1l, 2 2, 3-3,- 4-at,+ 5-5,- 6'6,- 7-7, and 88 of this transformer. Fig. 9 shows a modification of this transformer, in vertical section .on the.- line Y of Fig. l 0, and Fig. 10 is another hori As shown in Fig. 1, in this form of contrifugal pump, a sieve or enlarged perforated pipe A. is surmounted by a casing B containing a slidecock which may be operated by a horizontal gear through the me dium of a vertical shaft C, having a handwheel'at the top. The pump body, properly so called, is arranged within a cylindrical casing or receptacle D, made preferably of cast iron and arranged-at a lower level than the water which is to be raised. The water entersthe fixed vertical distributor E and is sent outward Into the movable annular hol- 'low rim having guides or buckets as hereinafter explained. and adapted to rotate with a vertical hanging shaft G supported upon a ball bearing H and provided with a pulley which may be driven from a motor of any suitable kind. The pump also comprises an annular gate or shutter, constructed prefer ably of bronze, supported upon antifriction balls and provided with a beveled crown. The *opening or closing movement of the gate is given by means of a horizontal shaftthe pump in vertical" section. Fig. 2 IS a horizontal section on the.

and a vertical shaft J geared therewith and having a hand-wheel. for rotating it. Exterior to the said gate I, is arranged a hollow annulus Kfrom which water is discharged into a conduit L, M, the latter indicating the vertical, portion, and which is in practice rovided with a stopcock. As shown .in

i 's. 2 and 3 of the drawing, the guides or pallets F have a double curvature, the face geingfconcave from a to b and convex from From point 6 to point f, which constitutes the outer portion of the guides, the im ing- 'ing current of water exerts very little orce.

This convex part 5 f, which joins the concave part a b tangentially, acts practically as a piston, forcing before it the impinging current of water as it is about leaving the turbine.

In the diagrammatic representation, Fig. 3, the dotted line W of the parallelogram may indicate the speed with which the water traverses the outlet of the turbine, and V the speed of rotation, while the diagonal V representsthe resultant of the two speeds or velocities, W,.V'.

In theform of pumprepresented in Figs. 4 and 5, the passages A 4 have sides which are curved practically upon the same line as the guides F before described, butthe passages are slightly contracted from the inner ends outward and the portions intervening the passages are solid as shown by hatching.

In consequence of this contraction of the passages A, the discharge of liquid is "dimimshed correspondingly in volume. In

Fig. 5 the outlet has a portion only-ofthe circumference of the wheel, it being the are indicated at a b, c. The adjacent and exterior passage has a diverging wall so that the area for passage of water constantly increases from c to f as indicated-by the cross hatching. The nozzle D' into and through which the liquid discharges, is tapered or enlarged correspondingly, and by thls form of the outlet passage or evacuation path, provision is made for How of the liquid so that there is no shock or loss of power and effect between the streams discharged from thewheel proper intothe passage. It isobvious, however, that owing to the increasing area of the dischargepassage from 1ts inception to the outer end of. the tapered nozzle D, the velocity must gradually decrease corresponding to the progress- We enlargement.

' As specified in Fig. 5, the construction of the casing is such that discharge of water takes place from a portion only of the pump. TlllS form of ,pump may be employed whenever the column of water to be lifted is very light. The outlets are relatively large, so

that their obstruction by foreign bodies, such.

as small pebbles, in the water, is avoided.

Instea of making the nozzle of conical i form as in Fig. 5, it might be made of curvilinear form concentric with the pump and of greater or less development.

In order to obtain a maximum efliciency .around it in the annular zone A313 with the said centrifugal pum s it is notv sufiioient to effect the admission without shock and. the discharge with the greatest possible velocity in order to balance the greatest height :of ascensional column, it is particularly necessary that at the discharge,

'the liquid streams should not encounter with shock the other liquid streams in movement in the evacuation passage. This result is ob,-

tained with the form of transformer which is hereinafter described.-

As shown in the drawing (Figs. 6 and-7) this transformer is constituted by an annular crown surrounding .and' concentric with the pump proper and provided with diverging walls of rectilinear or cur-\ 'ilinear form 1 in such a manner that all the liquid strea'ms issuing fromthe pump traverse this crown ofconstant sectionwith an equal velocity. This Velocity in passing through the amin lar zone represented by the circle A 13 C (Fig. 7 is a function-of the cross section and may be, according to clrcumstances 2, 3,

4, 5 10 times less than that with which the liquid streams have left the pallets 'of the pump. In other words, the annular zone referred to is the neck or throat through which the water enters the scroll or volute 'passage represented .in Fig? 6, and at the right hand side of the drawings constituting Fig.- 8, and the speed at the passage may be two, three, four,. five, or even ten times weaker than that with which the water left the pallets of the pump, such result being due to the two divergent. walls of the first path of evacuation which gives a passage two to ten times larger than the issuing section of the turbine.

In order that there may be no shock against the liquid streams issuing from the zone A B G and those in movement in the evacuation path, it is necessary that the velocity of these latter actly the same as that of the former. This result is obtained by giving to the first part .of the evacuation path D E F? an 1ncreas-' a continuous reduction of velocity so that.

at the'point-H the velocity has become the minimum and equal to that which the water should have in the ascending column. The

arrangement represented in Figs. 6, 7 and 8 is particularly applicable to pumps which are intended-to force liquid to a great height.

The modification represented in' Figs. 9

streams, should be .ex-

and dimensions of this form of pump may is based upon theand 005s the drawing same principle as the above but-it is more particularly applicableto pumps for, foreing liquid to esser heights.- In this case,

discharge velocity of the puinp being con siderably less, the second evacuation path is replaced by a conical nozzle the section of which increases gradually in such a manner that .the velocity of flow into H is equal to that-of the liquid in the ascensional column.

ItLwillpof coursebe understood that this transformer may be applied equally well to the said pumps mounted upon vertical or horizontal shafts. I

The forms, details, accessories, materials of course varywithout thereby in any way changing the principle of this invention. Thus, for example, the pump may be arranged upon a horizontal shaft. in placing it at a higher level. It is also possible to employ tWo or more circular forcin crowns,

in mounting them one upon the ot er or in rendering them as a]. the vertical or horizontal shaft,

cave portions of the guides being arranged contiguous to the said central distributer, so as to utilize the first impact of the liquid (while the outer convex part of the guldes and operated as described.

The foregoing specification of my I improvements in and relating to centrifugal serves as a piston,-'the Whole being arranged pumps, signed by me this 19th day of Aua gust, 1904. p r I LOUIS BELLOT.

' Witnesses:

H NsoN' C. Coxa, MAURICE H. PINUET. f

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