US2255287A - Double vane impeller - Google Patents

Description

Sept. 9, 1941. o. JACOBSEN DOUBLE VANE IMPELLER Filed Aug. 12, 1940 2 Sheets-Sheet 2 Patented Sept. 9, 1941 NETE STTES 2,255,287 DOUBLE VANE WELLER Oystein Jacobsen,

signer Montgomery County, to The Duriron Company,

Ohio, as-

Inc., ayton,

Ohio, a corporation of New York Application August 12, 1940, Serial No. 352,237

4. Claims. (01.103-103) This invention relates to centrifugal pumps of the open runner type, and in particular to such pumps for pumping corrosive fluids, or other liquids containing solid matter in' suspension.

The primary object of this invention is to provide an open runner centrifugal pump with means for preventing flow of the pumped fluid along the drive 'shaft and through the packing thereof. 7

Another object is to provide a centrifugal pump of the character mentioned, having an impeller mounted on a shaft supported within a casing, this impeller having a dual pumping function, one consisting of pumping the main body of fluid or. fluid-like -material from the pump intake chamber, and the other consisting of pumping the leakage fluid or fluid-like chamber adjacent the packing so as to prevent the leakage of the fluid or the fluid-like material along the shaft.

Another object is to provide a centrifugal pump having an impeller with dual sets of vanes, one set of vanes being of the open runner type and working on the centrifugal principle to pump one portion of fluid or liquid containing solid matter in suspension, the other set of vanes working upon the fluid-like material from another portion of-the casing.

.Another object is to provide a centrifugal pump of the open runner type having separate chambers within the impeller, one set of vane chambers opening into the pump intake chamber, the

other set of vane chambers opening into a chamber adjacent the pump shaft packing.

Another object is to provide a centrifugal pump' having a casing with an intake chamber and an impeller mounted on a shaft, with vanes secured at one side to the impeller and open at the other side to separate the interior of the impeller into two sets of vane chambers. The vane chambers of one set are directly connected to the'pump intake chamber, the other set of vanes being closed at the side adjacent the open face of the impeller and connected to a chamber communicating with the pump shaft packing, and connected to the first set of vane chambers by means of restricted ports setting up a pumping effect within 'the second set of vane chambers.

From another aspect of the invention this action is enhanced by providing at least two apertures or ports in the vane chambers, which are connected'to the chamber communicating material from the with 'the pump shaft packing, one of these aper- 55 portion 8 and a l the pump casing.

tures opening into the adjacent vane passageway at the position of a zone of contraction which is normally formed at the inner-ends of the vanes.

The invention will be better understood when the following specification is perused in connection with the accompanying drawings.

In the drawings:

Figure 1 is a central longitudinal section through a preferred embodiment of the pump of this invention.

Figure 2 is a perspective view looking at the edge of the impeller, with a portion broken away to show the improved vane chambers by which a jet action is produced on the leakage fluid.

Figure 3 is a sectional View of the pump taken along the line 3-.3 of Figure 1.

Referring to the drawings in detail, the numeral l designates a heavy slightly conically shaped disc or plate forming the so-called back plate of the impeller. This plate is preferably made of an acid-resisting metal, such as silicon iron,'in case it is desired to pump corrosive fluids either in liquid or partially liquid form.' This back plate is provided withan outer flange portion 2, and there is a number of openings 3 cored through the plate to eliminate end thrust and V The inner portion of to effect proper balance. the plate terminates in a hollow outwardly 'eX- tending hub member 4, and intermediate this hub member and the flange portion 2 there is a conically shaped extension 5, cored out as in-- dicatedat 6 in order to allow entrance of liquid into impeller vanes 61.

The drive shaft 1 is provided with a shouldered threaded portion 9, these portions being surrounded by a cast insert l6, pref erably of bronze, firmly to secure the shaft to the impeller. Directly opposite the hub 4 and projecting inwardly there is a' curved extension H, forming with the hub 4 a compartment which readily receives the cast material the shaft is held in place. There are discs 12 of packing material surrounding the shaft 1 and contained within ahollow hub extension 13 of The latter is provided'with an inwardly projecting annular flange M. A sleeve Hi surrounds the shaft 1, as seen in Figure 1.

The pump casing is constituted of a heavy V casting having a side plate H5 at the left and a similar plate It at the right, the plate l5 being provided with outwardly extending surfaces ll, [8 as wearing surfaces for portion 2 and the hub portion 5, respectively,

the pump. The side plate I! has a peripherally It! by which during operation of l 6 is prohaving a surface 24 which bears against an adjacent surface 25 through a gasket 26.

The plates l5 and of castings secured together in any suitable carries bolts 28, extending through the ring and being secured to the pump support 29 by means of the nuts 30, 3| at each end of the bolt. It will be understood that the castings I5, l6 are constituted preferably of a corrosive-resisting metal, such as silicon iron, so that it is practically impossible to machine this metal, and the parts [5, l6 must port 38,

The vanes 4| clearly in Figure :3,

These vanes are preferably cast integral with the back stitute a so-called open runner form of impeller in that the vane compartments are, for the most part, entirely open at that side which faces the casting l6. These vanes preferably have a depth, i. e. that they extend to the right from the back plate such a distance that the right-hand edges p mp.

The passageways formed between the vanes may be broadly termed Venturi shaped in that there is a throat portion 42 A study of the drawings will show that as the impeller is rotated there is a tendency for the speed of the impeller, to leak through the space between the surfaces 2, l1, also between the surfaces that two pairs of oppositely positioned vanes 41 are connected together at their inner ends by a closure member 48. Each of these closure members is provided with a pair of apertures 49 and 50, respectively. The aperture 50 is pref- ThlS enhancement of the suction pairs of vanes 47 in order to take care of all of the leakage fluid within the pocket 46, leaving the remaining vanes entirely open at their inner ends to serve the normal pumping functions of the impeller.

It will be noted in Figure 3 that the vanes '6'! do not have quite the same curvature as the-open vanes M. It has been found in practice that the vanes 4'! should preferably have less sweep than the remaining vanes so that the vanes 4i take on a shape which S-shape. In order to prevent any swirling or eddy current action between the outer tips of the vanes 41 and the next vane M in sequence (de pending on the direction of rotation) it has been found desirable to introduce a pair of blades or vanes 53 which serve merely to maintain the volute or arcuate direction of the fluid as it leaves the impeller.

In case the pump is employed for pumping fluids containing solid materials which might have an abrasive effect, it is apparent that the space between the right-hand surfaces of the vanes M and the left-hand surface of the casting l6 willbecome greater and greater during operation of the pump. It will be understood that it would be impractical to take up this wear by moving the impeller as a body to the right, because in that case greater spaces will be left at the surfaces 2, l1, also between the surfaces l8 and and at the flange Hi to permit considerable flow of leakage fluid into the packing box. While small spaces between the right-hand surface of each vane M and its adjacent casing surface have little or no effect on the output of the pump, it has been found that these small spaces greatly affect the efliciency with which the compartments contained between the vanes 47 perform their suction effect on the leakage fluid, and the facility with which this fluid is moved through the compartments into the volute casing 19.

In accordance with the present invention there is provided a plate or cover 54 over each compartment formed between the vanes 31, this cover serving the purpose of isolating the liquid flowing through the vane compartments 41 from any fluid which tends to pass hand surfaces of the vanes and the casting It. This cover is preferably cast integral with the vanes 41 so that the compartment between the vanes is closed on the four sides, and also at the inner end except completely open at its outer or peripheral boundary. The compartment between the vanes 41 including the openings formed by a coring-out operation so that there are no practical difficulties in the two compartments through which the leakto flow. It will be noted that, regardless of the amount of wear which takes place at the right-hand surfaces of the vanes 4!, 41 (as seen in Figure l) due perhaps to abrasives in the fluid, none of closed compartments or in any other manner deleteriously affect the passage of leakage fluid from the pocket 58, through the opening 52 and thence into the closed compartments. The closed compartments are therefore free of all fluid or fluid-like material except such fluid as is drawn through the openings 49, 5! thus causing the closed compartments to exercise a great suction effect on the leakage pocket 48.

It will be understood that I desire to comprehend within my invention such modifications as come within the scope of the claims and the invention.

might broadly be termedbetween the rightfor the opening 59, 5B, but is the fabrication of 4 this fluid is able to enter thev fluid which collects in the 49, 59 can be readily Having thus fully described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A fluid pump of the centrifugal type comprising a casing'and an impeller adapted to rotate inthe casing, said impeller including a back plate, vanes secured thereto to leave open passageways between the vanes and the side of the casing cover opposite to said back plate, means for draining the leakage fluid which collectsbetween the back plate of the impeller and the adjacent surface of the casing, said means including a closure member across the inner ends of at least one pair of vanes but less than the total number of vanes to form a compartment closed at the inner end and open at the outer end, an opening in said closure member communicating with the space between the back plate of the'impeller and the casing through a passageway located within the compartment andclosely adjacent the opening in the closure member whereby leakage fluid is caused to flow through said passageway into the compartment and out ofthe impeller through the open endof the compartment, and a plate spanning each pair only of saidvanes which areintcrconnected by a closure member and at the side opposite said back plate.

2. A fluid pump of the centrifugal type comprising a casing containing an impeller formed of a plurality of vanes secured to a back plate to leave open passageways between the vanes and the side of the casing opposite said back plate, an inlet passageway leading to the center of the impeller and communicating with the passageways between the vanes, an outlet passageway leading from the periphery of the impeller, said impeller being rotatably mounted adjacent to a wearing plate, and means for draining the fluid which passes between the impeller and the wearing plate, said means including a closure member across the inner ends of at least one pair of vanes but less than the total number of vanes to form a compartment which opens into the outlet passageway, said inlet passageway having a larger area than the vane passageways whereby a zone of contraction is normally produced at the junction between the inlet and vane passageways, said closure member having an aperture which opens into the adjacent vane passageway at the position of said zone of contraction and communicates with the space between the impeller and the wearing plate through an opening 10- cated within the compartment and closely adjacent the aperture in the closure member, said compartment being completely closed except for said aperture and opening at one end and the opening at the other end which leads into the outlet passageway.

3. A fluid pump of the centrifugal type comprising a casing containing an impeller formed of a plurality of vanes secured to a back plate to leave open passageways between the vanes and the side of the casing opposite said back plate,

an inlet passageway leading to the center of the impeller communicating with the passageways between the vanes, an outlet passageway leading from the periphery of the impeller, means including a shaft and a stuiflng box for rotatably mounting said impeller, fluid from leaking along the shaft into the stuffing box, said means including an apertured closure member across the inner ends of at least one pair of vanes but of vanes to form a compartment which opens into the outlet passageway, said means also inmeans for preventing' less than the totalnumber cluding an opening in the impeller in the region and communicating with the passageways beof the stuffing box, said opening being located tween the vanes, an outlet passageway leading area than the vane passageways whereby a zone 10 top plates which are spaced from said back plate of contraction is normally produced at the juncto form closed compartments which are open tion between the inlet and vane passageways, only at the outer ends and closed at the inner means for increasing the suction effect on the ends, the remaining vanes being provided with leakage fluid in said compartment, said means inonly said back plate whereby the compartments eluding a second aperture in said closure member 15 formed thereby are open at one side, also open positioned in the region of said zone of contracat the inner and outer ends, said closure member the outlet passageway. caused to pass through the closed compartment A fluid pump of the centrifugal type cominto the outlet passageway, said opening being ity of vanes secured to said back plate, an inlet ber. passageway leading to the center of the impeller OYS'IEIN JACOBSEN.

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