US2461925A - Self-priming centrifugal pump - Google Patents

Description

H. E. RUPP SELE-PRIMING CENTRIFUGAL PUMP Feb. 15, 1949.

Filed Sept. 5, 1946 4M 7 2 $0 J 3 a q." 7 H W a 5 m 5 ATTORNEY- Patented Feb. 15, 1949 SELF-PRIMING CENTRIFUGAL PUMP Herbert E. Rnpp, Mansfield, Ohio, assignor to The Gorman-Rupp Company, Mansfield, Ohio, a corporation of Ohio Application September 5, 1946, Serial No. 694,930

11 Claims.

vision of a pump casing having an impeller and impeller housing or chamber and providing inner and outer volute discharge passageways, such passageways cooperating with the particular type of impeller vanes in a manner to produce improved pumping operation under normal conditions of liquid pumping and to control automatically the direction of the liquid flow within the pumping chamber, responsive to an unbalanced condition in fluid density which necessarily is accompanied by a fluid pressure differential. This action brings about a reversal in the direction of fluid flow in the outer volute discharge passageway causing a recirculation of the fluid outwardly through the inner volute passageway and then inwardly through the outer volute passageway and a repetition of the cycle until balanced fluid density and pressure are re-established.

The invention also includes the use of an impeller having vanes of arcuate shape, being backwardly curved and preferably partially overlapping one another, and having a low tangential angle in relation to the impeller orbit. The outer surface of each of the vanes is curved progressively from an intermediate position of the impeller radius toward the orbit of the impeller and thus has a reaction against the fluid in the adjacent passageways similar to that of a cam surface, whereby through rapid rotation of the impeller highly eflicient pumping and pump priming action are brought about.

The invention also includes a method of operation in fluid pumping wherein is established two partially concentric volute fluid discharge passageways about a center of rotary fluid discharge and so proportionin the outer passageway in relation to the inner passageway that reverse fluid flow will be established in the outer passageway when a difference in fluid density and pressure occurs in and adjacent to the respective passageways, until the fluid density and pressure adjacent the center of rotation again reaches a balanced relation, and thus restoring the original fluid flow automatically upon the restoration of such balanced fluid density and pressure.

The invention is applicable to a centrifugal pump arranged in the conventional vertical position and is also adapted for use in a centrifugal pump arranged in horizontal position. The horizontal position. The horizontal type of pump is very eflicient and is of particular value in cases where a pump casing of reduced height is required for certain installations.

The principal object of the present invention" is to provide an improved self -priming centrifugal pump.

Another object of the invention is to provide a centrifugal pump of high efliciency wherein a pair of partially concentric volute fluid passageways are provided through which fluid is discharged in the same direction by the pump impeller under normal operation, but in which reverse fluid flow will take place in the outer passageway automatically upon the unbalancing of fluid density and pressure within the pump impeller chamber and inner passageway.

Another object of the invention is to provide in a centrifugal pump an impeller the blades or vanes of which have a low tangential angle on the outer surface in relation to the impeller orbit.

Another object of the invention is to provide a method of pumping liquid wherein a pair of partially concentric volute fluid passageways are provided, with a fluid flow automatically reversing direction in the outermost of said passageways in response to unbalanced fluid density and pressure within the pumping chamben.

Other and further objects of the invention will appear in the course of the following description.

The annexed drawings and the following description set forth in detail certain means and one mode of carrying out the invention, such disclosed means and mode illustrating, however, but one of various ways in which the principle of the invention may be used.

In said annexed drawings:

Figure 1 is a side elevation, partly in section, as seen along the line I-I in Figure 2, looking in the direction of the arrows, showinga selfpriming centrifugal pump, embodying the principles of the invention;

Figure 2 is a central vertical sectional view of the pump shown in Figure 1, as seen along the line 2-2, looking in the direction of the arrows;

Figure 3 is a fragmentary view of the pump chamber shown in Figure 2, illustrating the re verse direction of fluid flow in the outer area of the pumping chamber upon the unbalancing of the fluid density;

Figure 4 is a horizontal sectional view of the apparatus shown in Figure 5 as seen along the line 4-4, looking in the direction of the arrows;

Figure 5 is a central vertical sectional view of the horizontal type pump, embodying the principles of the invention, as seen along the line 5-5 of Figure 4 looking in the direction of the arrows;

Figure 6 is a fragmentary view of the pump chamber shown in Figure 5, illustrating the reverse direction of fluid flow in the outer area of the pumping chamber upon the unbalanclng of the fluid density;

Figure 7 is a fragmentary vertical sectional View showing the intake passageway of the horizontal type pump, as seen along the line 1-! shown in Figure 1, looking in the direction of the arrows;

Figure 8 is a view partly in section on the line 8 of Fig. l;

Figure 9 is a vertical sectional view of the apparatus shown in Figure 5, as seen along the line 99, looking in the direction of the arrows, and showing the intake passageway of the pump in relation to the fluid dividing member; and

Figure 10 is a vertical sectional view of the apparatus shown in Figure 5 as seen along the line ill-40, looking in the direction of the arrows.

As is clearly shown in Figures 1, 2, 3, 7 and 8, the vertical type of pump is provided with a pump casing I, having an intake line 2, connected with the intake passageway 3, within the casing and leading downwardly to the impeller chamber 4, within which is housed an impeller 5, preferably in the form of a disk provided with three vanes 6. The impeller is open on the intake side and is rotatably supported on a shaft 1, journaled in the casing and in a standard 8, mounted on the base plate 9. It carries a drive pulley ill at its free end. A suitable packing gland II is provided where the shaft enters the casing.

The impeller chamber 4 has side walls closely spaced from the sides of the impeller, but has marginal clearance of volute form forming a flow space do about the impeller orbit.- The vanes of the impeller have close clearance at the cut-off member I2 at the base of the separating and discharge chamber i3, and the vanes are each formed of arcuate shape with their outer surfaces l4 extending progressively outward in a backward direction, or opposite to the direction of rotation, and, as stated, have close clearance from the cut-off member l2, atthe base of the separating and discharge chamber I3.

In order to provide for normal distribution of liquid under the influence of the rotating impeller to the separating and discharge chamber [3 and also to provide for liquid recirculation and pump priming action when air or gas is received in the pump, or a mixture of air or gas with liquid is received through the intake passageway, provision is made in the flow space 411 for a dividing member 16 disposed substantially concentric to the impeller orbit, but intermediate the orbit and the adjacent end wall of the pump chamber and extending from a point l8 anterior of the cut-off l2 in the direction of liquid flow a predetermined distance and terminating at a point spaced above the cut-off member I2. This dividing member thus separates only the main portion of the liquid in the flow space in and the separated portions thereof are united at the lower portion of the separating and discharge chamber.

The position of this dividing member or wall I I 6 will vary in pumps of different size and capacity. The dividing member is curved in such a manner as to provide two partially concentric volute passageways in the flow space 4a and leading to the separating and discharge chamber.

The impeller is formed to cooperate with the adjacent volute passageways to a maximum degree through its special type of construction. It is preferably provided with three vanes, as stated. in overlapping relation to each other and it is imperative that each of these vanes is positioned at a low tangential angle with reference to the impeller orbit, for the best performance, so as to have what is in effect cam action against the fluid overlying the outer surface of each vane.

The cooperation of the impeller blades with the adjacent fluid passageways is of particular importance when air or gas enters the impeller chamber and has to be eliminated before the pump operates at fullefliciency on liquid. When the pump is full of liquid, the two overlapping volute passageways act as a single undivided discharge passageway for the movement of liquid under the influence of the impeller to the separating and discharge chamber 13 and thence to the discharge outlet 2|. Under such conditions,

the liquid is balanced and there is uniform fluid density in the pump chamber and the respective passageways.

In such case the fluid enters the separating chamber through the. outer volute passageway H, by passing beneath the inner edge i8 of the dividing member l6, and also fluid is discharged on the opposite side of the member I6 through the companion volute passageway, the separated passageways merging at the base of the separating and discharge chamber i3, and being discharged through the discharge line 2|, when the impeller is operating on a liquid of substantialiy balanced fluid density and pressure.

The intake line 2 is preferably provided with a check valve 22 to maintain a fluid supply within the casing when the pumping action is interrupted.

By providing the dividing member [6 the pump maintains full efficiency in normal operation just as though no dividing member was provided.

However, when the fluid density is reduced in the impeller chamber and inner passageway by the entrance of air along with liquid or air alone through the intake passageway, the dividing member provides-an automatic control for maintaining the effective action of the pump and rapidly eliminating the excess air from tne liquid supply. This action, as stated, is of an automatic character and is responsive to an unbalance of the fluid density within the impeller chamber and inner passageway, and the outer passageway.

When such decrease in fluid density in tne impeller chamber and inner passageway through the introduction of air or gas with the liquid supp.y takes place, the liquid within the outer volute passageway ll will reverse its direction of flow due to a combined effect of the shape of the blades, especially as to their outer surfaces and their general low tangential angle relative to the impeller orbit, and also to the positioning of the dividing member at a critical point in the flow space 4a and the proportioning of the subdivided fluid flow so as to be responsive to unbalanced fluid density in the flow space and the respective passageways.

The reversal of fluid flow is shown in Figure 3. It will be noted that the flow is downward toward the impeller in the passageway 11, and not upward as shown in Fig. 2, so that air-free liquid will follow a recirculation path back to the lower area of the flow space M.

The action is substantially similar in the horizontal type of pump, or low-ceiling installation as shown in Figures 4, '5, 6, '7, 9 and 10. Many of the parts of the horizontal type pumps are practically identical with the vertical type, but obviously the positions of the intake line 3| with its valve and the discharge chamber 34 are changed. The base of the chamber 34 is changed in shape and it is formed with suitable supporting flanges or foot members 35, 36. The other parts have been given numbers corresponding with the vertical type of structure as the casings are substantially identical except as stated.

Other modes of applying the principle of my invention may be employed instead of those explained, change being made as regards the means and steps herein disclosed, provided the means stated by any of the following claims or the equivalent of such stated means be employed.

I, therefore, particularly point out and distinctly claim as my invention:

1. A self-priming centrifugal pump having an impeller chamber, an intake connected to said impeller chamber, a rotatable impeller mounted in said impeller chamber, a discharge chamber, a cut-off at one side of said impeller chamber and related to the orbit of said impeller, and an arcuate wall in said impeller chamber on the output side of said impeller and in the plane thereof, said wall being spaced from the orbit of said impeller and the adjacent end wall of said impeller chamber and forming on its opposite sides flow passages connected to said discharge chamber.

2. A self-priming centrifugal pump having an impeller chamber, an intake connected to said impeller chamber, a rotatable impeller mounted in said impeller chamber, a discharge chamber, a cut-off related to the orbit of said impeller at one side of said impeller chamber, and an arcuate wall mounted in said impeller chamber opposite the output side of said impeller and extending from the lower portion of said impeller chamber into said discharge chamber, said wall being spaced from the impeller orbit and forming in the space between the latter and the adjacent end wall of said impeller chamber flow channels or passageways for the liquid leading into said discharge chamber.

3. A self-priming centrifugal pump having an impeller chamber, a rotatable impeller mounted therein, a separation and discharge chamber, and an arcuate wall spaced from the impeller orbit on the output side of the impeller forming on its inner and outer sides liquid flow paths having connection at their inner ends with the lower portion of said impeller chamber and communieating at their outer ends with said'separation and discharge chamber, whereby liquid from the impeller will separate and move proportionately in the paths in the same direction toward a point of discharge into said discharge chamber under conditions of balanced liquid density and pressure within and adjacent to said respective discharge paths, and will reverse the direction of fluid flow in one of said paths upon the unbalancing of said liquid density and pressure.

4. A centrifugal pump having a casing, an impeller therein, an elevated intake passageway connected to said casing, a separation and discharge chamber above said impeller, and a dividing member in said casin and spaced from its end wall and the impeller orbit opposite the output side of said impeller and defining a pair of volute passageways in overlapping relation to each other and to the impeller and in the plane of the latter, and connected at their upper ends with said discharge chamber, whereby outward liquid flow from said impeller casing to the discharge chamber will be divided over a portion of its travel under conditions of normal density of said liquid and will be reversed in the passageway most remote from said impeller under conditions of reduced fluid density within the impeller casing and the less remote liquid passageway, the blades of said impeller having a low tangential angle relative to the impeller orbit and arranged to coact with the liquid to discharge the same through both passageways under conditions of normal fluid density and to recirculate fluid through said pasageways under conditions of unbalanced density.

5. A centrifugal pump consisting of an impeller chamber, a discharge chamber in horizontal relation to said impeller chamber and having an outlet in its upper wall, a cut-off between said chambers, an intake extending downwardly and connected to said impeller chamber, and an arcuate dividing member in said impeller chamber spaced from the impeller orbit and extending from a position anterior to said cut-off in a direction toward the discharge chamber and providing outwardly of the impeller orbit a pair of inner and outer overlapping volute discharge passageways through which liquid will move from the impeller toward the discharge chamber under conditions of balanced liquid density and wherein the direction of liquid flow will be reversed in the outer passageway upon the unbalancing of the liquid density within said pump, the blades of said impeller having a low tangential angle relative to the impeller orbit and arranged to co-act with the liquid to discharge the same through both passageways under conditions Of balanced fluid density and to recirculate fluid through said passageways under conditions of unbalanced fluid density.

6. A self-priming pump consisting of a casing shaped to provide a volute impeller chamber at one end and a discharge chamber at its opposite end, one side wall of said casing between said chambers being provided with a cut-off, a rotatable impeller in said impeller chamber related to said cut-oil, an arcuate wall in said impeller chamber opposite the output side of said impeller and spaced from the end wall of said impeller chamber and the impeller orbit and extending from the lower portion of said impeller chamber into said discharge chamber in spaced relation to said cut-01f to form liquid flow passages for discharging liquid into said discharge chamber.

'7. In a centrifugal pump, a casing shaped to provide a chamber for an impeller and a discharge chamber, a cut-off at one side of said casing between said chambers, a rotatable impeller mounted in said impeller chamber related to said cut-off, said impeller chamber having a wall extending from said cut-ofl around said impeller in volute relation to its orbit to provide a liquid fiow space opening into said discharge chamber, and an arcuate wall in the flow space opposite the output side of said impeller, the inner portion of said wall being spaced from the impeller orbit and substantially concentric thereto and its outer portion extendin into said discharge chamber, said wall dividing the flow space into inner and outer passageways to provide for flow of liquid therethrough, to said discharge chamber under conditions of normal liquid density and pressure and reverse flow of liquid in the outer passageway responsive to an unbalance of liquid density and pressure.

8. A self-priming centrifugal pump having a rotatable impeller, a chamber therefor having an end wall in the plane of said impeller, an in-- take connected to said chamber, a discharge chamber above said impeller chamber, a cut-off adjacent one side of said discharge chamber, said end wall being of volute form and extending from said cut-oil to the opposite side of said discharge chamber and forming a flow space outwardly of the impeller orbit, and an arcuate wall in the flow space opposite the output side of said impeller and spaced from the impeller orbit and adjacent end wall of said impeller chamber to divide said flow space into inner and outer liquid flow passages communicatin at their outer ends with said discharge chamber.

9. In a centrifugal pump, a casing shaped to form at one end thereof an impeller chamber having an end wall and a separation and discharge chamber at the other end of said casing, a rotatable impeller mounted in said impeller chamber, and means in saidimpeller chamber and disposed substantially concentric to the output side of said impeller, and spaced from the impeller orbit and the adjacent portion of said end wall, to provide a pair of inner and outer paths outwardly of the impeller orbit for liquid flow toward said discharge chamber under balanced conditions of liquid density and pressure.

10. A centrifugal pump consisting of an impeller, a chamber therefor having a cut-01f and an end wall extending from said cut-on around and in spaced relation to the impeller orbit to form a flow space, and a dividing member in said flow space extending from a position anterior to the cut-oil in an arcuate direction toward the discharge chamber and providing a pair of inner and outer overlapping volute discharge passageways through which liquid will move from the impeller toward the discharge chamber under conditions of balanced liquid density and wherein the direction of liquid flow in the outer passageway will be reversed upon the unbalancing of the liquid density within the said pump.

11. In a centrifugal pump, the combination of an impeller chamber, an intake connected thereto, a discharge chamber having an outlet, said chambers being in connected relation, a cutoff at one side of and between said chambers, a rotatable impeller in said-impeller chamber having close clearance with said cut-off, said impeller chamber having an arcuate end wall in the plane of said impeller extending from said cut-oi! around said impeller and connected to the opposite side of said discharge chamber and forming a flow space contiguous to and outwardly of the impellenorbit, and an arcuate wall in said flow space extending from a point anterior to said cut-oil in the direction of rotation of said impeller into said discharge chamber and providing flow paths for the liquid, the direction of flow along the outer side of said wall being dependent on the density of the liquid supplied by said intake.

HERBERT E. RUPP.

REFERENCES CITED UNITED STATES PATENTS Number Name Date 1,908,635 La Bour May 9, 1933 1,966,896 La Bour July 17, 1934 2,002,454 Rupp May 21, 1935 45 2,073,733 Doty Mar. 16, 1937 2,110,883 La Bour Mar. 15, 1938

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