US 3610416 A
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Description (OCR text may contain errors)
United States Patent  lnventor Walter J. Otto Wantagh, N.Y.
 Appl. No. 852,252
 Filed Aug. 22, 1969  Patented Oct. 5, 1971  Assignee Julius L. Englesberg Rockville Centre, N.Y.
54 PUMP FOR LIQUIDS 7 Claims, 2 Drawing Figs.
 US. Cl 210/121, 210/169, 210/416,415/l00  Int. Cl ..B0ld 35/26, BOld 35/02  Field of Search 417/424; 415/100,131,88;210/l2l,416,167,169, 172, 152, 251
 References Cited UNITED STATES PATENTS 2,106,600 1/1938 Hepler 415/100 X Primary ExaminerF rank A. Spear, Jr. Att0rneyBreitenfeld & Levine ABSTRACT: The pump includes a body having two inlets, arranged one above the other, and an outlet. A pair of spacedapart impellers rotate within the body between the two inlets and draw liquid into the body through the two inlets, respectively, and discharge the liquid through the outlet. Surface liquid flows over an annular float into the upper inlet. The body is formed of two telescoping parts adjustable so that one of the inlets may be closed. Top and bottom walls within the body define an impeller chamber, and the upper impeller is located closer to the top wall than the spacing between the lower impeller and the bottom wall, so that the upper impeller develops a higher pressure than the lower impellerv PUMP FOR LIQUIDS The invention relates to centrifugal pumps, and more particularly to such a pump including two impellers on a single shaft for simultaneously moving liquid in two different directions through the pump body.
It is an object of this invention to provide a pump capable, when immersed in a body of liquid, of simultaneously (a) pumping liquid from below the liquid surface, and (b) skimming liquid from the surface of the body. Advantageously, the pump is associated with a filter so that matter suspended in the liquid body as well as floating particles can be filtered out.
It is another object of the invention to provide such a pump which can be adjusted to pump only liquid from below the surface.
It is a further object of the invention to provide such a pump in which no seal is required around the shaft which carries the two impellers.
It is an additional object of the invention to provide a compact pump,, skimmer and filter unit which can be accommodated within the small space allocated in industrial electroplating vessels.
Additional objects and features of the invention will be apparent from the following description in which reference is made to the accompanying drawings.
In the drawings:
FIG. 1 is a vertical cross-sectional view through a pump and filter arrangement according to the present invention, the pump being adjusted for pumping liquid both on and below the surface; and
FIG. 2 is a vertical cross-sectional view of a portion of the pump adjusted to pump only liquid below the surface.
The pump chosen to illustrate the present invention includes a lower pump body section and an upper pump body section 11 telescopically arranged within the lower section 10. Two O-ring seals 9 surround section 1 1, only one of these seals being in use in the FIG. 1 position. The upper body section 11 is formed at its upper end with a flange 12 upon which an electric motor 13, for driving the pump, is seated. In the adjusted position shown in FIG. 1, the flange 12 rests on a positioning ring 14 which in turn rests on a support plate 15, the section 11 passing through an opening in the plate. The plate 15 is adapted to be mounted on the vessel (not shown) containing the liquid to be pumped and filtered, in such a way that the pump body 10, 11 is partially immersed below the liquid surface 116. The pump body and motor are fixed to the plate 15 by screws 17 (one shown in FIG. 1) passing through holes in plate 15, ring 14, and flange 12, and threaded into the base of motor 13.
Within lower pump body section 10 is an impeller cavity 20 defined at its lower end by the bottom wall 21 of section 10, and at its upper end by the bottom wall 22 of section 11. The pump body is furnished with two inlets, the lower inlet 23 being in the center of wall 21. Inlet 23 is shown carrying an adapter 24 for connection to a hose (not shown). The hose is used when it is desired to mount the pump outside the liquidcontaining vessel, in which case the free end of the hose is placed in the liquid. The upper inlet comprises apertures 25 in the sidewall of upper body section 11, the apertures being spaced above the bottom wall 22. In the position of FIG. 1, the inlet apertures 25 are outside the lower body section 10. Adjacent to bottom wall 21, the sidewall of body section 10 is formed with an outlet 26.
Fixed to the motor shaft 29 is the upper end of an impeller shaft 30, the lower end of which passes through an opening 31 in the wall 22 and into the impeller cavity 20. Within the cavity 26 are two impellers 32 and 33, which may be identical, both fixed to the impeller shaft 30. Impeller 32, at the lower end of shaft 30, is arranged when rotated to draw liquid in through inlet 23 and deliver it to outlet 26. Impeller 33, spaced above impeller 32, has a reverse orientation with respect to the latter impeller, and hence draws liquid in through inlet 25, via opening 31. Upper impeller 33 is spaced closer to top wall 22 ofthe impeller cavity 20 than the spacing between lower impeller 32 and the bottom wall 21. Consequently, impeller 33 develops a higher pressure than impeller 32, and the liquid drawn through inlet 25 by impeller 33 is forced through outlet 26 together with the flow from inlet 23.
An annular float 36 having a depending skirt 37 surrounds the region of the pump body having the inlet apertures 25. The internal diameter of the float is only slightly larger than the external diameter of body section 10, so that the float is free to move longitudinally with respect to the pump body. In practice, the inlet apertures 25 are located below the liquid surface 16, but the float 36 insures that the bulk of the liquid entering apertures 25 flows over the top of the float, i.e., the float 36 serves as a skimmer. Furthermore, since the float is free to move vertically with respect to the pump body, it continues to serve its skimming function regardless of minor variations in the liquid level.
In the present illustration, outlet 26 is connected by a short length of tubing 38 to the inlet 39 of a filter chamber 40. The filter chamber is supported by plate 15. Within the chamber 40, a filter tube 41 rests on an annular ridge 42 projecting from the chamber bottom wall 43. A similar ridge 44 presented by the chamber cover 45 presses against the upper end of the filter tube 41. The cover 45 and chamber 40 are locked together by a stem 46, the lower end of which is threaded into the bottom wall 43, and the threaded upper end of which carries an internally threaded knob 48. Cover 45 is formed with an outlet 47 which may communicate, by means of suitable tubing (not shown), with the liquid-carrying vessel, so that filtered liquid is returned to the vessel. It will be noted that inlet 39 communicates with the annular space surrounding filter tube 41, and outlet 47 communicates with the annuiar space within the filter tube. Thus, liquid is forced to flow through the filter tube before leaving chamber 40.
In operation, rotation of impeller shaft 30 by motor 13 causes rotation of impellers 32 and 33 within cavity 20. Impeller 32 draws liquid, including undesirable particles suspended in the liquid, through inlet 23 and discharges it through outlet 26. At the same time, due to the action of impeller 33, liquid and floating particles are skimmed off the sur face of the liquid. The surface liquid flows over the top of float 36, through inlet apertures 25, opening 31, and chamber 20 to outlet 26. The mixture of surface liquid, floating particles, below surface liquid, and suspended particles leaving outlet 26 flows through filter chamber 40, during which flow the particles are caught by filter tube 41. As a result, only filtered liquid leaves chamber 40 through outlet 47. It should be mentioned that since impeller 33 operates to drive liquid downwardly, no seal is needed between the impeller shaft 30 and the pump body, since the action of impeller 33 prevents flow of liquid up the shaft.
The pump of the present invention is so conceived that it may be adjusted, when desired, to pump below-surface liquid without skimming the surface of the liquid. The pump body is shown in FIG. 2 after such an adjustment. The adjustment is made by removing screws 17 and withdrawing positioning ring 14 from beneath flange 12. If the ring is made in two halves, they are simply withdrawn laterally. If the ring is whole, the assembly of motor 13 and body section 11 is lifted upwardly, bring impellers 32 and 33 with it, and ring 14 is simply slipped downwardly past the impellers for removal. The body section 11 is then replaced, as shown in FIG. 2. Since body section 10 remains in the same location it occupies in FIG. 1, removal of ring 14 causes the body section 11 to move further into section 10 before flange 12 comes to rest on support plate 15, whereupon screws 17 once again secure section 11 and motor 13 to the plate. Inlet apertures 25 are now located within section 10, with seals 9 on both sides of it, so that these apertures will not longer function as inlets to the pump body. Of course, the annular float 36 is also not used, since no skimming is to be performed.
In the arrangement of FIG. 2, impeller 32 serves the same purpose as it does in the FIG. I arrangement. In addition,
although impeller 33 no longer serves to skim the liquid surface, it is not without function. Some liquid flows around the peripheral edge of impeller 32 and into the space between the impellers. Ordinarily this liquid would tend to travel up rotating shaft 30, and hence a seal would be provided around the shaft, perhaps between the shaft and the sidewall of opening 31. However, due to the presence of impeller 33, which as mentioned above develops a higher pressure than impeller 32, no such seal is needed, since impeller 33 constantly urges the liquid which fills the cavity 20 downwardly, so that no liquid ever reaches the opening 31.
The spacing between impellers 32 and 33 is also important, since it allows a column of liquid to exist between the impellers. Impeller 33, during its rotation, tends to suck air into the pump body, and if the blades of impeller 33 were simply mounted on the upper face of impeller 32, or if impellers 32 and 33 were arranged back to back, this air might be forced past the edge of impeller 32 and into outlet 26, especially since impeller 33 develops a higher pressure than impeller 32. However, the column of liquid between the impellers, within cavity 20, serves as a trap to prevent air from reaching impeller 32.
The invention has been shown and described in preferred form only, and by way of example, and it is understood, therefore, that many variations may be made in the invention which will still be comprised within its spirit.
What is claimed is:
l. A pump for liquids comprising:
a. a pump body having upper and lower inlets arranged one above the other, and an outlet,
b. top and bottom walls within said body defining an impeller chamber communicating with said inlets and outlet, said lower inlet being in said bottom wall and said top wall having an opening communicating with said upper inlet,
c. an impeller shaft extending into said body through said opening,
means for rotating said shaft, and
e. an upper and a lower impeller fixed to and rotatable with said shaft, said impellers being located within said chamber between said two inlets, said outlet being between said lower impeller and said bottom wall, said lower and upper impellers when rotated drawing liquid in through said lower and upper inlets, respectively, moving the liquid in opposite directions through said chamber, and discharging the liquid through said outlet,
whereby said upper impeller serves to both move liquid from said upper inlet to said outlet and prevent flow of liquid from said chamber upwardly along said shaft. 2. A pump as defined in claim 1, including a filter commu- 5 nicating with said outlet.
3. A pump as defined in claim 1, including an annular float surrounding the portion of said pump body having the upper of said inlets, surface liquid flowing over said float to said upper inlet.
4. A pump as defined in claim 1, wherein said pump body is formed of two telescoping parts, one of said inlets being formed in each of said parts, the inner of said parts being movable into the outer of said parts to close one of said inlets.
5. A pump as defined in claim 1, wherein the upper of said impellers is spaced closer to said top wall than the spacing between the lower impeller and said bottom wall.
6. A pump as defined in claim 5, wherein the upper of said inlets is located above said top wall, said upper inlet communicating with said chamber via said opening.
7. A pump for liquids comprising:
a. a pump body having an inlet and an outlet;
b. first and second walls within said body defining an impeller chamber communicating with said inlet and outlet, said inlet being in said first wall, an impeller shaft extending into said chamber through an opening in said second wall,
d. meansforrotatingsaid shaft,and e. first and second independent impellers within said chamber and fixed to and rotatable with said shaft, said impellers being spaced apart along the length of said shaft, said first impeller being spaced relatively far from said first wall but said first impeller being closer to both said inlet and outlet than said second impeller and serving to draw liquid through said inlet and discharge liquid through said outlet, said impellers being arranged so that most of the liquid moves through only said first impeller as it flows from said inlet to said outlet and said second impeller being spaced relatively close to said second wall and urging liquid toward said outlet in a direction opposite to the direction in which said first impeller moves liquid, thereby preventing any liquid from moving through said opening from said chamber,
the space between said impellers being filled with liquid which serves to prevent air, entering said chamber through said opening, from reaching said outlet.