US 2997957 A
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Description (OCR text may contain errors)
1961 J. N. HALL ,997,957
MOTOR-DRIVEN PUMP Filed March 2, 1959 l 1 l lmllll HQ': 1 l I'll]:
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2,997,957 MOTOR-DRIVEN PUMP John N. Hall, Newark, Del., assignor to Enterprise Machine and Development Corporation, New Castle,
Del., a corporation of Delaware Filed Mar. 2, 1959, Ser. No. 796,302 12 Claims. (Cl. 103-87) This invention relates to a motor-driven, submerged pump and more particularly, relates to an economical structure for such a pump.
Various processing apparatus, for example, flushing or machine tool cooling systems incorporate means for pumping liquid through a conduit from a sump. These sump pumps are usually driven by electric motors; and they need not be extremely efficient in their use of the power supplied thereby because motors of practical size generally provide quite a bit more power than is required for pumping the rather small quantities of fluid required for flushing or cooling, for example. However, apparatus of this general type is sold in a highly competitive market, and it is, therefore, of great importance that the structure of the pump be as simple and economical as possible to permit the apparatus to be competitively priced.
An object of this invention is to provide a structure for a motor-driven submerged pump, which is simple and economical to manufacture and assemble.
In accordance with this invention, a thin-walled mounting tube, for example, made of commercially available tubular stock, extends downwardly from the motor into the sump. A hollow casing, for example, of inverted cupshape is inserted within the lower end of the tube and fastened therein against longitudinal movement. The motor shaft, or an extension thereof, for example, of sleeve form extends through a central passageway in the base of the cup into its interior, and an impeller blade is fastened to the end of this shaft extension. After the shaft and blade are inserted into the casing, the lower end is peripherally sealed by an annular plate which is secured to the lower end of the casing, for example, by a spring reacting aaginst the lower end of the mounting tube. This annular plate provides a central inlet opening into the casing and confines pressures created in the outer periphery.
A discharge tube extends from a portion of the outer periphery of the casing in line with the impeller blade for carrying liquid under pressure away from the pump. The casing or cup and discharge tube may be molded in one piece of a plastic material; and they may, for example, be connected to a substantially rigid discharge conduit by inserting it within the discharge tube and clamping the discharge about it to seal the connection.
The discharge tube may be inserted through a slot in the end of the mounting tube, and the cup may be longitudinally anchored within the mounting tube by a resilient bar inserted within the end of the mounting tube which bears against one surface of the casing and forces it into contact with a circular indentation formed in the wall of the mounting tube.
Novel features and advantages of the present invention will become apparent to one skilled in the art from a reading of the following description in conjunction with the accompanying drawings in which similar reference characters refer to similar parts and in which:
FIG. 1 is a view in elevation partially broken away in cross-section of one embodiment of this invention;
FIG. 2. is a view in elevation of a portion of the embodiment shown in FIG. 1; and
FIGS. 3, 4 and are cross-sectional views respectively taken through FIG. 1 along the lines 33, 4-4, and 5-5, and looking in the direction of the arrows.
In FIG. 1 is shown a motor-driven pump 10, for ex ample, incorporating a fractional horespower electric motor 12 and a pump 14 submerged within a tank of liquid 16. This arrangement is, for example, utilized in an apparatus for cleaning machine parts, such as gears and screws, of grease and foreign matter such as dirt or metal chips. Liquid 16 is, for example, a solvent, such as kerosene. Motor 12 is mounted, for example, upon a horizontal plate 18 and a thin-walled tube 20 for con necting pump 14 to motor 12 extends downwardly from motor 12 through plate 18, a predetermined depth into liquid 16. Tube 20 is fastened to motor 12, for example, by spade bolt and nut assemblies 22.
Thin-walled tube 20 is, for example, made of a standard commercially-available tubing stock, for example, two-inch O.D. brass tubing having a wall thickness of of an inch. A hollow casing 24, for example, formed as an inverted cup is inserted within the lower end of tube 20 and restrained against vertical or longitudinal movement relative to tube 20 by a circular indentation 26 formed in the wall of tube 20. The outside diameter of casing 24 is constructed and arranged to fit snugly within the inside diameter of tubing stock 20. However, care is taken to insure that the diameter is not large enough to interfere with insertion of casing 24 within the end of tube 20.
Casing 24, is for example, integrally formed in one piece together with a discharge tube 28. These parts are formed as a unit designated by reference character 30, for example, by molding them of a plastic material, for example, a linear polyethylene. Use of a plastic material not only facilitates manufacture, but also aids in connecting the pump to the discharge piping 32 as is later described in detail. Cup 24 also includes a central passageway 34 in its base through which extended motor shaft 36 passes into the interior 39 of cup 24.
Extended shaft 36 includes, for example, a solid motor shaft 38 directly connected to motor 12 and a sleeve 40 which is slipped over shaft 38 and conveniently secured thereto, for example, by force fitting. Force fitting provides a joint which is strong enough to transmit the relatively slight forces developed in pumping through the shaft.
An impeller blade 42 is secured to the end of sleeve 40 disposed within interior 39 of casing 24, for example, by insertion within a slot (not shown), and a pin 44 extends through sleeve 40 and blade 42. Blade 42 is, for example, a rectangular sheet of metal, for example, a sheet of 4, inch thick half-hard brass to provide corrosion resistance. Sleeve 40 is, for example, made of brass tubing stock to minimize corroslon.
An annular plate 46 is held in contact with the lower or open end of cup 24 to confine pressures created in the peripheral portions of the cup by impeller blade 42 to the vicinity of discharge tube 28. Hole 48 is provided in the center of plate 46 for allowing a supply of inlet liquid to enter casing 24. A sheet 50 of screen material, for example, a disc of brass 30 x 30 mesh screen formed of 0.013 diameter wire is held in contact with the lower surface of plate 46 which also may be made of brass for intercepting particles of foreign matter, such as metal chips and filings to prevent them from entering casing 24.
Casing 24, annular plate 46 and screen 50 are, for example, held within the lower end of mounting tube 20 by a resilient bar 52, shown in detail in FIGS. 2 and 3, which for example, is connected to tube 20 by insertion through holes 54 in its wall. Resilient bar 52 is, for example, made of a serpentine piece of spring material, for example, inch stainless spring steel wire; and its extended area formed by central convolutions 56 presses against the lower surface of screen disc 50 to maintain, in conjunction With circular indentation 26, the entire pump stantially rigid discharge conduit 32, for example, formed.
of conventional A inch O.D. copper tubing stock by having end 58 of conduit 32 inserted within a recess 60 in the end of discharge tube 28. A clamp 62, for example, a resilient clamp similar in form to an automobile radiator hose clamp is inserted over the end of discharge tube 28 and causes the inner surface of recess 60 to firmly embrace the outer surface of conduit 32. The plastic nature of the material forming cup 24 allows the force of clamp 62 to mold it to the outer surface of conduit 32 and provide a pressure-tight seal about it.
The structure of motor pump is not only economical to manufacture as indicated by its utilization of major parts of standard stock materials, but it is also simple to assemble. After shaft 36 and impeller blade 42 are assembled within interior 39 of casing 24, it is a simple matter to secure casing 24, annular plate 46 and screen 50 in operative position by simple insertion of spring bar 52 within holes in tube 20.
- An auxiliary inlet 64 is, for example, provided in the wall of tube and the flow through it is filtered, for example, by a screen 66 of a material similar to screen 50. Inlet 64 is used, for example, when a double suction to casing 24 through passageway 34, as well as through bottom hole 48, is desired. This double suction may be advantageous where extremely dirty liquids are being pumped and the inlet screens tend to rapidly become blocked with solid matter or gum deposits. However, inlet 64 is not required since a sufficient supply of inlet liquid is generally admitted through bottom hole 48.
I What is claimed is:
l. A motor-driven pump comprising a motor having an output shaft, a thin-walled mounting tube having an inside diameter considerably larger than the diameter of said shaft, one end of said mounting tube being connected to said motor and concentrically enclosing said shaft, a hollow casing inserted within the end of said mounting tube remote from said motor, said casing being disposed within the walls of said tube, projection means connecting said casing to said mounting tube for restraining longitudinal movement of said casing relative to said tube, the side of said casing adjacent said motor being cut out to provide a passageway through which said shaft extends into said casing, said shaft extending into said casing through said passageway, an impeller blade mounted upon said shaft within said casing, said casing being cut out along its axis to provide an inlet which allows fluid to enter said casing, and a discharge conduit connected to the outer periphery of said casing substantially in line with said impeller blade.
2. A pump as set forth in claim 1 wherein said hollow casing is shaped in the form of an inverted cup, said shaft extends through a relatively larger hole in the base of said cup, and an annular plate is secured to the open end of said cup to provide a central inlet and to confine pressures 4 created in its outer periphery to the vicinity of said discharge conduit.
3. A pump as set forth in claim 2 wherein said hollow casing incorporates a discharge tube extending laterally therefrom, a portion of the end of the mounting tube remote from said motor being cut out to provide a slot, and said discharge tube extends through said slot when said hollow casing. is insertedwithin said mounting tube.
4. A pump as set forth in claim 2 wherein said hollow casing and discharge tube are molded in one piece of a plastic material.
5. A pump as set forth in claim 1 wherein a circumferential indentation is formed in the wall of said mounting tube, and an upper surface of said hollow casing bears against said indentation which helps restrain its longitudinal movement.
6. A pump as set forth in claim 5 wherein a resilient bar is engaged Within the end of said mounting tube adjacent the end of said hollow casing remote from said inentation, and said resilient bar bears against the end of said hollow casing for maintaining it in cooperation with said indentation locked against longitudinal movement relative to said mounting tube.
7. A pump as set forth in claim 6 wherein an annular plate and a sheet of screen material are inserted between the end of said casing and said resilient bar for respectively defining an inlet opening to said casing and preventing larger particles of foreign material from flowing through it.
8. A pump as set forth in claim 7 wherein said output shaft comprises a solid shaft connected to said motor, and a sleeve is slipped over the end of said solid shaft and fastened thereto, and the end of said sleeve remote from said motor extends into said hollow casing.
9. A pump as set forth in claim 8 wherein said hollow sleeve is secured to said solid shaft by force fitting it thereto.
10. A pump as set forth in claim 8 wherein the end of said sleeve inserted within said casing is slotted, and an impeller blade is inserted within said slotted end and fastened thereto.
11. A pump as set forth in claim 10 wherein said impeller blade is a rectangular sheet of substantially rigid material.
12. A pump as set forth in claim 1 wherein the side wall of said mounting tube above said casing is cut out to provide a means for channeling fluid through said passage way into said casing.
References Cited in the file of this patent UNITED STATES PATENTS 1,801,103 Mummert Apr. 14, 1931 2,230,051 Conklin Jan. 28, 1941 2,468,704 Pippin Apr. 26, 1949 2,784,673 Namur Mar. 12, 1957 2,791,967 Klauss May 14, 1957 2,872,084 Edwards Feb. 3, 1959