US 3048118 A
Abstract available in
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Description (OCR text may contain errors)
Aug. 7, 1962 c. J. ERD 3,048,118
Filed Feb. l0, 1961 2 Sheets-Sheet l FIGZ.
Aug- 7, 1962 c. J. ERD 3,048,118
Filed Feb. l0, 1961 2 Sheets-Sheet 2 7l 55 /9 69 8' TI Fl@ 3 9 93 75 ,03 v9 Y J J u ffl/2 94 7\ A7 73; lll 109 m 9 L e5 fof w o o fc5 99 j H9 J 4l 37 27 3l i? 745 29 5 45\ 42 44 43 33 5i @mA/ZM 9* SW/LJ J M4 OD 4 F49 United States Patent C) Mig PUMP Charies J. Erd, St. Louis, Mo., assigner to Chas. S. Lewis & Company, Incorporated, St. Louis, Mo., a corporation of Missouri Filed Feb. l0, 1961, Ser.. No. 83,477 13 Claims. (Cl. 10S-87) This invention relates to pumps, and with regard to certain more specific features, to pumps of the immersed type.
Among the several objects of the invention may be noted the provision yof a centrifugal pump adapted successfully to pump corrosive, abrasive and like deleterious or dangerous liquids, including slurries; the provision of a pump of the class described which is constructed to prevent entry into its seals and bearings of such liquids and their vapors and gases; the provision of a pump ott this class in which its sealing means are not only effectively protected `from contact with the deleterious liquid being pumped, but are efiiciently lubricated; and the provision of a pump of .this class adapted to operate for long periods Without the need for close attention or disassembly for major replacements. Other objects and features will be in part apparent and in part pointed out hereinafter.
The invention accordingly comprises the elements and combinations of elements, features of construction, and arrangements of parts which will be exempliiied in the .structures hereinafter described, and the scope of which will be indicated in the following claims.
In the accompanying drawings, in which one of various possible embodiments of the invention is illustrated,
FIG. 1 is a side elevation illustrating a complete pump assembly made according to the invention;
FIG. 2 is a horizontal cross section taken on line 2--2 of FIG. l;
FIG. 3 is an enlarged vertical and axial section of the pump assembly, the driving motor of the vassembly being omitted and mid portions of an upper barrel being cut away;
FIG. 4 is an enlarged detail cross section of an upper running seal; and
FIG. 5 is an enlarged detail cross section of a lower running seal.
Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.
In the chemical industry are many corrosive, abrasive and dangerous liquids required to be pumped, such as, for example, sulfuric acid. These are usually damaging to the pumping apparatus and particularly 4to the running seals required. The difficulties are increased when such liquids are mixed with materials that form abrasive slurries. For example, in the production of chemical fertiliz ers, sulfuric acid is mixed with powdered phosphate rock, in order to produce a slurry from which accrues phosphoric acid. The slurry is not only corrosive but also highly abrasive and very damaging to running seals and the like. In order to describe the invention, apparatus is illustrated which will successfully pump such -a slurry which results `from mixing sulfuric acid, phosphoric acid and powdered phosphate rock and in connection with which several corrosive gases are liberated.
Referring now more particularly to the drawings, FIGS.
Eidl hatented Aug. 7, 1962 perforate barrel il. The barrel l1 is supported on the plate 7 by means of a bolted flange 13 surrounding the opening 9, and is ribbed for strength as shown at 15. On the flange i3 is a bolted flange i7 of a motor-supporting pylon shown at i9. The pylon has an upper flange 2l to which is bolted a vertically disposed driving motor 23.
Bolted to the lower end of the upper barrel 11 is an imperforate lower barrel v25. The lower end of barrel 25 has a flaring extension 27 terminated by a lower flange 29. In the lextension 27 are one or more outlets, one of which is shown for example at 31 (FIG. 3). Above the extension 27 is an inward fiange 33 in which is bolted a downwardly converging nozzle-forming ring 35. The resulting inside converging nozzle is lettered 37. The outside 39 of ring 35 forms an upwardly flaring abrasiveresistant deflecting surface, part of which forms a ton-gue 4l extending out through the opening 3l. In the case that `several openings Si are used, a tongue such as 41 extends from each.
Attached to the flange 29 is one wall 42 of a centrifugal pump casing 43. The pump as a whole is lettered 45. The casing d3 has the usual volute or scroll fonn generally used in centrifugal pumps. Bolted to the bottom of the casing is a removable pump wall 47 forming also a ared inlet 49. The impeller of the centrifugal pump 45 is shown at Si. lts blades are indicated at 53.
T he impeller 51 is keyed to a shaft 55, being additionally held by a nut 57 of streamlined exterior form and located in the inlet 4%. Attached with a force fit -to the hub of the impeller Si is a removable impeller ring 52. Attached with a force ht to the casing 43 is a removable casing ring 44. Rings d4 and 52 are composed of corrosionand wear-resistant materials, but they are not intended to maintain a leakless fit at their cylindrical interface. Consequently they may wear to a condition of wide clearance without requiring frequent renewal. The cylindrical interface between the rings i4 and 52 is concentric with, but of a diameter greater than, the smallest outside diameter of ythe nozzle-forming ring 35, so that eiliux of any leakage from between rings 44 and 52 will occur as indicated by the darts a, adapted for radial deilection along the outside curved surface 39 of ring 35. Since it is contemplated that an abrasive slurry is to be handled, the material of the ring 35 is preferably made abrasive-resistant, as well as corrosion-resistant.
The outlet of the scroll 43 is connected (FIG. 1) through an elbow 59 with a riser pipe 6l, the upper end of which passes through an appropriate opening in the plate 7, by being held in position by a clamp and sealing means 63. As shown at 65, the upper end of the riser pipe el is flanged for attachment to apparatus which is to receive .the pompage.
The shaft 55 extends upward ltlirough both barrels 25 and 11. Its upper end is attached to .the motor shaft by means of a coupling 67. The top of the upper barrel 11 is enclosed by a head 69. Attached to the upper end of the shaft and passing through the head is a sleeve 71, between which and the barrel 11 is located an antifriction bearing '73, adapted to resist both radial and axial thrust. The sleeve '7l above bearing 73 is formed with a shoulder 7S. This supports a wear ring '77 (FIG. 4), frictionally held by a rubber ring '79 to rotate with shaft 55. The ring '77 `forms part of a cartridge seal, indicated generally by the number `til.. This includes (FIG. 4) a jacket 83 within which is a second stationary wear ring 85, sealed to the jacket by la resilient boot 87. A spring-pressed ring S9 holds the boot 87 against the stationary ring 85. The pressure springs are indicated at 91.
A-t numeral 93 is shown an inlet for air or other gas lmder pressure. Hereinafter air will be referred to as one of the appropriate gases. This communicates with a spaans purge pipe 95, extending from the top of the barrel 11 and down through its lower end and into the barrel 25. Attached to the gas inlet 93 is an air pressure inlet pipe 94, leading from suitable air compressing means. Connected with this pipe 94 is an inlet check valve 96 which permits flow from the compressing means to the purge pipe 95, assuming that a suitable pressure is maintained by the compressing means for `the purpose. Valve 96 will close and prevent reverse ow if the pressure supplied by the compressing means falls below the pressure in pipe 95. At numeral 191 is shown an oil pipe, which extends from an upper passage 193 down to lower oil feed passages 105 and 125. Oil return passages are shown at 107. The upper passage 103 communicates with the top of the bearing 733 and the underside of the cartridge seal 31. A sight gl-ass assembly 111 closes oil port 1119 allowing for visual -inspection of the oil flow by means of a glass `disc 112.
Bolted to the underside of the lower flange 99 of barrel 11, and located Within the barrel 25, is a cap 113. This also holds a stationary diaphragm ring 115 in place against the bottom of llange 99. Attached to the mid portion of the shaft 55 isa sleeve 117, -between which and the flange portion 99 of barrel 11 is located an antifriction, radialthrust bearing 119. The lower portion of the sleeve 117 is constructed as a centrifugal oil impeller having a running t in the diaphragm 115 and having formed therein angled passages 121. The inlets of these passages above diaphragm 115 are axially directed and the lower outlets below diaphragm 115 are radially directed, so that upon rotation they will draw down oil from a supply 123 in barrel 11, and produce oil pressure in the cap 113. Oil is thus forced through angled passages 125 and passage 105 to the oil pipe 191 in which the head pressure establishes in cap 113 a pressure which is in excess of the head pressure of -oil which is carried to the level shown in `barrel 11. Moreover, a circulation is established from the inside of the barrel 11, rotating passages 121, passages 125, 105, pipe 191 and passage 1013 to the top of bearing 73 and back to the barrel 11. Thus bearing 73 is lubricated by a cascade of oil down through it for return to the oil supply 123 in barrel 11. Bearing 119 is lubricated by immersion in this oil supply 123. Hereinafter, the lower end of the sleeve 117, including its passages 121, may be referred to in general as a centrifugal oil pump, `and as such it is numbered 127.
The oil pressure established by the centrifugal oil pump 127 acting against the hydraulic head in pipe 1411 is used to force oil through a running seal between shaft 55 and the cap 113. The seal is constituted by a yceramic ring 129, located in a recess at the bottom of the cap 113 and held stationary by a resilient O-ring 131 (FIG. 5). At numeral 133 is shown a carbon sealing ring which is held to the shaft 55 by an O-ring 135. Above the carbon ring 133 is a washer 137 upon which presses a spring 139. Spring 139 is located in an inverted cup 141, attached by fasteners 143 .to the lower end of the oil pump 127. The cup 141 surrounds the spring 139 and also contains the upper end of the carbon ring 133. The running seal provided between the ceramic ring 129 and the carbon ring 133 is disposed in a radial plane, and is therefore substantially unaffected as to leakage by any whip that may occur in the shaft 55.
Lubrication for the seal is provided by the pressure in the cap 113, this pressure being greater than that which could be supplied by the level 123 of oil carried in barrel 11, as above explained. Thus it will be seen that a pressure dilerential is established across the sliding interface between rings 129 and 133 from the oil-filled inside of cap 113 to the inside of barrel 25. This will transport a small amount of oil across the interface-for lubrication. The pressure differential in the direction described prevents any gas or vapor from moving from the inside of barrel 25 into the seal 129, 133.
Operation is as follows:
First, it is assumed that the upper barrel 11 has been suitably filled with oil to level 123, and that air under pressure is supplied to the inlet 93 at sufcient pressure to prevent establishment of a liquid level in the barrel 25. in other words, the air pressure in barrel 25 is suicient that the barrel acts as an air trap. Preferably, sufficient air is supplied so that it will bubble outward through the nozzle 37, as indicated at the darts 145. This air ultimately escapes by bubbling up through the slurry 3 to escape at level 5.
Upon exciting the motor 23, shaft 55 is rotated, thus operating the centrifugal oil pump 127 and the main centrifugal pump 45. The latter draws in the slurry of acid and abrasive through the inlet 49, expelling it through the casing 43 .and riser pipe 61. Pressure established for this purpose in the casing of pump 45 will produce some leakage through the cylindrical interface between the rings 4d and 52. This leakage is deflected by the outside deflector surface of the nozzle ring 35 and into the main body of the slurry. Air under pressure within-the barrel, escaping at the nozzle 37, prevents any of this material from entering the barrel 25. Thus the head pressure of the slurry 3 in the sump 1 is prevented from establishing any level of slurry in the barrel 25, which might reach the seal 129, 133. Moreover, by preventing the establishment of a level of slurry at any level in the barrel 25 and maintaining a downward How of air, there is minimized the chance of access to the seal 129, 133 of any corrosive gases or vapors. These are substantially blocked from entry through the nozzle 37 into barrel 25.
The centrifugal oil pump 127, in addition to furnishing circulating oil for the upper bearing 73, furnishes a pressure differential across the seal 129, 133 which prevents air from escaping from the barrel 25 at the seal. It also prevents any contaminating gases or vapors (which might enter the nozzle 37 under unusual conditions) from reaching the running interface of the seal 129, 133. For example such small amounts might enter under conditions of low liquid level in sump 3 with violent agitation within the member 27. it is to be understood, however, that under conditions of loss of air pressure in the barrel 25, some low liquid level might be carried in the barrel 25 (below level 5 in the sump 1), the `barrel 25 then acting purely as a diving bell. Under such conditions, some but not all of the advantages of the invention would accrue, the chief one being the prevention of the rise in barrel 25 of a liquid level to the seal 129, 133, because outward air movement up pipe is checked by the action of check valve 9e.
Under any operating conditions, the small amount of oil that may escape through seal 129, 133 from the upper 'barrel 11 into the lower barrel 25 and pass out of the nozzle 37 is so small as to be inconsequential .as a contaminant in the slurry.
In view of the above, it will be seen that the several objects of the invention are achieved and otheradvantageous results attained.
As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.
1. A pump assembly for use in a liquid sump comprising an imperforate barrel adapted for upright location in the liquid, a shaft extending through said barrel, rotary sealing means between the shaft and an upper portion connected to said barrel, driving means for said shaft above said sealing means, a centrifugal pump having an impeller attached to said shaft below said barrel and also having a casing around the impeller, connecting means between said barrel and said casing, said connecting means having at least one opening exposed to movespaans ment therethrough of fluid in said sump, said barrel having lower end outlet means in communication with the sump through said opening, a second barrel extending upward from said first-named barrel and having an upper bearing for said shaft and a lower bearing therefor, said upper barrel being adapted to form an oil sump, means located at the upper end of the first-named barrel and forming a pressure chamber around said rotary seal for the shaft, 'and shaft-driven oil pump means having an inlet connection with the upper barrel .and an outlet in said pressure chamber and adapted to produce a pressure differential across the seal from said pressure chamber tcsaid first-named barrel.
2. A pump assembly according to claim l, including an oil-head-pressure connection between said pressure chamber and the upper end of the upper barrel at a location above said upper bearing.
3. A pump assembly according to claim 2, wherein said oil pump means is of the centrifugal type having an impeller on said shaft where it passes through said pressure chamber.
4. A pump assembly for use in a liquid sump comprising an imperforate lower barrel adapted for upright location in the liquid and having an outlet at its lower end submerged below the liquid surface level, an upperend assembly above said barrel forming a chamber adapted to carry pressure in excess of the pressure in the barrel, an upper container on the lower barrel forming an oil sump, a shaft extending through said upper container, the lower barrel and said chamber, a seal between said assembly and the shaft separating said chamber from the space in the barrel, means above the upper container adapted lto rotate the shaft, bearing means in said upper container for said shaft and adapted to be lubricated by said oil, the lower end of said shaft extending downward from said lower outlet of the lower barrel, centrifugal oil pump means in said pressure chamber and driven by said shaft, said centrifugal oil pump means having oil inlet connecting means with the interior of the upper container below the surface level of the' oil therein and adapted to generate oil pressure at said seal and for circulation through said bearing means, a centrifugal pump having an impeller attached to said shaft below the lower barrel and also having a casing around the impeller, connecting means between the outlet of the lower barrel and said casing, said connecting means having `at least one opening exposed -to movement therethrough of -uid in said sump, said outlet being in communication with the sump through said opening.
5. A pump assembly for use in a liquid sump comprising an imperforate barrel adapted for upright location in lthe liquid, a shaft extending through said barrel, rotary sealing means between the shaft and an upper portion connected to said barrel, driving means for said shaft above said sealing means, a centrifugal pump having an impeller attached to said shaft below said barrel and also having a casing around the impeller, connecting means between said barrel and said casing, said connecting means having at least yone opening exposed to movement therethrough of iiuid in said sump, said barrel having lower end outlet means in communication with the sump through said opening, said impeller and said casing having an unsealed circular running clearance therebetween subject to an annular liquid iow of liquid therethrough from the inside of the casing to the sump, said lower end outlet means of the barrel being in the'shape of `a converging nozzle connected with the lower end of the barrel and having a circular end closely surrounding the shaft to form a comparatively narrow annular gas outlet, the
outside of said nozzle being shaped to form an outside converging deilecting surface in the path of said annular leakage flow to guide it radially away from said lower outlet of the barrel, and means adapted to introduce a gas under pressure into said barrel for annular flow from d said converging nozzle within the confinesv of said annular leakage ow.
6. A pump assembly for use in a liquid sump comprising an imperforate barrel adapted for upright location in the liquid, a shaft, bearing means at the upper end of the barrel for said shaft, said barrel having a lower outlet formed as a converging nozzle, said shaft extending through the barrel and out of said converging nozzle with an `annular space between them, means adapted to move air under pressure through the barrel and through said annular space, a centrifugal pump having a casing attached at the lower end of the barrel and an impeller `attached to said shaft, said impeller and said casing having beyond said nozzle an unsealed circular running clearance therebetween of an effective diameter greater than the outside diameter of said annular space, whereby eiux of leakage from the circular clearance is directed away from said annular space.
7. A pump assembly according to claim 6, wherein the outside of said converging nozzle is curved outwardly to a diameter .greater than `the outside `diameter of said unsealed running clearance for the deflection of leakage flow therefrom away from the annular outlet.
8. A pump assembiy for use in a liquid sump comprising an imperforate lower barrel adapted for upright location in the liquid and having an outiet at its lower end submerged below .the liquid surface level, said lower barrel having an upper-end assembly forming a chamber adapted to carry pressure in excess of the pressure in the barrel, an upper barrel extending from the lower barrel and forming `an oil sump at its bottom, a shaft extending through both barrels and said chamber, means above the upper barrel adapted to rotate the shaft, bearing means at the top and bottom of the upper barrel for said shaft, the bearing at the bottom being submerged in said oil, the lower end of said shaft extending downward from said lower outlet of the lower barrel, a centrifugal pump having an impeller attached to said shaft below the lower barrel and also having a casing around the impeller, connecting means between the outlet of the lower barrel and said casing, said connecting means having at least one opening exposed to movement therethrough of fluid in said sump, said outlet being in communication with the sump through said opening, centrifugal oil pump means in said pressure chamber and driven by said shaft, said centrifugal oil pump means having oil inlet connecting means with the interior `of the upper barrel below the surface level of the oil therein.
9. A pump assembly according to claim 8, including an oil-head-pressure connection between said pressure chamber and a location in the upper barrel above said upper bearing.
10. A pump assembly according to claim 9, including a gas pressure connection with said lower barrel.
ll. A pump assembly according to claim l0 wherein the oil-head-pressure in said oil-head-pressure connection is greater than the gas pressure in said lower barrel.
l2. A pump assembly according to claim l1, wherein said outlet of the lower barrel is formed as a converging nozzle inwardly to constrict gas ow annularly around the shaft.
13. A pump assembly according to claim l2, including an unsealed circular running clearance between the impeller and the casing subject to an annular leakage ow of liquid therefrom, the diameter of said clearance being larger than the outlet end of said nozzle, the outside surface of said nozzle adapted to form a deiector for said leakage ilow away from the gas outlet end of said nozzle.
References Cited in the le of this patent UNITED STATES PATENTS