US 2748668 A
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Description (OCR text may contain errors)
June 5, 1956 HORNBOSTEL 2,748,668
SEPARATOR-PUMPING OPERATION FOR PAPER STOCK Filed July 11, 1952 s Sheets-Sheet 1 IHVEUTUF: L/(iyd \fibzvzoszel June 5, 1956 HORNBOSTEL 2,748,658
sEPARATOR-PUMPING OPERATION FOR PAPER STOCK Filed July 11, 1952 5 Sheets-Sheet 5 Jfvvenfar Llgyd flortzosfl SEPARATOR-PUNIPING OPERATION FOR PAPER STOCK Lloyd Hornbostel, Beloit, Wis., assignor to Beloit Iron Works, a corporation of Wisconsin Application July 11, 1952, Serial No. 298,332
3 Claims. (Cl. 92-28) This invention relates to the pumping of fluids and the centrifugal separation of heavier impurities therefrom, and-more particularly, to a method of and apparatus for pumping paper machine stock and centrifugally separating heavier impurities therefrom.
As is well known in the art, the presence of an appreciable amount of even very small particles of impurities in the paper stock'may be harmful in the paper machine operation for a number of reasons, including interference with the pumps and the like used in transporting the stock from one point to another in a paper machine and the formation of defects in the web itself on the forming wire, or during subsequent dewatering operations. In view of the great variety of possible sources of impurities in the stock, these impurities include such materials as metal scraps and particles of inorganic materials such as sand. The present invention is concerned principally with the removal of those impurities which are heavier than the fluid medium in which they are borne. Such impurities in paper machine stock include the aforementioned metal particles and inorganic particles.
In the operation of paper machines heretofore, two general methods of removing impurities were employed. In general, the devices used for removing such impurities were positioned at the discharge of the fan pump and prior to the stock inlet to the headbox. One type of device used is a screen, which may be used to screen out particles larger than a predetermined minimum particle size which would pass through the screen. The screens, of course, ultimately accumulate a sufficient amount of impurities, so that the screens resist the passage of stock therethrough and must be removed and cleaned before being reinstalled.
Another type of device used for removing impurities from paper stock is generally referred to as the Vortrap, which employs the general principles of the centrifuge. In the Vortrap operation, the stock is pumped at a high rate of speed through a helically wound pipe in a downward direction so as to cause swirling or centrifugal motion in the stock, and the stock is released from the pipe into a chamber, wherein the impurities are urged against the wall and the impurity-free stock rises upwardly through the center of the chamber leaving the impurities behind. It will, of course, be appreciated that the rate of flow at which the stock is pumped into such a device must be very high, and the frictional losses are also very high, so that the rate of flow of stock departing from such a device is substantially reduced and additional pumping may be necessary. Also, by their very nature such devices can accommodate only a relatively small volume of stock flow and large batteries of these devices must be used in parallel in order to accommodate an appreciable amount of stock flow during the paper machine operation.
The instant invention provides a combination fluid pump and centrifuge, which not only separates the heavier impurities from the stock or the like fluid by the use United States Patent of centrifugal force, but also pumps the fluid by the use of centrifugal force, the necessary energy for imparting centrifugal force to the fluid for accomplishing both purposes being furnished by the rotation of a single rotor member.
My invention consists in an apparatus that is a fluid pump and centrifuge for separating heavier impurities from a fluid, that comprises-a casinghaving an axial inlet at one end thereof and two separate outlets at the other end thereof, a shaft extending into the casing, a rotor mounted on the shaft in the casing, blades mounted on the rotor arranged to centrifugally separate the heavier impurities from the fluid and to centrifugally pump the fluid from the axial inlet toward the outlets; one of the outlets is aligned with the radially outermost casing walls at the outlet end to receive the centrifugally separated impurities; and a draw-01f chamber is positioned below and in communication with that outlet to accommodate gravity flow of the impurities into the chamber. Means are also provided for selectively opening and closing the chamber to selectively permit and prevent flow 0f fluid therethrough to rinse out accumulated impurities therein.
It is, therefore, an important object of my invention to provide an improved apparatus for and method of pumping fluid and centrifugally separating heavier impurities therefrom.
It is another object of my invention to provide a fluid pump and centrifuge for separating heavier impurities from the fluid, comprising a casing havin a top axial inlet and two separate outlets at the bottom thereof, a shaft extending into said casing, a rotor mounted on said shaft in said casing, blades mounted on said rotor arranged to centrifugally separate the heavier impurities and to centrifugally pump the fluid downwardly toward said outlets, one of said outlets being adapted to discharge impurity-free fluid, the other of said outlets being arranged outwardly from the one to receive the centrifugally separated impurities, and draw-off means for said other outlet to selectively permit and prevent fluid flow therethrough.
It is a further object of my invention to provide an improved method of pumping fluid and centrifugally separating heavier impurities therefrom, which comprises swirling impurity-bearing fluid into a downwardly diverging annular stream having fast enough centrifugal speed to force the impurities outwardly and downwardly along the outer surfaces of the stream withdrawing impurityfree 'fluid from the inner side of the divergent annular stream and contacting the outer side of the divergent annular stream with-a substantially static body of fluid to permit the impurities to fall by gravity into the static fluid.
It is still another object of my invention to provide an improved fluid pump and centrifuge for separating heavier impurities from the fluid, comprising a casing having an axial inlet at one end thereof and separate uniplanar inner and outer concentric peripheral outlets at the other end thereof, a shaft extending into said casing, a rotor mounted on said shaft in said casing, blades mounted on said rotor arranged to centrifugally separate the heavier impurities from the fluid and to centrifugally pump the fiuid from the axial inlet toward the outlets, the inner outlet being adapted to discharge impurity-free fluid and the outer outlet being adapted to receive the centrifugally separated impurities.
It is still a further object of my invention to provide an improved fluid pump and centrifuge for separating heavier impurities from the fluid, which comprises an upwardlyapexed frusto-conical rotor, blades mounted on the rotor, slant walls to centrifugally separate impurities from the fluid and to centrifugally pump the fluid downwardly. and outwardly from the rotor, an annular partition wall positioned below and in substantial registry with the rotor base, and a discharge housing cooperating with the wall to define uniplanar concentric annular discharge chambers separated by said wall, the outer of such chambers being normally blocked and the inner being adapted to accommodate the discharge of impurity-free fluid.
Other objects, features and advantages of my invention will become apparent to those skilled in the art from the detailed description of a preferred embodiment thereof and the drawings illustrating this preferred embodiment.
On the drawings:
Figure l is a sectional elevational view of a separatorpump embodying my invention;
Figure 2 is a top sectional view taken substantially along the line IIII of Figure 1;
Figure 3 is a top plan view of the separate uniplanar concentric annular inner and outer outlets or discharge chambers of the separator pump of Figure 1, taken substantially along the line IIIIH of Figure 1;
Figure 4 is a top plan view of the rotor of the separator pump of Figure 1;
Figure 5 is a sectional elevational view of another embodiment of my invention;
Figure 6 is a bottom plan view taken along the line VI-VI of Figure 5; and
Figure 7 is a top plan view taken along the line VII-VII of Figure 5.
As shown on the drawings:
The reference numeral 10, as shown in Figure 1, designates generally the separator pump embodying the instant invention. The pump 10 has a drive shaft 11 suitably connected to means for driving the same (not shown), which may include any of the customary driving devices such as a motor and pulley arrangement attached to a sheave mounted on the shaft 11. The shaft 11 is mounted for rotation on bearings 12, preferably in a closed bearing assembly 12 which extends upwardly into a top bearing housing 13, in a structural arrangement for an overhung bearing support well known in the art.
The incoming stock flows into the inlet line 14, as shown by the arrow, and then into a generally annular inlet chamber 15, having the bearing assembly housing 13 mounted on the top thereof and being itself mounted on a generally circular plate 16. The bearing assembly housing, the inlet chamber 15 and the plate 16, as well as most of the remaining structural members are made of suitable structural materials such as steel or the like, and these members are secured to each other by means of nuts and bolts, or preferably, by means of welds in the manner well known in the art, which need not be discussed herein in detail.
The plate 16 is suitably apertured at 17 beneath the inlet chamber 15, so as to permit downward flow of stock from the inlet chamber 15 into a second inlet chamber designated generally at 18 which is defined by the top plate 16 and a bottom plate 19 spaced from the top plate 16 by means of an annular spacer 20. The stock flows through the apertures 17 and into the second inlet chamber 18 so that its flow is generally axially aligned with respect to the pump 10 and the drive shaft 11.
The pump entrance or eye 21 is an essentially annular aperture defined by an aperture in the bottom plate 19 which surrounds the shaft 11.
An upwardly-apexed generally frusto-conical casing member 22 supports from beneath the apertured plate 19 and extends divergingly downward from approximately the outer edges of the pump entrance 21, with which the small end of the frusto-conical casing member 22 is in registry, to a lower or base annular flange 23. As shown herein, the slant walls of the frusto-conical casing member 22 diverge very noticeably, but in other modifications of my apparatus, it may not be necessary to employ such a distinct divergence. In fact, if the impurities are substantially heavier than the fluid bearing them, it may be possible to use substantially vertical casing walls.
The casing flange 23 is suitably mounted upon a discharge plate indicated generally by the reference numeral 24. As shown also in Figure 3, the discharge plate 24 comprises a vertically extending annular outer wall 25 mounted upon and extending upwardly from a generally circular base plate 26 and mounting at the top edge of the wall 25 the casing flange 23. It will be noted that the wall 25 is positioned outwardly (from the pump axis) from the base of the slant walls of the casing 22, although only a short distance outwardly therefrom, for reasons which will be explained hereinafter. A second inner vertically extending annular wall 27 is also mounted on the base 26 concentric with the outer wall 25 but extending slightly below the height of the outer wall 25. The inner wall 27, outer wall 25, casing flange 23 and base plate 26 thus define an annular chamber A, which constitutes an outer peripheral outlet for the pump casing structure, aligned with the radially outermost casing walls at the outlet end, as will be explained hereinafter.
The pump rotor 28 is a generally frusto-conical upwardly apexed body, having the smaller end 28a thereof in substantial registry with the axial pump inlet 21, with a sleeve portion 28b slidably engaging the shaft 11 and locked thereon for rotation therewith by the shaft nut 11a, and having slant walls which diverge in spaced sub stantial alignment with the casing walls 22 substantially the full length of the casing walls 22. The rotor slant walls merge at their base into a substantially cylindrical skirt portion 29 which extends downwardly from the frusto-conical base a short distance. As is seen in Figure 4 as well as Figure 1, the slant walls 28 of the rotor have suitably mounted thereon, on the outer surface, a plurality of substantially straight blades 30, which extend in planes aligned with the pump axis from closely adjacent the rotor top or small end 28a to the base of the frusto-conical rotor walls 28 and beyond a sufficient distance to extend slightly into the annular chamber A.
It will thus be seen that the stock passing through the pump entrance 21 contacts the blades 30 on the rotating rotor 28 and is effectively swirled against the casing walls 22 (which are spaced slightly from the outer edges of the blades 30). The net effect of the moving blades 30 on the rotor 28, which may be operated at speeds ranging from 350 to 1150 revolutions per minute, is to centrifugally separate the heavier impurities from the stock and to centrifugally pump the stock downwardly along the diverting casing walls 22 toward the outlet plate 24. As will be appreciated. the heavy impurities will be driven close to the inside of the casing walls 22 and will be moved downwardly along the inside of the casing walls 22 and urged in the direction of the annular chamber A. As hereinbefore mentioned, the outer wall 25 of the chamber A is positioned outwardly from the base of the frusto-conical walls 22, so that the heavy impurities may slide freely below and outwardly beyond the bottom of the walls 22 and into the chamber A.
The base 26 is provided with a plurality of apertures 31 annularly arranged in registry with the chamber A, so as to provide communication between the chamber A and a draw-off chamber or housing arrangement indicated generally by the reference numeral 32. The drawoff housing 32 consists of inner and outer cylindrical concentric walls 33 and 34 aligned with the inner and outer walls 27 and 25, respectively, so as to constitute downward extensions thereof. The inner and outer walls 33 and 34 merge with downwardly apexed substantially conical concentric inner and outer walls 35 and 36, respectively, so that normal stock fiow through the drawoff chamber 32 would proceed from the chamber A" through the apertures 31, between the concentric cylindrical walls 33 and 34 and then between the concentric conical walls 35 and 36 to substantially the conical apex thereof, whereat a downwardly extending draw-off line 37 and valve 38 are suitably mounted to control stock flow through the draw-off chamber 32.
. It will thus be seen that the valve 38, in effect, may selectively block or open the discharge or outlet chamber A, or in other words, the valve 38 may selectively open or close the draw-off chamber 32 to selectively permit and prevent flow of fluid therethrough. A plurality of stationary vanes 39 aresuitably mounted in the drawoif chamber 32 between the concentric conical walls35 and 36, so as to effectively support the two walls 35 and 36 and also for the purpose of preventing swirling or centrifugal motion of fluid in the pump in this portion of the draw-off chamber 32. It will be noted that the vanes 39 do not extend up to the base plate 36 and, instead, terminate an appreciable distance below the plate 26 so as to provide a region of substantial size wherein swirling of the fluid is reduced from maximum speed to minimum speed upon coming into contact with the vanes 39. As will be appreciated, the heavy impurities passing into the chamber A must be thrown outwardly by centrifugal force and held against the outside wall 25, and the downward extension thereof 34, until the impurities have traveled a substantial distance below the height of the inner discharge plate wall 27, so that eddy currents or the like may not effectively move such impurities back, upwardly and over the wall 27. By thus diverting the divergent generally annular stream of impurityrich fluid or stock outwardly and downwardly through the chamber A and into the draw-off chamber 32 and against a substantially static fluid body maintained therein, because of the vanes 39, it is possible to effectively force the impurities into position so that they may flow freely by gravity forces downwardly through the drawoif chamber 32, ultimately reaching the draw-01f line 37 and valve 3%. Whenever it is desired to remove the impurities accumulated at the bottom of the draw-off chamber 32, the valve 38 is opened and the pump discharges fluid through the outlet chamber A, the draw-off chamber 32 and the draw-off line 37, so as to rinse or flush the impurities out of the draw-off chamber 32. The frequency with which the valve 38 must be opened to clear the chamber 32 of impurities depends upon the rate at which impurities are being removed from the fluid in the pump 16.
The inner discharge plate wall 27, which is positioned substantially at the frusto-conical base of the rotor 28 constitutes an annular partition wall which separates an outer annular peripheral outlet chamber A from a separate uniplanar concentric inner peripheral outer chamber B. It will be appreciated that swirling or centrifugal motion of the fluid during pump operation takes place in chamber A and in chamber B, but the impurity-rich fluid is urged outwardly in chamber A, whereas the impurity-free fluid is urged inwardly and into chamber B, the partition wall 27 being positioned at approximately the division line, or inwardly therefrom, between an outer impurity-rich fluid column and a concentric inner impurity-free fluid column. The discharge plate 24 is provided with a plurality of stationary vanes 40 which are mounted on the base plate 26 and are covered by a substantially circular plate 31 (Figure 1) Whose periphery is substantially aligned with the outermost extremities of the vanes 40 and is very closely spaced from the inner side of the rotor skirt 29, so as to afford close running tolerance. It will be appreicated that leakage between the plate 41 and the skirt 29 is reduced to a minimum because the centrifugal forces generated by the rotor motion would tend to drive fluid downwardly from between the plate 41 and the skirt 29. Each of the vanes 40 is arcuately curved or contoured so as to divert the stock flowing in the chamber B inwardly, toward the pump axis, toward an axially aligned discharge pipe 42 which communicates with the discharge chamber B via an aperture in the central region of the discharge plate base 26 and which extends downwardly therefrom and outwardly through the concentric conical walls 35 V 6 ,and 36, between the vanes 39 in the draw-off chamber 32, as is shown in Figures 1 and 2.
It will also be appreciated that the'general contour of the stationary vanes 40 is such that the stock flow is diverted from the generally circular flow path taken in the annular chamber B along an inwardly curved path, so asto cause a'minimum loss of flow rate as the stock moves inwardly toward the discharge line 42, so that the forces generated in centrifugally pumping the fluid, and separating the impurities therefrom, are available to pump the fluid through the discharge line 42, with a minimum amount of dissipation of such forces during the diverting of the stock flow from the annular chamber B along the vanes 40 and into the discharge line 42.
The instant invention provides a simplified method for pumping stock, in a submerged pump arrangement, wherein no contact with air is involved. Also, the instant apparatus provides for the simultaneous accomplishment of centrifugal pumping and centrifugal separation, so that separation may be eifectively carried out at the maximum swirling speed of the stock generated during the centrifugal pumping operation, and not at a substantially lower speed resulting from frictional losses and the like which may take place in piping stock from a given pump discharge and through the necessary coils to impart centrifugal motion thereto. In addition, the instant invention provides for a stationary vane-equipped draw-off chamber 32 which presents a suitably positioned substantially static body of stock adapted to receive by gravity flow those impurities which have been forced by the centrifugal action of the pump to a suitably positioned outer outlet or discharge chamber. The instant draw-off chamber arrangement thereby permits accumulation of impurities, without the necessity of causing wasteful stock flow through the draw-off chamber 32 at all times during operation of the pump. In addition, the uniplanar concentric inner and outer annular or peripheral discharge outlet arrangement for the instant pump pemits the safe, easy and convenient withdrawal of impurity-free stock from the inside of the stock column or divergent stream that is built up in the pump by the action of the rotating rotor 28. The inner outlet 'or discharge chamber, being equipped with arcuate vanes 40 effectively brings about the discharge of stock that is substantially impurity-free stock and that has substantially all of the energy therein generated by the centrifugal action of the pump, avail-able for pumping stock through the fluid discharge line 42.
Referring now to the embodiment of my invention shown in Figures 5, 6 and 7, wherein those structural elements having substantially the same functions as corresponding elements in the arrangement of Figures 1-4, inclusive, have been designated by the prime of the corresponding reference numeral, the reference numeral 10' designates generally the separator pump. The pump shaft 11 is mounted for rotation on bearings 12', preferably in a closed bearing assembly extending upwardly into a top bearing housing 13, as shown.
The incoming stock flows'into the inlet line 14', and then into a generally annular inlet chamber 50, having the bearing assembly housing 13 mounted on the top thereof and being defined by cylindrical walls 51 mounted on a bottom plate 19' which provides a pump entrance or eye 21, defined by an aperture in the bottom plate 19' which surrounds the shaft 11'.
An upwardly apexed generally frusto-conioal casing member 22 supports from beneath the apertured plate 19' and extends divergingly downward from approximately the outer edges of the pump entrance 21', with which the small end of the casing member 22 is in registry, to a lower or base annular flange 23', which in turn is supported from beneath by a top annular flange 52 for the draw-off chamber 32, all of the elements of which are substantially identical to those shown in Figures 1-4, inclusive.
The pump rotor 53 is a generally frusto-conical upwardly apexed shell, having the smaller end 53a thereof in substantial registry with the axial pump inlet 21' and extending partially therethrough into the inlet chamber 50. A sleeve portion 53b of the rotor 53 slidably engages the shaft 11' and is locked thereon for rotation therewith by the shaft nut 11'a. The rotor 53 has slant walls which diverge in spaced substantial alignment with the casing walls 22', for substantially the full length of the casing walls 22, terminating short of the flange 23. A base piece 530 is preferably separably mounted on the bottom of the rotor 53, so as to define a closed conical rotor shell.
The rotor slant walls 53 have suitably mounted thereon the outer surface, a plurality of substantially straight blades 54, which extend in planes aligned with the pump axis from the rotor top 53a, within the chamber 50, to the base of the frusto-conioal rotor walls 53 and beyond a substantial distance.
It will thus be seen that the stock entering the inlet chamber 50 through the tangential opening 55 for the inlet pipe 14' in the walls 50 is caused initially to swirl in the inlet chamber 50, the rotation of the blades 54, in the direction of swirl, causes acceleration of the swirling effect as the stock is centrifugally pumped downwardly between the casing 22' and the motor 53. The advantageous feature being the initial swirling effect obtained at the inlet chamber 50, so as to assist the blades 54 in their function.
In this embodiment no structure such as the inner or separating wall 27 of Figure 1 is employed, although the cooperation between the inner wall 33 of the draw-off chamber 32' of Figure and the blades 54 may be likened to the cooperation between the inner wall 27 of Figure 1 and the blades 30. In each case the blades 30 or 54 extend outwardly and downwardly from the tops of the walls 27 or 33, respectively, and the blades 30 or 54 constitute moving members which separate two concentrio uniplanar regions or discharge chambers: A and C in Figure 1 and A and C in Figure 5. In each case, the blades 30 or 54 extend downwardly below the lowermost take-01f point for the inner region C or C, as defined by the top of the inner wall 27 in Figure 1, or the top of the inner wall 33' in Figure 4 which is actually capped by the base plate 56.
In Figures 5 and 7, it will be seen that the base plate 56 and the draw-off chamber top flange 52 cooperate to function somewhat as the base plate 26 of Figure 1. The base plate 56 and the flange 52, however, are not connected by uniplanar ribs or webbing since the blades 54 must move in the annular region therebetween; the stationary vanes 39 thus serve additionally as supports to maintain the relative positions of the base plate 56 and the flange 52, although other supports may also be used.
The base plate 56 is centrally apertured to provide communication with the impurity-free stock discharge line 42, and the base plate 56 has suitably arcuately contoured stationary blades 40' capped by the circular plate 41 mounted on the plate 56 and extending from the outer peripheral edge thereof inwardly to function as the blades 40 of Figure 1.
Although I have shown the use of this specific embodiment of my invention in connection with the separation of impurities in paper stock, that are heavier than the paper stock, it will be appreciated that the instant apparatus may well be used in the separation of any of a number of impurities which may be present in a fluid that is lighter than the impurities. For example, the instant apparatus might be used in the separation of liquid impurities from a gaseous fluid, as well as solid impurities from a liquid fluid.
It will, of course, be understood that various details of construction and operation may be varied through a wide range without departing from the principles of this invention and it is, therefore, not the purpose to limit the patent granted hereon otherwise than necessitated by the scope of the appended claims.
I claim as my invention:
1. A fluid pump and centrifuge for separating heavier impurities from a fluid and simultaneously pumping said fluid, comprising a stationary frustoconical casing having a substantially vertical axis and having an inlet at the smaller upper end thereof and two annular outlets at the other, lower end thereof, a substantially vertical shaft extending into said casing, a frusto-conical rotor having the smaller end thereof registering with the inlet end of the casing and mounted on said shaft in said casing, said casing and rotor coacting to define an annular frustoconical pumping chamber therebetween, blades mounted on said rotor and extending into said pumping chamber to move the fluid therein to centrifugally force the heavier impurities in the fluid toward the radially outermost casing wall and to centrifugally pump the fluid from the inlet toward the outlets, one of said outlets being substantially axially aligned with the radially outermost casing wall at the outlet end to receive fluid containing the centrifugally outwardly forced impurities, the other outlet being positioned radially inwardly of said one outlet to receive the lighter impurity free fluid from the pumping chamber, a draw-off chamber below and in communication with said one outlet and inclined downwardly below the said one outlet to accommodate gravity flow of the impurities thereinto and gravitational settling of the impurities therein to a point at the bottom thereof, means in said drawoff chamber for retarding fluid movement therein to provide a substantially static fluid in the draw-off chamber, means providing a fluid connection between said outlets at a point in the radially inward face of said one inlet to permit fluid to pass from said draw-off chamber to the other outlet after the impurities have been removed by gravitation to the bottom of said draw-off chamber, and means for selectively opening and closing said draw-off chamber at the bottom thereof to selectively permit and prevent flow of fluid therethrough to rinse out accumulated impurities therein.
2. The structure recited in claim 1 wherein said outlets are separated by a substantially vertically upstanding annular wall radially inwardly of said one outlet over which fluid must rise to move from said one outlet to the other outlet thereby requiring the fluid to follow a tortuous upward path from the draw-off chamber to the said other outlet to thereby assure that the heavy impurities will be gravitationally separated from said fluid in said draw-off chamber.
3. The structure recited in claim 1 wherein said means in said draw-off chamber for retarding the fluid comprises at least one vane fixedly secured to said stationary casing and intercepting the flow of fluid from said one outlet.
References Cited in the file of this patent UNITED STATES PATENTS 1,301,544 Crombie Apr. 22, 1919 2,255,807 Plumlee Sept. 16, 1941 FOREIGN PATENTS 14,024 Great Britain of 1909 401,693 France of 1909 142,807 Austria of 1935