US 3539279 A
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Description (OCR text may contain errors)
Nov, 10, 1970 A. L. RIDER ETAL TUBULAR PUMP Filed Sept. 23, 1968 United States Patent US. Cl. 418-48 7 Claims ABSTRACT OF THE DISCLOSURE The disclosure pertains to a tubular pump of the progressive cavity type including a rotor, a drive shaft confined within a casing defining an interior passage into which a fluid is delivered for movement out of the discharge end of the pump, and a universal joint coupling between said drive shaft and said rotor consisting of a pair of universal joints arranged back to back, a first drive pin connectingan outer end of one of said joints to said drive shaft, a second drive pin connecting the outer end of the other of said pair of joints to said rotor, together with a fluid filled boot secured in enveloping relation to said coupling for preventing collapse of the boot and protecting said universal joints from damage by the pumped fluid.
As is perhaps well known, a progressive cavity pump comprises a single thread rotor inside a double thread unit or stator which carries the fluid to be pumped with positive pressure and continuous flow. In such pumps, the axis of the rotor follows a circular path and in the opposite direction from the movement of the rotor and, of course, the diameter of such circular path will vary with the size of the rotor. Means for driving the rotor can take the form of either a flexible cable, or a double universal joint between a drive shaft and rotor, or a single universal joint between a drive shaft and the rotor, and a flexible stator, or a pin connected rod pinned at one end to the drive shaft and the rotor at its other end. The present invention is directed to the last mentioned type of drive means, of which the prior designs have been unsatisfactory because of the frequent requirement of replacing the drive pins, drive shaft, connecting rod and rotor, whereas a preferred embodiment of our invention is capable of operation for approximately 800 days without replacement of pins or other parts.
A primary object of our present invention is to provide a tubular pump of increased reliability and with a reduction in maintenance expense from a standpoint of time and money.
Another important object of the invention is to provide a tubular pump of the indicated nature which is additionally characterized by the elimination of the necessity of having stainless to stainless moving parts and permitting the use of less expensive and better metals.
A still further object of our invention is to provide a tubular pump of the aforementioned character which includes a member permitting the pumping of food products or fluids of foods that would otherwise subject the pump parts to corrosion and abrasion.
Another object of the invention is to provide a tubular pump of the indicated nature which enables the replacement of the entire universal joint coupling as a unit, or removal and replacement of but one or more components thereof separately.
Other objects of the invention, together with some of the advantageous features thereof, will appear from the following description of a preferred embodiment of the invention which is illustrated in the accompanying drawings. It is to be understood, however, that I am not to be limited to the precise embodiment shown, nor to the precise arrangement of the component parts thereof, as
my invention, as defined in the appended claims, can be embodied in a plurality and variety of forms.
Referring to the drawings:
FIG. 1 is a side elevational view, partly in section, and partly broken away, of a preferred embodiment of our invention.
FIG. 2 is a broken top plan view, partly in section of a preferred embodiment of the invention, partly broken away to illustrate the construction.
FIG. 3 is a perspective view, partly broken away to illustrate components of the universal joint coupling of a preferred embodiment of the invention.
In its preferred form, the tubular pump of our present invention, as adapted to be driven by a uni-directional motor or a reversing motor rotating a motor shaft, preferably comprises, in combination with a source of fluid, a casing defining an interior passage for said fluid, a rotor, a stator encompassing said rotor and supported by said casing; said stator defining in association with said rotor a series of progressive cavities therebetween which are in communication with one another with said passage as well as with a discharge outlet of said casing, together with a universal joint coupling connecting said drive shaft and said rotor and consisting of a pair of universal joints, (preferably of the so-called Hookes type), an intermediate shaft between said pair of universal joints; one of said pair of joints being mounted at its outer end on said drive shaft and pin-connected thereto, and the other of said pair of joints being pin-connected at its outer end to said stub shaft and said rotor, and an endless protector boot enveloping said coupling and containing a filler material.
As particularly illustrated in FIG. 3 of the annexed drawings, we provide an elongated tubular casing 11 affording a pump body which can be cast from iron but preferably is cast from stainless steel in order that the pump can elfectively handle fluids that might be damaging to iron such as corrode the metal or subject it to abrasion. The casing 11 defines an interior passage 12 for the reception of material through an inlet 13 and for flow of such material to the discharge end 14 of the pump. As shown in FIG. 1, the pump is placed in driving connection with driving means such as the shaft 15 of a motor, not shown, provided with a coupling 20, by means of a drive shaft 16 having a key-way 17 therein cooperating through a key 17' on shaft 15. The drive shaft 16 is mounted for rotation on the longitudinal axis of the pump by conventional sealed front and rear bearings 18 and 19, respectively, which are supported and held against lateral displacement within the casing 11 by means of interior shoulders 21 and 22 respectively, formed on the inner wall of the casing. Preferably, the bearings 18 and 19 are tapered roller bearings which are adjusted for end play by adjustment nuts 23 and 24. An oil seal 26 at the forward end of the pump body 11 is provided to prevent the escape of lubricant in the usual manner with a similar shaft seal 26 in a plate at the other end of the bearing housing 31, and a standard shaft seal 27 sealing against a plate 28 likewise is provided as customary. Of course, a stufling box type of packing can be used instead of shaft seal 27. Through-bolts 29 and 30 serves to hold these various components together and to an outer flange 31 of the pump body. As illustrated, suitable pump supports 32 and 3-3 for carrying the casing in an elevated position in relation to the ground or other surface may be provided adjacent to opposite ends of the casing ill, such supports including uprights 34- and 3 5 bolted by means of bolts not shown to flanges on the pump body.
In accordance with our present invention, we provide in combination with a standard assembly of rotor 38 and stator 39 supported in the conventional manner with the pump casing 11, a specially constructed universal joint coupling which is designed generally by the reference numeral 41 in the accompanying drawings. As shown particularly in FIG. 2, our improved universal joint coupling is wholly confined and housed within a protective envelope 42 which preferably is in the form of a boot or sleeve and preferably fabricated of Neoprene which is chemically inert to an appreciable number or extent to all fluids that might be pumped through the pump body. The interior of the Neoprene boot or sleeve 42 is filled with grease or with a tasteless, odorless, relatively non-toxic, noncompressible, non-corrosive, semi-fluid, such as a silicone compound in order to keep the sleeve from collapsing under external pressure during operation or otherwise. The universal joint coupling 41 is connected at one end to the drive shaft 16 by means of a drive pin 43 in order to transmit both axial load and torque, and is similarly connected by means of a drive pin 44 to the rotor 38, see especially FIGS. 1 and 2 of the annexed drawings.
In order to reduce manufacturing costs to a minimum and yet afford a universal joint and connections to the drive shaft and to the pump rotor which will be highly effective in that motion between the drive pins and connecting stubshaft is eliminated thereby reducing wear on such pins to an absolute minimum, we provide in our improved universal joint coupling 41 which comprises two so-called Hookes type universal joints consisting of a pair of needle bearings 46 and 47, a pair of yoke-carried crosses 51 and 52, together with yokes 56 and 57 which support needle bearings 46 and 47 and partially carry the crosses 51 and 52, respectively, additional yokes 58 and 59 for supporting the crosses 51 and 52; said yokes extending laterally in opposite directions from yoke heads 60, see FIG. 2, as well as additional yokes 61 and 61 for supporting needle bearings 63 and 63', respectively; the latter yokes extending laterally in opposite directions from yoke heads 60 and 62. The coupling 41 also includes an intermediate shaft or spacer 64 which can be a separate unit welded to yoke heads 60 or can be formed integral with the coupling, as shown. Such intermediate shaft or spacer 64 can be lengthened as desired to reduce the angular motion of the coupling 41 for larger sizes of pumps. As shown in FIG. 2, drive shaft 16 extends into a flanged hub 66 of coupling 41 and is pin-connected thereto by drive pin 43. At the opposite end of the coupling we provide a stub shaft 48 which is telescopically fitted within the inner end of rotor 38 and which is preferably formed integral with the adjacent flanged end 67 of the coupling 41; such stub shaft 48 being pin-connected to rotor 38 by drive pin 44.
As illustrated particularly in FIG. 2, the opposed end flanged hub 66 and flanged end 67 which are pin-connected to drive shaft 16 and to stub shaft 48, respectively, and are so fabricated as to provide on each end thereof a flat periphery 68 and 69, respectively, which receive the deformed extremities 71 and 72 of the Neoprene boot or sleeve 42. We detachably secure the boot in place by means of steel annular bands 73 and 74 which are slipped over the deformed extremities of the boot firmly to hold the boot upon such flanges 66 and 67.
The mountings of the rotor and stator 38 and 39 can be as desired. As usual, a compression fit is provided between the metal rotor and the rubber stator in order to reduce slippage, with through-bolts 78 and 79 extending between end plates 81 and 82, and with the ends of stator 39 bearings against said end plates which hold suitable O-rings to retain the stator in operative position and sealed. The rotor 38 can be fabricated of either tool steel or stainless steel and is covered with a heavy layer of chrome to resist abrasion. If the material to be pumped is a food substance, such as citrus fruit juices or the like, stainless steel should be used for the rotor. The stator is conveniently formed from natural or a synthetic rubber, or other suitable material, and as shown in FIG. 1 forms with the rotor 38 a series of cavities which are progressive from one end of the stator communicating with interior passage 12 to its opposite end at the discharge end 14 of the casing, and thus carry the fluid in the pumping action from the inlet to the outlet as the rotor 38 turns within the stator 39. Since sealing -O-rings are provided and are located at the joints of the rubber stator and metal shell. carbon steel instead of stainless steel can be used, and threading of the stator shell also is thus eliminated. It is also to be observed that the parts of our improved pump which are in contact with the fluid being pumped are fabricated of Neoprene and stainless steel and, accordingly, food products can readily be pumped in our improvement which products would corrode pump bodies and parts made of carbon steel.
It is also to be noted that the complete flexible universal joint coupling 41 can be replaced as a unit, or the coupling can be reconditioned by replacing the neoprene sleeve 42 separately as well as replacing wearing parts as required.
1. A tubular pump comprising, in combination with a motor shaft and a source of fluid to be pumped, a casing defining an interior passage into which said fluid is fed, a rotor in said casing, a stator surrounding said rotor and defining therewith progressive cavities communicating with said interior passage and with the discharge end of said casing, a drive shaft, a stub shaft, a universal joint coupling between said drive shaft and said rotor; said universal joint coupling comprising two Hookes type universal joints with the outer end of one of said two universal joints mounted on said drive shaft and pin-connected thereto, and with the outer stub shaft end of the other of said two universal joints pin-connected to said rotor, and a fluid-filled protective boot enveloping said universal joint coupling.
2. A tubular pump as defined in claim 1 wherein said protective boot consists of a Neoprene sleeve and the fluid filling the same is non-compressible in order to maintain the size and shape of said boot and to prevent collapse thereof.
3. A tubular pump as defined in claim 1 wherein said two universal joints are arranged to face in opposite directions, and a spacer interposed between and two universal joints.
4. In a tubular pump of the progressive cavity type including a stator and a rotor, means for driving said rotor comprising, in combination with a motor shaft, a drive shaft connected to said motor shaft, a stub-shaft, a universal joint coupling; said universal joint coupling comprising a pair of Hookes type universal joints, a first drive pin connecting the outer end of one of said pair of universal joints to said drive shaft, a second drive pin connecting the outer stub shaft end of the other of said pair of universal joints to said rotor, and a Neoprene fluid-filled sleeve enveloping said universal joint coupling.
5. In a tubular pump as defined in claim 4 wherein said universal joint coupling comprises a hub at one extremity thereof, a flanged end at the other extremity thereof, a first pair of flange yokes welded to said hub and to said flanged end and arranged in opposed longitudinal relationship to one another, a second pair of flange yokes welded to said hub and said flanged end of said coupling arranged in opposed transverse relationship to one another at approximately ninety degrees in respect to said first pair of flange yokes; each of said yokes having an opening therein, bearings supported by the openings in said flange yokes, cross-members oscillatably supported in said bearings and a stub-shaft welded to said flanged end of said coupling.
6. In a tubular pump as defined in claim 5, and a protective fluid-filled sleeve clamped to and enveloping said universal joint coupling.
7. A tubular pump as defined in claim 6, and a chemically-inert, non-compressible, tasteless, odorless semi- 6 fluid in said sleeve for maintaining the shape and size 3,324,801 6/1967 Fernholtz. thereof and for keeping said sleeve from collapsing. 3,340,814 9/ 1967 Streicher.
References Cited FOREIGN PATENTS UNITED STATES PATENTS 5 602,794 3/1960 Italy. 2,695,694 11/1954 Seinfeld. 2,915,979 12/1959 Bourke et a1. MARK NEWMAN Pnmary Examme 2,924,180 2/1960 Bourke et a1. W. J. GOODLIN, Assistant Examiner 3,097,609 7/1963 Nechine.