US3857654A - Adjustable diameter stator for excentric helical screw pump - Google Patents

Adjustable diameter stator for excentric helical screw pump Download PDF

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Publication number
US3857654A
US3857654A US00325748A US32574873A US3857654A US 3857654 A US3857654 A US 3857654A US 00325748 A US00325748 A US 00325748A US 32574873 A US32574873 A US 32574873A US 3857654 A US3857654 A US 3857654A
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Prior art keywords
slats
stator
slat
segmental
sleeve
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US00325748A
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English (en)
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M Streicher
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Foerdertechnik Streicher GmbH
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Foerdertechnik Streicher GmbH
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Priority claimed from DE19722202763 external-priority patent/DE2202763C3/de
Priority claimed from DE19722243479 external-priority patent/DE2243479B2/de
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C2/00—Rotary-piston machines or pumps
    • F04C2/08—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing
    • F04C2/10—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of internal-axis type with the outer member having more teeth or tooth-equivalents, e.g. rollers, than the inner member
    • F04C2/107—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of internal-axis type with the outer member having more teeth or tooth-equivalents, e.g. rollers, than the inner member with helical teeth
    • F04C2/1071—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of internal-axis type with the outer member having more teeth or tooth-equivalents, e.g. rollers, than the inner member with helical teeth the inner and outer member having a different number of threads and one of the two being made of elastic materials, e.g. Moineau type
    • F04C2/1073—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of internal-axis type with the outer member having more teeth or tooth-equivalents, e.g. rollers, than the inner member with helical teeth the inner and outer member having a different number of threads and one of the two being made of elastic materials, e.g. Moineau type where one member is stationary while the other member rotates and orbits
    • F04C2/1075—Construction of the stationary member

Definitions

  • the radial compression which is obtained by one of various me chanical adjusting means, is transmitted to the segmental slats through anti-friction type roll bodies which press against the slats, the compression forces being distributed over the roll bodies through a compression transmitting means such as a casing, sleeves,
  • the present invention relates to eccentric helical screw pumps, and in particular to helical screw pumps having a resiliently compressible stator sleeve of adjustable diameter and means for effecting such a radial compression of the stator sleeve.
  • the diameter adjustment can be obtained by means of adjustment screws which advance radially against the half-shells, or segmental slats, respectively.
  • Anotherprior art device suggests compression adjustment by means of two axially opposing tapered sleeves which engage a plurality ofradially movable pressure pins, which in turn bear against the segmental slats on the stator sleeve. Only two or four segmental slats are normally employed in this type of device.
  • Another prior art device has a one-piece jacket surrounding its stator sleeve, the jacket being rendered radially yielding through the arrangement of eight slits in the midportion of its length.
  • the present invention is aimed at improvements in the construction of adjustable diameter stators for helical screw pumps in which the diameter adjustment is obtained by means of simple mechanical adjusting means, the stator sleeve being adjusted through the application of a very uniform radial compression over the entire circumference and length of the stator sleeve, thereby providing improved longevity of the latter, as well as an improvement in operational efficiency and reliability.
  • stator assembly comprising a stator sleeve defining a twin helix cavity which cooperates with the pump screw, the stator sleeve being molded of rubber or a similar material.
  • the stator sleeve is surrounded by a jacket which consists of a comparatively large number of segmental slats of hard, highly resistant material. These slats are arranged in parallel and extend longitudinally over at leasta major portion of the stator sleeve.
  • the assembly further includes means for adjusting and for transmitting radial compression forces to the segmental slats, in order to reduce the diameter of the stator sleeve, said means including a plurality of roll bodies of hard, non-compressible material which are 'arranged in at least two spaced radial planes, the compression transmitting means supporting these roll bodies against the outside.
  • An increase in compression causes the roll bodies to be forced radially inwardly against the segmental slats so that the diameter of the stator sleeve is reduced accordingly in a very uniform manner. No leak problemshave been encountered with this kind of solution.
  • segmental slats must therefore be of hard, highly resistant material and they should have as small a circumference pitch as possible, i.e., they should be'numerous.
  • the invention permits an adjustment of the radial compression by means of only a single mechanical adjusting element, similar to the case of a hydraulic pressure transmission.
  • the material of the stator sleeve can now be worn much further, as the diameter of the stator sleeve is progressively reduced, thereby extending the operational life of the pump.
  • the uniformity of concentric adjustment provides a true-to-shape reduction in all cross sections of the twin helix.
  • the wear and abrasion is similarly uniform along the entire length so that the suction power and pumping capacity are not markedly reduced after a certain amount of wear.
  • stator sleeve when the stator sleeve is finally worn out, it is not necessary to replace the entire stator assembly, the stator sleeve alone being interchangeable, as suggested by the present invention. In some cases, however, some of the segmental slats are permanently attached to the stator sleeve and they, too, will have to be replaced. The roll body system and the remaining parts of the stator assembly, with few exceptions, can normally be reused.
  • segmental slats of the jacket define an overlap in the circumferential direction, forming a jacket which completely envelops the surface of the stator sleeve along its entire length.
  • the roll bodies bear against these overlapping segmental slats in grooves defined by successive overlaps.
  • stator sleeve is radially completely confined. Small differential stresses may be created within the circumferential area of each slat, but, as in the case of a closed sleeve, they are almost completely balanced and can therefore be neglected.
  • stator assembly having a stator sleeve which is completely enclosed by slats exhibits similar characteristics as if surrounded by a closed sleeve, except for the fact that it is now adjustable in diameter and that the cost of the slat envelope is considerably less than that of a closed cylinder sleeve.
  • stator assemblies it is not necessary, furthermore, that the outer surface or the inner surface of these slats be truly cylindrical. It is thus possible to use segmental slats of identical profile, but in various numbers, in order to obtain stator assemblies of different diameters. It is now also possible to design stator assemblies according to the invention which have the same overall dimensions as are found in previously used largely standardized versions, where adjustment was not possible. The adjustable diameter stator assembly can thus be simply substituted for a non-adjustable one.
  • each slat consists of three profile portions, an arcuate inner slat portion, an arcuate outer slat portion, and an offset portion joining the inner and outer slat portions.
  • the outer surface of the inner slat portion and the inner surface of the outer slat portion are preferably so arranged that they are part of a common hypothetical cylinder surfae. Assembled, the inner and outer surfacesof these slat portions thus coincide at least approximately with three concentric, equidistance cylinder surfaces.
  • the offset portion of the slat profile has the additional advantage of reinforcing the slat, thereby improving the longitudinal transmission of compression forces which are applied to the slat at several spaced points only. It is thus possible to obtain a jacket of segmental slats which has a substantially cylindrical outer contour and where the approach motion between the slats during diameter adjustment takes place along concentric contact faces which lie on a common cylinder.
  • stator assembly with two end rings which are firmly and tightly attached at the two ends of the stator sleeve, the segmental slats being shortened accordingly so as to be longitudinally confined between the end rings.
  • the latter may further include an axially extending centering collar. This arrangement eliminates any sealing problems, and the segmental slats are conveniently retained on the stator sleeve periphery without the need for additional retaining means.
  • FIG. I is a longitudinal cross section, partially cut away, of a stator assembly for an eccentric helical screw pump embodying the invention
  • FIG. 2 is a transverse cross section through the stator assembly of FIG. 1, taken along line Il-Il thereof;
  • FIG. 3 is a longitudinal cross section through a part of a stator assembly representing a second embodiment of the invention
  • FIG. 4 is a transverse cross section through the stator assembly of FIG. 3, taken along line IV-IV thereof;
  • FIG. 5 shows another embodiment using a roller chain
  • FIG. 6 shows an enlarged plan view detail of the chain of FIG. 5;
  • FIG. 7 shows in a partial longitudinal cross section still another embodiment of the invention.
  • FIG. 8 is a partial transverse cross section of still another embodiment of the invention.
  • FIG. 9 is a longitudinal cross section through the assembly of FIG. 8, taken along line IX-IX thereof;
  • FIG. 10 is a longitudinal cross section through a further embodiment of the invention.
  • FIG. 11 is a transverse cross section through a further embodiment of the invention.
  • FIG. 12 shows an enlarged cross sectional detail of FIG. 11 in the area XII.
  • FIGS. 1 and 2 is shown a stator sleeve 1, the cen-, tral cavity of which defines the twin helix 2 of an eccentric helical screw pump.
  • a sleeve jacket which is composed of alternating segmental slats 4 and 5.
  • the dove-tailing edges of these segmental slats are inclined in relation to the radial direction by approximately 30 to 50 of angle.
  • the segmental slats are directly adjoining one another at their longitudinal edges 6 along which they execute relative radial motions during diameter adjustment.
  • the stator sleeve 1 itself is molded of abrasion resistant rubber or of a similar, highly resilient synthetic material.
  • the segmental slats in contrast, are of a very hard, highly resistant material, preferably hardened steel, and have ground longitudinal edge surfaces 6.
  • every second slat e.g., every slat 5 is permanently attached to the stator sleeve by a vulcanized bond between the slat base 7 and the outer surface of the stator sleeve 1.
  • the slats 4 are then loosely positioned between the attached slats 5.
  • Such a bond is preferably restricted to the central portion of the surface 7, the strength of the bond being just high enough to prevent detachment of the slats 5 from the stator sleeve circumference.
  • stator sleeve the slats 4, rather than the slats 5.
  • the former then define dovetailshaped grooves into which the loose slats 5 can be inserted longitudinally, the resulting assembly forming a coherent unit between the stator sleeve 1 and the jacket 3. ln order to facilitate this insertion assembly, it'may be necessary to provide a certain lateral clearance between the attached slats 4.
  • the stator assembly further includes a casing 8 which is arranged concentrically with the jacket 3, the casing carrying at each longitudinal end a flange l0, centered by a centering shoulder 9.
  • the flanges 10 also serve to axially position the stator sleeve 1. Clamping rods extending between the two axial end flanges 10 provide a clamping action on the assembly in the conventional manner.
  • annular space 11 which space is completely filled with balls 12.
  • a set screw 13 including screw retaining means, ifdesired, the penetration depth of screw 13 determining thedegree of compression exerted on the balls within the annular space 11. Since the total volume occupied by these balls is essentially fixed and cannot thereforebe reduced by the penetration of screw 13 into space 11, the .balls react in a manner comparable to that of a non-compressible liquid.
  • the halls being of hardened ground steel, are
  • the set screw 13 illustrated in FIG.'1 may be replaced by a piston, and the latter may be spring biased to provide the compression force.
  • the spring preload is made adjustable by means of a set screw.
  • a spring element is not really necessary,since the stator sleeve 1 itself is a resilient element producing a deformation bias against the compression forces.
  • the set screw 13 may have any desired length. It is also possible to provide a number of such screws, the adjustment effect of each screw being distributed largely over the entire annular space 11.
  • the maximum penetration volume of all set screws 13 should correspond to the maximum abrasion volume permitted on the pump helix 2.
  • FIGS. 3 and 4 illustrating a different embodiment of the invention, feature a groove profile 14 of which at least two are arranged at an axial spacing on the jacket 3.
  • the groove profile is composed of an annular angle profile 15 and a planar cover profile 16 attached thereto by means of screws.
  • Inside the annular space 11 of each groove profile is provided an even number of alternating rollers 17 and 18, the rollers l7-being biased radially inwardly, while the rollers 18 are biased radially outwardly.
  • the rollers arepositioned by means of a cage 19 which allows for sufficient displacement of the rollers during adjustment motion. Adjustment is provided by means of a radially oriented set screw 13' which engages a threaded bushing 21 in the axial leg 20 of thegroove profile 14.
  • This set screw bears against one ofthe outwardly biased rollers 18.
  • the screw can be advanced radially inwardly until this roller 18 is lowered to the circle occupied by the roller 17.
  • the other rollers are thereby forced to execute a circumferential motion away from the advancing roller 18.
  • the annular distance between contacting rollers 17 and 18 can only be reduced by a radially inwardly directed adjustment motion of the inner rollers 17,
  • each set screw 13' may be adjustable separately to increase the radial compression on all the rollers.
  • the essential element is a rigid ring as defined by the axial leg 20 of the angle profile, combined with a means to prevent the axial escapement of the roll bodies.
  • the proposed cage 19 may be of sheet metal, or it may be molded of hard plastic. Alternatively, the cage may be provided with a limited degree of flexibility so as to serve as a cage band.
  • FIGS. 5 and 6 A further embodiment of the-invention is shown in FIGS. 5 and 6. They illustrate a roller chain 22 consisting of chain links 23, pins 24, rollers 25, and a chain lock 26.
  • the chain lock 26 draws the two chain ends toward one another and thereby closes the chain around the circumference of the jacket 3, producing the desired radial compression.
  • the pins 24 extending through the rollers 25, the latter may be provided with axial trunnions engaging the chain links. No supporting envelope or sleeve is required in this embodiment, since the compression forces are transmitted through the links 23 of the roller chain.
  • the chain lock 26, as illustrated may also be used any other known chain tensioning device;
  • FIG; 7 illustrates the use of several spaced'annular rows of balls 27 arranged at an axialdistance from one another on the circumference of jacket 3.
  • These rows of balls may be provided with or without a ball cage, the balls being axially positioned by ring members 28 and 29 and radially retained by inwardly tapered end faces 29a provided on the larger ring members 29.
  • These ring members are arranged to be forcibly clamped together in the axial direction, using known devices such as end flanges andthreaded rods extending therebetween, for example. This clamping action causes the balls 27 to be pushed radially inwardly under the action of the tapered end faces 29a, thereby creating a radial compression on the jacket 3.
  • This arrangement makes it possible to provide any desired number of radial clamping positions in a simple, inexpensive configuration.
  • a still further embodiment using roll bodies for the distribution of compression forces is illustrated in F [68.8 and 9.
  • This embodiment features roll bodies in the form of longitudinally extending rods or steel tubes 31 or by an elongated clamping sleeve.
  • an adjusting means such as a bolt and nut.
  • the tubes or rods do not contact one another in the circumferential direction, a small clearance being required to allow for radial reduction of the stator sleeve diameter, as previously described.
  • the axial length of the'rods 30 need not be identical to the length of the stator sleeve, but it should preferably be more than one-half of the sleeve length.
  • the jacket 3 should be composed of at least 10, preferably however more than 15 segmental slats, in order to assure a uniform adjustment of the sleeve diameter.
  • the slats may be attached to the stator sleeve by other means than a vulcanized bond.
  • these clearances should be kept very small so as not to impede the rolling displacement of the roll bodies on the outer face of the slats.
  • FIGS. 10, 11, and 12 is illustrated a still further embodiment of the invention.
  • the stator assembly includes at each end of the stator sleeve 1 an end ring 33 which may be permanently attached to the cylindrical outersurface 34 of the stator sleeve by a vulcanized bond, for example. Between the end rings 33 extend the segmental slats 35. Centering collars 36 on these end ringsretain the slats against the stator sleeve 1. I
  • each segmental slat 35 has a cross-sectional profile which is composed of an inner arcuate slat portion 37, an outer arcuate slat portion 38, and an offset profile portion 39 between the twoarcuate slat portions.
  • the slat portions 37 and 38 thereby represent each a segment of a cylinder, the difference between the inner radii of curvature r2 and r1 being equal to the wall thickness s of the stock from which the segmental slat is formed.
  • the inner radius r2 of the outer slat portion is equal to and coinciding with the outer radius of the inner slat portion.
  • the offset portion 39 of the slat profile may include a straight inclined por-' tion, the angle of inclination b being comprised between 20 and 45, preferably 30.
  • the outer surface of the stator sleeve has in this case a profile which corresponds exactly to the overlapped inner profile of the segmental slats. No connection is therefore necessary between the individual slats which can be mounted by merely inserting them under the centering collars 36 of the end ring 33, whereby a slight elastic deformation of the stator sleeve may take place.
  • the stator sleeve may be molded into the assembled end rings and segmental slats. In this case the inner sides of the slats may be entirely or partially bonded to the stator sleeve by vulcanization, the latter beingcontrolled or prevented, where desired, by the application of intermediate coatings.
  • the inner side 40 and the end face 41 of the inner slat portion 35 is bonded to the stator sleeve by vulcanization, while the inner side 42 of the offset portion and the inner side 43 of the outer slat portion are not attached to the stator sleeve.
  • an adjustment motion is possible on these surfaces 42 and 43. It is also possible to restrict the vulcanized bond to the end face 41, in which case the entire inner surface of the seg-. mental slats is allowed to shift relative to the outer surface of the stator sleeve 1. This adjustment motion is facilitated by a small angle of inclination b at the offset profile portion 39 of the slats.
  • the overall adjustability of a stator sleeve having an outer diameter of approximately mm, for example, is within the range of 3 to 6 mm of diameter reduction.
  • the adjustment displacement at the overlap would be between 0.8 and 1.6 mm.
  • Such a displacement is therefore easily accommodated, even where all segmental slats are bonded to the stator sleeve by vulcanization.
  • FIGS. 10 to 12 shows the segmental slats arranged so that their adjustment surface of radius r2 is concentric with the stator axis 44.
  • such precision is not required so that, instead of the 13 slats illustrated in FIG. 11, 12, or 14, 15, or even as few as 10 of these slats may be assembled on a different stator sleeve diameter, using aproximately the same overlap distance a.
  • the assembled stator sleeve 1 and segmental slats 35 thus present an overall cylindrical outer surface 45, with longitudinal grooves 46 arranged therein, the grooves being defined by a bottom represented by the outer surface 46 of the inner slat portion 35, by one lateral face represented by the end face 48 of the outer slat portion 38, and by another lateral face represented by the outside of the offset slat portion 39.
  • Within these grooves are arranged, in axial spacing, several circumferential rows of steel balls 49 (see FIG. 10) which are axially positioned and radially retained by closed ring members 52, 54 and 55, arranged concentrically around the stator sleeve.
  • Within the thirteen longitudinal grooves 46 are thus arranged in three circumferential rows 39 such balls.
  • each ball is thereby approximately equal to its diameter; it should be no less than 0.5 times, but preferably between 0.8 and 1.5 times its diameter.
  • Radial compression on the balls 49 is obtained by axially clamping the ring members 52, 54 and 55 against one another, whereby opposing tapered end faces 50 transform the axial compression forces into uniform radial compression forces between the balls 49 and the segmental slats 35. These forces are further distributed within the length of each slat by the longitudinal rigidity of the segmental slats 35 having a stock thickness of approximately mm, with their rigidity being considerably enhanced by the special slat profile with its offset profile portion 39.
  • FIG. 10 shows a clamping mechanism which takes advantage of the normally required housing end flanges 57 and of the clamping rods 58 by means of which the pump housing and stator assembly are clamped together.
  • end flanges 57 in this case abut axially against the end faces 60 of the stator sleeve, the otherwise flat clamping face of the flange 57 including an annular groove 61 with an O-ring 62 received therein, the latter sealing the interface between the outer surface 34 of the stator sleeve and the segmental slats.
  • This arrangement provides a direct seal between the end flanges 57 and the stator sleeve 1.
  • each clamping rod 57 either carries a separate clamping bracket engaging the thrust ring 56, or a closed clamping ring 64 with a bore for each clamping rod is arranged to engage the thrust ring 56 so that the axial clamping adjustment can be set conveniently by means of clamping nuts 65 and counter nuts 66.
  • a major advantage of this embodiment resides in the fact that the overall assembly dimensions of the novel adjustable diameter stator sleeve are such that it can be substituted for previously used non-adjustable stator sleeves.
  • This compactness is primarily due to the use of comparatively small steel balls in conjunction with the clamping mechanism featuring closed ring members 51, 52, etc. It should be understood, of course, that other clamping mechanisms than those illustrated in the drawings may be used together with intermediate roll bodies for the purpose of obtaining a most uniform distribution of the compression forces on the stator sleeve.
  • An adjustable stator assembly for ahelical screw pump comprising in combination:
  • stator sleeve of a resiliently yielding material such as rubber and the like having a longitudinal cavity defined by a twin helix inside which may be received, in a known manner, an eccentrically rotating helical screw;
  • the compressing means including:
  • the roll bodies are balls arranged in several single annular rows around the segmental slats with small clearances between circumferentially adjacen balls;
  • the compression transmitting means is in the form of several axially spaced closed ring members surrounding the stator sleeve, each row of balls being axially abutted and radially restrained by the opposing ends of two such ring members of which at least one has an inwardly tapered end face with which it engages the balls;
  • the compression adjusting means is a means for forcibly approaching said ring members axially against each other, thereby creating an adjustable radially inwardly directed compression against said balls at least every other segmental slat is attached to the stator sleeve by means of a vulcanized bond.
  • segmental slats are arranged adjacent to one another on the circumference of the stator sleeve, the slats being dispaceable relative to each other at least in the circumferential direction.
  • segmental slats are arranged so that they circumferentially adjoin each other;
  • the surfaces of contact between adjoining slats are inclined in relation to the radial direction so that a reduction in the sleeve diameter under radial compression and a corresponding circumferential approach movement of the slats is made possible through a radial escape movement of adjoining slats along said contact surfaces.
  • the nummber of slats is an even one
  • said contact surfaces between adjoining slats are inclined alternatingly in opposite direction in relation to the radial direction;
  • the slats have a generally trapezoidal cross-sectional outline with alternatingly inwardly and outwardly facing bases.
  • the slats which have their trapezoidal base facing radially inwardly are attached to the stator sleeve by means of a vulcanized bond.
  • the compression transmitting means includes a rigid outer casing surrounding the stator sleeve at a radial distance from said slats so as to form a substantially closed annular space around the stator sleeve within which are received the roll bodies;
  • the roll bodies are balls of such size and number that they occupy said annular space in its entirety;
  • the adjusting means includes a member capable of being forcibly advanced into said annular space so as to reduce its volume, the member thereby creating an increasing compression between the balls, which compression is transmitted by said rigid casing to all parts of said stator sleeve.
  • said-member of the adjusting means is a set screw extending through a threaded bore in the wall of said casing.
  • the compression transmitting means includes at least two longitudinally spaced rigid profiles, each surrounding the stator sleeve at a radial distance from said slats so as to form an annular space around the stator sleeve within which are received the roll bodies, said means further including means for axially retaining the roll bodies so that they remain within said space; and
  • the adjusting means includes a member associated with each rigid profile which can be radially advanced through the profile against the roll bodies to set the compression between the roll bodies.
  • said rigid profile is an angle profile having an axial profile leg extending parallel and at a distance from the slats and a radial profile leg pointing inwardly, thereby restraining the roll bodies in one axial direction;
  • the axial retaining means further including a radially extending cover profile opposite said radial profile leg;
  • the roll bodies have a diameter greater than one-half the radial width of said annular space, but smaller than said width, the roll bodies being arranged to alternately bear against either the axial profile leg or a segmental slat.
  • the roll bodies have a diameter greater than one-half the radial width of said annular space, but smaller than said width, the roll bodies being arranged to alternately bear against either said rigid profile or a segmental slat;
  • said axial restraining means includes a cage of the kind used in anti-friction bearings.
  • said roll bodies are cylindrical rollers and said adjusting means is a radial set screw engaging one of the rollers which does not bear against a slat.
  • the roll bodies are a series of elongated rollers extending in parallel alignment with the segmental slats over at least one-half of the length of the stator sleeve, the rollers being arranged proximate to each other in a circumferential row, with a small clearance allowing for their being drawn together when the intended diameter reduction of the stator sleeve is effected; and the compression transmitting means is in the form of at least two axially spaced non-stretchable annular members surrounding said rollers.
  • the compression transmitting means is in the form of at least two axially spaced non-stretchable annular members surrounding said rollers.
  • the compression adjusting means is combined with the compression transmitting means in the form of at least two substantially closed adjustable pipe clamps surrounding said rollers.
  • the roll bodies are a series of rollers whose axes extend in parallel alignment with the segmental slats, the rollers being arranged proximate to each other in a circumferential row;
  • the compression transmitting means is in the form of a chain-link-type connection between each adjacent roller pair, except one, thus forming a chain with two ends, said one roller pair being spaced apart to allow for the chain ends to be drawn together when the intended diameter reduction of the stator sleeve is effected;
  • the compression adjusting means is a means for forcion the circumference of the stator sleeve, the slats extending longitudinally over at least a major portion of the sleeve length; each slat being defined cross-sectionally by an arcuate inner slat portion and by an arcuateouter slat portion which are joined by an offset portion, the curvatures of these slat portions and the radial height of offset being such that, when an outer slat portion overlaps the inner slat portion of the next slat, said curvatures coincide approximately with three concentric, equidistant circles; and
  • stator sleeve means for radially compressing the stator sleeve through the application of radial pressure to said slats.
  • the offset portion of the segmental slat includes an inclined profile portion, the angle of incline in relation to the adjacent arcuate slat portions being comprised between and 45, preferably 21.
  • stator sleeve a rigid end ring at each axial end of the stator sleeve surrounding the latter; the segmental slats have an overall length to axially fit between the aforementioned end rings.
  • the overlapping segmental slats present an overall outer contour which includes a longitudinal groove between eachv end face of an outer slat portion and the offset portion of the next slat, the bottom of each groove being defined by the outer surface of an inner slat portion;
  • the means for radially compressing the stator sleeve includes:
  • each plane containing a series of balls equal in number to that of the segmental slats, each ball being confined in one of said grooves, bearing against its bottom;
  • each ball has a circumferential displacement clearance within its bounds which is at least equal to 0.5 times, and preferably between 0.8 and 1.5 times the ball diameter.
  • the approaching means includes an axially displaceable thrust ring surrounding the stator sleeve between one of said end rings and the nearest of said ring members and means for axially advancing said thrust ring toward the ring members, thereby creating longitudinal compression forces between said ring members and the other of said end rings with a resultant inwardly directed compression created against said balls and said slats.
  • said thrust ring advancing means including adjustment nuts arranged on the threaded clamping rods, the nuts cooperating with the thrust ring.
  • a radially compressible stator comprising in combination:
  • stator sleeve of a resiliently yielding material such as rubber and the like having a longitudinal cavity defined by a twin helix inside which may be received an eccentrically rotating helical screw; plurality of segmental slats of flat stock of a hard, highly pressure resistant material arranged on the circumference of the stator sleeve, the slats extending longitudinally over at least a major portion of the sleeve length and overlapping each other in the circumferential direction; each slat being defined cross-sectionally by an arcuate inner slat portion and by an arcuate outer slat portion which are joined by an offset portion, the curvatures of these slat portions and the radial height of offset ,being such that, when an outer slat portion overlaps the inner slat portion of the next slat, said curvatures coincide approximately with three concentric, equidistant circles.
  • segmental slats having an overall length to axially fit between the two end rings.
  • At least one of the end rings includes an axially inwardly facing centering collar whose inner diameter cooperates with the assembled outer diameter of the segmental slats so as to radially retain the latter.
  • the offset portion of the segmental slat includes an inclined profile portion, the angle of incline in relation to the adjacent arcuate slat portions being comprised between 20 and 45, preferably 30.
  • segmental slats are permanently attached to the outside of the stator sleeve by a bond, preferably of the vulcanized type, between their inner slat portions and the surface of the stator sleeve.
  • the bond between the inner slat portions and the surface of the stator sleeve is restricted to the longitudinal edges of the i me slat pgrtions.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Rotary Pumps (AREA)
US00325748A 1972-01-21 1973-01-22 Adjustable diameter stator for excentric helical screw pump Expired - Lifetime US3857654A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19722202763 DE2202763C3 (de) 1972-01-21 Nachstellbarer Stator für Exzenterschneckenpumpen
DE19722243479 DE2243479B2 (de) 1972-09-05 1972-09-05 Nachstellbarer stator fuer exzenterschneckenpumpen

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US3857654A true US3857654A (en) 1974-12-31

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US00325748A Expired - Lifetime US3857654A (en) 1972-01-21 1973-01-22 Adjustable diameter stator for excentric helical screw pump

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US (1) US3857654A (enrdf_load_stackoverflow)
FR (1) FR2175403A5 (enrdf_load_stackoverflow)
GB (1) GB1405339A (enrdf_load_stackoverflow)
IT (1) IT978275B (enrdf_load_stackoverflow)

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4313717A (en) * 1979-10-04 1982-02-02 Kopecky Eugene F Adjustable pressure extrusion pump
US4991292A (en) * 1988-07-30 1991-02-12 Gummi-Jager Kg Gmbh & Cie Method of producing elastomeric stators for eccentric helical pumps
US5171138A (en) * 1990-12-20 1992-12-15 Drilex Systems, Inc. Composite stator construction for downhole drilling motors
EP0612922A1 (en) * 1993-02-22 1994-08-31 Mono Pumps Limited Progressive cavity pump or motors
US5759019A (en) * 1994-02-14 1998-06-02 Steven M. Wood Progressive cavity pumps using composite materials
US6019583A (en) * 1994-02-14 2000-02-01 Wood; Steven M. Reverse moineau motor
US6183226B1 (en) 1986-04-24 2001-02-06 Steven M. Wood Progressive cavity motors using composite materials
US6439834B1 (en) * 1998-10-13 2002-08-27 Arthur Whiting Oil field tool
US20050089430A1 (en) * 2003-10-27 2005-04-28 Dyna-Drill Technologies, Inc. Asymmetric contouring of elastomer liner on lobes in a Moineau style power section stator
US20050147516A1 (en) * 2002-09-10 2005-07-07 Hisham Kamal Stator for eccentric spiral pump
US20060153724A1 (en) * 2005-01-12 2006-07-13 Dyna-Drill Technologies, Inc. Multiple elastomer layer progressing cavity stators
JP2007071208A (ja) * 2005-09-08 2007-03-22 Netzsch Mohnopumpen Gmbh ステータシステム
US20080008611A1 (en) * 2005-03-21 2008-01-10 Johann Kreidl Stator Clamping Device For Eccentric Screw Pump
US9393648B2 (en) 2010-03-30 2016-07-19 Smith International Inc. Undercut stator for a positive displacment motor
US10132313B2 (en) * 2015-12-25 2018-11-20 Heishin Ltd. Uniaxial eccentric screw pump
WO2021118533A1 (en) * 2019-12-10 2021-06-17 Circor Pumps North America, Llc Screw pump or machine
WO2025140053A1 (zh) * 2023-12-26 2025-07-03 中国石油天然气集团有限公司 用于量测粘性液体的可变径装置及粘度测量方法

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0083829A1 (en) * 1982-01-11 1983-07-20 Eugene F. Kopecky Adjustable pressure extrusion pump
UA119134C2 (uk) 2012-08-08 2019-05-10 Аарон Фьюстел Роторні пристрої з розширюваними камерами, що мають регульовані проходи для робочого плинного середовища, а також системи, що мають такі пристрої

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AT218386B (de) * 1959-06-11 1961-11-27 Seeberger K G Maschinen & Gera Schneckenpumpe
US3028812A (en) * 1960-03-01 1962-04-10 Scotti Ambrogio Hydraulic mechanical device for tightening tubular elastic elements
US3084631A (en) * 1962-01-17 1963-04-09 Robbins & Myers Helical gear pump with stator compression
US3435772A (en) * 1966-03-15 1969-04-01 Karl Schlecht Variable diameter stator for screw pump

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AT218386B (de) * 1959-06-11 1961-11-27 Seeberger K G Maschinen & Gera Schneckenpumpe
US3028812A (en) * 1960-03-01 1962-04-10 Scotti Ambrogio Hydraulic mechanical device for tightening tubular elastic elements
US3084631A (en) * 1962-01-17 1963-04-09 Robbins & Myers Helical gear pump with stator compression
US3435772A (en) * 1966-03-15 1969-04-01 Karl Schlecht Variable diameter stator for screw pump

Cited By (26)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4313717A (en) * 1979-10-04 1982-02-02 Kopecky Eugene F Adjustable pressure extrusion pump
US6183226B1 (en) 1986-04-24 2001-02-06 Steven M. Wood Progressive cavity motors using composite materials
US4991292A (en) * 1988-07-30 1991-02-12 Gummi-Jager Kg Gmbh & Cie Method of producing elastomeric stators for eccentric helical pumps
EP0353553A3 (de) * 1988-07-30 1992-02-05 Gummi-Jäger Kg Gmbh & Cie Verfahren zur Herstellung von Elastomerstatoren für Exzenterschneckenpumpen
US5171138A (en) * 1990-12-20 1992-12-15 Drilex Systems, Inc. Composite stator construction for downhole drilling motors
EP0612922A1 (en) * 1993-02-22 1994-08-31 Mono Pumps Limited Progressive cavity pump or motors
AU664507B2 (en) * 1993-02-22 1995-11-16 Mono Pumps Limited Progressive cavity pump or motors
US5474432A (en) * 1993-02-22 1995-12-12 Mono Pumps Limited Progressive cavity pump or motors
US5759019A (en) * 1994-02-14 1998-06-02 Steven M. Wood Progressive cavity pumps using composite materials
US6019583A (en) * 1994-02-14 2000-02-01 Wood; Steven M. Reverse moineau motor
US6439834B1 (en) * 1998-10-13 2002-08-27 Arthur Whiting Oil field tool
US20050147516A1 (en) * 2002-09-10 2005-07-07 Hisham Kamal Stator for eccentric spiral pump
JP2005538298A (ja) * 2002-09-10 2005-12-15 ネッチュ−モーノプンペン ゲーエムベーハー 偏心スパイラルポンプ用ステータ
US7137795B2 (en) * 2002-09-10 2006-11-21 Netzsch-Mohnopumpen Gmbh Stator for eccentric spiral pump
US20050089430A1 (en) * 2003-10-27 2005-04-28 Dyna-Drill Technologies, Inc. Asymmetric contouring of elastomer liner on lobes in a Moineau style power section stator
US7083401B2 (en) 2003-10-27 2006-08-01 Dyna-Drill Technologies, Inc. Asymmetric contouring of elastomer liner on lobes in a Moineau style power section stator
US20060153724A1 (en) * 2005-01-12 2006-07-13 Dyna-Drill Technologies, Inc. Multiple elastomer layer progressing cavity stators
US7517202B2 (en) 2005-01-12 2009-04-14 Smith International, Inc. Multiple elastomer layer progressing cavity stators
US20080008611A1 (en) * 2005-03-21 2008-01-10 Johann Kreidl Stator Clamping Device For Eccentric Screw Pump
US7871253B2 (en) * 2005-03-21 2011-01-18 Netzsch-Mohnopumpen Gmbh Stator clamping device for eccentric screw pump
JP2007071208A (ja) * 2005-09-08 2007-03-22 Netzsch Mohnopumpen Gmbh ステータシステム
US9393648B2 (en) 2010-03-30 2016-07-19 Smith International Inc. Undercut stator for a positive displacment motor
US10132313B2 (en) * 2015-12-25 2018-11-20 Heishin Ltd. Uniaxial eccentric screw pump
WO2021118533A1 (en) * 2019-12-10 2021-06-17 Circor Pumps North America, Llc Screw pump or machine
US12012957B2 (en) 2019-12-10 2024-06-18 Circor Pumps North America, Llc. Screw pump or machine with a liner that bends and/or pivots with the rotors
WO2025140053A1 (zh) * 2023-12-26 2025-07-03 中国石油天然气集团有限公司 用于量测粘性液体的可变径装置及粘度测量方法

Also Published As

Publication number Publication date
GB1405339A (en) 1975-09-10
IT978275B (it) 1974-09-20
FR2175403A5 (enrdf_load_stackoverflow) 1973-10-19

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