Classifications

• • 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
• • 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
  • F04C2230/00—Manufacture
  • F04C2230/20—Manufacture essentially without removing material
  • F04C2230/23—Manufacture essentially without removing material by permanently joining parts together
  • F04C2230/231—Manufacture essentially without removing material by permanently joining parts together by welding
• • 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
  • F04C2240/00—Components
  • F04C2240/20—Rotors
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T29/00—Metal working
  • Y10T29/49—Method of mechanical manufacture
  • Y10T29/49229—Prime mover or fluid pump making
  • Y10T29/49236—Fluid pump or compressor making
  • Y10T29/49242—Screw or gear type, e.g., Moineau type
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T29/00—Metal working
  • Y10T29/49—Method of mechanical manufacture
  • Y10T29/49826—Assembling or joining
  • Y10T29/49863—Assembling or joining with prestressing of part
  • Y10T29/49865—Assembling or joining with prestressing of part by temperature differential [e.g., shrink fit]

Definitions

• the pump or the motor has a stator with a continuous helical opening in which the rotor rolls during operation.
• the stator is formed by a cylindrical tube, which is provided with an elastomeric lining.
• the elastomeric lining itself represents the wall of the through opening and acts as a seal against the stator.
• the stator is composed of a core element and a jacket formed around it.
• the jacket is cold formed into a helical shape from a cylindrical tube. This gives the originally Lindwitz Rohr not only the helical shape, as required for the rotor, but the tube is also firmly connected to the core element in this way.
• the threaded valleys of the stator casing lie firmly and frictionally on the core element.
• the carrier element can also be provided with longitudinal ribs.
• the known rotor is inexpensive to manufacture in very large quantities. Lengths of up to 6 meters can easily be achieved without the need for machining the surface of the stator.
• the surface of the rotor is very smooth and sufficiently dimensionally stable.
• the core element present in the casing prevents the rotor from unwinding when pressure is applied, which would lead to a pitch error between the stator and rotor and the result of corresponding leaks.
• the steel material previously used for the known rotor is not strong enough for a number of applications with regard to the abrasion that occurs and for some applications it is also not sufficiently corrosion-resistant. In other words, the known rotor does not have sufficient erosion resistance.
• erosion is not only to be understood as the erosion caused by corrosion, but also the erosion caused by surface grinding of the material being conveyed.
• the method is characterized by the features of claim 23.
• the rotor is constructed in a sandwich-like manner. It consists of a radially inner layer and a radially outer layer, the radially outer layer being specially adapted to the higher erosion resistance. It can be more resistant to abrasion or corrosion or both than the radially inner layer. Since, moreover, the more corrosion-resistant materials can be formed with greater wall thickness under certain circumstances and / or are much more expensive than the radially inner layer, the radially inner layer can be selected primarily from the point of view of strength and cost, so that with a very thin radial outer layer the civil is found.
• a very homogeneous structure of the rotor can be achieved if the inner tube is a seamless tube. This avoids inhomogeneities that would otherwise occur during welding. Such inhomogeneities could continue as outward design errors.
• a coiled tube as the inner tube.
• the tube is preferably laser welded to the helical butt joint.
• the helix should run in the opposite direction to the helix of the outer layer.
• the inner layer, or the inner tube consists of an easily formable steel that is well suited to dissipating the forces that occur and that can be cold formed in a useful manner.
• the outer layer can consist of an attached pipe.
• such a solution is only suitable for rotors with a short overall length.
• the metal strip is wound up in a butt joint in such a way that the individual turns adjoin one another without a gap.
• a particularly good arrangement is achieved if the helical butt joint is on before cold forming who butt the turns, is welded.
• the welding is preferably carried out using a laser.
• Stainless steel V2A, V4A steel or other abrasion-resistant steels can be used as the outer material. Since these have a much higher specific weight than normal steel, the two-layer structure also means a weight saving compared to a rotor made only of stainless steel. This plays a role in rotors up to 6 meters long.
• the strength of the rotor can be improved if it has a core element.
• the rotor can be molded around the core element so that there is a good connection to the core element. With long lengths, the core element prevents the rotor from uncoiling under load. In addition, additional torque can be introduced over the length of the rotor with the aid of the core element.
• the essentially rotationally symmetrical and not helically deformed core is more suitable for this.
• the core element can itself be tubular or solid.
• the space between the tube or jacket of the rotor and the core element can either be left blank or filled with a mass.
• a cylindrical tube is first provided.
• the tube is covered with a metal layer, so that a double-walled structure is obtained.
• the double-walled structure which is still cylindrical, is then screwed over shapes
• the coating of the cylindrical tube with the outer layer is very simple and can also be easily accomplished because of the simple geometric shape of the tube provided.
• the outer layer only has to be applied with a smaller wall thickness, because the stability of the rotor may be primarily generated by the inner tube, materials can also be used for the outer layer that would no longer be cold-formed with a large wall thickness ,
• a seamless tube is advantageously used in the method according to the invention.
• the seamless tube expediently has a bright metallic surface, so that the connection of the outer layer to the tube is not hindered by oxide residues due to the cold forming.
• the outer metal layer consists of a metal strip that is wound onto the pipe.
• the metal strip can be heated immediately before the point of contact before winding. The subsequent cooling ensures a shrinking process that holds the metal strip particularly firmly on the surface of the pipe.
• the butt joint between adjacent turns is expediently welded to prevent particles from penetrating.
• the double-walled structure obtained is cold-formed.
• the outer layer connects, at least selectively, to the inner tube, similarly to the case with leafing. The connection is therefore particularly durable and will not open even when the temperature changes.
• a core element can be inserted before the coated tube is formed.
• Fig. 1 is an eccentric screw pump in a perspective view, partially cut
• Fig. 4 shows a cross section through the rotor of Fig. 3
• Fig. 5 shows the inventive method for producing the Rotor of the eccentric screw pump or of the eccentric screw motor according to Figure 1 with the process steps symbolized
• the eccentric screw pump 1 shows, in a schematic, perspective illustration, an eccentric screw pump 1 according to the invention.
• the eccentric screw pump 1 includes a pump head 2, a stator 3, in which a rotor 4, shown broken off in FIG. 2, rotates, and a connection head 5.
• the pump head 2 has an essentially cylindrical housing 6, which is provided at one end with an end cover 7, through which a drive shaft 8 is sealed to the outside.
• the end of the housing 6 remote from the cover 7 is provided with a clamping flange 12, the diameter of which is larger than the diameter of the essentially cylindrical housing 6.
• the clamping flange 12 contains a stepped bore 13 which is flush with the interior of the housing 6.
• a non-recognizable contact shoulder is formed in the stepped bore, against which the stator 3 is pressed at one end.
• connection head 5 has a clamping flange 14 which also interacts with the clamping flange 12 contains a stepped bore in which the other end of the stator 3 is inserted.
• a pipeline 15 leading away is aligned with the stepped bore.
• the stator 3 is tightly clamped with the aid of a total of 4 tie rods 16.
• the two clamping flanges 12 and 14 are each provided with four mutually aligned bores 17 which lie on a pitch circle which is larger than the outer diameter of the housing 6 or the pipe 15. The bores 17 lead through these bores 17 rod-shaped tie rod 16 therethrough.
• 16 nuts 18 are screwed onto the tie rods 16, with the aid of which the two clamping flanges 12 and 14 are tightened towards one another.
• the stator 3 consists of a tubular jacket 19 with a constant wall thickness, which surrounds an interior 20.
• the jacket 19 consists of steel, a steel alloy, light metal or a light metal alloy. It is shaped in such a way that its inner wall 21 takes the form of a multi-start screw. Its outer side 22 has a correspondingly similar shape with a diameter which, in accordance with the wall thickness of the jacket 19, is larger than the diameter of the interior of the jacket 19.
• the jacket 19 ends at its ends with end faces 23 and 24 which run at right angles with respect to its longitudinal axis 25 ,
• the longitudinal axis 25 is the axis of the interior 20.
• the interior 20 has the shape a two-start screw.
• the cross section surrounded by the outer surface 22, viewed at right angles to the longitudinal axis 25, has the shape of an oval, similar to a racetrack.
• a closing or reducing ring 26 is seated on the jacket 19 on each end face.
• the ends can also be shaped into cylindrical tubes.
• the end ring 26 contains a through opening 27 which corresponds to the course of the outer surface 22 over the length of the end ring 26.
• the end ring 26 acts in the broadest sense like a nut which is screwed onto the thread which is defined by the jacket 19.
• the length of the thread corresponds to the thickness of the end ring 26.
• the end ring 26 is delimited radially outwards by a cylindrical surface 28 which merges in the axial direction into a flat surface 29 which points away from the jacket 19.
• the jacket 19 is provided with a continuous lining 32 over its entire length.
• the lining 32 consists of an elastically resilient, preferably elastomeric material, for example natural rubber or synthetic material, and has approximately the same wall thickness at each point.
• the rotor 4 is composed of a core element 33, a rotor jacket 34 and a coupling head 35.
• the core element 33 is a thick-walled steel tube with an at least originally cylindrical outer peripheral surface 36 and a continuous cylindrical interior 37.
• the core element 33 is straight and therefore tubular, because the interior does not make any noteworthy contribution to the strength at issue, but only increases the weight. However, it can also be massive.
• the core element 33 is provided with a threaded pin 38. At the opposite end, the core element 33 contains a threaded bore 39.
• the jacket 34 of the rotor 4 is also a tube with an inner wall 40 and an outer surface 41.
• the outer surface 41 forms a thread that continues over the entire axial length of the jacket 34. It begins at 42 and ends at 43.
• the number of threads of the thread formed by the outer surface 41 is one less than the number of threads of the through opening 20 in the stator 3.
• the rotor 4 has a four-start thread in the exemplary embodiment shown, i.e. a total of four strips run helically along the jacket 34. Since the through-opening 20 is accordingly five-thread, the five-thread in the through-hole 20 forms a total of five helically extending strips made of elastomer material.
• the cross section through the rotor 4 is shown in FIG.
• the rotor jacket 34 has two layers and consists of an inner layer 44 and an outer layer thereon Layer 45.
• the inner layer 44 consists of an originally cylindrical steel tube with good deformability and a strength suitable for the application.
• the outer layer 45 consists of an erosion-resistant material, that is to say a material that little is removed or ground off by the medium to be pumped and / or that is chemically little attacked by the medium to be pumped.
• a suitable material is, for example, stainless steel such as a V2A or a V4A.
• the wall thickness of the inner layer 44 is between 1 mm and 5 mm, while the wall thickness of the outer layer 45 can be between 1 mm and also 5 mm. The manufacture of this rotor 4 is explained below with reference to FIG. 5.
• the jacket 34 is, as already mentioned, tubular, which is why the inner surface 40 follows the outer surface 41 at a constant distance.
• the dimensions of the cylindrical straight tube from which the jacket 34 is cold-formed are selected such that after the final deformation into the screw-like shape, the jacket 34 with its inner peripheral surface 40 in the area of the threaded troughs 47 (based on the outer contour), the outer peripheral surface 36 of the core element 33 at least touched.
• the semifinished product from which the jacket 34 is made is a cylindrical tube, the diameter of which is larger than the outer diameter of the core element 33, helical gaps 49 are formed between the core element 33 and the jacket 34.
• the number of these helical gaps 49 is equal to the number of thread crests 46 which can be seen in the cross-section of the rotor 4 in the circumferential direction.
• these spaces 49 can either remain empty or be filled with a mass. This mass can e.g. Synthetic resin or synthetic resin filled with light metal powder.
• a bright drawn, seamless steel tube 51 with a suitable wall thickness and a suitable length of several meters provided.
• the steel tube 51 is wound on the outside with a metal strip 52, which later forms the outer layer 45.
• the metal band 52 is a band made of a corresponding stainless steel or other steel.
• the band 42 is wound onto the outside of the steel tube 51 as a single screw. It forms turns 53 lying side by side, which are separated from one another by a helical butt joint 54.
• the metal strip 52 is wound in such a way that the butt joint 54 is closed as far as possible.
• the butt joint 54 is welded during winding or in a separate step using a laser beam 55 and filler material in order to achieve a smooth, homogeneous cylindrical surface. Other welding processes are also possible. It can be welded through in order to connect the band 52 in the area of the butt joint 54 to the support tube 51 in a cohesive manner.
• the metal strip 52 Immediately before the metal strip 52 hits the tube 51, it is heated, for example by means of a gas flame 56 or inductively. It is thereby achieved that the metal strip 52 generates a considerable tension in the circumferential direction after the winding on the tube 51 and the cooling.
• the core element 33 is inserted as shown in FIG.
• the structure is then cold-worked, for example rolling using a large number of rollers, only one of which is indicated at 57, brought into the desired screw shape -
• the metal strip 52 connects very intimately to the outer surface of the steel tube 51 located underneath.
• the metal strip 52 forms a second, outer tube on the metal steel tube 51, which sits tightly and frictionally in the circumferential direction on the outer peripheral surface of the tube 51.
• the two tubes namely the tube created by winding and the seamless inner steel tube, are so firmly connected to one another after winding that they can no longer be separated.
• the subsequent rolling process according to FIG. 7 ensures an even more intimate connection which, at least to a certain extent, resembles the plating of a metal layer.
• the rolling which in itself leads to a stretching of a piece of metal, surprisingly does not separate the outer tube produced by winding from the tube 51 located underneath. Rather, both are formed together into the desired screw shape, with the intimate connection also being formed at the same time the core element 33 is produced.
• An eccentric screw pump or an eccentric screw motor has a rotor which is formed from an at least two-layer tubular jacket.
• the outer layer of the jacket is made of a material that is resistant to abrasion and / or corrosion.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Rotary Pumps (AREA)
• Details And Applications Of Rotary Liquid Pumps (AREA)

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• 2003
  • 2003-08-22 DE DE10338632A patent/DE10338632B4/de not_active Expired - Fee Related
• 2004
  • 2004-08-14 US US10/569,247 patent/US7909591B2/en not_active Expired - Fee Related
  • 2004-08-14 RU RU2006109022/06A patent/RU2340793C2/ru not_active IP Right Cessation
  • 2004-08-14 ES ES04764133T patent/ES2300811T3/es not_active Expired - Lifetime
  • 2004-08-14 EP EP04764133A patent/EP1656502B1/fr not_active Expired - Lifetime
  • 2004-08-14 WO PCT/EP2004/009141 patent/WO2005021971A1/fr active IP Right Grant
  • 2004-08-14 BR BRPI0413690A patent/BRPI0413690B1/pt not_active IP Right Cessation
  • 2004-08-14 PT PT04764133T patent/PT1656502E/pt unknown
  • 2004-08-14 CA CA2535870A patent/CA2535870C/fr not_active Expired - Fee Related
  • 2004-08-14 DE DE502004006140T patent/DE502004006140D1/de not_active Expired - Lifetime
  • 2004-08-14 AT AT04764133T patent/ATE385544T1/de active

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