CA2308164A1 - Drive head for a rotary-driven rod assembly, especially for driving a sand pump - Google Patents
Drive head for a rotary-driven rod assembly, especially for driving a sand pump Download PDFInfo
- Publication number
- CA2308164A1 CA2308164A1 CA002308164A CA2308164A CA2308164A1 CA 2308164 A1 CA2308164 A1 CA 2308164A1 CA 002308164 A CA002308164 A CA 002308164A CA 2308164 A CA2308164 A CA 2308164A CA 2308164 A1 CA2308164 A1 CA 2308164A1
- Authority
- CA
- Canada
- Prior art keywords
- housing
- rod string
- stator
- drive head
- sleeve
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 239000004576 sand Substances 0.000 title 1
- 230000008878 coupling Effects 0.000 claims abstract description 8
- 238000010168 coupling process Methods 0.000 claims abstract description 8
- 238000005859 coupling reaction Methods 0.000 claims abstract description 8
- 230000007246 mechanism Effects 0.000 claims description 15
- 230000009467 reduction Effects 0.000 abstract description 2
- 239000012530 fluid Substances 0.000 description 12
- 238000005192 partition Methods 0.000 description 7
- 230000005540 biological transmission Effects 0.000 description 4
- 230000004048 modification Effects 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 230000000903 blocking effect Effects 0.000 description 2
- 230000000875 corresponding effect Effects 0.000 description 2
- 230000001419 dependent effect Effects 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 241000901720 Stator Species 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 230000005489 elastic deformation Effects 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 238000010008 shearing Methods 0.000 description 1
- 238000000638 solvent extraction Methods 0.000 description 1
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
- F04C14/00—Control of, monitoring of, or safety arrangements for, machines, pumps or pumping installations
- F04C14/28—Safety arrangements; Monitoring
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/12—Methods or apparatus for controlling the flow of the obtained fluid to or in wells
- E21B43/121—Lifting well fluids
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B47/00—Pumps or pumping installations specially adapted for raising fluids from great depths, e.g. well pumps
- F04B47/02—Pumps or pumping installations specially adapted for raising fluids from great depths, e.g. well pumps the driving mechanisms being situated at ground level
-
- 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
- F04C15/00—Component parts, details or accessories of machines, pumps or pumping installations, not provided for in groups F04C2/00 - F04C14/00
- F04C15/0057—Driving elements, brakes, couplings, transmission specially adapted for machines or pumps
-
- 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
- F04C2270/00—Control; Monitoring or safety arrangements
- F04C2270/70—Safety, emergency conditions or requirements
- F04C2270/72—Safety, emergency conditions or requirements preventing reverse rotation
Landscapes
- Engineering & Computer Science (AREA)
- Geology (AREA)
- Life Sciences & Earth Sciences (AREA)
- Mining & Mineral Resources (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Fluid Mechanics (AREA)
- Environmental & Geological Engineering (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Physics & Mathematics (AREA)
- Braking Arrangements (AREA)
- Details And Applications Of Rotary Liquid Pumps (AREA)
- Details Of Reciprocating Pumps (AREA)
- Connection Of Motors, Electrical Generators, Mechanical Devices, And The Like (AREA)
Abstract
The invention relates to a drive head, comprising a housing (12) with passages (24, 26) for the rod assembly (10) and a rotary-driven sleeve (30) which is arranged in said housing. Said sleeve (30) surrounds a section of the rod assembly (10) and is connected thereto by a coupling (40). A recoil brake (70) is provided for the controlled reduction of the torsion energy accumulated in the rod assembly. Said recoil brake (70) has a rotor (74) which is driven by means of the sleeve (30) and a stator (76) which is supported on the housing (12). The stator (76) is prevented from turning in relation to the housing (12) by a lock (82) which can only be released when the assembly (10) is essentially free of torsion energy. This ensures that it is safe to check whether the torsion energy has been essentially reduced.
Description
A drive head for a rod string adapted to be driven in rotation, especially for driving a downhole pump.
The invention relates to a drive head as defined in the preamble of claim 1.
When loaded with a torque to be transmitted, a rod string used in a well bore which typically is of great length as compared to its diameter will suffer elastic twisting and, as a conse-quence, it will store elastic deformation energy which may become released all of a sudden when the torque load ceases to exist. The deformation energy which also may be referred to as torsional energy depends on the torque introduced and on the length of the rod string. In the case of a drive head of the kind mentioned the torque is transmitted, for example, from an electric motor via a gear unit having a speed reduction ratio of 4:1 to the sleeve and then on through the rod string to a pump rotor connected to the lower end thereof. The rod string may have a length of more than one thousand meters. When the rod string is loaded with the maximum permissible torque the resulting twisting of the rod string from the sleeve down to the lower end may well amount to 100 turns or more. If the motor then is switched off, or if it should fail because of a defect, care must be taken that the torsional energy stored in the rod string is not set free suddenly. The need for a cor-responding precautionary measure has led to equipping drive heads of the generic kind in question with a recoil brake, em-bodied by a fluid brake, which is constantly ready to enter into operation.
With a known drive head of the kind in question (DE 196 16 578 C1) the recoil brake comprises an hydraulic circuit including a pump with a rotor and a throttle. A directional locking gear mechanism connects the rotor to the sleeve in torque trans-mitting fashion during back-spin only, the sleeve driving the rod string during normal operation.
The invention relates to a drive head as defined in the preamble of claim 1.
When loaded with a torque to be transmitted, a rod string used in a well bore which typically is of great length as compared to its diameter will suffer elastic twisting and, as a conse-quence, it will store elastic deformation energy which may become released all of a sudden when the torque load ceases to exist. The deformation energy which also may be referred to as torsional energy depends on the torque introduced and on the length of the rod string. In the case of a drive head of the kind mentioned the torque is transmitted, for example, from an electric motor via a gear unit having a speed reduction ratio of 4:1 to the sleeve and then on through the rod string to a pump rotor connected to the lower end thereof. The rod string may have a length of more than one thousand meters. When the rod string is loaded with the maximum permissible torque the resulting twisting of the rod string from the sleeve down to the lower end may well amount to 100 turns or more. If the motor then is switched off, or if it should fail because of a defect, care must be taken that the torsional energy stored in the rod string is not set free suddenly. The need for a cor-responding precautionary measure has led to equipping drive heads of the generic kind in question with a recoil brake, em-bodied by a fluid brake, which is constantly ready to enter into operation.
With a known drive head of the kind in question (DE 196 16 578 C1) the recoil brake comprises an hydraulic circuit including a pump with a rotor and a throttle. A directional locking gear mechanism connects the rotor to the sleeve in torque trans-mitting fashion during back-spin only, the sleeve driving the rod string during normal operation.
Another known drive head of the kind in question (DE 196 28 950 A1) is provided with a recoil brake embodied by a hydrody-namic retarder which includes a rotor impeller and a stator impeller together defining a toroidal work chamber which is constantly filled with fluid during operation. A power unit for propelling the rod string is in constant driving connec-tion, at least indirectly, with the rotor impeller. The blades of the rotor and stator impellers are inclined with respect to a partitioning plane between the two impellers such that the rotor impeller will rotate substantially in freewheeling fashion, due to the blade direction, when the rod string is driven by the power unit. If, on the other hand, the flux of force from the power unit is interrupted as restoring torques act on the rod string, a brake torque is generated between the rotor impeller and the stator impeller.
Another known drive head for a well bore rod string (GB 2 299 849 A) likewise is equipped with a recoil brake in the form of a hydrodynamic retarder including a rotor impeller and a sta-tor impeller. The rotor impeller is connected by a mechanical directional locking gear mechanism to a sleeve which encloses the rod string so that the rotor impeller will be driven only during back-spin.
As is well known, quick deceleration of high kinetic energy masses can be accomplished also by visco brakes (DE 39 09 231 A1). However, as far as can be seen, brakes of this kind have not yet been suggested for use as recoil brakes with rod strings adapted to be driven in rotation, especially not for rod strings in well bores.
It is common to all fluid brakes that their braking efficiency is dependent more or less upon temperature. That may become a problem when a fluid brake is used as recoil brake for a well bore rod string because drive heads of well bore rod strings often are employed at extreme temperatures and, in some places, at extremely great differences between day and night time temperatures. The temperature dependence of fluids such as normally used for fluid brakes thus may have the conse-quence that a fluid which is suitable for average temperatures or high temperatures, for example, will become so viscous at low temperatures that the recoil brake cannot provide suffi-cient dissipation of torsional energy stored in a well bore rod string to permit risk-free working at the drive head.
It is, therefore, the object of the invention to furnish a drive head for a rod string adapted to be driven in rotation, especially for driving a downhole pump, with a recoil brake at which it can be verified without any risk whether or not the torsional energy has been substantially dissipated.
The object is met, in accordance with the invention, by the features recited in claim 1. Advantageous further developments are the subject matter of the dependent claims.
Embodiments of the invention will be described in greater detail below, with reference to diagrammatic drawings, in which:
Fig. 1 is a vertical axial elevation of a drive head according to the invention;
Fig. 2 shows an enlarged cutout of fig. 1;
Fig. 3 shows a first modification of fig. 2;
Fig. 4 shows a second modification of fig. 2.
The drive head illustrated in fig. 1 serves to rotate a ver-tical rod string 10 extending from the surface of the ground down into a well bore and being connected at its bottom end to a pump rotor (not shown), for instance, a helical rotor of an eccentric worm type pump. The housing 12 encloses a gear cham-ber 14, a substantially horizontal partition 16 separating the gear chamber 14 from a seal chamber 18 located underneath it, and a locking gear and brake chamber 20 likewise located under the gear chamber 14 and separated from the seal chamber 18 beside it by a vertical partition 22. The housing 12 is formed with a lower passageway 24 and an upper passageway 26 ver-tically above it. The rod string 10 can be lowered and raised through these passageways. An oil aperture 28 provides con-stant communication between the gear chamber 14 and the locking gear and brake chamber 20 which are substantially filled with transmission oil. The seal chamber 18 contains a blocking fluid whose level can be monitored through a monitor-ing means (not shown), such as a sight glass or a sensor.
A sleeve 30 extends vertically from above through the upper passageway 26 down into the gear chamber 14 and further through the horizontal partition 16 into the seal chamber 18.
The sleeve 30 is supported in the partition 16 by a lower radial bearing 32 and immediately above it by an axial bearing 34. Moreover, it is supported in the upper passageway 26 of the housing 12 by means of an upper radial bearing 36. Above the housing 12, the sleeve is connected to the rod string 10 by a coupling 40 of conventional structure so as to transmit torque. The coupling 40 is releasable in order to permit raising or lowering of the rod string 10. A lower end portion of the sleeve 30 is enclosed by a cup-shaped insert 42 intro-duced into the housing 12 through the lower passageway 24, screw-connected to the housing, and sealed. The insert 42 is sealed with respect to the sleeve 30 by a lower slide ring seal 44 enclosed by the insert. An upper slide ring seal 46 is located spaced above the same and seals the sleeve 30 against the horizontal partition 16.
A gearing shaft 48 constituting part of a gear transmission 50 is disposed parallel to and spaced from the sleeve 30. It serves to transmit motion to the sleeve 30 and thus to the rod string 10 from a motor (not shown) arranged outside of the housing 12, for example an electric motor. The gearing shaft 48 is supported in the housing 12 by a lower bearing 52 and an upper bearing 54 and, between the two, it has a pinion 56 fastened to the shaft or, alternatively, formed integral with the same, as shown in the drawing, and constantly meshing with gear 38. The gearing shaft 48 includes a journal 58 extending downwardly beyond the lower bearing 52 and carrying a direc-tional locking gear 60.
The directional locking gear 60 comprises two bearings 62 arranged axially spaced apart on the journal 58 and an inner bushing 64 disposed between the two bearings for joint rota-tion with the journal 58. The inner bushing 64 is enclosed by an outer bushing 66 which is radially spaced from the inner bushing and supported on the two bearings 62. The two bushings 64 and 66 are coaxial with the gearing shaft 48 and define an annular space in which clamping rollers 68 responsive to the direction of rotation are housed. In the rotational operating direction of the gearing shaft 48 the directional locking gear 60 thus constituted acts as a freewheel device. On the other hand, it acts in blocking sense, driving a brake shaft 72 which belongs to a recoil brake 70 when the gearing shaft 48 is driven in opposite direction. The brake shaft 72 is flange-connected to the outer bushing 66 and carries a rotor 74 connected for joint rotation with the brake shaft 72 by means of a multi-groove profile, for example, the rotor being en-closed by a stator 76.
In the case of the drive head illustrated in figs. 1 and 2 the recoil brake 70 is a modified visco coupling such as normally used in the power train of four wheel drive motor vehicles. As shown, the modification may reside in no more than providing that part of a conventional visco coupling which serves as stator 76 in the coupling according to the invention with a flange 78 which is coaxial with the brake shaft 72. In the em-bodiment shown, the flange 78 is screw-connected to the stator 76. The flange 78 is responsible for centering the stator 76 in a bearing means 80 with respect to the brake shaft 72 and, upon release of a locking mechanism 82, it is held so as to be rotatable together with the brake shaft 72.
The locking mechanism 82 serves normally to firmly hold the stator 76 and prevent it from rotating, in other words to connect it rigidly to the housing 12, together with the bearing means 80. In all the embodiments shown, the locking mechanism 82 comprises a pawl 84 which is guided for radial displacement within the housing 12 and normally acts on or engages in a seat 86 associated with the stator 76. According to figs. 1 and 2 the seat 86 is a radial bore in the flange 78. Alternatively, the pawl 84 could be guided in a bore of the housing 12 parallel to the brake shaft 72 and thus engage in a paraxial bore or other seat 86 in the flange 78 or stator 76 itself.
In all the embodiments illustrated, the pawl 84 extends through the housing 12, having a head 88 at the outside thereof. A spring 90 is arranged between the housing 12 and the head 88, biasing the pawl 84 in outward direction in the sense of releasing the lock. Unintentional release of the locking mechanism 82 is excluded by any kind of suitable safety measure. In all the embodiments shown, a cover 92 shaped like a bow is provided for this purpose. It is fastened to the housing 12 by screws 94 and made tamper-proof by provi-sion of a lead seal 96. A switch 98 is fixed to the cover 97.
It will not release energy for supply to the motor (not shown) unless the pawl 84 and the cover 92 are in their normal posi-tions as illustrated, i.e. unless the locking mechanism 82 is effectively and verifiably secured.
With the locking mechanism 82 in this effective condition, torsional energy stored in the rod string 10 cannot be dissi-pated unless the rotor 74, propelled by the brake shaft 72, rotates with respect to the stator 76. This rotation can be rendered detectable from outside, e.g. by providing the housing 12 with a sight glass through which the rotor 74 can be observed.
When the torsional energy built up in the rod string 10 has been substantially dissipated and, consequently, rotation of the rotor 74 has stopped or dropped to a rotational speed no longer well noticeable, the cover 92 may be lifted off to examine, without any risk, whether perhaps a remainder of torsional energy worth mentioning still is stored in the rod string 10. After removal of the cover 92, if the bias of the spring 90 suffices to lift the pawl 84 off its seat 86, that is an indication that the torque acting on the stator 76, having come from the brake shaft 72 and through the rotor 74, has become so small that the corresponding tangential force transmitted from the seat 86 to the pawl 84 no longer can generate sufficient friction to hold the pawl 84 against the bias of the spring 90. On the other hand, if the locking mechanism 82 does not become released automatically once the cover 92 has been screwed off, this is an indication that per-haps a dangerous rest of torsional energy still may be contained in the rod string 10. That can be dissipated by enhancing the torque caused by the residual torsional energy by applying a screw driver to the gearing shaft 68 to turn the rotor 74 somewhat further than it already did itself with respect to the stator 76 which continues to be locked, turning the rotor against the shearing resistance of the fluid con-tained in the recoil brake 70.
The embodiment illustrated in fig. 3 essentially differs from the one according to figs. 1 and 2 in that the recoil brake 70 is a hydrodynamic brake. In this case the stator 76 is formed directly with the flange 78 for the bearing means 80 and the seat 86 for the pawl 84. While the visco brake shown in figs.
1 and 2, constituting the recoil brake 70, is provided in the usual manner with rotor fins 100 and stator fins 102 of the type which is conventional with visco brakes, the embodiment according to fig. 3 comprises rotor blades 104 and stator blades 106 of the structure which is usual with hydrodynamic retarders.
As regards the locking mechanism 82, fig. 4 does not differ from fig. 3. However, according to fig. 4 the rotor 74 is formed at regular angular spacings with a plurality of radial cylinders 108, for example six, each containing a piston 110.
Each piston 110 is biased radially outwardly by a spring 112 and is supported through a slide member 114 on an annular-oval race 116 which belongs to the stator 76. During each full rotation of the rotor 74, therefore, each piston 110 carries out a reciprocating motion. Next to the rotor 74 there is a control member 118 which is resiliently biased axially towards the rotor and secured against rotation on the stator 76.
A throttle 120 forming part of a hydraulic circuit is disposed radially outside of the control member 118. The hydraulic circuit further comprises an inlet passage 122 which leads from the locking gear and brake chamber 20 through the stator 76 and the control member 118 to the cylinder 108, and an out-let passage 124 which leads from the cylinder 108 through the control member 118 and the stator 76 to the throttle 120. The fluid being pumped passes through the throttle 120 and then flows into the locking gear and brake chamber 20. The oil aperture 28 permits constant exchange of fluid between the gear chamber 14 and the locking gear and brake chamber 20. As a result, the heat originating from the throttling is distri-buted in all of the fluid of which the major portion is con-tained in the gear chamber 14 in the embodiment illustrated, thus serving to lubricate the gear transmission 50.
In all the embodiments shown, the directional locking gear 60 and the recoil brake 70 are installed in the housing 12 from below through an opening subsequently closed by a cover 126.
An adapter 128 which is coaxial with the rod string 10 like-wise is connected via a flange to the bottom of the housing 12. This adapter carries the entire drive head and secures it against rotation.
List of reference numerals rod string 70 recoil brake 12 housing 72 brake shaft 14 gear chamber 74 rotor 16 partition 76 stator 18 seal chamber 78 flange brake chamber 80 bearing means 22 partition 82 locking mechanism 24 lower passageway 84 pawl 26 upper passageway 86 seat 28 oil aperture 88 head sleeve 90 spring 32 lower radial bearing 92 cover 34 axial bearing 94 screws 36 upper radial bearing 96 lead seal 38 98 switch coupling 100 rotor fins 42 cup-shaped insert 102 stator fins 44 lower slide ring seal 104 rotor blades 46 upper slide ring seal 106 stator blades 48 gearing shaft 108 radial cylinders gear transmission 110 piston 52 lower bearing 112 spring 54 upper bearing 114 slide member 56 pinion 116 race 58 journal 118 control member directional locking gear 120 throttle 62 bearing 122 inlet passage 64 inner sleeve 124 outlet passage 66 outer sleeve 126 cover 68 clamping rollers 128 adapter
Another known drive head for a well bore rod string (GB 2 299 849 A) likewise is equipped with a recoil brake in the form of a hydrodynamic retarder including a rotor impeller and a sta-tor impeller. The rotor impeller is connected by a mechanical directional locking gear mechanism to a sleeve which encloses the rod string so that the rotor impeller will be driven only during back-spin.
As is well known, quick deceleration of high kinetic energy masses can be accomplished also by visco brakes (DE 39 09 231 A1). However, as far as can be seen, brakes of this kind have not yet been suggested for use as recoil brakes with rod strings adapted to be driven in rotation, especially not for rod strings in well bores.
It is common to all fluid brakes that their braking efficiency is dependent more or less upon temperature. That may become a problem when a fluid brake is used as recoil brake for a well bore rod string because drive heads of well bore rod strings often are employed at extreme temperatures and, in some places, at extremely great differences between day and night time temperatures. The temperature dependence of fluids such as normally used for fluid brakes thus may have the conse-quence that a fluid which is suitable for average temperatures or high temperatures, for example, will become so viscous at low temperatures that the recoil brake cannot provide suffi-cient dissipation of torsional energy stored in a well bore rod string to permit risk-free working at the drive head.
It is, therefore, the object of the invention to furnish a drive head for a rod string adapted to be driven in rotation, especially for driving a downhole pump, with a recoil brake at which it can be verified without any risk whether or not the torsional energy has been substantially dissipated.
The object is met, in accordance with the invention, by the features recited in claim 1. Advantageous further developments are the subject matter of the dependent claims.
Embodiments of the invention will be described in greater detail below, with reference to diagrammatic drawings, in which:
Fig. 1 is a vertical axial elevation of a drive head according to the invention;
Fig. 2 shows an enlarged cutout of fig. 1;
Fig. 3 shows a first modification of fig. 2;
Fig. 4 shows a second modification of fig. 2.
The drive head illustrated in fig. 1 serves to rotate a ver-tical rod string 10 extending from the surface of the ground down into a well bore and being connected at its bottom end to a pump rotor (not shown), for instance, a helical rotor of an eccentric worm type pump. The housing 12 encloses a gear cham-ber 14, a substantially horizontal partition 16 separating the gear chamber 14 from a seal chamber 18 located underneath it, and a locking gear and brake chamber 20 likewise located under the gear chamber 14 and separated from the seal chamber 18 beside it by a vertical partition 22. The housing 12 is formed with a lower passageway 24 and an upper passageway 26 ver-tically above it. The rod string 10 can be lowered and raised through these passageways. An oil aperture 28 provides con-stant communication between the gear chamber 14 and the locking gear and brake chamber 20 which are substantially filled with transmission oil. The seal chamber 18 contains a blocking fluid whose level can be monitored through a monitor-ing means (not shown), such as a sight glass or a sensor.
A sleeve 30 extends vertically from above through the upper passageway 26 down into the gear chamber 14 and further through the horizontal partition 16 into the seal chamber 18.
The sleeve 30 is supported in the partition 16 by a lower radial bearing 32 and immediately above it by an axial bearing 34. Moreover, it is supported in the upper passageway 26 of the housing 12 by means of an upper radial bearing 36. Above the housing 12, the sleeve is connected to the rod string 10 by a coupling 40 of conventional structure so as to transmit torque. The coupling 40 is releasable in order to permit raising or lowering of the rod string 10. A lower end portion of the sleeve 30 is enclosed by a cup-shaped insert 42 intro-duced into the housing 12 through the lower passageway 24, screw-connected to the housing, and sealed. The insert 42 is sealed with respect to the sleeve 30 by a lower slide ring seal 44 enclosed by the insert. An upper slide ring seal 46 is located spaced above the same and seals the sleeve 30 against the horizontal partition 16.
A gearing shaft 48 constituting part of a gear transmission 50 is disposed parallel to and spaced from the sleeve 30. It serves to transmit motion to the sleeve 30 and thus to the rod string 10 from a motor (not shown) arranged outside of the housing 12, for example an electric motor. The gearing shaft 48 is supported in the housing 12 by a lower bearing 52 and an upper bearing 54 and, between the two, it has a pinion 56 fastened to the shaft or, alternatively, formed integral with the same, as shown in the drawing, and constantly meshing with gear 38. The gearing shaft 48 includes a journal 58 extending downwardly beyond the lower bearing 52 and carrying a direc-tional locking gear 60.
The directional locking gear 60 comprises two bearings 62 arranged axially spaced apart on the journal 58 and an inner bushing 64 disposed between the two bearings for joint rota-tion with the journal 58. The inner bushing 64 is enclosed by an outer bushing 66 which is radially spaced from the inner bushing and supported on the two bearings 62. The two bushings 64 and 66 are coaxial with the gearing shaft 48 and define an annular space in which clamping rollers 68 responsive to the direction of rotation are housed. In the rotational operating direction of the gearing shaft 48 the directional locking gear 60 thus constituted acts as a freewheel device. On the other hand, it acts in blocking sense, driving a brake shaft 72 which belongs to a recoil brake 70 when the gearing shaft 48 is driven in opposite direction. The brake shaft 72 is flange-connected to the outer bushing 66 and carries a rotor 74 connected for joint rotation with the brake shaft 72 by means of a multi-groove profile, for example, the rotor being en-closed by a stator 76.
In the case of the drive head illustrated in figs. 1 and 2 the recoil brake 70 is a modified visco coupling such as normally used in the power train of four wheel drive motor vehicles. As shown, the modification may reside in no more than providing that part of a conventional visco coupling which serves as stator 76 in the coupling according to the invention with a flange 78 which is coaxial with the brake shaft 72. In the em-bodiment shown, the flange 78 is screw-connected to the stator 76. The flange 78 is responsible for centering the stator 76 in a bearing means 80 with respect to the brake shaft 72 and, upon release of a locking mechanism 82, it is held so as to be rotatable together with the brake shaft 72.
The locking mechanism 82 serves normally to firmly hold the stator 76 and prevent it from rotating, in other words to connect it rigidly to the housing 12, together with the bearing means 80. In all the embodiments shown, the locking mechanism 82 comprises a pawl 84 which is guided for radial displacement within the housing 12 and normally acts on or engages in a seat 86 associated with the stator 76. According to figs. 1 and 2 the seat 86 is a radial bore in the flange 78. Alternatively, the pawl 84 could be guided in a bore of the housing 12 parallel to the brake shaft 72 and thus engage in a paraxial bore or other seat 86 in the flange 78 or stator 76 itself.
In all the embodiments illustrated, the pawl 84 extends through the housing 12, having a head 88 at the outside thereof. A spring 90 is arranged between the housing 12 and the head 88, biasing the pawl 84 in outward direction in the sense of releasing the lock. Unintentional release of the locking mechanism 82 is excluded by any kind of suitable safety measure. In all the embodiments shown, a cover 92 shaped like a bow is provided for this purpose. It is fastened to the housing 12 by screws 94 and made tamper-proof by provi-sion of a lead seal 96. A switch 98 is fixed to the cover 97.
It will not release energy for supply to the motor (not shown) unless the pawl 84 and the cover 92 are in their normal posi-tions as illustrated, i.e. unless the locking mechanism 82 is effectively and verifiably secured.
With the locking mechanism 82 in this effective condition, torsional energy stored in the rod string 10 cannot be dissi-pated unless the rotor 74, propelled by the brake shaft 72, rotates with respect to the stator 76. This rotation can be rendered detectable from outside, e.g. by providing the housing 12 with a sight glass through which the rotor 74 can be observed.
When the torsional energy built up in the rod string 10 has been substantially dissipated and, consequently, rotation of the rotor 74 has stopped or dropped to a rotational speed no longer well noticeable, the cover 92 may be lifted off to examine, without any risk, whether perhaps a remainder of torsional energy worth mentioning still is stored in the rod string 10. After removal of the cover 92, if the bias of the spring 90 suffices to lift the pawl 84 off its seat 86, that is an indication that the torque acting on the stator 76, having come from the brake shaft 72 and through the rotor 74, has become so small that the corresponding tangential force transmitted from the seat 86 to the pawl 84 no longer can generate sufficient friction to hold the pawl 84 against the bias of the spring 90. On the other hand, if the locking mechanism 82 does not become released automatically once the cover 92 has been screwed off, this is an indication that per-haps a dangerous rest of torsional energy still may be contained in the rod string 10. That can be dissipated by enhancing the torque caused by the residual torsional energy by applying a screw driver to the gearing shaft 68 to turn the rotor 74 somewhat further than it already did itself with respect to the stator 76 which continues to be locked, turning the rotor against the shearing resistance of the fluid con-tained in the recoil brake 70.
The embodiment illustrated in fig. 3 essentially differs from the one according to figs. 1 and 2 in that the recoil brake 70 is a hydrodynamic brake. In this case the stator 76 is formed directly with the flange 78 for the bearing means 80 and the seat 86 for the pawl 84. While the visco brake shown in figs.
1 and 2, constituting the recoil brake 70, is provided in the usual manner with rotor fins 100 and stator fins 102 of the type which is conventional with visco brakes, the embodiment according to fig. 3 comprises rotor blades 104 and stator blades 106 of the structure which is usual with hydrodynamic retarders.
As regards the locking mechanism 82, fig. 4 does not differ from fig. 3. However, according to fig. 4 the rotor 74 is formed at regular angular spacings with a plurality of radial cylinders 108, for example six, each containing a piston 110.
Each piston 110 is biased radially outwardly by a spring 112 and is supported through a slide member 114 on an annular-oval race 116 which belongs to the stator 76. During each full rotation of the rotor 74, therefore, each piston 110 carries out a reciprocating motion. Next to the rotor 74 there is a control member 118 which is resiliently biased axially towards the rotor and secured against rotation on the stator 76.
A throttle 120 forming part of a hydraulic circuit is disposed radially outside of the control member 118. The hydraulic circuit further comprises an inlet passage 122 which leads from the locking gear and brake chamber 20 through the stator 76 and the control member 118 to the cylinder 108, and an out-let passage 124 which leads from the cylinder 108 through the control member 118 and the stator 76 to the throttle 120. The fluid being pumped passes through the throttle 120 and then flows into the locking gear and brake chamber 20. The oil aperture 28 permits constant exchange of fluid between the gear chamber 14 and the locking gear and brake chamber 20. As a result, the heat originating from the throttling is distri-buted in all of the fluid of which the major portion is con-tained in the gear chamber 14 in the embodiment illustrated, thus serving to lubricate the gear transmission 50.
In all the embodiments shown, the directional locking gear 60 and the recoil brake 70 are installed in the housing 12 from below through an opening subsequently closed by a cover 126.
An adapter 128 which is coaxial with the rod string 10 like-wise is connected via a flange to the bottom of the housing 12. This adapter carries the entire drive head and secures it against rotation.
List of reference numerals rod string 70 recoil brake 12 housing 72 brake shaft 14 gear chamber 74 rotor 16 partition 76 stator 18 seal chamber 78 flange brake chamber 80 bearing means 22 partition 82 locking mechanism 24 lower passageway 84 pawl 26 upper passageway 86 seat 28 oil aperture 88 head sleeve 90 spring 32 lower radial bearing 92 cover 34 axial bearing 94 screws 36 upper radial bearing 96 lead seal 38 98 switch coupling 100 rotor fins 42 cup-shaped insert 102 stator fins 44 lower slide ring seal 104 rotor blades 46 upper slide ring seal 106 stator blades 48 gearing shaft 108 radial cylinders gear transmission 110 piston 52 lower bearing 112 spring 54 upper bearing 114 slide member 56 pinion 116 race 58 journal 118 control member directional locking gear 120 throttle 62 bearing 122 inlet passage 64 inner sleeve 124 outlet passage 66 outer sleeve 126 cover 68 clamping rollers 128 adapter
Claims (6)
1. A drive head for a rod string (10) adapted to be driven in rotation, especially for driving a downhole pump, comprising - a housing (12) which has passageways (24, 26) for the rod string (10), - a sleeve (30) which is adapted to be driven in rotation and is supported in the housing (12), enclosing a section of the rod string (10), - a coupling (40) which connects the rod string (10) to the sleeve (30), and - a recoil brake (70) for controlled dissipation of torsional energy stored in the rod string, comprising a rotor (74) adapted to be driven by way of the sleeve (30) and a stator (76) which is supported by the housing (12), characterized in that the stator (76) is prevented from rotating with respect to the housing (12) by a locking mechanism (82) which can be released only when the rod string (10) is substantially free of torsional energy.
2. The drive head as claimed in claim 1, characterized in that the stator (76) is kept centered with respect to the housing (12) by a bearing means (80) which permits the stator to rotate substantially without resistance upon release of the locking mechanism (82).
3. The drive head as claimed in claim 1 or 2, characterized in that the locking mechanism (82) comprises a pawl (84) which is supported in the housing (12) and normally engages a seat (86) associated with the stator (76) by which seat the stator (76) exerts force on the pawl (84) to counteract the release of the lock as long as torsional energy is stored in the rod string (10).
4. The drive head as claimed in claim 3, characterized in that the pawl (84) is guided so as to be movable within the housing (12) and extends to the outside, being protected against withdrawal from outside by a cover (92) which is detachably fastened to the outside of the housing (12).
5. The drive head as claimed in claim 4, characterized in that the cover (92) carries a switch (98) which permits the rod string (10) to be driven by the motor only when the pawl (84) and the cover (92) are in their normal position.
6. The drive head as claimed in any one of claims 3 to 5, characterized in that the pawl (84) is biased by a spring (90) in the direction of disengaging the locking mechanism (82), the bias being sufficient to release the lock as soon as the torsional energy has been substantially dissipated.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19748907A DE19748907C1 (en) | 1997-11-05 | 1997-11-05 | Drive head for a rotationally drivable linkage, especially for driving a borehole pump |
| DE19748907.9 | 1997-11-05 | ||
| PCT/EP1998/006917 WO1999024717A1 (en) | 1997-11-05 | 1998-11-02 | Drive head for a rotary-driven rod assembly, especially for driving a sand pump |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2308164A1 true CA2308164A1 (en) | 1999-05-20 |
Family
ID=7847708
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002308164A Abandoned CA2308164A1 (en) | 1997-11-05 | 1998-11-02 | Drive head for a rotary-driven rod assembly, especially for driving a sand pump |
Country Status (8)
| Country | Link |
|---|---|
| EP (1) | EP1029178A1 (en) |
| CN (1) | CN1278317A (en) |
| AR (1) | AR010956A1 (en) |
| AU (1) | AU1337599A (en) |
| BR (1) | BR9813193A (en) |
| CA (1) | CA2308164A1 (en) |
| DE (2) | DE19748907C1 (en) |
| WO (1) | WO1999024717A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20130206523A1 (en) * | 2012-02-15 | 2013-08-15 | Ener Tools S.A. | Wellhead Drive Brake System |
| RU214071U1 (en) * | 2022-08-19 | 2022-10-11 | Общество с ограниченной ответственностью "РусОйлТехнолоджи" | INSTALLATION DRIVING THE ROD PUMP |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19849756C2 (en) * | 1998-10-28 | 2002-05-29 | Netzsch Mohnopumpen Gmbh | Drive head for a rotationally drivable linkage, in particular for driving a borehole pump |
| DE102010053901A1 (en) * | 2010-12-09 | 2012-06-14 | Netzsch Oilfield Products Gmbh | Modular torque protection |
| CN102747994A (en) * | 2012-07-18 | 2012-10-24 | 哈尔滨工业大学 | Liquid passing type electric-control layered polymer filling device |
| FR2997441B1 (en) * | 2012-10-29 | 2015-03-20 | Leroy Somer Moteurs | METHOD FOR EMPLOYING AN OIL WELL AND SYSTEM FOR ITS IMPLEMENTATION |
| CN106151052B (en) * | 2016-08-26 | 2018-12-28 | 韩全伟 | Surface drive with hydraulic, speed limit, temperature control reverse-rotation preventing function |
| CN106968643A (en) * | 2017-05-19 | 2017-07-21 | 大庆市晟威机械制造有限公司 | A kind of screw pump direct-driving device of utilization hydraulic braking polished rod |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3909231A1 (en) * | 1989-03-21 | 1990-09-27 | Ohb Opto Elektronik Hydraulik | Automatic-control viscous brake for quick, smooth braking of masses with high kinetic energy |
| GB2299849A (en) * | 1995-04-10 | 1996-10-16 | Mono Pumps Ltd | Downhole pump drive head assembly with hydrodynamic retarder |
| DE19616578C1 (en) * | 1996-04-25 | 1997-07-24 | Netzsch Mohnopumpen Gmbh | Drive head for rotary driven rod linkage for borehole pump |
| DE19628950C2 (en) * | 1996-07-18 | 1999-09-23 | Voith Turbo Beteiligungs Gmbh | Deep drilling device, deep drilling pump device and use of a hydrodynamic retarder to compensate for restoring moments triggered by the output in the drive system |
-
1997
- 1997-11-05 DE DE19748907A patent/DE19748907C1/en not_active Expired - Fee Related
-
1998
- 1998-11-02 DE DE19881676T patent/DE19881676D2/en not_active Ceased
- 1998-11-02 WO PCT/EP1998/006917 patent/WO1999024717A1/en not_active Ceased
- 1998-11-02 EP EP98956901A patent/EP1029178A1/en not_active Withdrawn
- 1998-11-02 BR BR9813193-1A patent/BR9813193A/en not_active Application Discontinuation
- 1998-11-02 CA CA002308164A patent/CA2308164A1/en not_active Abandoned
- 1998-11-02 CN CN98810800.3A patent/CN1278317A/en active Pending
- 1998-11-02 AU AU13375/99A patent/AU1337599A/en not_active Abandoned
- 1998-11-05 AR ARP980105573A patent/AR010956A1/en unknown
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20130206523A1 (en) * | 2012-02-15 | 2013-08-15 | Ener Tools S.A. | Wellhead Drive Brake System |
| RU214071U1 (en) * | 2022-08-19 | 2022-10-11 | Общество с ограниченной ответственностью "РусОйлТехнолоджи" | INSTALLATION DRIVING THE ROD PUMP |
Also Published As
| Publication number | Publication date |
|---|---|
| AR010956A1 (en) | 2000-07-12 |
| WO1999024717A1 (en) | 1999-05-20 |
| DE19748907C1 (en) | 1999-05-12 |
| BR9813193A (en) | 2000-08-29 |
| AU1337599A (en) | 1999-05-31 |
| CN1278317A (en) | 2000-12-27 |
| EP1029178A1 (en) | 2000-08-23 |
| DE19881676D2 (en) | 2001-03-22 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |