DE102008012676A1 - Rotary union - Google Patents

Abstract

A rotary leadthrough has a stator (12) and a rotor (14) mounted in the stator (12) by means of a rotationally symmetrical guide surface (30) and rotatable about an axis (16). The stator (12) has at least one first fluid line (52, 54, 62, 64, 90) and the rotor (14) at least one second fluid line (22, 24, 26), each in the guide surface (30) open and upon rotation of the rotor (14) in the stator (12) communicate with each other. Furthermore, at least one annular seal (66) is provided axially next to the orifice, in which an annular sealing body (86) arranged in the stator (12) or the rotor (14) bears against the rotor (14) or the stator (12) with a predetermined contact pressure ) is pressed. Means are provided for selectively pressing the sealing body (86) with at least two different contact pressures (FIG. 2).

Description

The The invention relates to a rotary feedthrough with a stator and one in the stator by means of a rotationally symmetrical guide surface mounted, about an axis rotatable rotor, wherein the stator at least a first fluid conduit and the rotor at least one second fluid conduit has, each open in the guide surface and during rotation of the rotor in the stator with each other and further wherein axially adjacent to the orifice at least a ring seal is provided, in which one in the stator or The rotor arranged, annular sealing body with a given contact pressure against the rotor or the stator is pressed.

The The invention further relates to a method for operating a rotary feedthrough.

The Finally, the invention relates to a use of a rotary feedthrough.

When a fluid under pressure is to be transferred to a device rotating relative to the unit in a housing-fixed unit, a rotary feedthrough is used. Rotary unions are well known, for example from the DE 40 19 987 C2 ,

at a typical application in the context of the present invention are boring bars in derricks when sinking a Bore successively screwed together to a longer and longer To form drill pipe. For the end screwing the Boring bars, an aggregate is used, which is to be screwed around the End of a first boring bar arranged around and is fixed in space. In the unit is a device that is fixed to the screwed end is connected and when screwing with this one turns. The rotary feedthrough serves to a Working fluid (or more), for example, 150 bar pressure as well a control fluid (or more) of lower pressure to the lift tool for the boring bars

The Screwing in takes place at a relatively low speed in the range between 15 and 25 rpm depending on the steepness of the respective thread. If the end to be screwed into the opposite end the next drill rod completely screwed is the pressure is removed, and the drilling process can continue become. The device remains on the drill rod, turns So with this idle with. When drilling becomes an essential set higher speed, for example, from 90 to 100 rpm.

at of these and many other applications, there is a problem that provided in the rotary feedthrough seals when in a working phase fluid under high pressure through the Rotary union flows, with high contact pressure must be operated to prevent the under high pressure fluid escapes. As long as the rotary feedthrough doing it at low speed and for limited periods of time running, this poses no problem. When the speed is increased in a subsequent idle phase, then there is an increased seal wear, even if no working pressure during the idling phase is present and the seal is pressed only by a bias. The seals heat up very much, for example to over 100 ° C, causing a chemical change and as a result it leads to a uselessness of the fluid.

There are also rotary feedthroughs known, for example from the already mentioned DE 40 19 987 C2 using a hydrostatic seal, for example a gap seal. Here there is no seal friction in the idling phase and in the working phase. In the working phase, however, the leakage rate of such seals is considerable.

Of the The invention is based on the object, a Rotary feedthrough, a use and a method of The aforementioned type in such a way that the above explained disadvantages are avoided. In particular, should in the working phase, the leakage rate of the rotary union low and in the idle phase, the seal friction may be low.

at a rotary feedthrough of the type mentioned is this object is achieved according to the invention by that means are provided to the sealing body optionally with at least two different contact pressures.

at a method of the type mentioned, the object is achieved according to the invention, that the rotary feedthrough with high contact pressure and smaller Circumferential speed of the guide surface operated when the fluid lines are at a working pressure Fluid are applied, and with low contact pressure and high Circumferential speed is operated when the fluid lines are depressurized are.

After all we solved the problem by using a rotary feedthrough the above-mentioned type for screwing boring bars of Derricks, for example for petroleum or natural gas wells, especially offshore.

The The object underlying the invention is complete in this way solved.

According to the invention namely the contact pressure of the seals in the rotary feedthrough set differently, namely high in the working phase and low in the idling phase. This will be in the work phase keeping the leak rate low and reducing seal wear during the idle phase, and the gaskets heat up only insignificantly. This does the inventive rotary feedthrough especially suitable for the application described above Screwing boring bars from derricks, for example of oil or gas wells, in particular in the offshore sector, generally speaking for all applications, in which worked with two different operations one of which is due to a low speed with Pressured channels and the other by a high Speed with pressure-free channels distinguishes.

at A preferred embodiment of the invention is a Contact pressure essentially equal to zero.

These Measure has the advantage that idle the wear and thus the heating of the seals to a minimum be reduced.

Prefers is the arranged in the stator sealing body at a contact pressure out of contact with the rotor or vice versa.

These Measure has the advantage that during the work phase the seal is fully pre-stressed and fully sealed with virtually no leakage. In the idle phase, however, the individual pressure-rotation seals not in contact with their respective mating surface.

Especially it is preferred if, in the frontal area between the stator and rotor further seals are provided.

These Measure has the advantage that the rotary feedthrough even then completely sealed to the outside, if the rotary pressure seals in the idle phase not in plant located on their respective mating surface.

at a practical realization of this embodiment the other seals are designed as shaft seals.

These Measure has the advantage that commercial Components can be used.

According to the invention more preferably, when the stator is movable relative to the stator Sealing bush, wherein the sealing body in the sealing bushing is arranged and the contact pressure in dependence of the position of the sealing bush varies relative to the stator.

These Measure has the advantage that the contact pressure by simple Moving the sealing bush can be changed.

This especially applies if the rotor in the guide surface provided with areas of different radial height is and the sealing body during a movement of the sealing bush over the areas will be moved.

These Measure has the advantage that the procedure of the sealing bushing and thus the change of the contact pressure by a simple mechanics can be effected.

at a preferred practical embodiment contains the at least first fluid line in the sealing bush a first Ring groove, wherein the sealing bush in the direction of the axis displaceable is and the areas as second annular grooves in the guide surface of the rotor are formed next to the first annular grooves.

These Measure has the advantage that the mechanical adjustment can be performed by a simple axial movement.

A Particularly good effect is achieved in this case, that the annular grooves have a rounded cross-sectional shape, and that preferably the sealing body with a tapered bearing side resting on the guide surface.

These Measure has the advantage that when moving the sealing bushing the sealing body continuous, d. H. without a jerky transition, is relaxed from his posture, in which he then preferably his respective counter-surface no longer touched. The contact pressure can be reduced to practically zero, when the tapered pad side is in the rounded Dips cross-sectional shape.

Especially is preferred in this embodiment further, when the sealing bush is hydraulically displaceable.

These Measure has the advantage that the displacement of the sealing bushing and thus remotely controlled the change in contact pressure and can be done quickly.

For this the sealing bush is preferably designed as an annular piston at the end, and the annular piston passes in a formed by the stator Ring cylinder.

This measure has the advantage that a compact size is created.

at Another embodiment of the invention is the Sealing bush tapped by means of one of the fluid lines Fluids hydraulically displaceable.

These Measure has the advantage that the need for separate Fluid lines for moving the sealing bushing eliminated.

at another embodiment opens next at least one ring seal a channel in the guide surface, and the channel is essentially depressurized.

These Measure has the advantage that shape changes kept low in the field of fluid lines and seals can be, in particular in the field of fluid lines, which serve as control lines.

there is preferred if the channel leads to a lateral pressure chamber, on the one hand by a shaft seal and the other by a ring seal is limited.

These Measure has the advantage that a possibly accumulating Pressure by moving the sealing bush is not on the Shaft seals can typically affect only one pressure withstand up to 5 bar.

at Embodiments of the invention Procedure is the small peripheral speed below 0.5 m / s, and the high contact pressure is between 100 and 200 bar, preferably about 150 bar, further preferably lies the high peripheral speed above 0.5 m / s, and the low In particular, contact pressure is less than 0.5 bar.

Further Advantages will be apparent from the description and the attached Drawing.

It it is understood that the above and the following yet to be explained features not only in each case specified combination, but also in other combinations or can be used in isolation, without the scope of the present To leave invention.

embodiments The invention are illustrated in the drawings and in the explained in more detail below description. It demonstrate:

1 a side view of an embodiment of a rotary feedthrough according to the invention;

2 a longitudinal section through the rotary feedthrough of 1 along the line II-II;

3 on a greatly enlarged scale a detail 2 in a work phase; and

4 a representation like 3 , but for an idle phase.

In 1 and 2 designated 10 as a whole a rotary union. The rotary feedthrough 10 has a stator 12 and one in the stator 12 rotatable rotor 14 on. The axis of rotation of the rotor 14 is with 16 and the rotation is with an arrow 18 indicated. The stator 12 and the rotor 14 both preferably have substantially the shape of a hollow cylinder, as can be clearly seen 2 recognizes. The longitudinal axis of the hollow cylinder coincides with the axis of rotation 18 together.

In a practical embodiment for the Use according to the invention in the offshore sector the rotary union is about 600 mm long and has a Diameter of about 420 mm. It is understood, however, that this is just one of many possible examples.

The rotor 14 has a first sleeve 20 on. In the first sleeve 20 extend axial channels, of which in 2 one at 22 is shown. From the inner end of the axial channel 22 goes a radial channel 24 from on an outer surface of the first sleeve 22 empties. The outer end of the axial channel 22 ends in a connection 26 in an in 2 left front side 28 of the rotor 14 ,

It is understood that a variety of such channels 22 . 24 . 26 or lines over the circumference of the first sleeve 20 or the front side 28 may be distributed, for example, seven or nine such channels. A distinction is made between working channels and control channels. Work channels usually have a larger cross-section and conduct a working fluid, which is needed for example for actuating piston-cylinder units. Control lines, on the other hand, usually have a smaller cross-section and conduct a fluid which is needed for actuating control elements, in particular valves.

On an outer peripheral surface 30 of the rotor 14 , at the same time as a guide surface between stator 12 and rotor 14 serves, are end bearings 32a and 32b arranged the rotor 14 rotatable in the stator 12 to store. Camps 32a and 32b are in 2 only schematically drawn because this type of storage is known in the art.

The stator 12 has a second sleeve 40 on, coaxial with the first sleeve 20 is arranged. The second sleeve 40 is with a window 42 Mistake.

Between the second sleeve 40 and the first sleeve 20 there is a sealing bush 50 , The sealing bush 50 is between the pods 20 and 40 mounted axially displaceable, as with a double arrow 51 indicated. In the direction of rotation 18 but she is with the stator 12 connected so that they are part of the stator 12 forms. The sealing bush 50 is provided with a plurality of terminals, namely with working ports 52 and with control connections 54 belonging to the above-mentioned working or control channels. The connections 52 and 54 are through the window 42 accessible, with the window 42 is dimensioned so that this accessibility over the full displacement (arrow 51 ) of the sealing bush 50 preserved. The to the connections 52 and 54 connected from the outside fluid lines are formed at least over a certain length as flexible hose lines to the displacement of the sealing bushing 50 to be able to follow.

Between the sealing bush 50 and the camps 32a and 32b are located in 2 left pressure chamber 58 as well as a right pressure room 60 , By introducing a fluid into one of the two pressure chambers 58 respectively. 60 can the sealing bush 50 in the direction of the arrow 51 be moved axially. The required for the displacement fluid pressure in the pressure chambers 58 respectively. 60 may conveniently be provided by tapping the working or control pressure in one of the working or control channels (not shown). This can for example be effected by the fact that the pressure chambers 58 respectively. 60 be subjected to pressure earlier than a tapped annular groove 62 or 64 , Then there is the sealing bush 50 already in the desired end position, if on the corresponding other connections 52 respectively. 54 Pressure is given.

On the inner peripheral surface of the sealing bush 50 are first ring grooves 62 as working channels and second annular grooves 64 designed as control channels. The first ring grooves 62 stand outside the plane of the drawing 2 with the work connections 62 , and the second ring grooves 64 stand with the control terminals 54 in connection.

On both sides of the ring grooves 62 and 64 are located in the inner peripheral surface of the sealing bushing 50 still ring seals 66 of which in 2 for clarity, only four next to the second annular grooves 64 are shown.

In the frontal area of the rotary feedthrough 10 are at the camp 32a . 32b even more seals 68a . 68b provided, which are preferably formed as shaft seals. The other seals 68a . 68b are designed for the high speeds of the leelaufphase and are designed for example for an operating pressure of 5 bar maximum.

Furthermore, in the sealing bushing 50 radial pressure relief lines 70 provided between the ring seals 66 in the inner peripheral surface of the sealing bush 50 lead. In the 2 the leftmost pressure relief line has an axial branch 72 leading to a pressure relief cavity 73 leads. The cavity 73 is located between the in 2 left bearing 32a and the adjacent thereto radial end face of the sealing bushing 50 ,

The pressure relief lines 70 lead to a common, axial manifold 78 , This is in turn to a connection 80 connected, which also through the window 42 is accessible from the outside. The connection 80 is connected to a pressureless fluid tank. That's why it's out of the pipes 70 . 72 . 78 formed line system is depressurized or is at a very low pressure level of less than 0.5 bar.

The pressure relief lines 70 are in particular between those to the tax terminals 54 belonging ring grooves 64 arranged. The channels 70 ensure that, for example, an increase in pressure in an annular groove 64 the ring seal 66 deformed, but this the adjacent ring groove 64 not influenced in such a way that by a change in volume, the pressure in the adjacent annular groove 64 changed because of the channel 70 depressurized and connected to a tank.

The turnoff 72 connects the pressure relief lines to the cavity 73 , on the one hand by the further seal 68a and in the working phase through the ring seal 66 is limited. This has the consequence that a possibly accumulating pressure by moving the sealing bushing 50 do not care about the further seal 68a which, as mentioned, can only withstand a lower operating pressure.

In the 3 and 4 are details of the ring seals of the invention 66 shown.

The ring seals 66 become by third, rectangular ring grooves 82 formed, in the bottom of which an elastic O-ring 84 is inserted. On the O-ring 84 is an annular, largely inelastic sealing body 86 hung up. The sealing body is on its inner circumference with a support side 88 provided, which is preferably formed tapered. Such ring seals are known in the art.

3 shows a working state of rotation implementation, in which the working channels are pressurized, for example, with 150 bar operating pressure, and in which the rotor 14 in the stator 12 rotates at low peripheral speed v of the outer peripheral surface of less than 0.5 m / s. In rotary unions of conventional size, as exemplified above, this corresponds to a speed range of, for example, 15 to 25 U / min.

4 shows an idle state of the rotary feedthrough in which the working channels are substantially depressurized and in which the rotor 14 in the stator 12 with high peripheral speed v of the outer circumferential surface 30 of more than 0.5 m / s rotates, which corresponds to a speed range of, for example, 90 to 100 U / min in the said size.

In working condition of 3 is the rotary feedthrough 50 axially preferably positioned so that the first annular grooves 62 with the radial channels 24 essentially aligned. The working fluid can now freely from the working ports 52 in the stator 12 to the axial channels 22 and the connections 26 in the rotor 14 flow like arrows 92 indicated.

In this working condition are the edition pages 88 the ring seals 66 on the cylindrical outer peripheral surface 30 of the rotor 14 on. The depth and width of the third ring grooves 82 are dimensioned such that the O-rings 84 be radially compressed in this state, so that a high contact pressure of the bearing sides 88 on the outer peripheral surface 30 arises and thus a high sealing effect or a low leakage rate in particular between the annular grooves 62 is effected.

In this state, the high fluid pressure acted upon first and second annular grooves 62 . 64 affects the pressure relief through the pressure relief lines 70 between the ring seals 66 out. The pressure relief bends, as mentioned, in particular an influence on the control annular grooves 64 with each other by changing the behavior of a ring seal 66 to the next ring seal 66 due to deformation of the latter, because the adjacent ring seals 66 through one of the unpressurized pressure relief lines 70 are separated from each other.

In the outer peripheral surface 30 are now in the field of ring seals 66 Fourth ring grooves 94 introduced, which preferably have a rounded at the bottom axial profile. These fourth annular grooves are in the in 3 shown working state inactive. The ring grooves 94 are designed so that they have a non-preloaded ring seal 66 can absorb, with the ring seal 66 preferably in a working position by an axial end position of the sealing bushing 50 is determined, their mating surface in the outer peripheral surface 30 not touched.

When changing from the working state to the idling state, the sealing bushing shifts 50 in the in 4 shown position. In this position are the work connection 52 and the first ring groove 62 axially by an amount Δz with respect to the radial channel 24 added. The sealing body 86 can now due to the rounded shape of the fourth annular grooves 94 steadily slide into it.

In this neutral position, the fourth annular grooves are aligned 94 with the ring seals 66 , This causes the sealing body 86 with their overlay side 88 in the fourth ring grooves 94 occurred. This will relax the O-rings of 84 ( 3 ) to 84 ' ( 4 ). The contact pressure of the ring seals 66 As a result, it is considerably reduced and can even drop to zero. It is particularly preferred if the sealing body 86 in idle position no contact with the rotor 14 have, as in 4 shown.

It it is understood that the invention by the above description an embodiment is not limited. In particular, the invention also encompasses exemplary embodiments, in which each of the elements explained in kinematic Inversion instead of on the stator are arranged on the rotor and vice versa.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 4019987 C2 [0004, 0008]

Claims (18)

Rotary feedthrough with a stator ( 12 ) and one in the stator ( 12 ) by means of a rotationally symmetrical guide surface ( 30 ) stored around an axis ( 16 ) rotatable rotor ( 14 ), wherein the stator ( 12 ) at least one first fluid line ( 52 . 54 . 62 . 64 . 90 ) and the rotor ( 14 ) at least one second fluid line ( 22 . 24 . 26 ), each in the guide surface ( 30 ) and upon rotation of the rotor ( 14 ) in the stator ( 12 ) and further wherein axially adjacent to the orifice at least one annular seal ( 66 ) is provided, in which a in the stator ( 12 ) or the rotor ( 14 ) arranged, annular sealing body ( 86 ) with a predetermined contact pressure against the rotor ( 14 ) or the stator ( 12 ) is pressed, characterized in that means are provided to the sealing body ( 86 ) optionally with at least two different contact pressures. Rotary feedthrough according to claim 1, characterized that a contact pressure is substantially equal to zero. Rotary feedthrough according to claim 1 or 2, characterized in that in the stator ( 12 ) arranged sealing body ( 86 ) at a contact pressure out of contact with the rotor ( 14 ) or vice versa. Rotary feedthrough according to one or more of claims 1 to 3, characterized in that in the frontal region between the stator ( 12 ) and rotor ( 14 ) further seals ( 68a . 68b ) are provided. Rotary feedthrough according to claim 4, characterized in that the further seals ( 68a . 68b ) are formed as shaft seals. Rotary feedthrough according to one or more of claims 1 to 5, characterized in that the stator ( 12 ) one relative to the stator ( 12 ) movable sealing bush ( 50 ), that the sealing body ( 86 ) in the sealing bush ( 50 ) is arranged and that the contact pressure in dependence on the position of the sealing bush ( 50 ) relative to the stator ( 12 ) varies. Rotary feedthrough according to claim 6, characterized in that the rotor ( 14 ) in the guide surface ( 30 ) is provided with regions of different radial height and that the sealing body ( 86 ) during a movement of the sealing bush ( 50 ) is moved over the areas. Rotary feedthrough according to claim 7, characterized in that the at least first fluid line ( 52 . 54 . 62 . 64 . 90 ) in the sealing bush ( 50 ) a first annular groove ( 62 . 64 ) contains that the sealing bushing ( 50 ) in the direction of the axis ( 16 ) is displaceable and that the areas as second annular grooves ( 94 ) in the guide surface ( 30 ) of the rotor ( 14 ) next to the first annular grooves ( 62 . 64 ) are formed. Rotary feedthrough according to claim 8, characterized in that the annular grooves ( 94 ) have a rounded cross-sectional shape, and that preferably the sealing body ( 86 ) with a tapered bearing side ( 88 ) rests on the guide surface. Rotary feedthrough according to claim 8 or 9, characterized in that the sealing bush ( 50 ) is hydraulically displaceable. Rotary feedthrough according to claim 10, characterized in that the sealing bush ( 50 ) is designed as an annular piston end and that the annular piston in a through the stator ( 12 ) formed ring cylinder is running. Rotary feedthrough according to claim 10 or 11, characterized in that the sealing bush ( 50 ) by means of one of the fluid lines ( 52 . 54 . 62 . 64 . 90 ) bled fluid is hydraulically displaceable. Rotary feedthrough according to one or more of claims 8 to 12, characterized in that in addition to at least one annular seal ( 66 ) a channel ( 70 ) in the guide surface ( 30 ) and that the channel ( 70 ) is substantially depressurized. Rotary feedthrough according to claim 13, characterized in that the channel ( 70 ) to a lateral pressure chamber ( 73 ), on the one hand by a shaft seal ( 68a . 68b ) and on the other hand by a ring seal ( 66 ) is limited. Method for operating a rotary feedthrough ( 10 ) according to one or more of claims 1 to 13, characterized in that the rotary feedthrough ( 10 ) with high contact pressure and small peripheral speed (v) of the guide surface ( 30 ) is operated when the fluid lines ( 52 . 54 . 62 . 64 . 90 ; 22 . 24 . 26 ) are acted upon by a fluid under working pressure, and with low contact pressure and high peripheral speed (v) is operated when the fluid lines ( 52 . 54 . 62 . 64 . 90 ; 22 . 24 . 26 ) are depressurized. Method according to claim 15, characterized in that that the small peripheral speed (v) is less than 0.5 m / s and the high contact pressure between 100 and 200 bar, preferably about 150 bar. The method of claim 15 or 16, since characterized in that the high peripheral speed (v) is more than 0.5 m / s and the low contact pressure is less than 0.5 bar. Use of a rotary feedthrough ( 10 ) according to one or more of claims 1 to 14 for screwing drill rods of derricks, for example, for oil or gas wells, especially in the offshore area.