Mechanical seal Yor sealing at least one fuid-conducting channel andior space The present invention relates to a mechanical seal for saaling at least one fluids conducting channel andfor space extending in a stationary component and/or a rotating component with respect to the environment, according to the preamble of claim 1. A mechanical seal of this type is known from DE 34 26 539 AT.
The mechanical ssa! has a rotating siiding ring around an axis of rotation, the face of which is supported on a mating ring in the axial direction, Le. in the direction of the axis of rotation.
The end face thus forms the sealing surface.
The sliding ring Is subject to wear due to is relative rotation and elastic support against the mating ring.
Due to wear, the sliding ring moves increasingly in the axial direction.
To ensure that the sliding ning can be replaced in good time before it is too worn and thus loses ds sealing effect, the wear is detected by providing a probe radially io the axially movable sliding ring, which detects how far the sliding ring has already moved axially relative to the probe.
For this purpose, a magnetic insert can be provided in the sliding ring orin a component that moves with the sliding ring, and the probe can be designed as an electromagnetic sensor that detects a signal from the magnetic insert, wherein the signal reaches a meximum when the wear surfaces have reached maximum wear, in the mechanical seal shown, the probe is positionad away from the rotating siding ring ina stationary housing and is screwed, for sxampie, radially from the outside into a radial bore in the housing.
The housing carries a replaceable seat that forms a stationary mating ring for the seal face of the mechanical seal The sliding ring itself is adally movable and rolatably positioned on a shaft and is enclosed in the axial direction between the seat and a secondary seal enclosing the shaft, wherein the secondary seal is produced by a pressure bellows which at the same time presses the sliding ring in the axial direction against the mating ring. — Since the sliding ring rotates relative to the mating ring and thus the housing, K must be ensured that the signal from the magnetic insert can be reliably detected oy the probe at any possible speed.
A further, even more serious disadvantage of the embodiment shown is thal in the event of leakage between the end sealing surface of the mechanical seal and the mating ning, tor example due to an unevenness or subsequently introduced damage in the sealing surface of the mechanical seal, complete disassembly of the entire mechanical seal is necessary in order to be able jo machine the face flat.
Subsequently, the various elemenis of the mechanical seal must be realigned during reassembly.
US 2017/045144 AT discloses a dry gas seal used in gas compressors in the oi and gas industry.
This saal is operated in such a way that a dynamic gas film is established between the rotating sealing surface and the stationary sealing surface.
For this purpose, a gap must be maintained between the two sealing suracss.
ER 3 3/6 079 AJ also discloses a dry gas seal in which a gap must be set — between the sealing surfaces.
Another gas seal in which the sealing surfaces do not touch is disclosed in US 2000/290971 AT.
The present invention is based on the object of providing a mechanical seal for sealing a channel and/or space ekiending in a sigtionary and/or in a rotating component and carrying a fluid, such as guld or gas, in which machining or re- machining of the sealing surface of the mechanical seal is more easily possible.
The mechanical seal is preferably further characterized Dy more reliable wear detection regardiess of the rotational speed of the rotating component.
A mechanical seal according to the invention for sealing at least one fluids conducting channel andfor space extending in a stationary component and/or a rotating component with respect jo the environment has a siding ring which is supported in a sealing manner in the axial direction against a mating ring. in ons embodiment of the invention, the at least one iuid-sondustino channel extends from a stationary component into a rotating component or from a rotating component info the stationary component, thus through a rotary union.
The rotary union serves io transfer the fluid from the respective channel section of the stationary component into the respective channel section of ins rotating component, is. the component rotating about an aus of rotation, or vice versa.
However, the invention can also be applied independently of a rotary union in any component in which sealing by a mechanical seal is used. in this respect, the channel conducting the fluid is any space in a stationary component and/or in a rotating component which is sealed off from an environment by the mechanical sea! The environment may be another space in the component and/or another component, or an environment that is no longer enclosed by housing parts.
The environment may bs unpressunized or pressurized.
The Hud may flow or be stationary in the channel and/or space.
By way of example only, reference is
—madetotihe sealing of at least one channel and/or space conducting a fluid in a pump, such as a liquid pump or gas pump, a compressor and other working machines.
Since the sliding ring is supported in the axial direction, Le. in the direction of the axis of rotation of the rotating component, against the mating ring in a sealing manner Lis subject to wear For example, the sliding ring is made of a carbon or comprises such carbon. in order io prevent the wear, which shortens the sliding ring in the axial direction, from causing a isak, for example in the rotary union, the sliding ring js movable in the axial direction and, to compensate for the wear, is slastically supported against the mating ring by iis end sealing surface.
Progressive wear is thus compensated for by increasing axial displacement of the shding ring in the direction of the mating ring.
In addition or aliernatively, the mating ring can also be subject to abrasion or wear in the area of a mating surface in contact with the sealing surface of the sliding ring, so that axial displacement of the sliding ring by its elastic pretension takes place to compensate for this.
inorder to be able fo evaluate the extent of wear or the axiai movement of the sliding ring that has already taken place, a position sensor is provided to detect the position of the sliding ring in the axial direction.
According to the invention, the position sensor comprises ai least one transducer fixed to the sliding ring or supported against the shiding ring in the axial direction and moving with the sliding ring in the axial direction, as well as a stationary sensor positioned radially outside the sliding ring, which delscts the position of the transducer in the axial direction.
The at least one transducer, in particular in the form of a magnet, can for example De introduced mio a bore, in particular a radial bore, of the sliding ning.
According to the invention, the stationary sensor is connected to and/or supported by a housing that movably accommodates the sliding ring in the axial direction.
The end sealing surface of the sliding ring proirudes in the axiai direction relative to this housing, Le. the end sealing surface of the sliding ring is positioned in the axial direction outside the housing and at a distance from the housing, so that machining, in particular surface machining, of the end sealing surface js possible when the shding ring is mounted in the housing.
in particular, the sealing surface can be lapped.
During such lapping, the ssaling surface of the sliding ning can be placed on the lapping machine in order to make the sealing surface particularly Hai The slicing ring can be mounted in the NOUSING.
According to ong embodiment of the mention, the sialionary sensor is detachably connected io the housing, for example by means of a snap-in connection.
In this case, the stationary sensor can be removed from the housing, if necessary, before the sealing surface is machined flat, in ons embodiment of the invention, the siding ring also projects with is end sealing surface in the axial direction relative to the stationary sensor. in this case,
machining of the sealing surface, for examples by lapping, is possible even fd the stationary sensor is non-detachabiy connected to the housing.
According io one embodiment of the invention, the sliding ring is stationary and the mating ring rotates relative to the sliding ring.
Stationary in this case means that the sliding ring can only move in the axial direction, but not in the circumferential direction, or at least is not driven in the creumfsrential direction. in this case, a particularly reliable signal coupling between the ransducer and the stationary sensor is ensured, regardiess of the speed of the rotating component, The transducer may, for example, comprise ai least one magnet or be formed by at least one magnet, and the stationary sensor may be designed as a Hall sensor that detects the position of the at least ong magnet in the axial direction. in particular, such a Hall sensor has an electric current flowing through i and generates an output voltage that is proportional to the product of the current and a magnetic flux density generated by the magnet associated with the sliding ring.
Particularly advantageously, the sliding ring is elastically supported against the 5 housing for its support against the maling ring.
For example, the housing encloses the sliding ring in the circumferential direction and has a housing base which is opposite an end face of the sliding ning facing away from the sealing surface.
The sliding ring can then be slastically supported on the housing base Dy means of a spring element, for example Dy means of a wave spring or another compression spring positioned between the end face and the housing base,
For example, the siding ring comprises or is formed from a hollow oylindricai carbon ring having an end face forming the sealing surface.
Preferably, the carbon ring further has said end face facing the bottom of the housing.
The carbon ring then protrudes from the housing in the axial direction
According io a particularly advantageous embodiment of the invention, the housing surrounds the sliding ring in the circumferential direction and has a radially inwardly directed projection.
The sliding ring has a stop face opposite the radially inwardly directed projection in the axial direction, with which the sliding ring abuts against the projection during a maximum permissible movement in the
— axial direction.
This prevents the sliding ring from being pressed completely out of the housing.
Preferably, the transducer, in particular the at least ons magnet, Or an intermediate component carving the ransducer, in particular the at least one magnet, is supported against this stop face or resis on this stop face to align the magnet or the component.
The housing can have an opening in the radial direction through which the intermediate component or the transducer, in particular the at least one magnet of the transducer, projects radially outwards from the housing.
The sliding ring can be saaled against the housing by means of a sealing element, for example an O-ring, especially in the radial direction.
The housing can be made of steel or sheet steel, for example,
in particular, the position sensor is designed in such a way that i not only detects the end positions of a sliding ring that is not yet wom and a sliding ring that is completely worn, but also intermediate positions existing between these end positions. In particular, a continuous movement of the sliding ring in the axial direction is detected in each position. in one embodiment of the siding ring with a stop face facing in the axial direction, which pravents the sliding ring from being pushed complataly out of the housing, the end face with the sealing surface protrudes in the axial direction relative to the stop face. The stop face can preferably be provided radially outside or radially — inside the sealing surface. The intermediate component can be provided, for example, in the form of a slide supported on the stop face, which is pressed elastically against the stop face and is held in parliottiarin s slide rad on the housing. Although in the foregoing and following exemplary embodiments of the invention the ring moving in the axial direction to compensate for its wear has been referred to as a sliding ring and the comparatively harder ring, which in particular does not wear or wears less, has been referred to as a mating ring, the present invention also includes embodimenfs in which not or noi only the ring moving in the axial direction wears on the face side, but also such embodiments in which a ning stationary in the axial direction is designed to be equality soft or softer than the ring movable in the axial direction and thus wears on its end face in addition to the ring movable in the axial direction or instead of the ring movable in the axial direction, The inveniion will be described below by way of example by means of an exemplary embodiment and the figures, wherein: Fig, 1 shows a three~-dimensional plan view of a mechanical seal designed according to the invention; Fay & shows an axiai section through the mechanical seal of Fig. 1;
Fig. 3 shows an enlargement of the area with the position sensor;
Fig. 4 shows a representation similar to Fig. 3, but with magnets mounted directly in the sliding ring;
Fig. 5 shows a schematic representation of a detachable connection of the sensor to the housing by means of a snap-in connection. Fig 1 shows an exemplary embodiment of a mechanical seal according to the invention for sealing a rotary union, havina a channel 1 that conducts a fluid from a stationary component into a rotating component. The stationary component is, for example, schematically indicated in Fig. 2 and numbered 2, and the rolating component is also schematically indicated in Fig, 2 and numbered 3. As can be seen from Figs. 1105, the mechanical seal has a siiding ring 4 which has a seaiing surface 5 on an axial end face, with the sealing surface 5 being supported on a mating surface 6 of the rotating component 3 in order fo seal off the channel i from the surroundings or a leakage side 7. The sliding ring 4 is made of a wear-resistant material in the area of its sealing — surface 5 andfor the rotating component 3 is made of a wear-resistant material in the area of the mating surface 6, wherein the wear is caused by abrasion of the material during the relative rotation between the sliding ring 4 or the sealing surface 5 and the malting surface 6. in order to nevertheless achieve the desired sealing in the area of the sealing surface 5 or mating surface §, the sliding ring 4 — is elastically supported in a housing 9 at is axial end facing away from the sealing surface 5 by means of a spring element, in this case a compression swing or wave spring 8. As can be seen from Figs. 2, 4 and 5, the support by means of the compression spring or wave spring is provided, for example, on a housing base 22 of the housing 9. The channel 1 extends in the axial direction through the housing 9 and the sliding ring 4 and preferably also through the wave spring 8 An O-ring 10 is provided between the sliding ring 4 and the housing 9 for sealing. The sliding ring 4 has a shoulder or stop face 11 which, when the sliding ning 4 extends in the axial direction out of the housing 9, strikes a radially inward projection 12 of the housing 9 to prevent further extension of the sliding ring 4 out of the housing 9. A stationary sensor 13 is connected to the housing 9, which is positioned radially outside to a magnet 14 and is designed as a Hall sensor that detecis an axial position of the magnet 14 and thus of the sliding ning 4 The magnet 14 is connected in particular directly to the siding ring 4, see Fig 4, or via an intermediate component 15 which moves in the axial direction together with the sliding ring 4 and carries the magnet 14, ses Figs. 1103. Preferably, the magnet 14 or the intermediate component 15 is supported in the axial direction on the stop face 11. in the exemplary embodiment shown in Figs. 1 to 3, the intermediate component is elastically supported agamst the stop face 11 by means of a spring element
16. Alternatively, a rigid connection of the intermediate component 15 to the sliding ring 4 could also be considered. in the exemplary embodiment shown in Fig. 4, one magnet 14 exdending in the 15 circumferential direction over the entire circumference of the sliding ing 4 is provided or several magnets 14 are arranged distributed over the oiroumfersnoe of the sliding ring 4 in order to allow rotation of the sliding ring 4 relative to the stationary sensor 13 without impairing the functioning of the position detection. However, this is not mandatory. The stationary sensor 13 has a sensor housing 18 in which a temperature sensor 1918 integrated. The temperature sensor 19 delecis the temperature of a isakage flow of the fluid guided in the channel i that passes from the channel 1 over the sealing surface 5, wherein the detected temperature is dependent on the size of the leakage flow because the arrangement of the temperature sensor 18 or of the stationary sensor 13 in the leakages flow noreases the heat transfer between the leakage flow and the stationary sensor 13 or temperature sensor 19 ss the leakage flow noreases. The stationary sensor 19 further forms, together with the magnet 14, a position sensor 20 for detecting the position of the sliding ring 4 in the axial direction.
The position sensor 20 is designed as a Hall sensor and the temperature sensor 19 is further used io compensate for the temperature dependence of the measured variable detected by the Hall sensor.
For this purpose, a control device 21 can be provided in the sensor housing 18 or outside of if, which controls the position detection and in particular the leakage currant detection. in order to be able fo plane the sealing surface 5, the stalionary sensor 13 is preferably detachably connected to the housing 9, for example Dy means of a snap-in connection.
The snap-in connection is not shown in detail in the illustrations in Figs. 110 3 in Fig. 5, the snap-in connection is numbered 23. This snap-in connection 23 comprises at least one snap-in opening in the housing 9 and at least one snap-in lug in a carrier carrying at least the stationary sensor.
Additionally or altematively, the at least one snap-in opening may also be provided in the carrier and the at least one snap-in lug may De provided in the housing. i as shown in Fig. 5, further components associated with the position — sensor 20 are also provided protruding in the axial direction beyond the sealing surface 5 of the sliding ring 4, these are also supported in the camer 24, for example, his is provided, the spring element 16 ano/or the intermediate component 15. All components protruding in the axial direction beyond the sealing surface 5 can be removed from the housing 9 together with the carrier 24 — to enable the desired machining of the sealng surface 5. In principle, several removable supports could also be provided for the various components, and/or one Or more components could De directly removably connected jo the housing.
Alternatively, all components associated with the position sensor 20 ars arranged behind the sealing surface & in the axial direction 4, so that the sealing surface 5 projects beyond the housing 9 and the position sensor 20 in the axial direction, This is shown, for example, in Fig. 4. in this case, it is not necessary jo detachably connect the position sensor 20 or components thereof, such as the stationary sensor 13, to the housing 9, because the machining of the sealing surface 5, even Dy lapping, is not impeded. ir the case of a detachable connection as shown in Fug 1, which is not shown in more detail, it is possible jo remove the siationary sensor 13 from the housing 9, in particular together with the intermediate component 15 and the sliding rail 17 which holds the intermediate component 15 in a displaceable manner.
Subsequently, the sealing surface 5 can be lapped, for example. in an embodiment with intermediate component 15, the housing 9 advantageously has an opening in the radial direction, for example in the form of anoteh, through which the intermediate component 15 engages radially from the — outside in order to be supported on the stop face 11 or in order to be able to fasten the intermediate component 15 more easily io the sliding ring 4, in particular rigidly.
List of reference signs 1 Channa 2 Stationary component 3 Rotating component 4 Sliding ring 5 Sealing surface 8 Mating surface 7 Leakage side 8 Wave spring 9 Housing io O-ring ii Stop face 12 Projection 13 stationary sensor 14 Magnet 15 intermediate component 16 Spring element 17 Sliding rail 18 Sensor housing 19 temperature sensor 20 Position sensor 21 Control device 22 Housing base 23 Snap-in connection 24 Carrier