FR2531514A1 - HYDRAULIC JOINT - Google Patents

Abstract

THIS GASKET IS OF THE TYPE INCLUDING A RECESSED 3, ORIENTS INWARDS IN THE RADIAL DIRECTION AND BOUNDARED BY AN UPSTREAM COLLAR 4 AND A DOWNSTREAM COLLAR 5 LOCATED ON PART 2 WHICH RUNS AT THE GREATEST SPEED, A DEVICE 7 PROVIDING A LIQUID UP TO RECESS 3, A SEALING FIN 6, LOCATED ON THE OTHER ROTATING PART 1 AND PROJECTING FAR ENOUGH INSIDE RECESS 3 TO ENTER THE LIQUID HELD IN THE RECESSED BY CENTRIFUGAL FORCE. IT INCLUDES, IN ADDITION, A PUMP ROTATING WITH THE PART WHICH TURNS AT THE GREATEST SPEED AND MOUNTED SO AS TO RECEIVE THE LIQUID FROM THE FEEDING DEVICE 7 OR FROM THE RECESSED 3 TO DRIVE THIS LIQUID AT THE SAME SPEED AS THE PART 2 AND SEND IT IN RECESS 3, IN THE ZONE WHICH IS LUS NEAR THE OUTSIDE IN THE RADIAL DIRECTION.

Description

Hydraulic seal

  The present invention relates to a hydraulic seal.

  Hydraulic seals are known which connect two pieces which are rotatable relative to the ur and which provide a first rotary part in which a radially inwardly oriented recess and a second rotary part are provided. rotating in the n 2 ema, direction, but at a lower speed, and having an alet-te of étonchéité -projected inside the ren -iofenemo U e renfo ncement is delimited by a collar E, amee and a downstream collar and is filled with liquid The

  Aiide is Maintonu is placed by centrifugal force and

  2 you think of it in your own way as a result of the recessing and forging at 5 merz an all-wise shredder of throttle guns at the end of the day; If the downstream glue Zcec-ed ass ZGF law L in the radial zemus, goose 7 can make the centrifugation drill which is carried out on the ground. and the flange downstream is greater than five inches, so that it exerts an additional amount of air, which has the effect of reducing the amount of oil required. opposed to the passage of gas at the nr of the airtight vane The force which produces the rotation of the liner in the recess results from the friction which, at a distance between L, the liquid and the walls of the wall or ceiling. There is, therefore, a factor that causes all the liquid to reach its humeral mouth, which has effectively and provoke

  The pressure of centrifugation presses the liquid.

  The seals of this type are therefore used satisfactorily only with small flanges and when the gas pressure is relatively low (35) 455 to 790.degree. Pa for example O Moreover leujr use is limited to the case where the two parts

  constituting the joint rotate in the same direction.

253151 4

  When the pressure of gas is much higher, of the order of 426 473 to 569-306 Pa for example, it was necessary to

  Centrifugal forces in the relationship are much more important.

  rable, which leads to the collar downstream a beautiful

  Big height in 2 directions Gold, for

p-P t OUJOUI-2-0 Possible to use

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-_er on-finces den ci-

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to crisis ide dm 1 (s-

  In this case, the effect is that of the daughter of the child who is pregnant with the child, and the child is the child of the child. O, N o l l l l l l l l l l l l l l l l

This goal is attainted, 11-Ritiliza-

  L) dlum 'to -hydraulic turn (Dr 1-moon by rae or' to llau'Z G -, it takes a recess, PL He criont A_ -fers inside danz IG ozmno radial and deliait 4 by an upstream collar and fine a-val that are part of the piece that rotates at most speed, a device

  _ 35 of the oil ju lquirements, a fin of

  yes is part of Ilmutra rotating part and done

253 1514

  protruding far enough into the recess to penetrate the liquid held in the recess by a centrifugal force and a pump mounted on the workpiece which rotates at the highest speed so as to be able to receive liquid from a reservoir or recess to drive the liquid at the speed of the workpiece and to introduce it into the recess in the area of this recess that is

  the closest to the outside in the radial direction.

  This arrangement-fact that, especially in a seal formed of two parts rotating in the opposite direction, there is more liquid entrained at the speed of the part which rotates at the fastest speed and that the liquid is subjected

  maximum centrifugal force which compensates for the

  In addition, if it is made that the device bringing the liquid to arrive at the inlet of the pump, the latter, after a

  any loss of liquid from the seal, reinitiate the recess-

  by delivering liquid at a centrifugal pressure

  maximum fugation, which will stop the passage of air

  at the level of the sealing fin.

  The pump is preferably constituted by vanes or by a porous element which ensures the positive drive

liquid.

  In one embodiment of the invention, the two parts which rotate relative to each other are the two axially rotating trees of a gas turbine and oil is used. as a liquid preventing

  the passage of air between the trees.

  The invention is described below in more detail by means of two exemplary embodiments with reference to the drawing. FIG. 1 is a view in axial section of a seal according to the invention placed between two shafts; Figure 2 is a sectional view similar to Figure 1 of another form of seal according to the invention placed between

two trees.

25315.14

  The shafts (1) and (2) shown in FIG. 1 rotate in the opposite direction, the shaft which is located furthest in the radial direction being the one rotating at the highest speed. The inner surface of this shaft outside comprises a recess (3) defined by the upstream flange (4) and the downstream flange (5) and between them The upstream downstream terms are defined with respect to the direction of flow of the gases, between the shafts, indicated by

the arrow (A).

  The inner shaft, which is the one that rotates

  the weakest, has an annular fin (6) which projects radially at its surface and extends far enough in the radial direction to penetrate the liquid held in the recess by the flanges The liquid arrives in the recess by a tube (7) which brings the

  liquid in the recess from its downstream end.

  The air flowing in the annular space between the shafts in the direction of the arrow (A) must pass over the edge of the shutter blade (6) to pass through the seal. Under these conditions, the collar (5) is sufficiently high, the centrifugal force acting on the entire height of the oil between the flange (5) and the fin (6) produces a pressure which is strong enough to overcome the pressure of the air exerted on the oil of the other

  end of the wing and realize a total blockage of the air.

  Because the shafts rotate in opposite directions the shutter vane exerts on the oil a pull due to the viscosity which opposes the driving force exerted

  by the surfaces of the recess This opposition tends to re-

  the average speed of the oil in the recess of a

  "sliding factor" which can be very high.

  slide, the apparatus is provided with a pump (9) which has the shape of vanes mounted between the downstream side of the flange (5) and another wall (10) projecting from 3.5 the shaft (2) and extending inward in the direction

  radial The liquid supply tube which, in the example de-

  crit, makes the liquid arrive at the downstream end of the recess, is mounted in such a way that it brings the liquid to the ends of the vanes which are located the innermost in the radial direction and constitute the inlet of the pump (9) The output of the pump passes the liquid, at the diameter of the recess which is the most outward in the radial direction, in an annular passage (12) which terminates in close proximity to the edge of the the fin

  6 If the ends of the blades are

  all the liquid that passes over the flange (5), it is possible to realize a re-circling circuit in the recess, the high-speed liquid coming from the annular passage (12) descending inwards through the free space (13) between the fin (6) and the wall (14) of the passage (12) The recycle stream can supplement or replace

  The pump supply (9) shows that the pump (9)

  traps the liquid positively at the rotational speed of the shaft (2) As a result, at least part of the oil reaches the maximum centrifugation pressure. The width of the annular passage (12) is equal to that of the expasse between the fin (6) and the base of the recess (3) so that the maximum centrifugal pressure can be achieved inside the oil in the entire

free space.

  The poop therefore increases the effectiveness of the seal by eliminating the slip factor inside the liquid, 9

  which intervenes in all the joints in which the rub-

  between the liquid and the surfaces of the recess con tain the only force driving the liquid It thus allows to produce a greater pressure inside the liquid

  for a lesser height of the liquid in the radial direction.

  In a gas turbine gasket with counter-rotating shafts 9 the liquid used is

  engine oil and the mixing of the oil by the aileron

  turning in the opposite direction causes it to warm up, so it is important to bring the recess

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  cold oil to prevent boiling or formation of

  oil in the oil, which would allow an air passage in the seal Orifices (8) provided upstream of the upstream flange (4) allow splashing oil produced upstream of this collar to pass into the mounted drains

upstream of the device.

  During the normal operation of the unit, the air pressure locked up is always dependent on the speed

  of the apparatus so that at low speeds, when the pressure

  centrifugation of the oil is low, the pressure of

  the air to which it must resist is also weak.

  However, if, for any reason, the oil supply is interrupted after the air pressure has reached its maximum value and if the seal is deficient, an extremely fast air jet would flow over the edge of the fin (6) so that at the moment o the arrival of oil would resume the oil could not reach the recess nor reach the full value of its centrifugal force On the other hand, in the joint provided with a pump which is the subject of the present invention, the pump drives the oil positively up to the maximum speed of rotation and pushes it into

  the recess under the maximum centrifugation pressure.

  As a result, the seal is rebooted.

  Another embodiment of a seal constituting a more particular solution of the problem is represented by FIG. 2. The parts of the joint identical to those of FIG. 1 are designated by the same references.

  embodiment, the height in the radial direction of the collar

  the downstream beam (5) is greater than the height in the radial direction of the wall (10) of the pump (9) located further downstream and all the oil supplied to the gasket arrives at the inlet of the pump annular passage (12) is delimited by the shaft (2) and a cylindrical sleeve (15) which extends upstream beyond the fin (6) and the passage (12) brings -35 the oil directly into the recess on the upstream side of the vane through the orifices (16) Pumping vanes

  epplmentaires (17) are mounted on the downstream flange (5).

  In these circumstances, after an operational incident,

  Due to a momentary loss of oil, when the arrival of the oil resumes, the oil is sent under a maximum centrifugal pressure on the upstream side of the airfoil.

  te (6) so as to reconstitute the joint.

Claims (2)

  1. Hydraulic joint between two parts that can rotate relative to each other, comprising a recess (3), oriented radially inwards and defined by an upstream collar (4) and a downstream collar (5). ) located on the part (2) which rotates at the highest speed, a device (7) supplying a liquid up to the recess (3), a sealing vane (6) 9 located on the other rotating part (1). ) and protruding far enough inside the recess (3) to penetrate the liquid held in the recess by the centrifugal force, characterized in that it further comprises a pump (9) rotating with the which runs at the fastest speed and rise of   to receive the liquid from the feeding device   ment (7) or recess (3) to entrain this liquid at the same speed as the workpiece (2) and to send it into the recess (3), in the zone which is closest to the outside in the radial direction 2.o Hydraulic seal according to claim 1, characterized in that the pospe (9) comprises blades mounted   on a wall (10) which extends radially towards the   the interior of the workpiece (2) which rotates at the highest speed. 3. Hydraulic seal according to claim 2, characterized in that the piece (2) which rotates at the highest speed comprises a wall (10) which extends in the radial direction towards the downstream int Ari and has a certain distance from the downstream flange (5) and in that vanes   extend between this wall (10) and the flange (5).   4 hydraulic seal according to claim 39 characterized in that it comprises an annular passage (12) defined by the outer edge, in the radial direction, 9 of the downstream flange (5) and the inner surface, oriented in the radial direction, of the corresponding piece (2), the outlet of the pump (9) being placed in such a way that the flow takes place through this passage (12). 5. Hydraulic seal according to claim 4, characterized in that the wall (10) radially inwards extends further inwards than the downstream collar (5).   6 hydraulic seal according to claim 3, characterized in that it comprises a cylindrical sleeve (15) surrounding, at a certain distance in the radial direction 9 the portion (2) of the seal which rotates at the largest speed and ending , from the end of its downstream end, in the radially inwardly directed wall (10), the radially inwardly extending wall (10) extending radially less than the downstream flange (5), the device (7) for supplying liquid to the recess (3) being mounted so as to bring the liquid to the ends of the innermost vanes (9) in the radial direction, these blades passing the liquid directly from the supply device (7) to the free space (10) between the sleeve (15) and the corresponding portion (2) of the seal and one or more orifices (8) being formed in this piece (2)   and permitting the penetration of the liquid, during the   in the recess (3) at its most   close to the outside in the radial direction.   7. Hydraulic seal according to claim 6, characterized in that the orifices (8) formed in the part (2) are upstream of the sealing fin (6) 8. Hydraulic seal according to any one of the   Claims 1 to 7, characterized in that the parts (1 and   2) which rotate relative to each other are two trees,   a gas turbine rotating relative to each other.   Hydraulic seal according to claim 8, characterized in that the shafts (1 and 2) rotate in opposite directions.