DE2043550C2 - Control device for the axial thrust compensation of a hydrodynamic thrust bearing arrangement - Google Patents

Description

The invention relates to a control device for the centrifugal compressor.

AxTälschublTgfeSh a hydrodynamic pressure load- The centrifuge shown> ™ ^ r »t d ^ em

«Sranordnune is designated by 10 according to the preamble of patent no. 35 and has a shaft ii, which is shown in

r ^ chs cylinder bearings 12a and 13a is rotatably supported by

In the case of machines running at high speed, such as those where a surface 14a or 15a is part of a loading

Zemrifugal pumps, compressors, turbines, turbo-known pressure bearing types and d.e to a plane

“Bubbles and thrust bearings are the main cause of surface rotating, disc-shaped thrust bearings 14

S ^ nSirStemeVd. der'auf the shaft engages 40 or 15, which are fixedly arranged on the shaft 11.

pressure due to many factors, such as B. Compression The bearing assemblies, i.e. consisting of the cylinder bearings 12a

or Las changes in the machines as well as bad and 13a and thrust bearings 14 and 15 will exist

Sealing constructions, relatively large fluctuations through lubrication channels 16 and 17 lubricated, themselves

"Nterlieet ^{through the} cylinder bearings 12a and 13a and into the

In contrast to cylinder bearings, which encircle 45 cylinder bearing gaps 12b and 136 between shaft 11

De have peripheral bearing surface, have thrust bearings ra- and cylinder bearings 12a and 113a extend into it.

dfal directed! Surfaces on. This has the consequence that the lubricant from the container 18 is over the

then if the lubrication is momentarily interrupted, pump 19, cooler 20, filter 21 and the pressure

the centrifugal force acts to the effect that the remaining regulator 21a circulates, through flow constrictions

before lubricating oil is thrown to the outside, whereby 50 22 and 23 are promoted and then in the Schm.ermitlel-

the lubricated metal surfaces run dry. channels 16 and 17 pumped The ^ lubricant that is in d.e

In the generic prior art, it is cylinder bearing gaps 12i> and 13i> is printed in,

known to flow in the axial direction along the shaft 11, the pressure acting on the shaft.

calculate and an axial thrust compensation device in front of a part in the bearing gaps 24 and 25 between d.e

see that the calculated pressure of the thrust is neutral. - 55 mating faces of the bearing assemblies

or the pressure differences that occur at least occur and lift radially between the surfaces to the outside

keeps it low. In those cases, however, in which the Druckbe- and escapes into the storage chamber 11a, in which it is through

load is not known, such a compensation pre-flow 11b in the line lic and the container

direction of little value. So far there are no simple runs back.

or exact procedure for measuring the pressure 60 The strength of the lubricant flow w.rd through the load has become known, which in connection with a constrictions 22 and 23 limits' The co-pasner Control device for the axial thrust compensation have bearing surfaces on their Ausnttskan en A dynamic thrust bearing arrangement also uses constrictions 26 and 27, which are stronger could become. In this context, the loss of lubricant from the bearing arrangement «1 book the blolk draining of the pressure medium from the La- μ is prevented. As can be seen from the drawing, form Kcrspall or 'the axial stroke generating chamber, the constrictions 26 and 27 lips, which are around and its return to the impeller as one of the circumference of the thrust bearing surfaces of the cylinder bearings unsatisfactory method of balancing the 12a and 13a extend. You can tell that if

f | the lubricant is pressed into the arrangement, ■ | j any displacement of the shaft 11 in the direction of the ί Cylinder bearings 12a to increase the flow resistance of the lubricant between the | j lip of the constrictions 26 and the thrust bearing 14

I leads and a lubricant pressure build-up in the bearing

II gap 24 results in the pressure distribution is not || necessarily uniform, but depends on the type of storage, it being known where the ι * pressure build-up zone is located, so that the lines 28, 29, ξ \ with which the pressure build-up zone is tapped, are arranged accordingly.

The increase in pressure in the bearing gap 24 tends to that J? rotating thrust bearing 14 from the pressure surface of the Zy-Il linderlagers 12a as part of the Drucklageranordp voltage so long to push away until the game between the ρ lip of the constriction 26 and the thrust bearing 14! ' is posed.

ψ Since, as can be seen from the drawing, two opposing

| I opposite thrust bearing arrangements exist, j | in order to maintain the axial position of the shaft 11, the B pressure measurement, as described for the thrust bearing 14 in the above; | is described, can also be made with respect to the thrust bearing 15 with the help of the line 29, which is connected to the ty, pressure build-up zone. ;. occurs, is essentially the same, any axial displacement of the shaft 11 is recognizable by a pressure change in the bearing gaps 24 and 25. If the shaft If 11 shifts, for example, in the direction of the cylinder bearing 12a, the pressure in increases Bearing gap 24 with respect to R; to that in bearing gap 25. Accordingly, by measuring the pressure difference between the bearings - .; ".;■; columns 24,25, which can be made with the help of the differential pressure measuring device 30, which is connected to the lines I '''28 and 29, causes a direct display of the axial pressure on the shaft 11, which the [_ is received by the two opposite Drucklageranordj ί voltages reflected in the different axial thrust.

:>: The compressor 10 shown in the drawing

ijj has an impeller 31 which is mounted on the shaft 11 and rotates with it. The fluid to be compressed enters at the compressor inlet opening 32 and is ^{discharged at the compressor outlet opening 33:} after its radial outward passage through the channels in the impeller 31, the compressed fluid collecting in the channels 35 before it passes through the outlet opening 33 flows out. Much of the pressure increase in the fluid that is compressed as it flows through the impeller channels 34 so that the fluid pressure in channel 35 is much greater than that in inlet port 32. The high pressure in channel 35 is largely also in the Transfer gap 36 between the end face of the impeller 31 and the housing of the compressor 10. This gap is closed at its inner edge by a labyrinth seal 38. This seal lets a small amount of fluid out of the gap 36 and returns it via the inlet opening 32 to the suction area. The effect of this small amount of leakage, which makes up only a few percent of the total flow, on the system is negligible.

In a similar way, the high pressure prevailing in the channels 35 is largely propagated into the gap 37, which is present between the rear side of the impeller 31 and the housing of the compressor 10 to penetrate into the gap 40. When the compressor is in operation, however, this small amount of leakage, which flows through the labyrinth seal 39 via the gap 37, poses a considerable problem due to the fact that, as soon as it enters the gap 40 between the rear of the impeller 31 and the housing of the compressor 10 has penetrated, is pressed over the surface of the rear side of the impeller 31 within the seal 39, which can result in a considerable axial thrust which is exerted on the impeller 31 and pushes the impeller away from the shaft 11 because the Area on the opposite side within the seal 38 is not pressurized to compensate for this axial thrust. In order to eliminate this axial thrust problem, a compensation system is provided in machines of the type mentioned rotating at high speed, with which this pressure can be relieved, thereby preventing serious damage to the bearings. Such a pressure equalization arrangement shown in the drawing has an expansion line 41 which leads from the gap 40 to the expansion line 42 and via the valve 43 to open from there via the line 44 into the suction port of the inlet opening 32 of the cortipressor 10. The valve 43 is normally open so that the fluid which has just been compressed, which is being forced into the gap 40, can flow back to the suction port of the inlet opening 32. The amount of leakage which flows into the gaps 36 and 37 changes, however, as a function of the roughness of the connected lines and the amount of leakage passing through the seal 39. The mere withdrawal of the fluid from the gap 40 and its return into the inlet opening 32 via the line 41, the line 42, the valve 43 and the line 44 is therefore not sufficient to compensate for the axial thrust, so that to avoid this disadvantage in the Bearing gaps 24 and 25 connecting lines 28 and 29, a differential pressure measuring device 30 is installed, which is connected to the valve 43 in such a way that the measured variable of the differential pressure measuring device 30 is supplied as an actuator for the automatic adjustment of the valve 43 to thereby achieve the desired axial thrust compensation cause.
The above construction is based on the consideration that when the thrust is directed against the shaft and away from the inlet opening of the impeller 31, the pressure prevailing in the gap 40 is obviously less than it should be, or the fluid is too unimpeded in the inlet opening 32 can flow back. To avoid this, the valve 43 could now be closed somewhat, thereby somewhat inhibiting the flow of fluid from the gap 40 into the lines 41 and 42 and keeping the pressure in the gap 40 high enough to keep the impeller 31 off the shaft move away. If, on the other hand, the pressure in the gap 40 is less than it should be, whereby the shaft ti is pushed away from the impeller 31 by a slight unbalanced shock, then the pressure in the bearing gap 24 increases, while it decreases in the bearing gap 25. This change in the relative pressures of the two bearing gaps is detected immediately by the differential pressure measuring device 30. If the differential pressure measuring device 30 is used as a differential pressure writing or differential

j ^ tamat ^ inr

pressure control device is formed with a device for automatically adjusting the valve 43 is provided, as is the case here, then the pressure in the gap 40 can always be at the desired level Maintain height regardless of the changes in axial thrust that occur in the system th can. Thus, by allowing some fluid outflow from gap 40, a precise control of the thrust acting on the rotating system is achieved.

1 sheet of drawings

15th

20th

25th

40

45

50

55

60

65

Claims (1)

Axial pressure or thrust proved. Patf-ntansnruch Although it is an arrangement for the relief of Claims. ^ Support bearings known (AT-PS 2 04 335) with the one Control device for the axial thrust compensation ei- thrust bearing through a ^ gSSS "S £ ner hydrodynamic thrust bearing arrangement of a 5 one of the shaft ZZ ™ to the bearing package via! ^ Supply line, o pressure chamber connected manometer only to measure the lubricant build up a pressure, solution of a compressed air cushion is used, with the help of which the shaft is raised or lowered via a shaft connected to the bearing gap abTreifbär is, whereby the hydrodynamic From GB-PS 6 93 021 it is schheßhch also LaeeranordnSngTn a stationary housing knows the axial thrust on the bearing e.ner Turb.nenwe Ie tSd aSS that, together with each housing, “by a pressure-dependent actuated valve” axially movable valve with a seal without the need for a suitable measuring device A sealed, axial thrust generating gap is provided, the determined pressure behavior ' The flow connection with the impeller adds nits as control variables for the Ax.alschubausgle.ch 7ii «: flowing conveying means as well as with one to use. ,, ".-. · LaSeTnS leading relaxation line 20 The object of the invention is therefore d, e ϋΐΠβϊβ contains a valve, thereby forming a control device of the type mentioned so that the two are connected to the bearing gap over the differences measured in the location gaps? 245) connected lines (28,29) via pressure an automatic induction of the axial differential pressure measuring device (30) with each other Tent claim solved With this solution it is achieved, SSSdfühmng de! Axialschubausgleichs to-that the axial position of the shaft of the Strömungsmasch.ne 7 ^{"erDeirunru" 6 6 u} he _unt all operating conditions maintained w.rd. SSSdfühmng de! Axialschubausgleichs to-that the axial position of the shaft of the flow rh H7R ^{"erDeirunru" 6 6 u} he _unt all operating conditions maintained w.rd. iunrDarisi. ^ The _{invention is} explained in more detail below with reference to the embodiment shown in the drawing, which is a partially sectioned view of an iflk it provided with the control device according to the invention the gg