Untitled record

Method and Apparatus for Lubricating a Thrust Bearing for a Rotating Machine Using Pumpage

Background of the invention

This disclosure relates generally to pumps, and more specifically to thrust bearing lubrication to equalize an axial thrust force within a fluid machine suitable for normal operation but also useful for start-up, shutdown, and upset conditions.

The present section is intended merely to give background information to the present disclosure and does not constitute prior art.

Rotating fluid machines are used in many applications for many processes. Lubrication for a rotating fluid machine is an important matter. There are several types of fluid machines that use a thrust bearing that is lubricated by pumping. Sufficient pumping flow must be applied to obtain proper lubrication. Fluid machines are used in many cases. During normal operation, lubrication may be relatively easy. However, in various transient situations, such as air passing through the machine, lubrication may be lost and the fluid machine may malfunction. Drawing air or entering debris into the pump may cause irregularity.

Referring now to Figure 1, a hydraulic pressure booster (HPB) 10 is a type of fluid machine. The hydraulic pressure booster 10 is part of an integrated processing system 12 that also includes a processing chamber 14. Hydraulic pressure boosters may have a pump portion 16 and a turbine portion 18. A common shaft passage 20 extends between the pumping portion 16 and the turbine portion 18. The hydraulic pressure 10 may be free-running, meaning that its only source of energy is the turbine and it operates at any speed when there is the necessary balance between the turbine output torque and the pump input torque. The rotor or shaft passage 20 can also be connected to an electric motor to provide a predetermined rotation rate.

The hydraulic pressure booster 10 is used to boost the process feed stream using energy coming from another depressurized process stream through the turbine portion 18.

The pump portion 16 includes a pump impeller 22 housed within a pump impeller chamber 23. The pump impeller 22 is coupled to a shaft passage 20. The drive shaft 20 is carried by a bearing 24. The bearing is supported by a bearing 24 within a housing 26. Both the pumping portion 16 and the turbine portion 18 may share the same casing structure.

The pumping portion 16 has a pump inlet 30 to receive pumping and a pump outlet 32 to discharge fluid to the treatment chamber 14. Both the pump inlet and outlet 32 are openings within the casing 26.

The turbine portion 18 may include a turbine impeller 40 housed within a turbine fan chamber 41. The turbine impeller 40 is rotatably coupled to the shaft passage 20. The pump impeller 22, shaft 20 and turbine impeller 40 rotate together to form the rotor 43 The fluid flow enters the turbine portion 18 through the turbine inlet 42 through the casing 26. The fluid exits the turbine portion 40 through the turbine outlet 44 also through the casing 26. The turbine inlet 42 receives the high-pressure fluid and the outlet 44 supplies the fluid at low pressure due to the turbine fan 40.

The impeller 40 is housed in a fan shroud. The fan cover contains an inboard impeller shroud 46 and an outboard impeller shroud 48. During operation, the pump impeller 22, the shaft passage 20, and the turbine fan 44 are pushed towards the turbine portion 18. Figure 1, this is done in the direction of the propeller arrow 50. The impeller housing 48 is pushed in the direction of the thrust bearing 54.

The thrust bearing 54 can be lubricated with pumping fluid coming from the pump inlet 30 to the thrust bearing 54 through an external tube 56. A gap or layer of lubricating fluid can be placed between the thrust bearing 54 and the small outboard impeller shroud, which is represented by the line 55 between them. A filter 58 may be placed inside the pipe to prevent debris from entering the thrust bearing 54. Upon startup, the pressure in the pumping portion 56 will be greater than that of the thrust bearing and thus a lubricating flow will be supplied to the thrust bearing 54. During operation, the pressure inside the turbine portion 18 will increase and the fluid flow to the thrust bearing 54 must be reduced. Lubrication flow to the thrust bearing 54 may be insufficient during operation. Also, when the filter 58 becomes clogged, flow to the thrust bearing 54 may be obstructed. The thrust bearing 54 generates force during normal operation in the opposite direction of the arrow 50.

Referring now to Figure 2, it shows another hydraulic pressure booster according to prior art 10'. A 10' hydraulic pressure booster may have many of the same components shown in Figure 1, so the components in Figure 2 are numbered the same and are not explained again. In this example, the casing 26 has an annular clearance 60 in the space adjacent to the thrust bearing 54 and the outer turbine casing 48. This provides a small side flow of fluid to the thrust bearing 54 upon startup. One of the advantages of this process is the elimination of the external tube 56 and filter 58.

One of the difficulties of rotating fluid machines and thrust bearings is the high pressure in the pump, which may lead to a high axial thrust on the rotor in the direction of the turbine 18. Also, when starting operation, the pump is pushed During the pumping portion 16 using an external feed pump before the high-pressure booster 10 while the turbine portion is dry or nearly dry. Pumping fans may generate torque that causes the rotor to rotate, which may lead to failure of the thrust bearing due to lack of lubrication. In most cases, the pressure in the turbine portion is much lower than in the pump portion and thus lubrication may be insufficient until full rotation is achieved. Process equipment between the pump outlet and turbine inlet may occasionally introduce air into the turbine. This may occur when the treatment chamber or system does not fly properly upon startup. Consequently, intermittent lubrication of the thrust bearing may be lost.

Other application areas will become clear from the following description. It must be kept in mind that the detailed description and qualitative examples are intended merely to clarify and not limit the scope of the invention.

General description of the invention

The present section provides a summary of the disclosure, rather than a comprehensive disclosure of its scope and features.

The present disclosure provides a method for lubricating a rotating process machine during operation. The system provides pumping to the thrust bearing over the full range of operation of the device.

In one aspect of the invention, the fluid machine includes a pump portion having an impeller chamber, a pump inlet, a pump outlet, a turbine portion having a turbine impeller chamber, a turbine inlet and a turbine outlet. . The shaft passage extends between the pump impeller chamber and the turbine impeller chamber. The shaft passage has a channel for the drive shaft. The turbine fan is coupled to the driving end of the drive shaft placed inside the impeller chamber. The turbine fan contains vanes, at least one of which includes a blade duct.

In another aspect of the invention, the method of operating a fluid machine includes delivering fluid from a pump impeller chamber through the shaft passage to a thrust bearing at the inner end of the bearing and generating an internal axial force in response to the fluid delivery.

Other application areas will become clear from the following description. It must be kept in mind that the detailed description and qualitative examples are intended merely to clarify and not limit the scope of the invention.

Brief explanation of the drawings

The described drawings are intended for illustration only and are not intended to limit the scope of the present disclosure in any way.

Figure 1 is a cross section of a first turbocharger according to the prior art.

Figure 2 is a cross section of a second turbocharger according to the prior art.

Figure 3 is a cross-section of a first fluid machine according to the present disclosure.

Figure 4 is an end view of the propeller shown in Figure 3.

Figure 5 is a cross-section of a second fluid machine according to the present disclosure

Figure 6 is a cross section of a third embodiment of a turbine section according to the present disclosure

Figure 7 is a cross section of a fourth embodiment of a turbine section according to the present disclosure

Figure 8 is a cross section of an alternative embodiment of a turbine part according to the present disclosure0

Detailed description

The following description is merely representative and is not intended to limit the scope, application, or use of the present disclosure. For clarity, the same reference numbers will be used in the drawings to indicate similar items. As used in the present document, the statement of at least one of A, B, and C, logically intended (A, B, or C), using non-deficient logic, must be understood to mean that the steps of the method can be performed in a different order without changing the disclosure principles. Present.

In the following description, a hydraulic pressure booster with a turbine portion and a pump portion is shown. However, the present disclosure also applies to other fluid machines. The present disclosure provides a method for communicating pumping to a thrust bearing over the course of operation of the device. The rotor is used as a means of pumping to the surface of the thrust bearing. High pressure is provided to the thrust bearing from startup to shutdown including any changing conditions. Aggregate entry into the turbine is reduced.

Referring to Figure 3, a first model of a 10" high-pressure booster is shown. In this model, the common components from Figure 3 are indicated with the same reference numbers and we will not explain them again.

In this model, a 20' hollow shaft passage is used instead of the solid shaft shown in Figures 1 and 2. The hollow shaft 20' contains a shaft passage 70 that is used for pumping passage from the impeller chamber 23 of the pump portion 16 to the turbine portion 19. The passage 20 may provide pumping from the pump inlet 30.

The inboard shroud 46' contains radial passages 72. The radial passages 72 are fluidically coupled to the shaft passage 70. Although only two radial passages 72 are shown, several Country sewers.

The 40' impeller may have vanes 76a-d as shown in Figure 4. The 40' impeller has axial passages 74. Axial ducts 74 may be provided by vanes 76a and 76c of the 40' impeller. The axial runners are parallel to the HPB 10" axis of the shaft passage shaft 20'. The axial runners extend partially through the inner impeller shroud 46' and completely through the outer impeller shroud 48'. The axial runner 74 terminates near the thrust bearing 54. Again, the gap between the outboard impeller shroud 48' and the thrust bearing 54 is small and is therefore represented by line 55 in the figure between the two components. The thrust bearing lubrication path 54 includes a drive shaft passage 70, radial passages 72, and axial turbine impeller passages 74.

In operation, when the starting pressure inside the pump portion 16 is higher than the turbine portion 18, the fluid moves inside the pump portion through the shaft passage 70 to the radial passages 72 and to the axial passages 74. As fluid exits the axial duct 74, it is supplied to the thrust bearing 54. More specifically, the fluid lubricates the space or gap55 between the thrust bearing 54 and the outboard impeller shroud 48'. The thrust bearing 54 generates an internal axial force in response to the lubricating fluid in the opposite direction of the arrow 50.

The highest pumping pressure occurs at pump inlet 30 at startup. The ducts after the pump inlet are at a lower pressure and the fluid then flows from pump portion 16 to turbine portion 18. Therefore, pumping from the inlet is higher at startup. When the device is shut down, the same factors apply due to the pressure difference between the pump and turbine. During normal operation, the highest pressure is not at the pump inlet, but rather at its outlet 32. Due to the arrangement of the lubrication ducts, the pressure in the pumping increases due to the high pressure occurring in the radial passage 72 due to the centrifugal force generated by the rotation of the turbine impeller 40'. The amount of pressure generation is determined by the length of the diagonal of the radials 72 and the rotation rate of the rotor. Thus, pumping is provided to the thrust bearing at start-up, in normal operation, and when the fluid machine 10 is shut down.

Referring now to Figure 4, it shows a 40' impeller containing four vanes 76a-76d. Different numbers of feathers can be added. The vanes extend axially relative to the 20' shaft axis. There may be more than one fan with an axial duct 74. The axial passages 74 extend through the vanes 76 and the inner fan casing 46', which is sufficient to obstruct the radial passage 72 and the outer fan casing 48', as shown in Figure 3.

It should be noted that treatment room 14 is suitable for various types of operations including reverse osmosis system. For a reverse osmosis system, the treatment chamber may have a membrane 90 placed within it. The resulting permeable material can be supplied into the treatment chamber so that demineralized fluid can flow from it. A brine fluid may enter the turbine inlet 42. Of course, as previously indicated, it is possible to provide for various types of operations including natural gas processing and the like.

Referring to Figure 5, it shows a model similar to the one shown in Figure 3 and therefore contains the same reference numbers. In this embodiment, a deflector 110 is provided within the pump inlet 30. The deflector 110 may be coupled to the pump impeller 22 using supports 112. The supports may hold the deflector 110 away from the pump impeller such that a gap is formed between them that allows fluid to flow into the shaft duct through the shaft passage 70.

The deflector 110 may be cone-shaped and have a tip 114 positioned along the shaft passage 20'. The conical shape of the deflector 110 will deviate the direction of the aggregate in the pumping to the pumping fan 22 and thus prevent the passage of the aggregate into the shaft passage 70. In contrast to the filter 58 shown in Figure 1, it deflects the aggregate away from the shaft passage 70. , thus it will not lead to blockage of the drive shaft duct 70.

Now referring to Figure 6, it shows turbine part 18 and has another model of thrust bearing 54'. The thrust bearing 54' may have an outer space behind the cutting edge 210 and an inner space behind the inner land 212. A fluid cavity 214 is formed between the outer land 210, the inner space 212, and the outer shroud 48'. It should be noted that the thrust bearing 54' shown in Figure 6 can be included in the models shown in Figures 3 and 5.

The outer space behind the cutoff 210 is positioned adjacent to the annular clearance 60. The inner space beyond the cutoff 212 is positioned adjacent to the turbine outlet 44. The thrust bearing 54' may be annular in shape and thus both outer spaces that Behind the cutting edge 210 and the inner space behind the cutting edge 212 are also toroidal in shape.

Cavity 214 can receive pressure-conditioning fluid from the pump portion 16 shown in Figures 3 and 5. That is, pumping can be received through the shaft passage 70, radial passages 72 and axial passages 74.

Slight axial movements of the shaft passage shaft 20 in the connected impeller shroud 48' may cause variations in the axial clearance 220 between the spaces behind the cutting edge 210 and 212 relative to the outboard impeller shroud 48'. If the axial clearances 220 increase, the pressure in the fluid cavity 214 decreases due to increased leakage through the clearances 220. Conversely, if the axial clearances 220 decrease, the pressure in the fluid cavity 214 will increase. The pressure differential equalizes the variable axial thrust generated during operation and ensures that chambers 210 and 212 do not come into contact with the impeller 48' housing.

The pressure drop is determined by the resistance to flow in the sewer 70-74. The sewer is sized to provide a relationship between the leakage rate and the change in fluid cavity pressure 214 as a function of axial clearances. The diagonal position of the channel 74 determines the amount of pressure increase generated by the centrifugation and is taken into account to ensure optimal leakage in addition to the diameters of the flow channel. Excessive leakage may impair efficiency and insufficient fluid flow will make the clearance too small and allow frictional contact during operation.

The pressure in the fluid cavity is higher than the turbine outlet 44 and the pressure in the outer diameter of the propeller is at annular clearance 60 when the duct 74 is in the optimum radial position. Therefore, the leak will be from the cavity 214, allowing the required pressure to vary within the fluid cavity 214.

Now referring to Figure 7, it shows an embodiment similar to the one shown in Figure 6. The inner space 212 is replaced by a bushing 230. The bushing 230 may form a cylindrical clearance with respect to the impeller wear ring 232. Therefore the fluid cavity 214 is defined between the wear ring ring 232, bushing 230, and outer space 210.

Referring now to Figure 8, it shows a vane 240 of a propeller 242 having curvature in the axial plane as well as the radial plane. The impeller 242 can be used in a mixed flow design. In this embodiment, the outer space 210' and the inner space 212' are formed by the shape of the fan 242. Also, the fluid cavity 214' may be irregularly shaped between the outer space 210' and the inner space 212'.

Fluid duct 250 supplies fluid directly into the fluid cavity 214' at an angle to the longitudinal axis of the fluid machine and shaft passage 20'. Therefore, the radial passages 72 and axial passages 74 are replaced by an inclined passage 250. The inclined passage 250 can enter the fluid cavity 214' at various positions including near the space 212' or at another position such as near the space 210 '. There are also different places between space 210' and 212' that can receive the diagonal passage 250.

Those currently skilled in the art will recognize from the foregoing description that the general detection instructions can be applied in different ways. Therefore, although the present disclosure includes certain examples, its actual scope should not be limited to these because there are other modifications that will become clear to the skilled practitioner upon studying the drawings, description, and subsequent safeguards.