JP2003307195A - Fluid machine having hydrostatic bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fluid machine having a hydrostatic bearing displaying satisfactory bearing performance during transient and rated operation time, being maintenance-free by extending the bearing's service life. <P>SOLUTION: The fluid machine having a rotation axis 2 and the hydrostatic bearings 3, 4 for supporting the axis 2 comprises fluid passages 6 for supplying the hydrostatic bearings 3, 4 with fluid boosted by the fluid machine, a pressure- accumulating device 8 capable of accumulating pressure fluid inside, and pressure accumulating passages 9 for connecting the hydrostatic bearings 3, 4 with the pressure-accumulating device 8. Regulating valves 10 are provided on the pressure accumulating passages 9 for regulating flow of pressure fluid flowing through the pressure accumulating passages 9. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid machine equipped with a hydrostatic bearing, and more particularly to a petroleum refining system that operates continuously for a long time
The present invention relates to a fluid machine having a hydrostatic bearing used in petrochemical and other general industries.

[0002]

2. Description of the Related Art A bearing is used to support a rotating shaft in a fluid machine such as a pump, but this bearing is used in equipment for petroleum refining, petrochemicals, and other general industries that operate continuously for a long time. Prolonging the service life is an important factor for making maintenance free. In recent years, it has been widely practiced to extend the life of bearings by using hydrostatic bearings that are less worn as bearings for pumps. Such a hydrostatic bearing supplies a pressurized fluid to a small chamber called a pocket, and utilizes the static pressure of the pressurized fluid supplied to the pocket to support the rotating shaft in a non-contact state.

FIG. 5 is a schematic diagram showing a fluid path in a pump having a conventional hydrostatic bearing. In the pump shown in FIG. 5, a main shaft (rotary shaft) 120 is supported in a casing 130 by two hydrostatic bearings 100 and 110, and an impeller 140 attached to the main shaft 120 pressurizes a fluid to be handled. It is like this. In the pockets 100a and 110a of the hydrostatic bearings 100 and 110,
A part of the handled fluid whose pressure is increased by the impeller 140 is supplied through the handled fluid channel 150, and the main shaft 120 is supported in a non-contact state by the static pressure of the handled fluid.

[0004]

However, when the handling fluid whose pressure is increased in the pump is used as the pressurized fluid supplied to the hydrostatic bearing as in the example shown in FIG. 5, the pump is stopped. When the pump rotation speed is low during startup (hereinafter referred to as transient operation), the discharge pressure of the pump is not sufficient, so the fluid pressure supplied to the hydrostatic bearing is low, and the hydrostatic bearing is sufficient. Bearing performance cannot be demonstrated. Therefore, during such a transient operation, the rotary shaft is not sufficiently supported by the hydrostatic bearing and comes into contact with the hydrostatic bearing, and wear shortens the life of the hydrostatic bearing. Particularly, at the time of starting a pump having a high head, it may take several minutes to pressurize the fluid to be handled until the pressure of the hydrostatic bearing reaches a sufficient bearing performance.

In order to prevent the contact between the rotary shaft and the hydrostatic bearing during such a transient operation, wear of the rotary shaft and the hydrostatic bearing is suppressed by appropriately combining the materials of the rotary shaft and the hydrostatic bearing. The clearance with the pressure bearing is increased to avoid contact.
However, it is difficult to select an appropriate material, and
When the clearance between the rotary shaft and the hydrostatic bearing is increased, the bearing performance of the hydrostatic bearing during steady operation deteriorates.

The present invention has been made in view of the above-mentioned problems of the prior art, and exhibits sufficient bearing performance during transient operation and steady operation to prolong the life of the hydrostatic bearing and make it maintenance-free. An object is to provide a fluid machine including a hydrostatic bearing that can be realized.

[0007]

In order to solve the problems in the prior art, the first aspect of the present invention is
In a fluid machine having a rotary shaft and a static pressure bearing supporting the rotary shaft, a handling fluid channel for supplying a handling fluid whose pressure is increased by the fluid machine to the static pressure bearing, and a pressure fluid can be stored inside It is a fluid machine provided with a static pressure bearing characterized by having a pressure accumulation device and a pressure accumulation channel which connects the static pressure bearing and the pressure accumulation device.

With such a configuration, during transient operation of the pump, the pressure fluid accumulated in the pressure accumulator can be supplied to the hydrostatic bearing, and the rotary shaft can be supported by the pressure of this pressure fluid. The contact between the shaft and the hydrostatic bearing can be prevented, and the impact due to a sudden touchdown can be prevented from being applied to the hydrostatic bearing. Therefore, it is possible to extend the life of the hydrostatic bearing and realize maintenance-free.

In a preferred aspect of the present invention, an adjusting valve capable of adjusting the flow rate of the pressure fluid flowing through the pressure accumulating passage is provided on the accumulating passage.

According to a second aspect of the present invention, in a pump having a rotary shaft and a static pressure bearing for supporting the rotary shaft, a handling fluid flow path for supplying a handling fluid pressurized by the pump to the static pressure bearing. A pressure fluid supply source capable of supplying a fluid of a predetermined pressure, an auxiliary flow path connecting the static pressure bearing and the pressure fluid supply source, and a control valve for opening and closing the auxiliary flow path. A fluid machine equipped with a characteristic hydrostatic bearing.

With this configuration, during transient operation of the pump, a fluid having a predetermined pressure can be supplied to the hydrostatic bearing from the pressure fluid supply source, and the rotary shaft can be supported by the pressure of the pressure fluid. The contact between the rotary shaft and the hydrostatic bearing can be prevented, and the impact due to a sudden touchdown can be prevented from being applied to the hydrostatic bearing. Therefore, it is possible to extend the life of the hydrostatic bearing and realize maintenance-free.

A preferred aspect of the present invention is characterized by having a control device for sending a control signal to the control valve.

In a preferred aspect of the present invention, a check valve for preventing the handling fluid from flowing from the hydrostatic bearing toward the pressure fluid supply source is provided on the auxiliary flow path. .

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a fluid machine having a hydrostatic bearing according to the present invention will be described below with reference to FIGS. In the following, a pump will be described as an example of a fluid machine including a hydrostatic bearing, but the present invention is not limited to this and the present invention can be applied to various fluid machines.

1 and 2 are schematic views showing fluid paths in a pump according to the first embodiment of the present invention. As shown in FIGS. 1 and 2, the pump according to the present embodiment includes a casing 1, a main shaft (rotating shaft) 2 arranged inside the casing 1, and two static pressure bearings 3 and 4 supporting the main shaft 2. It has and. An impeller 5 is attached to the main shaft 2, and the handling fluid is pressurized by the impeller 5.

The hydrostatic bearings 3 and 4 are respectively connected to a fluid handling channel 6 for supplying a part of the fluid handled by the impeller 5 to the hydrostatic bearings 3 and 4. Part of the pressurized fluid to be handled is supplied to the pockets 3a, 4a of the hydrostatic bearings 3, 4. A check valve 7 is provided on the treated fluid passage 6 to prevent the treated fluid from flowing from the hydrostatic bearings 3 and 4 toward the impeller 5.

A pressure accumulator 8 such as an accumulator capable of accumulating a pressure fluid is connected to the hydrostatic bearings 3 and 4. That is, the pockets 3a, 4 of the hydrostatic bearings 3, 4
a is connected to the pressure accumulator 8 via the pressure accumulator channel 9, respectively, so that the handling fluid supplied to the pockets 3a, 4a of the hydrostatic bearings 3, 4 can be accumulated inside the accumulator 8. There is. An adjusting valve 10 capable of adjusting the flow rate of the handling fluid flowing through the pressure accumulating passage 9 is provided on the pressure accumulating passage 9.

During steady operation of the pump, the handling fluid whose pressure has been increased by the impeller 5 is supplied to the pockets 3a, 4a of the hydrostatic bearings 3, 4 via the handling fluid passage 6, respectively, and the pressure of the handling fluid causes the spindle to rotate. 2 is supported in a non-contact state. The handling fluid supplied to the pockets 3a and 4a of the hydrostatic bearings 3 and 4 is also supplied to the pressure accumulator 8 via the pressure accumulator channel 9 as shown by an arrow A in FIG.
The pressure is accumulated inside.

When the pump is stopped, the pressure of the fluid to be handled discharged from the impeller 5 is drastically reduced with the decrease of the pump rotation speed and is supplied to the pockets 3a, 4a of the hydrostatic bearings 3, 4. However, in the present embodiment, as shown by an arrow B in FIG. 2, the pressure fluid accumulated in the pressure accumulator 8 is gradually fed to the hydrostatic bearing via the adjusting valve 10. Supply to 3, 4 pockets 3a, 4a. As a result, the pressure of the fluid in the pockets 3a, 4a of the hydrostatic bearings 3, 4 does not drop sharply but gradually drops. Therefore, the pump can be smoothly stopped without giving a shock due to a sudden touchdown to the hydrostatic bearings 3 and 4.

In this embodiment, the handled fluid is stored in the pressure accumulator 8 during steady operation, but the pressure fluid may be accumulated in advance in the pressure accumulator 8 using an external pressure source.

FIG. 3 is a schematic diagram showing a fluid path in a pump according to the second embodiment of the present invention. Note that FIG.
In FIG. 1, the same or corresponding components as those shown in FIG. 1 are designated by the same reference numerals, and duplicated description will be omitted.

As shown in FIG. 3, a pressure fluid supply source 11 capable of supplying a fluid of a predetermined pressure is connected to the hydrostatic bearings 3 and 4 of this embodiment. That is, the pockets 3 a and 4 a of the hydrostatic bearings 3 and 4 are connected to the pressure fluid supply source 11 via the auxiliary flow path 12, respectively. This auxiliary flow path 12
Above, a regulating valve 13 that opens and closes the auxiliary flow path 12 based on a control signal from a control device (not shown), and a handling fluid flows from the static pressure bearings 3 and 4 toward the pressure fluid supply source 11. A check valve 14 is provided to prevent this. As the pressure fluid supply source 11, for example, a nitrogen gas supply source (nitrogen cylinder) or a pump can be used.

At the time of starting the pump, the control valve 13 is opened based on the control signal from the control device, and the fluid of a predetermined pressure is supplied from the pressure fluid supply source 11 to the pockets 3a of the hydrostatic bearings 3 and 4,
4a. The pressure of this fluid is set to be substantially the same as the pressure of the fluid to be handled supplied to the hydrostatic bearings 3 and 4 during steady operation, and the main shaft 2 is not contacted by the pressure of the fluid from the pressure fluid supply source 11. Be supported by the state. The main shaft 2 is driven by the pressure fluid from the pressure fluid supply source 11.
Is supported, the main shaft 2 is rotated and the handling fluid is pressurized by the impeller 5.

As the pump rotational speed increases, the discharge pressure of the impeller 5 increases, and when the hydrostatic bearings 3 and 4 are boosted to a pressure at which they have sufficient bearing performance, a control signal from the control device is sent. Based on this, the control valve 13 is closed to perform a steady operation. In this steady operation, the main shaft 2 is supported in a non-contact state by the pressure of the handling fluid boosted by the impeller 5. Thus, according to this embodiment, the hydrostatic bearings 3,
Since the pump can be started in a state where the main shaft 2 and the main shaft 2 are not in contact with each other to prevent wear of the static pressure bearings 3 and 4, the life of the static pressure bearing can be extended and maintenance-free can be realized.

When the pump is stopped, the control valve 13 is opened based on the control signal from the control device, and the pressure fluid supply source 1
1 to a fluid of a predetermined pressure, the pockets 3 of the hydrostatic bearings 3 and 4
a, 4a. If you stop the pump in this state,
It is possible to maintain the pressure of the fluid in the pockets 3a, 4a of the hydrostatic bearings 3, 4 by the pressure fluid from the pressure fluid supply source 11 regardless of the sudden decrease in the pressure of the handled fluid discharged from the impeller 5. it can. Therefore, the pump can be smoothly stopped without giving a shock due to a sudden touchdown to the hydrostatic bearings 3 and 4.

As described above, the present invention can be applied to various fluid machines, but is suitable for use, for example, in a vertical multistage pump as shown in FIG. Such a vertical shaft multistage pump is used, for example, to pressurize the liquefied gas in a liquefied gas tank that stores the liquefied gas such as liquefied natural gas (LNG) or liquefied petroleum gas (LPG) and discharge the liquefied gas to the outside.

The vertical multistage pump shown in FIG. 4 comprises a suction casing 20, a plurality of pump casings 21 and a motor casing 22. These suction casing 20, pump casing 21 and motor casing 2
2 is housed inside a cylindrical pump column 23. The cylindrical pump column 23 is suspended, for example, inside the liquefied gas tank via a wire or the like.

Inside the casings 20, 21, and 22,
A main shaft (rotating shaft) 24 is rotatably accommodated via an upper ball bearing 30, an upper static pressure bearing 31, an intermediate static pressure bearing 32, an intermediate ball bearing 33, and a lower static pressure bearing 34. Inside the suction casing 20 and the pump casing 21,
A plurality of (six in FIG. 4) impellers 2 fixed to the main shaft 24.
5a to 25f are arranged. Motor casing 22
A motor stator 26 is arranged inside the motor, and a motor rotor 27 is fixed to the main shaft 24 so as to face the motor stator 26.

The fluid sucked from the suction casing 20 is sequentially pressurized by the impellers 25a to 25f at the respective stages, and then the discharge passage 4 formed inside the pump column 23.
0, and is discharged to the outside from a discharge pipe (not shown) connected to this discharge flow path 40.

The suction casing 20 includes a lower static pressure bearing 34.
A handling fluid channel 41 for the impeller 2 is formed.
The handling fluid whose pressure has been increased in 5 b is supplied to the lower hydrostatic bearing 34 via the handling fluid flow path 41. Further, the motor casing 22 includes an intermediate static pressure bearing 32.
And a handling fluid passage 43 for the upper static pressure bearing 31 are formed, and the handling fluid pressurized in the impeller 25c passes through the handling fluid passage 42 at an intermediate static pressure. The handling fluid supplied to the bearing 32 and flowing through the discharge passage 40 is supplied to the upper static pressure bearing 31 via the handling fluid passage 43.

In the pump shown in FIG. 4, the hydrostatic bearing 3
Ball bearings 30, 3 as auxiliary bearings for 1, 32, 34
3 is provided. These ball bearings 30, 33
Supports the main shaft 25 during transient operation, and has a structure such that no load is applied during steady operation.

Although one embodiment of the present invention has been described so far, it is needless to say that the present invention is not limited to the above embodiment and may be implemented in various different forms within the scope of the technical idea thereof.

[0033]

As described above, according to the present invention, during the transient operation of the pump, the pressure fluid accumulated in the pressure accumulator is supplied to the hydrostatic bearing or a predetermined pressure is supplied from the pressure fluid supply source. Since fluid can be supplied to the hydrostatic bearing and the rotary shaft can be supported by the pressure of this pressurized fluid, contact between the rotary shaft and the hydrostatic bearing can be prevented, and the impact due to a sudden touchdown can be generated by the hydrostatic bearing. Can be prevented from joining. Therefore, it is possible to extend the life of the hydrostatic bearing and realize maintenance-free.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a fluid path in a pump according to a first embodiment of the present invention.

FIG. 2 is a schematic diagram showing a state in which the pump of FIG. 1 is stopped.

FIG. 3 is a schematic diagram showing a fluid path in a pump according to a second embodiment of the present invention.

FIG. 4 is a vertical sectional view showing a vertical shaft multi-stage pump suitable for the present invention.

FIG. 5 is a schematic diagram showing a fluid path in a pump including a conventional hydrostatic bearing.

[Explanation of symbols] 1 casing 2,24 Spindle 3,4 Hydrostatic bearing 3a, 4a pockets 5 impeller 6 Handling fluid channel 7,14 Check valve 8 Pressure accumulator 9 Pressure accumulation flow path 10,13 Regulator valve 11 Pressure fluid supply source 12 Auxiliary flow path 20 Suction casing 21 Pump casing 22 Motor casing 23 pump columns 30, 33 ball bearings 31, 32, 34 Hydrostatic bearings 25a-25f impeller 26 Motor stator 27 motor rotor 40 discharge channel 41, 42, 43 Handling fluid channel

Claims (5)

[Claims] 1. A fluid machine having a rotary shaft and a hydrostatic bearing for supporting the rotary shaft, wherein a fluid handling path for supplying a fluid handled by the fluid machine to the hydrostatic bearing, and a pressure inside the fluid channel. A fluid machine equipped with a hydrostatic bearing, comprising: a hydrostatic device capable of accumulating a fluid; and a hydrostatic bearing that connects the hydrostatic bearing and the hydrostatic device. 2. A fluid machine having a hydrostatic bearing according to claim 1, wherein an adjusting valve capable of adjusting a flow rate of the pressure fluid flowing through the pressure accumulating passage is provided on the pressure accumulating passage. 3. A fluid machine having a rotary shaft and a static pressure bearing for supporting the rotary shaft, wherein a handling fluid flow path for supplying a handling fluid pressurized by the fluid machine to the static pressure bearing, and a predetermined pressure. A pressure fluid supply source capable of supplying the fluid, an auxiliary flow path connecting the static pressure bearing and the pressure fluid supply source, and a control valve for opening and closing the auxiliary flow path. Fluid machinery with pressure bearings. 4. A fluid machine having a hydrostatic bearing according to claim 3, further comprising a control device that sends a control signal to the control valve. 5. A check valve for preventing the handling fluid from flowing from the static pressure bearing toward the pressure fluid supply source is provided on the auxiliary flow path. A fluid machine equipped with the hydrostatic bearing according to claim 1.