JPH11223197A - Pump device for liquefied gas - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pump device, in which improvement in a bearing life and reliability, reduction in costs, prevention of abnormal abrasion in ball bearings arranged in a plural lines can be accomplished for long-term stable operation, for liquefied gas. SOLUTION: A pump device is constructed of a pump shaft 5A, a driving unit rotationally driving the pump shaft 5A, an impeller 5c, which is arranged below the driving unit along the pump shaft 5A and increases a pressure of sucked liquefied gas, a discharge port, from which liquefied gas pressurized by means of the impeller 5C is discharged, a plurality of bearings supporting the pump shaft 5A and the like. In the bearing unit of the pump device, single- row ball bearings are arranged in a plurality of lines.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a liquefied gas pump device, and more particularly to a liquefied gas pump device for storing a liquefied gas such as liquefied natural gas.

[0002]

2. Description of the Related Art As a liquefied gas pump device for transporting a liquefied gas such as liquefied natural gas, there is, for example, a submerged pump device for a liquefied gas tank with a built-in tank used in a liquefied gas tank. In the gas pump device,
Conventionally, for example, as disclosed in Japanese Patent Application Laid-Open No. 8-296586, a hydrostatic bearing and an auxiliary double-row ball bearing are employed.

Here, such a conventional liquefied gas pump device will be described with reference to FIG. 19, taking a liquefied gas tank submerged pump device as an example.

[0004] 1 is a liquefied gas tank, 1 A is a ceiling plate of the gas tank 1, and 2 is a liquid pumping pipe suspended in the liquefied gas tank 1. A suction valve 3 is attached to a lower end of a liquid pumping pipe 2 suspended in the liquefied gas tank 1, and a submerged pump main body 5 for the liquefied gas tank is mounted on a seat surface 4 of the liquid pumping pipe 2. Reference numeral 6 denotes a plurality of discharge ports provided on the outer periphery of the submerged pump main body 5.
A head plate 7 provided with a pump lifting mechanism is provided at the top of the liquid pumping tube 2, reference numeral 8 denotes a lifting wire, reference numeral 9 denotes a power supply cable, and reference numeral 10 denotes a hoist.

The submerged pump main body 5 for the liquefied gas tank includes the head plate 7 inside the pumping pipe 2 vertically suspended from the ceiling plate 1A of the liquefied gas tank 1.
From the lifting wire 8 to a depth of 5
It is suspended to about 0 m, and is seated on the seating surface 4 below the pumping pipe 2 and installed.

Power is supplied to the liquefied gas tank submerged pump main body 5 by a power supply cable 9. When the operation of the pump is started, the liquefied gas is supplied to the suction valve 3.
Then, the pressure is increased and discharged from the pump discharge port 6, and ascends in the liquid pumping pipe 2 and is sent out to the discharge pipe 11 as shown by an arrow in the figure.

Next, an example of a conventional liquefied gas pump main body will be described with reference to a liquefied gas tank submerged pump main body diagram shown in FIG.

The submerged pump body 5 for a liquefied gas tank has a structure in which an inducer 5B, a plurality of impellers 5C, and a submerged motor rotor 5D attached to a pump rotating shaft 5A for improving suction performance are fixed. It has an integral structure, and rotates integrally.
The pump rotating shaft 5A, the inducer 5B, the plurality of impellers 5C, and the submerged motor rotor 5D have self-liquid lubricated hydrostatic bearings having a long bearing life and excellent vibration damping properties (the upper hydrostatic bearing 5E, Medium hydrostatic bearing 5F, lower hydrostatic bearing 5G)
Are supported in the radial direction. The upper hydrostatic bearing 5E and the middle hydrostatic bearing 5F have ball bearings (upper ball bearing 5H, middle ball bearing 5I) as auxiliary bearings when the pump is started and stopped.
1) is provided.

When the pump is in a normal operation state (a state in which the pumping pipe 2 is filled with the pump discharge liquid), the ball bearings 5H, 5H
An axial thrust balance device 5M comprising a balance disk or the like as disclosed in Japanese Patent Publication No. 61-5558, for example, so that the hydrostatic bearings 5E, 5F and 5G work in place of I1.
Is configured. Thus, in the normal operation state of the pump, the function of the shaft thrust balancing device 5M causes the pump rotating shaft 5A to move in the axial direction, and the middle ball bearing 5I1 to the housing 5
The thrust load applied to the middle ball bearing 5I1 after floating away from L is zero. However, when the pump 5 is started, for several minutes until the inside of the liquid pumping tube 2 is filled with the discharge liquid,
The pump 5 is operated at a discharge pressure considerably lower than a predetermined discharge pressure. This is because only a small discharge pressure for pushing up the liquid is sufficient for these several minutes. For this reason, the axial thrust balance device 5M does not function, and a large thrust load such as the weight of the pump rotating body and the downward thrust of the impeller 5C is applied to the middle ball bearing 5I1. In particular, when the diameter of the pumping pipe 2 is increased due to an increase in the capacity of the pump or the like, the time required from the start of the pump 5 until the liquid fills the pumping pipe 2 is further extended. The time during which the thrust load is applied to the middle ball bearing 5I1 also increases, and the middle ball bearing 5I1
1 is also shortened. In order to cope with this, conventionally, a double row ball bearing 5I1 in which a single row ball bearing disclosed in Japanese Patent Application Laid-Open No. 8-296586 is arranged in a double row is mounted on a middle ball bearing 5I1.
(Hereinafter referred to as double-row ball bearings) to reduce the load applied to each ball bearing. Further, as described in Japanese Patent Application No. 8-139864, the double row ball bearing 5I1 has a ring spacer 5J interposed between the double row ball bearings, and a ball bearing outer ring or inner ring is fixed by a retainer 5K. (FIG. 20 shows an example in which the outer ring is fixed), and integrated to ensure equal distribution of the load to each ball bearing of the double row ball bearing.
When the outer ring is fixed by the retainer 5K, the inner ring is fixed to the rotating shaft 5A, and when the inner ring is fixed, the outer ring is fixed to the housing 5L. FIG.
Is the former. In addition, for several minutes at the time of the start-up, since the discharge pressure of the pump 5 is small, the static pressure bearings 5E, 5F,
The bearing effect of G is small, and the rotating shaft 5A swings around the gap between the hydrostatic bearing and the rotating shaft. When these conditions are combined, taking the case of fixing the double-row ball bearing inner ring to the rotary shaft 5A as an example, as shown in FIG. 21, the rotary shaft 5A has the lower seating surface of the double-row ball bearing retainer 5K. Perform a precession that swings around as a fulcrum. In this precession state, the lower seating surface of the retainer 5K does not sit on the entire surface but sits in a state of point contact, and receives a large thrust load in a state where the rotating shaft is inclined. A stable load is applied, the wear of the double row ball bearing 5I increases, and the bearing life is shortened. Even if the entire surface is in contact with the seating surface of the lower surface of the retainer 5K, the angular clearance is small in the double row ball bearing, and the precession movement of the shaft causes unstable behavior of the ball of the ball bearing, thereby increasing wear. In order to cope with this, the cushioning material or the cushioning structure disclosed in Japanese Patent Application Laid-Open Nos. 9-212927 and 9-356671 is replaced with a retainer 5K.
And the rotation shaft 5A, between the retainer 5K and the housing 5L, etc., so that even if the precession occurs, the cushioning material or the cushioning structure follows the inclination. Abnormal wear of the bearing is prevented.

[0010]

The bearing portion of the conventional submerged pump device for a liquefied gas tank has been designed to cope with a thrust load. However, when the size of the pump is increased, the thrust load and the load time are both increased. Will increase. In this case, a more reliable pump device bearing that can cope with a more severe load condition is required.

An object of the present invention is to provide a pump device in which the number of ball bearings in the pump device bearing portion is increased to reduce the load applied per bearing.

Another object of the present invention is to provide a pump device having a simplified structure by reducing the number of parts of the pump device bearing.

Further, an object of the present invention is to provide a buffer member and a buffer structure in the bearing portion even when the number of arranged ball bearings is increased and the structure is simplified as described above, so that the life of the pump device can be improved. An object of the present invention is to provide a pump device capable of preventing abnormal wear or the like due to differential movement.

[0014]

SUMMARY OF THE INVENTION The object of the present invention is to provide a pump shaft for sucking and discharging liquefied gas, a drive unit for rotating the pump shaft, and a position along the pump shaft below the drive unit. An impeller that pressurizes the sucked liquefied gas,
Achieved by arranging a plurality of single-row bearings in the bearing portion of the pump body in a liquefied gas pump device having a discharge hole for discharging liquefied gas pressurized by an impeller, a bearing for supporting a pump shaft, and the like. Is done.

In the liquefied gas pump device, when the pump is started, the liquefied gas fills the liquid pumping pipe and reaches a predetermined discharge pressure, and the thrust load applied to the bearing for several minutes until the thrust equilibrium device operates. The load applied to each ball bearing can be reduced, and the life of the bearing can be prolonged and the reliability can be improved.

Further, in the present invention, the ring spacer 5J, the retainer 5K, etc. of the pump device bearing are eliminated, and the number of parts is reduced and the structure is simplified.

According to the present invention, by simplifying the structure, it is possible to improve the reliability of the bearing portion and reduce the cost.

Further, in the present invention, in a state where the number of ball bearings in the pump device bearing portion is increased and the structure is simplified, a cushioning material and a buffer structure are installed in the pump device bearing portion. According to the present invention, even if the number of ball bearings arranged in the pump device bearing portion is increased or the structure is simplified, when precession due to whirling of the pump rotating shaft occurs,
The cushioning material follows the inclination of the shaft, thereby preventing abnormal wear and the like of the ball bearing and further improving the reliability with respect to the long life of the bearing.

[0019]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows an embodiment of the present invention.
FIG. 9 is a sectional view of a pump body when the present invention is applied to the liquefied gas tank submerged pump device described in FIG. FIG. 2 is an enlarged view of the middle bearing portion of the pump body shown in FIG. 1. FIGS. 3 to 18 show various embodiments of the present invention, as shown in FIGS. It is sectional drawing of the middle bearing part of a pump at the time of applying this invention to a pump apparatus. In the figure, those having the same reference numerals as those in FIGS. 19 and 20 are the same parts as those in the prior art and are not shown in FIG. 1, but it can be said that a liquefied gas tank, a discharge pipe and the like exist as in FIG. Not even.

FIG. 1 shows a submersible pump device for a liquefied gas tank according to the present embodiment, which includes a pumping pipe 2 suspended in a liquefied gas tank and a pump body 5 mounted on a bottom seating surface 4 of the pumping pipe 2.
Consists of A suction valve 3 is attached to the bottom of the pumping tube, and liquefied gas is sucked in from the suction valve 3 and discharged into the solution pipe 2 from a plurality of discharge ports 6 provided on the outer periphery of the pump body 5. The structure of the pump body 5 is a pump rotating shaft 5A.
In addition, an inducer 5B, a plurality of impellers 5C, and a submerged motor rotor 5D are fixed, and they have an integral structure and rotate integrally. The pump rotating shaft 5A is self-liquid lubricated hydrostatic bearings (upper hydrostatic bearing 5E, middle hydrostatic bearing 5F, lower hydrostatic bearing 5G).
Are supported in the radial direction. The upper hydrostatic bearing 5E and the middle hydrostatic bearing 5F have ball bearings (upper ball bearing 5H, middle ball bearing 5I) as auxiliary bearings when the pump is started and stopped.
2) is provided. An enlarged view of the vicinity of the middle bearing is shown in FIG.

The inner ring of the middle ball bearing 5I2 is
A, when the pump is in a normal operation state, the pump rotating shaft 5 is driven by the shaft thrust balancing device 5M.
The free movement of A in the axial direction causes the middle ball bearing 5I2 to separate (float) from the housing 5L, and the thrust load applied to the middle ball bearing 5I2 becomes zero. However, when the pump 5 is started, the pump 5 is operated at a discharge pressure considerably lower than a predetermined discharge pressure for several minutes until the inside of the liquid pumping tube 2 is filled with the discharge liquid. Does not function, and a large thrust load such as the weight of the pump rotating body and the downward thrust of the impeller 5C is applied to the middle ball bearing 5I2. Also, for several minutes when the pump is started, the rotating shaft 5A
Performs a precession such as swinging around the middle bearing portion as shown in FIG.

An embodiment in such a pump structure will be described.

FIG. 2 shows ball bearings arranged in a plurality of rows. This bearing is composed of a plurality of rows of ball bearings.
Thrust load applied per unit can be distributed.

In the conventional immersion pump device for a liquefied gas tank, the pressure is considerably lower than a predetermined discharge pressure for a few minutes after the pump is started until the pumping pipe becomes full, so that the thrust load is reduced to zero. The balancing device did not function properly, and a thrust load was applied to the ball bearing. Therefore, when the diameter of the pumping tube becomes large, the filling state of the pumping tube becomes longer, the time during which the thrust load is applied is extended, and the bearing life is significantly shortened. Was. On the other hand, a method of dispersing the thrust load by arranging the ball bearings in double rows has been adopted. However, the present invention further increases the number of rows of the ball bearings to thereby increase the thrust load applied to one ball bearing. , And can contribute to further prevention of reduction in bearing life and improvement in reliability.
In addition, FIG. 2 fixes the inner race of the middle ball bearing 5I2 to the rotating shaft 5A,
Although this is an example in which the outer ring is fixed by the retainer 5K, in the present invention, the outer ring is fixed to the housing 5L, and the inner ring is fixed to the retainer 5K.
The method of fixing with K is also applicable. Further, the inner race of the middle ball bearing 5I2 may be manufactured integrally with the rotating shaft 5A, and the outer race may be fixed by the retainer 5K. The outer race of the middle ball bearing 5I2 may be manufactured integrally with the housing 5L, and the inner race may be formed of the retainer 5K. May be fixed. The present invention is also applicable to these methods.

Next, FIG. 3 shows that a plurality of ball bearing outer rings and inner rings are integrated to form a ring spacer 5J and a retainer 5K for fixing the outer ring or the inner ring which have conventionally been interposed between the bearings. This is an example in which the structure is eliminated and the structure is simplified. This integrated ball bearing may be used with the outer ring fixed to the housing or the inner ring fixed to the shaft. Further, the outer ring may be manufactured integrally with the housing, or the inner ring may be manufactured integrally with the shaft.

Next, FIG. 4 shows that a plurality of ball bearing outer rings are integrated and a plurality of rows of ball bearing inner rings are arranged.
This is an example in which a ring spacer 5J conventionally interposed between bearings and a retainer 5K fixing an inner ring are eliminated to simplify the structure. The integrated ball bearing outer ring may be used by being fixed to the housing, or may be manufactured integrally with the housing.

Next, FIG. 5 shows that a plurality of ball bearing inner rings are integrated and a plurality of rows of ball bearing outer rings are arranged.
This is an example in which a ring spacer 5J conventionally interposed between bearings and a retainer 5K fixing an outer ring are eliminated to simplify the structure. The integrated ball bearing inner ring may be used by being fixed to a shaft, or may be manufactured integrally with the shaft.

Incidentally, the present invention may be partially implemented and shared with a ring spacer, a retainer and the like.

According to the present invention, the number of parts is reduced and the structure is simplified by using a method such as integrating ball bearings.
This can contribute to cost reduction and improvement of the reliability of the bearing portion.

When these ball bearings are arranged in a plurality of rows, even when the structure is simplified, the use of a buffer material or a buffer structure effectively allows the precession of the rotary shaft 5A to occur when the pump is started. An increase in bearing wear can be prevented.

FIG. 6 shows the seating surfaces of the retainers 5K of the ball bearings arranged in a plurality of rows when the inner ring of the ball bearing 5I2 is fixedly mounted on the rotating shaft 5A, and the mating housing seating of the retainer. FIG. 7 shows, in the case where the outer ring of the ball bearing 5I2 is fixedly installed in the housing 5L, between the bearing surface and the bearing surface, the retainer of the rotating shaft 5A and the ball bearing retainers arranged in a plurality of rows on which the rotating shaft is seated. This is an example in which a disc spring 12A is provided as a cushioning material between a 5K seating surface. As a result, even when the precession of the pump rotating shaft occurs, the disc spring 12A bends to follow the inclination of the pump rotating shaft 5A by the deflection, thereby buffering the precession, and to the multi-row ball bearing during the precession. It is possible to reduce the unstable load to be applied, and prevent abnormal wear and the like of the multi-row ball bearing. The disc spring 12A may be fastened to the rotating shaft 5A, the retainer 5K, the housing 5L, or the like by a screw or the like, or may be integrated with the rotating shaft 5A, the retainer 5K, the housing 5L, or the like.

In the present invention, when the inner race of the multi-row ball bearing 5I2 is fixed to the rotating shaft 5A as shown in FIG. 6, the outer race of the multi-row ball bearing 5I2 is connected to the housing 5L as shown in FIG.
The method can be applied to both methods when fixed to.

Next, FIG. 8 shows that the outer ring and the inner ring of the ball bearing are integrated as described above, so that the ring spacer 5J, the outer ring or the inner ring, which has conventionally been interposed between the bearings, is fixed to the retainer 5K. This is an example in which a cushioning material is applied in a state where the structure is simplified and the structure is simplified. With this configuration, the same effect as the above-described cushioning material can be obtained. Also in this case, when the inner race of the multi-row ball bearing 5I2 is fixed to the rotating shaft 5A, the multi-row ball bearing 5I2
Can be applied to either method when the outer ring is fixed to the housing 5L. FIG. 8 shows the former, which is a ball bearing 5I2.
A disc spring 12A is provided between a seating surface and a housing 5L seating surface on which the ball bearing 5I2 is seated. In the latter,
Rotary shaft 5A seating surface and ball bearing 5I on which rotary shaft 5A is seated
A disc spring 12A may be provided between the two seating surfaces. In this case, also in this case, the disc spring 12A includes the rotating shaft 5A, the ball bearing 5I2,
It may be fastened to the housing 5L or the like by screws or the like, or may be integrated with the rotating shaft 5A, the ball bearing 5I2, the housing 5L or the like.

Next, as shown in FIG. 9, a plurality of ball bearing inner rings are integrated as described above, and the ball bearing outer rings themselves are arranged in a plurality of rows.
J is an example in which the cushioning material is applied in a state where the retainer 5K to which the outer ring is fixed is eliminated and the structure is simplified. With this configuration, the same effect as the above-described cushioning material can be obtained. Incidentally, also in this case, the disc spring 12A is
It may be fastened to the ball bearing 5I2, the housing 5L, etc. by screws or the like, or may be integrated with the ball bearing 5I2, the housing 5L, etc.

Next, as shown in FIG. 10, a plurality of ball bearing outer rings are integrated as described above, and a plurality of rows of ball bearing inner rings are arranged. This is an example in which the retainer 5 </ b> K, which has been fixed, is removed, and the cushioning material is applied in a state where the structure is simplified.
With this configuration, the same effect as the above-described cushioning material can be obtained. In this case, the disc spring 12A is also used.
May be fastened to the rotating shaft 5A, the ball bearing 5I2, etc. by screws or the like, or may be integrated with the rotating shaft 5A, the ball bearing 5I2, etc.

FIGS. 6 to 1 show the cushioning material of the present invention.
In addition to the disc spring 12A shown in FIG. FIG.
Reference numeral 1 denotes an example in which a coil spring 12B is used as a cushioning material, in which a plurality of coil springs are interposed between two ring plates. The coil spring has one coil surrounding the entire circumference of the ring plate. May be used. Further, similarly to the case of the disc spring 12A, the seating surfaces may be fastened by the coil spring 12B, or may be an integral structure.

Next, FIG. 12 shows an example in which a leaf spring 12C is used as a cushioning material, and the leaf spring 12C shown in FIG.
Has a plurality of cuts and projections 13 formed in the circumferential direction of the leaf spring 12C in order to improve the followability with the retainer 5K and the ball bearing, etc. Is provided. The protrusion 13 may be provided on a ball bearing or the like as shown in FIG. In addition, as shown in FIGS. 12 and 13, the ball bearing 5I2 is provided with the L-shaped projection 14 on the inner side of the seating surface with the leaf spring 12C. Foreign matter and the like can be prevented from entering the inside of the ball bearing 5I2. The method of providing the L-shaped projections 14 on the inner side of the seating surface is based on the disc spring 12A and the coil spring 12A.
Naturally, it can be applied to the case B. Regarding the shape of the leaf spring, in addition to the shapes shown in FIGS.
The shape shown in FIG. Leaf spring 12 shown in FIG.
In C, a plurality of grooves are provided on the lower surface of the leaf spring to reduce the thickness of the plate in order to deflect the plate, and a retainer 5K, a ball bearing, and the like are provided on the upper surface of the thin portion of the plate. Are provided in the circumferential direction of the leaf spring 12C. The leaf spring 12C may have other shapes, but any shape may be used as long as it is a leaf spring as shown in FIGS. Further, the leaf spring 12C may fasten between seating surfaces similarly to the disc spring 12A and the coil spring 12B, or may have an integral structure. As an example, FIGS. 15 and 16 are conceptual diagrams of a method of attaching the leaf spring 12C. FIG. 15 shows an example in which the leaf spring 12C is formed integrally with the housing 5L. The leaf spring 12C may be formed on the housing 5L from the beginning. FIG. 16 shows an example in which the leaf spring 12C is fastened to the housing 5L with bolts or the like. The method shown in FIG. 16 is a case in which the housing 5L is divided and fastened with the leaf spring 12C interposed therebetween. According to the method of fastening the leaf spring 12C as shown in FIG. 16, the leaf spring 12C can be easily replaced. As described above, there is a method of providing various springs as a cushioning material. However, for example, a combination may be used in which a coil spring 12B is interposed on the lower surface of a leaf spring 12C.

In addition to the method using a spring as a cushioning material, there is also a method using a cushioning structure between the seating surfaces. As an example, in FIG. 17, by integrating a plurality of ball bearing outer rings and inner rings, a ring spacer 5J conventionally interposed between the bearings, a retainer 5K fixing the outer ring or the inner ring is eliminated, and the structure is reduced. An example in which a buffer structure is applied to a simplified state will be described. In FIG. 17, each seating surface has a spherical seat cushioning structure formed by an appropriate circular arc cross section. Even when the pump rotating shaft 5A is slightly inclined due to precession, FIG.
By adopting an appropriate spherical seat structure so that the seated portion does not come into point contact and seats on the entire surface, followability to precession motion can be ensured, and the load on the ball bearing during precession motion can be secured. This can reduce the unstable load that is caused and prevent abnormal wear of the ball bearing. What is shown in FIG.
This is a case where a ring-shaped component 15 with a spherical seat attached so that the spherical seat cushioning structure can be replaced is fastened to the housing 5L with a screw or the like. By doing so, the material of the housing 5L can be changed in addition to the replacement of the spherical seat cushioning structure. The wear resistance can be improved by using a material having excellent slidability, such as special carbon, as the material of the ring-shaped component 15 having the spherical seat. Although not shown, the ring-shaped component 15 with the spherical seat may be attached to the ball bearing 5K. It is to be noted that the method of applying the cushioning structure can be applied to either the method of fixing the inner ring of the multi-row ball bearing 5I2 to the rotating shaft 5A or the method of fixing the outer ring of the multi-row ball bearing 5I2 to the housing 5L. is there. In the present embodiment, the former has been described as an example, but also in the latter, the rotating shaft, the seating surface of the ball bearing has a buffer structure,
Alternatively, the same effect can be obtained by installing a buffer structure on the seating surfaces of the rotating shaft and the ball bearing. In addition, the application of this buffer structure integrates the plurality of ball bearing outer rings described above,
A method of arranging the ball bearing inner ring itself in a plurality of rows, a method of integrating a plurality of ball bearing inner rings and arranging the ball bearing outer ring itself in a plurality of rows,
It is also applicable to a method using a retainer or a ring spacer.

Although the present invention has been described in detail, the present invention can naturally be applied to other types of liquefied gas pump devices. Further, the present invention is effective not only for a liquefied gas but also for a pump handling a low-temperature liquid or the like.

[0041]

According to the present invention, by arranging a plurality of rows of ball bearings, it is possible to suppress a reduction in bearing life due to a thrust load generated when the pump is started and stopped, and to improve reliability.

Further, according to the present invention, by reducing the number of bearing parts, it is possible to reduce costs and improve reliability.

Thus, a long-term stable operation of the liquefied gas pump device can be achieved.

Further, according to the present invention, even if the number of ball bearings in the pump device bearing portion is increased or the structure is simplified, even if precession due to whirling of the pump rotating shaft occurs. , The cushioning material and the buffer structure follow the inclination of the shaft,
As a result, abnormal wear and the like of the ball bearings arranged in a plurality of rows can be prevented, and the reliability of the bearing for a long service life can be further improved.

[Brief description of the drawings]

FIG. 1 is a sectional view of a liquefied gas pump according to an embodiment of the present invention.

FIG. 2 is an enlarged view of a bearing part in a pump showing an embodiment of the present invention.

FIG. 3 is an enlarged view of a bearing part in a pump showing another embodiment of the present invention.

FIG. 4 is an enlarged view of a bearing part in a pump showing still another embodiment of the present invention.

FIG. 5 is an enlarged view of a bearing part in a pump showing still another embodiment of the present invention.

FIG. 6 is an enlarged view of a bearing part in a pump showing still another embodiment of the present invention.

FIG. 7 is an enlarged view of a bearing part in a pump showing still another embodiment of the present invention.

FIG. 8 is an enlarged view of a bearing part in a pump showing still another embodiment of the present invention.

FIG. 9 is an enlarged view of a bearing part in a pump showing still another embodiment of the present invention.

FIG. 10 is an enlarged view of a bearing part in a pump showing still another embodiment of the present invention.

FIG. 11 is an enlarged view of a bearing part in a pump showing still another embodiment of the present invention.

FIG. 12 is an enlarged view of a bearing part in a pump showing still another embodiment of the present invention.

FIG. 13 is an enlarged view of a bearing part in a pump showing still another embodiment of the present invention.

FIG. 14 is a view of a leaf spring showing an embodiment of the present invention.

FIG. 15 is an enlarged view of a bearing part in a pump showing still another embodiment of the present invention.

FIG. 16 is an enlarged view of a bearing part in a pump showing still another embodiment of the present invention.

FIG. 17 is an enlarged view of a bearing part in a pump showing still another embodiment of the present invention.

FIG. 18 is an enlarged view of a bearing part in a pump showing still another embodiment of the present invention.

FIG. 19 is an overall view of a submerged pump device for a liquefied gas tank.

FIG. 20 is a sectional view of a conventional submerged pump main body for a liquefied gas tank.

FIG. 21 is an explanatory diagram of a precession motion of a pump rotation shaft.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Liquefied gas tank 1A Tank ceiling plate 2 Lifting pipe 3 Suction valve 4 Seat surface 5 Liquefied gas pump main body 5A Rotating shaft 5B Inducer 5C Impeller 5D Submerged motor rotor 5E Upper static pressure bearing 5F Medium static pressure bearing 5G Lower static pressure Bearing 5H Upper auxiliary ball bearing 5I1 Middle auxiliary ball bearing (double row ball bearing) 5I2 Middle auxiliary ball bearing (multiple row ball bearing) 5J Ring spacer 5K Retainer 5L Housing 5M Shaft thrust balance device 6 Pump outlet 7 Head plate 8 Lifting wire 9 Feeding cable 10 Winding machine 11 Discharge tube 12A Disc spring 12B Coil spring 12C Leaf spring 13 Projection or convex shape 14 L-shaped portion 15 Spherical seat part

Claims (9)

[Claims] 1. A pump shaft, a drive unit for rotating and driving the pump shaft, an impeller provided at a position below the drive unit along the pump shaft for increasing the pressure of the sucked liquefied gas, and a booster for the impeller. In the liquefied gas pump device having a discharge hole for discharging the liquefied gas and a bearing for supporting the pump shaft,
A liquefied gas pump device, wherein a plurality of single-row bearings are arranged in the bearing portion of the pump body. 2. A liquefied gas pump device according to claim 1, wherein an outer ring and an inner ring of a plurality of ball bearings are integrated and arranged in said bearing portion. 3. The liquefied gas pump device according to claim 1, wherein an outer ring of a plurality of ball bearings is integrated with the bearing portion, and a plurality of rows of bearing inner rings are arranged. 4. The liquefied gas pump device according to claim 1, wherein a plurality of ball bearing inner rings are integrated with the bearing portion,
A liquefied gas pump device comprising a plurality of rows of bearing outer rings. 5. The liquefied gas pump device according to claim 1, wherein a cushioning material or a cushioning structure is interposed between a pump shaft of the bearing portion, a retainer, a ball bearing, and a seating surface of the housing. A liquefied gas pump device characterized by the above-mentioned. 6. A liquefied gas pump device according to claim 5, wherein said buffer material or buffer structure is formed integrally with a pump shaft, a retainer, a ball bearing, and a housing. . 7. A liquefied gas pump device according to claim 5, wherein said cushioning material and said buffer structure are fixed to a pump shaft, a retainer, a ball bearing, and a housing. 8. A liquefied gas pump device according to claim 5, wherein said cushioning member is any one of a disc spring, a coil spring and a leaf spring. . 9. The liquefied gas pump device according to claim 1, wherein the pump shaft of the bearing portion, the retainer, the ball bearing, and the housing have a spherical seat formed by an arcuate cross section. A liquefied gas pump device, comprising: