JPH09317677A - Vertical shaft type submerged pump device for liquefied gas tank - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure the uniform distributivity of a thrust load, by arranging a plurality raw of deep groove ball bearings, in a plurality of bearings for supporting a pump shaft and an intermediate bearing in the vicinity of a balance disk which is attached on the pump shaft and balances driving force, and fixing the outer or inner rings of the ball bearings by a retainer. SOLUTION: The inner side of a retainer 20 is machined peripheries of outer rings of deep groove ball bearings arranged in plural rows in an appropriate fitting tolerance and at coaxiality. A seat surface in such an extent that the rivets of the ball bearings may not be brought into contact therewith, is arranged on a contact side in the axial direction of a bearing housing. A projection is arranged on the upper part of the retainer 20 so as to prevent axial slippage, and fixed by shrinkage-fitting when the ball bearings are inserted therein. By the arrangement of the retainer 20, occurrence of each of independent play of the outer ring races of the upper and lower two-raw deep groove type ball bearings can be prevented, and balance is kept so that the contact angles of the outer ring races and balls are equalized. Hereby, thrust loads can be equally distributed to the upper and lower deep groove ball bearings.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vertical shaft type submersible pump device for a liquefied gas tank.

[0002]

2. Description of the Related Art A conventional submerged pump device for a liquefied gas tank disclosed in Japanese Patent Laid-Open No. 1-301990 is shown in FIG.
Shown in In the liquefied gas tank 1, a pumping pipe 2 is vertically formed so as to hang down. The submersible pump 5 is inserted and installed inside the pumping pipe 2 from the outside. For this, the submersible pump 5 is vertically suspended from the head plate 8 by the wire 4 (height: several tens of meters), the wire 4 is lowered, and the seat surface 6 at the bottom of the pumping pipe 2 is lowered.
The submersible pump 5 is seated on. The submersible pump 5 is composed of an impeller (impeller) section 5B for increasing the pressure and a rotary drive section (motor) 5A that is connected to the shaft of the pump and rotates the shaft. The seat surface 6 communicates with the suction port 3, and the submersible pump 5
Is boosted by the liquefied gas submersion pump 5 from the suction valve 3A,
A plurality of discharge holes 5P provided on the discharge side of the impeller portion 5B
From the nozzle. The discharged liquefied gas flows out of the discharge hole 5P, flows upward in the solution pipe 2, and is discharged from the discharge pipe 7.

When the submersible pump 5 is started, the submerged pump 5 is kept for a few minutes until the pumping liquid 2 is filled with the discharge liquid.
Is operated at a large flow rate at a discharge pressure considerably lower than a predetermined discharge pressure.

An example of a general submerged pump for a liquefied gas tank other than that shown in FIG. 8 is disclosed in Japanese Patent Publication No. 61-5558. In such a submersible pump, a ball bearing (for example, a single-row deep groove type ball bearing) and a hydrostatic bearing that support the rotating shaft are provided near the position where the rotary drive unit 5B is arranged and the position where the impeller 5A is arranged. Further, an axial thrust balancer including a balance disk is provided to reduce the thrust load applied to the ball bearings to zero during pump operation. Therefore, only the radial load is applied to the ball bearing during the normal operation of the pump, but since the radial load is received by the hydrostatic bearing, the ball bearing essentially plays an auxiliary role. However, since the axial thrust balancer functions when the pump is generating a predetermined discharge pressure, the ball bearing has a weight of the pump rotor and a downward thrust of the impeller for several minutes until the discharge liquid fills the pumping pipe. That is, a large thrust load is applied.

Further details will be described with reference to FIG. FIG. 7 shows a system head curve immediately after the liquefied gas tank submersion pump 5 is started. In the curve on the left side, the horizontal axis shows the discharge flow rate and the vertical axis shows the discharge output.
,,, and are changing. The pressurized liquefied gas is discharged from the discharge pipe 7 after about 3 minutes. The pump device on the right side shows an example including a pumping pipe 2, a pump 5, a head plate 8 and a discharge pipe 7.

First, when the pump 5 is started, a slight discharge pressure sufficient to push up the liquid is enough for several minutes until the discharge liquid fills the inside of the pumping pipe 2, and the pump 5 is considerably lower than the rated discharge pressure. It operates at the discharge pressure and operates in a large liquid volume. At the same time as the liquid level in the pumping pipe 2 gradually rises, the system head curve of the pump also changes.
The discharge pressure reaches the rated value only when the discharge pressure is satisfied by the upper discharge pipe 20.

Especially when the pump becomes large and the pumping pipe 2 has a large diameter, the time is further extended until the discharge pressure reaches the rated value, the axial thrust balancing device does not operate, and a large thrust load is applied to the ball bearing. Will be loaded.

When the pump is small and the pump has a small diameter, the liquid filling time is short and the thrust balancer works in a relatively short time. However, due to the increase in the capacity of the pump, the diameter of the pump is increased. If it is made, the time required for the liquid to fill the pumping pipe after the pump is started will be further extended, and the time that thrust load will be applied to the ball bearing will be prolonged accordingly, and the bearing life will be shortened significantly. Therefore, it was not possible to expect long-term stable operation of the pump. In order to solve such a problem, there is one described in Japanese Patent Laid-Open No. 7-102285. However, in the present invention, a single row deep groove ball bearing is arranged in multiple rows, and a thrust load is distributed to a plurality of single row deep groove type bearings. The purpose is to reduce the load on each deep groove ball bearing and extend the life of the bearing.

[0009]

The single-row deep groove type ball bearing arranged in double rows is fixed to the pump rotating shaft, but in addition to that, the deviation of double row arrangement is prevented and the thrust load is evenly applied. There were no fixtures. In the first place, ball bearings generally have a slight clearance between the ball and the race (inner and outer rings). For example, when the inner ring race is fixed to the shaft, the outer ring race is in the axial and circumferential directions. There is looseness and deviation occurs. or,
When the ball is worn, the backlash becomes larger.

The deep groove type ball bearings arranged in double rows are, for example, 2
When arranged in rows, when the contact angles of the ball and the race of the deep groove type ball bearing are equal in both the upper deep groove type ball bearing and the lower deep groove type ball bearing, the effect of evenly distributing the thrust load is exhibited.
When the axial thrust balancer operates or the behavior of the shaft causes the rotating system including the deep groove type ball bearings arranged in double rows to move axially and the ball bearings have backlash as described above, for example, the inner ring side Even if the upper and lower deep groove ball bearings are fixed to the shaft in parallel, the outer rings of the upper and lower deep groove ball bearings are prevented because there is no one that prevents them from being separated from the ring spacer and fixes the outer ring side in parallel. It becomes easy to generate backlash independently. At that time, the outer ring and ring space of the upper and lower deep groove type ball bearings
There is a gap between the sac and foreign matter in the liquefied gas gets in,
If a thrust load is applied in that state, the contact angle between the ball and the race may not be the same in both the upper deep groove ball bearings and the lower deep groove ball bearings. It will damage.

Further, although the static pressure bearing and the axial thrust parallel device do not significantly increase the wear of the ball and the ball of the ball bearing, the wear increases and the backlash of the outer ring race increases. In this case, it is necessary to prevent the ring spacer from coming off the outer race.

Further, when the outer rings of the deep groove type ball bearings arranged in double rows are fixed on the bearing housing side and the rotary shaft is movable in the axial direction, the wear of the ball bearings as described above becomes large. When the backlash of the inner ring race becomes large, it is necessary to prevent the ring spacer from coming off the inner race.

In a conventional single row deep groove type ball bearing having a double row arrangement in a submerged pump device for a liquefied gas tank, the thrust load should be firmly distributed to the upper and lower deep groove type ball bearings, and the thrust load should be uniformly distributed. Therefore, the reliability of the deep groove type ball bearing arranged in double rows must be improved.

It is an object of the present invention to improve the function and reliability of a deep groove type ball bearing arranged in a double row, and to extend the life of the bearing under the condition that the capacity of the pump is increased and the diameter of the pumping pipe is increased. It is an object of the present invention to provide a vertical shaft submersible pump device for a liquefied gas tank that makes it possible.

[0015]

The above-mentioned object is to insert a liquefied gas from a liquefied gas tank into a pumping pipe which is hung in a liquefied gas tank and suck and discharge the liquefied gas from the liquefied gas tank. A drive unit that rotationally drives the pump shaft, an impeller that is provided below the drive unit along the pump shaft, and that boosts the liquefied gas sucked from the liquefied gas tank, and discharges the liquefied gas that is boosted by the impeller. Discharge hole, multiple bearings that support the pump shaft, a balance disc that is attached to the pump shaft to balance the axial thrust, and a deep groove ball bearing that is arranged in double rows in the middle bearing provided near the balance disc. It is achieved by providing a retainer for fixing the outer ring or the inner ring of the deep groove type ball bearing arranged in double rows.

[0016]

1 is a vertical cross-sectional view of a vertical shaft type submersible pump device for a liquefied gas tank. In the figure, those having the same reference numerals as those in FIG.

The submerged pump device for a liquefied gas tank according to the present embodiment has a pumping pipe 2 suspended in the liquefied gas tank, and a pump 5 installed on the bottom surface of the pumping pipe 2 on a seat surface 6.
It consists of a casing 18.

The bottom portion 6 of the pumping pipe 2 is connected to the suction port 3, and the liquefied gas enters the pump 5 through the bottom portion 6 from the suction port 3 via the suction valve 3A.

The pump 5 comprises a rotary drive portion 5A provided at an upper position, an impeller portion 5B provided at a lower position, and a rotary shaft (shaft) 12. The rotary drive unit 5A includes a rotor (rotor) unit 9 coupled to the shaft 12 and a stationary (stator) unit 10 facing the rotor unit 9.
And the rotor unit 9 form a motor, and the shaft 12 is rotated by rotating the rotor unit 9.

The impeller portion 5B comprises a plurality of impellers 13 attached to the shaft 12 and a stage 11 attached to the fixed side from the liquefied gas suction side to above the shaft 12. Further, a plurality of discharge holes 5P are provided above the impeller portion 5B to send the pressurized liquefied gas to the discharge passage 5Q.

An upper bearing 16 is provided near the mounting position of the shaft 12 on the head cover 22 above the rotary drive unit 5A, and a lower bearing 1 is provided near the bottom 6 of the impeller 5B of the shaft 12.
4 is provided, and further, a middle bearing 15 is provided in the vicinity of a relay portion between the impeller portion 5B and the rotation driving portion 5A, and each supports the shaft 12. Besides this, the hydrostatic bearing 19A is provided above the upper bearing 16.
Is provided. A shaft thrust balancer 17 is provided around and below the middle bearing 15. The shaft thrust balancer 17 includes a cylindrical shaft sleeve 17A provided on the outer peripheral surface of the middle bearing 15,
It is composed of a static pressure bearing 19B, a balance disk 17B and the like.
When the pump is started, the middle bearing 15 supports the shaft 12. On the other hand, when the pump enters a normal operating state, the balance disk 17B is allowed to move in the axial direction so that the bearing housing 15A releases the support from the middle bearing 15. The thrust load acting on the middle bearing 15 is removed.

The upper bearing 16 uses a single row deep groove type ball bearing, and the middle bearing 15 uses a double row arrangement deep groove type ball bearing with a retainer attached to the outer ring side. The lower bearing 14 uses a hydrostatic slide bearing. The use of this hydrostatic plain bearing is
This is to support the end of the bearing.

The double-groove deep groove type ball bearing with the retainer attached used for the middle bearing 15 is, for example, the upper and lower two-row ball bearings, as can be seen from FIG. Form an important feature.

Hydrostatic bearings 19A, 19B are bearings 16, 1
5 is provided in the peripheral portion of the pump 5, and guides the high pressure discharge liquid of the pump to form a hydrostatic bearing.

FIG. 2 is a sectional view of an embodiment of a plurality of deep groove type ball bearings of the submerged pump device for a liquefied gas tank according to the present invention.

The inside of the retainer 20 is machined to the outer ring outer periphery of the double-groove deep groove ball bearing with proper fitting tolerance and coaxiality. The bearing housing 17A axial contact side is
Provide a bearing surface that does not hit the rivets of the ball bearing. A protrusion is provided on the upper portion of the retainer 20 in order to prevent axial displacement, and when the ball bearing is inserted, it is inserted and fixed on the principle of shrink fit.

FIG. 3 shows a sectional view of another embodiment of a plurality of arrays of deep groove type ball bearings of the submerged pump device for a liquefied gas tank according to the present invention.

The retainer 20 of the embodiment shown in FIG. 2 has no upper projection, and the ring plate 21 is used to fix the retainer body to the retainer main body with bolts, so that the retainer 20 is arranged in multiple rows. Fix the outer ring side of the deep groove ball bearing. It goes without saying that the axial height of the retainer main body in the axial direction of the inner peripheral portion is machined to have an appropriate size necessary for fixing in accordance with the height of the deep groove type ball bearing arranged in double rows.

According to the above-mentioned embodiment, by installing the retainer on the outer ring side of the double-groove deep groove type ball bearing, the upper and lower two rows of deep groove type ball bearing outer ring races are independently played. It is possible to maintain the parallelism so that the contact angles of the upper and lower rows of the deep groove type ball bearing outer ring and the ball are equalized. As a result, the thrust load is firmly distributed to the upper and lower deep groove type ball bearings, and it is possible to ensure that the thrust load is evenly distributed. In addition, it prevents the ring spacer on the outer ring from coming off due to unexpected behavior due to wear of the ball of the ball bearing, etc., and the function and reliability as a double-row deep groove ball bearing. It is possible to improve the sex.

Further, single row deep groove type ball bearings are arranged in multiple rows and integrally fixed to the shaft 12, and a structure is provided in which a gap is provided between the retainer 20 and the bearing housing 15d. Thrust balance balancer 17
It goes without saying that the ball bearings are smoothly moved, and thrust loads are not applied to the ball bearings, and radial loads are operated with almost no load due to the combination with the hydrostatic bearings, which ensures stable long-term operation of the pump. I can contribute.

In FIG. 4, the retainer for fixing the inner ring of the deep groove type ball bearing in the double row arrangement of the submerged pump device for a liquefied gas tank according to the present invention is arranged in the circumferential direction of the deep groove type ball bearing in the double row arrangement. It is fixed while maintaining a proper fit and coaxiality, and with respect to the axial direction, the upper end has a seat surface on which the protrusion of the pump rotating shaft rests, and the lower end has a deep groove type ball bearing arranged in double rows. This is an integrated structure that is fixed by providing a protrusion that can be inserted by cold fitting, and improves assembly workability.

In FIG. 5, the retainer for fixing the inner ring of the double-groove deep groove type ball bearing is fixed in the circumferential direction of the double-row arranged deep groove type ball bearing while maintaining a proper fit and coaxiality. In the axial direction, the upper end has a bearing surface on which the protrusion of the pump rotating shaft rests, and the lower end has a precision machined surface that matches the height of the deep groove ball bearings arranged in multiple rows. The ring-shaped plate that holds down the inner ring of the bearing is fixed with a screw fastening body to fix the inner ring of the deep groove type ball bearing that is arranged in multiple rows to form a split type structure, which does not require cold fitting work. Yes, it only requires machining.

[0033]

EFFECTS OF THE INVENTION By arranging the deep groove type ball bearings in a double row for the thrust load applied at the time of starting the pump of the vertical shaft type submerged pump device for the liquefied gas tank, the even load distribution is secured,
The function and reliability of the double row deep groove ball bearing are improved, and the long life of the bearing allows the pump to operate stably for a long period of time.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an embodiment of a submerged pump device for a liquefied gas tank according to the present invention.

FIG. 2 is a cross-sectional view of an embodiment of a double-row arrangement deep groove type ball bearing according to the present invention.

FIG. 3 is a cross-sectional view of an embodiment of a double-groove deep groove type ball bearing according to another example of the present invention.

FIG. 4 is a cross-sectional view of an embodiment of a double-row arrangement deep groove type ball bearing according to still another example of the present invention.

FIG. 5 is a cross-sectional view of an embodiment of a double-groove deep groove type ball bearing according to still another example of the present invention.

FIG. 6 is a schematic sectional view of a conventional submerged pump facility for a liquefied gas tank.

FIG. 7 is a system head curve immediately after starting the submersible pump for a liquefied gas tank.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Liquefied gas tank, 2 ... Pumping pipe, 3 ... Suction valve, 4 ... Suspension wire, 5 ... Submersion pump, 6 ... Seat surface, 7 ... Discharge pipe, 8 ... Head plate, 9 ... Motor rotor, 10 ... Motor stator, 11 ... Stage, 12 ... Pump shaft, 13
... impeller, 14 ... lower bearing, 15 ... middle bearing, 15a, 15
b ... single row arrangement deep groove type ball bearing, 15c ... ring spacer,
15f ... Ball, 15g ... Cage, 16 ... Upper bearing, 17
... Axial thrust balancer, 18 ... Casing, 19A, 1
9B ... Hydrostatic bearing, 20 ... Retainer, 21 ... Ring plate, F ... Load, θ ... Contact angle

Claims (5)

[Claims] 1. A submerged pump device for a liquefied gas tank, which is inserted into a lift pipe hung in a liquefied gas tank to suck and discharge a liquefied gas from the liquefied gas tank, and a drive for rotating and driving a pump shaft and the pump shaft. Section, an impeller that is provided below the drive unit along the pump shaft, and that boosts the liquefied gas sucked from the liquefied gas tank, a discharge hole that discharges the liquefied gas that is boosted by the impeller, and a pump shaft. It consists of multiple bearings to support, a balance disc mounted on the pump shaft to balance the axial thrust, and a deep groove type ball bearing arranged in double rows in the middle bearing provided near the balance disc. A vertical shaft type submersible pump device for a liquefied gas tank, characterized by comprising a retainer for fixing an outer ring or an inner ring of a deep groove type ball bearing. 2. The vertical shaft submersible pump device for a liquefied gas tank according to claim 1, wherein the retainer for fixing the outer ring of the double-groove deep groove ball bearing is arranged in the circumferential direction of the double-row deep groove ball bearing. , It is fixed in a state of maintaining a proper fit and coaxiality, and with respect to the axial direction, the lower end has a bearing surface on which the outer ring of the ball bearing rests, and the upper end has a deep groove type ball bearing arranged in double rows. A vertical shaft submersible pump device for a liquefied gas tank, which has an integral structure in which a protrusion that can be inserted by shrink-fitting is provided and fixed. 3. The vertical submersible pump device for a liquefied gas tank according to claim 1, wherein the retainer for fixing the outer ring of the deep groove type ball bearing arranged in double rows is arranged in the circumferential direction of the deep groove type ball bearing arranged in double rows. , It is fixed in a state of maintaining a proper fit and coaxiality, and in the axial direction, the lower end has a seating surface on which the outer ring of the ball bearing rests, and the upper end of the deep groove type ball bearing arranged in double rows. A split type structure that fixes the outer ring of the deep groove type ball bearing arranged in multiple rows by fixing the ring-shaped plate that has a precision processed surface that matches the height and suppresses the outer ring of the ball bearing with a screw fastening body. A vertical shaft type submersible pump device for a liquefied gas tank characterized by the above. 4. The vertical submersible pump device for a liquefied gas tank according to claim 1, wherein the retainer for fixing the inner ring of the deep groove type ball bearings arranged in the double row is arranged in the circumferential direction of the deep groove type ball bearings arranged in the double row. It is fixed in a state of maintaining proper fitting and coaxiality, and with respect to the axial direction, the upper end has a seat surface on which the protrusion of the pump rotating shaft rests, and the lower end has a deep groove type ball arranged in multiple rows. A vertical shaft submersible pump device for a liquefied gas tank, which has an integral structure in which a protrusion is inserted into a bearing so as to be inserted by being cold-fitted and fixed. 5. The vertical shaft submersible pump device for a liquefied gas tank according to claim 1, wherein the retainer for fixing the inner ring of the deep groove type ball bearing arranged in a double row is arranged in the circumferential direction of the deep groove type ball bearing arranged in a double row. , It is fixed in a state of maintaining a proper fit and coaxiality, and with respect to the axial direction, the upper end has a seat surface on which the protrusion of the pump rotating shaft rests, and the lower end has a double-row deep groove ball bearing. The split ring structure that fixes the inner ring of the double-groove deep groove ball bearings by fixing the ring-shaped plate that has a precision processed surface that matches the height of the The vertical shaft submersible pump device for liquefied gas tanks, characterized in that