JP3189683B2 - Vertical shaft submersible pump device for liquefied gas tank - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a vertical shaft submersible pump device for a liquefied gas tank.

[0002]

2. Description of the Related Art A conventional immersion pump device for a liquefied gas tank described in Japanese Patent Application Laid-Open No. 1-301990 is shown in FIG.
Shown in In the liquefied gas tank 1, a pumping pipe 2 is vertically formed vertically. A submersible pump 5 is inserted and installed inside the liquid pumping tube 2 from the outside. To this end, the immersion pump 5 is suspended vertically from the head plate 8 by the wire 4 (height: 10 m), the wire 4 is lowered, and the lower seating surface 6
The immersion pump 5 is seated. The submerged pump 5 includes an impeller (impeller) section 5B for increasing the pressure, and a rotary drive section (motor) 5A connected to the axis of the pump and rotating the axis. The seating surface 6 communicates with the suction port 3 and the submersible pump 5
Is pressurized by the liquefied gas immersion pump 5 from the suction valve 3A,
A plurality of discharge holes 5P provided on the discharge side of the impeller 5B
From the nozzle. The discharged liquefied gas flows upward through the solution pipe 2 through the discharge hole 5P, and is discharged from the discharge pipe 7.

When the submersible pump 5 is started, the submersible pump 5 is kept for several minutes until the liquid is filled in the liquid pumping tube 2.
Operates at a large flow rate at a discharge pressure considerably lower than a predetermined discharge pressure.

Another example of a general immersion pump for a liquefied gas tank other than that shown in FIG. 8 is that described in Japanese Patent Publication No. 61-5558. In such a submerged 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 between the position of the rotary drive unit 5B and the position of the impeller 5A. Further, there is provided an axial thrust balance device including a balance disk or the like for reducing the thrust load applied to the ball bearing to zero during operation of the pump. Therefore, during the normal operation of the pump, only the radial load is applied to the ball bearing. However, since the radial load is received by the hydrostatic bearing, the ball bearing substantially plays an auxiliary role. However, since the axial thrust balancer functions when the pump generates a predetermined discharge pressure, the ball bearing has a pump rotor weight and a downward thrust of the impeller for several minutes until the discharge liquid fills the pumping pipe. A large thrust load is applied.

A more detailed description will be given with reference to FIG. FIG. 7 shows a system head curve immediately after the liquefied gas tank submersible pump 5 is started. In the curve on the left side, the horizontal axis indicates the discharge flow rate, and the vertical axis indicates the discharge output.
,, And are changing. After about 3 minutes, the pressurized liquefied gas is discharged from the discharge pipe 7. The pump device on the right side shows an example composed of the liquid pumping tube 2, the pump 5, the head plate 8, and the discharge tube 7.

First, when the pump 5 is started, a slight discharge pressure sufficient to push up the liquid is sufficient for a few minutes until the liquid is filled in the liquid pumping pipe 2, and the pump 5 is considerably lower than the rated discharge pressure. The operation is performed at the discharge pressure, and the operation becomes a large liquid amount operation. The liquid level in the pumping pipe 2 gradually rises, and at the same time, the system head curve of the pump also changes.
Satisfies the conditions described above, and becomes the rated discharge pressure only after being throttled by the upper discharge pipe 20.

In particular, when the size of the pump becomes large and the pumping pipe 2 has a large diameter, the time is further extended until the rated discharge pressure is reached, the axial thrust balance device does not operate, and a large thrust load is applied to the ball bearing. Will be loaded.

[0008] When the pump is small and the pumping pipe has a small diameter, the filling time is short and the thrust equilibrium device operates at a relatively early time. In this case, the time required from the start of the pump to the time when the liquid fills the liquid pump pipe is further extended, and accordingly, the time when the thrust load is applied to the ball bearing is increased, and the bearing life is significantly shortened. Therefore, long-term stable operation of the pump could not be expected. Such a problem is described in Japanese Patent Application Laid-Open No. 7-102285. However, in the present invention, single row deep groove ball bearings are arranged in multiple rows, and the 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]

A single row deep groove type ball bearing arranged in a double row is fixed to a pump rotating shaft. In addition, the double row ball bearing is prevented from being displaced and a thrust load is uniformly applied. There were no fixtures. In the first place, ball bearings generally have a slight gap between the ball and the race (inner and outer races). For example, when the inner race race is fixed to the shaft, the outer race race moves in the axial and circumferential directions. There is backlash and deviation occurs. or,
If the ball is worn, the backlash will increase.

[0010] Deep groove ball bearings arranged in double rows are, for example, 2 ball bearings.
When arranged in rows, when the contact angle between the ball and the race of the deep groove ball bearing is equal in both the upper deep groove ball bearing and the lower deep groove ball bearing, the effect of uniform distribution of thrust load is exhibited.
When the rotating system including the double-row deep groove ball bearings operates in the axial direction due to the operation of the shaft thrust balance device or the behavior of the shaft, and the ball bearings are loose as described above, for example, when the inner ring side Even if the upper and lower deep groove type ball bearings are fixed to the shaft in parallel, the outer ring of the upper and lower deep groove type ball bearings cannot be separated from the ring spacer and there is nothing to fix the outer ring side in parallel. It is easy to cause backlash independently of each other. At that time, the outer ring and ring space of the upper and lower deep groove ball bearings
There is a gap between the gas and foreign matter in the liquefied gas
If a thrust load is applied in that state, the contact angle between the ball and the race may not be equal for both the upper deep groove ball bearing and the lower deep groove ball bearing. Damage occurs.

[0011] Further, although the wear of the ball and the race of the ball bearing is not extremely increased by the static pressure bearing and the shaft thrust parallel device, the wear is increased and the play of the outer race race is increased. In such a case, it is necessary to prevent the ring spacer from coming off the outer race race.

Further, when the outer races of the deep groove type ball bearings arranged in a double row are fixed to the bearing housing and the rotating shaft is movable in the axial direction, the wear of the ball bearings as described above is increased. If the backlash of the inner race becomes large, for example, at times, it is necessary to prevent the ring spacer from coming off the inner race.

In a conventional single-row deep-groove type ball bearing in a conventional submerged pump apparatus for a liquefied gas tank, the distribution of thrust load to upper and lower deep groove type ball bearings is ensured, and uniform distribution of thrust load is achieved. It is necessary to improve the reliability of the deep groove type ball bearings arranged in double rows.

An object of the present invention is to improve the function and reliability of a double-row deep-groove ball bearing and increase the life of the bearing under the circumstances 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.

[0015]

SUMMARY OF THE INVENTION The object of the present invention is to provide a submerged pump for a liquefied gas tank which is inserted into a pumping pipe suspended in a liquefied gas tank, sucks and discharges the liquefied gas from the liquefied gas tank. A drive unit for rotating and driving the pump shaft, an impeller provided at a position below the drive unit along the pump shaft to pressurize the liquefied gas sucked from the liquefied gas tank, and discharge the liquefied gas pressurized by the impeller. Discharge shaft, a plurality of bearings supporting the pump shaft, a balance disk attached to the pump shaft to balance the axial thrust, and a deep groove ball bearing arranged in a double row in a middle bearing provided near the balance disk. This is achieved by providing a retainer for fixing the outer ring or the inner ring of the deep groove type ball bearing arranged in a double row.

[0016]

FIG. 1 is a longitudinal sectional view of a vertical shaft submerged pump device for a liquefied gas tank. In the figure, those having the same reference numerals as those in FIG. 8 are the same as those in the prior art.

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

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

The pump 5 includes a rotary drive unit 5A provided at an upper position, an impeller unit 5B provided at a lower position, and a rotary shaft (shaft) 12. The rotation 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.
A motor is formed with the rotor unit 9 and the shaft 12 is rotated by rotating the rotor unit 9.

The impeller (impeller) section 5B includes 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, and the pressurized liquefied gas is sent to the discharge passage 5Q.

An upper bearing 16 is provided near a position where the shaft 12 is attached to the head cover 22 above the rotary drive portion 5A, and a lower bearing 1 is provided near the bottom portion 6 of the impeller portion 5B of the shaft 12.
4, and further, a middle bearing 15 is provided near a relay portion between the impeller portion 5 </ b> B and the rotation drive portion 5 </ b> A, and each supports the shaft 12. In addition, a hydrostatic bearing 19A is provided above the upper bearing 16.
Is provided. An axial thrust balance device 17 is provided around and below the middle bearing 15. The shaft thrust balance device 17 includes a cylindrical shaft sleeve 17A provided on the outer peripheral surface of the middle bearing 15,
It comprises a hydrostatic bearing 19B, a balance disk 17B and the like.
When the pump is started, the center bearing 15 supports the shaft 12. On the other hand, when the pump enters a normal operation state, the support by the center bearing 15 is released from the bearing housing 15A from the bearing housing 15A due to axial movement of the balance disk 17B. The thrust load acting on the middle bearing 15 is removed.

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

The double-row deep groove type ball bearing having the retainer attached to the middle bearing 15 is, for example, as shown in FIG. An important feature.

The static pressure bearings 19A and 19B are
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 deep groove type ball bearing having a plurality of arrangements of a submerged pump device for a liquefied gas tank according to the present invention.

The inside of the retainer 20 is machined with an appropriate fitting tolerance and coaxiality with the outer periphery of the outer race of the deep groove type ball bearing in a double row arrangement. The bearing housing 17A axial contact side is
Provide a seating surface that does not allow the rivets of the ball bearing to hit. A projection is provided on the upper part of the retainer 20 to prevent displacement in the axial direction, and when the ball bearing is inserted, it is inserted and fixed by the shrink fit principle.

FIG. 3 is a cross-sectional view of another embodiment of the deep groove type ball bearing having a plurality of arrangements of the immersion pump device for a liquefied gas tank according to the present invention.

The upper projection of the retainer 20 of the embodiment shown in FIG. 2 is eliminated, and the retainer is fixed to the retainer main body with a ring plate 21 and a bolt which is a screw fastening body. Fix the outer ring side of the deep groove ball bearing. It goes without saying that the axial height of the inner circumferential portion of the retainer main body is machined to an appropriate dimension required for fixing according to the height of the deep groove type ball bearings arranged in double rows.

According to the above-described embodiment, by installing the retainer on the outer ring side of the double-row deep groove ball bearing, the upper and lower two rows of deep groove ball bearing outer ring races are independently formed. And it is possible to maintain the parallelism so that the contact angle between the outer ring race and the ball of the deep groove type ball bearing upper and lower two rows becomes equal. As a result, the distribution of the thrust load is firmly distributed to the upper and lower deep groove ball bearings, and it can be ensured that the thrust load is evenly distributed. Also, in the unlikely event that wear of the ball or the like of the ball bearing increases the play, the ring spacer on the outer ring side is prevented from coming off due to unexpected behavior, and its function and reliability as a double-row deep groove ball bearing The performance can be improved.

In addition, a single row deep groove type ball bearing is arranged in a double row and is integrally fixed to the shaft 12 so that a gap is provided between the retainer 20 and the bearing housing 15d. Thrust balance equilibrium device 17
Needless to say, the axial movement is smoothly carried out, the thrust load is not applied to the ball bearing, and the radial load is operated with almost no load by the combination with the hydrostatic bearing. Can contribute.

FIG. 4 shows that the retainer for fixing the inner ring of the double-row deep groove type ball bearing of the liquefied gas tank submerged pump apparatus according to the present invention is provided in the circumferential direction of the double row deep-groove type ball bearing. It is fixed in a state that maintains appropriate fit and coaxiality.In the axial direction, the upper end has a seating surface on which the protrusion of the pump rotating shaft is mounted, and the lower end is a deep groove ball bearing arranged in multiple rows. The protrusions are inserted and fixed to form an integrated structure, which improves the workability of assembly.

Referring to FIG. 5, the retainer for fixing the inner ring of the deep groove ball bearings arranged in a double row is fixed in the circumferential direction of the deep groove ball bearings arranged in a double row while maintaining an appropriate fit and coaxiality. In the axial direction, the upper end has a seating surface on which the projection 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. By fixing a ring-shaped plate with a screw fastener to the extent that suppresses the inner ring of the bearing, the inner ring of the deep groove type ball bearing arranged in multiple rows is fixed and a split type structure, so that cold fitting work is unnecessary. Yes, only machining is required.

[0033]

According to the vertical shaft type submerged pump device for a liquefied gas tank, the thrust load to be applied at the time of starting the pump is arranged in double rows of deep groove type ball bearings, thereby ensuring uniform load distribution.
The function and reliability of the double-row deep groove ball bearing are improved, and the long life of the bearing enables long-term stable operation of the pump.

[Brief description of the drawings]

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

FIG. 2 is a sectional view of an embodiment of the double grooved deep groove ball bearing of the present invention.

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

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

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

FIG. 6 is a schematic sectional view of a conventional immersion pump equipment for a liquefied gas tank.

FIG. 7 is a system head curve immediately after activation of a submerged pump for a liquefied gas tank.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Liquefied gas tank, 2 ... Liquid pipe, 3 ... Suction valve, 4 ... Hanging wire, 5 ... Submersible 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 deep groove ball bearing, 15c: Ring spacer,
15f: ball, 15g: cage, 16: upper bearing, 17
... Axial thrust balance device, 18 ... Casing, 19A, 1
9B: hydrostatic bearing, 20: retainer, 21: ring-shaped plate, F: load, θ: contact angle

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-1-301990 (JP, A) JP-A-7-317695 (JP, A) JP-A-7-119680 (JP, A) 41694 (JP, U) Shokai Sho 59-62299 (JP, U) JP-B 61-5558 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) F04D 7/02 F04D 13 / 08

Claims (5)

(57) [Claims] 1. A liquefied gas tank submerged pump device which is inserted into a liquid pumping pipe suspended in a liquefied gas tank, sucks and discharges liquefied gas from the liquefied gas tank, and drives a pump shaft and a rotary drive of the pump shaft. Part, provided at a position below the drive unit along the pump shaft, and an impeller that pressurizes the liquefied gas sucked from the liquefied gas tank, a discharge hole that discharges the liquefied gas pressurized by the impeller, and a pump shaft. It is composed of a plurality of bearings to be supported, a balance disk attached to the pump shaft to balance the axial thrust, and a deep groove ball bearing arranged in a double row in a middle bearing provided near the balance disk and arranged in a double row. A vertical shaft submerged pump device for a liquefied gas tank, comprising a retainer for fixing an outer ring or an inner ring of a deep groove ball bearing. 2. A vertical shaft type submerged pump device for a liquefied gas tank according to claim 1, wherein the retainer for fixing the outer ring of the double-row deep groove ball bearing is arranged in the circumferential direction of the double-row deep groove ball bearing. In the axial direction, the lower end has a seating surface on which the outer ring of the ball bearing can be placed, and the upper end has a double-row deep groove ball bearing. A vertical shaft submerged pump device for a liquefied gas tank, wherein the vertical shaft type submerged pump device has an integral structure in which a projection portion is inserted and fitted and fixed. 3. A vertical shaft submerged pump device for a liquefied gas tank according to claim 1, wherein the retainer for fixing the outer ring of the double-row deep groove ball bearing is arranged in the circumferential direction of the double-row deep groove ball bearing. In the axial direction, the lower end has a seating surface on which the outer ring of the ball bearing can be placed, and the upper end has a double-row deep groove ball bearing A split-type structure that has a precision machined surface that matches the height, and fixes the outer ring of a deep groove type ball bearing arranged in multiple rows by fixing a ring-shaped plate that suppresses the outer ring of the ball bearing with a screw fastener. A vertical shaft submersible pump device for a liquefied gas tank. 4. A vertical shaft submerged pump device for a liquefied gas tank according to claim 1, wherein the retainer for fixing the inner ring of the double-row deep groove ball bearing is arranged in the circumferential direction of the double-row deep groove ball bearing. In the axial direction, the upper end has a seat surface on which the protrusion of the pump rotating shaft is mounted, and the lower end has a deep groove type ball arranged in multiple rows. A vertical shaft submerged pump device for a liquefied gas tank, wherein the vertical shaft submerged pump device has an integral structure which is fixed by providing a protruding portion that is inserted into the bearing after being cooled. 5. The vertical shaft type submerged 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 a double row is arranged in the circumferential direction of the deep groove type ball bearings arranged in a double row. In the axial direction, the upper end has a seat surface on which the projection of the pump rotating shaft is mounted, and the lower end has a double-row deep-groove ball bearing in the axial direction. The split-type structure has a precision machined surface that matches the height of the ball bearing, and fixes the inner ring of a deep groove type ball bearing that is arranged in multiple rows by fixing a ring-shaped plate that suppresses the inner ring of the ball bearing with a screw fastener A vertical shaft submerged pump device for a liquefied gas tank.