JP3483907B2 - Submersible pump with reverse rotation prevention mechanism - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a submerged pump for a liquefied gas tank, and more particularly, it is suitable for preventing reverse rotation of a pump rotating shaft due to reverse flow of liquefied gas remaining in a pumping pipe when the pump is stopped. The present invention relates to a submersible pump for a liquefied gas tank.

[0002]

2. Description of the Related Art A conventional submersible pump for liquefied gas is disclosed in
As in Japanese Patent Laid-Open No. 1-301990, no reverse rotation preventing mechanism is provided, and the rotating shaft is supported only by the bearings above and below the drive unit, so that the structure can rotate in both forward and reverse directions.

[0003]

As described above,
In the above conventional technique, during pump operation, liquefied gas is sucked up by the impeller from the suction port provided at the lower part of the pump, passes through the impeller and the stage, and is discharged from the pump body discharge hole. The liquefied gas discharged from the pump body passes through the pumping pipe and is discharged from the discharge pipe.

When the pump is stopped, a differential pressure is generated due to the difference in the liquid level between the liquefied gas remaining in the pump and the liquefied gas in the tank, and the liquefied gas in the pump flows back into the tank through the pump. . When the liquefied gas flows backward in the pump, the pump rotating body rotates in the reverse direction. If the motor is restarted while it is rotating in the reverse direction, excessive force may be applied to the rotating shaft and damage it.Also, if the motor cannot continue rotating, excessive current will flow for a long time and the motor will burn out. there is a possibility.
Due to the above problems, it is necessary to wait for tens of minutes before the reverse rotation is stopped before restarting the pump.

Generally, a liquefied gas plant has a commercial power source and an emergency power source during a power failure. If the commercial power supply stops, it will switch to the emergency power supply within a few minutes. When the pump stops due to a power failure, gas cannot be produced while the pump is stopped, and if this state continues for several tens of minutes until the pump can be restarted, the social impact will increase. Need to reboot.

An object of the present invention is to obtain a submerged pump for a liquefied gas tank , which can restart the pump at the same time as switching the emergency power source even in the case of a power failure , thereby enabling stable gas production.

[0007]

In order to achieve the above object, the present invention provides an impeller, a rotating shaft for rotating the impeller, a pump portion including a casing for housing these, and an upper portion of the pump portion. Directly connected to the rotary shaft, including a drive unit for rotating the impeller, liquefied gas is sucked up by the impeller from the suction port provided in the lower portion of the pump, and discharged from the discharge port of the pump body,
The discharged liquefied gas is a submerged pump for a liquefied gas tank configured to be discharged from a discharge pipe through a pumping pipe, and a rotating disc provided on a rotary shaft between the impeller and the discharge port. A pressure receiving plate provided at the discharge port so as to be lifted upward by the pressure of the pump discharge liquid when the pump is operating, and pressed against the rotating disk below by the liquefied gas that flows backward when the pump is stopped, A reverse rotation preventing mechanism configured to prevent reverse rotation of the pump by utilizing a frictional force when the pressure receiving plate is pressed against the rotating disk is provided.

Another feature of the present invention is that an impeller, a rotary shaft for rotating the impeller, a pump portion including a casing for housing the impeller, and a pump portion directly connected to the rotary shaft at an upper portion of the pump portion. A drive unit for rotating the pump, and liquefied gas is sucked up by the impeller from the suction port provided at the lower part of the pump and discharged from the discharge port of the pump body.The discharged liquefied gas passes through the pumping pipe. In a submerged pump for a liquefied gas tank configured to discharge from a discharge pipe, a rotary plate fixed to the rotary shaft and having a friction surface on a lower surface, and the pump so as to face the lower surface of the rotary plate. A fixed plate which is fixedly provided on the main body and has a friction surface on its upper surface, the rotary plate moves upward while the rotary shaft floats during pump operation, and when the pump is stopped, A reverse rotation preventing mechanism is provided which is configured to prevent the reverse rotation of the pump by utilizing the frictional force at that time when the rotary plate moves downward and is pressed against the fixed plate as it descends. .

[0009]

Since the present invention has the reverse rotation preventing mechanism,
Unnecessary force does not act on the rotating body of the pump such as the rotating shaft, impeller and motor, and the life of the rotating body of the pump can be secured.

[0010]

DETAILED DESCRIPTION FIG. 1 is a longitudinal sectional view showing a reference technique of the inverse liquefied gas tank rotation prevention mechanism with submersible pump is, FIGS. 2 and
Figure 3 is Ru enlarged cross-sectional view der of the main part of FIG. In the figure,
The outer race 4 and the cam 5 are rotated by the motors 7a and 7b, similarly to the impeller 1, the rotating shaft 2 and the balance disc 3. The inner race 6 is fixed to the head cover 8 by bolts (not shown).

[0011] cam 5, the impeller 1, the rotary shaft 2, balancing disc 3, when the outer race 4 is not rotated, the moment acting about the point of contact with the A Utaresu 4 and the cam 5 is increased, FIG. 3 As shown in, the inner race 4 is in contact. When the impeller 1, the rotating shaft 2, the balance disc 3, the outer race 4 and the cam 5 are rotated forward and reach a certain number of revolutions or more, the cam 5 has no contact with the inner race 6 as shown in FIG.
Cam 5 does not wear.

When the impeller 1, the rotating shaft 2, the balance disc 3, and the outer race 4 rotate in the opposite directions, the moment acting on the cam 5 around the contact point between the outer race 4 and the cam 5 becomes small, and the cam 5 contacts the inner race 6. Have a
The cam 5 engages with the outer race 4 and the inner race 6 to prevent reverse rotation.

According to the reference technique, in <br/> state of the rotating body is reverse rotation, since there is no Rukoto restart the pump, the rotating shaft is damaged, in a state in which the motor can not rotate < The possibility of burning the motor can be reduced .

Next, a first embodiment of the present invention will be described with reference to FIGS.
Will be described. 4 and 5 are the latent images shown in FIG. 1, respectively.
Main part corresponding to the structure near the balance disk of the submersible pump
FIG.

On the rotary shaft 2 between the impeller 1 and the discharge port 12,
Is provided with a rotating disk 11, and the discharge port 12 has a liquefied gas.
A pressure receiving plate 10 that moves up and down by the pressure of the
It When the pump is operating, the flow of the pump discharge liquid is indicated by the arrow in FIG.
As shown in, the fluid whose pressure is increased by the impeller 1
Through the 2 Ru it is discharged into the liquid being pumped tube. At this time, the pressure receiving plate 10 is lifted above the pump by the dynamic pressure of the pump discharge liquid, and as shown in FIG. 4, the pressure receiving plate 10 does not contact the rotating disc 11 provided on the rotating shaft 2. That is, when the pump is operated in the forward rotation, the pressure receiving plate 10 and the rotary disk 11
Does not touch and does not wear.

The pump is stopped and the liquefied gas is shown in FIG.
As such, when the backflow of the discharge port 12, the pressure receiving plate 10 is eclipsed with pushing to the rotatable disk 11 by the dynamic pressure of the liquefied gas, the pressure receiving plate 1
The reverse rotation of the pump can be prevented by the frictional force caused by the contact between 0 and the rotating disk 11.

According to this embodiment, the rotating body is in the reverse rotation state.
Will not restart the pump,
Loss and motor burnout can be prevented.

Next, a second embodiment of the present invention will be described with reference to FIGS.
Will be described . 6 and 7 are the latent images shown in FIG. 1, respectively.
Expansion of the main parts corresponding to the structure near the upper end of the rotary shaft 2 of the submersible pump
FIG.

In FIG. 6 and FIG. 7 , 16 is on the rotary shaft 2.
Rotating plate fixed on the end side and having a friction surface on the lower surface,
15 is a pump book so that it faces the lower surface of the rotary plate 16.
With a fixed plate that is fixed to the body and has a friction surface on its upper surface
is there. During pump stop, as shown in FIG. 7, the rotation shaft 2
Is hanging below the pump. During pump operation , the rotary shaft 2 is in a floating state as shown in FIG. As a result, the rotary plate 16 attached to the rotary shaft 2
6 is not in contact with the fixed plate 15 during pump operation as shown in FIG. When the pump is lowered into the pump downwards from a state where the rotary shaft 2 floats stopped, as shown in FIG. 7, the rotary plate 1
6 and the fixing plate 15 is come in contact. This rotating plate 16 and the fixing plate 1
The reverse rotation of the pump can be prevented by the frictional force caused by the contact with 5.
Come, the same effects as in Example 1 Ru obtained.

[0020]

According to the present invention, as described above, the rotating member (rotating disc or rotating plate) fixed to the rotating shaft and the fixing member (pressure receiving plate or fixing plate) provided on the pump body side are provided. Has a reverse rotation prevention mechanism that makes contact when the pump is stopped and uses the frictional force at that time to prevent reverse rotation of the pump. Reverse rotation of the shaft can be prevented by a simple structure provided in the pump. As a result, even if the commercial power supply stops and the pump stops due to a power outage, etc., the reverse rotation of the pump can be prevented, so that the pump can be restarted immediately after switching to the emergency power supply, and stable gas production can be achieved. There is an effect that a submersible pump for a liquefied gas tank that can be obtained can be obtained.

[Brief description of drawings]

[Figure 1] Submersible pump with reverse rotation prevention mechanism for liquefied gas tank
Sectional drawing which shows the reference technique of .

Figure 2 is an enlarged cross-sectional view of a main part of FIG.

Figure 3 is an enlarged cross-sectional view of a main part of FIG.

FIG. 4 is an enlarged vertical sectional view of an essential part showing the first embodiment of the present invention.
The structure near the balance disk of the submersible pump shown in Fig. 1
The figure corresponding to the structure.

FIG. 5 is an enlarged vertical sectional view of an essential part showing the first embodiment of the present invention.
The structure near the balance disk of the submersible pump shown in Fig. 1
The figure corresponding to the structure.

[6] main portion expand large longitudinal sectional view showing a second embodiment of the present invention
The structure near the upper end of the rotary shaft 2 of the submersible pump shown in FIG.
Figure corresponding to.

[7] main portion expand large longitudinal sectional view showing a second embodiment of the present invention
The structure near the upper end of the rotary shaft 2 of the submersible pump shown in FIG.
Figure corresponding to.

[Explanation of symbols]

1 ... Impeller, 2 ... Rotation axis, 3 ... Balance disc, 4
… Outer race, 5… Cam, 6… Inner race, 7
a, 7b ... Motor, 8 ... Head cover, 10 ... Pressure receiving plate,
11 ... Rotating disk, 12 ... Discharge port, 15 ... Fixed plate, 16 ...
Rotating plate.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References Japanese Patent Laid-Open No. 2-11890 (JP, A) Japanese Patent Laid-Open No. 61-19996 (JP, A) Actual Public Japanese Patent No. 41-13185 (JP, Y1) (58) Field (Int.Cl. ⁷ , DB name) F04D ⁷ /00-13 / 06,29 / 04

Claims (2)

(57) [Claims] 1. A pump unit including an impeller, a rotary shaft for rotating the impeller, a casing accommodating the impeller, and a drive unit for directly rotating the impeller on the upper portion of the pump unit, the rotary unit being directly connected to the rotary shaft. Liquefied gas is sucked up by the impeller from the suction port provided at the lower part of the pump and discharged from the discharge port of the pump main body,
The discharged liquefied gas is a submerged pump for a liquefied gas tank configured to be discharged from a discharge pipe through a pumping pipe, wherein a rotary disc provided on a rotary shaft between the impeller and the discharge port. A pressure receiving plate provided at the discharge port so as to be lifted upward by the pressure of the pump discharge liquid when the pump is operating, and pressed against the rotating disk below by the liquefied gas that flows backward when the pump is stopped, Submersion with a reverse rotation prevention mechanism, characterized in that a reverse rotation prevention mechanism is provided to prevent reverse rotation of the pump by utilizing the frictional force when the pressure receiving plate is pressed against the rotating disk. pump. 2. An impeller, a rotary shaft for rotating the impeller, a pump portion including a casing for housing the impeller, and a driving portion for rotating the impeller, which is directly connected to the rotary shaft at an upper portion of the pump portion. Liquefied gas is sucked up by the impeller from the suction port provided at the lower part of the pump and discharged from the discharge port of the pump main body,
In the submerged pump for a liquefied gas tank configured so that the discharged liquefied gas passes through the pumping pipe and is discharged from the discharge pipe, a rotary plate fixed to the rotary shaft and having a friction surface on the lower surface is provided. A fixed plate that is fixed to the pump main body so as to face the lower surface of the rotary plate and has a friction surface on the upper surface thereof, and the rotary plate moves upward with the floating of the rotating shaft during pump operation. When the pump is stopped, the rotary plate is lowered and pressed against the fixed plate as the rotary shaft is lowered,
A submersible pump with a reverse rotation preventing mechanism, comprising a reverse rotation preventing mechanism configured to prevent reverse rotation of the pump by utilizing frictional force at that time.