JPH03282296A - Apparatus for preventing reversal of internal pump - Google Patents

Abstract

PURPOSE:To transmit large torque by respectively connecting an auxiliary impeller, the rotary ring and stationary ring of a reversal preventing apparatus and a lower cover by a ring gear-shaped engaging part. CONSTITUTION:A reversal preventing apparatus 32 is constituted of the rotary ring 22 mounted on the lower part of an auxiliary impeller 17 so as to be integrally rotated along with the impeller 17, the stationary ring 24 concentric to the rotary ring 22 and fixed to a lower cover 23 and a plurality of the cams 26 mounted on the inside of the rotary ring 22 in a freely revolvable manner using retainer rings 25a, 25b and ring gear-shaped engaging parts 33, 34 are respectively provided to the connection pat of the rotary ring 22 and the auxiliary impeller and the connection part of the stationary ring 24 and the lower cover 23 and clamped by bolts 35, 36 to be integrated. By employing these ring gear-shaped engaging parts, a part transmitting large torque can be easily disassembled and assembled only by bolts.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention relates to an internal pump that is attached to a nuclear reactor pressure vessel and forcibly circulates reactor water. This invention relates to improvement of a reverse rotation prevention device.

(Prior Art) FIG. 4 shows a state in which an internal pump 2 is attached to a reactor pressure vessel 1. As shown in the same figure, a plurality of internal pumps 2 are installed in a circumferential manner at the bottom of the reactor pressure vessel 1, and as shown in FIG. Water is discharged from below (arrow 4), and the discharged reactor water is forced to circulate through the reactor core 5.

As shown in FIG. 6, the internal pump 2 is composed of a main impeller section 6, a submersible motor section 7 that drives the main impeller section 6, and a reverse rotation prevention device 8 provided at the bottom of the submersible motor section 7. has been done.

Here, the main impeller section 6 is composed of a main impeller 10 attached to a pump shaft 9 and a guide vane 11 attached to the inside of the reactor pressure vessel 1. In addition, the underwater motor section 7
The motor shaft 13 is completely separated from the reactor water in the reactor pressure vessel 1 by the purge water 12, and is fitted into the lower part of the pump shaft 9 and connected to the pump shaft 9, and the rotor 14 attached to the motor shaft 13. , the stator 16 installed inside the motor casing 15, and the motor shaft 13 are connected to the upper radial bearing 18.
The auxiliary impeller 17 is supported by an upper thrust bearing 20 and a lower thrust bearing 21 by a lower radial bearing 19 and a lower radial bearing 19 .

Furthermore, as shown in FIG. 7, the reverse rotation prevention device 8 includes a rotating ring 22 fixed to the lower part of the auxiliary impeller 17 so as to rotate together with the rotating ring 22, and a stationary ring 22 fixed to the lower cover 23 concentrically with the rotating ring 22. It is rotatably attached to the inside of the ring 24 and the one-rotation ring 22 via retainer rings 25a and 25b, and is composed of a plurality of cams 26 each having an approximately diamond-shaped cross section with two opposing faces being circular arcs. When the rotating ring 22 rotates in one direction, the cam 26 rotates due to the action of centrifugal force and does not come into contact with the stationary ring 24, and when the rotating ring 22 rotates in the opposite direction, the cam 26 returns to its original position under the action of a spring (not shown). It has a function of stopping the rotation of the rotating ring 22 by imitation by contacting the stationary ring 24, and has a structure similar to that used in practical use as a one-way cam clutch.

The reverse rotation prevention device 8 configured as described above acts on the internal pump 2 as follows.

That is, in order to improve the safety of the reactor, a plurality of internal pumps 2 are installed at the bottom of the reactor pressure vessel 1, and even if one or two pumps are stopped, the remaining internal pumps Pump 2 is designed to operate the reactor safely. However, if one or two internal pumps 2 stop operating like this, reactor water flows back into the main impeller 10, so the internal pumps 2
is reversed, causing vibration. Therefore, a reversal prevention device 8 is provided to prevent the internal pump 2 from reversing and to prevent vibrations from occurring.

In FIG. 6, 27 is a motor upper chamber, 28 is a pipe, 29 is a heat exchanger, 30 is a rear pipe, and 31 is an impeller suction port.

(Problems to be Solved by the Invention) The above-mentioned internal pump reverse rotation prevention device is required to have the following functions.

■ It must be firmly fixed because it must withstand the large reversing torque that occurs when reactor water flows backwards.

■ During periodic inspections, the reverse rotation prevention device is disassembled and inspected, so it is necessary to have a structure that is easy to disassemble. Also,
It must be possible to securely and easily fix it when reassembling it. Furthermore, in order to maintain the balance of the rotating body, it is necessary to perform centering with high accuracy and to create a structure that does not require balance adjustment after assembly.

(3) Since the rotation speed is adjusted using an inverter power supply, minute torque fluctuations occur in the rotor. Therefore, parts fixed to the rotor should be assembled with as little play as possible to avoid relative movement and wear.
It is necessary to have a structure that allows centering.

By the way, the reversal prevention device is usually fixed using the rotating ring 22.
This is done by inserting the key 22a between the auxiliary impeller 17 and the auxiliary impeller 17 and tightening both with bolts (not shown), and inserting the key 24a between the stationary ring 24 and the lower cover 23 and tightening both with bolts (not shown). ing. However, large keys cannot be used due to size limitations. Therefore, a double key is used to prevent the key stress from becoming excessive when a large reverse torque is applied, but disassembling and assembling is difficult, resulting in large play during assembly.

As a result, the installation may result in relative movement and wear of the parts.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a reverse rotation prevention device for an internal pump that solves such problems.

[Structure of the invention]

(Means for Solving the Problems) The present invention provides a motor shaft that constitutes a submersible motor integrally at the lower part of a pump shaft, a rotor integrally provided to this motor shaft, and an auxiliary device for circulating cooling water in the lower part. An impeller is provided, a cylindrical rotating body is integrally provided on the lower surface of this auxiliary impeller, a cam is rotatably provided inside this cylindrical rotating body, and this cam rotates and contacts when the pump shaft rotates in reverse. In a reverse rotation prevention device for an internal pump equipped with a cylindrical stationary body that stops reverse rotation, a ring gear-like lock is provided between the auxiliary impeller and the cylindrical rotating body, and between the cylindrical stationary body and the lower cover. This is a combination of two parts.

(Function) Since the auxiliary impeller and the cylindrical rotating body of the reverse rotation prevention device and the cylindrical stationary body of the reverse rotation prevention device are connected via ring gear-shaped locking parts, the ring gear-shaped locking The self-aligning properties of the parts, no backlash, high reproducibility of assembly, ability to transmit large torque, and the effect of facilitating assembly work can also be obtained.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view showing one embodiment of the present invention.

As shown in the figure, the reverse rotation prevention device 32 is connected to the auxiliary impeller 1.
7, a stationary ring 24 fixed to the lower cover 23 concentrically with the rotating ring 22, and a retainer ring 25a, 25b inside the rotating ring 22. It is composed of a plurality of rotatably mounted cams 26, and a ring gear-shaped locking part 33 is provided at the joint between the rotating ring 22 and the auxiliary impeller, and at the joint between the stationary ring 24 and the lower cover 23.
．． 34 are provided and are tightened and integrated with bolts 35 and 36.

The ring gear-shaped locking portion 33 has an outer diameter and an inner diameter corresponding to the rotating ring 22, and has a locking portion 33a provided with teeth on the lower surface of the auxiliary impeller 17 as shown in FIG. A locking portion 33 provided on the upper surface of the rotating ring 22 with teeth that mesh with the
It is composed of b. Further, the ring gear-like locking portion 34 is
The outer diameter and inner diameter correspond to the lower part of the stationary ring 24,
As shown in the figure, the stationary ring 24 consists of a locking part 34a provided with teeth as shown in the figure, and a locking part 34b provided on the top surface of the lower cover 23 with teeth that mesh with the teeth. However, for convenience of explanation, FIGS. 2 and 3 show the ring gear-like locking parts 33 and 34 as independent shapes, and FIG. 2 shows them in an unengaged state, and FIG. It shows the condition.

Next, the operation of the embodiment configured as above will be explained. As shown in FIG. 2, the ring gear-shaped locking portion is a cylinder with teeth radially machined on the end surface, and has the following characteristics.

ω Since it has self-aligning properties, it can be centered accurately,
No need for balance work after assembly.

■ Can be joined without any play.

■ Relative movement while driving can be prevented.

(b) Easy to assemble.

■ Can transmit large torque.

By employing a ring gear in this manner, parts that transmit large torque can be easily disassembled and assembled by simply tightening bolts.

〔Effect of the invention〕

As explained above, according to the present invention, the auxiliary impeller and the rotating ring of the anti-reverse device, and the stationary ring of the anti-reverse device and the lower cover are each connected by a ring gear-like locking portion, so that the conventional key connection is not possible. Compared to (1), the capacity of the reverse rotation prevention device is not limited by the key stress generated by reverse rotation torque, and a large torque can be transmitted.

■ Easy to disassemble and assemble.

■ Centering work is not required.

(b) Relative movement during driving can be prevented.

It is possible to provide a reverse rotation prevention device for an internal pump that has the following effects.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing the main part of an embodiment of the present invention, Fig. 2 is a perspective view of a ring gear-shaped locking part used in an embodiment of the invention, and Fig. 3 is shown in Fig. 2. FIG. 4 is an explanatory diagram showing a state in which the ring gear-shaped locking portions are engaged; FIG. Fig. 5 is an explanatory diagram showing the operation of the internal pump related to the present invention, Fig. 6 is a sectional view of an internal pump equipped with a conventional anti-reverse device, and Fig. 7 shows the main parts of the conventional anti-reverse device. FIG. 1... Reactor pressure vessel 9... Pump shaft 13... Motor shaft 22... Rotating ring 24... Stationary ring 32... Reversal prevention device 2... Internal pump 10... Main Impeller 17...Auxiliary impeller 23...Lower cover 26...Cam 33.34...Ring gear-shaped locking part (8733)
Agent: Patent Attorney Yoshiaki Inomata (and 1 other person)

Claims (1)

[Claims] A motor shaft that constitutes a submersible motor is provided integrally at the bottom of the pump shaft, a rotor is provided integrally with this motor shaft, and an auxiliary impeller for circulating cooling water is provided at the bottom of the motor shaft. A cylindrical rotating body, a cam rotatably provided inside the cylindrical rotating body, and a cylindrical stationary body that rotates and comes into contact with the pump shaft when the pump shaft is reversed, thereby stopping the reverse rotation. In the internal pump reverse rotation prevention device, a ring gear-like locking portion is provided between the auxiliary impeller and the cylindrical rotating body, and between the cylindrical stationary body and the lower cover, respectively. Features a reverse rotation prevention device for internal pumps.