KR102609343B1 - Vertical pump test device for reducing high vibration and resonance - Google Patents

Abstract

A vertical pump test device according to the present invention includes a support frame that supports a load and forms a receiving space therein, and an upper frame installed on the support frame; A water tank installed in the receiving space, containing fluid at a set water level therein, and having a fluid disturbance device installed on the lower surface to generate fluid vibration; A motor installed on top of the upper frame and a motor stand supporting the motor; A pipe connecting the inside of the water tank and the motor stand and through which fluid moves along the inside; A pumping pipe installed at the lower part of the motor stand, containing fluid at a set water level therein, and having one end in communication with the inside of the water tank; and a vibration detection sensor installed on one side of the pumping pipe to measure vibration generated by driving the motor.

Description

Test device for reducing high vibration and resonance of vertical pumps {VERTICAL PUMP TEST DEVICE FOR REDUCING HIGH VIBRATION AND RESONANCE}

The present invention relates to a test device for reducing high vibration and resonance of a vertical pump.

Nuclear power plants use nuclear fuel inside a nuclear reactor to heat the primary coolant with the energy generated during nuclear fission. The heat energy is transferred from the steam generator to the secondary coolant, and the generated steam is converted into rotational energy in the steam turbine and used as a generator. It is a system that produces electricity using

A nuclear power plant includes a nuclear reactor, a generator, a turbine, and piping. Among these, the turbine, the core equipment of the power plant, is a mechanical device that uses the flow of compressive fluid such as steam or gas to obtain rotational power through reaction force. means.

In general, a pump refers to a device that transports fluid through a pipe by the action of pressure, or pumps fluid in a low-pressure container into a high-pressure container through a pipe.

Types of pumps include reciprocating pumps, centrifugal pumps, axial flow pumps, friction pumps, etc. Centrifugal pumps transport or pump fluid using centrifugal force generated by rotating one or more impellers in a closed casing. In particular, a vertical pump is called a vertical pump that pressurizes and supplies the liquid below by having an intake inlet located at the bottom and an electric device located at the top. In power plants and industrial plants, a shaft is used for cooling water circulation. A large, long vertical shaft pump is used.

Due to its structure and installation location, it is difficult to perform performance tests on vertical long axis pumps by installing a flow or pressure control valve at the front of the pump or installing a vacuum pump to control pressure, so it is difficult to test various conditions within the tank where the vertical long axis pump is installed. It is necessary to perform performance tests while making changes.

In particular, vertical pumps are widely used in power plants due to efficient space utilization and economic efficiency. However, due to the structural characteristics of the vertical pump, there is a high risk of vibration and resonance occurring, and this is related to the dynamic characteristics of the fixed and rotating parts. In the past, vibration and resonance of the vertical pump were avoided by changing the dynamic characteristics (stiffness, mass, etc.) of the fixture. However, even in the case of the rotating part, there is a risk that various types of vibration or resonance may occur in the vertical pump due to mass imbalance, axial misalignment, fluid vibration, and separation between components.

Accordingly, by changing the test conditions in various ways using a vertical pump test device, it is possible to study whether vibration and resonance occur in the vertical pump due to the rotating part and how to deal with them.

KR Registered Patent No. 10-1453540 (registered on October 15, 2014)

One purpose of the present invention is to examine the vibration and resonance characteristics that occur in a vertical pump according to the driving of the rotating body and to obtain a method to avoid them.

Another purpose of the present invention is to propose a structure of a device that can analyze vibration and resonance characteristics occurring in a vertical pump test device while changing the dynamic characteristics of the rotating body.

In order to achieve an object of the present invention, a vertical pump test device according to an example of the present invention includes a support frame that supports a load and forms a receiving space therein, and an upper frame installed on the support frame; A water tank installed in the receiving space, containing fluid at a set water level therein, and having a fluid disturbance device installed on the lower surface to generate fluid vibration; A motor installed on top of the upper frame and a motor stand supporting the motor; A pipe connecting the inside of the water tank and the motor stand and through which fluid moves along the inside; A pumping pipe installed at the lower part of the motor stand, containing fluid at a set water level therein, and having one end in communication with the inside of the water tank; and a vibration detection sensor installed on one side of the pumping pipe to measure vibration generated by driving the motor.

According to an example of the present invention, it may further include an imbalance generator installed on an upper portion of the motor and an imbalance plate coupled to the imbalance generator.

According to an example of the present invention, the connection between the motor and the amniotic fluid pipe may further include a fitting member inserted into the connection to cause misalignment of the rim portion of the connection.

According to one example of the present invention, a pipe connection portion is formed to protrude on one side of the motor stand to support the pipe insertion, and the pipe connection portion may extend in one direction and then branch in both directions.

According to an example of the present invention, the pipe includes: a first pipe extending from the pipe connection portion and bent with a constant curvature; And it may include a second pipe that is separated from the first pipe and extends.

According to one example of the present invention, different motors and motor stands are installed side by side on the upper part of the upper frame, and a rigid additional device for hydraulic pressure adjustment may be installed between the motor stands.

According to one example of the present invention, vibration analysis equipment may be included for precise detection of vibration occurring as the motor is driven.

The vertical pump test and inspection device having the above structure can measure and analyze the vibration detected by the vibration sensor as the motor drives, analyze the cause of vibration and resonance, and find ways to avoid it. there is.

In addition, by measuring vibration while changing the dynamic characteristics of the rotating body, such as mass imbalance of the rotating body, misalignment of the rim of the pumping pipe connection, and fluid flow, the causes of vibration and resonance that can occur in the vertical pump are analyzed. And you can find a way to avoid this.

Figure 1 is a perspective view showing the overall structure of a vertical pump test device.
Figure 2 is an enlarged view of the upper part of the vertical pump test device.
Figure 3 is a top view of the vertical pump test device.
Figure 4 is a partial enlarged view of the lower part of the vertical pump test device.

Hereinafter, the vertical pump test device related to the present invention will be described in more detail with reference to the drawings.

In this specification, identical and similar reference numbers are assigned to identical and similar components even in different embodiments, and overlapping descriptions thereof are omitted.

In addition, even if the embodiments are different from each other, the structure applied to one embodiment may be equally applied to another embodiment as long as there is no structural or functional contradiction.

Singular expressions include plural expressions unless the context clearly dictates otherwise.

In describing the embodiments disclosed in this specification, if it is determined that detailed descriptions of related known technologies may obscure the gist of the embodiments disclosed in this specification, the detailed descriptions will be omitted.

The attached drawings are only for easy understanding of the embodiments disclosed in this specification, and the technical idea disclosed in this specification is not limited by the attached drawings, and all changes, equivalents, and changes included in the spirit and technical scope of the present invention are not limited. It should be understood to include water or substitutes.

Hereinafter, in the detailed description of the invention, the front or front part may be understood as meaning the right side of the drawing, and the back or rear part may be understood as meaning the left side of the drawing. In addition, the top or upper side can be understood as meaning upward in the vertical direction of the drawing, and the lower or lower side can be understood as meaning downward in the vertical direction.

Figure 1 is a perspective view showing the overall structure of the vertical pump test device 100.

The vertical pump test device 100 implements the vibration form of the rotating body that can occur in the vertical pump and changes the dynamic characteristics (stiffness, damping, etc.) to check whether high vibration and resonance that can occur in the vertical pump occur. do.

The vertical pump test device 100 includes a support frame 110, an upper frame 111, a water tank 120, a motor 130 and a motor stand 131, a pipe 140 and a pumping pipe 123, and a vibration It may include a detection sensor 125.

The support frame 110 forms the exterior of the vertical pump test device 100, serves to support the overall load, and has a receiving space therein. The support frame 110 is made up of four bars and bars connecting them and can be formed to have sufficient strength.

The upper frame 111 is installed on the upper part of the support frame 110 and has a flat upper surface so that the motor 130 and the motor stand 131 can be installed.

The water tank 120 may have a cylindrical shape with an open upper surface, and may contain fluid therein. Here, the fluid may mean water. The water tank 120 may be installed in the receiving space formed by the support frame 110.

Fluid may be accommodated inside the water tank 120 to have a constant water level.

The motor 130 is installed on the top of the upper frame 111 and consists of a rotor and a stator to generate driving force and serves to provide power to supply water toward the water tank 120. The rotation speed of the motor 130 may be set arbitrarily, for example, between 0 and 7200 rpm.

The motor stand 131 is installed on the upper frame 111, is located between the motors 130, and serves to support the motor 130. At the bottom of the motor stand 131, a positive water pipe 123 may be installed in communication.

A piping connection part 161 is installed on one side of the motor stand 131 so that the piping 140 can be connected to it.

The pipe 140 serves to connect the inside of the water tank 120 and the motor stand 131, and allows water to move between the water tank 120 and the pumping pipe 123 through the pipe 140. .

The pumping pipe 123 is installed at the lower part of the motor stand 131, extends a certain length, and one end communicates with the inside of the water tank 120. The motor stand 131 and the pumping pipe 123 may be formed as a pair to correspond to the motor 130.

The pumping pipe 123 can accommodate fluid at a constant water level, and the motor 130 is driven while the fluid at a constant water level is accommodated inside the water tank 120, and the pumping pipe ( By measuring the vibration occurring in 123), the natural frequency of the vertical pump can be calculated.

The vibration detection sensor 125 may be installed on one side of the pumping pipe 123 to detect vibration. As shown, the vibration detection sensor 125 may include a part coupled to the pumping pipe 123 along a direction perpendicular to the vertical direction, and another part coupled along a direction perpendicular to one direction and the vertical direction. there is. Additionally, the vibration detection sensor 125 may form a plurality of layers composed of a plurality of parts arranged at the same height based on the vertical direction. Therefore, vibration occurring in various directions can be detected at various positions by the vibration detection sensor 125. The vibration detection sensor 125 may be a speed sensor that detects vibration by detecting speed, but its type is not limited thereto if it can detect vibration.

Since vibration sensors for monitoring vibration occurring in a vertical pump may have different sensitivities, the vertical pump test device 100 is equipped with vibration analysis equipment (not shown) to precisely detect the vibration detected in the pumping pipe 123. ) can be used to detect vibration. The vibration analysis equipment may be Bently Nevada ADRE, etc., which has a higher sensitivity than the vibration detection sensor 125, but is not limited thereto.

The vibration detection sensor 125 can measure vibration generated by driving the motor 130 in response to changes in physical state. Here, the physical state change of the vertical pump test device 100 refers to the mass imbalance caused by the unbalance plate being installed on the upper part of the motor, the change in the motor 130 and the pumping pipe 123 located inside the motor stand 131. This may mean a state in which misalignment is formed at the rim of the connection portion 135 and a flow of fluid occurs due to the operation of the fluid disturbance device. That is, the connection portion 135 may be a portion where the rim at the bottom of the shaft of the motor and the rim at the top of the pumping pipe 123 come into contact with each other and are coupled to each other by fasteners such as bolts.

The vibration detection sensor 125 can measure mass imbalance generated in the vertical pump test device 100, misalignment at the rim of the connection part 135, and vibration due to the flow of fluid.

The vibration detection sensor 125 can measure vibration that occurs when the motor 130 is driven while an unbalance plate (not shown) is coupled to the top of the motor 130. If an unbalance plate (not shown) is installed on the top of the motor 130, it is possible to analyze changes in vibration generation due to mass imbalance. In addition, the vibration detection sensor 125 is installed with a shim inserted into the rim of the connection part 135 of the motor 130 and the water pipe 123 inside the motor stand 131. Vibration generated by driving the motor 130 in a misalignment state can be measured. Rim misalignment can be formed by changing the screw fastening portion of the rim or changing the fastening strength of the connection portion 135 with the amniotic fluid pipe 123 located inside the motor stand 131. It may be formed by adjusting the bolt fastening between the motor 130 and the pump water pipe 123 inside the motor 130 to cause misalignment.

The vibration detection sensor 125 can measure vibration generated by driving the motor 130 in response to the flow of fluid formed by the operation of the fluid disturbance device 121. The fluid disturbance device 121 forms turbulence that causes fluid instability, and high frequency components in the form of white noise due to cavitation may appear, so it is necessary to properly adjust the fluid disturbance device 121.

In addition, the vibration detection sensor 125 measures vibration when the tightening strength of the bolt fastened to the motor stand 131 is arbitrarily adjusted and the motor 130 and the vertical pump shaft coupling inside the motor 130 are arbitrarily adjusted. can do. Through this, it is possible to analyze the characteristics of vibration generation considering the degree of coupling and adhesion between the components of the vertical pump test device 100.

After measuring vibration due to changes in the physical characteristics of the vertical pump test device 100, the mass of the motor 130 and motor stand 131 is changed, the length and curvature of the pipe 140 are changed, and the rigidity attachment device 160 is installed. Through this, it is possible to test whether resonance occurs in the amniotic fluid pipe 123.

The natural frequency of the vertical pump fixture can be obtained by changing the level of the fluid contained in the water tank 120 and the pumping pipe 123 and analyzing the vibration measured in the pumping pipe 123. Vertical pumps have a relatively high center of gravity and have a low natural frequency, so there is a high risk of resonance due to motor drive. Accordingly, the possibility of resonance is tested by increasing the natural frequency by increasing the mass of the upper part of the motor 130, increasing the mass of the pumping pipe 123, changing the curvature characteristics of the pipe 140, and reinforcing rigidity. You can consider ways to lower it. However, even if the resonance frequency is located above the natural frequency of the vertical pump fixture, resonance occurs when the operating area of the rotating body is 1/2 of the natural frequency, so it is possible to consider ways to avoid this.

That is, through the vertical pump test device 100, after examining the vibration characteristics due to changes in dynamic characteristics, mass imbalance, axial alignment, and vortices of fluid formed in the pipe, which are factors causing high vibration of the rotating part for the vertical pipe, It is possible to identify the main causes of vibration and determine conditions to prevent high vibration and resonance.

Figure 2 is an enlarged view of the upper part of the vertical pump test device 100.

A plurality of motors 130 and motor stands 131 may be installed on the top of the upper frame 111. As shown in FIG. 2, different motors 130 and motor stands 131 may be installed side by side on the top of the upper frame 111. At this time, a rigid additional device 160 for hydraulic pressure adjustment may be installed between each motor stand 131.

The rigid additional device 160 can be installed on one side of the pipe connecting each motor stand 131 and serves to regulate hydraulic pressure. When the hydraulic pressure is adjusted through the rigidity additional device 160, the natural frequency of the vertical pump fixture will change.

A pipe connection portion 161 may be formed to protrude on one side of the motor stand 131 so that the pipe 140 can be inserted and supported. The pipe connection portion 161 may be shaped to surround and support the pipe 140, and may be fixed by fitting after the pipe 140 is inserted.

The pipe 140 may be configured to extend in one direction from the pipe connection portion 161 and then branch in both directions. The pipe 140 may be composed of a first pipe 141 that is bent at a certain curvature from the pipe connection portion 161, and a second pipe 142 that branches off from the first pipe 141 and extends in a straight line. At this time, when the curvature of the first pipe 141 changes, the natural frequency changes due to a change in the characteristics of the pipe itself, so this can be used to limit the occurrence of resonance in the vertical pipe.

The first pipe 141 and the second pipe 142 located in the discharge section connected to the pipe connection 161 on one side of the motor stand 131 are installed in consideration of conditions that generate vortices and smooth fluid flow. , the flow control valve 145 can be opened or closed. For example, when it is necessary to check the pressure and water hammer action of the pipe after the discharge pipe, the first pipe 141 may be closed and the second pipe 142 may be opened. The pressure of the pipe can be sensed through the discharge pressure sensor 147.

In addition, the vibration detection sensor 125 can measure vibration in a mass imbalance state that occurs as the unbalance plate is applied to the imbalance generator 170 at the top of the motor 130, and in the same way, in the impeller or coupling portion. Vibration occurring in a state of mass imbalance can be detected. The imbalance generator 170 is installed on the top of the motor 130 and may have a plurality of bolt holes to facilitate coupling of the imbalance plate. The imbalance generating portion 170 may be formed in a circular shape when viewed downward, and a plurality of bolt holes may be disposed along its circumference. The unbalance plate is formed in a disk shape corresponding to this, and a plurality of bolt holes are formed along the circumference thereof, so that the unbalance plate and the imbalance generating unit 170 can be coupled to each other by bolts.

Figure 3 is a plan view of the vertical pump test device 100.

The vibration detection sensor 125 is installed on the inside of the motor stand 131 by inserting a shim into the rim of the connection part 135 with the positive water pipe 123. It is possible to create misalignment and measure the resulting change in vibration. Additionally, the vibration detection sensor 125 may measure vibration that occurs when misalignment occurs by adjusting the bolt fastening between the motor 130 and the internal pump. At this time, rim misalignment can be formed through a method of arbitrarily adjusting the strength and installation position of the bolt fastening located in the radial direction of the motor stand 131.

The vibration detection sensor 125 can detect vibration that occurs as the motor 130 is driven in a state where mass imbalance occurs due to an unbalance plate being coupled to the imbalance generator 170 installed on the top of the motor 130. Additionally, the vibration detection sensor 125 can detect vibration generated by adjusting the bolt and bearing clearance of the motor stand 131.

The generated vibration can be detected and analyzed through the vibration detection sensor 125, and it is possible to identify the resonance generation mechanism using the vertical pump test device 100, so resonance can be avoided by controlling the high vibration of the rotating body. I do it.

Figure 4 is a partial enlarged view of the lower part of the vertical pump test device 100.

A fluid disturbance device 121 may be installed inside the water tank 120 installed inside the support frame 110. The fluid disturbance device 121 is installed inside the water tank 120 and plays a role in forming fluid vibrations, and may refer to an agitator that forms a flow of fluid. The fluid disturbance device 121 can form turbulence that causes fluid instability. The vibration detection sensor 125 can measure vibration while the flow of fluid generated inside the water tank 120 occurs according to the operation of the fluid disturbance device 121. Through this, changes in the magnitude of vibration according to fluid flow can be examined and considered in designing a vertical pump to prevent high vibration. However, since high-frequency components in the form of white noise may appear due to cavitation, the flow of fluid through the fluid disturbance device 121 must be controlled to continue at appropriate intensity and intensity.

What has been described above is only an embodiment for carrying out the vertical pump test device according to the present invention, and the present invention is not limited to the above embodiments, and the gist of the present invention is summarized as claimed in the following claims. It will be said that the technical idea of the present invention extends to the extent that anyone with ordinary knowledge in the field to which the invention pertains can make various changes without departing from the scope.

100: Vertical pump test device
110: support frame
120: Water tank
130: motor
131: Motor stand
140: Piping
141: 1st pipe
142: Second pipe
145: Flow control valve
160: Rigid attachment device

Claims (7)

A support frame that supports a load and forms a receiving space therein, and an upper frame installed on the support frame;
A water tank installed in the receiving space, containing fluid at a set water level therein, and having a fluid disturbance device installed on the lower surface to generate fluid vibration;
A motor installed on top of the upper frame and a motor stand supporting the motor;
A pipe connecting the inside of the water tank and the motor stand and through which fluid moves along the inside;
A pumping pipe installed at the lower part of the motor stand, containing fluid at a set water level therein, and having one end in communication with the inside of the water tank;
A vibration detection sensor installed on one side of the pumping pipe to measure vibration generated by driving the motor;
an imbalance generator installed at the top of the motor; and
A vertical pump test device including an unbalance plate coupled to the imbalance generator.
delete According to paragraph 1,
A connection portion between the motor and the amniotic fluid pipe; and
A vertical pump test device further comprising a fitting member inserted into the connection portion to cause misalignment of the rim portion of the connection portion.
According to paragraph 1,
A vertical pump test device characterized in that a piping connection part protrudes from one side of the motor stand to support the insertion of a pipe, and the piping connection part extends in one direction and then branches in both directions.
According to paragraph 4,
The pipe includes: a first pipe extending from the pipe connection portion and bent with a constant curvature; and
A vertical pump test device including a second pipe that extends and is separated from the first pipe.
According to paragraph 1,
Different motors and motor stands are installed side by side on the upper part of the upper frame,
A vertical pump test device, characterized in that it further comprises a rigid additional device installed on the pipe connecting the motor stands arranged side by side to adjust the pressure of the fluid flowing inside the pipe.
According to paragraph 1,
A vertical pump test device including vibration analysis equipment for precise detection of vibration occurring when the motor is driven.

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