Self-adaptive frequency error base and frequency error method for high-speed centrifuge

Abstract

The application provides a high-speed centrifuge adaptive frequency error foundation and frequency error method, which is arranged as a two-layer cylindrical structure, the side wall of the cylindrical structure is divided into double layers, and a plurality of upper annular compartments and lower annular compartments are formed. The outer bottom of the annular compartment is provided with a filling and discharging branch pipe, and the filling and discharging branch pipe is connected to a water pump after being collected. The water pump is connected to a water storage pool through an external water pipe. A vibration sensor is installed on the bottom plate of the upper layer, and is transmitted to a collection and processing system through a collection line, so that real-time vibration source frequency domain analysis can be performed, and the water pump is connected to the water pump through a servo control connection line. After being judged by the collection and processing system, the frequency increasing or frequency decreasing program can be triggered, the water pump injects water into the annular compartment, changes the overall gravity center of the foundation, and then increases or decreases the first-order horizontal swing frequency of the foundation, so that the frequency error is realized. The application has the beneficial effects of large frequency conversion range, wide vibration source frequency domain range, good vibration control effect, low engineering cost, simple equipment, easy installation and maintenance, etc.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of large power machine equipment foundation design in civil engineering, and particularly relates to a self-adaptive anti-vibration foundation and a frequency offset method for a high-speed centrifuge. BACKGROUND

[0002] A centrifuge is an important scientific experimental device and is widely used in fields such as geotechnical engineering, earthquake engineering, environmental engineering and earth science. By driving the centrifuge at high speed by a motor, a centrifugal acceleration of several hundred to several thousand times can be generated in a basket to simulate a supergravity environment for scientific experimental research. With the deepening of research needs, the capacity and acceleration of newly-built centrifuges at home and abroad are showing a trend of being larger and larger.

[0003] The centrifuge foundation is a supporting and mounting structure for the centrifuge main machine and the driving motor. Due to the large centrifuge speed and high load, the vibration problem of the foundation structure is very prominent. There are problems of excessive foundation vibration leading to shutdown of the main machine or limitation of use of the working condition at home and abroad. In particular, the large centrifuge has a large operating speed range and a long operating time, resulting in a large range of vibration source frequency. The traditional power machine foundation design method is difficult to meet the frequency offset of the foundation natural frequency and all vibration sources, so that resonance occurs for a long time in some working conditions, causing serious damage to the main machine and structure.

[0004] For the vibration problem caused by a wide frequency vibration source, similar engineering schemes at home and abroad use air springs to design, which can change the natural frequency of the foundation by changing the spring pressure to change the stiffness of the foundation to achieve frequency offset. However, this design scheme has the following problems: (1) the centrifuge foundation is large in scale, and the use of air spring scheme leads to high engineering cost; (2) the air spring mechanism is complex, has a high failure rate, and is difficult to install and maintain. Therefore, it is difficult to promote and apply. SUMMARY

[0005] In order to overcome the shortcomings and deficiencies of the prior art, the present application provides a self-adaptive frequency offset foundation and a frequency offset method for a high-speed centrifuge, which can realize self-adaptive frequency offset, has good anti-vibration effect, and can reduce the engineering cost.

[0006] According to a first aspect of the present application, the technical scheme adopted by the present application is as follows.

[0007] A self-adaptive frequency offset foundation for a high-speed centrifuge is characterized in that: the overall arrangement is a cylindrical structure with two layers, the inside of the cylindrical structure, for the upper layer and the lower layer of the cylindrical structure, is respectively provided with an annular cavity, and the upper layer annular cavity and the lower layer annular cavity are respectively divided into a plurality of upper layer annular compartments and a plurality of lower layer annular compartments.

[0008] Each annular compartment is provided with a charge and discharge branch pipe, the charge and discharge branch pipe is provided with an electric control valve, the charge and discharge branch pipes are connected to a water pump through a charge and discharge main pipe, the charge and discharge main pipe is provided with an electric control valve, and the water pump is connected to a water storage pool through an external water pipe;

[0009] The upper layer bottom plate is provided with a vibration sensor, which is transmitted to a collection processing system through a collection line, the collection processing system compares the vibration source frequency domain in real time, and is connected to the water pump and the electric control valve through a servo control connection line.

[0010] On the basis of the above technical scheme, the application can also use the following further technical schemes, which will be combined with these further technical schemes:

[0011] The annular cavity is provided with a partition structure, forming a plurality of upper annular compartments and lower annular compartments.

[0012] The charge and discharge branch pipe corresponds to the annular compartment one by one.

[0013] The upper annular compartments and the lower annular compartments are internally provided with energy dissipation grids, and the compartment walls and the bottoms of the upper annular compartments and the lower annular compartments are provided with protrusions.

[0014] According to the second aspect of the application, the application adopts the technical scheme as follows.

[0015] A self-adaptive frequency error method of a high-speed centrifuge foundation, the implementation method is: through calculation and analysis, the first-order horizontal swing natural frequency f of the foundation in the initial state of the upper annular compartment and the lower annular compartment being empty is obtained d ; when the upper annular compartment is filled, the overall horizontal swing natural frequency of the foundation is denoted as f d-low ; when the lower annular compartment is filled, the overall horizontal swing natural frequency of the foundation is denoted as f d-high , then the first-order natural frequency frequency variation range of the self-adaptive frequency error foundation of the high-speed centrifuge is:

[0016] f d-low ≤f d ≤f d-high

[0017] The vibration signal measured by the vibration sensor is transmitted to the collection processing system and subjected to frequency spectrum analysis to obtain the vibration source main frequency f of the current working condition s ; the collection processing system compares and discriminates,

[0018] When f d and f s satisfy 0.8f s ≤f d ≤1.2f sIf f < f0, it is considered that the inherent frequency of the foundation cannot meet the demand of the frequency error, and the acquisition processing system triggers the frequency conversion control, which includes two implementation methods of frequency reduction and frequency increase; when frequency reduction is needed, the water quantity of the upper annular compartment is increased relative to the water quantity of the lower annular compartment; when frequency increase is needed, the water quantity of the lower annular compartment is increased relative to the water quantity of the upper annular compartment.

[0019] Further, the acquisition processing system controls the water pump, the filling and discharging main pipe, the filling and discharging branch pipe and the electric control valve through the servo control connection line; when frequency reduction is needed to realize the frequency error, water is pumped from the water storage pool and injected into the upper annular compartment through the filling and discharging main pipe and the filling and discharging branch pipe; after the upper annular compartment is filled with water, the overall center of gravity of the foundation is increased, so that the inherent frequency of the overall horizontal swing of the foundation is reduced until f d <0.8f s At this time, the upper annular compartment is completely filled with water and the lower annular compartment is completely emptied.

[0020] Further, the acquisition processing system controls the water pump, the filling and discharging main pipe, the filling and discharging branch pipe and the electric control valve through the servo control connection line; when frequency increase is needed to realize the frequency error, water is pumped from the water storage pool and injected into the lower annular compartment through the filling and discharging main pipe and the filling and discharging branch pipe, and after the lower annular compartment is filled with water, the overall center of gravity of the foundation is reduced, so that the inherent frequency of the overall horizontal swing of the foundation is increased until f d >1.2f s , the frequency error is realized.

[0021] As a preferred technical scheme of the present application, the self-adaptive frequency error foundation of the high-speed centrifuge is a buried foundation structure embedded in bedrock.

[0022] The self-adaptive frequency error foundation of the high-speed centrifuge and the implementation method thereof have the following beneficial effects:

[0023] (1) The inherent frequency of the foundation has a large variation range, and the applicable main machine vibration source frequency domain range is wide;

[0024] (2) The foundation realizes the frequency error at the same time, and the vibration control effect is good by increasing the water body to increase the vibration resistance mass of the foundation;

[0025] (3) The self-adaptive frequency error device is simple, reduces the engineering cost, and is easy to install and maintain. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 It is a typical example of a cross-sectional view of a self-adaptive frequency error foundation of a high-speed centrifuge.

[0027] Figure 2 It is Figure 1 A top view of a self-adaptive frequency error foundation of a medium and high-speed centrifuge.

[0028] Figure 3 Flow chart for adaptive frequency modulation of the embodiment of the present application.

[0029] Figure 4 Schematic diagram for frequency reduction of the embodiment of the present application.

[0030] Figure 5 Schematic diagram for frequency increase of the embodiment of the present application.

[0031] Reference numerals: 1 - centrifuge main machine, 2 - driving motor, 3 - upper layer bottom plate, 4 - lower layer bottom plate, 5 - side wall, 6 - partition plate, 7 - upper layer annular partition compartment, 8 - lower layer annular partition compartment, 9 - filling and discharging branch pipe, 10 - electric control valve, 11 - filling and discharging main pipe, 12 - electric control main valve, 13 - water pump, 14 - external water pipe, 15 - water storage tank, 16 - vibration sensor, 17 - acquisition circuit, 18 - acquisition processing system, 19 - servo control connection circuit, 20 - energy dissipation grid, 21 - protrusion. DETAILED DESCRIPTION

[0032] The present application will be further described in detail below in combination with the drawings and embodiments:

[0033] As shown in Figure 1 and 2 , the high-speed centrifuge adaptive frequency modulation provided by the present application has an overall arrangement of a cylindrical structure with two layers, the upper layer bottom plate 3 is used for installing the centrifuge main machine 1, and the lower layer bottom plate 4 is used for installing the driving motor 2 and other equipment. The side wall 5 of the cylindrical structure is internally provided with an annular cavity, and a plurality of partition plates 6 are arranged in the annular cavity to form a plurality of upper layer annular partition compartments 7 corresponding to the upper layer and a plurality of lower layer annular partition compartments 8 corresponding to the lower layer. The outer bottom of the annular partition compartments 7, 8 is provided with filling and discharging branch pipes 9, each of which is provided with an electric control valve 10, and all the filling and discharging branch pipes 9 are connected to the water pump 13 through the filling and discharging main pipe 11 after being collected, and the electric control main valve 12 is arranged on the filling and discharging main pipe 11. The water pump 13 is connected to the water storage tank 15 through the external water pipe 14. The upper layer bottom plate 3 is provided with a vibration sensor 16, which is transmitted to the acquisition processing system 18 through the acquisition circuit 17, and the acquisition processing system 18 can perform real-time vibration source frequency domain analysis. The acquisition processing system can be a computer connected to the water pump 13 and the electric control valve 10 through the servo control connection circuit 19 to control the operation of the water pump 13 and each electric control valve 10.

[0034] The upper and lower annular compartments 7 and 8 are internally provided with energy dissipation grids 20, which are structured as perforated steel plates; the compartment walls or bottoms of the upper and lower annular compartments 7 and 8 are provided with protrusions 21, which can be structured as four-pyramid-shaped concrete structures; the energy dissipation grids 20 and the protrusions 21 serve to dissipate energy.

[0035] For the adaptive mistuning foundation of the high-speed centrifuge in the present embodiment, the first-order horizontal swing natural frequency f d of the adaptive mistuning foundation of the high-speed centrifuge in the present embodiment is 6.0 Hz, the first-order horizontal swing natural frequency f d-low of the adaptive mistuning foundation of the high-speed centrifuge in the present embodiment is 4.2 Hz, and the first-order horizontal swing natural frequency f d-high of the adaptive mistuning foundation of the high-speed centrifuge in the present embodiment is 6.6 Hz, and thus the first-order natural frequency frequency range of the adaptive mistuning foundation of the high-speed centrifuge is:

[0036] 4.2 Hz ≤ f d ≤ 6.6 Hz (4)

[0037] As can be seen therefrom, filling the upper annular compartment 7 is a frequency reduction adjustment behavior, filling the lower annular compartment 8 is a frequency increase adjustment behavior, and dividing the upper annular compartment 7 and the lower annular compartment 8 into multiple layers can achieve step-by-step adjustment.

[0038] For the vibration sources of various centrifuge operating conditions, the following implementation method is adopted:

[0039] When f s < 5.0 Hz, frequency conversion is not needed;

[0040] When 5.0 Hz ≤ f s < 5.25 Hz, a frequency increase program is triggered, and the water pump 13 fills the lower annular compartment 8 with water;

[0041] When 5.25 Hz ≤ f s < 7.5 Hz, a frequency reduction program is triggered, and the water pump 13 fills the upper annular compartment 7 with water;

[0042] When f s > 7.5 Hz, frequency conversion is not needed.

[0043] Referring to Figure 3 , 4 , 5, the implementation method of an adaptive mistuning foundation of a high-speed centrifuge will be described below by means of three embodiments.

[0044] (a) When the centrifuge main unit 1 is running in working condition 1, the vibration source main frequency f is measured by the vibration sensor 16 and the acquisition and processing system 18. s is 8.0 Hz, then the acquisition and processing system 18 determines that f d <0.8f s , meeting the frequency error condition, no frequency conversion is required.

[0045] Analysis shows that when the operating conditions of the centrifuge host 1 make the main frequency of the vibration source meet

[0046] f s <5.0Hz or f s >7.5Hz(5)

[0047] No frequency conversion is required.

[0048] (b) When the centrifuge main unit 1 is running in the second working condition, the vibration source main frequency f is measured by the vibration sensor 16 and the acquisition and processing system 18. s is 7.5Hz, then the acquisition and processing system 18 determines that 0.8f s ≤f d ≤1.2f s , the frequency error condition is not met, then the acquisition and processing system 18 triggers the frequency reduction program. The acquisition and processing system 18 controls the water pump 13, the electric control main valve 12 and the electric control valve 10 through the servo control connection line 19 to pump water from the water tank 15 and inject it into the upper annular compartment 7 through the charging and discharging main pipe 11 and the charging and discharging branch pipe 9. After the upper annular compartment 7 is filled with water, the first-order horizontal oscillation natural frequency f d-low is 4.2Hz to meet f d <0.8f s , to achieve frequency error, such as Figure 4 shown.

[0049] (c) When the centrifuge main unit 1 is running in working condition 3, the vibration source main frequency f is measured by the vibration sensor 16 and the acquisition and processing system 18. s is 5.0Hz, then the acquisition and processing system 18 determines that 0.8f s ≤f d ≤1.2f s , the frequency error condition is not met, then the acquisition and processing system 18 triggers the frequency increase program. The acquisition and processing system 18 controls the water pump 13, the electric control main valve 12 and the electric control branch valve 10 through the servo control connection line 19 to pump water from the water tank 15 and inject it into the lower annular compartment 8 through the charging and discharging main pipe 11 and the charging and discharging branch pipe 9. After the lower annular compartment 8 is filled with water, the first-order horizontal oscillation natural frequency f d-high is 6.6Hz, satisfying f d> 1.2f s , a frequency error is realized, as Figure 5 indicated.

[0050] The above description is only to illustrate specific embodiments of the present application, and is not intended to limit the scope of the application. Any equivalent changes or modifications made by those skilled in the art without departing from the spirit and principles of the present application shall be covered by the scope of the claims of the present application.

Claims

1. A frequency staggering method based on adaptive frequency staggering for a high-speed centrifuge, characterized by: The overall layout of the high-speed centrifuge adaptive staggered frequency foundation is a two-layer cylindrical structure. Inside the side wall of the cylindrical structure, annular cavities are respectively provided for the upper and lower layers of the cylindrical structure. The upper annular cavity and the lower annular cavity are respectively divided into multiple layers of upper annular compartments and multiple layers of lower annular compartments. Each annular compartment is provided with a charging and discharging branch pipe, which is provided with an electric control valve. The charging and discharging branch pipes are connected to the water pump through the charging and discharging main pipe after being collected. The charging and discharging main pipe is provided with an electric control main valve. The water pump is connected to the water tank through an external water pipe. The upper floor is equipped with a vibration sensor, which transmits the vibration to the acquisition and processing system through the acquisition line. The acquisition and processing system performs real-time frequency domain comparison of the vibration source and is connected to the water pump and the electric control valve through the servo control connection line; The implementation method of the frequency stagger method is: through calculation and analysis, the first-order horizontal oscillation natural frequency f of the foundation in the initial state where the upper annular compartment and the lower annular compartment are empty is obtained. d When the upper annular compartment is filled, the natural frequency of the overall horizontal swing of the foundation is recorded as f d-low When the lower annular compartment is filled, the natural frequency of the overall horizontal swing of the foundation is recorded as f d-high , then the first-order natural frequency conversion range of the high-speed centrifuge's adaptive staggered frequency basis is: f d-low ≤f d ≤f d-high The vibration signal measured by the vibration sensor is transmitted to the acquisition and processing system, and the main frequency f of the vibration source under the current working condition is obtained through spectrum analysis. s ; After comparison and judgment, the acquisition and processing system When f d and f s Satisfy 0.8f s ≤f d ≤1.2f s , it is considered that the basic natural frequency cannot meet the frequency error requirement, and the acquisition and processing system triggers the frequency conversion control, which includes two implementation methods: frequency reduction and frequency increase; when frequency reduction is required, the water volume of the upper annular compartment is increased relative to the water volume of the lower annular compartment; when frequency increase is required, the water volume of the lower annular compartment is increased relative to the water volume of the upper annular compartment.

2. A frequency error method for a high-speed centrifuge adaptive frequency error basis according to claim 1, characterized in that: the acquisition and processing system controls the water pump, the electric control main valve on the charge and discharge main pipe, and the electric control valve on the charge and discharge branch pipe through a servo control connection line. When frequency reduction is required to achieve frequency error, water is pumped from the water tank and injected into the upper annular compartment through the charge and discharge main pipe and the charge and discharge branch pipe. After the upper annular compartment is filled with water, the overall center of gravity of the foundation is increased, so that the overall horizontal swing natural frequency of the foundation is reduced until f d <0.8f s .

3. A frequency error method for a high-speed centrifuge adaptive frequency error basis according to claim 1, characterized in that: the acquisition and processing system controls the water pump, the electric control main valve on the charge and discharge main pipe, and the electric control valve on the charge and discharge branch pipe through a servo control connection line. When frequency increase is required to achieve frequency error, water is pumped from the water tank and injected into the lower annular compartment through the charge and discharge main pipe and the charge and discharge branch pipe. After the lower annular compartment is filled with water, the overall center of gravity of the foundation is lowered, so that the overall horizontal swing natural frequency of the foundation increases until f d >1.2f s .

4. The frequency staggering method based on the adaptive frequency staggering of a high-speed centrifuge according to claim 1, characterized in that: A partition structure is arranged in the annular cavity to form a plurality of upper annular partitions and lower annular partitions.

5. The frequency staggering method based on the adaptive frequency staggering of a high-speed centrifuge according to claim 1, characterized in that: The charging and discharging branch pipes correspond to the annular compartments one by one.

6. The frequency staggering method based on adaptive frequency staggering of a high-speed centrifuge according to claim 1, characterized in that: Energy dissipation grids are installed inside the upper annular partition and the lower annular partition, and protrusions are provided on the walls and bottoms of the upper annular partition and the lower annular partition.

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