CN104634266A - Mechanical sealing end surface deformation measurement system based on binocular vision DIC and measurement method thereof - Google Patents

Abstract

The invention discloses a mechanical sealing end surface deformation measurement system based on binocular vision DIC and a measurement method thereof. The system comprises a mechanical sealing test device, high-speed digital cameras, lenses, acquisition cards, a light source, a calibration plate, a support system, and a server for digital image acquisition and correlation analysis and processing. The measurement method altogether comprises eight steps. A speckle image on the surface of a mechanical sealing static ring in an operation condition can be acquired, the image can be analyzed and processed by directly using the binocular vision digital image correlation method, and thus, a three-dimensional shape on the surface of the mechanical sealing static ring, and a three-dimensional deformation field under effects of force and thermal load can be acquired. According to the method, the use is convenient, the measurement precision is high, the full-filed measurement problem of surface deformation under effects of force and thermal load of mechanical sealing can be effectively solve4d, and foundation is laid for making a research on key factors influencing mechanical sealing deformation and exploring measures for reducing deformation.

Description

A kind of based on binocular vision DIC mechanical seal end surface deformation measuring system and measuring method thereof

Technical field

The present invention relates to a kind of measuring system for the whole audience 3 D deformation under mechanical seal end surface three-dimensional appearance and power, Thermal Load and measuring method, belong to the fields such as optical measurement mechanics, mechanical seal displacement and deformation test technology.

Background technology

Mechanical seal need not adjust because having in good airproof performance, long service life, running, power attenuation is little, axle or boss surfaces is not easy to wear, resistance to vibration is strong, seal parameters advantages of higher, and is widely used in the sealing of turning axle in the commercial units such as machinery, oil, chemical industry, electric power, light industry, boats and ships, aerospace and atomic energy.

Mechanical seal is generally by sealing pair (rotating ring 4 and stationary ring 5), the primary element composition such as flexible member (spring 2 or corrugated tube), rotating ring auxiliary seal (O shape circle 3), stationary ring auxiliary seal (O shape circle 6), driving member (beam barrel 1), rotation preventing device (stationary seat 7), as shown in Figure 1.Rotating ring and loading spring are installed in rotating seat, and rely on O shape circle to carry out secondary seal.Rotating ring relies on axle sleeve fix on the rotary shaft and rotate with the axis.Rotating ring, under the effect of the load such as spring force, can move freely vertically, and keeps the close contact of rotating ring and stationary ring end face.According to actual requirement, flexible member also can be arranged on stationary seat.Therefore, mechanical seal is that a kind of flexible member that relies on jointly compresses the pretension of rotating ring and stationary ring end face or pressure medium and flexible member and reaches the axial end packoff of sealing.

In practical work process, have several factors directly can have influence on leakage and the life-span of sealing, one of them key factor is that mechanical seal in use keeps the parallel or approximately parallel ability of seal face geometric configuration.That is, geometric configuration under any circumstance all necessary keeping parallelism or the less parallel in seal face gap, could fully ensure that sealing have excellent performance.But sealing ring, under the effect of mechanical force, thermal force, is asked to be formed at end face and dispersed or the gap of convergence type, cause to leak and increase, wearing and tearing aggravation, the lost of life, has had a strong impact on the result of use of sealing.Therefore accurate Calculation machinery seal face is out of shape, the key factor of research impact distortion, and the measure exploring Reducing distortion has important directive significance to improving mechanical seal sealing property and serviceable life and developing mechanical sealed product.

Along with mechanical sealing technology to high pressure, at a high speed, the future development such as high temperature and major diameter, the problem on deformation of mechanical seal ring is just particularly outstanding.At present, both at home and abroad about the research work of Mechanical Seal Temperature Field and sealing ring deformation mainly concentrates on theoretical analysis and numerical method, comparatively ripe analytical solution mainly contains annulus theory and finite element method.Analytical method is the most accurate a kind of in mechanical seal end surface Method for Calculating Deformation, but is only suitable for the situation that sealed section is simple shape.Its shortcoming is that calculating is loaded down with trivial details, is not suitable for engineering reality.Finite element method is the current method using computer research mechanical seal distortion preferably, use the theory of thermal-structure coupled steady-state analysis can be applied on model by thermal force according to the Force Calculation heat of friction of end face, computing while achieving structure analysis and thermal analyses result.Finite element method is very large as comparatively effective deformation analysis method development potentiality.Numerical method is different from physical model experiment, cannot provide the quantitative description of required problem when starting.It needs physical experiments to provide relation between some parameter and parameter, near and set up the mathematical model meeting required problem.Its application also depends on the analysis of theory, the judgement of experience and final verification experimental verification.Although a large amount of experimental study of mechanical seal starts from the sixties in 20th century, mainly concentrate on about mechanical seal experimental study: 1. study the operating parameters such as the temperature and pressure of medium, spring pressure, rotating speed to mechanical sealing performance and the impact in serviceable life; 2. by the moment of torsion of sensor measurement sealing ring end face, temperature, face pressure and thickness of liquid film etc., the rubbing characteristics of research different condition lower seal end face and on sealing characteristics and the impact in serviceable life.And carry out also less about the Test And Research Work of direct mechanical seal face distortion, and face deformation test adopts resistor straining testing method, although method of testing is a kind of very ripe mechanical measuring and calculation method in this, but the method is measured as basis with point, can not obtain the deformation signal of the whole audience, and measuring process is comparatively loaded down with trivial details, detecting the feeble signal obtained exists by situations such as noise are serious, signal very easily deforms, and distortion is serious, and measurement result differs larger with real work situation.Binocular vision Digital Image Correlation Method (DIC), it is a kind of photo-measuring experimental mechanics method of a kind of full field deformation measure that development in recent years is got up, as compared to other measuring methods (moiréinterferometry and Electronic Speckle Pattern Interferometry), have measuring system and measuring process simple, without the need to LASER Light Source, to measurement environment require low, be suitable for the advantages such as complex-shaped object, achieve suitable success in technical field of measurement and test, show huge potentiality.For overcoming resistor straining testing method shortcoming, development based on inheritance binocular vision Digital Image Correlation Method advantage, the invention provides a kind of measurement of full field method that mechanical seal end surface of being correlated with based on binocular vision digital picture is out of shape.

Summary of the invention

Object of the present invention is intended to for overcoming the deficiencies in the prior art, and provide a kind of based on binocular vision DIC mechanical seal end surface deformation measuring system and measuring method, this systems approach effectively can solve the measurement of full field problem of the face deformation of mechanical seal under power, Thermal Load, has simple in measurement system structure, easy to use, measuring accuracy advantages of higher.

Technical scheme of the present invention is as follows:

A kind of based on binocular vision DIC mechanical seal end surface deformation measuring system, it comprises mechanical seal test device, high-speed digital photography machine, camera lens, capture card, light source, scaling board, mounting system and the computing machine for digital image acquisition and correlation analysis process; Its position order of connection is: high-speed digital photography machine screw is arranged in square box, has bolt hole immediately below square box, is fixed on translation stage by bolt by square box, and translation stage is arranged on the guide rail on tripod; To regulate under square box angle and distance between square bolt adjustable two high-speed digital photography machine; According to height and the orientation of test specimen, by height and the luffing angle of tripod adjustment high-speed digital photography machine; High-speed digital photography machine is connected with capture card by data line, and capture card is installed on the server; Light source, between two high-speed digital photography machines, installs camera lens before high-speed digital photography machine, by adjustable lens focal length and aperture, can clearly photograph image mechanical seal test device being measured test specimen.

Described mechanical seal test device cavity material is tempered glass, can commercially choose as requested;

Described high-speed digital photography machine, its speed and resolution are determined according to measurement rotating speed and precision, can commercially choose as requested;

Described camera lens, selectes according to test specimen size and high-speed digital photography machine, can commercially choose as requested;

Described capture card, selectes according to high-speed digital photography machine, can commercially choose as requested;

Described light source is monochromatic cold light source, can commercially choose as requested;

Described scaling board, determines its physical dimension according to test specimen size, is round dot gridiron pattern, can makes by oneself;

Described square box, determines its physical dimension according to high-speed digital photography machine size, can make by oneself;

Described tripod is the special tripod of industrial camera, can commercially choose as requested;

Described translation stage is that elongated hole is opened in square centre, self-control;

Described computing machine is server.

Wherein, the quantity of high-speed digital photography machine is 2;

Wherein, the quantity of camera lens is 2;

Wherein, the quantity of capture card is 2.

Based on a measuring method for binocular vision DIC mechanical seal end surface deformation measuring system, concrete measuring process is as follows:

(1) adopt mechanical sealing static ring as test sample;

(2) mode of surperficial random spray black and white paint is adopted to make speckle pattern;

(3) test sample is installed to implementation on Mechanical Seal Testing Machine to load;

(4) measuring system is faced test sample on testing machine to place;

(5) adopt monochromatic illumination light source evenly to shine tested sample, adjustable lens focal length and aperture are until camera blur-free imaging;

(6) scaling board is adopted to demarcate the inside and outside portion parameter of two digital cameras;

(7) under the forward and backward different conditions of test piece deformation, its speckle image is absorbed respectively with left and right high-speed digital photography machine, as the analysis chart picture that binocular vision digital picture is relevant;

(8) the forward and backward surface topography of sample deformation and whole field deformation is calculated by binocular vision Digital Image Correlation Method.

Beneficial effect of the present invention is as follows:

(1) advanced digital image correlation technique is used to test mechanical seal end surface distortion, make test environment close to mechanical seal normal operation circumstances, avoid resistor straining testing method with a measurement shortcoming, achieve the measurement of full field of mechanical seal end surface distortion.

(2) whole field deformation according to actual measurement mechanical seal end surface studies the key factor affecting distortion, explore the measure of Reducing distortion, effectively can instruct the design of mechanical seal, manufacture, use technology, thus improve mechanical seal sealing property and serviceable life, reduce mechanical seal and to lose efficacy the energy, waste of raw materials and the casualties that cause.

Accompanying drawing explanation

Fig. 1 is mechanical seal basic structure and binocular vision Digital-image correlation method system schematic.

Fig. 2 is binocular vision Digital Image Correlation Method schematic diagram.

Fig. 3 is the process flow diagram utilizing binocular vision Digital Image Correlation Method to measure body surface distortion.

In figure, symbol description is as follows:

1 sleeve, 2 springs, 3 rotating ring O shape circles, 4 rotating rings, 5 stationary rings, 6 stationary ring O shape circles, 7 stationary seats, 8 seal chambers, 9 left high-speed digital photography machines, 10 left camera lenses, 11 left boxes, 12 right camera lenses, 13 right high-speed digital photography machines, 14 right boxes, 15 translation stages, 16 light sources, 17 computing machines, 18,19 capture cards, 20 scaling boards.

Embodiment

Concrete structure of the present invention and embodiment is further illustrated below in conjunction with accompanying drawing 1:

Measuring system structure of the present invention as shown in Figure 1, whole system is by left high-speed digital photography machine 9, right high-speed digital photography machine 13, left camera lens 10, right camera lens 12, capture card 18,19, light source 16, scaling board 20, mounting system (square box 11,14, translation stage 15), computing machine 17 and mechanical seal test device composition.

Its position order of connection is: left and right high-speed digital photography machine 9,13 screw is arranged on square box 11,14 li respectively, bolt hole is had immediately below square box 11,14, be fixed on translation stage 15 by bolt by square box 11,14, translation stage 15 is arranged on the guide rail on tripod; Regulate angle and distance between the left and right high-speed digital photography machine 9,13 of square box 11,14 times square bolt adjustable; According to height and the orientation of test specimen, adjusted height and the luffing angle of left and right high-speed digital photography machine 9,13 by tripod; Left and right high-speed digital photography machine 9,13 is connected with capture card 18,19 respectively by data line, and capture card 18,19 is arranged on computing machine 17; Light source 16 is between left and right high-speed digital photography machine 9,13, before left and right high-speed digital photography machine 9,13, camera lens 10,12 is installed respectively, by focal length and the aperture of adjustable lens 10,12, the image of stationary ring 6 on mechanical seal test device clearly can be photographed.

Described mechanical seal test device cavity 8 is tempered glass; That left and right high-speed digital photography machine 9,13 is chosen is German BaslerA504K; That described camera lens 10,12 is chosen is Pentax YF5028; That described capture card 18,19 is chosen is Matrox MIL-Lite9.0; The green LED lamp of what described light source 16 was chosen is wavelength X=520-550nm; What described computing machine 17 was chosen is server.

Wherein, the quantity of high-speed digital photography machine 9,13 is 2;

Wherein, the quantity of camera lens 10,12 is 2;

Wherein, the quantity of capture card 18,19 is 2.

Based on a measuring method for binocular vision DIC mechanical seal end surface deformation measuring system, concrete measuring process is as follows:

(1) adopt GY70 type mechanical sealing static ring as test sample 6, its material is leaching furane resin carbon graphite M106K;

(2) mode of surperficial random spray black and white paint is adopted to make speckle pattern, its average gray gradient (Pan Bing, Wu great Fang, Xia Yong. quality assessment research [J] of speckle pattern in Digital Image Correlation Method. Experimental Mechanics, 2010,25 (2): 120 ~ 129) about 39 are reached;

Sensor zero setting;

(4) measuring system is faced test sample 6 on testing machine to place;

(5) open LED 16 evenly according to tested sample 6, adjustable lens 10,12 focal length and aperture are until left and right high-speed digital photography machine 9,13 blur-free imaging;

(6) with left, right high-speed digital photography machine 9, 13 round dot chessboard calibration plate 20 images simultaneously taking the above different azimuth of three width, utilize software Zhang standardization (Zhang Zhengyou.A flexible new technique for camera calibration [J] .IEEE Transactions on Pattern Analysis and Machine Itelligence, 2000, 22 (11): 1330 ~ 1334.) and Nonlinear Least Squares Method (Tsai R Y. A versatile camera Calibration technique for high-accuracy3D machine vision metrology using off-the-shelf TV cameras and lenses [J] .IEEE Journal ofRobotics and Automation, 1987, ra-3 (4): 323 ~ 344.), calculate a left side, right high-speed digital photography machine 9, in 13, external parameter,

(7) click " collection " button in measuring system, gather test specimen, speckle pattern when not loaded.Drive single coordinate guide rail, make sealing ring be in impaction state.Close annular seal space, check the connection status of medium circulation pipeline, open each valve, start ebullator, test(ing) medium pressurizes.Check each tie point sealing condition.Given closing force, adjustment guide rail position.The setting speed of mainshaft, starts spindle motor, gathers test specimen speckle pattern after loading after stable;

(8) binocular vision Digital Image Correlation Method is utilized to calculate the forward and backward surface topography of sample deformation and whole field deformation.After demarcation is completed to two video cameras, obtain their inside and outside parameter, also establish a spatial world coordinate system based on calibrating template simultaneously, at this moment just can carry out reconstruction of three-dimensional volume coordinate from the two dimensional image coordinate of the corresponding pixel points the image of two camera records.To repetition said process multiple in reference picture, just can obtain several spatial point coordinates, and three-dimensional appearance is exactly in fact abundant spatial point directly forms or form after surface fitting.

Fig. 2 is binocular vision Digital Image Correlation Method schematic diagram.Fig. 3 is the process flow diagram utilizing binocular vision Digital Image Correlation Method to measure body surface distortion.From Fig. 2 and Fig. 3, in the image of left video camera before being deformed, select the image subsection P that will calculate ₁, and the relevant position P in the image of its right video camera is before being deformed found by relevant matches ₂, before calculating testee surface deformation according to principle of triangulation, put the volume coordinate of P (x, y, z).In like manner, its relevant position P is also tracked in the digital picture of left video camera, right video camera after deformation ₁' and P ₂', then after calculating testee surface deformation by principle of triangulation, put P ' (x ' y ', z ').Finally obtain P (x, y, z), P ' (x ', y ', z ') and testee distortion u, v and w can be tried to achieve in formula (1) ~ (3) according to measuring.

$u(x,y,z)=u+\frac{\∂u}{\∂x}\mathrm{\Δx}+\frac{\∂u}{\∂y}\mathrm{\Δy}+\frac{\∂u}{\∂z}\mathrm{\Δz}---\left(1\right)$

$v(x,y)=v+\frac{\∂v}{\∂x}\mathrm{\Δx}+\frac{\∂v}{\∂y}\mathrm{\Δy}+\frac{\∂v}{\∂z}\mathrm{\Δz}---\left(2\right)$

$w(x,y)=w+\frac{\∂w}{\∂x}\mathrm{\Δx}+\frac{\∂w}{\∂y}\mathrm{\Δy}+\frac{\∂w}{\∂z}\mathrm{\Δz}---\left(3\right)$ 。

Claims (5)

1. based on a binocular vision DIC mechanical seal end surface deformation measuring system, it is characterized in that: it comprises mechanical seal test device, high-speed digital photography machine, camera lens, capture card, light source, scaling board, mounting system and the computing machine for digital image acquisition and correlation analysis process; Its position order of connection is: high-speed digital photography machine screw is arranged in square box, has bolt hole immediately below square box, is fixed on translation stage by bolt by square box, and translation stage is arranged on the guide rail on tripod; To regulate under square box angle and distance between square bolt adjustable two high-speed digital photography machine; According to height and the orientation of test specimen, by height and the luffing angle of tripod adjustment high-speed digital photography machine; High-speed digital photography machine is connected with capture card by data line, and capture card is installed on the server; Light source, between two high-speed digital photography machines, installs camera lens before high-speed digital photography machine, by adjustable lens focal length and aperture, clearly can photograph the image measuring test specimen.

2. press one according to claim 1 based on binocular vision DIC mechanical seal end surface deformation measuring system, it is characterized in that: the quantity of high-speed digital photography machine is 2, its speed and resolution are determined according to measurement rotating speed and precision.

3. press one according to claim 1 based on binocular vision DIC mechanical seal end surface deformation measuring system, it is characterized in that: capture card quantity is 2, select according to high-speed digital photography machine.

4. press one according to claim 1 based on binocular vision DIC mechanical seal end surface deformation measuring system, it is characterized in that: the seal chamber of mechanical seal test device is tempered glass.

5., based on a measuring method for binocular vision DIC mechanical seal end surface deformation measuring system, it is characterized in that comprising the following steps:

(1) adopt mechanical sealing static ring as test sample;

(2) mode of surperficial random spray black and white paint is adopted to make speckle pattern;

(3) test sample is installed to implementation on Mechanical Seal Testing Machine to load;

(4) measuring system is faced test sample on testing machine to place;

(5) adopt monochromatic illumination light source evenly to shine tested sample, adjustable lens focal length and aperture are until camera blur-free imaging;

(6) scaling board is adopted to demarcate the inside and outside portion parameter of two digital cameras;

(7) under the forward and backward different conditions of test piece deformation, its speckle image is absorbed respectively with left and right high-speed digital photography machine, as the analysis chart picture that binocular vision digital picture is relevant;

(8) the forward and backward surface topography of sample deformation and whole field deformation is calculated by binocular vision Digital Image Correlation Method.