SK114098A3 - Method and device for checking oil polution of solid surfaces - Google Patents

Abstract

Controlling method of organic contamination of the solid surfaces is performed through the fluorescent detection, without necessity to reduce the lighting from the surroundings, controlled surfaces, visible by light during measuring. Devices for controlling the oil contamination, providing ultraviolet radiation in the form of impulses, synchronised with the closing of digital CCD camera, able to evaluate the amount and locality of fluorescent contaminating substances on the solid surface, suitable for searching for oils and for controlling the surface after deoiling and degreasing.

Description

Method and equipment for controlling the oil contamination of solid surfaces.

Technical field

The present invention relates to a method and apparatus for quantitatively and qualitatively assessing the amount of oil on a solid surface, using a non-contact optoelectronic method that allows operative operational or laboratory control, and solves the problem of assessing the presence and amount of oil on a solid surface, lifetime of degreasing fillings of technological equipment, efficiency of degreasing agents and equipment.

BACKGROUND OF THE INVENTION

So far known methods for assessing the quality of degreasing of solid surfaces either do not allow for operational control or are of low sensitivity and cost. In the case of a highly sensitive method of measurement, the individual sectors of the metalworking, electrical engineering, glass and other industries rely on statistical evaluation of the degreasing quality by destructive methods or indirect evaluation of the quality of the degreasing process.

The evaluation of the de-oiling and degreasing quality of the metal surface prior to paint application is carried out by statistical evaluation according to STN 03 8221 by contact destructive analysis by grid test, which does not allow to distinguish wrongly applied paint, low roughness or poor surface degreasing. At the same time, the disadvantage is that the grid test method has a general limitation on measurement efficiency.

Similarly, in the case of electroplating, the quality of the de-oiling and degreasing is evaluated according to the result of the following operation, the strength and the thickness of the deposited layer of the respective galvanic bath metal.

Assessment of degreasing quality before vacuum quenching is carried out statistically by test of continuous water film failure according to STN 03 8215. The test is unsuitable for more complex shaped surfaces of metal parts.

Another example for indirect assessment of degreasing of metal surfaces is degreasing before welding. The evaluation is carried out only after welding, namely by rengen evaluation of welds flawlessness, especially for nuclear power, according to Russian regulations PNAEG PK 1514-72. The actual evaluation is then performed statistically on the ratio of the number of flawless welds to the total number of welded pieces.

The degreasing control for partially closed systems is performed by means of a gravimetric evaluation of the evaporator, according to STN 03 8215. From the defined amount of volatile solvent, by which the closed system is flushed, the solvent is allowed to evaporate and the residue after evaporation is evaluated by weighing.

MILJOLTEKNIK patent WO 9114935 describes a method for controlling the oil contamination of a metal surface by light interference from a laser source. The disadvantage of this method is low sensitivity and local measurement.

Similarly, EP 0604336 discloses a method for measuring parts of a soiling by means of light reflection, using an optical sensor to determine the exact position of the soiling. The disadvantage of this solution is low measurement sensitivity. In order to determine contamination, the respective grease must form a continuous glossy film. Another disadvantage is the limited number of measurable pollution types.

The method and the device for measuring the pollution are dealt with in patent WO 9524635, which uses the application of labeling radioactive substances which are added to the polluting mixtures in a previous technological operation. This is done by measuring the intensity of radiation, while avoiding the effects of natural background. The disadvantage of this methodology is its limited usability and high cost.

The indirect evaluation method is dealt with in patent WO 9518368 from VOLVO, which solves the problem of evaluating the quality of cleaning and degreasing by measuring the oil content of the cleaning liquid. Its amount is gradually increasing during degreasing and it is assumed that the quality of cleaning is equivalent. The check does not address the identification of local contamination.

Fluorescence evaluation of the presence of oil is discussed in U.S. Pat. No. 5,084,617, which uses a monochromatic light laser as the source of ultraviolet radiation. The light is brought to the surface by an optical cable. After the fluorescent image is generated, it is transmitted to a photometer sensor which evaluates the intensity of the light produced. The disadvantage of this device is low sensitivity and measurement of very small areas.

SUMMARY OF THE INVENTION

The above drawbacks are overcome by the method and apparatus for controlling the oil contamination of solid surfaces according to the invention, which is based on the use of fluorescence activated by light in the ultraviolet region and observable in the visible region of the light spectrum. Either the fluorescence of unsaturated conjugated compounds, especially aromatic hydrocarbons and unsaturated fatty acids contained in contaminants (eg cutting emulsions, mineral, vegetable oils, greases and animal fats) is used to accurately measure the amount and control the grease distribution. a fluorescent agent fully soluble in said mixture is added to the pollutant mixture.

The control is performed by observation through an optoelectronic device that allows fluorescence control and suppression of visible light from the environment. The amount of grease and its spatial distribution can be measured using a digital CCD camera (1), wherein the camera shutter is synchronized with the ultraviolet radiation source. It uses a narrowband filter (3) on the camera lens to filter out the reflected ultraviolet radiation. As a source of ultraviolet radiation, a lamp (4) having a short maximum of 0.01 second impulse discharge having a power of from 1 to 100 000 W is used, with a filter (5) to remove radiation in the visible range of the spectrum. The lamp is electronically synchronized with the camera shutter (6) and the flash fires with the evaluation program. The influence of ambient light is suppressed by overlaying the digital images of the CCD camera, a non-illuminated surface with ultraviolet radiation and subsequent illumination with ultraviolet radiation. The images (7) are processed and evaluated. For better identification of the contamination point, the image with the dirt (8), which is highlighted in color, is then applied to the original surface image without ultraviolet radiation. The entire process will run automatically within a short time. The magnification using the lenses (2) on the CCD camera is selected depending on the area to be controlled and the desired output purity.

The advantage of the method and apparatus according to the invention is the rapid, direct control of the oil contamination of solid surfaces with oil or grease directly at the contamination site in an operation without expensive equipment.

It allows you to search for places with oil contamination and measure the amount of oil on the surface.

In the case of the metal control after degreasing, it allows the elimination of defective production and repetition of the degreasing process, while at the same time the quality of degreasing in individual technologies is controlled. Another advantage is the possibility of controlling the operation of the degreasing device for optimum use of degreasing solutions. The present invention can be applied advantageously as an automatic production monitoring with an appropriate error indication in the degreasing process, wherein the sensitivity of the measurement of the amount of grease, according to the needs of the following operations, is adjustable by means of a light curtain.

The advantage of the device according to the invention is the long-term safe operation without ozone formation, since the energy supplied in the form of an impulse produces it in a minimal amount. Further, the advantage of the method is the ability to process fluorescence measurements without obscuring the control surface or its surroundings. Also the ability to archive and document long-term measurements.

The device according to the invention can be inspected continuously.

The sensitivity of the measurement for each type of contamination is dependent on the concentration of fluorescent substances relative to the total amount of impurity, their layer thickness on the surface, the power of the ultraviolet light used, the sensitivity of the CCD camera and the magnification on the camera lens.

Preferably, filtered wavelength ultraviolet light with a maximum between 320 and 390 nm from conventional light sources can be used and captured by an appropriate photocell.

Further explanation of the subject matter of the invention is apparent from the examples of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Example 1

The device of this patent has been used to inspect large, complex shaft and gear parts after degreasing and before ion nitriding. Inspection was performed by measuring up to 8 meters long and 1 meter wide and high components for marine gearboxes directly in service on nitrided components. The control device according to this patent operated with a detection limit of 2 mg of petroleum substances / m ² . By incorporating the control, the oil service life of the vacuum pumps of the ion nitriding device was increased.

Example 2

Small automotive aluminum parts that were precisely cast and subsequently machined. A cooling emulsion was used for machining. After machining, they were cleaned and degreased in water-vapor baths by ultrasound. Before application of the powder paints, they were checked gravimetrically according to STN 03 8215 and at the same time they were inspected by the device according to this patent. The results of the gravimetric measurements coincided with the results of the apparatus of this patent. Contaminated components identified by gravimetric measurements were also confirmed by additional fluorescent measurements indicating where the impurities are located. Images were taken to indicate different thicknesses of contamination on the aluminum surface with different colors.

Example 3

The device, according to this patent, was used to monitor oil contamination on the welded parts, where the welding points had to be clean, but the surroundings had to be re-oiled as the flying scales from welding were melted on the degreased metal. With patented equipment, it was possible to control oily and non-oily surfaces and thereby improve the quality of the metal surface after welding.

Example 4

The device according to this patent was used to check the quality of the cleaning prior to galvanizing the components in the suspension line. Inspection was performed after coarse purification in trichlorethylene, before electrochemical purification the quality was detected at 100X magnification. The controlled surface was checked with a resolution of 2 x 2 μιτι, using a conventional photographic flash sync with the CCD camera shutter using the appropriate software equipment as the radiation source. Measurements were performed while working in the galvanic workshop without adjusting the room lighting.

Example 5

The apparatus of this patent was used to check the cleanliness of glass surfaces prior to etching with hydrofluoric acid. Selective etching of the glass allows paraffin to coat the glass surface before etching. Locations on the glass surface to which the paraffin has been applied will remain etched. Therefore, it is advisable to check the application on the glass surface. When inspected on the surface with this patent, it is necessary to mix the paraffin with the fluorescent prior to deposition, in liquid form at elevated temperature, since the paraffin does not contain unsaturated functional groups with free electron pairs, which are a prerequisite for producing fluorescent light.

Example 6

The device according to this patent was used to check soil samples. The contaminated soil with oil petroleum was checked for oil content and distribution on the surface. The measuring device was used directly at the contamination site and controlled the area. Oil containing sites were marked for decontamination.

Claims (6)

PATENT CLAIMS 1. A method and apparatus for controlling the oil contamination of solid surfaces, characterized in that the fluorescence of mineral oil and / or grease components of animal and vegetable character is used to control and measure the amount and distribution of greases and / or oil on a rigid surface; present on a rigid surface. A method and apparatus for controlling the oil contamination of solid surfaces according to claim 1, characterized in that ultraviolet light from a source of 1 to 100,000 W and a wavelength of up to 410 nm is used to produce a fluorescent image. per measurement area delivered in the form of a pulse with a maximum exposure time of 0.01 second of exposure, synchronized with the shutter of the digital CCD camera. Method and apparatus for controlling the oil contamination of solid surfaces according to claims 1 and 2, characterized in that the fluorescence measurement is performed in the presence of visible light illumination of the inspected surface, which can reach a maximum of 100,000 lux during the measurement. Method and apparatus for controlling the oil contamination of solid surfaces according to claims 1 to 3, characterized in that the influence of visible light on the measurement is suppressed by a comparative method, by comparing the image of the inspected surface under ambient light without ultraviolet radiation, of the same surface with additional exposure to ultraviolet light in a digitized form. Method and apparatus for controlling the oil contamination of solid surfaces according to claims 1 to 4, characterized in that the resulting image of the object with highlighted oil and / or greasy points can be displayed on the computer monitor, stored as information in the computer memory, or print from printer. A method and apparatus for controlling the oil contamination of solid surfaces according to claims 1 to 5, characterized in that, if a higher or lower detection value is required, it uses an increasing or decreasing array of optical lenses on the scanning digital CCD camera of the device.