The definition of cleanliness limits is relevant in order to ensure and guarantee the quality and functionality of the systems. An effective method for checking the technical cleanliness of such systems is air extraction, which is an alternative to classic wet extraction among the methods for residual dirt analysis. The particles are blown off and collected on a special membrane.
Air extraction offers several advantages:
- Possibility of non-destructive and gentle testing: ideal for sensitive components such as displays, electronics and rubber hoses
- Suitable for testing air and gas-carrying parts
- Reuse of the tested components
Air extraction is divided into three methods: blowing off, flowing through and suctioning off.
- Blowing off is suitable for the outside areas or interior areas of components that are accessible to a compressed air jet and that should not come into contact with liquids during production and operation or that could be damaged by contact with liquids. Typical application examples are electronic circuit boards, individual parts in the intake tract that cannot be flowed through, and packaging materials such as KTL, blisters and cardboard boxes.
- Flowing through is used for the interior areas of flowable components that must not come into contact with liquids during production and use or that can be damaged by contact with liquids. This method is suitable for components such as hoses, housings, filters, manifolds and bellows in the intake tract.
- Suctioning off is an extension of the air extraction described in standards. The qualification of the test up to the light-optical analysis is carried out in accordance with the standards VDA 19.1 / ISO 16232:2018, which leads to reproducible results. Suction extraction is particularly characterized by its independence from closed test rooms and the possibility of mobile use. The extraction of particles takes place by sucking dry particles from component surfaces or specific control areas.
The following video shows an application of the Air Jet method to determine technical cleanliness:
The areas of application for air extraction are diverse and include:
- Pressure and oil area
- Fuel systems
- Brake systems
- Cooling and air conditioning systems
- Intake and exhaust tract
- Manual, automatic and axle transmissions
- Electronics
- Steering systems
Air extraction is an effective and gentle method for residual dirt analysis, which ensures both a high level of technical cleanliness and enables the components to continue to be used.
In order to ensure the technical cleanliness requirements according to VDA 19, flushing extraction can be carried out on pipes, for example. In this extraction, a test liquid is flowed through the inside of an object using a flushing stand in order to loosen and remove the particles on the wetted inner surface. The particles to be measured are collected on a membrane and evaluated.
The process is used to simulate a flow process in a practical way for the following components, among others:
- Pipes
- Filters
- Heat exchangers
- Injectors
- Pumps
- Valves
- Gears
These components, which are used in media-carrying systems, are part of technical systems, vehicles or machines. They are used to transport, filter, cool or control liquids, gases or heat. In many cases, these are sensitive to contamination and require regular maintenance or inspection to ensure proper function and high levels of cleanliness.
During the measurement, characteristic parameters such as volume flow, liquid quantity and flushing time are determined via the decline curve.
The most common method for particle extraction is spraying component surfaces with a liquid jet. Possible components are all functionally relevant parts and decorative components, such as housings or displays.
In this method for residual dirt analysis, test liquid is applied locally to the component using a free jet. This allows samples to be taken in the laboratory to test technical cleanliness. The method is suitable for cleaning external geometries and accessible internal geometries.
The spray method allows different parameters to be used - depending on the geometry of the respective control surfaces - in order to achieve the most effective particle detachment possible. The particles to be measured are collected on a membrane and evaluated.
The characteristic parameters such as volume flow, nozzle geometry, spray distance and liquid quantity are determined via the decline curve.
Spray extraction enables targeted and effective residual dirt analysis according to ISO 16232:2018 and VDA 19.1 by using parameters adapted to the geometry to efficiently remove dirt particles.
Ultrasonic extraction is a common, easy-to-use method in the laboratory for achieving technical cleanliness and is suitable for both internal and external contours.
This type of extraction is an effective method for analyzing residual dirt on component surfaces, in which the object to be tested is treated with mechanical vibrations in a frequency range of 35kHz / 130 kHz. The component is placed in an immersion bath in which cavitation bubbles are created. The cleaning power of this method is based on the high pressure peaks that arise when these bubbles implode and effectively release dirt particles from the surface. The cleaning liquid with the dissolved particles is then filtered, with the particles being deposited on the analysis filter. These extracted particles are then evaluated using a suitable method.
Ultrasonic extraction is particularly suitable for very small parts that can be treated with ultrasound in the immersion bath at the same time:
- Lamellar package for a stator
- Metal contacts
- Metal sleeves
Important parameters such as power, duration and frequency are precisely adjusted by the decline curve in order to achieve an optimal cleaning effect.
Ultrasonic extraction is an easy-to-use and effective method for determining the technical cleanliness of component surfaces, which enables both internal and external contours to be determined using mechanical vibrations and cavitation bubbles and is particularly suitable for the residual dirt analysis of small parts.
The suction extracting process is a dry method for determining the technical cleanliness of components and is used particularly for large, oversized or overweight components. The particle suction separator can be used to effectively measure the particle load on component surfaces without the need for wet extraction. This method is suitable for empty containers such as trays and for battery and high-voltage systems. Another possible application of the particle suction separator is its use in active monitoring in production or test environments in accordance with VDA 19.2.
Advantages of the particle suction separator:
- No blank value determination of the device necessary, just a new mesh fabric filter (e.g. 20µm Jomesa)
- Direct separation of particles (see Figure 1)
- Partial surfaces of components can be precisely tested separately
- Large components can be specifically vacuumed
- No wet extraction
- On-site use (in-line tests)
- No maintenance of the particle suction separator necessary
- Little training effort
- Robot-assisted automation possible
- Reuse of components after extraction
- Cost-reducing, economical, time-saving, reliable
- Reproducible results
- Logistical effort is very low
- ESD safe material
- Can also be implemented in a variable shape according to customer requirements (small filter diameter)
The following application video shows how a suction extraction is carried out to determine technical cleanliness:
Suction extraction for residual dirt analysis saves time and money and offers a reliable and economical solution for testing technical cleanliness thanks to its easy handling and the dry extraction principle.
Operating principle of the particle suction separator
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Copyright by A Solution (represented by Dipl.-Ing. Alexej Romanenko)
Partikelsaugabscheider / Particle Suction Separator
Utility Model Protection by the German Patent and Trade Mark Office no. 20 2023 002 150
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