Servizio Comunitario di Informazione in materia di Ricerca e Sviluppo - CORDIS

Final Report Summary - DOCA (Detection of Oil in Compressed Air (DOCA))

Executive Summary:
The project aims to solve a major problem plaguing the industry regarding the detection of oil contaminants in high purity compressed air. It aims to develop an online sensor that will detect oil contaminants in all its forms (liquid, aerosol and vapor) with an extremely high sensitivity in accordance with ISO-8573 Class 1 standards. The lack of any reliable, highly sensitive, online sensor system has forced critical industries to rely on manual sampling and laboratory analysis which is labour intensive, inefficient, and cannot guarantee the conformance of the compressed air system to mandatory or industry adopted regulatory norms. The sensor system will benefit a large category of industries that require high purity compressed air including, hospitals, pharmaceutical, automotive, chemical, textiles, electronics, clean rooms and other related industries. The ability to detect contaminants online, will significantly enhance the capabilities of these companies to guarantee the quality of their products and eliminate a number of risks and civil liabilities that are associated with non-conformance. To achieve the project results, a consortium of 3 competent SMEs with an interest in the area of sensor development partnered with 3 leading research partners for the development of this project proposal. The major requirement for the sensor element is extremely high sensitivity, repeatability, robustness to interference, and stable calibration. It was decided after much deliberation that optical spectroscopy is the most promising technology for the development of such a sensor. We have dedicated 3 work packages (WP4, 5, and 6) for the development of three key components that are vital for the development of the sensor - namely development of the sampling system, development of the optical spectroscopy unit and development of electronics and software. The project has in little more than 2 years delivered a prototype sensor system that fulfills the requirements for a Class 1 or better sensor, which can be traceable calibrated by a national metrology institute.

Project Context and Objectives:
The consortium behind DOCA wished to address a major market opportunity in the supply of advanced prealarm systems and sensor elements which will detect oil contaminants in compressed air systems in real time. More specifically DOCA’s objective is to develop and commercialize a novel IN-SITU sensor platform which, in real time, has the ability to detect and measure oil contamination in aerosol, vapour and liquid form in compressed air systems in accordance with class 1 requirements according to the ISO 8573 standard. This allows for radically improved protection of human health and material values against contamination. The developed technology has the potential to complement and/or substitute expensive and slow laboratory testing procedures and circumvent the extremely high risks associated with the chances of a detection failure in time.

Project objectives

The overall project goal lies in the development of a cost effective technological product that can efficiently fulfil the technological requirements of a wide spectrum of industries that depend on compressed air. While the concept behind the project is simply developing the technological tools for a simple and cost effective implementation of a global standard widely used in the compressed air industry: the ISO-8573, the project will have far reaching implications for the industry. Oil contaminants in compressed air, even in miniscule quantities can be disastrous for a vast variety of industries such as food and beverage processing, pharmaceutical manufacturing and packaging, chemical and petrochemical processing, semiconductor and electronics manufacturing, the medical sector, automotive paint spraying, textile manufacturing, amongst several others.


Compressed air with requirements of high purity is a frequently-used source of power in industrial environments – and a central element in a large variety of industries. It is used in pneumatics for driving different types of valves and actuators in the automotive and process industries. It is used as a gas duster for cleaning electronic components in the electronics and semiconductor industry. Airjet weaving and airjet spinning use compressed air for pick insertion and yarn consolidation in the textile industry. Other applications of compressed air include automotive industry spray paint booths, tobacco industry air washers, hospital surgery and nursery rooms, photographic film manufacturing plants, and aircraft industry clean rooms. In addition to high purity compressed air requirements in the above mentioned industries, clean compressed air is extremely vital for maintaining cleanliness and hygiene in the food and beverage industries, where contaminations can lead to grave consequences.

The wide-spread use of compressed air has resulted in increased contamination vulnerability – and industry, as a consequence, has been subject to strict regulation and standards. In this context, ISO-8573 is the most important international standard. Current standard methods for evaluating the oil content of compressed air take at least a couple of days to complete and are based on labor intensive sampling and laboratory analysis. Industries with critical oil contamination- free compressed air requirements often perform periodic air sampling and send it to laboratories for intensive GC-MS based testing. The cost for a single test is known to be around 3000 Euros. While this exhibits a large financial expense for organizations with huge compressed air systems and many sampling points, sampling and testing approach is not feasible to guarantee oil-free air as other than the compressor, oil contamination can occur at several points throughout the system. Also, contamination can be induced by hydrocarbon particles in ambient air, even when the compressed air system does not have any prior contamination. Hence periodic sampling and lab testing will not be able to effectively mitigate the risks associated with oil contamination.
There is thus an urgent and growing need for instantaneous monitoring, which enables proactive intervention. The developed technology will improve safety of production systems and significantly reduce costs for end-users, as quality presently is ensured through periodic lab tests and other costly preventive measures. The development of an in-situ sensor measurement system will be able to integrate real time oil quality monitoring with the SCADA and Distributed Control Systems of the plants. This would help the industry move in the direction of minimal human intervention and increased automation, which also reduces the chances of a human error.

Leading users and OEMs in industry have estimated that an effective sensor solution would be several times more cost-efficient than the preventive measures and manual sampling and lab testing that today represents the state-of-the-art. These characteristics give a successfully developed DOCA technology competitive advantage and broad applicability in a primary market, which in terms of size exceeds 3 Billion Euros.

The ‘Detection of oil in compressed air’ unit (DOCA) is a sensor that provide continuous online (in-situ) measurements of oil contamination in compressed air system, at segments where online alert protection for oil trace concentrations is necessary such as in medical, pharmaceutical, industrial or laboratory environment. The DOCA sensor provide a unique sensitivity that allow detection of <1 ppb contamination levels of all lubrication and combinations of oils.

The DOCA system can be installed in one or multiple places into compressed air system, depending on specific requirements. However, it is appropriate that a DOCA system is placed at the inlet to the compressed air process and cleaning chain. If the DOCA sensor is set to regulate a safety valve, then it is advantageous to install the DOCA sensor ahead of the safety valve such that the DOCA sensor can still be used during maintenance of the contaminated system.

The DOCA system consists of a sample collector piece that is installed into the compressed air system, a sensor module and a driver module. In future generations of the sensor the latter two items will be merged into a single casing. The sensor can be operated above the required flow of 1.7 l/min and has been tested experimentally with 2l/min flow and concentration measurements below 1 ppb were demonstrated.

Project Results:
The main S & T results/foregrounds are a sampling system; an optical spectroscopy unit (sensor head); algorithms and electronics as well as a completed prototype unit.

Sampling system

The ‘interface’ between the compressed air system and the online sensor is critical as it warrants that representative samples of the compressed air are taken. Air samples are taken using the so-called isokinetic sampling method. A sampling device was designed and manufactured and finally tested using the oil sensor system developed by the project partners.

The online sensor will be connected to the sampling probe. More details on isokinetic sampling can be found in the ISO 8573-2 standard. The general dimensions of the construction follow the recommendations for the dimensions given in the standard. In addition, according to additional internal product specifications the system should be able to work up to a pressure of 16 bar and be able to stand pressure pulses up to 32 bar (<1 second). Thus a relatively robust and therefore heavy design that can withstand these high pressures was made. The system consists of bare stainless steel elements. In case the sampling system should become contaminated with oil and possibly other substances a cleaning procedure was established.

The connection of the sensor to compressed air system is achieved by using a patented quick lock system. The experimental sampling system has been designed and realized according to ISO-8753 and the products specifications. Gas enters the system and part of the gas enters the probe which has been placed at the center of system. Due to the particular choice of tube lengths and diameters, the speed of gas in the system is the same as speed of gas in the probe. The setup has been tested. A linear dependency between the signal and the oil component was observed, confirming the proper functioning of the sampling system for this compound.

The Sensor Head

The DOCA sensor was tested for the following parameters: sensitivity (ppb level), accuracy and total measurement uncertainty, long term stability, response time, reproducibility, bias/background signals.

Certified oil samples used for the measurements were prepared by one of the partners. The linearity of the sensor was verified for hexane (C6H14) and decane (C10H22) with uncertainties of less than 3%. This demonstrates the potential of the DOCA sensor for measuring all five ISO classes of oil contamination in compressed air.

The reproducibility and the response time of the sensor the sensor was tested at a certain flow and low oil concentration and the reproducibility was shown to be within 1% from peak to peak and with a class 1 sensitivity (STD < 8 ppb). For higher concentrations (10 ppm) the reproducibility of the DOCA system is within 0.2% peak to peak. The response time of the sensor is fairly quick and it stabilizes within 30 seconds.

The long-term stability of the sensor was demonstrated by comparison with measurements conducted using mass loss over time with a sensitive balance. Knowledge of the mixing ratios for the various dilution steps leads to knowledge of the concentration. The data were recorded over 16500 sec (4.58 hours). There is good agreement and it could even be demonstrated that there were oil condensation in the diluting system, which was slowly evaporating resulting in slightly higher concentration as measured by the DOCA cell. Even though the uncertainty of the preparation (mass loss) is relatively high the output from system as measured by the DOCA cell has an uncertainty which is one order of magnitude lower.

A compressed air system was simulated in order to test the sensor for sudden air bursts. A uniform air flow is created from the compressed air system without influencing the air flow in the system. By using mass flow controllers and safety valves the cell could be protected from sudden pressure bursts (1-8 bars) in the compressed air system. It was demonstrated that the system is stable when coupled directly to real compressed air system in a factory facility.

In summary the data measured shows that the DOCA sensor fulfills many of its requirements, namely (most important) the sensitivity, reproducibility, flow and response time.

Sensor characteristics:
Sensitivity: 0.28 ppb (class 1: 8 ppb)
Reproducibility: Within 1%
Time response: Less than 15 seconds
Flow response: 2L/min flow without reducing the sensitivity.
Any liquid oil or oil aerosol needs to be heated before entering the sensor. This procedure has been used in the above data.

Algorithms and electronics

The electronics unit is intentionally made robust and highly modular to facilitate on-site demos, to allow experiments and to establish a firm basis for the decisions on what to integrate when maturing the setup into a product.

Through software the system control unit provides provide control and monitoring of the vital parts in the DOCA sensor. The unit is controlled and data collected via a laptop. The unit facilitate calibration of the sensor system and thus provide accurate measurement of oil concentrations.

The three units discussed above were integrated and a complete technical fully functional prototype sensor were put together. The prototype was constructed so that proper account of ease of operation and access to measured data were taken. 3D design drawings were made and functional specifications provided. For future manufacturing, suppliers of components were identified.

Potential Impact:
The identified scientific outcome of the DOCA project is summarised by the defined deliverables. Most deliverables will result in a report, publication or a demonstration, which will be published.

A key scientific outcome of the project is the DOCA technology patent being filed first in Denmark and subsequently to be followed by an international PCT patent filing early 2016. The novelty searches made within existing patent databases supports that the developed technology is unique and innovative. The sensor system technology is a novel and valuable instrument to implement critical and continuous monitoring of contamination of compressed air. It fulfill the requirements of a class 1 sensor and it will allow for considerably cost reduction and quality and safety improvement in various industrial processes.

The consortium will not communicate fully openly about the technology until the patent application has been processed. This is also reflected in the exploitation strategy. Consideration are taken to potential markets, threats, technical as well as other barriers is of high importance, such as intellectual properties, when planning exploitation and dissemination output and actions.

Potential markets

The partners have discovered a number of sectors in addition to those listed above that can be exploited based upon the improved resolution of measurements possible with the new technology. The sectors include 1) hospitals, 2) high purity compressed air in industrial environments, 3) care homes and other care facilities, 4) fire service operatives, 5) commercial diving operations, 6) Industrial applications where breathing apparatus is required as a safety measure. This last sector include such tasks as paint spraying, confined space entry operations, chemical processing, oil and gas and underground services maintenance

Knowing competitors and demands from the market creates a huge advantage when planning the exploitation and dissemination.

The unique value proposition for the DOCA device:
• The sensor measuring accuracy which is according to ISO 8573 Class 1 or better
• Calibration according to national metrology standards
• The device can identify gases individually due to their individual unique spectra
• The source wavelength can be chosen so that the response due to foreign gases present in the compressed air can be minimised and quantified.
The partners are very observant of new potential competitive products reaching the market.

Analysis of suppliers as potential marketing partners
To maximise the speed of exploitation of the DOCA project, one possibility is to find one or two partners who already have access to relevant markets. This involved looking at their current customer bases and product ranges to find the best fit to the project. Meetings were held with suppliers of existing gas detection equipment where discussions were held around the current market for the monitoring of oil is compressed air.

Exploitable Results
Three project results have been identified at the onset of the project. It could be that more will become apparent throughout the life of the project: sampling device, spectroscopic unit and electronics. There are potential additional discoveries that did not go into the final unit, which can be exploited.

All exploitable results have a potential for industrial applications as well as a future potential for the SME participants as providers of related service, such as installation, repair, special solutions based on the same device and optical solution. All results will be exploited by the SME participant by way of distribution agreements.

The development of the sensors and associated optical and electronic devices will allow the SME participants to expand their existing market areas and to venture into new markets, which will be identified and discussed towards the end of the project.

Dissemination Strategy
Dissemination of the knowledge gained is an important element of the DOCA project, especially in the preparation of commercial take-up of the scientific results. The DOCA project learning and results will be made widely available to the European scientific community via a variety of mechanisms: meetings, road shows, seminars, trade shows. The partners will contribute to written articles, mainly targeted at the scientific community. Journal publications have been postponed till patent submission has been completed. It is estimated that four refereed publications can result from the project.

The partners will contribute to written papers to be published in conference proceedings which will be delivered orally. Conference contributions have been postponed till the patent process has been completed. It is estimated that two conference talks can result from the project.

Members of the consortium will attend exhibitions and trade fairs.

Exploitation Strategy
Without a final product, and before the patent has been filed and processed – both in Denmark and internationally – it has been difficult to market the idea of DOCA although several activities have been undertaken to deliver some activity in this area. We expect that the sensor technology is novel and unique, and should therefore be protected. Communicating openly in public is therefore a major risk for the consortium, and the exploitation strategy and approach reflects this with an emphasis on confidential discussions with potential distributors, OEMs and other partners. It is important that the knowledge developed within DOCA continues to exist beyond the life of the project. Furthermore, it should be made accessible and usable to other parties, in research and industry.

Marketing Campaigns
The SMEs carry out a series of marketing campaigns throughout the year and DOCA will be included in these campaigns when appropriate. These are carried out by a combination of mailings, email shots, advertising and press releases. Mailings and email shots are sent to our existing database, for example over 30,000 industrial and commercial Castle contacts. New databases of contacts will be bought in as necessary. Adverts and press releases will be sent to the journals and publications in our existing database and to those identified in 5.1. All resulting inquiries are followed up with visits and demonstrations as necessary. Both PAJ Group and Castle Group also has a network of distributors worldwide who will be involved in the exploitation of the results of the DOCA project where appropriate. CMS already has access to the medical market in many European countries and a number of countries around the rest of the world as a manufacturer of medical gas supply systems with over 20 years of experience in controlling compressed air plants. When addressing the medical market there are two options. The first would be to address companies that equip hospitals with medical gas installations. There are a few major companies that also sell other equipment to the hospital, like operation theatre equipment, anesthetics machines etc. But there are also several smaller companies that are more confined to medical gas installations. All of these companies do not only install compressed air plants, they typically remain as a contractor for maintenance work. A second option would be to address medical facilities as the end user directly. Here it has to be taken into account, that hospitals will have their “appointed medical gas installation company” as mentioned above. They will probably consult when making alterations to the compressed air supply.

List of Websites:

Contact: Jan C. Petersen, Danish Fundamental Metrology, Matematiktorvet 307, DK-2800 Kongens Lyngby
Phone: +45 27288446

Contact: Christian Berndt, CMS Medizinische Anlagen und Systeme GmbH, Kordelweg 1, D-54470 Bernkastel-Kues
Phone: +49 6531 9739-0

Contact: Simon Bull, Castle Group Ltd, Scarborough, YO11 3UZ, UK
Phone: +44 1723 584250

Contact: Søren Laungaard, PAJ GROUP
Mobile +45 30 11 08 55

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