The 11th International Fluid Power Conference, 11. IFK, March 19-21, 2018, Aachen, Germany The 11th International Fluid Power Conference, 11. IFK, March 19-21, 2018, Aachen, Germany

Bond of 3+ Decades of an AvH Awardee at RWTH Researching Water Hydraulics

Shimpei Miyakawa*

Japan Fluid Power Association, 3-5-8, Shiba-kouen, Minato-ku, Tokyo 105-0011 Japan* E-Mail: [email protected]

Figure 2: First meeting with Prof. Backé in March 1983

During the last 34 years, Dr. Shimpei Miyakawa paid several visits to the IHP and IFAS at RWTH Aachen Prior to his return to Japan in January 1986, Prof. Backé asked about a research subject to be undertaken in University. Throughout his stays in Aachen and his work in Japan, he gathered profound knowledge of the Japan. This question shaped his future. Based on conversations with Prof. Backé, this article describes his applications of water hydraulics. In many talks with Prof. Backé and his successor, Prof. Murrenhoff, Dr. development process of water hydraulics through mentorship and guidance and through the bond with 3 Miyakawa discussed the development of water hydraulics and its possible application, especially in the food Professors in 33 years in chronological order. His family enjoyed company of Prof. Murrenhoff, then Chief market. The text gives an overview over his stays in Aachen and how these influenced his personal development Engineer at IHP. Since the homes were close to Aachen-Laurensberg at that time, the families engaged in regular of water hydraulics systems. visits.

Keywords: Water hydraulics, history, food market, IFAS, Alexander von Humboldt Target audience: Anniversary guests

1 Experience as AvH-Visiting-Fellow led to the development of a new technology Figure 3: Bitburger

“Bitburger” was the first German beer Dr. Miyakawa tasted in a local Kneipe. It was a superb experience leading to regular stays at the Postwagen near Aachen’s town hall.

2 Patent application of the new technology and verification of principle and Functions After returning to Japan in the end of January 1986, he visited Germany several times in the following years to continue the research.

Prof. Backé used the opportunities to ask Dr. Miyakawa about his research subjects to be undertaken in Japan. He was working for Ebara Corporation at that time. The company had already withdrawn from the existing oil hydraulic business, which was his area of expertise. He was part of the Ebara’s research institute but had not Figure 1: Alexander von Humboldt-Stftung, Dr. Shimpei Miyakawa, determined on the research subject yet. On April 1, 1987, he was transferred from research to development and November 1984 to January 1986, May to September, 2004 started to explore the research subject. After screening potential subjects, he decided to join the development of water hydraulics to contribute to the company’s water-related business by using his experience in oil hydraulics. From July 1984 to January 1986, Dr. Miyakawa stayed as a visiting fellow at IHP (Institut für hydraulische und When the decision was made, he had 17-year experience in oil hydraulics dating back to April 1970. Being pneumatische Antriebe und Steuerungen, established under the direction of Prof. Backé in 1968), RWTH general knowledge that “water and oil never mix” and oil hydraulics having evolved from the fact that it is Aachen University. Preparation for this stay started with a preliminary meeting with Prof. Backé in March 1983. difficult to drive machines by using water as a working fluid, he recognized that it would be difficult to return to He took a German language training course in Bremen from July to October 1984. In November 1984, he started using water as a working fluid. The application of water hydraulics to a machine dates back to the patented a research project at IHP. Because of his missing linguistic skills, he attended a German language class held at hydraulic press invented by the English inventor, J. Bramah in 1795. Even though this was taught in European 18:00 p.m. at the Germanistisches Institut, RWTH Aachen University, taking steps in his linguistic headway. As Universities, it was not public knowledge in Japan at that time and further studies brought him deeper into the presented to Prof. Backé in advance during visits in Germany, his research subject was on oil hydraulics, which subject. was a continuation of the research conducted in Japan. In 1987, applications for water hydraulic servo valve patents were filed. Once again, Dr. Miyakawa learnt a lot with regard to preparatory patent searches in this field. A common practice should always start with searching similar existing patents and papers to be conducted by the company’s intellectual property or patent section. He filed a patent application for a water hydraulic servo valve having in mind that water hydraulic technologies should be smart and intelligent. Since oil hydraulics provides high power density and the key components in AL

523 The 11th International Fluid Power Conference, 11. IFK, March 19-21, 2018, Aachen, Germany The 11th International Fluid Power Conference, 11. IFK, March 19-21, 2018, Aachen, Germany developing fluid power technologies are pumps, developing a pump seemed to be the first step. However, setting cavitation, and 3) corrosion as well as the application of plastic materials as countermeasures for wear are up “intelligent water hydraulics” as a target technology; the first step was a “nozzle flapper control valve included in the published proceedings containing the lecture. Dr. Miyakawa realized that solutions for those incorporating electronic technologies” allowing connection with IT equipment. Not being aware yet of the three points should be keys for the development of water hydraulics. On this occasion, he found the link between challenging characters of a pump using water as its working fluid the chance for validation of the originality and Prof. Backé and water hydraulics. In later years, this water hydraulic pump was commercialized and also novelty of this technology was entirely dependent on the grant of a patent, see /1/. introduced to Japan.

In March 1989, at the first JFPS (Japan Fluid Power System Society) International Symposium held at the Tokyo Institute of Technology, Prof. Burrows of the University of Bath, who participated in the symposium with Prof. Backé, told him that swash plate water hydraulic pumps have already been put into practical use by a company FE in England. In later years, required for the international standardization of ADS described hereinafter, 1), 2), 3) and the application of plastic materials as described above became basic items to be studied to explain differences from oil hydraulics when a working fluid is changed from mineral oil to freshwater. These items turned out to be the greatest gifts from Prof. Backé.

In 1990, he commenced the study of water hydraulics available in Europe. At the time, proprietary water hydraulic technology was the above mentioned water hydraulic servo valve. No further knowledge regarding other water hydraulics was available. Dr. Miyakawa contacted Prof. Backé at IHP, RWTH Aachen University, Figure 4: US patent for a water hydraulic servo valve /1/ for some advice on German water hydraulic technologies. He introduced him to companies involved in water In the in-house research he started research by verifying functions of the valve technology. In the sliding hydraulics. Germany has a long history of high water-based fluids (HWBFs, HFA). The region located in the movement of elements in low viscosity fluid housed in a valve body, the effect of water film cannot be expected. Ruhr coalfield (Ruhrgebiet) had many companies offering water hydraulic equipment for safety purposes, If the structure and principle of the valve could be successfully verified, the development of the technology including explosion protection in the mines. HWBF or HFA is a special fluid that contains approximately 98 would be publicly funded by the Research Development Corporation of Japan. The concept of Ebara percent water with additives (for lubrication, corrosion prevention, etc.). In a broad sense, HWBF technologies Corporation was “if the technology is good enough, then public funding should be granted.” In 1989, the are included in water hydraulics being part of it. principles of the patent were verified, and a fund of 150 million yen (which was paid back in equal instalments with free of interest for five years after the development period of three years) was granted. Dr. Miyakawa has strong believe that the industry would be following a path toward the use of freshwater as a working fluid to drive machines, which should be the best choice from the viewpoints of both environment and resources. So he decided to develop washable precision machinery driven by water hydraulics. He was encouraged by the selfish pride as an employee of a leading company in water business already estimating that it would take 20 years to commercialize the technology. On the other hand, he was told by experts that it would usually take 25 to 30 years although this estimation was not made on sufficient grounds. By 1993, all patents including those applied in Japan were registered. Figure 4 shows the basic patent /1/.

Dr. Miyakawa still remembers the words received from the head of the Ebara Research (currently, a professor emeritus at the Tokyo Institute of Technology). “Usually, a huge amount of time is required for preparatory search to prove the novelty and originality of a world first invention. You have a time advantage of the invention. Since your findings will be referenced and cited by others, you don’t have to search for others’ Figure 5: HE's Unit findings. That’s an advantage of challenging a new research subject.” The viscosity of water is extremely low. Therefore, no advantageous effects of a water film in gaps can be expected. A structure with hydrostatic bearings was selected to realize a non-contact sliding of the valve body based on the principle of making water discharged from the structure with hydrostatic bearings flow into the nozzle flapper mechanism to regulate the nozzle back pressure. Another important technical point was the use of tribological technologies and corrosion preventive materials.

3 Field study of German water hydraulics technologies triggered by Prof. Backé’s statement “Technology development in water hydraulics is difficult” and

development of the Japanese market

In September 1988, the First Bath International Fluid Power Workshop (hosted by Prof. Burrows) was held at the University of Bath. During this workshop, a lecture on a water hydraulic pump was given by J. A. Currie, the pioneer of water hydraulic pumps in England (2). Prof. Backé’s questions on 1) friction and tribology, 2) AL

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Figure 6: HY's Unit Figure 6) and a relief valve, were bought from WV and HA. The components of a water hydraulic system were gradually procured. Since these preparations were proceeded on referral from Prof. Backé, Dr. Miyakawa had

the pleasure of dealing with the CEOs of those companies directly when visiting. Because of the close contacts, as the study of practical water hydraulics proceeded, the water hydraulic project progressed significantly. It can be concluded that the starting point were German water hydraulic technologies. Looking back on it the

significance of Prof. Backé’s support and the advice he continually provided me laid the foundations for the progress. If he were still alive today, the thanks and gratitude belong to him.

Soon the engagement in the applied development of a water hydraulic system based on a water hydraulic servo valve started; however, it was difficult to find market opportunities. Starting from an engineering background in oil hydraulics, even after doing R&D in water hydraulics, his market research focused on heavy industries. He assumed that potential customers would demand water hydraulics as alternatives for oil hydraulics. Dr. Miyakawa was urged from the management of the parent company to “not only develop a technology but also sell it”. The industry he assumed to be the potential probably was not a good target. So he focused on niches that

put a priority on cleanliness such as food and semiconductor industries. Since the main business of Ebara Figure 7: DU Corporation was the water-related business, it was not difficult to steer the direction of the market research to industries subject to cleanliness. He began to realize the meaning of “Challenges in a new product development

are often brought by customers.” It was necessary to not just be a researcher but a salesperson as well. Since then, his interest in studying shifted from technical books to marketing books. After having identified these potential markets, it he found the existing water hydraulic unit being too large to be incorporated in a user’s

system. So he put priority in the examination of a swash plate axial piston water hydraulic pump manufactured by FE in UK. The development of a water hydraulic system was advanced by using this small swash plate water hydraulic pump (Figure 9: FE's water hydraulic pump and the other German and Swiss radial water hydraulic pumps purchased around the same time).

Figure 8: WV directional control valve

Dr. Miyakawa started with the field study of the manufacturers of water hydraulic pumps as fundamental water

hydraulic pressure sources. Thanks to the prominence of Prof. Backé’s IHP for its fluid power research, influential individuals at those manufacturers kindly supported the field study as well as graduates from RWTH Figure 9: FE's water hydraulic pump Aachen University. He used chances to visit German companies, including HE, DU, WV, HA and a Swiss In February 1993, Dr. Miyakawa visited the University of Edinburgh to see a water hydraulic robot using a FE’s company called HY, all of which would be playing big roles in later years. On July 2, 1991, a set of radial water water hydraulic equipment. To see an all-ceramic seawater pump (a high-pressure positive displacement pump) hydraulic pump units (Figure 5) was purchased from HE, Germany. This pump was used as a hydraulic pressure he also visited a research institute at the University of Hull. To his astonishment, all the parts, including piston source for controlling the novel servo valve. It was a large water hydraulic pump but was considered to be more and cylinder block, were made of ceramics. He was impressed by the water hydraulic pump of the palm size (6 advantageous than a conventional triplex plunger pump in terms of pulsatile. Then, the technician of the German cc/rev., 16 MPa), which was exactly what he had been looking for. He requested the development of a smaller company moved to a Swiss company, HY, from which two water hydraulic pump units (Figure 6) were purchased water hydraulic pump (3 cc/rev., 16 MPa) and started the development of different water hydraulic machines, on October, 1992. On March 12, 1993, DU was requested to develop a radial water hydraulic motor for an including a nuclear reactor core cooling device model and a civil engineering machinery as countermeasures actuator (Figure 7). Control valves, such as a directional control valve ( against seismic liquefaction in 1994 and a food processing machinery around 1998. Specifically, vane motors with equivalent of electric motor output of 100/200 W (Figure 10) were developed for cutters in meat processing

machinery. All the applications were proposed for markets subject to product or machine contamination by oil. In 1997, a partner company of Ebara Corporation concluded a contract for the import and sales of FE’s water hydraulic equipment, which allowed to have priority use of swash plate water hydraulic pumps in Japan.

Through progress in technology development and the procurement of components, a new market for water hydraulics in Japan came into sight. Practical accomplishments were also seen.

AL

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4 Water-hydraulics-related Activities in Germany and Development of Japanese Market

In 2002, Prof. Backé (Photo in Figure 11) gathered parties involved in water hydraulics in Germany to hold a roundtable meeting, the details of which were published in “O+P” /9/. Although his article introducing Dr. Miyakawa’s activities did not fully reflect his scope of work, his mention of the name in public was a honour. Realizing that he was interested in water hydraulics, Dr. Miyakawa read the article with the help of a German dictionary. In later years, he became acquainted with people listed in the journal. At that time, in Germany, Figure 10: Water hydraulic vane motor for meat processing VDMA (Verband Deutscher Maschinen- und Anlagenbau, Mechanical Engineering Industry Association) played a central role in organizing and operating the committee of water hydraulics. Three lecture meetings on water Dr. Miyakawa had access to papers on low viscosity fluid from Prof. Backé’s archive at IHP, RWTH Aachen hydraulics were held in 1998 /10/, 2000 /11/, and 2002 /12/. The proceedings of these meetings helped him University, and learned a lot on technical issues, in particular, cavitation erosion and countermeasures /3-7/. greatly in later years. Many researchers and parties involved asked him the reason for its regular visits since Working fluids used for water hydraulic systems in the papers were HWBFs; however, the effect of viscosity 1986 after returning from IHP. Whenever Prof. Backé introduced him to others, he described him as an (particularly on cavitation) and the need of corrosion prevention are common characteristics in the case of tap Alexander von Humboldt visiting fellow from Japan. Since not only Prof. Backé but his secretary and many water as a working fluid. Prof. Backé’s words, “Water hydraulics is difficult,” always stayed in his mind. He was researchers extended warm hospitality to him, he came along with them on the bases of German learnt. During eager to know the reason of this statement. To discuss the matter, he needed not only to gain knowledge on water his stays in Aachen, he waited for Prof. Backé at the entrance of the laboratory to greet him every morning and hydraulics but also to master German. Before visiting Prof. Backé for the third time, he had to sum up findings went out of the laboratory after he left. achieved in Germany immediately and ask for his advice. Therefore, after returning to Japan in January 1986, he prioritized to publish the findings in “O+P, Ölhydraulik und Pneumatik”. Thanks to great support from a joint Dr. Miyakawa was invited to Prof. Backé’s home for the first time during his stay in Aachen in 1985. At that researcher, he finally could publish the findings in the journal /8/. The article was on oil hydraulics. time, he lived in the mentioned suburb of Aachen. Memories of him are: “I got stage fright and was only able to nod in response to his talk in German, finding it difficult to mention a single word. He spoke German, not English, to me very slowly, which encouraged me to study German harder.” Then, Prof. Backè moved to the city center of Aachen. Considering his increasing age, Dr. Miyakawa began to visit him at home, not his laboratory at the university, to update the progress. His first question was always about progress in the application of water hydraulics to the food sector. He thinks back: “I did not have enough confidence to answer to his technical questions, but his questions were centred in introduction to personal things rather than on technological issues. His wife gave a compliment to me for my achievements in the field different from Prof. Backé’s. He seemed to have significantly changed his opinion on water hydraulics around this point of time. He was eager to listen to my updates on progress in R&D and the introduction of water hydraulic systems to new markets. It is still not certain whether my explanation on water hydraulics with poor German skills was fully understood by the professor. However, one year until the following visit was too short to be prepared for his questions that are getting more difficult to answer. I used twelve hours during the flight back to Japan to plan how to make explanation to him at its next visit in the following year.” Figure 11: Prof. Backé at Water Hydraulic Roundtable Meeting (2002)

Figure 13: Prof. Backé listening to my reports

In the Japanese market, specific water-hydraulics-applied products appeared around 1998. A meat processing machine (in 2002) and a semiconductor wafer sealing molding press (in 2002) took the advantages of the patent-

filed water hydraulic servo valve. Finally, Dr. Miyakawa succeeded in reaching markets that potentially required Figure 12: Prof. Backé’s comment in “O+P” introducing Dr. Miyakawa’s activities at the committee water hydraulics and received a good response from the markets. He showed photos of these products to Prof. with rather generalized understanding AL

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Backé, who seemed to appreciate the situation. In March 1998, Prof. Murrenhoff hosted the first International After returning to Japan, the development of water hydraulics and market investigation were continued at the Fluid Power Conference, IFK. Dr. Miyakawa often got some advice from him mainly in terms of technical corporation to which water-related patents and facilities were transferred. Dr. Miyakawa’s regular visits to Prof. aspects. We discussed tribology of water hydraulic pumps using HWBFs. He also showed disagreement on Backé and Prof. Murrenhoff also continued. development of water hydraulics using tap water; however, this argument, particularly on durability, became a useful information thereafter. When visiting in 2001, a discussion began on the combination of materials to use. 6 Prof. Backé no longer mentioned difficulty in development of water hydraulics and The technical information exchange with Prof. Murrenhoff provided an opportunity to ask about further specific Prof. Murrenhoff provided the fundamentals of water hydraulic pumps support for development of water hydraulics in Japan. In March 2003, a research group of the Japan Fluid Power Association (JFPA) visited RWTH Aachen University, and a meeting hosted by VDMA was held, in which Prof. In August 2009, to celebrate Prof. Backé’s 83rd birthday, Dr. Miyakawa and his wife visited him at home Murrenhoff and many engineers involved in water hydraulics in Germany gathered together. Here, the group together with Prof. Burrows from the University of Bath and his wife. After dinner, he spoke of his personal could learn that the perspective of technology development and intention of markets for water hydraulics in history, including his birth in Tanzania, Africa, on July 25, 1926, coming to Germany, and establishing IHP Germany differ from each other. At the same time, he could understand the background of Prof. Backé’s words, (currently IFAS) in January 1968. Two professors and I talked over “the future of fluid power technologies” “Development of Water hydraulics is difficult.” On the other hand, market development of water hydraulics in endlessly until late at night. Dr. Miyakawa was fascinated by the talk of two professors both of whom were the Japan, as stated above, was progressing relatively smoothly. Supported by Prof. Murrenhoff, the outcomes pioneers of oil hydraulics. The research achievement of Prof. Backé from 1955 to 2009 is published as a book including specific water-hydraulics-applied products, along with the survey results on the market size, were /16/. On that occasion, he asked his opinion saying, “Miyakawa is a pioneer of water hydraulics.” and Prof. published in “O+P” (13). It was in 2003, the next year when the roundtable meeting on water hydraulics in Backé was told that his work on the flow force acting on the valve described in his dissertation /17/, was of great Germany was held by Prof. Backé. help in designing a water hydraulic servo valve. He keep his dissertations with great care. Time passed so fast over the two professors’ talk on “the memories and future of oil hydraulics”. Dr. Miyakwa was more than In November 2003, the water hydraulics project team in Ebara Research Co., Ltd. was dissolved and Dr. impressed to share precious time with them. Two professors suggested to continue the talk with their successors, Miyakawa decided to leave the company at the end of March 2004 and told Prof. Backé about the decision. Prof. Backé asked him what would happen to the water hydraulics project. He explained to him that a corporation Prof. Murrenhoff and Prof. Plummer (in the UK); however, unfortunately, this part has not been realized yet. decided to buy related patents and testing facilities of Ebara Research and that the project would be continued at the corporation.

5 Second stay at RWTH Aachen University as AvH-Visiting-Fellow and continuous development of water hydraulics

Figure 15: Prof. Backé and his wife, Prof. Burrows and his wife, and me on Prof. Backé’s 83rd birthday (2011)

For the applications of water hydraulics, the efforts focused on the marketing of food processing machinery, which was discussed before. He said, “This direction turned out to be right,” to Prof. Backé; he smiled and said, “Good.” That was the moment my efforts began to bear fruit. Then, again in “O+P”, an article on the historical background of water-based working fluids and the technological differences and market size of systems using tap water as a working fluid was published /18/.

Figure 14: Prof. Murrenhoff Around 2010, the team set out the commercialization of food processing machines for a specific market, which was funded by an organization associated with the Ministry of Agriculture, Forestry and Fisheries of Japan From May to September 2004, he stayed in Aachen again, supported by the Alexander von Humboldt (Figure 16). In Japan, there has been increasing awareness that our water hydraulic system, Aqua Drive System Foundation. This support was won through the efforts of Prof. Murrenhoff, the successor of Prof. Backé who (ADS), is an effective driving method for machines subject to HACCP (Hazard Analysis and Critical Control was very glad to know that the RWTH Aachen University with the support of the Alexander von Humboldt Point) which will be applied to exported and imported products to support “safety and reassurance of food”. Foundation took Dr. Miyakawa into care again. In those five months, he could round up water hydraulic ADS allows cleaning of food processing machines and components immediately after operation; therefore, technologies developed since 1987. attention was drawn to its improved productivity and hygiene as well as ease of maintenance. Then, ADS He started with reporting mainly technical matters to Prof. Murrenhoff. The initial advice from him about the evolved into an integrated structure of a forming press for frozen meat and a meat slicer, which was publicly type of hydraulic pumps, pressure specification and the basic structure was always “consider from the academic announced. perspective.” Subsequently, he gave me guidance on water hydraulic pumps using HWBFs /14, 15/. The technical details were getting more and more complicated. Around that time, he began to update progress in the development of the water hydraulic business to both Prof. Backé and Prof. Murrenhoff. AL

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Figure 18: Prof. Backé presented a working-fluid-filled champagne bottle at Prof. Murrenhoff’s 60th birthday

In 2013, on the occasion of Prof. Murrenhoff’s 60th birthday party, Prof. Backé presented a working-fluid-filled Figure 16: ADS-based meat processing machines champagne bottle, which made the guests excited. Dr. Miyakawa felt that this witty expression of expectation By August 2010, the main content of Dr. Miyakawa’s reports to Prof. Murrenhoff was shifting to specific and affection to his successor could be because of Prof. Backé’s special nature. At this instant, something came applications of water hydraulics. Among them were two axis robots, a given pressure wave generators which can to his mind remembering the Great East Japan Earthquake, which occurred in September 2011. On the way to be effectively applied to test equipment, and survey robots inside reactor core of a nuclear power plant. They use home from work going down the stairs of a train station his cellphone rang in the pocket. He took the phone and servo control system with water hydraulic servo valves. He also reported about a seawater desalination unit, placed it to his ear. It said, “Prof.Backé am Apparat. Dr. Miyakawa?” he was surprised. which is a combination of a pump and motor with permeation membrane and can convert backpressure into He continued “Are you all right? How can I donate?” It was early evening, in the crowded station. I can never energy by using the motor. forget this.

On some other evening, Dr. Miyakawa had an opportunity to visit Prof. Backé at home. There, he updated the progress of introduction of water hydraulics to the market. He no longer repeated his previous statement, “Technology development in water hydraulics is difficult.” Therefore, Dr. Miyakawa felt, that he finally admitted the advantages of water hydraulics. It was the moment when concerns over technology development in water hydraulics turned into reassurance.

From 2010 to 2015, outcomes of commercialization and basic research of ADS were presented in international symposiums in Aachen (Germany), Tampere (Finland), Linköping (Sweden), Bath (UK), and Japan /19-24/.

During one of his regular visits in August 2014, Prof. Backé had his 85th birthday. His secretary told Dr. Miyakawa that it might not be easy for him to listen to his updates because of his gradually decreasing physical

strength. Therefore, he called him directly for an update. He answered clearly and was far from being frail. Dr. Figure 17: Always start with “Prosit!” Miyakawa was relieved to see him eating a huge cake baked by his wife. He talked smoothly and listened to the On August 13, 2012, on regular visit to Prof. Murrenhoff to report the progress, he told Dr. Miyakawa about his updates. Then, he inscribed on a gift copy of what he described as “his last publication” /25/. Seeing “Herrn Prof. plans, including his 60th birthday party in August 2013. There was going to be a big celebration gathering with Miyakawa”, I told him, “I am not Prof. but Dr.-Eng.” He answered, “You are Prof. because you are a pioneer of lecture presentations. Around this time, main advice was coming down to the fact that what is important is the water hydraulics,” and his wife took a picture of Prof. Backé presenting the inscribed copy to me at his home. shape of the piston of a pump. For water hydraulic pumps, the surface of a piston is made of resin; however, the I reported to him that we had finally achieved the introduction of water hydraulics to the market. Again, he generation of contact stress with a cylinder block is similar to that of oil hydraulic pumps. The wear track of a pointed out, “It must be the food market. water hydraulic piston was compared with that of a piston I brought from Japan. A person in charge of pumps was called to have a direct discussion on the matter. Prof. Murrenhoff was kind enough to ease discussion with the talk about his plan for his 60th birthday party in next year. AL

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Figure 21: Integration of water hydraulic servo valve, water hydraulic unit, and forming press

Dr. Miyakawa immediately showed a resin protective film forming press for chip-sized devices adopted in a semiconductor process, which was put into practical use in 2002. He seemed to be satisfied with the food and semiconductor fields as markets that potentially require water hydraulics and nodded, “Right.” He told him that the product machines functioned, but also said, “The optimization of hydraulic energy transfer has not been

achieved yet.” The performance and energy consumption of water hydraulic systems still need to be addressed. Figure 19: Prof. Backé inscribing on a gift copy of his publication (at home) Prof. Backé advised him the importance of the balance of hydraulic energy consumption in each component. It was the moment Dr. Miyakawa felt certain that the standardization of water hydraulics would be critical sooner or later.

7 International standardization of ADS unreported to Prof. Backé Dr. Miyakawa told Prof. Backé the purpose of a visit in 2016 as “the international standardization of ADS”. He conveyed him its intention of proceeding the market development and standardization of ADS in parallel. He was thinking of visiting him earlier than usual. However, without hearing the outline of “the international standardization” from me, Prof. Backé passed away one week before the planned regular August visit. When he received the news, strength was suddenly gone from his legs and his head dazed. In an e-mail to Prof. Murrenhoff, he mentioned nothing but “great sorrow.”

At the end of 2016, Dr. Miyakawa left KYB Corporation to start working for the Japan Fluid Power Association (JFPA). While engaged in industry-wide activities related to water hydraulics, he was assigned as the Chairman

of ADS Technical Committee. Then, aiming at the international standardization of ADS, he visited Figure 20: Prof. Backé presenting the inscribed standardization-related organizations in Europe and the U.S. At these organizations, he met researchers who At a visit in August 2015, he asked whether the water hydraulic market had expanded. Dr. Miyakawa answered studied under Prof. Backé. This provided him with psychological support. that we had entered into the practical application of water hydraulics to meat processing machinery; then, he said, “The meat market is larger in Germany than in Japan.” A machine having an integrated structure of a meat slicer and a frozen meat forming press was introduced to the market. Prof. Backé pointed out the next target market would be the semiconductor market. Our conversation always centered in market-related issues.

Figure 22: Title of proposal at ISO TC131 meeting in San Antonio on May 18

Although his wish to tell Prof. Backé in person was not fulfilled, he would like to express that ADS was originated during his stay at RWTH Aachen University, Germany and the development of ADS was carried out through mentorship under Prof. Backé, Prof. Murrenhoff and his successor, Prof. Schmitz, as well as support of German water hydraulic equipment manufacturers. AL

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The ISO TC131 meeting was held in San Antonio on May 18, 2017. To his regret, the presentation of “Proposal /7/ H-J. Dittmer, Condition Monitoring für HFA-Hydraulik mit ölhydraulischen Geräten, November 2008, for Standardization of ADS” was not made. At the meeting, German VDMA members actively expressed their RWTH Aachen, Dissertation. opinions. However, he hopes this work for standardization to be advanced as a Japan-Germany joint work. /8/ S. Miyakawa, Fujisawa, K. Dluzik, Aachen, Dynamisches Verhalten eines Hubwerks mit einem Thirty-four years have passed since he met Prof. Backé for the first time in 1983. With the support from many geshcllossenen Hydraulikkreislauf, O+P “Ölhydraulik und Pneumatik”, 31 (1987) Nr. 8. people, ADS (a new water hydraulic system) has been put into practical applications. Dr. Miyakawa gained /9/ W. Backé, Gesprächsrunde: Wasserhydraulik, O+P, “Ölhydraulik und Pneumatik”, 46, (2002) Nr. 8. knowledge enormously from the three outstanding professors as well as German companies involved in water hydraulics and through books on water hydraulics in the RWTH Aachen University’s library. Likewise, he /10/ Informationsveranstaltung “Wasserhydraulik”, des Fachvervandes Fluidtechnik.im VDMA am 23. Juni would like to thank users in Japan for their understanding for ADS as well as JFPA (Japan Fluid Power 1998, 9:45 Uhr in Frankfrt (Main) Association), JFPS (Japan Fluid Power System Society) and companies involved in ADS for their great support, /11/ Informationsveranstaltung “Wasserhydraulik”, des Fachvervandes Fluidtechnik.im VDMA am 18. and hopes ADS become widely used around the world through international standardization. He strongly wishes Oktober 2000, 9:30 Uhr in Frankfurt (Main). that ADS contributes to the growth of diverse industries. /12/ M. Inantysynova, TU Hamburg-Harburg, Arbeitsbereich Flugzeugsystemtechnik. Wasserhydraulik Herausforderung & Chance für die Hydrostatik im 21. Jahrhundert, Informationsveranstaltung Wasserhydraulik, VDMA, 10. 2002.

/13/ S. Miyakawa, Anwendungen von Wasserantriebs-systemen, O+P “Ölhydraulik und Pneumatik”, 47 (2003) Nr. 4.

/14/ S. Gels, Einsatz konturierter und beschichteter Kolben-Buchse-Paare in Axialkolbenmaschinen in Schrägscheibenbauweise, November 2011, RWTH Aachen, Dissertation.

/15/ C. Enekes, Ausgewählte Maßnahmen zur Effizienzsteigerung von Axialkolbenmaschinen, Juni 2012, RWTH Aachen, Dissertation.

/16/ Beiträge von Wolfgang Backé, Aus der Entwicklungsgeschichte der Fluidtechnik 1955-2009, Shaker Figure 23: Prof. H. Murrenhoff, Prof. K. Schmitz and Dr. Miyakawa in Oct. 2017 Verlag GmbH.

/17/ W. Backé, Über die dynamische Stabilität hydraulischer Steuerungen unter Berücksichtigung der Acknowledgements Strömungskräfte, 13 Februar 1962. Finally, deep appreciation goes to Prof. Murrenhoff for providing this special opportunity at the 11th IFK to talk /18/ S. Miyakawa, Aqua-Drive-System, O+P “Ölhydraulik und Pneumatik”, 11-12/2010. about 33 years of career with water hydraulic development. This is the precious gift in my life. I would also like to express my sincere thanks you to Jutta and people in the secretary office of IFAS for their hospitality /19/ F. Yoshida, S. Miyakawa, Characteristics of Proportional Control Valve Using Tap Water, Proceedings especially during my long-term stays. 7th International Fluid Power Conference, 22-24 March 2010, Aachen, Germany. /20/ F. Yoshida, S. Miyakawa, Dynamic Characteristics of Proportional Control Valve using Tap Water- References Experimental Examination, Proceedings of the 12th Scandinavian international on Fluid Power, vol. 2, 18-20 May 2011, Tampere, Finland. /1/ United States Patent, HYDRAULIC SERVO-VALVE, Patent Number 5, 186, 213, Date of Patent: Feb.16, 1993. /21/ F. Yoshida, S. Miyakawa, Effect of Parameters on Frequency Characteristics of Proportional Valve Using Tap Water, Proceedings of 8th JFPS international Symposium on Fluid Power in Okinawa, 25-28 /2/ J. A. Currie, The Development of Raw Water Hydraulics, University of Bath, England, 8th September October 2011, Okinawa, Japan. 1988, FIRST BATH INTERNATIONAL FLUID POWER WORKSHOP, Edited by C. R. Burrows and N. D. Vaughan, RESEACH STUDIES PRESS LTD. /22/ F. Yoshida, S. Miyakawa, Effect of Design Parameter on Response Characteristics of Water hydraulic proportional Control Valves, Proceedings of the 13th Scandinavian International Conference on Fluid /3/ J. Berger, Kavitationserosion und Maßnahmen zu ihrer Vermeidung in Hydraulik-Anlagen für HAF- Power, 3-5 June 2013, Linköping, Sweden Flüssigkeit, 1983, December 1983. RWTH Aachen Dissertation. /23/ F. Yoshida, S. Miyakawa, Effect of Design Parameters on Stability of Water Hydraulic Proportional /4/ S. Rinck, Die Wasserhydraulik entwickelt sich und findet ihre Anwengsbereiche, O+P “Ölhydraulik und Control Valves, Proceedings of 12th International Symposium on fluid Control, Measurement and Pneumatik”, 36 (1992), Nr. 1. Visualization, 18-23 November 2013, Nara, Japan. /5/ R. Kucharzyk, Druck-und Steuer-Sitzventile bis zu großen Nennweiten, O+P “Ölhydraulik und /24/ S. Miyakawa, New Application of Water Hydraulics (Aqua-Drive-System), Proceedings of the 12th Pneumatik”, 36 (1992), Nr. 1. Scandinavian International Conference on Fluid Power, Vol. 2, 27-34, 18-20 May 2011 Tampere, /6/ S. Rinck,Untersuchung und Optimiering schnellaufendr Axial-und Radialkolbenpumpen beim Betrieb Finland. mit wasserbasichen Drckflüssigkeiten, 30. Nobember 1992. RWTH Aachen Dissertation. /25/ W. Backé, H. Baum, Systematik fluidtechnischer Schaltung, Fluidon, Shaker Verlag Aachen 2013. AL

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