Contribution: Congratulations on the 90th Anniversary
Special Issue of Valqua’s Establishment
Let me express my sincere congratulations on the 90th anniversary specialissue. I have enjoyed reading this journal since 1993 when the journal’sname was different from the current Valqua Technology News（VTN）. At
that time, I met an engineer of Valqua for the first time, when he came to
my workplace at University of Yamanashi to learn about the trends of gasket and sealing
technologies in Europe and the U.S. I am also honored that VTN has published my articles severaltimes.
At that time, non-asbestos gaskets were being developed in the U.S., Canada, the U.K., and France,
but fugitive emissions occurred when the working fluid was a gas. Therefore, researchers wererequested to urgently do the following: introduce new gasket factors, collect data, and, using thegasket factors and collected data, establish methods for designing bolted flange connections which
met the standard leakage rate.
From 1989, I made presentations on my paper at the Pressure Vessels & Piping（PVP）Conferenceof the American Society of Mechanical Engineers（ASME）every year. I also participated in theSpring 2017Bolted Flange Connection Committee（BFC）of the Pressure Vessel Research Council. So, bychance, I grasped the global trends and direction of research. The chairperson of BFC at that time
was Dr. K. H. Hsu, and I had kept a summary of his resume（on a slide）, so I gave a copy to theengineer. After exchanging information with the engineer several times, I asked Mr. Jim Payne, aNo.32

central figure in BFC’s research of bolted flange connection design, about the employee’s questions
while at the PVP Conference in 1994. He gave me his answers which I simply conveyed to theengineer.
Before asbestos regulations were introduced in 2008, asbestos gaskets had been the most widelyused gaskets in Japan. Although I don’t precisely remember the R&D situation for non-asbestos
gaskets at that time, Japan was probably isolated and in a very different environment from that inEurope and the U.S. However, amid such environment, the staff at Valqua studied newtechnologies in the U.S. based on the information summary which I had handed to the engineer andthey prepared for the development of non-asbestos gaskets in Japan.
Around 1997, I was appointed chairman of the Flange-Gasket Committee of the High Pressure
Institute of Japan, so I had more opportunities to learn about research on the sealing performanceof gaskets and bolted flange connections. In 1996, 1998, and 2000, engineers of Valqua participatedin the PVP Conference and gave presentations on their work. Mr. Payne of the U.S. had highexpectations for their presentations on gasket technologies. I also conducted several joint
researches with Valqua during my tenure at University of Yamanashi and Hiroshima University.
15Valqua also received the attention of researchers from a major US petroleum company when
Valqua more recently presented papers at the PVP Conference related to our joint research on theanalysis of the mechanical behavior and sealing performance evaluation of bolted flange
connections with PTFE gaskets, as well as the stress analysis and sealing performance evaluationof bolted flange connections with larger nominal diameter.
The major research trends in Europe and the U.S. at present appear to be as follows: to develop
techniques for detecting fugitive emission amounts at levels ranging from 10−7 to 10−9 Pa m３/s and,due to environmental problems, to establish methods for the design and construction of bolted
flange connections. In addition, research and technological development of not only gaskets but
also overall bolted flange connections for establishing the following methods are required: amethod to design bolted flange connections and to develop gaskets for high-temperatureenvironments when a combined external load is applied; an efficient and reliable multiple-bolttightening method; and a method for preventive design and assembly for bolted flange connections
with larger nominal diameter. That is, the design and assembly of bolted flange connections

I believe that Valqua will continue to lead the world in the development and expansion of sealing
technologies.
Professor Emeritus at the University of Hiroshima

Toshiyuki Sawa

16

Spring 2017

including a more reliable bolt tightening method than the standard leakage rate is required.

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