| The first helium liquefier in Japan was installed in 1952 at the Low Temperature Lobratory (the predecessor of Center for Low Temperature Science at present), in Institute for Materials Research (IMR), Tohoku University. This was the start of the low temperature science researches in Japan. The liquefier now working in this center is the fourth one. Here we briefly introduce the helium liquefiers in the past and now in Tohoku University. | |
|
ADL Collin's type liquefier First Helium Liquefier in Japan (1952-1970) According to the early recognition about the importance of material research at low temperatures, IMR introduced the Collins-type helium liquefier (made by A.D. Little Ltd., USA) for the first time in Japan in 1952. This machine, having a liquefaction capacity of 4 liters/h at that time, made a great many contributions to the developments of low-temperature scientific researches at Tohoku University. Later the capacity was raised up to 8 liters/h due to the increase of the compressor. (Total amount of liquefaction: 21,300 liters, Average:800 liters/year) |
|
|
Nippon Sanso LHE60 (1971-1992) In order to satisfy the demands of liquid helium (L. He) from the many users in Tohoku University, which had increased year by year, Cryogenic Center was organized from the section of helium liquefaction in IMR with a renewal of the liquefier. This second liquefier, made by Nippon Sanso K.K, Japan, had a capacity of 60 liters/h with the reciprocal expansion engines and a external helium gas purifier. According to this, the supply of L. He to all the laboratories and the faculties became possible. (Total amount of liquefaction: 1,132,600 liters, Average: 38,000 liters/year) |
|
|
Linde TCF 50 (1993-2009) Due to the frequent machine troubles after use of more than 20 years and the further increase in the demands of L. He, the new powerful liquefier was desired. Thanks to the great efforts of the related staffs, the liquefier was renewed again in 1992. This third machine, TCF 50, made by Linde cryogenics LTD., England, has a capacity of 150 liters/h, which is 2.5 times higher than the pervious one, with the gas bearing turboexpanders and a internal purifier. Athough small troubles sometimes started to happen from 2006, the system had been continuing the stable supply of L. He with 155,000 liters/year maximum until 2009. (Total amount of liquefaction: 1,556,000 liters, Average: 97,000 liters/year) |
|
|
Linde L 280 (2010-present) Because of the demands of L. He that continued increasing, the helium liquefying facilities with higher performance had been necessary. Fortunately the budgetary request for them was accepted in 2009, and we renewed the system having the L280 liquefier with a capacity of 200 liters/h as a main facility. This system is also equipped with a liquid helium pump, which enables us to transfer 100L liquid helium into a carrying container in 5 minutes, leading to shortening of time for delivery service. However, it has been tuned out for a while that the internal purifier of this fourth machine is not so effective for the removal of hydrogen, resulting in the serious problem that the liquid helium is contaminated by particles of solid hydrogen. Although the this problem remains unsolved completely, the amount of solid hydrogen tends to decrease now by devising the operation method. (Average liquefaction: 97,000 liters/year) |
|