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Valerian P. Shumilov
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Moscow, SU
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last 30 patents
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Patent Grant
Multistage helical down-hole machine with frictional coupling of wo...
Patent number
4,585,401
Issue date
Apr 29, 1986
Veesojuzny Ordena Trudovogo Krasnogo Znameni Naucho-Issle
Dmitry F. Baldenko
E21 - EARTH DRILLING MINING