(003W-3)

Tube Making Recordby T. Umeda, General Foreman,Receiving Tube Department, TEC(1976) in Japanese (English version: by Sash Ohtsuka)- 3 Pages
1.

It was 1916 when we started research on vacuum tubes. The first one was UN-100,
Audion type which completed in 1919*1. In the same year UF-101, French type, wasalso completed.

2.

It was a small scaled production in a room in the research department up to 1923.
In the same year private wireless telegraph/ telephone regulation was effected, andexperiment in radio broadcasting has commenced, and matching such a demand,
production of UV-200 and UV-201 has started. ------- excluded latter part: ed.

A.

Audion Valve (UN-100) completed in 1919*1
Cathode (filament) was of pure Tungsten wire, grid was two pieces of Nickel wireof 0.6mm dia., formed with tweezers and scale, anode was also two pieces of Nickel sheet
cut with scissors to the required size. Those were quite inaccurate ones. Glass bulb wasin a spherical shape, both-ends were sealed, and only cathode end was terminated witha metal base. For other leads, rubber tubes were inserted for insulation.
Treating metal parts: after removing unwanted matters with benzene, treated in thehydrogen furnace.
Exhaust and aging: Heat the bulb at 350oC for 10 minutes. At that time, there wasno high-frequency electric furnace available, and therefore exhausted occluded gas in
the electrodes with electron bombardment during exhaust process. It was easily seen
deformed electrodes. We used red-phosphoric getter solution painted inside exhausttubing, and heated with a burner during exhaustion for accelerate the process.
Aging process was completed during exhaustion. After exhaust process, conducted
performance test, and then installed a base only for good products.
In exhaust process, we used an oil rotary pump for back up of mercury diffusion
pump made of glass. Also cooled the glass trap with salt and ice.

Note: *1: According to other information like the list (001L), completion date of Audion
should be in 1917. The editor guesses 1919 must be the year in which it wastransferred from laboratory to production department.

1Note: Filament is a reversed-V shape with a center supporting rod ----- Ed..

B.

French type (UF-101) in 1919
This tube was a more improved type than Audion. Cathode was pure Tungsten, grid
was a spiral coil without side rod. It was made by hand winder, and material wasMolybdenum. Anode was cylindrical shaped Ni sheet made by press. This type had
demand from government for quite long period, and produced approx. 1,500 pieces
annually if I recall. The bulb was spherical.

2C.

UV-102 in 1920
Cathode was pure Tungsten, grid was spiral, side rod was Ni wire of 0.75mm
dia., wound by hand grid machine and welded to side rod. Anode was cylindrical,material was Ni. Form to specified dimension after pressed, same as in UF-101.
The treatment of metal parts and exhaust process are about same as UF-101.

D.

UV-200 and UV-201 in 1923
Cathode was pure Tungsten and formed to V-shape in both types. Grid was flat
type with two side rods, and grid wire was Mo, side rods were Ni. Wound by hand
grid machine and welded to side rods. Anode was flat type, Ni sheet, formed torequired size after pressed. Treatment of metal parts, exhaust and aging processes
are almost same as in UV-102. Only difference was that UV-200 was a soft valve,
and therefore filled with Argon gas, so-called soft valve whereas UV-201 was a hardvalve.

Note: Could not put a photo copy of these types
as they are not in our database now. I
feel that Japanese made types seem nodifference between the original ones. ---- Ed.
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