Valve Construction

[Oldcodger]

I don't know if this article is relevant to forum, but it may be of educational interest to those new to valve construction. Certainly shows how the "grid" arrived at it's name.
A short episode was shown on QUEST (ch37 Freeview, this morning 9.00-9.30AM) on the construction of Audio valves (suggest it was a triode) ("HOW IT'S MADE" S17, EP 7), which should be available on Quest, on demand on the net. The only difference from my education on valve construction was that final evacuation was not done with a bit of magnesium on the (?) heaters to burn off any remaining oxygen.

[greg_simons]

There used to be a film on YouTube by some French guy making replica bright emitter valves, it's probably still there with the right search term.

[mark pirate]

One of the best films on valve construction is 'The Blackburn story'. It is very interesting to see Mullard's production lines.
https://www.youtube.com/watch?v=GDvF89Bh27Y

Mark

[GeeTeeCee]

Originally Posted by greg_simons

There used to be a film on YouTube by some French guy making replica bright emitter valves

This one: https://www.youtube.com/watch?v=EzyXMEpq4qw
Also, making a 1913 Marconi C tube replica: https://www.youtube.com/watch?v=GAMRHcbE3g0
And making tiny tubes: https://www.youtube.com/watch?v=dRI0ZLTP6_0

Originally Posted by mark pirate

It is very interesting to see Mullard's production lines.

Every time I watch that film I'm amazed at the size and complexity of the machinery involved. Those engineering works of art must have required a large team of fitters, turners and allied trades to keep the place going.

And I'm also intrigued by the automation, presumably accomplished by programmed analog computers operated by pneumatics and hydraulics.

[Maarten]

Analog and digital computers. Relay logic, transistor logic, digital building blocks, PLC's, etc.

Philips had ample experience with the carroussel layout for making light bulbs, so they applied that to their automated valve and early transistor production lines as well.

[Oldelectronics]

I really enjoyed that Mark thank you for posting.

Kev

[Mullard]

I worked for Mullard at the Blackburn works in Philips Road in 1967. I worked in Pre-Production and Factory Assistance (PPFA) and was involved in experiments to produce valves using alternative (cheaper) materials, as well as investigating issues with valve assembly that resulting in a higher than normal reject rate. I was a regular visitor to the assembly plants in Lytham, Fleetwood, and Rawtenstall to get assemblies made with the new materials and to bring them back to Blackburn for manufacture into complete valves for testing. The assembly of the valve components was an intricate process, and only girls were employed, as boys had turned out not to have the delicate skills necessary for this process. I got to see first hand all the assembly processes, some of which were fascinating. I am sure there are few outside the industry that realise such things as the complexity of the valve pins and the associated internal connecting wires in glass based valves. I left when I realised that my future was not best aligned with the production of radio valves. I went into computing (software development), which turned out to be a wise decision.

[G8HQP Dave]

You probably have lots of information in your head which people today puzzle over, such as why did they attach the getter 'there' instead of 'there'? What changed inside a valve so it moved from version 1 to version 2?

You mentioned valve pins. I am amazed that a secure vacuum-proof metal-glass seal could be made so cheaply and used routinely in domestic items which can last 60 years or more.

[SteveCG]

Thank you 'Mullard' for saying that Mullard valves were made/assembled in Lytham. I have a dim recollection of a small factory there (mid late 60s) with the Mullard Logo - but later wondered whether I was imagining it !