Thanks Andrew, now I understand what they're for but where exactly were the
cross arms or arch heads located? Were they fixed to the beam? On the famous
Perran Foundry cross section for example (printed in Barton and elewhere)
the cylinder end of the beam on the in-house stroke is below the top of the
spring beam. Is the cross arm not shown on this drawing?
Thanks for your help
Phil Newman
-----Original Message-----
From: Andrew Hurrell [mailto:[log in to unmask]]
Sent: Friday, August 29, 2003 6:54 PM
To: [log in to unmask]
Subject: Re: Spring beams
The spring beams on a non-rotary beam engine are there to act as a buffer.
If the engine hits the bottom of the cylinder on the 'in-house' stroke or
the top of the cylinder (and bottom of the pumps) on the 'Out of House'
stroke there is a good chance that the engine will smash the cylinder
casting. This could be because of something like a pump rod breaking or the
valve gear not operating properly.
Cross arms ('Arch Heads' ?) raised above the ends of the beams line up with
the spring beams. When the engine is working correctly, the arch heads
should stop just short of the spring beams.
The Dorothea engine, because the pump rods are missing, is sat on the spring
beams inside the engine house. The beams in this case start under the
bearings and can clearly be seen to be smaller than the structural beams
below.
Regards
Andrew
----- Original Message -----
From: "Newman, Phil" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Friday, August 29, 2003 11:10 AM
Subject: Spring beams
> Dear list,
>
> Could someone please provide a concise definition of a Spring Beam. Most
> diagrams of engine houses in the usual sources show them and the sockets
are
> usually quite evident in the structures but there precise function is not
> fully clear to me.
>
> Thanks in anticipation
>
> Phil Newman
>
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