Improvements in the Manufacture of Glass Tubes."
Year: 1897

page_text: Date of Application, 1st Oct., 1897-Accepted, 11th Dec., 1897
COMPLETE SPECIFICATION.
"Improvements in the Manufacture of Glass Tubes."
I WALTER BUTTERWORTH, of Newton Heath Glass Works, Manchester, in the
County of Lancaster, Glass Manufacturer, Do hereby declare the nature of this
invention and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement:-
--
This invention relates to the manufacture of glass tubes such as are used for steam-
boiler gauges, thermometers, barometers, and the like, the principal object of
the invention being to produce at a moderate price a perfectly transparent glass
tube which shall be more capable of resisting high pressures, and less liable to
fracture from exposure to sudden or extreme variations of temperature, than the
ordinary gauge tubes as hitherto manufactured.
"
The invention consists in the combination of three layers of glass or "metal"
in the manufacture of the tube, in the manner hereinafter described, namely, an
inner thin layer of "lead-casing" glass covered by two subsequent outer layers
of "lime-glass."
The lead-casing" glass is first gathered upon the metal rod or tube in the
usual way and afterwards the two subsequent layers of "lime-glass", and the
triple composite glass thus produced is blown "Marvered" and drawn out in
the usual manner of producing glass tubes. The triple composite tube thús
manufactured will be perfectly transparent, and the different colors of the two
metals" will be separately and distinctly visible at the ends of the tubes.
The innermost layer of "lead-casing" glass is specially adapted to withstand
violent, sudden, and extreme variations of temperature, and being very thin is at
least equal in this regard to the finest and most fragile test tube used for labora-
tory purposes.
The outer layers of "lime-glass" are by their extreme hardness, durability,
and toughness, specially adapted to withstand high pressures of all kinds and to
prevent the super-heated steam from eating into the "metal".
The welding together of three layers, circle within circle, greatly strengthens
the whole tube for the work which it has to do, either as regards variations of
heat or very high pressure.
65
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The two outer layers of "lime-glass" may both be of the same metal or com-
position, but I consider it preferable in some cases to make the second or inter-
mediate coating of glass or
metal of a mean degree of expansibility between
the first and third layers, which may readily be accomplished by a slight variation
in the composition thereof.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what I
claim is: -
1. In the manufacture of glass tubes for water gauges and the like the com-
bination of the three complete cylinders or layers of glass into one composite
tube by welding or fusion in the manner herein before described. and

page_text: Secondly, I claim a glass tube for water gauges and the like, consisting of three
complete cylinders or layers of glass combined together into one composite tube,
the innermost layer of the said tube being distinct in color and composition, and
the complete tube being quite transparent.
Dated this 30th. Day of September 1897.
GEO. DAVIES & SON
Agents for the Applicant, 4, St. Ann's Square, Manchester.