IMPROVEMENTS APPLICABLE TO BOILERS OB APPARATUS FOR GENERATING STEAM
Year: 1843

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, DAVID
NAPIER, of York Road, Lambeth, in the County of Surrey, Engineer, send
greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Letters Patent under the Great Seal of Great Britain, bearing date at
Westminster, the Twenty-fifth day of July, in the seventh year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said David Napier, Her especial licence, full power, sole privilege and
authority, that I, the said David Napier, my exors, admors, and assigns, or
such others as I, the said David Napier, my exors, admors, or assigns,
should at any time agree with, and no others, from time to time and at all
times during the term of years therein expressed, should and lawfully might
make, use, exercise, and vend, within England, Wales, and the Town of
Berwick-upon-Tweed, my Invention of "IMPROVEMENTS APPLICABLE TO BOILERS
OB APPARATUS FOR GENERATING STEAM;" in which said Letters Patent is con-
tained a proviso that I, the said David Napier, shall cause a particular descrip-
tion of the nature of my said Invention, and in what manner the same
is to be performed, to be inrolled in Her said Majesty's High Court of Chancery

page_text: within six calendar months next and immediately after the date of the said
in part recited Letters Patent, as in and by the same, reference being
thereunto had, will more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
David Napier, do hereby declare that the nature of my said Invention, and in
what manner the same is to be performed, are fully described and ascertained
in and by the following description thereof, that is to say :-
The design of my Improvements applicable to Boilers or Apparatus for
Generating Steam is, for the prevention of the water passing off' in conjunction
with the steam, or what is technically called priming or flushing, and is obtained
in the following simple manner, namely, by covering the surface of the water
in the boiler or generator with one or more tiers (as the case may require) of
buoyant substances, such as hollow metallic balls, or by substances that are not
buoyant, supported by any mechanical means in the interior of the boiler or
generator; and while I do not confine myself to any particular shape or size
for these substances, yet I do much prefer the spherical form (from one and a half
to two inches diameter), seeing they always tend to preserve the level, presenting
at the same time numerous and regular interstices for the steam to pass
through; neither do I confine myself to any one material of which these
spheres should be made; yet I may mention that, where they can conveniently
be supported on wire gratings or any other mechanical means, wood answers
the purpose tolerably well. As a buoyant substance hollow glass balls answer
well, with the exception they are too fragile where there is much ebullition. I
therefore give the preference to thin metallic balls. It will be obvious that the
effect produced by these balls must be first to still the water, so as to prevent
it from rising up in quantities with the steam; and, secondly, that the surface
of the upper tier of balls will serve to intercept the smaller particles of water,
and so allow the steam to blow off comparatively dry.
What I do claim, therefore, as my Invention is, the peculiar methods above
described for preventing priming or flushing, of whatever form or material the
substances employed may be made, and whether buoyant or supported in or
above the water.
In witness whereof, I, the said David Napier, have hereunto set my
hand and seal, this Twenty-fourth day of January, in the year of our
Lord One thousand eight hundred and forty-four.
DAVID (L.S.) NAPIER.

page_text: AND BE IT REMEMBERED, that on the Twenty-fourth day of January,
in the year of our Lord 1844, the aforesaid David Napier came before our
said Lady the Queen in Her Chancery, and acknowledged the Specification
aforesaid, and all and every thing therein contained and specified, in form
above written. And also the Specification aforesaid was stamped according to
the tenor of the Statute made for that purpose.
Enrolled the Twenty-fifth day of January, in the year of our Lord One
thousand eight hundred and forty-four.