IMPROVEMENTS IN THE CONSTRUCTION OF STEAM BOILERS AND MACHINERY FOR PROPELLING VESSELS
Year: 1843

page_text: TO ALL TO WHOM THESE PRESENTS SHALL ME, I, JAMES
JOHNSTON, of Willow Park, Greenock, Esquire, send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Letters Patent under the Great Seal of Great Britain; bearing date at West-
minster; the Twenty-fifth day of May, in the sixth year of Her reign, did, for
Herself, Her heirs and successors, give and grant unto me, the said James
Johnston; Her especial licence, full power, sole privilege and authority, that I,
the 'said James Johnston, my exors, adñors, and assigns, or such others as I,
the said James Johnston, my exors, adiñors, or assigns, should at any time
agree with, and no others, from time to time and at all times during the terms
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 IN THE CONSTRUCTION OF STEAM BOILERS AND
MACHINERY FOR PROPELLING VESSELS;" in which said Letters Patent is contained
a proviso, that I, the said James Johnston, shall cause a particular description
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
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 there-
unto had, will more fully and at large appear.

page_text: NOW KNOW YE, that in compliance with the said proviso, I, the said
James Johnston, do hereby declare that the nature of my said Invention, and
the manner in which the same is to be performed, are fully described and
ascertained in and by the following statement thereof, reference being had to
the Drawings hereunto annexed, and to the figures and letters marked thereon,
that is to say-
IMPROVEMENTS IN THE CONSTRUCTION OF STEAM BOILERS.
The improvements in boilers which I claim as new and original have refe-
rence to a particular kind of water space; therefore, in order to render plain
and intelligible those improvements, I shall describe the kinds of water spaces
at present in use. Water spaces in boilers may be divided into two grand
divisions: first, those formed of tubes or cylinders of metal; second, those
formed of plates of metal. The first of these grand divisions is divisible into
two minor divisions: first, those boilers in which the water space is within the
tubes; this I call the circular water space: second, those boilers in which
the water space is between the tubes (as in the common locomotive boiler);
this I call the honeycomb water space, from the resemblance which a section
of it bears to that substance. The second grand division of water spaces,
videlicet, those formed by plates of metal, I call sheet water spaces, from the
fact of the water being divided into sheets or plates by the flues; this is owing
to the flues being made (more or less correctly) after the shape of a parallelo-
gram. The common marine boiler is an example of this kind; the flues of it
divide the water in the boiler into sheets or plates. My improvements have
reference only to the sheet water spaces. It is no matter what kind of metal
be used, or what particular shapes the flues may be of, provided that the water
between them is divided into plates or sheets. It is the using of those sheet
water spaces, in accordance with a system of working hereafter to be described,
which forms the peculiarity of my improvements in boilers.
DESCRIPTION OF THE DRAWINGS.
Figure 1 represents a horizontal section through the centre of the boiler.
Figure 2 represents a perpendicular section across the centre of it. In both
these Figures the shaded parts represent the flues, with the water spaces
between them, for the ascending currents of water. A, B, A, B, are the
water spaces for the descending currents. The area of the water space for the
descending current should be equal to the area of the water space for the
ascending current. If room can be given, the boiler will work better.by
having the area of the descending current the largest of the two.
If the area
of the descending water space be made less than the area of the ascending

page_text: water space, it will diminish the strength of the current, and destroy its useful
effect. C, D, is the water line when the water is not heated. The curved line
F, G, H, represents the shape which the surface of the water assumes when
it is boiling. In the plans I have not drawn either a furnace or a chimney,
because in them I have no improvements to make. A furnace and chimney
of any description may be adapted to this boiler; the only point requisite is,
that they be so placed that all the heated products of combustion from
the furnace be made to pass through the flues in the interior of the boiler.
Figure 3 represents on a large scale a section of one of the flues. It is
constructed by riviting face to face, at top and bottom, the sheets of metal of
which it is composed. All boiler flues are at present constructed by over-
lapping the plates, and then riviting them.
I claim as new and original the making of boiler flues the tops and
bottoms of which are formed by rivetting the plates face to face, no matter
whether there be or be not a strip of metal or other substance interposed
between the faces of the rivitted plates similar to that represented by the
pieces marked L in Figure 4. Boiler makers, in placing the interior arrange-
ments either of a marine or locomotive or any other boiler with internal flues,
always go by the following rule, videlicet, that the whole water space of a
boiler should be filled with as many flues as it is possible to get inserted within
it. The avowed object of this is, that they may keep the whole of the water
in the boiler at as nearly as possible a uniform temperature, and also for the
purpose of obtaining a great extent of heating surface. Now I deviate from
the above plan in so far that I devote a certain portion of the water space of
my boiler for the purpose of being occupied with flues, and another portion of
the water space I leave without flues. (In Figures 1 and 2, the parts A, B,
of the water space are without flues.) I do this in order to obtain in my
boiler water of different temperatures, and by so doing I find that I have a
strong, current of water always circulating through the boiler. The current of
water ascends up between the flues, and then descends in the parts of the boiler
where there is no flues. This current of water I find to be of such strength
that no deposit of fur or sediment occurs upon the flues, even although the
water in the boiler is saturated with saline or earthy matter, provided that the
flues are constructed so that the current of water can act freely on all their parts.
In the common marine boiler, where salt water is used, the water spaces
between the flues are never narrower than two inches; from three to four
inches is about the ordinary breadth. Now in my boiler the water spaces
may be made as narrow as half an inch, without the slightest danger of, a
deposit of salt occurring in them, or of their being exposed to danger from the

page_text: water being thrown out of them. Those advantages are gained in consequence
of the current of water, which is continually rushing up between the flues with
such force that it is impossible for salt to be deposited on them, or for them
to be left without water, as long as the water in the boiler is kept.at its proper
level. In constructing a boiler according to my plan, it is not absolutely
necessary
that the narrow flat flues and water spaces should be placed (as in
the plan) exactly in a perpendicular position, nor is it absolutely necessary
that they should be perfectly straight, although in constructing boilers I always
intend to make the flues straight, and to place them and the water spaces in a
perpendicular position, because the strength and consequently the utility. of
the current of water, depend upon its upward progress between the flues being
uninterrupted.
Although I have claimed as new and original the peculiar méthod of
forming boiler flues by riveting face to face at top and bottom the plates
of which the flues are made, yet that plan of making flues is not essential
to the working of my boiler; any flat flues that will divide the water into
narrow sheets will answer the purpose. Simplicity and great ease of con-
struction are the advantages which my flues possess over the common kind.
Finally, this boiler is applicable for and is intended to be used instead of the
various kinds of steam engine boilers at present in use, either on land or sea.
In the constructing of this boiler I desire to limit myself only by what may be
considered to be the fair meaning of the following paragraph, together with:
the explanations already given of the plans.
I wish it to be distinctly understood that I do not claim as new and original
the forming or using of ascending and descending currents of water in boilers.;
but that I claim as new and original the devoting the spaces between the flues
to the ascending currents, always bearing in mind that my claim has only.
reference to such boilers as have upright, sheet water spaces between the
flues.
In witness whereof, I, the said James Johnston, have hereunto set my
hand and seal, this sixth day of October, in the year of our Lord One
thousand eight hundred and forty-three.

page_text: In the Matter of a Patent granted to James Johnston, of Willow Park,
Greenock, Esquire, for his Invention of "Improvements in the
Construction of Steam Boilers and Machinery for Propelling
Vessels," bearing date at Westminster, the Twenty-fifth day of May,
One thousand eight hundred and forty-three.
:..
DISCLAIMER AND MEMORANDUM OF ALTERATION proposed to be
entered by James Johnson with the Clerk of the Patents of England,
_ pursuant to an Act passed in the fifth and sixth year of the reign of His
late Majesty King William the Fourth, intituled "An Act to amend the
Law touching Letters Patent for Inventions.".
I, the said James Johnston, do declare that since I obtained the said Letters
Patent I have discovered that the Invention which was intended to have been
described under that part of the title which is contained in the following
words, "and machinery for propelling vessels," is not of such practical utility
as would make it desirable to retain it in the said Patent, for which reason I'
am desirous to and do hereby disclaim all that part of the title which is contained
in the following words, "and machinery for propelling vessels."
In witness whereof, I, the said James Johnston, have hereunto set thy
hand and seal, this Sixth day of October, in the year of our Lord One
thousand eight hundred and forty-three.

page_text: William Henry Ritchie, of Lincoln's Inn, in the County of Middlesex,
Gentleman, maketh oath and saith, that he is acquainted with the hand-
writing of Mr. John Denniston, and that he has examined the Specification of
a Patent granted to Mr. James Johnston, of Greenock, and that he believes
the signature affixed thereto to be the signature and handwriting. of the
aforesaid John Denniston, and he has been informed and verily believes that
he was a Justice of the Peace for Renfrewshire at the time such signature
was made