Improvements in Steam or other Fluid Boilers.
Year: 1893

page_text: Date of Application, 24th July, 1893
Complete Specification Left, 31st Jan., 1894-Accepted, 7th Apr., 1894
PROVISIONAL SPECIFICATION.
Improvements in Steam or other Fluid Boilers.
I, LUDLOW PATTON PERKINS, of No. 113, Acomb Street, Moss Lane East,
Manchester, in the County of Lancashire, Engineer, do hereby declare the nature
of this invention to be as follows:-
My invention relates to improvements in the construction of apparatus for the
generation of steam or other motive vapour or gas from any liquid or liquids.
It consists in a combination of one or a number of separate hermetically sealed
tubes with any suitable source of heat, and a vessel or vessels, shell or shells, tube
or tubes suitable for containing liquid or liquids to be evaporated for any
subsequent purpose-under pressure or otherwise.
The following arrangement may be taken as a typical one and descriptive of
the nature of the invention. A number of tubes containing a certain quantity of
liquid and hermetically sealed are placed vertically (or at any suitable angle)
above a fire or other suitable source of heat and passing through the shell of a
vessel or boiler containing the liquid which it is desired to evaporate.
The action is as follows-The heat of the fire (or other source of heat) being
applied to the lower portions of the tubes is rapidly transmitted through them to the
liquid contained in the boiler, by the agency of the liquid contained in the tubes,
which becoming partially evaporated, ascends giving out its sensible heat, and in
condensing its latent heat to the liquid in the boiler, the condensed liquid
descending to be again evaporated. The escaping products of combustion or other
source of heat, may if thought desirable be made to pass through the boiler or
vessel in tubes or flues or around it through any ordinary flue or flues or through
both. When these tubes are fitted to an ordinary boiler they may be so arranged
as to withdraw the intense heat of the gases or products of combustion before they
come into contact with the ordinary heating surface, thereby obviating any
possible overheating of plates and consequent leakage and thus permitting higher
rates of combustion to be employed than heretofore.
These tubes may be inserted and made tight in the plate or shell of the vessel
containing the liquid to be evaporated in any suitable manner, for instance by
screwing and caulking, or by providing suitable cones or metallic surfaces which
can be drawn up into or against the shell by nuts or other means.
In some cases it may be advisable to surround the portion of the tubes within
the vessel or boiler with tubes or shields provided with suitable apertures with a
view to promote a rapid circulation of the liquid surrounding them. These tubes
or shields may be used as distance pieces or stays, or the tubes themselves may be
made to act as stays. The quantity of liquid contained in these closed tubes
should be varied to suit the conditions under which they work, and should
in most cases not be less than about of their internal volume, or else all
the liquid may be converted into steam or vapour which will greatly lessen
their efficiency as conductors, owing to the fact that a comparatively feeble
circulation of superheated steam will be set up, instead of rapid conversions first
of a liquid into a vapour accompanied by a large absorption of heat from the fire
and then from a vapour to a liquid with an equivalent surrender of heat to the
water contained in the boiler.
By constructing boilers in the manner as herein before described the following
advantages are derived. Should the failure of any one or any number of these
tubes occur it cannot produce disastrous results, or allow the water in the boiler or
vessel to escape, whether the burst occurs within or without the vessel or boiler.

page_text: Any deposit or scale forming on the portions of the tubes in the boiler or vessel
will as it thickens allow their temperature to increase and consequently cause them
to expand thereby cracking off the scale or deposit which will fall on to the
bottom plate of the vessel, which may be protected by the tubes passing through
it, and which will therefore not be readily overheated or burnt away. The broken
scale can then be readily removed through a suitable man or hand hole. These
tubes may be so arranged as to form the sides or ends of a firebox or bent in such
a manner as to form fire bars, or in any manner proper to their working to suit the
type of boiler required.
Dated this 22nd day of July 1893.
PHILLIPS & LEIGH,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Steam or other Fluid Boilers.
I LUDLOW PATTON PERKINS of 113 Acomb Street, Moss Lane East,
Manchester, in the County of Lancaster, Engineer, 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 and accompanying
drawings :-
My invention relates to improvements in the construction of apparatus for the
generation of steam or pressure vapour and has for its object to increase the
efficiency of such apparatus and to remedy existing defects therein.
I employ a number of separate hermetically sealed tubes each partially filled
with liquid in combination with a vessel or chamber or a series of connected vessels
or chambers containing the liquid to be evaporated.
The accompanying drawings illustrate the manner in which I propose to carry
my invention into effect.
In the drawings,
Fig. 1 is a longitudinal section of a steam boiler.
Fig. 2 is a cross section through the fire grate of the same.
Figs. 3, 4, 5 and 6 on Sheet 2 are details of the sealed tubes.
Referring to Figs. 1 and 2 a number of tubes a a each containing a quantity of
liquid and hermetically sealed are vertically disposed in the furnace b and flue c.
The upper ends of the tubes pass through the shell of the vessel d and are made
tight where so passing through in the manner hereinafter described and illustrated
in Fig. 6, Sheet 2.
The vessel d contains the liquid to be evaporated and the line e e indicates the
normal liquid level.
The fuel is introduced through the firedoor g onto the firebars h, the necessary
air for combustion being admitted through the door j. The door k provides means
for sweeping the outer surfaces of the tubes and for admitting cold air if it is
desired to check the generation of steam. At 7 is an ordinary bridge and at ma
door providing access to the flue c. The tubes immediately above the hottest
part of the fire are shorter and consequently have less exposed surface than
those on either side or in the flue. To enable the indicated form of shell to
withstand internal pressure the tubes are made to act as stays, and the portions of
the tubes above the level of the liquid serve to dry the steam, and to superheat it
to some extent. The ends of the boiler may be stayed or strengthened in any
ordinary manner. The shell may be of any suitable form other than the form
illustrated and the tubes may be disposed at any angle or angles which will allow
the liquid contained to gravitate to the lower ends, or the tubes may be bent in
such a manner as to act as firebars, or to constitute the sides or end of a firebox.

page_text: The heated gases may be made to pass around the shell, or in any other direction,
but it is preferable that the hottest gases shall come into contact with the tubes,
before such gases come into contact with the ordinary heating surface of the
boiler.
The quantity of liquid put into the tubes should be such as that all the liquid
contained in the tubes cannot be entirely converted into vapour, which would
lessen the efficiency of the tubes as conductors and permit the tubes to become
overheated owing to the fact that a comparatively slow circulation of superheated
vapour would be set up instead of a series of rapid conversions, first of a liquid
into a vapour accompanied by a large absorption of heat from the fire, and then
from a vapour into a liquid with an equivalent surrender of heat to the water
contained in the boiler. When it would be desired to generate steam of such
pressures as are generally now in use, say 100 to 150 pounds per square inch and
when the combustion of the fire would be under the conditions of natural draught,
I should prefer that about one fourth of the internal volume of the tube shall be
filled with liquid, and that if oue foot in length of the tube be immersed in the
liquid in the boiler or vessel three feet shall be exposed to the action of the furnace,
or source of heat.
I have found that it is not advisable in any case that the quantity of liquid
within the tube shall be less than about one sixth or more than about three quarters
of the capacity of the tube. The liquid which I prefer to use is water, but I
do not confine myself to this liquid as it may be advantageous to employ spirits
hydro carbons or other liquids which have higher or lower boiling points or which
better resist the effects of frost.
I have found it advantageous in certain cases particularly when tubes are
working at low pressures and temperatures to exhaust them of air as far as
practicable.
The action of the apparatus is as follows.
The heat applied to the lower portions of the tubes is rapidly transmitted
through them to the liquid contained in the boiler by the agency of the liquid
contained in the tubes, which becoming partially evaporated ascends giving out its
sensible heat, and in condensing its latent heat to the liquid in the boiler, the
condensed liquid contained within the tubes descending to be again evaporated. By
suitably proportioning the tubes the internal pressure may be so regulated as to
always insure that the contained liquid shall be kept in contact with the interior of
the length of the tube exposed to the furnace even with higher temperatures than
are generally employed.
Fig. 3 illustrates a method of fixing the tubes in cases wherein it is not
convenient to carry the tube through the two shell plates a and b. In this example
the joint is made by means of a cone c drawn by a back nut d into a hole e drilled
through the plate a having the edge of such hole faced or prepared to be sharp
and true.
Fig. 4 shows a tube screwed through the two plates and made to act as a stay the
thread being rendered tight by caulking at g and h. This method is suitable for a
permanent fixture.
Fig. 5 is an arrangement in which the tube is carried through both plates, the
joint being made in a similar manner to that in Fig. 3 but the nut is on the
outside of the plate b and makes the joint on that plate by reason of its being
screwed hard down upon the plate the lower edge of the nut being sharpened so as
to make a narrow netallic joint at l. A circulating tube m provided with suitable
apertures n n for the passage of the liquid surrounding the tubes, acts as a distance
piece between the plates a and b.
Fig. 6 illustrates the method of fixing the tubes shown in Figs. 1 and 2 Sheet 1.
I prefer this method as it is more easy to tighten the joints should they leak or to
remove or replace a tube. The joint at o is made in the same manner as the
one in Fig. 3 but the cone p is inside the boiler and the nut q outside. The hole
in the plate is sufficiently large to allow the cone p to pass through and is screwed

page_text: to receive the screwed enlargement s formed upon the tube. A plug nut something
similar to k in Fig. 5 is screwed upon the enlargement s and is brought down upon
a ring of copper or other suitable material so as to secure the joint.
22
The plug nut may be sharpened on its lower edge as at 7 in Fig. 5.
By constructing steam generators in accordance with my invention the following
principal advantages are obtained.
I have found that these tubes evaporate more liquid than an equal amount of any
ordinary heating surface.
The failure of one or any number of these tubes cannot empty the boiler whether
the failure occurs within or without the shell and need not therefore necessitate the
stoppage of the boilers.
Liquids containing large quantities of sedimentary matter may be used in the
generation of steam because any deposit of scale forming upon the tubes will be
-only upon their external surfaces and will by increasing in thickness allow their
temperatures to rise and thereby to crack and detach the scale or sediment which
will fall to the bottom of the water space whence it can be readily removed.
I would have it understood that I am aware that it has been proposed to use
hermetically sealed tubes charged with minute quantities of liquid in the generation
of steam but on the application of heat to tubes so charged it has been found that
they become red hot thereby proving that the superheated or surcharged steam
entirely filling such tubes has not constituted a sufficiently rapid medium for the
transferrence of heat. I am also aware that with a view of obviating this fatal
defect apparatus known as "Perkins' High Pressure Hot Water Heating Apparatus'
has been used in connection with steam boilers but in such apparatus water has
been caused to circulate through closed tubes outwardly exposed to the water to be
evaporated and to the heating furnace.
I do not therefore claim the use of the sealed tubes excepting when charged and
applied in the manner substantially as hereinbefore set forth.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed 1 declare that what I
.claim is.
1. A steam generator constructed and adapted to act as set forth and indicated.
2. The hermetically sealed tubes charged with liquid applied to fixed and
secured in steam generators substantially as and for the purpose set forth and
indicated.
3. In steam generators of the indicated nature the methods of securing the tubes
to the plates and of making tight joints therewith substantially as set forth with
reference to the figs. on Sheet 2.
4. In a steam generator the hermetically sealed tube containing liquid formed
applied and secured to the shells or plates of the generator substantially as set forth
with reference to Fig. 6 of the drawings.
Dated this 30th day of January 1894
E. K. DUTTON & Co.,
5, John Dalton Street, Manchester, Agents.