Improvements in Water Tube Steam Generators.
Year: 1898

page_text: Date of Application, 2nd July, 1898-Accepted, 15th Oct., 1898
COMPLETE SPECIFICATION.
Improvements in Water Tube Steam Generators.
We, HENRY JOHN CHARLES PATTISON and JOHN ALFRED PATTISON, both of the
Engineering Works, Granili, Naples, Italy, Engineers, 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:-
Our invention relates to certain improvements in steam generators, the object
of same being to provide a generator which is simple in construction, and from
which the tubes may be readily removed externally without displacing any fixed
parts, and one in which they may be readily cleaned from the outside while the
generator is at work. Such a generator also has other advantages which will
appear hereafter.
In the accompanying drawing:
Fig. 1 is an end view of one form of generator one half being in section' and
the other half in elevation.
Fig. 2 is a side view of same partly in section.
Fig. 3 is a section of a part of a generator showing a modification, and
Fig. 4 is a plan partly in section to show certain means which we employ for
opening and closing the ash doors.
According to this invention the generator consists of a steam and water drum
or receiver a and a number of double tubes or generators directly connected
thereto and arranged in a nest or group b. The tubes consist of an inner tube c.
carried or supported inside an outer tube d and having a communication between
same at the lower end as in the well known "Field" tubes. The outer tubes d
are closed at their ends by welding or by means of a plug. These tubes form the
principal generating means and they are preferably arranged in two groups or
nests on an incline over the furnace grate e, the closed ends of the tubes of each
group being opposite doors f through which the tubes may be withdrawn when
removed from the drum or receiver a, and through which cleaning devices may be
inserted. The tubes are also visible through these doors from their lower ends
for all their length. The tubes near their outer end may be supported by passing
through holes in a plate or plates g which may be attached to some part of the
casing. The tubes in this way are so held as to be able to freely expand and
contract, and therefore have little tendency to leak under variations of tempera-
ture. The inner tubes c preferably project into the drum or receiver a and a
diaphragm h is placed near their ends so as to separate the currents in such
receiver, the water passing down the inner or circulating tubes c as shown by the
arrows, and up outside of same in the tubes d from whence it rises up into the
receiver a again inside the diaphragm h, so that a good circulation is maintained.
In place of the diaphragm h the arrangement shown in Fig. 3 may be
employed, the ends of the tubes c being provided with blocks or heads h¹ which
may be of bent sheet metal and which practically touch one another all over the
group so that an obstruction is formed which answers the same purpose as the
diaphragm h. To prevent the heat from the furnace passing too quickly into the

page_text: flue such as j, a perforated baffle plate k may be placed on the far side of the
group of tubes, the holes in such plate being arranged so that the gases are drawn
downwards as indicated by the arrow to find the easiest mode of exit. Or a plain
baffle plate covering only the upper part of the opening to the flue may be
employed instead. Or many of the well known arrangements may be used in
which the gases are caused to pass into the nest or group of tubes and circulates
through them as in a flue before passing out. In the generator illustrated a
steam drum a¹ is arranged at right angles to and communicates with the drum a
for the purpose of obtaining a sufficiency of dry steam.
In order to obtain an abundant supply of air under the grate we provide means
whereby the ash pit doors which are preferably arranged round the boiler may
be simultaneously opened or closed. In Fig. 4 is illustrated in plan an arrange-
ment whereby one half of the doors may be opened or closed at one time though
the arrangement may equally well be adapted for opening the whole of the doors.
It will be seen that the doors m have attached to them ears n through which pass
rods o suitably carried in bearings, such rods being attached to the ears so that
on being rotated they will turn the ears and lift the doors which are hinged on
the upper side in some suitable way. The rods o are operated from a handle p,
the rod o on which such handle is fixed having a segment gear 9 which engages
with a similar gear r on the rod at right angles thereto, there being a similar
arrangement of gears at the opposite corner so that by a movement of the handle
all the doors so connected may be opened or closed at the same time.
It will be understood that the receiver or chamber a may be of any suitable
shape but the cylindrical form shown and the arrangement of the tubes and fire
grate therewith is considered most suitable as there is an absence of flat surfaces
and of stays of every kind which all assist in making the interior of the generator
very accessible.
A rapid circulation is provided by the arrangement of the
tubes, and hence there is no liability for impurities to settle therein.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that what
we claim is:-
1. A steam generator consisting of an inclined group of double or "Field"
tubes forming the principal generating means connected directly to a main drum
or receiver and carried over a furnace, substantially as described.
2. A steam generator consisting of two groups of inclined double or Field"
tubes forming the principal generating means connected directly to a main drum
or receiver carried over a furnace which is between such groups and arranged in
a casing in such a manner that the lower ends of the tubes are opposite doors in
such casing whereby they are accessible for removal or cleaning, substantially
as described.
3. In a steam generator the arrangement of apparatus for opening and closing
the ash pit doors, substantially as described.
4. A steam generator constructed substantially as described and illustrated
in the drawings.
PHILIP M. JUSTICE,
55 and 56, Chancery Lane, London, Chartered Patent Agent,
For the, Applicants.