An Improvement in and relating to Water Tube Boilers.
Year: 1897

page_text: Date of Application, 25th May, 1897
Complete Specification Left. 24th Feb.. 1898-Accepted, 7th May, 1898
PROVISIONAL SPECIFICATION.
An Improvement in and relating to Water Tube Boilers.
I, ALFRED FERNANDEZ YARROW, of Isle of Dogs, Poplar, in the County of London,
Engineer, do hereby declare the nature of this invention to be as follows:-
In a boiler having water tubes arranged in rows, the tubes in each row separated
by intervals through which the combustion gases pass, these gases as they pass
through the successive rows become more or less cooled, being at a lower
temperature when they act on the last rows of tubes than when they act on the
first which they meet in their course. Again as the water circulates generally,
through all the tubes, the temperature of the water in the tubes last acted on by
the combustion gases is as high or nearly as high as that of the water in the tubes
first acted on. As the amount of heat imparted by the gases to the water during
their passage depends in great measure on the excess of the temperature of the
gases over that of the water, it follows that the rows of tubes last acted on by.
the cooler gases, having their contents at a temperature nearly that of the gases
themselves are less efficient for heating water than they would be if their con-
tents were cooler.
The object of my invention is so to arrange the feed and circulation of the water
of a water tube boiler as to increase the heating efficiency of those sets of the tubes
which have their efficiency lessened by the conditions to which they are usually
subjected as above stated.
For this purpose, I separate a row or several rows of the tubes or several of the
tubes last acted on by the combustion gases from the general circulation of
the boiler, and supply them with the feed water so that their contents have a
temperature considerably below that of the gases already more or less cooled by
passing the other tubes and are therefore in condition to receive more heat from
these gases in their passage. The feed water may be supplied to the steam and
water drum at the top of the boiler, but into a compartment immediately over
the mouths of the outer tubes separated from the rest of the drum by a partition
extending above the water level. Thus the feed water has to descend the tubes
last acted on by the combustion gases to the water chamber below where it joins
in the general circulation.
According to another arrangement, the row or rows of the tubes last acted on
by the gases may spring from a water chamber at the bottom separate from that
from which the other tubes spring. This separate chamber is supplied with the
feed water which thus is made to ascend the tubes last acted on by the combustion
gases to the steam and water drum above where it joins in the general circulation.
The outer tubes thus supplied with the feed water practically operate as a feed
water heater, utilising much of the heat still remaining in the combustion gases
before they pass to the chimney.

page_text: I, ALFRED FERNANDEZ YARROW, of Isle of Dogs, Poplar, in the County of London,
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:-
-
In a boiler having water tubes arranged in rows, the tubes in each row separated
by intervals through which the combustion gases pass, these gases as they pass
through the successive rows become more or less cooled, being at a lower
temperature when they act on the last rows of tubes than when they act on the
first which they meet in their course.
Again as the water circulates generally through all the tubes, the temperature
of the water in the tubes last acted on by the combustion gases is as high or nearly,
as high as that of the water in the tubes first acted on.
As the amount of heat imparted by the gases to the water during their passage
depends in great measure on the excess of the temperature of the gases over that
of the water, it follows that the rows of tubes last acted on by the cooler gases,
having their contents at a temperature nearly that of the gases themselves are less
efficient for heating water than they would be if their contents were cooler.
The object of my invention is so to arrange the feed and circulation of the water
of a water tube boiler as to increase the heating efficiency of those sets of the tubes
which have their efficiency lessened by the conditions to which they are usually
subjected as above stated.
For this purpose, as shewn in the accompanying drawings each of which is a half
vertical section of a water tube boiler of known form, I separate a row or several
rows A of the tubes or several of the tubes last acted on by the combustion gases
from the general circulation of the boiler, and supply them with the feed water
so that their contents have a temperature considerably below that of the
gases
already more or less cooled by passing the other tubes, and are therefore in condition
to receive more heat from those gases in their passage. As shewn in Fig. 1 the
feed water may be supplied by the valve F to the steam and water drum S at
the top of the boiler, but into a compartment C situated immediately over the
mouths of the outer tubes A A and separated from the rest of the drum by a parti-
tion P. Thus the feed water has to descend the tubes A which are last acted on
by the combustion gases to the water chamber W where it joins in the general
circulation.
"
According to a modification shewn in Figs. 2 and 3, the row or rows A of the
tubes last acted on by the gases may spring from a water compartment C at the
bottom separate from W from which the other tubes spring.
This separate compartment which may be inside the chamber W, as shewn in
Fig. 2, or outside, as shewn in Fig. 3, is supplied with the feed water which thus
is made to ascend the tubes last acted on by the combustion gases to the steam and
water drum S where it joins in the general circulation. The outer tubes A thus
supplied with the feed water practically operate as a feed water heater, utilising
much of the heat still remaining in the combustion gases before they pass to the
chimney.
Having now particularly described and ascertained the nature of this invention
and in what manner the same is to be performed, I declare that what I claim is:-
A water tube boiler having some of the tubes or rows of tubes which
en land.

page_text: acted on by the combustion gases opening at their one end into a compartment
supplied with the feed water, substantially as and for the purposes set forth.
Dated this 23rd day of February 1898.
ABEL & IMRAY,
Agents for the Applicant.