IMPROVEMENTS IN PROCESSES AND IN FEED-PUMPING AND OTHER APPARATUS · FOR PREVENTING OR DIMINISHING CORROSION IN STEAM BOILERS
Year: 1880

page_text: LETTERS PATENT to George Weir and James Weir, both of Glasgow, in
the County of Lanark, North Britain, Engineers, for an Invention of
"IMPROVEMENTS IN PROCESSES AND IN FEED-PUMPING AND OTHER APPARATUS ·
FOR PREVENTING OR DIMINISHING CORROSION IN STEAM BOILERS, THE
PROVISIONAL SPECIFICATION left by the said George Weir and James
Weir at the Office of the Commissioners of Patents on the 25th June 1880.
GEORGE WEIR and James Weir, both of Glasgow, in the County of Lanark,
North Britain, Engineers. "IMPROVEMENTS IN PROCESSES AND IN FEED-PUMPING
AND OTHER APPARATUS FOR PREVENTING OR DIMINISHING CORROSION IN STEAM
BOILERS, THE PUMPING APPARATUS BEING ALSO APPLICABLE OTHERWISE.'
"
This Invention has principally for its object to prevent or diminish corrosion in
steam boilers, and in carrying it out according to one modification an improved
and special construction is employed, and is also advantageously applicable for
other pumping operations.
The Invention is based on the belief, strengthened by extensive observation and
numerous experiments, that the corrosion occurring in steam boilers is very largely
due to the presence in the water of injurious gases which have a corrosive action
on the metal of the boilers whilst the water is being evaporated. The present
applicants have applied special apparatus for separating air or gases from the feed
water of steam boilers, and in most cases such apparatus has the desired effect; it
is, however, believed that the difficulty may be successfully attacked in a different
way and by means which may in some cases be found more conveniently applicable,
or which may be found advantageously applicable in combination with air
separating apparatus.
When marine or other steam engines are worked with surface condensers it is
in connection with the condenser, air-pump, hot well, and feed pump that the feed
water becomes more or less charged with air or gas, the water taking up the
constituents of the atmosphere unequally, so that of the gases absorbed by it there
is a larger proportion of oxygen-than-in the air, such oxygen becoming the
principal corrosive agent in the boiler. This absorptive action is very much
DC1

page_text: favored by the mode in which the water is ordinarily removed from the condenser
to the boiler, in other words, by the action of the air pump, by exposure in the hot
well, and by the reciprocating or intermittent action of the feed pumps.
By the present Invention the feed water is removed from the bottom of the
condenser by a suitable feed pump instead of the ordinary air pump, the communi-
cation with such feed pump being placed in a relatively low position, and so as
that during the ordinary working of the engine no air or gas (excepting what may
be already in solution in the water) has access to the pump. The pump thus works
with unmixed or "solid" water; but as reciprocating feed pumps which are driven
at a high speed cannot be got to work satisfactorily with such unmixed water on
account of concussive action, and because of the absence of air or gas to give some
elasticity, an improved uniform and continuous action pump is employed and is
hereinafter described.
In addition to the taking of the feed water from the condenser, as described, in a
manner to give it the least possible opportunity for absorbing gases, or in some
cases instead of doing so there is by this Invention presented to the water a gas
or mixture of gases of a non-corrosive nature, and such as by preoccupation to
prevent the absorption of injurious gas, or to dilute and so render innoccuous any
injurious gas that may be absorbed. Various gases may be applied in this way as
anti-corrosive gases, such as hydrogen, obtainable by dissolving a metal in acid; or
nitrogen, obtainable from the atmosphere by removing the oxygen thereof; or
carbonic oxide, obtainable by passing carbonic acid gas through incandescent coke;
Whatever
or carburetted hydrogen, obtainable by well known means from coal.
anti-corrosive gas is employed is led into the condenser, or by a pipe or pipes to
the feed-water pipe, or to a vessel through which the feed water passes. Or the
anti-corrosive gas may be led into the steam pipe or other part through which the
steam passes so as to mix with the steam before the condensation thereof.
In the improved pumping apparatus two toothed wheels gearing together are
employed according to a well known plan, but the heavy unbalanced strains acting
on the shafts of the wheels in arrangements hitherto adopted are very much
diminished by placing the wheels in a rectangular or other box or vessel, the sides
of which the wheels do not touch, and in which there is the same liquid pressure
When the inlet
all round the wheels excepting at a small part of each wheel.
communicates with the outer parts of the wheels the outlet communicates with a
small space beginning at the line of centres or the part where the teeth are in gear,
and extending a short distance thence in the direction in which the teeth move, the
part of this space not bounded by the parts of the wheels being bounded by
partitions separating the inlet from the outlet space. Between the wheels and the
outer casing shells are fixed, but so as not to touch the wheels, and these shells are
made with openings only at the ends of the wheels and concentric with the shafts,
so that the water has to enter these openings to get to the circumferences of the
wheels, and being moved outwards by centrifugal action due to the ends of the
wheels is compelled by the outer parts of the shells to accumulate on the teeth,
which prevents the water from being thrown out of the teeth by centrifugal action,
and allows of the wheels being driven at a comparatively higher velocity.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said George Weir and James Weir in the Great Seal Patent Office on the
23rd December 1880.
GEORGE WEIR and JAMES WEIR, both of Glasgow, in the County of Lanark,
5 North Britain, Engineers. "IMPROVEMENTS IN PROCESSES AND IN FEED-PUMPING
AND OTHER APPARATUS FOR PREVENTING OR DIMINISHING CORROSION IN STEAM
BOILERS, THE PUMPING APPARATUS BEING ALSO APPLICABLE OTHERWISE.'
"
Our said Invention has principally for its object to prevent or diminish corrosion
in steam boilers, and in carrying it out according to one modification an improved
and special construction is employed, and is also advantageously applicable for other
pumping operations.
Our Invention is based on the belief, strengthened by extensive observation and
numerous experiments, that the corrosion occurring in steam boilers is very largely
due to the presence in the water of injurious gases, which have a corrosive action on
the metal of the boilers whilst the water is being evaporated. We have applied
special apparatus for separating air or gases from the feed water of steam boilers,
and in most cases such apparatus has the desired effect. We however believe that
the difficulty may be successfully attacked in a different way and by means which
may in some cases be found more conveniently applicable, or which may be found
advantageously applicable in combination with air separating apparatus.
When marine or other steam engines are worked with surface condensers it is in
connection with the condenser, airpump, hotwell, and feed pumps that the feed water
becomes more or less charged with air or gas, the water taking up the constituents
of the atmosphere unequally, so that of the gases absorbed by it there is a larger
proportion of oxygen than in the air, such oxygen becoming the principal corrosive
agent in the boiler. This absorptive action is very much favored by the mode in
which the water is ordinarily removed from the condenser to the boiler, in other
words, by the action of the airpump, by exposure in the hotwell, and by the
reciprocating or intermittent action of the feed pumps.
By our present Invention the feed water is removed from the bottom of the
condenser by a suitable feed pump instead of the ordinary air pump, the communi-
cation with such feed pump being placed in a relatively low position, and so that
during the ordinary working of the engine no air or gas (excepting what may be
already in solution in the water) has access to the pump. The pump thus works
with unmixed or "solid" water, but as reciprocating feed puinps which are driven
at a high speed cannot be got to work satisfactorily with such unmixed water on
account of concussive action, and because of the absence of air or gas to give some
elasticity, we either employ an improved uniform and continuous action pump
hereinafter described, or we adopt a system of working and apparatus which forms
part of the subject matter of Letters Patent, for which we applied on the 27th day
of October 1880 (No. 4379).
In addition to the taking of the feed water from the condenser, as described, in a
mauner to give it the least possible opportunity for absorbing gases, or in some
cases instead of doing so we by our present Invention present to the water a gas or
mixture of gases of a non-corrosive nature, and such as by preoccupation to prevent
the absorption of injurious gas, or to dilute and so render innoccuous any injurious
gas that may be absorbed. Various gases may be applied in this way as anti-
corrosive gases, such as hydrogen, obtainable by dissolving a metal in acid; or
nitrogen, obtainable from the atmosphere by removing the oxygen thereof; or
carbonic oxide, obtainable by passing carbonic acid gas through incandescent coke;
or carburetted hydrogen, obtainable by well known means from coal or other
carbonaceous matter. Whatever anti-corrosive gas is employed is led into the

page_text: condenser, or by a pipe or pipes to the feed-water pipe, or to a vessel through which
the feed water passes. Or the anti-corrosive gas may be led into the steam pipe or
other part through which the steam passes, so as to mix with the steam before
the condensation thereof.
And in order that our said Invention and the manner of performing the same may 5
be properly understood, we hereunto append two Sheets of explanatory Drawings to
be hereinafter referred to, and representing examples of arrangements and
apparatus to be used in effecting our improvements.
Figures 1 and 2 on Sheet 1 of the accompanying Drawings are a plan and a side
elevation showing (without some details) a set of inverted-cylinder screw propeller
engines as fitted with modifications of our apparatus. Figures 3 and 4 are enlarged
vertical sections of some parts shown in Figure 2. Figure 5 is a vertical section of
apparatus for obtaining anti-corrosive gas, and designed for use on board
ship. Figures 6 and 7, on Sheet 2, are vertical sections as at right angles to each
other of our improved pumping apparatus; and Figures 8 and 9 are also vertical
sections, but as taken at different planes from those of Figures 6 and 7. In these
Drawings the saine reference numerals are used to mark the same or like parts
wherever they are repeated.
In the apparatus shown in Figures 1 to 4 the bottom of the surface condenser 11
communicates by a passage 12 with a chamber 13 below the foot valve 14 of the
airpump 15, and from the chamber 13 a passage 16 for the water descends to the
bottom of a feed pump 17, such passage being provided with a stop valve 18 for
closing the communication when desired. The feed pump 17 is represented as of
the bucket class, having a valve in the piston. A hotwell 19 is applied in the
ordinary way in connection with the upper or delivery end of the air pump 15; and
a second feed pump 20 (but shown as of the plunger class) is applied at the side
of the airpump, being arranged to be worked by the crosshead 21 which also works
the airpump 15 and the other feed pump 17. A vessel 22 is shown, which may be
either a feed heater or an air separator; and there are various connecting pipes
arranged so that the apparatus can be worked in different ways, and so that when
any part requires to be examined or repaired or adjusted, it can be shut off by stop
valves and the working of the engines go on uninterruptedly, the feed water being
passed through other parts. The lower feed pump 17 delivers through a check
valve to a three-way cock 23, from which one pipe 24 leads to the feed heater 22,
and another 25 to the boiler feed pipe 20. The hotwell 19 communicates through
a vessel 27, stop valve 28, and pipe 29 with the pipe 24 proceeding to the feed
heater 22; and in the vessel 27 there is a float 30 provided to prevent the passage
of free air by closing a valve whenever the water in the vessel gets below a certain
level. The float 30 has attached to its bottom a tube 31, which works on a close-
topped tube 32 communicating with the outlet; and the latter tube 32 is formed
with one or more slots which are covered by the float tube 31 when the water gets
too low. The feed heater 22 has a pipe 33 leading from its bottom to the inlet
valve in the valve box of the higher feed pump 20; and a pipe 35, fitted with a
stopcock, also forms a communication with that pump from the bottom of the
hotwell 19, the pump (20) delivering into the boiler feed pipe 26. From the top of
the vessel 22 a small pipe 36 with a stopcock is provided for leading air separated
from the water into the condenser 11. With these arrangements the feed water
may be taken in the ordinary way directly from the hotwell 19 and passed by the
pump 20 into the boiler feed pipe 26; or the water may be led from the hotwell 19
through the float vessel 27 and by the pipe 24 to the feed henter or air separator 22,
and thence through the feed pump 20 to the boiler feed pipe; or again, the water
may be taken directly from the condenser without passing through the air pump 15
and be forced by the feed pump 17 either through the feed heater or air separator 22,
or directly to the boiler feed pipe 26.
When an anti-corrosive gas is to be added to the feed water for the purpose
herein before explained, it may be led into the condenser 11 by a pipe and
stopcock 37, or it may be led by a pipe and stopcock 38 into the inlet of the higher

page_text: feed pump 20, or it may be led into the lower feed pump 17 by an inlet 39. The
apparatus shown in Figure 5, for obtaining the anti-corrosive gas, is designed for
converting a suitable hydrocarbon oil into carburetted hydrogen, and consists of a
casing 40 lined with firebrick to form a furnace, in the top of which there is fitted
an iron retort 41. The oil is supplied to the retort in a gradual manner by means
of a pipe 42 and cup 43, arranged like a lubricator, being fitted with an internal
tube 44, in which a wick is placed. The gas generated is led away by the pipe 45.
One simple mode of introducing an anti-corrosive gaseous mixturo consists in
employing an ordinary paraffin or other oil lamp, and putting the top of the
chimney thereof in communication with the pipe and stopcock 37 leading into
the condenser 11. The gaseous products of combustion consists largely of nitrogen
carried into the condenser in consequence of the low pressure, and have an
opportunity of mixing with the water therein. When an anti-corrosive gas is
employed in the manner proposed by us, and for the purposes hereinbeforo
indicated, it also imparts elasticity to the water, and admits of ordinary feed
pumps being used, and of their being driven at a greater speed than is conveniently
or safely practicablo when the water is "solid" or unmixed with any gas.
In our improved pumping apparatus shown on Sheet 2 of the Drawings, two
toothed wheels 46, 47, gearing together are employed, according to a well known
plan, but the heavy unbalanced strains acting on the shafts 48, 49, of the wheels in
arrangements hitherto adopted are very much diminished by placing the wheels in
a rectangular or other box or vessel 50, the sides of which the wheels 46, 47, do
not touch, and in which there is the same liquid pressure all round the wheels,
excepting at a small part of each wheel. In the modification shown, the inlet 51
communicates with the outer parts of the wheels 46, 47, and the outlet 52 com-
municates with a small space 53, beginning at the line of centres, or the part where
the teeth are in gear, and extending a short distance thence, the part of this space
not bounded by the parts of the wheels being bounded by partitions separating the
inlet from the outlot space. These partitions are formed partly on the piece having
in it the outlet 52, and partly by plates 54, which latter can be accurately adjusted
by means of screws 55 entered from the outside. The lower part of the casing 50
is separated from the space in which the wheels 46, 47, work by a shell 56, access
to the interior of which is obtained by semicircular openings 57 near the centres of
the wheels, and on both faces thereof. This arrangement prevents the water from
being thrown out of the teeth of the wheels by centrifugal action, the frictional and
centrifugal action due to the faces of the wheels causing the water to be forced
towards the circumferential parts and into the teeth of the wheels, and allows of
the wheels being driven at a comparatively higher velocity. The shafts 48, 49, of
the wheels, pass out through stuffing boxes 58 in the casing 50, and are supported
externally in bearings 59, having ample surface. One, 49, of the shafts is extended
to carry a pulley for a driving belt.
Having thus particularly described our said Invention, and the manner of
performing the same, we have to state that we do not restrict ourselves to the
precise details herein described or delineated, but that what we believe to be
novel and original, and claim as the Invention secured to us by and in terms of
the herein before in part recited Letters Patent is,-
1. The preventing or diminishing of corrosive action in steam boilers by
transferring water thereto from the condenser, in a manner to avoid as much as
possible the admixture with such water of air or corrosive gas, and by means of
apparatus arranged and operating substantially as herein before described.
2. The connecting of the outlet from a surface condenser with an airpump and
with a feed pump, the latter being arranged to draw water from the connecting
passage, substantially as and for the purposes herein before described.
3. The supplying of water to a steam boiler from a feed heater or air separator,
in a manner to avoid as much as possible the admixture with such water of air or
corrosive gas, and by means of apparatus arranged and operating substantially as
hereinbefore described.

page_text: 4. The mixing of an anti-corrosive gas or gaseous mixture with feed water, for
the purpose of preventing or diminishing corrosion in steam boilers or for cushioning
the pumps, substantially as hereinbefore described.
5. The improved combination of parts constituting the pump, hereinbefore
described with reference to Figures 6 to 9 of the accompanying Drawings.
In witness whereof, we, the said George Weir and James Weir, have hereunto
set our hands and seals, this Twenty-first day of December, in the year of
our Lord One thousand oight hundred and eighty.
Witness,
EDMUND HUNT,
Patent Agent,
Glasgow.
GEORGE WELK. (L.S.)
JAMES WEIR.
(L.S.)