Improvements connected with Feed-water Apparatus for Steam Boilers and Feed-heating Economisers and for Preventing Corrosion.
Year: 1898

page_text: Date of Application, 31st May, 1898
Complete Specification Left, 25th Feb., 1899-Accepted, 25th Mar., 1899
PROVISIONAL SPECIFICATION.
Improvements connected with Feed-water Apparatus for Steam
Boilers and Feed-heating Economisers and for Preventing
Corrosion.
I, JAMES WEIR, of Holm Foundry, Cathcart, in the County of Renfrew, North
Britain, Engineer, do hereby declare the nature of this invention to be as follows,
that is to say:--
My said invention has principally for its object to prevent corrosion in steam
boilers and economisers, more especially those of the tubulous type working at
high pressures; and this may be accomplished with a great measure of economy,
when exhaust steam from auxiliary engines or steam from the receivers of the
main engines is employed in the process. My improved apparatus provides for
the removal from the feed water of air and corrosive gases by subjecting it to a
pressure less than that of the atmosphere to effect a complete separation, the
decrease of pressure necessary for this being that at which the feed water will
boil in the air-separating vessel. The apparatus is also arranged to ensure the
satisfactory working of the feed pumps by preventing fluctuation of the pressure
in the vessel or tank from which the feed pump draws the feed water after treat-
ment. The position vertically of this vessel or tank in relation to the feed pumps
will depend on the temperature of the water.
According to one modification, the improved combination or apparatus consists
of (1) an air-separating tank or vessel, and (2) a receiver tank or vessel from which
the feed pumps take their supply. The air-separating tank is a closed vessel, and
is fitted with an inlet for the water placed near the top, and an outlet at the
bottom. A connection is made from the top of this vessel to the surface con-
denser, or a special air pump may be used to draw off the air. The receiving tank
is a vessel open to the atmosphere, and is provided with an inlet connection led
from the outlet of the air-separating vessel, and an outlet connection leading to
the feed pumps. The position vertically of the above mentioned vessels with
relation to each other will depend on the temperature of the feed water under
treatment and to what extent it has been heated before entering into the air-
separating vessel. For example, when the water is comparatively cool, say under
150 degrees Fahrenheit, the receiver tank may be on a level with or slightly under
the feed pumps, and the air separating vessel may be 35 feet above it. For the
treatment of water up to the boiling point the two vessels may be placed as nearly
as possible at the same level, provided the water will run out of the one into the
other. When arranged to deal with hot water, a non-return valve must be fitted
in the connection between the vessels. When the height of the separating vessel.
in relation to the hotwell or other vessel from which the feed supply is obtained is
not sufficient to prevent the air being forced into it by the atmospheric pressure,
a loaded valve or its equivalent must be fitted to the water inlet connection of
the separating vessel. The feed water may be heated before treatment by any of

page_text: valve, N, while the water of condensation passes off by a drain pipe, P. The
feed water enters the heater by an inlet pipe, Q, and after passing over the external
surfaces of the heating tubes is discharged into the air-separating tank, A, by the
pipe, R, which connects the heater, M, with the inlet, C, of the tank, A. Any
other usual method of heating the feed water may however be adopted, or it may
be heated in the air-separating tank.
In another modification of my improvements shown in Figure, 2, the air-
separating vessel, A, instead of being made separate is made to form part of the
feed-water heater, M, the feed water being arranged to pass through the heating
tubes, S, so as to enter the air separating vessel or chamber, A. The heating
steam enters the heater by a valve, N, and acts on the external surfaces of the
tubes, and another valve, T, is also provided for the discharge of surplus steam
from the heater.
For
In both modifications of my improved apparatus as herein before described, the
vertical distance of the air separating tank or chamber, A, from the receiving
tank, B, will depend on the temperature of the feed water under treatment, and
to what extent it has been heated before entering the air separating vessel.
example when the water is comparatively cool say under 150 degrees Fahrenheit,
the receiving tank, B, may be on a level with, or slightly under, the feed pumps,
and the air-separating vessel, A, may be about 35 feet above it. For the treat-
ment of water up to the boiling point the two vessels, A, and B, may be placed
as nearly as possible at the sameve, provided the water will run out of, A,
into, B. When arranged to deal with hot water a non-return valve, V, as shown in
Figure, 2, is fitted to the inlet, J, of the receiving tank, B. When the height of
the air-separating vessel, A, in relation to the hotwell or other vessel from which
the feed supply is obtained is not sufficient to prevent the air being forced into
it by the atmospheric pressure, a loaded valve or its equivalent must be fitted to
the water inlet, C, of the air-separating vessel.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:-
Improvements connected with feed water apparatus, in which a closed vessel
or chamber made separate, or forming part of a feed-water heater, and kept at
a low pressure or vacuum by connection with a surface condenser or air-pump,
is combined with a receiving tank or vessel from which the boiler feed pump takes
its supply, the said vessel being placed at a lower level and open to the atmosphere,
the vessels being provided with pipe and valve connections, and the parts being
arranged and operating substantially as and for the purposes hereinbefore described
with reference to the accompanying drawings.
Dated this Twenty-fourth day of February 1899.
EDMUND HUNT,
Applicant's Agent.