IMPROVED APPARATUS FOR OBTAINING FRESH WATER FROM SALT WATER
Year: 1884

page_text: I, JAMES WEIR, of 49 Jamaica Street, Glasgow, in the County of Lanark,
North Britain, Engineer, do hereby declare the nature of my said invention for
"IMPROVED APPARATUS FOR OBTAINING FRESH WATER FROM SALT WATER
33 to be
as follows:-
My said Invention has for its object to obtain fresh water from salt water in an
economical manner and by improved apparatus specially designed to be used on
board steamships or where steam is raised for motive-power or other purposes.
And in carrying out my Invention instead of using a separate boiler of the
ordinary kind to raise steam from the salt water in order to supply the fresh water
by its condensation, I employ steam which has worked in the engines of the ship,
or which is part of the steam raised in a boiler for other purposes; and I cause
such steam to pass through a worm or equivalent heat-exchanging apparatus in a
vessel supplied with water directly from the sea. This salt water is evaporated
by heat from the steam passing through the worm, and it is the steam due to such
evaporation which is condensed to form the fresh water. For condensing the
steain evaporated from the salt water in the first vessel there is provided a second
vessel with a worm or equivalent heat-exchanging apparatus, the first vessel being
closed and having a pipe connecting the top of it to the heat-exchanging apparatus
of the second vessel. The second vessel is also closed and a pipe is led from the
top of it to the condenser of the main engines, in consequence of which arrange-
ment the cooling water in the second vessel will not require frequent renewal, and
the heat communicated to it will be utilised in causing evaporation under the
reduced condenser pressure the resulting vapor passing to the condenser and
serving to compensate for leakage of the water in the boilers of the main engines
(it being of course understood that the boilers are worked with fresh water and
that a surface condenser is used). The water condensed in the second vessel passes
off to a storage tank by a pipe extending downwards as far as conveniently

page_text: practicable; and a vessel is provided in connection with such pipe for the accumula-
tion of the air from the salt water, the air being discharged from the vessel
periodically.
With my improved apparatus the steam from which the fresh water is formed is
not contaminated with grease or other impurity which is carried over with the
steam from the engines or other apparatus. The water due to condensation of the
steam passing through the worm of the first vessel may be returned to the hot
well of the engines; and if grease or other impurities become deposited inside of
the worm they may be removed by periodically blowing high-pressure steam
through it.

page_text: COMPLETE SPECIFICATION.
I, JAMES WEIR, of 49 Jamaica Street, Glasgow, in the County of Lanark,
North Britain, do hereby declare the nature of my said invention for "IMPROVED
APPARATUS FOR OBTAINING FRESH WATER FROM SALT WATER "and in what manner
the same is to be performed, to be particularly described and ascertained in and by
the following statement, that is to say :-
My said Invention has for its object to obtain fresh water from salt water in an
economical manner and by improved apparatus specially designed to be used on
board steamships or where steam is raised for motive-power or other purposes.
And in carrying out my Invention instead of using a separate boiler of the
ordinary kind to raise steam from the salt water in order to supply the fresh water
by its condensation I employ steam which has worked in the engines of the ship
or which is part of the steam raised in a boiler for other purposes and I cause
such steam to pass through a worm or equivalent heat-exchanging apparatus in a
vessel supplied with water directly from the sea. This salt water is evaporated
by heat from the steam passing through the worm, and it is the steam due to such
evaporation which is condensed to form the fresh water. For condensing the
steam evaporated from the salt water in the first vessel there is provided a second
vessel with a worm or equivalent heat-exchanging apparatus, the first vessel being
closed and having a pipe connecting the top of it to the heat-exchanging apparatus
of the second vessel. The second vessel is also closed and a pipe is led from the
top of it to the condenser of the main engines, in consequence of which arrange-
ment the cooling water in the second vessel will not require frequent renewal, and
the heat communicated to it will be utilised in causing evaporation under the
reduced condenser pressure the resulting vapor passing to the condenser and
serving to compensate for leakage of the water in the boilers of the main engines
(it being of course understood that the boilers are worked with fresh water and
that a surface condenser is used). The water condensed in the second vessel passes
off to a storage tank by a pipe extending downwards as far as conveniently
practicable, and a vessel is provided in connection with such pipe for the accumula-
tion of the air from the salt water, the air being discharged from the vessel
periodically.
With my improved apparatus the steam from which the fresh water is formed is
not contaminated with grease or other impurity which is carried over with the
steam from the engines or other apparatus. The water due to condensation of the
steam passing through the worm of the first vessel may be returned to the hot
well of the engines; and if grease or other impurities become deposited inside of
the worm they may be removed by periodically blowing high-pressure steam
through it.
Apparatus constructed for carrying out my Invention is shown upon the accom-
panying sheet of explanatory drawings, figure, 1, of these drawings being a vertical
section of what is hereinbefore referred to as the first vessel, figure, 2, being an
elevation of the second vessel, and figure, 3, an elevation of a supplementary
vessel.

page_text: The first vessel, 4, figure, 1, is made of cast iron in the form of a vertical cylinder,
or it may have any other convenient form. The steam used in it may be taken
directly from boilers supplying the main engines or other steam machinery of a
ship, or when the engines are compound the steam may be taken from the first or
other intermediate receiver, or on the other hand high-pressure steam direct from a
boiler may be passed through the first vessel, 4, and subsequently into the first or
other intermediate receiver of the engines. The steam enters the vessel, 4, by
a pipe and stopcock, 5, and proceeds through an internal pipe and worm, 6, to an
outlet stopcock and pipe, 7. Sea water is admitted into the vessel by a three-way
cock, 8, which also serves for discharging it again when it has become considerably
concentrated. The heat of the steam passing through the pipe and worm, 6,
evaporates the sea water, and the steam so produced passes through a stopcock, 9,
at the top of the vessel. The second vessel, 10, figure, 2, is similar to the first, 4,
and the steam formed from the sea water in the first vessel proceeds to the second
by a pipe, 11, which communicates with an internal pipe and worm similar to
those, 6, of the first vessel. Sea water is admitted to the second vessel, 10, to
cool or condense the steam passing through the pipe and worm inside of it, and the
top of the vessel being connected through a stopcock and pipe, 12, with the con-
denser of the main engines the sea water is vaporised to some extent and thereby
kept from becoming much heated, whilst the steam passing to the condenser serves
to supply the main boilers to make up for leakage and waste. The steam
evaporated from the sea water in the first vessel, 4, and cooled or partially con-
densed in the pipe and worm of the second vessel, 10, passes through a stopcock, 13,
and pipe, 14, to a vessel, 15, in which the condensation and refrigeration is com-
pleted the pipe, 14, communicating with a worm inside of the vessel, 15, whilst a
current of sea water is continuously passed through the vessel outside of the pipe
and worm, such current entering by an inlet, 16, and passing off by an outlet, 17.
This vessel, 15, is by preference placed at a level as much lower than that of the
first and second vessels, 4, 10, as is conveniently possible; and its bottom part, 18,
is provided with a filter such as is ordinarily employed in apparatus for distilling
fresh water from salt water. A stopcock, 19, is provided at the bottom for drawing
off the distilled water, and at a higher point a stopcock, 20, is provided for letting
out air. Gauge glasses, 21, are fitted to the vessels, 4, 10, for showing the height
of the water inside of them.
-
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
Apparatus for obtaining fresh water from salt water in which the salt water is
evaporated by the heat of steam raised in a boiler for supplying main engines or
other steam machinery on board ship, such steam being used for the said purpose
either before or after being used or partly used in the main engines or steam
machinery, the said apparatus being arranged and operating substantially as herein-
before described.
Dated this twenty eighth day of May 1885