Improved Method of and Apparatus for Distilling Sea Water and other Liquids.
Year: 1889

page_text: Date of Application, 14th June, 1889-Accepted, 20th July, 1889
COMPLETE SPECIFICATION.
Improved Method of and Apparatus for Distilling Sea Water and
other Liquids.
I, GEORGE WILLIAM HOVGAARD, of No. 24, St. Anna Plads, Copenhagen,
Denmark, Lieutenant in the Royal Danish Navy, 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:—
This invention has reference to the mode of distilling liquids, whether salt water or
any other liquid.
Instead of condensing the vapours at low pressures and low temperatures in a
condenser where the latent heat is thrown away in the water of circulation, I condense
the vapours at high pressures and high temperatures in a condenser, which is
surrounded by the evaporating liquid, so that the latent heat is given off to that same
liquid.
In order to attain a higher pressure and temperature in the condenser than the
pressure and temperature of the evaporating liquid, the vapours are forced into the
condenser by means of a compressor.
The compressor may be a reciprocating single or double acting pump or a
centrifugal pump or any other suitable mechanical contrivance, which is capable of
compressing vapours.
It may be driven by hand, steam or any other power.
In any case steam must in some way be added to the evaporating liquid to make up
for losses due to radiation, leakage and excess of temperature of distilled liquid over
that of the liquid used for feeding the evaporator.
If the compressor is driven by steam power, heat may conveniently be supplied by
means of the exhaust steam.
The
In order that my invention may be more casily understood and readily carried into
effect I will proceed to describe it with reference to the accompanying drawing..
The drawing shews as an example a distilling apparatus for salt water.
necessary appendages viz. the feed pump, cooling apparatus and filter have been
omitted for the sake of clearness.
Figure 1 is a vertical elevation shewing the evaporator in section and the steam
engine aud.compressor in outside view.
Figure 2 shows a plan section of the evaporator on line L M Figure 1.
In Figure 1, a is the steam cylinder which drives the steam compressor b. The
latter is a reciprocating, double acting pump, which draws the steam from the
evaporator c by the pipe N and after compressing it, drives it into the annular
condenser d by the pipe M.
The exhaust steam from the cylinder is led to the central condenser c.
Both condensers are cylindrical and multitubular the annular condenser being
placed concentrically outside the condenser e.
A perforated screen of is placed immediately above the level of the evaporating sea
water to check ebullition and to prevent any salt water from being carried over in the
condenser by priming.
The steam which is forced into the condenser will here be at a higher pressure
and therefore a higher temperature than the water surrounding the condenser, the
consequence of which is, that heat will pass through the shell of the condenser to the
boiling water in the evaporator and the steam will condense, giving off its Intent heat
to the water in the evaporator, from which that same heat was originally taken. In
this way the fresh water is produced in the annular condenser d.
Only a small amount of additional heat is required in order to make up for losses
due to radiation and other causes so that most of the heat added by the condensation

page_text: of the exhaust steam will be superfluous and will necessitate a brisk feeding with cold
sea water as well as a continuous blow-out through the brine-cock.
Thus a powerful circulation is kept up in the sea water, the density of which will
remain low, deposition of scale will be made impossible, and priming prevented.
The feed pump is to be driven off the same engine, which drives the compressor.
The feed water enters the evaporator by the pipe g.
The brine water blows out automatically through a valve at h, which may or may
not be loaded. The rate at which the blowing out takes place is dependent on the
rate at which steam is developed in the evaporator. The outlet from the condensers d
and e is through the loaded valves and respectively. The difference in load upon
the valves and i determines the difference in temperature between the evaporating
and the condensing fluid..
From the valve i the gained fresh water will pass through a cooling apparatus and
thence through a filter. The greasy boiler steam water which is formed in the
condenser e is led off by way of the valve k to the hotwell or feed water tank and used
for feeding the boiler.
I am aware of Normandy's Double Distilling Condenser in which the boiler steam
is condensed in a vessel surrounded by the sea-water, but according to my invention
the boiler steam is first made to perform work in compressing the secondary steam
and that the latent heat of the secondary steam, instead of being thrown away in the
water of circulation is here used for evaporating the sea water.
The advantages of this apparatus are, greater economy, no deposition of scale and no
priming.
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:
1. The utilization of the latent heat, given off by the distilled vapours, for
evaporating the liquid to be distilled by compressing the distilled vapours into a vessel
surrounded by the evaporating liquid and condensing said vapors in the said vessel.
2. The construction of distilling apparatus substantially as described and shewn.
Dated this 14th day of Lune 1000
JENSEN & SON,
77, Chancery Lane, London, W.C., Patent Agents.