Year: 1894

page_text: Date of Application, 9th Nov., 1894-Accepted, 12th Jan., 1895
Fig. 4 is a horizontal section on the line Y Y of Fig. 2.
Fig. 5 illustrates the meeting of water currents with the successive turns of a
conical coil.
Fig. 6 is a detail view of the salt water inlet valve.
Similar letters of reference indicate like parts.
1 is the evaporating tank of suitable plate metal, cylindrical in form and
provided with heads, 2 and 3, braced by the tie-rod 4. 5 is an upper annular
steam-chamber, which may be circular in cross-section. 6 is the lower steam
chamber, also annular, but preferably made rectangular in cross-section, and of
greater sectional area than the chamber 6, so as to afford ample space for the
condensed steam readily to separate itself. Between the chambers 5 and 6 extend
the evaporator coils 7. Of these coils any desired number may be provided. They
are preferably arranged as shown in Fig. 4, so that while their extremities are
connected to the median line of the annular chambers the coil bodies protrude
alternately on opposite sides of that line-or, in other words, are staggered. In
this way I am enabled to pack a greater number of coils in smaller space, and at
the same time to concentrate better their heating effect.
Each coil is preferably made in the form of a spiral-the diameter of the spiral
gradually augmenting from the bottom of the coil to the top. This is a feature of
especial importance. I have found that where such a coil is made of uniform
diameter, so that a vertical line would touch the outer surface of every turn, a
cylindrical film of steam forms around the coil. This prevents the water in the
tank 1 from coming in contact with the surface of the coil, and therefore the
evaporative effect of the heated surface of the latter is greatly retarded, for
the upward water current simply runs along this steam cushion and the circulation
does not take place within the interior of the coil.
On the other hand, if the coil is made with its diameter gradually increasing
upward, then the water current, moving vertically, meets the turns of the coil
successively, as shown in Fig. 5, where the current represented by arrow 9 strikes
the turn 10, while the current represented by arrow 11 strikes the turn 12. In
this way, instead of the upwardly-circulating water merely flowing along the outer
surfaces of all the turns, the under surface of every turn is met by it, and, as a
ID011

page_text: consequence, there is a free circulation around every turn and through the interior
of the coil. The steam which forms on the coil is thus wiped off by the ascending
currents which make contact with the whole of the heating surface afforded.
The coil tubes are preferably elliptical in cross-section. By reason of this shape
the tube in expanding causes whatever scale may be deposited on it to crack, and
finally to fall off.
I have designed the apparatus here shown more particularly for use in
evaporating salt water on board ship in order to produce a fresh water supply.
I will describe its operation with reference to that particular use, and with
reference to the construction particularly suited thereto, which is exhibited in the
drawings.
The salt water to be evaporated is introduced through the valve 14, which is
shown in the detail view-Figure 6. The inlet pipe is here curved downward
inside of the tank, so as to prevent its becoming clogged. The salt water then
fills the tank about up to the level indicated in Fig. 2. and flows over the edge of the
funnel 15, which is secured upon the outlet pipe 16; said pipe passing through
the wall of the tank, and being provided with a suitable valve, 17. In this water
the coils are immersed. The vapor then passes upward, meeting on its way the
deflecting disk 18, which tends to throw back any unvaporized water-particles ;
and, passing through the opening 19 in said disk goes to the escape outlet 20,
which communicates with the upper part of the tank, as shown in Figs. 1 and 3,
and is provided with a suitable valve, 21. The live steam enters by the pipe 22,
which is provided with a valve, 23. The pipe 22 communicates directly with the
upper steam-chamber 5, so that the steam, circulating around the chamber 5,
passes thence into the coil 7, and then to the lower chamber 6. Meanwhile, it
has become cooled by radiation, and becomes, in part, condensed in the chamber 6.
The spent steam and condensed water thence flow from the chamber 6 out through
the pipe 24, which has a suitable valve, 25. It will be noticed that by this
arrangement the vapor which is given off from the surface of the water meets the
hottest part of the evaporating coils, while, on the other hand, after the steam has
become expanded in the coils, it goes into the large chamber 6, which exposes a
materially increased area to the heating effect of the now partly cooled steam,
thus utilizing that effect to the best advantage, while at the same time, as already
pointed out, affording ample space for the collection of the condensed water.
It will be apparent from the foregoing that the operation of this apparatus is
continuous that is, there may be a constant flow of salt water to be evaporated
through the tank from the valves 14 to 17, constant flow of live steam through the
evaporating coils and chambers between valves 23 and 25, and a constant outflow
of vapor from the outlet pipe 20, controlled by valve 21, to the condenser, if
desired.
In Fig. 1 I indicate at 26 a safety valve, which communicates with the lower
part of the tank, and the pipe of which, by means of the tube 27, is connected to
the pressure gauge 28. A suitable glass water-gauge, 29, is also provided on the
outside of the tank. The manholes 30 and 31 afford access to the interior of the
tank, and the faucet 32 serves for drawing off any material which may accumulate
at the bottom.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, as communicated to
me by my foreign correspondent I declare that what I claim is ;
1. An evaporating apparatus substantially as hereinbefore set forth, having a
receptacle for the material to be acted upon, two chambers disposed horizontally
therein one above the other, and series of tapering coils interposed between and
communicating with said chambers.
2. An evaporating apparatus substantially as hereinbefore set forth, having a
receptacle for the material to be acted upon, two chambers therein, one of larger
cross-sectional area than the other, and a tapering coil extending between said

page_text: chambers; the part of said coil of largest diameter being connected to the
chamber of least cross-sectional area, and vice versa.
3. An evaporating apparatus substantially as hereinbefore set forth, having a
receptacle for the material to be acted upon, two chambers disposed one above
the other, and a series of staggered tapering coils interposed between said
chambers.
4. In an apparatus substantially as hereinbefore described, a receptacle for
the material to be acted upon, chambers and tapering coils of tubing of
elliptical cross-section extending vertically between said chambers.
Dated this 6th day of November 1894.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.