Improvements in Condensing Apparatus for Steam and other Vapours.
Year: 1890

page_text: Date of Application, 12th Mar., 1890
Complete Specification Left, 11th Dec., 1890-Accepted, 7th Feb., 1891
T
PROVISIONAL SPECIFICATION.
Improvements in Condensing Apparatus for Steam and other
Vapours.
1, JULIUS SCHWAGER, of No. 7, Luckenwalder Strasse, Berlin, do hereby
declare the nature of this invention to be as follows:-
In condensing apparatus in which water or other liquid injection is employed for
condensing, and in which an air pump exhausts both the water or other liquid and
the uncondensed vapour or air, it has been customary to assume that this could
only be done with a parallel flow of the liquid and vapour through the condensing
'apparatus and not with an arrangement of reversed currents of, for instance, water
and steam:
My present invention consists in a construction of condensing apparatus in which
the currents or vapour and the condensing liquid are made to flow in contrary
directions, the air pump being made to exhaust both the liquid of condensation, the
condensing liquid. and the uncondensed vapour or air.
For this purpose I arrange a closed upright vessel having a number of central
helically arranged perforated or unperforated plates on to the uppermost of which
the condensing liquid is made to flow, so as to descend equally distributed from
plate to plate, or in a shower through the plates, or both, to the bottom where a
suitable liquid seal or trap is formed, communicating at the outer end with the air
and liquid pump. This pump is at the same time put in communication by a pipe
with the top of the condensing chamber and the steam or vapour to be condensed is
made to enter the chamber through a pipe at bottom. The steam being prevented
by the before mentioned liquid seal or trap from passing down directly into the
pump, it is caused to rise in the helical passage between 'the plates, in the contrary
direction to, and through the descending condensing liquid, to the top of the
chamber, by the exhaust produced by the pump at that point, and becoming thereby
effectually condensed, the liquid of condensation flows down together with the
condensing liquid while the uncondensed vapour is drawn off by the pump.
The exhaust produced in the condenser by this action will be maintained constant
if the pump be made to draw off from the upper part of the condenser a volume of
uncondensed gases equal to that of the steam or vapour entering at the lower end
in a given time.
With this condenser the uncondensed gases are drawn off at the coolest part of
the, condenser, where they are most dense, in the same way as in any other
reversed current condenser acting with a dry air pump, and consequently the
useful effect is the same as with these. This effect may be increased, if the pipe'
connecting the water seal or trap of the condenser with the pump is made of any
considerable vertical length. In that case, the pipe conducting off the "uncondensed
vapour can be made to enter a space in the water pipe surrounding an ejector
nozzle provided therein, the exhaust action produced by the energy of the water
descending through such nozzle at a speed due to the height of the fall; will
accelerate the flow of the vapours and act as a supplemental pump; supplying the
suction of the ordinary wet air-pump.
The liquid seat or trap may either be formed by a bend in the discharge pipe, or
by an inverted cup placed over the inner end of such pipe and dipping into a body
of liquid retained round the end of the pipe in the condenser, or in a space connected.
therewith.
Instead of causing the condensing liquid to flow down over a helically arranged
set of plates, any other known arrangenient may be employed whereby the liquid is;
made to form cataracts or to descend 'in a shower through a circuitous path provided

page_text: for the steam or vapour, or the liquid may be made to enter the condenser in a
finely divided spray which is allowed to descend freely while the steam passes up
through and in contact with it.
I have found however by experiment, that the first described construction with
helically arranged plates has the advantage of affording a higher degree of efficacy
with a less amount of resistance than the other arrangements, and I therefore
prefer to employ it.
The different means employed for distributing the liquid will have different.
effects-in-the condensing process -in-general, but the above described method of
causing the vapours to be condensed and the condensing liquids to pass in
contrary direction through the condenser, in combination with the use of a wet
air pump is of special influence in respect to the useful effect of the condenser.
Dated this 12th day of March 1890.
This invention has for its object to enable counter-currents to be employed in
condensers in combination with a wet air pump; that is to say an air pump that
draws both air and water or with separate-air-and water-pumps, and also to reduce
the resistances arising in such condensers whether operating with a dry or a wet air
pump.
These resistances are mainly caused by constructing, within the condenser,
pans from which the condensing water overflows in cascades through which the
rising vapours or gases can. only penetrate under increase of pressure and con-
séquent rise of temperature.
Although by an improved construction employed by me, with cataract discs and
rings with escape openings, this disadvantage was to some extent obviated, yet the
evil remained, that the condensing liquid and the vapour were subject to sudden
changes of direction of motion.
On the accompanying drawing are shewn in vertical section several arrangements
of counter-current condensers constructed according to my invention;
Fig. 1 shews an arrangement in which the exhaust is produced by a dry air pump
and
Fig. 2 shews an arrangement with wet air pump, both these constructions having
helically arranged plates, like a winding staircase, for effecting the distribution of
the condensing liquid.
Figs. 3 and 4 on the other hand shew constructions with wet air pump while the
distribution of the condensing liquid is effected in Fig. 3 by annular discs and in
Fig. 4 by spraying apparatus.
In the condenser at Fig. 1 the steam enters at a at the lower end, in order to rise
through the helical spaces b¹ b2 63 b to the upper end d.
The steam will, during such, passage be mostly condensed by the condensing
liquid entering at. and trickling down over the helical steps formed by the
sectors S, S. S. .*S. The condensing liquid is by this means forced to partake
alternately of a horizontal retarded motion and of a vertical accelerated motion, and
the steam that is not condensed by the water is drawn off from the top through a
pipe e leading to an air pump, not shewn on the drawing. The condenser liquid
and the condensing liquid flow off together through a pipe r, the lower end of which

page_text: opens into a tank A having an overflow opening A', the opening of the pipe being
situated below, the said opening so as to form a liquid seal.
The steam entering the condenser at bottom finds a free upward passage through
the helical spaces formed between the helically-arranged step-like sectors. In thus
flowing in the contrary direction in contact with the vertically and horizontally,
descending liquid, the steam will be mostly condensed by the latter and the
remainder of the gases will pass in contact with the cooling surfaces of different
temperature until they eventually pass in contact with the entering condensing
liquid in the condition of greatest density and are then drawn off by the air pump.
While thus ascending, the vapours or gases only have to overcome the
resistance due to the friction against the surfaces with which they come in contact.
there being no penetration through layers of liquid, and there is only a gradual
and uniform change of direction of motion due to the helical form of the passage;
consequently the sum of all resistance is a minimum, being in reality less than the
pressure due to a mercury column of 5 "/
If to this counter current condenser were applied, in place of the discharge tube
of 10.3 m. height, a wet air pump, the latter would exhaust simultaneously both
steam and water. This is the cause of the erroneous assumption that with a wet
air pump only condensers with parallel currents could be employed.
In the arrangement shewn at Fig. 2 the condensing liquid is introduced through
pipe at top into the condenser and flows downwards in a finely divided form over
and through the sectors s n, forming at to a water seal and being drawn off through
the pipe by the wet air pump P. The latter is connected at i by the pipe e
directly with the upper part d of the condenser.
The steam to be condensed is introduced at bottom through the pipe a, into the
condenser; there it finds the nearest way to the wet air pump closed at w by the
liquid seal or trap formed by the bell g and mouthpiece n, but on the other hand it
finds a free passage in an upward direction to the upper part d of the condenser.
which is subject to the suction of the pump P through pipe e. In consequence of
the reduced pressure thus produced in the top of the condenser the steam and gases
tend to flow toward such upper part; on their passage they meet the descending;
condensing liquid, and by the resulting cooling action to which they are subjected
the steam is condensed to water and precipitated on to the condensing liquid.
The decrease of volume and pressure produced by the condensation of the steam"
will be maintained constant if the wet air pump draws off through the pipe e as
large a volume of gases in a given time as that of the steam entering through a
during the same time.
With the described arrangement of the pipe e the wet air pump draws the gases
off from the top of the condenser: just the same as with every dry condenser.
consequently at a point where the gases are most cooled and are in the condition of
relatively greatest density.
The effect of this counter current condensation with wet air pump is therefore
the same as with the condensation with dry air pump.
This effect will be increased if the descending pipe r can be of some length:
the water descending through the ejector i at a velocity in proportion to the fall of
the pipe r'. will then exercise a sucking action on the gases descending through the
pipe c. and the suction of the pump' P will be correspondingly increased.
The ejector then has the effect of a pump suction chamber; it discharges into a
partially exhausted space.
Instead of distributing the condensing liquid into a thin layer by means of
helically arranged steps or plates, it can be made to flow with sudden changes of
direction over discs & s¹ Fig. 3. or annular surfaces or pans placed in alternating
positions..
Also. a spraying apparatus Z can be employed as at Fig. 4.
The bell-shaped trap may be replaced by the siphon trap c¹ and the pipe e
can he led down externally, and open into a chamber surrounding an ejector nozzle
on the water discharge pipe leading to the air pump P.

page_text: As above described, the steam entering the condenser at bottom at a, finds the
direct way to the air pump closed by the siphon trap w', but finds a free passage
upward through the condenser.
.. With the arrangement of helical sector plates shown at Fig. 2, the action of the
condenser is precisely the same as described with reference to Fig. 1 when the
resistance to the passage of the gases through the liquid seal is greater than
the total resistance of the ascending current, which, with my arrangement, do not
amount to a 5 m mercury column. The gases are however drawn off from the
condenser through the piper by the wet air pump in the same condition as in the
case of the arrangement at Fig. 1 with dry air pump. It is only necessary to insure
that the duration and extent of surface of the contact of the vapour with the
condensed liquid in the recipient of the pump shall be as small as possible.
By the counter-currents in the condenser the consumption of condensing liquid is
reduced to one half and more, consequently the gases or vapours passing from the
condensing water would only load the pump to half and even less extent than in
the other case. The pump consequently gives, with my counter current arrange-
ment, a correspondingly greater effect, even when the gases unite again in the
recipient.
This effect is greatest with my construction with helical sector plates, but it is
also considerably greater than with parallel current condensers when, as shewn in
Figs. 3 and 4, other arrangements for controlling-the-flow of the water and steam
are employed The essential feature for carrying out the counter current system.
in the condenser, with wet air pump is the drawing off of the condensed liquid and
a liquid seal from the lower part of the condenser and the simultaneous drawing off
of the gases from the upper part of the condenser by the wet-air pump.
-It is therefore possible to employ the counter current system in the condenser
with the wet air pump without the helical sector plates but I have found that the
best effect is obtained with the latter.
Having now particularly described and ascertained the nature of this invention
and in what manner the same is to be performed, I declare that what I claim is
1. In counter current condensing apparatus, the use of a helical arrangement of
sector plates forming a winding staircase the helical passage of which is open for
the vapour to rise through and for the liquid to flow down from step to step.
substantially as described.
2. ID counter current condensing apparatus, a liquid scal or trap communicating
at one end with the lower part of the condenser and at the other end with a pump.
the upper end of the condenser being made to communicate with an air pump,
substantially as described.
3. In counter current condensing apparatus, the combination with the condensing
vessel of a wet air pump. communicating with the top of the condenser by an air
suction pipe and with the bottom of the condenser by a liquid suction pipe having
a liquid seal or trap, substantially as described.
4. In counter current condensing apparatus a condensing vessel having helically
arranged sector plates down which the condensing liquid is made to flow while the
steam or vapour to be condensed is made to ascend in the helical passage between
the sector plates, in combination with a wet air pump connected by an air suction
pipe with the upper part of the condensing vessel and by a liquid suction pipe
having a water seal or trap, with the lower end of the condenser, substantially as
described.
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