Sur′face-con-dens′er.
1. (
Steam-engine.) A chamber or congeries of pipes in which steam from the cylinder is condensed.
Invented by
Napier.
It generally consists of a large number of brass tubes about 1/2 inch in diameter, united at their ends by means of a pair of flat, steam-tight vessels, or of two sets of radiating tubes.
This set of tubes is inclosed in a casing through which a sufficient quantity of cold water is driven.
The steam, being led by the exhaust-pipe to one end of the set of tubes, is condensed as it passes through them, and arrives in a condensed state at the other end of the apparatus, whence it is pumped away by the airpump.
The
surface-condenser was designed especially for marine engines, to avoid the mixing of the cold salt-water with the water of the condensed steam, which takes place by the use of the injection-condenser.
usual in land engines.
With marine engines, the cold-water cistern is supplied from the sea, and the constant addition of salt-water in the form of injection, which eventually passes from the hot-well to the boiler, causes the accumulation of salt in the boiler, which is got rid of by occasional
blowing-out or by a pump.
See brine-pump.
Brunel's surface-condenser was patented in
England in 1822, and consists of clusters of pipes communicating with steammains and surrounded by the water of the cold-water cistern.
Napier's condenser was a casing around the engine-room, around which the sea-water flowed, entering before and passing out abaft.
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Church's condenser. |
Fig. 6075 is an instance of a surface-condenser for the injection-water of a condensing steam-engine, and may be termed a combined
injection and
surface condenser, the surfacerefrigera-tion being applied to the fresh water, which is injected into the condenser to condense the steam.
As has been stated, the cold-water cistern is the usual source of supply for the jet of cold water which is injected as a spray into the condenser.
This cistern is supplied from the sources at hand on land, and on our rivers and lakes it is furnished with fresh water, and at sea its contents are salt water.
When the latter is used as injection-water, salt gradually accumulates in the boiler, and on reaching a certain degree of saturation must be removed by “blowing out.”
(See Sali-Nometer.) This condenser aims to keep the contents of the boiler fresh by returning the condensed fresh water to the boiler unmixed with salt water: the latter only being used to cool the condensed water, so that it may be used for the purpose of an injection-spray.
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The
refrigeratory consists of three compartments, the upper one being connected with the lower one by means of a number of small pipes which traverse a cistern, through which a stream of cold sea-water constantly flows.
At the starting of the engine, the chambers being full of fresh water, upon the admission of steam into the condenser by the pipe, the injection-cock is opened, and the injection-water is distributed in a shower amidst the steam by the rose; the condensed and injection pass together through the foot valve-way into the chamber beneath the airpump, by whose bucket they are lifted and discharged by another valve-way into the upper chamber, to be again cooled in descending through the pipes which are surrounded by the cold sea-water in the cistern.
Here the temperature is again reduced, so that the water becomes again effective in an injection-spray.
Hall's condenser (
English) consists of a cast-iron vessel
f g h divided into three compartments by two horizontal tube-plates.
Into these plates are secured the ends of a vast number of copper tubes
e of small diameter, which form a communication between the upper chamber
f and the lower chamber
h. Through the middle compartment
g a stream of cold sea-water is maintained by means of a cold-water pump
q and the passages
r s t, of which the former is the cold-water induction-pipe, and the other two are respectively the induction and eduction ports by which the water enters and leaves the compartment
g, from whence it is discharged into the sea.
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Surface-condenser. |
The upper chamber
f communicates with the eduction steam passage from the cylinder
a and valve-chamber
d; and the lower chamber
h communicates by the foot valve-way
k with the well of the air-pump
l.
The steam from the eduction-pipe, entering the upper chamber
f, is instantly dispersed through the condensingtubes
e, which are surrounded by cold sea-water, and is thereby brought into a liquid condition, and falls in a shower into the lower compartment
h, from whence it is drawn, together with the air and uncondensed vapor, by the air-pump
l, which delivers the said fluids into the hot-well, which is closed at top, so that the upper part constitutes an air-vessel, and the elasticity of the compressed air forces the water into the boiler through the pipe
p, which proceeds from the lower part of the hot-well to the feed-valves or cocks on the face of the boiler.
On the top of the hot-well is placed a
snift-valve
n, actuated by a float
o to maintain the water in the hot-well at a certain hight, so as to prevent air from entering the boiler along with the water.
If the air accumulate at the upper part of the hot-well and the water sink below a certain level, the float descends and opens the valve, when a portion of air escapes and restores the desired condition.
The whole of the steam is condensed and the water returned to the boiler, but, to compensate for loss at the safety-valve and leakage, a still is inserted in the top of the boiler, and connected by a pipe and cock with the upper chamber
f of the condenser.
This still is charged with seawater, and when the water in the boiler is too low, the cock is opened, and, a communication being thus established with the condenser, a partial vacuum is formed in the still.
This causes the water to boil rapidly at a much lower temperature than it would otherwise, and the steam, rushing into the condenser, is condensed along with the steam from the cylinder.
The additional water thus obtained is delivered to the boiler by the action of the air-pump.
See still.
a is the steam-cylinder.
b, the steam-pipe from the boiler.
c, a belt or channel surrounding the cylinder and conveying the steam to the slide-valve chest
d.
e, the tubes of the middle chamber
g of the condenser.
f, the upper chamber of the condenser, communicating with eduction steam-port.
g, the middle chamber, containing cold sea-water and traversed by the tubes
e.
h, the lower chamber of the condenser, collecting the water dropping from the tubes.
k, the foot-valve.
l, the air-pump.
m, the hot-well.
n, the snift-valve.
o, the float operating the snift-valve.
p, the feed-pipe leading to the boiler.
q, the cold-water pipe, placed between the valve-chest and the condenser.
r, the cold sea-water supply-pipe.
s, the apertures in the wall of the chamber
g by which the cold water enters.
t, outlet passages by which the water in chamber
g is returned to the sea.
u, the throttle-valve.
w, the blow-through valve.
x, a distributing plate in the upper chamber of the condenser.
Fig. 6077 shows a form in which the steam and the water follow sinuous courses flowing in opposite directions.
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Condenser. |
In
Fig. 6078, a partition
C′ is placed in the chamber in which the cooling water is received, for the purpose of compelling
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water to pass the tubes of the lower or cooling section of the condenser, and return it through the upper or condensing series of tubes; the object being to more thoroughly cool the condensed water than could be done if the cooling water entered both the condensing and cooling tubes at the same time.
The induction and eduction nozzle for the steam and water and the division plates are arranged at the same end of the condenser, whereby the steam and water are each made to traverse the entire length of the instrument in opposite directions before being discharged therefrom.
2. A steam-heated apparatus consisting of pipes or chambers over which a solution is conducted in order that its watery particles may be driven off. Such is the Degrand (Derosne) condenser.
(See condenser.) Such also is the evaporating cone of
Belgium.
(See evaporator.) Useful hints on construction may be gathered from liquid-cooler, beer-cooler; apparatuses which differ from these surface-condensers merely in the fact that a refrigerating liquid instead of steam occupies the hollow trunk.
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Surface-gage. |
