and chinks against the influx of draughts. Cracks in floors, around
the skirting board, or other parts of a room, may be neatly and
permanently filled by thoroughly soaking newspapers in paste made
of 1 lb. flour, 3 quarts of water, and a tablespoonful of alum,
thoroughly boiled and mixed. The mixture will be about as thick as
putty, and may be forced into the cracks with a case knife. It will
harden like papier-maché. Old windows that do not close tightly may
be remedied by smearing the edge on which they close with putty,
and that of the sash with chalk, and then closing them as firmly as
possible. The putty will fill up the crevices, and the excess pressed
out at the sides may be removed with a knife, whilst the chalk
prevents adhesion to the sash.
A system in very general use is Moore’s patent glass louvre
ventilator, consisting of a number of louvres (or slips of glass),
which can be opened to any angle up to about 45°, thus always
directing the incoming current of air upwards. They are easily
regulated and secured by a cord, which when released allows the
louvres to close practically air-tight. Moore’s circular glass
ventilator, which consists of (usually five) pear-shaped openings,
neatly cut in the window square, and fitted with a circular glass
cover with corresponding holes working on a centre pivot, are also
very effective for admission or extraction of air. Moore’s sliding
ventilator consists of oblong vertical holes, with the cover sliding
between guides horizontally, the principle being the same as in
the circular ventilator, but it is more suited for the top of shop
fronts or shallow fanlights. These are all made by J. Moore and Sons,
Sekforde Works, St. James’s Walk, Clerkenwell Green, E.C.
Another simple method of admitting fresh air to a room consists in
leaving an aperture in the external wall, at a level between the
ceiling of one apartment and the floor of the room immediately above,
then to convey the fresh air through a channel from the external
wall to the centre of the ceiling of the apartment below, where the
air can be admitted by an opening, and dispersed by having a flat
board or disc to impinge against, suspended 4 in. or 6 in. below the
opening of the ceiling, and so scattered over the room. The cold air,
however, thus admitted, plunges on the heads of the occupants of the
room and mixes with the hot air which has risen near the ceiling.
A top window-sash lowered a little to admit fresh air has the same
disagreeable effect, the cold air being drawn towards the floor by
the chimney draught, and leaving the hot air to stagnate near the
ceiling. In any siphon system placed vertically the current of air
will enter by the short arm, and take its exit by the long arm, and
thus the chimney flue acts as the long arm of a siphon, drawing the
fresh air from the nearest opening. Fresh air may be introduced
through perforations made in the woodwork of the bottom rail of the
door to the room, or through apertures in the outer wall, admitting
the fresh air to spaces behind the skirting board, and making the
latter perforated. The only objection to this plan is the liability
for vermin to lodge between the skirting board and the wall. This may
be prevented by covering the outside apertures with perforated zinc,
but such covering also helps to keep out the full supply of fresh air.
Butler recommends, while admitting the cold air through side
walls near the floor level, and allowing the foul air to escape
at the ceiling, that the fire draught should be maintained quite
independent of the air inlet to the room, the requisite amount of
air for combustion being supplied by a separate pipe led through the
hearthstone with its face towards the fire, the latter acting as a
pump, which is sure to procure its own allowance from the nearest
source; thus the draught which would otherwise be felt by the fire
drawing its supply from the inlet across the room is considerably
reduced. The foul air may enter the ceiling in the centre, and be
conducted by an air-flue either to the outside or to the chimney.
The chimney is the best extractor, as its heated condition greatly
favours the ventilating power.
Dr. Arnott was one of the first to draw attention to the value of a
chimney as a means of drawing off the foul air from the interior of
an apartment. He invented a ventilator consisting of a well-balanced
metallic valve, intended by its instantaneous action to close
against down draught and so prevent the escape of smoke into a room
during the use of fires. If the fire is not alight, what is known
as the register of the stove should be closed, or a tight-fitting
board placed in front of the fireplace, with the adoption of all
chimney-ventilators fixed near the ceiling.
[Illustration: 27. Harding’s Ventilator.]
Harding’s ventilators are better known in the north of England than
the south. They are recommended by Pridgin Teale, surgeon to the
General Infirmary at Leeds, as a means of securing freshness of
atmosphere without draught, and free from all mixture of dust, soot,
or fog. The outside air is conducted through a grate and aperture in
the wall about 7 ft. 6 in. above the floor level, where it is made
to pass through a series of small tubes fixed at an angle of about
30° with the wall. The currents of air are said to be compressed
while passing through the tubes, but to expand and diffuse in all
directions as soon as they are liberated into the apartment. In all
filtering arrangements it must be remembered that if air is to pass
through a screen or filter without retarding the current entering
the room through a tube, the area of the screen must be greater than
the area of section of the tube. This can be effected by placing
the screen diagonally within the tube which admits the air. In some
buildings the filter is dispensed with, and the apparatus is used
simply to diffuse the air as it enters the room. An outlet for the
vitiated air is provided by the chimney flue, either through the
fireplace or by a mica valve placed in the flue near the ceiling.
In rooms where flues do not exist an air extractor is provided,
consisting of two perforated cones and a central tube. The external
air impinging upon the perforated cones is deflected, creating an
induced current up the vertical tube, drawing the foul air from the
interior of the room, and expelling it through the perforations.
In fixing the extractor, a wooden base or frame is placed on the
ridge and covered with lead to make it watertight; the extractor
is then placed over this and fixed in the ordinary manner. A small
inner cone is provided simply to prevent rain from getting into the
tube. Harding’s extractors are so designed that they may be easily
fixed inside an ornamental turret without in any way affecting their
action. They can be obtained in London from Strode & Co., at prices
varying from 15_s._ to 6_l._ and upwards. Their action is illustrated
in Fig. 27: _a_, wall; _b_, grating outside; _c_, filter.
Another system for admitting fresh air into a room, free from fog and
other impurities, is that recommended by the Sanitary Engineering
and Ventilating Co., 115, Victoria Street, Westminster. They provide
for the introduction of fresh air in vertical currents by means of a
suitable number and disposition of vertical tubes, varying in size,
section, and weight according to each special case. The current can
be regulated in amount by throttle valves, and the heated or vitiated
air is removed by means of exhaust ventilators, placed directly over
the roof or in connection with air flues and shafts. The exhaust
ventilator is thus described by the makers: There are no working
parts to get out of order, and no attention is required to ensure
its constant action. In this respect, a great improvement is claimed
over the numerous forms of revolving cowls, which require occasional
lubrication, otherwise the working parts become corroded and the cowl
ceases to act. They are made of circular or rectangular section,
or other shapes to suit special circumstances. One great merit of
the system is the element of length which is introduced by means
of the tube arrangement, and thus a current is continually passing
which diffuses itself over the room. The system admits of a patent
air-cleansing box being built into the wall at the foot of the tube,
fitted with special deflector plates and a tray to hold water or,
when necessary, disinfectants. When the arrangements of furniture
or fittings in a room preclude the use of vertical tubes fixed near
the ground, they recommend the substitution of a ventilating bracket
fixed at 6-7 ft. above the floor. This bracket may contain an air
purifying or cleansing box; if required, a valve is provided for
regulating the admission of fresh air, and a 9 in. by 6 in. hinged
air grating to cover the opening outside. The air-cleansing box is
illustrated in Fig. 28: _a_, inside of room; _b_, floor; _c_, trough
or tray for holding water or disinfectant fluid; _d_, tube.
[Illustration: 28. Sanitary Ventilating Company’s Ventilator.]
Boyle’s patent self-acting air-pump ventilators are well known,
and are found to answer well in their continuous action under all
varieties of wind pressure; they are often adopted without any
inquiry being made as to the scientific principles on which they are
constructed. They consist of 4 sections, each acting independently of
the other. The exterior curve baffle-plate prevents the wind blowing
through the slits formed in the immediate interior plates, and
tends to concentrate the current. These interior plates are curved
outwards, so as to take the pressure off the vertical slits, which
form a communication with the internal chambers, through which the
air impinges on inner deflecting plates, and is further directed by
the radial plates. The external air impinging on the radial plates
is deflected on to the side plates, and creates an induced current.
In its passage it draws the air from the central vertical chambers,
expelling it at the opposite opening. The vitiated air immediately
rushes up the shaft connecting the ventilator with the apartment to
be ventilated, extracting the air and producing a continuous upward
current without the possibility of down draught. The partitions
separating the chambers prevent the external air being drawn through
the slits upon which the wind is not directly acting. The whole
arrangement being a fixture, with no mechanical movement, it is never
liable to get out of order, and the apparatus can be easily fixed
over a wood base or frame covered with zinc or lead to secure a good
water-tight connection. Where Boyle’s ventilators are used the air is
renewed imperceptibly, the vitiated air being extracted as rapidly as
it is generated.
A somewhat similar arrangement to Boyle’s ventilator is patented by
Arnold W. Kershaw, of Lancaster, and consists of 3 rims of deflectors
or plates with openings in each, so arranged that the openings in
one rim are opposite the deflectors in the next inner or outer rim,
the effect being that whatever the direction of the wind, it passes
through the ventilator without being able to enter the central shaft,
and in passing creates a partial vacuum, which induces an upward
current in the upcast shaft without the possibility of down draughts.
Both Boyle’s and Kershaw’s roof ventilators are suitable for fixing
in ventilating towers or turrets. While Kershaw’s is somewhat simpler
in construction, Boyle’s is said to possess the additional advantage
of preventing the entrance of snow by the curve in which the inner
plates are fixed. In the case of chimney flues where there is any
obstruction that breaks the wind and produces a swirl, such as would
be caused by close proximity to higher buildings or raised gables, a
down draught may be prevented by the use of a properly-constructed
chimney cowl. Kershaw’s chimney cowl is a modification of his
pneumatic ventilator, and consists of deflecting plates so arranged
that there is no possibility of a down draught. Boyle’s chimney cowl
is better known than Kershaw’s, and is very effective. It consists
of deflecting plates so fixed that if a body of air is forced in at
the false top, instead of passing down the vent, it is split up by
an inner diaphragm, deflected over the real top, and passed over at
the side openings, thus checking the blow down and assisting the up
draught. Kershaw’s patent inlet and air diffuser consists of a tube
connection between the outside and inside of an apartment rising
vertically on the inside, the upper extremity having radiating
plates, which diffuse the incoming current. Generally speaking, a
sufficient amount of fresh air enters under the door to a room or
between the window sashes or frames; but in apartments where doors
and windows fit tightly, some arrangement for the admission of fresh
air becomes indispensable. In this climate, during 7 months of the
year, the external air is usually too cold to be admitted directly
into the room.
The plan of admitting fresh air to a space behind the grates, leading
up the air through channels on each side of the fireplace, and
ultimately passing it through perforated gratings within the wall
or through perforations in the skirting board on each side of the
fireplace cannot be commended, as the passages are apt to get choked
up with dust, and the temperature of the air cannot be well regulated
in its passage into the room. The true object of a fire and chimney
flue should not be to supply fresh air, but to extract it after it
has done its work.
[Illustration: 29. Boyle’s Air-cooler.]
Fig. 29 illustrates Boyle’s arrangement for cooling the air entering
a room in hot weather. It consists of an air-inlet tube of bracket
form, made of iron. The part which penetrates the hole in the wall
has an outer casing, so that a space of about ½ in. is left between,
which is packed with a non-conducting substance, for the purpose of
preventing the heat from the wall penetrating into the interior of
the opening and acting upon the blocks of ice, which are placed in a
movable drawer, and kept in position by means of open galvanised iron
or copper-wire netting. The front of the drawer is also double, and
packed same as casing. The outer air entering through the grating is
deflected by a metal shield on to the suspended blocks of ice, and
from thence on to the ice at the bottom of the drawer, and thence
up the tube into the room. The air is not only cooled, but purified
thoroughly from dust. See also p. 991.
=Warming.=--In connection with warming an apartment, it is obviously
a necessary condition that the warmth shall be conserved as much as
possible. Hence there is an evil in having too much glass, as it
cools the room too fast in the winter season: 1 sq. ft. of window
glass will cool 1½ cub. ft. of warm air in the room to the external
temperature per second; that is, if the room be warmed to 60° F., and
the thermometer stands at 30° F. outside, there will be a loss of
90 cub. ft. of warm air at 60° per second from a window containing
a surface of glass of 60 sq. ft. In colder climates than that of
England, this subject is of much greater importance. In America, for
instance, during the cold weather, there will always be found, no
matter how tightly or closely the sashes are fitted and protected
with weather-strips, a draught of cold air falling downward. This
arises from the contact of the heated air with the cold glass, which
renders the air cooler and heavier, and causes it to fall. The
air, at the same time, parts with a considerable proportion of its
moisture by condensation upon the glass. The cold air thus formed
falls to the floor, forming a layer of cold air, which surrounds
the feet and legs, while the upper part of the body is enveloped in
overheated air. The layers of cold and warm air in an apartment will
not mix. The warm air will not descend, and the cold air cannot go
upward, except the one is deprived of its heat by radiation, and the
other receives its heat by actual contact with a heated surface. This
radical difference in the upper and lower strata of atmosphere of the
rooms, in which people live during the cold season, is the prolific
cause of most of the throat and lung diseases with which they are
afflicted. Double windows to the houses, therefore, would not only be
a great economy as to fuel, but highly conductive to human longevity.
There are only two ways in which dwelling-houses can be heated,
namely, by radiant heat and by hot air. The former is produced by the
open fire, and by it alone. The latter is obtained in various ways.
The question whether we shall use hot air or radiant heat in our
rooms is by no means one to be lightly passed over. Instinct tells us
to select radiant heat, and instinct is quite right; it is so because
radiant heat operates in a very peculiar way. It is known that as
a matter of health it is best to breathe air considerably below
the natural temperature of the body--98° F.; in air heated to this
temperature most persons would in a short time feel stifled. But it
is also known that the body likes, as far as sensation is concerned,
to be kept at a temperature as near 98° F. as may be, and that very
much higher temperatures can be enjoyed; as, for example, when we
sit before a fire, or bask in the sun. Now radiant heat will not
warm air as it passes through it, and so, at one and the same time,
we can enjoy the warmth of a fire and breathe that cool air which
is best suited to the wants of our system. Herein lies the secret
of the popularity of the open fireplace. But in order that the open
fireplace may succeed, it must be worked within the proper limits of
temperature. If air falls much below 40° F. it becomes unpleasant to
breathe; and it is also very difficult to keep the body warm enough
when at rest by any quantity of clothes. In Russia and Canada the
temperature of the air outside the houses often falls far below zero,
and in the houses it cannot be much above the freezing-point. Here
the open fire fails; it can only warm air by first heating the walls,
furniture, and other materials in a room, and these, in turn, heat
the air with which they come in contact. But this will not do for
North American winters; and accordingly in Canada and the United
States the stove or some other expedient for warming air by direct
contact with heated metal or earthenware is imperatively required.
But this is the misfortune of those who live in cold climates, and
when they ask us to follow their example and take to close stoves
and steam-pipes, and such like, they strongly remind us of the fable
of the fox who had lost his tail. How accurately instinct works in
the selection of the two systems is demonstrated by the fact that a
succession of mild winters is always followed in the United States by
an extended use of open grates; that is to say, the English system
becomes, or tends to become fashionable, while, on the other hand,
a succession of severe winters in this country brings at once into
favour with builders and others a whole host of close stoves and
similar devices which would not be looked at under more favourable
conditions of the weather. While English winters remain moderately
temperate, the open fireplace will enjoy the favour it deserves,
as not only the most attractive, but the most scientific apparatus
available for warming houses. (_Engineer._)
Heat radiated from a fire passes through the air without increasing
its temperature, in the same manner that the sun’s rays in warming
the earth pass through and leave the atmosphere at the higher
altitudes so bitterly cold that water and even mercury will freeze:
it is for this reason that open fires should be lighted some time
before the apartment is required for use, so that firstly a glowing
fire be obtained (flames do not radiate any material quantity of
heat, and practically heat by contact only), and secondly the
surrounding objects, walls, &c., be heated by radiation, and these in
their turn warm the air.
In discussing the various methods of warming, it will be convenient
to classify them under general heads.
To put the reader upon a more familiar basis with this subject, a
short explanation of the cause of heat will be here given. Combustion
is the chemical union of oxygen (contained in the air) with some
other substance for which it has an affinity; as applied to coal, it
is the combining of oxygen and carbon producing carbonic acid gas,
and it is known to every one that all chemical combinations evolve
heat.
Combustion may be said to be complete when coke, wood charcoal, or
anthracite coal is burnt, as there is no smoke, the up current is
colourless, and these fuels burn quite away, leaving nothing except a
little ash, &c., which originally consisted of earthy impurities in
the fuel. Ordinary coal contains bitumen (pitch) in its composition,
which at a temperature of about 500° to 600° F., distils off as a
smoky gas (carbon and hydrogen), but at a higher temperature this
is ignited, forming flame by the union of oxygen with the smoke
(carbon); the main principles of underfed, smoke-consuming grates are
based upon this, with the object of causing all gaseous products from
the fuel to pass through the incandescent portion of the fire and so
render the consumption of the fuel complete, as will be explained
later on.
A good authority says that “the correct method of warming is to
obtain everywhere, at will, the warmth most congenial to the
constitution with air as pure as blows at the mountain top,” and it
might have been added “without an unreasonable consumption of fuel.”
_Open Grate._--The ordinary open grate is too familiar to need any
description, but it is wasteful of fuel to a degree that could only
be tolerated in a mild climate where fuel was cheap. As a matter of
fact, only some 10-12 per cent. of the heat generated in an open
grate is utilised, the remainder going up the chimney. But this very
fault is in one sense a virtue, in that it performs the ventilation
of the apartment in an eminently satisfactory manner. By the addition
of a contrivance for regulating the combustion in au open grate, the
fuel consumption is much reduced, the combustion is rendered more
perfect (diminishing or preventing smoke), the radiated heat is much
increased, while the appearance of an open grate is retained, though
it is in reality converted into an open stove.