Improvements in Apparatus for Preventing Condensation of Moisture Upon Cold Surfaces.
Year: 1897

page_text: Date of Application, 15th Dec., 1897
Complete Specification Left, 17th June, 1898-Accepted, 15th Mar., 1899
PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Preventing Condensation of Moisture
Upon Cold Surfaces.
I, EDWARD HERBERT MAULE, of 199, Coventry Road, Small Heath, Birming-
ham, Professional Brewer, do hereby declare the nature of this invention to be
as follows;
This invention relates to an improved means of preventing condensation upon
any cold surface as for example a thin wall or a glass window.
It is well known that when the temperature of the air outside a
room is
sensibly below that of the room, condensation takes place upon the windows.
This appears to be by reason that the warmer air in the room is able to carry a
greater quantity of vapour than the external air and no moisture or dew is
deposited upon any mirrors or other conducting surfaces in the room which have
acquired the same temperature as the air of the room; but when this air carrying
as it usually does a large quantity of vapour comes in contact with a surface
below its dew point in temperature, the air next the surface becomes itself reduced
to below its dew point and therefore unable to carry all its vapour-some of
which it deposits upon the surface in question in the form of dew or condensed
steam successive layers of air repeat this process until the window or wall or
whatever the cold surface may be acquires a layer of dew sufficiently thick in the
case of a window to give it a frosted or steamed appearance and to seriously
impair its transparency.
The formation of dew upon certain surfaces is objectionable and the object of
my invention is both to prevent its deposit and to remove the deposit of dew if
formed both actions taking place the one or other in greater or lesser degree as
the apparatus is at work."
Primarily the means employed for preventing and removing the deposit of dew
are to cause a current of dry air to move over the surface to be protected and the
apparatus consists essentially of a cockle or other suitable apparatus for heating
air and a blower for forcing this air through pipes, with nozzles for injecting
the air upon the surfaces to be protected, and an apparatus for drying the air
may be added.
In the case of shop windows, steaming is usually objectionable and apparatus
suitable for preventing this will now be described.
mean air with a
com-
The precise details of this my invention may be considerably varied without
departing from its nature but broadly speaking my invention consists in forcing
by any mechanical means (or by means of a heat induced draft) a film of com-
paratively dry air over the surface to be protected by the expression
paratively dry air" I
dew point below the tem-
perature of the surface to be protected. Steaming in this case only
takes place in cold weather and consequently the external air cannot carry a
heavy per centage of vapour. It is therefore unnecessary to dry the air.
supply of air is led from the outside, roughly filtered to remove dusty particles
A

page_text: &c., and passed through the heating apparatus after which it is distributed over
the surfaces to be protected.
The fan or blower or pump to drive the air would preferably be fixed between
the filter and the heater so as to deal with the air before it is expanded in the
heater. Hot air lends itself to distribution over a flat plate shop window, delivery
being made out of tubes or their equivalent, standing vertically or approximately
so, below the window and delivering at the lower edge. The air being hot and
also having a velocity shoots out of the pipes up the surface of the window over
which it spreads and rises by reason of being lighter than the air of the shop.
Instead of using a blower or the like, a form of induced draft by heat may be
made by burning a gas jet or by placing a hot body or injection of hot air at
the bottom of the tubes above referred to, the air being heated and caused to
rise up the tubes and acquire a velocity by the burners or other means.
Dated this 14th day of December 1897.
CHARLES T. POWELL,
Applicant's Agent.
İmprovements in Apparatus for Preventing Condensation of Moisture
upon Cold Surfaces.
I, EDWARD HERBERT MAULE, late of 199, Coventry Road, Small Heath, Bir-
mingham, now of 6, Princes Chambers, Corporation Street, Birmingham, in the
County of Warwick, Brewer, 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:-
-
My invention relates to improved means for preventing the condensation of
moisture contained in the air upon cold surfaces and is especially adapted for
preventing the condensation of moisture on panes of glass such as shop windows
for example, and it is in reference to preventing condensation on windows that I
will describe my invention.
When the temperature of the air outside a room is sensibly below that of the
air in the room condensation of vapour takes place upon the inner panes of the
windows. The following appears to be the reason. The warmer air in the room
carries a greater quantity of moisture or vapour than the colder external air and
consequently when the warmer air comes in contact at the window panes with a
surface below its dew-point in temperature this air becomes itself reduced to a
temperature below its dew-point and is therefore unable to carry all the moisture
or vapour which it contained some of which deposits on the cold surface of the
window pane in the form of dew or condensed steam: this deposition of con-
densed vapour continues until a layer of dew is deposited on the window pane
giving it a frosted or steamed appearance and seriously impairing its trans-
parency.
According to my invention the means employed for preventing and removing
the deposits of dew are to cause a current of heated dry air to move over the
surface to be protected and the apparatus consists essentially of a cockle or other
suitable apparatus for heating the air and a fan or blower for forcing this air
through pipes with nozzles or delivery pipes for injecting the air upon the sur-
faces to be protected, an apparatus for drying the air being added if required.
The precise details of this my invention may be considerably varied without
departing from its nature but broadly speaking my invention consists in forcing
.

page_text: 66
by any mechanical means or by means of a heat induced draught a film of heated
air comparatively dry over the surface to be protected, by the expression com-
paratively dry air" I mean air with a dew-point below the temperature of the
surface to be protected. When steaming on windows takes place in cold weather
the external air cannot carry a heavy percentage of vapour and it is therefore
unnecessary to dry the air in this case.
A supply of air is led from the outside roughly-filtered to remove dust particles
and like impurities and passed through the heating apparatus after which it is
distributed over the surfaces to be protected. The fan or blower or pump to
drive the air is preferably fixed between the filter and the heater so as to deal
with the air before it is expanded in the heater.
Hot air lends itself to distribution over a flat plate shop window delivery being
made out of tubes or their equivalents standing vertically or approximately so
below the window and delivering at the lower edge. The air being hot and also
having a velocity shoots out of the pipes up the surface of the window over
which it spreads and rises by reason of its being lighter than the air of the shop.
Instead of using a blower or the like a form of induced draft by heat may be
made by burning a gas jet or by placing a hot body or injection of hot air at the
bottom of the tubes above referred to, the air being heated and caused to rise
up the tubes and acquire a velocity by the burners or other means.
I will describe my invention with reference to the accompanying drawings
premising that I do not limit myself to the precise details shewn.
Figure 1 shews in front elevation and Figure 2 in cross section an arrange-
ment according to my invention for supplying heated air to the inner surface of
a shop window.
Figure 3 shews a modification of the same in front elevation.
Figure 4 shews in front elevation and Figure 5 in cross section another modifica
tion according to this invention. Figure 4* is a modification shewn in plan,
Figure 6 shews in front elevation and Figure 7 in cross section a modified form
of the arrangement shewn in Figures 4 and 5.
Figure 8 shews in cross section drawn to a larger scale a hot water device for
heating the air and
Figures 9 and 10 shew in front elevation and cross section respectively an
arrangement in which electricity is employed for heating the air.
A
In the arrangement shewn in Figures 1 and 2 A is the air main situated
below the window a to which the apparatus is to be applied. Air drawn prefer
ably from the outside is supplied under pressure by the fan B being heated on
its way to the window by passing through the cockle C which is heated by the
Bunsen gas burner c. The heated air is supplied through the vertical delivery
pipes D which terminate at the base of the window pane a which pipes may be
fitted with valves d for regulating the supply of air. a indicates the wall sup-
porting the window. When the apparatus is in use the air is caused to flow at a
gentle velocity by the fan B through the main A becoming heated on its passage
through the cockle C; on passing out from the delivery pipes D the air flows up
vertically against the inner surface of the glass and spreading in a thin filia r
sheet effectually removes moisture deposited thereon. Figure 3 shews a modified
arrangement in which an air main A of smaller diameter is employed with injec
tion nozzles a discharging into the vertical delivery pipes D, air from the shop
or room being drawn in at the space a³ between the said nozzles and the pipes D.
In this case the air is heated by any suitable means to a higher temperature than
in the first described arrangement before reaching the nozzles, and is supplied at
a higher pressure.
In the arrangement shewn in Figures and 5 a fan is dispensed with; the
air is heated by the Bunsen gas burners c situated beneath the delivery-pipes D,
which are contained in casings D₁ the latter being formed in one with the air
main A, and provided with a lid or cover d.
The burners c cause a draught of hot air which draws in air by the main A
"

page_text: and distributes it heated at a sufficient velocity through the vertical pipes D in
a thin sheet or film which travels up against the inner surface of the window.
The gas is supplied through a main provided with a swivel joint at so as to
allow of the gas jets being readily lighted by removing them from the brackets c
and letting the mains then swing back on their joints. In place of the inner
draught or delivery pipes D, I may use parallel metal plates D2 as indicated in
plan in Figure 4* arranged in the outer casing D' extending the whole length
of the apparatus and bent at the ends to form an inner rectangular lining.
Figures 6 and 7 shew an arrangement similar to Figures 4 and
except that
the outer casing D is replaced by pipes D³ provided with lids or covers these
pipes are concentric with the draught or delivery pipes D and may in some cases
be dispensed with.
Figure 8 shews another arrangement for heating the air in which hot water is
used as the heating agent.
A is the air main, 1) are the outer vertical pipes or casing and D the inner
delivery or draught tubes.
F indicates the water tube in which is a small tube f open at both ends to
promote circulation; 2 is a washer to assist in causing the proper circulation of
the water. The water which is heated by any suitable means is supplied through
a main G from which the vertical water tubes enclosed in the air tubes or casing
rise at intervals.
Figures 9 and 10 shew an electrical device for heating the air. In this arrange-
ment the outer casing D' is made in one with the air main A; in the said casing
spiral coils of metal if are arranged preferably so as to form hollow tubes through
which a current of electricity is passed, by the conductors h, of sufficient magni-
tude to heat the coils to the required temperature. By this means an induced
draught of hot air is obtained for application to the window and fans or the like
air forcing apparatus are dispensed with.
From the foregoing it will be understood that a current of heated air is applied
at the base of the window from which the dew or moisture is to be removed and
caused to travel up as a film or sheet as aforesaid at a slow rate of velocity in
straight vertical lines or approximately so between the inner surface of the
window and the air in the room, the said air being preferably heated to a tem-
perature of say about 150° F. for a room where the temperature does not
exceed 70° F. By the improved means described double panes of glass which
have been hitherto used are dispensed with and the objectionable deposits of
dew or moisture on the glass obviated.
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 apparatus for preventing the deposit of dew or vapour on windows or
the like the combination of means for admitting air to a channel, in which it is
heated out of contact with the air in the apartment or shop, and thence passed
to orifices, delivery pipes or casings through which it is caused to flow at a gentle
velocity so as to spread and form an upwardly ascending film of hot air between
the surface of the glass of the window on the one side and the air in the apart-
ment or shop on the other side substantially as described.
2. The several combinations and arrangements of parts constituting apparatus
for removing or preventing condensed vapour or dew on windows or the like
substantially as hereinbefore described and shewn in the drawings.
Dated this 17th day of June 1898
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents.