IMPROVEMENTS IN VENTILATORS
Year: 1884

page_text: I, JAMES GRIEVE LORRAIN of the Whitehall Club, Parliament Street, in the
City of Westminster, Consulting Engineer, do hereby declare the nature of my
Invention for IMPROVEMENTS IN VENTILATORS to be as follows:-
My invention relates to improvements in Ventilators whereby certain advantages
are obtained.
A common method of ventilation is by means of revolving fans or propellers.
There are two leading types of such methods of ventilation, one in which the fan
or propeller is caused to revolve by natural means such as the pressure of currents
of air on vanes as in the well known Boyle ventilator, and the other where the fan
or propeller is caused to revolve by artificial means by mechanical power applied
direct, as in the well known Blackman, Guibal, & Roots systems, or by Electrical
power as in electro-motors attached to fans or propellers.
My invention applies to the last case, and its object is to make such ventilators
automatic in their action; so that they will always act when the necessity for
ventilation arises, and cease to act when such necessity no longer exists, and this
without any attention or supervision being required.
"
In carrying my invention into effect I introduce into the electric circuit what
I may call a "thermal contact maker for the purpose of closing and opening the
said circuit when required. A convenient form of thermal contact maker consists
of an ordinary thermometer with a platinum or other wire in the tube above the
mercury and in electrical connection with one pole of the battery or generator,
whilst the inercury is in electrical connection with the other pole, so that when the
Inercury rises in the tube and reaches the wire the electric circuit is closed; but I
prefer to employ for this purpose a thermostatic band consisting of two rods, plates,
bars or strips of metal soldered or otherwise fastened together and having different
coefficients of expansion under the influence of heat. One end of this band may be
fixed in any convenient manner and to the other may be attached a contact piece
preferably of the form of a screw passing through the end of the said thermostatic
band and so capable of adjustment. This contact piece is in electrical connection
with one pole of the battery or generator, whilst the other pole of the battery or
generator is in electrical connection with another contact piece opposite that side
of the thermostatic band on which is the metal having the lowest coefficient of
expansion, but not in electrical connection therewith when the circuit is open,
CD 121

page_text: This contact piece may also be of the form of a screw and capable of adjustment.
I prefer to tip both of these contact pieces with platinum so as to prevent oxidation
or sticking. Other forms of thermal contact maker will readily suggest themselves,
such as would make contact through the expansion of a wire (by heating) or of a
spiral, or corrugated band &c. .I prefer to place the thermal contact maker at or
near the highest point in the enclosed space to be ventilated.
The action of my apparatus is as follows:-As the air becomes foul & hot it
communicates its heat to the thermostatic band which. is thus caused to expand.
The coefficients of expansion of the two metals being different the band will curve
round in the direction of the metal having the lowest coefficient of expansion until
the two contact pieces meet, when the circuit will be closed, and the current from
the battery or generator call the electro-motor into action and drive the fan or
propeller. When the heated air has been expelled, and the temperature has fallen,
the metals will contract, the band be unbent; the contact points separated, the
circuit opened, and the fan or propeller brought to rest. By regulating the distance
through which the band has to bend, the mercury rise, or the material bearing a
contact point expand before the circuit is closed, the apparatus can be adjusted to
act at any desired temperature.
It is obvious that the thermostatic band may consist of more than two strips,
bars, plates or rods, that it is not necessary that they should be of metal, & that
the band may be constructed or arranged in any convenient shape.
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In 11001

page_text: I, JAMES GRIEVE LORRAIN of The Whitehall Club, Parliament Street, in the
City of Westminster Consulting Engineer do hereby declare the nature of my
invention for IMPROVEMENTS IN VENTILATORS 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 improvements in Ventilators whereby certain advantages
such as reliability certainty and automaticity of action are obtained.
".
A common method of ventilation is by means of fans or propellers. There are
two leading types of this method of ventilation, one in which the fan or propeller
is caused to revolve by natural means such as the pressure of currents of air on
vanes, blades or sails and the other where the fan or propeller is caused to revolve
by artificial means either by mechanical power applied direct as by a gas steam or
water motor or by electrical power applied direct as in electromotors attached to
fans or propellers. Another common method is by the use of Valves actuated by
one of the foregoing methods. My invention applies to the cases where electricity
is employed, and its object is mainly to make such ventilators automatic in their
action, so that they will always act when the necessity for ventilation arises and
cease to act when such necessity no longer exists and this without any attention or
supervision being required.
I
In carrying my invention into effect I introduce into the electric circuit what
may
call a thermal contact maker for the purpose of closing and opening the said
circuit when required. A convenient form of thermal contact maker consists of an
ordinary thermometer with a platinum or other wire in the tube above the mercury
and in electrical connection with one pole of the Battery or Generator or source of
electricity whilst the mercury is in electrical connection with the other pole so that
when the mercury rises in the tube and reaches the wire the electric circuit is
closed. I prefer however to employ as a thermal contact maker a thermostatic
band consisting of two rods, plates, bars or strips of metal soldered or otherwise
fastened together and having different coefficients of expansion under the influence
of heat. One end of this band may be fixed in any convenient manner and to the
other may be attached a contact piece preferably of the form of a screw passing
through the end of the said thermostatic band and so capable of adjustment. This
contact piece is in electrical connection with one pole of the Battery or Generator
or source of electricity whilst the other pole of the Battery or Generator or source
of electricity is in electrical connection with another contact piece opposite that
side of the thermostatic band on which is the metal having the lowest coefficient
of expansion but not in electrical connection therewith when the circuit is open.
This contact piece may also be of the form of a screw and capable of adjustment.
I prefer to tip both of these contact pieces with platinum so as to prevent oxidation
and sticking. Other forms of thermal contact maker will readily suggest them-
selves, such as would make contact through the expansion of a wire bar or strip
under the influence of a rise of temperature or of a spiral or corrugated baud &c.
but it is not necessary to specify all the forms and modifications of thermal contact
maker which might be employed in carrying out any invention.
I prefer to place the thermal contact maker at or near the highest point in the
space to be ventilated.
The action of my apparatus is as follows. As the air becomes foul and hot it
communicates its heat to the thermostatic band which is thus caused to expand.
The coefficients of expansion of the two metals being different the band will curve

page_text: round in the direction of the metal having the lowest coefficient of expansion until
the two contact pieces meet when the circuit will be closed and the current from
the Battery or Generator or source of electricity call the electro-motor into action
and drive the fan or propeller or open the valve. Similarly the rise of the mercury
in a thermometer as mentioned previously, or the expansion of a bar or strip or
spiral or corrugated band will close the circuit and cause the electromotor to be
called into play. When the heated air has been expelled or exhausted & the
temperature has fallen the metals will contract the band be unbent the contact
points separated and the circuit opened and the fan or propeller brought to rest and
the valve closed. The fall of the mercury in the thermometer or the shrinking of
the bar strip spiral or corrugated band will, similarly open the circuit.
By regulating the distance through which the bar has to bend, the mercury rise,
or the bar, strip, spiral or corrugated band expand before the circuit is closed, the
apparatus can be adjusted to act at any desired temperature.
It is obvious that the thermostatic band may cousist of more than two strips
bars plates or rods and that it may be constructed or arranged in any convenient
shape or form.
The velocity and power of the motor and consequently of the fan or propeller
where such is employed may be regulated by varying the current passing through
the electromotor. This may be effected by any of the well known methods of
varying the current in a circuit such as by varying the resistance of the circuit,
automatically or otherwise, or varying the electromotive force, automatically or
otherwise, or by bringing into the circuit or removing therefrom a greater or lesser
number of producing or transforming elements, automatically or otherwise as will
be readily understood.
One method of introducing more elements into a circuit is by providing a
number of contact points so connected up that the further the band bends or the
inercury rises or the contact piece expands the more elements are cut in, but I do
not find that this works well-in practice as the hot air begins to be removed and
the temperature to fall as soon as the first contact point is reached and the fan
called into play or the valve opened so that the other contact points are not
reached at all.
When a number of fans or propellers or valves are thus actuated from one
electrical centre I may arrange the various motors driving them in derived circuit
or multiple or parallel arc.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is
1. In a ventilator consisting of an electrically driven or actuated fan or propeller
or valve the use of a thermal contact maker substantially as described.
2. In a ventilator consisting of an electrically driven or actuated fan or propeller
or valve the use of a thermal contact maker for the purpose described.
3. In a ventilator consisting of an electrically driven or actuated fan or propeller
or valve the arrangement for regulating the temperature at which the thermal
contact maker will act by the distance through which expansion or bending takes
place before the circuit is closed substantially in the manner and for the purpose
herein described.
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