Improvements in Thermostatic Apparatus for Controlling Air Admission Valves.
Year: 1891

page_text: Date of Application, 17th Sept., 1891
Complete Specification Left, 17th June, 1892-Accepted, 10th Sept., 1892
PROVISIONAL SPECIFICATION.
Improvements in Thermostatic Apparatus for Controlling Air
Admission Valves.
I JAMES MCHARDY of Fairfax House Chiswick Scientific Expert do hereby
declare the nature of this invention to be as follows:-
This invention, which consists of improvements in thermostatic apparatus for
controlling air admission valves and which has for its object the application of the
principle, or natural law of contraction and expansion, to the arresting or releasing
of cold or heat, artificially supplied, or the admission of natural air for ventilation
wherever temperature is concerned, may be carried out somewhat as follows.
Any material may be used in the construction of the said apparatus provided
that by its contraction or expansion it may so act upon mechanical parts, or
complete such electric circuits as may be brought to bear upon a valve or valves
(or any kind of regulating equivalents) for the admission of more or less heat or
cold, whether chemically or mechanically produced, or from the atmospheric air.
The simplest form of the said invention may thus he briefly described :-
Given a means of refrigeration by compressed air, as applied to cool an
apartment. A rod of suitable material may be so fixed, in conjunction with a
valve for the admission of the air, and so exposed to the mean temperature of the
apartment, that, upon its temperature falling to a given degree (which of course
decreases its length) the contraction of the said rod will cause the valve to close
and arrest the supply of cold air: Or; the converse if the object be to raise
the temperature by the admission of hot air, the contraction of the said rod may
be applied so as to open a valve for the free admission of such hot air. In either
case, the heat or cold may be turned on in confined apparatus, such as pipes &c.,
or it may be allowed to escape from such perforated apparatus as may be found
suitable for the purpose of diffusion, or, as a matter of course, the said heat or
cold may be directed to a given point, if circumstances should arise to make such
an arrangement necessary. In some instances it may be advisable to multiply the
expansive action of a rod of limited dimensions, by means of levers, the pulley and
axle, the compound block and tackle or any mechanical equivalent: or, it may be
possible to cause a considerable length of flexible material to occupy a limited
space, by winding it over a series of loose pulleys.
In all cases a suitable regulating joint will be provided so that dimensions may
be adjusted to admit of action whenever the mean temperature rises above or falls
below a given degree. A right and left thread, a swivel-nut or if necessary a cam
(plain or graduated) may be especially used to regulate the said action.
Electricity, steam, or any motive power which may be readily available, may in
like manner be regulated to actuate such apparatus as may be suitable for the
admission of cold or heat or atmospheric air, by means of the said apparatus.
Thus, for example, the contraction and expansion of mercury, spirits of wine or
any suitable material, may be caused to complete or disconnect a circuit in any
convenient manner, for the purpose of opening or closing a valve or ventilator, by
electro-magnetic or any available power. Or, the thermometric action may be
caused to act directly on any suitable appliance in connexion with the regulation
of temperature.
Or, it may be found possible to ascertain the exact quantity of liquid, which, at
a given temperature, will suffice to maintain a required mean temperature, by
merely cooling the surrounding air, in which case the cold or heat may be directly
introduced, so that the fluid, by its contraction or expansion, or freezing, may
arrest the said supply of heat or cold. If, for example, a conical vessel of sufficient
11

page_text: strength, with suitable outlets for the air, be filled with water, and a supply of
compressed air be led on, the water in freezing will so expand as, practically, to
freeze up the apertures from which the air is admitted. The supply being stopped,
the ice will gradually absorb the heat from the surrounding atmosphere until the
cold air be once more released to refrigerate the water.
It is nevertheless manifest that in such an appliance, provision shall be made for
the bubbling action of the air and the evaporation of the liquid, or it may be found
expedient to employ two or more liquids of different specific gravities, such as
mercury and water, (in which case the water will expand and freeze up the outlet,
whilst the mercury will remain liquid at or about the freezing point for water).
Dated this 15th day of September 1891.
COMPLETE SPECIFICATION.
Improvements in Thermostatic Apparatus for Controlling Air
Admission Valves.
I JAMES MCHARDY of Fairfax House Chiswick in the County of Middlesex
Scientific Expert 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 :--
Any material may be used in the construction of this said apparatus, provided
that, by its contraction or expansion it may so act upon suitable valves as to admit,
or arrest the passage of, air.
For example a rod may be so connected with a valve as to open it by its
expansion and close it by its contraction, consequently (the rod being regulated as
to its length by a suitable screwed joint, or its equivalent) cold air will be admitted
when temperature rises and shut off when it falls; or, if the object be to admit
hot air for heating purposes it will only be necessary to cause the rod through
expansion to arrest instead of admitting the hot air. As a matter of course one or
any number of rods may be used in any way combined or any mechanical combina-
tion may be employed to produce such variation in length as will work the valve
or valves; or any length of flexible material may be wound about pulleys so as to
give sufficient length without taking up great space.
A right and left thread or any equivalent may be used to regulate the length of
material to the working degree.
In cases in which it is possible to ascertain the exact bulk of a frozen mass that
will temper the atmosphere, mercury alone or in combination with any fluid or
liquid may be used in such a manner that it will in freezing shut off the supply of
cold air; or, as is manifest any liquid may be used for this purpose provided that
by its contraction or expansion it enables us to apply the principle.
If mercury be used it will be enclosed in a suitable vessel such as is shown in
the accompanying drawings and fully explained in the references thereto.
If any other liquid be used, such as water it will be confined in a vessel suitable
such as is also represented and fully explained by the drawings and references
thereto.
Or if an electric current be used to open or close a valve or to actuate any
thermostatic appliance the said circuit may be disconnected or completed by the
rising or falling of the thermometer with or without a float.
The accompanying drawings show how this invention may, in its simplest form,
be carried into practice.
Fig. 1-The thermostatic governor in which
A B-metal rods joined in one by means of a right and left nut, as suggested.
C-The end of said rod retained in a fixed position.
D-The loose end of said rod or rods hinged upon a lever-valve which is actuated
by the contraction or expansion of the said rod or rods.

page_text: D-the hinge connection,
E- -a fixed fulcrum-joint, and
G-the valve.
H-A pipe for the supply of hot or cold air.
If A B contract, D will be drawn in the direction of C, and F will be forced in
the direction of H, consequently the valve G will be closed.
This construction is applicable for the admission of cold air.
Now if we make D a fixed fulcrum and hinge A B at E, the opposite effect will
be procured; ie., the contraction of A B will open the valve G, and the apparatus
will be suitable for the admission of hot air. (N.B. The valve in this case may
require a spring to close it.) As hereinbefore mentioned, any mechanical com-
bination may be introduced to obtain sufficient play for the valve actuated by the
contraction and expansion of the material.
Fig. 2 The application of the mercury as hereinbefore suggested, in which ;
A-a float of such weight as shall draw down
B the valve, when the mercury falls, and so close
C-the exit.
F F The mercury contained within the vessel above outlined.
E-The tube for the supply of cold air, admitted at
D-the bottom of the vessel.
The dotted outline represents the float and its connection with the valve B. It
is here shown in the position for allowing the air to escape at C.
Now if the cold air enters at D and reduces the temperature of the mercury
until its falling brings B down upon C, the exit will be closed until the temperature
again rises. Such an appliance may be immersed in any sufficient quantity of
water and so adjusted as to keep it continually frozen or at any given degree.
Fig. III-A vessel which may be filled, say to the dotted line with water.
A The exit (for air).
D-The point at the bottom of the vessel A B C, at which the cold air is
admitted from
E-the pipe supplying compressed air.
The cold air passing through the water-(relieved from pressure by the free
exit)-freezes it. The water expands and gradually closes the exit at A, until
thawed, when the process repeats itself.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed I declare, that what I
claim is;
1. The application of the principle of contraction and expansion of metal or
other material to the regulation of air-admission valves, particularly as herein set
forth.
JAMES MC HARDY.