Improvements in or Applicable to Lamps, Lanterns, and other Apparatus for Producing Light.
Year: 1888

page_text: Date of Application, 9th May, 1888
Complete Specification Left, 8th Mar., 1889
Complete Specification Accepted, 4th May, 1889
PROVISIONAL SPECIFICATION.
Improvements in or Applicable to Lamps, Lanterns, and other
Apparatus for Producing Light.
I JOHN METHVEN of the Gas Light and Coke Company's Works, Nine Elms, in
the County of Surrey, Associate Member Institute Civil Engineers, do hereby declare
the nature of this invention to be as follows:-
My invention relates to improvements in or applicable to lamps, lanterns and other
5 apparatus for producing light.
In supplying the flaine of the lamp with air which has been artificially dried to
increase the illuminating power of the combustible material I have found that in order
to effect the desiccation of the air it is necessary to employ power to force the air
through the desiccating material.
1000
NEWTON & SON,
Agents for the Applicant.

page_text: Improvements in or Applicable to Lamps, Lanterns, and other
Apparatus for Producing Light.
I JOHN METHVEN, of the Gas Light and Coke Company's Works, Nine Elms, in
the County of Surrey, Associate Member Institute Civil Engineers 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 improvements in or applicable to lamps, lanterns, and
other apparatus for producing light.
The production of light in lamps, lanterns, and other apparatus from the combustion
of coal or other gas or vapour, or other suitable combustible materials, is greatly
improved by the use of dried air to support combustion.
The hygrometric state of the atmosphere varies, one may say, from hour to hour,
and the presence, under ordinary circumstances, of water vapour in the air which is
intended to support combustion, cools the flame, and reduces the photometric value
of the same.
This may be accounted for by the fact that much of the oxygen required to support
combustion is held in combination with the other constituents of the moisture, which
moisture, when it comes into contact with the flame, passes off as steam, without
having parted with its oxygen, leaving an insufficient supply of oxygen in the air which
accompanied it, to properly combine with, and consume the illuminating constituent,
viz., the carbon, thereby giving a comparatively smoky flame, and as a consequent
result, decreased development of light.
Now, when the air has been dried, the connecting or retaining link, viz.: the
moisture, between the constituent parts, say, the oxygen and nitrogen gases, is
removed; the constituent parts are released from cohesion, and the oxygen is free to
combine with the carbon of the gas, thereby raising the heat of the flame, and
producing practically perfect combustion, with considerable increase in the illuminating
power of the flame.
The amount of light given will be of constant power, as it will be independent of
the varying hygrometric conditions of the atmosphere, so that a light supplied with
the dry air is especially useful for photometric purposes.
In addition to the air, the combustible material may, if desired, be also dried, the
effect of which will be to further increase the illuminating power of the flame.
In order to effect the desiccation of the air, I employ power to force it over or
through the desiccating material.-The power may be derived from a small fan
driven at a high speed by a steam, gas, or other engine, or in any other convenient
manner. Or the air may be drawn through the material by a suitable pump. The
desiccating of the air may take place in an apparatus similar to a gas purifier,
viz. a rectangular vessel provided with a cover, and having removable perforated
trays, on which is laid the hygroscopic material. The air enters the vessel near
the bottom, and after passing through the desiccating material, escapes at the top.

page_text: Or, the trays to carry the desiccating material may be so arranged that the air
shall pass in a circuitous path over the material.-In this case, it is preferable
that the air shall enter at the top, and pass out at the bottom of the vessel.
The dried air may be conveyed direct to the lamp or other apparatus, or it may
be stored in bags or other suitable vessels, so that it shall not come into contact with
moisture.
The drying of the gas or other vapour may be effected by passing it through
similar apparatus.
Of the many hygroscopic materials which may be employed, I prefer to use quick
lime broken up into small pieces, and placed on the trays. Experiments have
demonstrated that one cubic foot of this material will suffice to remove the aqueous
vapour from about 50,000 cubic feet of air, and as coal gas requires, to induce proper
combustion, from 6 to 10 times its volume of air, according to the style of burner
used, it follows that one cubic foot of lime will dry air sufficient for the combustion
of from 5000 to 8000 cubic feet of gas.
The same quantity of lime will also serve to dry 50,000 cubic feet of gas or other
combustible vapour.
It will be obvious that the apparatus used for burning the illuminant must be so
arranged that the external undried air cannot come into contact with the flame. Thus,
supposing the apparatus to consist of an argand burner, the bottom of the chimney
will be hermetically sealed against the entrance of external air, and will be in
connection with a pipe for the supply of the artificially dried air.
This pipe I provide with a cock, so that the delivery of the air may be controlled
according to the barometrical and thermometrical conditions of the atmosphere for
the time being. The object of having this control for the desiccated air supply to
the flame, is, that a sufficient quantity of air may be always supplied to ensure
perfect combustion, and to prevent access to the flame of more air than is absolutely
necessary (according to the barometric and thermometric conditions) for that
purpose.
Flames produced by burners receiving an uncontrolled supply of air from the
atmosphere are more or less affected by every change in the barometer and
thermometer, hence the difficulty well known to practical men, of maintaining a
constant standard of light.
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 to apparatus for producing light from which the external air
is excluded, of a dried air supply obtained, by forcing air through or over quick lime
or other suitable desiccating material, as and for the purpose set forth.
2. Controlling the supply to lamps of air which has been dried by forcing it
through or over a desiccating material, whereby a constant standard of light is
obtained, irrespective of barometric and thermometric conditions, as set forth.
Dated this 7th day of March 1889.
NEWTON & SON,
Agents for the Applicant.