Improvements in Miners' Safety Lamps, particularly applicable for Trying or Testing for Explosive Gas.
Year: 1890

page_text: Date of Application, 19th May, 1890
Complete Specification Left, 19th Feb., 1891-Accepted, 28th Mar., 1891
PROVISIONAL SPECIFICATION.
Improvements in Miners' Safety Lamps, particularly applicable for
Trying or Testing for Explosive Gas.
I, ANDREW HOWAT, of 6, Bellwood Terrace, Old Trafford, in the County of
Lancaster, Engineer, do hereby declare the nature of this invention to be as
follows:-
My invention relates to certain improvements in miners' safety lamps and the
object of my invention is to make an improved form of safety lamp which, while
particularly applicable for use by the firemen employed for the purpose of trying or
testing the workings in mines for gas or explosive fluid mixtures, is also applicable.
for ordinary requirements.
In carrying my improvements into effect I prefer to employ a lamp substantially of
the construction described in the Specification to my Application for Letters Patent
No. 17410 of 1889 in which the wire gauze cylinder (or cylinders) is covered with
a metal shield or bonnet which rests upon the upper side of the deflector.
The deflector forms the roof of the air chamber, the bottom of which is formed
by the horizontal ring of the lamp frame, the outer side by a short cylinder, and
the inner side by a high collar or vertical ring, the ordinary air inlet being at or
near the bottom of the air chamber as set forth in my said Specification.
According to my present invention I provide an additional air inlet for gas testing
purposes by say three tubes the lower ends of which communicate with the top of
the air chamber and the upper ends preferably terminate in the top plate of the
lamp and are open to the atmosphere.
In the air chamber I fit a horizontal movable ring between the top of the high
collar or vertical ring and the underside of the top of the air chamber and below
this movable ring I pivot a forked lever or equivalent device which can be operated
from the outside of the lamp frame to raise and lower the said ring as required.
This ring is so fitted that when raised against the roof of the air chamber and
maintained in that position by a catch it closes the lower ends of the additional air
supply tubes and consequently all the air supplied to the burner has to enter the
lamp through the ordinary inlet at or near the bottom of the air chamber.
When the lamp is to be used for gas testing the catch is released and the ring
allowed to fall upon the top of the high collar or vertical ring thereby opening the
additional air supply tubes and closing the annular space in the air chamber above
the ordinary air inlet so that the air supplied to the flame is drawn from the top of
the lamp through the supply tubes and if any explosive gas is admitted with the air
its presence will be readily detected.
1
H. B. BARLOW,
Agent for Applicant.
COMPLETE SPECIFICATION.
Improvements in Miners' Safety Lamps, particularly applicable for
Trying or Testing for Explosive Gas.
1, ANDREW HOWAT, of 6, Bellwood Terrace, Old Trafford, in the County of
Lancaster, Engineer, 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 certain improvements in miners' safety lamps and the

page_text: object of my invention is to make an improved form of safety lamp which, while
particularly applicable for use by the firemen employed for the purpose of trying or
testing the workings in mines for gas or explosive fluid mixtures, is also applicable
for ordinary requirements.
In carrying my improvements into effect I prefer to employ a lamp substantially
of the construction described in the Specification to my Application for Letters
Patent No. 17410 of 1889 in which the wire gauze cylinder (or cylinders) is
covered with a metal shield or bonnet which rests upon the upper side of the
deflector.
And in order that my invention may be fully understood and readily carried into
effect I will describe the accompanying sheet of drawings reference being had to
the figures and letters marked thereon.
Figure 1 is a sectional elevation of a miners' safety lamp embodying my present
improvements.
Fig. 2 is a plan of the top of the lamp.
Fig. 3 a plan on the line A. B, and Fig. 4 a plan on the line CD, Fig 1.
Fig. 5 is a view of an alternative arrangement of the additional air inlet.
In these views a designates the top plate of the lamp, the metal shield or bonnet,
e the rods by which the top plate a is connected to the deflector d. The deflector d
forms the roof of the air chamber, the bottom of which is formed by the horizontal
ringe of the lamp frame, the outer side by a short cylinder f, and the inner side by
a high collar or vertical ring y, the ordinary air inlet e being at or near the bottom
of the air chamber as set forth in my said Specification.
According to my present invention I provide an additional air inlet for gas testing
purposes by say three tubes the lower ends of which are fixed in the deflector d
and communicate with the top of the air chamber and the upper ends preferably
terminate in the top plate a of the lamp and are open to the atmosphere; or as
shown in Fig. 5 the tubes may have side openings h¹ and the bonnet 6 have
corresponding openings through which the tubes are placed in communication
with the atmosphere.
In the air chamber I fit a horizontal movable ring i between the top of the high
collar or vertical ring g and the underside of the top of the air chamber and below
this movable ring i I pivot at a forked lever j or equivalent device which can be
operated from the outside of the lamp frame to raise and lower the said ring as
required by means of a wire k which can be engaged with a catch 1.
This ring i is so fitted that when raised against the roof d of the air chamber and
maintained in that position by the wire k and the catch it closes the lower ends of
the additional air supply tubes and consequently all the air supplied to the burner m
has to enter the lamp through the ordinary inlet e¹ at or near the bottom of the air
chamber before it passes through the gauze cylinders n.
When the lamp is to be used for gas testing the wire k is released from the catch
and the ring i allowed to fall upon the top of the high collar or vertical ring g
thereby opening the additional air supply tubes h and closing the annular space in
the air chamber above the ordinary air inlet e' so that the air supplied to the flame
is drawn from the top or upper part of the lamp through the supply tubes / and if
any explosive gas is admitted with the air its presence will be readily detected.
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. In a miners' safety lamp substantially of the construction specified, the com-
bination with the ordinary air inlet at or near the bottom of the air chamber, of an
additional inlet at or near the top of the lamp for supplying air to the upper part of
the air chamber, and means such as the movable ring i for opening and closing
either inlet as required.
2. The combination with the air chamber having the ordinary air inlets e¹ and

page_text: additional air inlets h, of the movable ring i and means for raising and lowering the
same when required all substantially as and for the purposes herein described and as
illustrated by the drawings annexed.
Dated this 18th day of February 1891.
H. B. BARLOW,
17, St. Ann's Square, Manchester, Agent for Applicant.