Improvements in Apparatus for Producing Electric Sparks.
Year: 1899

page_text: Date of Application, 14th Apr., 1899-Accepted, 27th May, 1899
[Communicated from abroad by ALBERT RICHARDSON SHATTUCK, of 11, Broadway,
New York, United States of America, Gentleman.]
Improvements in Apparatus for Producing Electric Sparks.
I, HENRY HARRIS LAKE, of the Firm of Haseltine, Lake & Co., Patent Agents,
45, Southampton Buildings, in the County of Middlesex, 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:-
The invention relates to the electric production of sparks for the ignition of gas or
inflammable vapor whether in gas engines, apparatus for lighting gas escaping
from burners and analogous devices, or for the firing of explosives in guns, mines
and torpedoes, or for any other purpose for which electric ignition may be usefully
employed. The accompanying drawing is an electrical diagram illustrating the
various parts and their relation symbolically.
Up to the present time the only practicable means of producing an electric
spark of such power and efficiency as to be capable of igniting, for example, the
explosive mixture of air and gas in a gas engine at predetermined intervals has
been an induction coil having in its circuit a rapidly acting automatic circuit
breaker or buzzer" and also a simple circuit closer, switch or commutator, which
being actuated at predetermined intervals set the buzzer" in operation. It has
hitherto been regarded as practically established that such a make and break in the
circuit as would ordinarily be caused by the last mentioned circuit closer, switch
or commutator alone, will not produce a spark of sufficient intensity to insure
proper ignition. Or, in other words, leaving out of consideration the application
of the induction coil specifically to a gas engine, and referring to the matter
therefore broadly, it has hitherto been regarded as well settled that with an
induction coil of given proportions and a source of current of given power, it is not
possible to produce a spark of as high intensity without the buzzer in con-
junction with the circuit closer as with it. On the other hand, it is also well known
that the presence of the "buzzer" is objectionable for several reasons, among which
may be mentioned rapid oxidation and burning of its contacts, waste of current
energy thereat, and its rapid deterioration, so that the apparatus might become
inefficient in its working at any instant which could not be foreseen. This un-
certainty may especially occur in circumstances where by reason of the construction
of the particular device in which the igniting apparatus is embodied the
buzzer"
may be enclosed, and hence not under immediate observation. As a consequence
the effective lifetime of the apparatus rests upon the continued integrity of the
buzzer" rather than upon that of the other associated parts.
"
*
In cases of the application of the electric spark to the firing of guns, mines
and torpedoes it is especially important that this cause of possible failure should
be removed.
By the present invention powerful and efficient sparks adequate to any purpose
of electric ignition as now practiced in the arts is produced by means of an induction

page_text: coil having in the circuit a simple make and break circuit closer, switch or
commutator. To this end the induction coil is constructed so that the secondary
thereof is placed in shunt relation to the primary and the spark terminals are
arranged in the secondary circuit. It is preferred also to arrange the circuit
breaker in such a way as that a single rapid break is produced after a relatively
long period of closure; this period being sufficiently long to enable the current to
reach its full value before the rupture determining the spark is made.
Referring to the drawing, A represents the primary circuit in which is the source
of electricity B and the primary coil C. Included in said primary circuit is a
circuit breaker, which may consist of a fixed contact D and a spring contact E,
normally separated. Acting on the spring contact E is a cam F' on a rotary shaft G,
which shaft may be rotated by the pulley and belt H. At every rotation of the
cam G the spring E is brought into contact with the plate D, thus closing the
circuit. Or, in other words, the circuit is made and broken at each rotation of the
cam G.
The secondary circuit I includes the secondary coil J and the terminals K and L,
between which is the gap over which the spark passes. The terminals of the
secondary circuit are shown as connected to the primary circuit at M and N, so that
the primary and secondary coils are therefore in shunt relation. It is not essential
that the connection should be made at the precise points M and N, but the primary
and secondary, coils may be connected at any point so long as the shunt relation
stated is preserved.
When the primary and secondary coils are thus connected, a mechanical breaker
such as described interrupting the current with comparative infrequency becomes
fully as efficacious as the well known rapidly working electrical buzzer commonly
employed in induction coils. Not only by eliminating the buzzer or quick working
electrical breaker is the rapid oxidation and burning of contacts, and waste of
current energy at the buzzer obviated, but by making a single rapid break in the
primary after a period of closed circuit sufficiently long to enable the current to
reach its full value, there is produced an extended and very powerful and hence
very effective igniting spark. A condenser may be connected in circuit with this
spark coil in the usual manner.
Having now fully described and ascertained the nature of the said invention and
in what manner the same is to be performed, as communicated to me by my foreign
correspondent, I declare that I claim is:-
1. In an electric spark producing apparatus, the combination of a primary coil
and circuit breaker in circuit therewith, and in shunt with said primary coil and in
inductive relation thereto, a secondary coil, and spark terminals included in the
circuit thereof, substantially as described.
Dated this 14th day of Aari 189999I
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.