Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
This invention relates to a flare stack igniter and in part-
ocular to a remote control flare stack igniter and is a division of co-
pending Canadian Patent Application Serial Number 413,042-1 filed on
October 7, 1982 entitled "FLARE STACK IGNITER".
Igniters for so-called flare or vent stacks must ensure
ignition and maintain combustion of gases emitted from the stacks. More-
over it should be a simple matter to install and service such igniters.
Flare stack igniters are disclosed by U. S. Patent Number 3,797,991 issued
to J. F. Strait III on March 19, 1974; Number 3,833,336 issued to Al. L. Ray
on September 3, 1974 and Number 4,147,498 issued to R. R. Clarke on April 3,
1979. The igniters disclosed by these patents are permanently installed on
flare stacks and thus maintenance is unnecessarily complicated. In order
to service the igniter, disassembly of the stack or, alternatively, a
climb to the top of the stack is required.
An object of the present invention is to provide an electrode
structure for use in a flare stack igniter which ensures ignition of gas
even under adverse conditions.
Accordingly, the present invention relates to a probe for use
in a flare stack igniter of the type including a source of electrical
power for causing arcing between a pair of probes whereby any combustible
gas passing between said probes is ignited, said probe comprising an eon-
grated, hollow, electrically conductive body for conducting electric current,
said body including an inlet end for admitting air into the body and a disk
charge end for discharging air into the gas whereby the flow of said gas
draws air through the body for promoting combustion of said gas.
I
The invention will now be described in greater detail with
reference to the accompanying drawings which illustrate a preferred
embodiment of the invention and wherein;
Figure 1 is a side elevation view of a flare stack igniter
in accordance with the present invention;
Figure 2 is a front elevation view of the main elements of
the igniter of Figure it
Figure 3 is a perspective view from below of the probe struck
lure used in the device of Figures 1 and 2;
Figure 4 is a perspective view from below of the probe struck
lure of Figure 3 in the igniting position;
Figure 5 is a perspective view of the probes of the apparatus
of Figures 1 to I; and
Figure 6 is a partly sectioned front elevation view of a
braking system for use with the igniter of Figures 1 to 5.
With reference to the drawings, the flare stack igniter of
the present invention is intended for use on a tubular flare stack 1
of the type normally used to discharge sour gas from a well (not shown).
The flare stack is maintained in the vertical position by guy wires 2
(Figure) the top ends of which are connected to eyes 3 extending out-
warmly from a sleeve 4 on the stack 1 and the bottom ends of which are
connected to ground anchors (not shown). Sour gas is discharged from
the top end 5 of the stack 1 and is ignited by the igniter of the
present invention.
The igniter of the present invention can be permanently
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installed on new stacks during installation or, alternatively, added
to an existing stack. The nutria includes a pair of parallel tracks
6 extending upwardly from close to the ground 7 to close to the top 5
of the stack 1. The tracks 6 are connected to the stack by generally
U-shaped arms 8 which are integral with the tracks 6 and U-bolts 9
which connect the arms 8 to the stack 1. The bolts 9 are insulated
from the stack 1 by means of non-conductive sleeves 10. The tracks
6 have a generally U-shaped cross section, the open sides thereof
opposing each other, i.e. facing inwardly. As best shown in Figures
1 and 4, the upper ends 11 of the tracks 6 are bent inwardly towards
the stack 1 and a stop plate 12 is provided at the top end of each
track.
The tracks 6 movably support a pair of carriages, generally
indicated at 13 and 14. The uppermost carriage 13 is defined by a
rectangular frame 15. A pair of stub axles 16 extend outwardly from
each side 17 of the frame 15 for supporting discs 18. The use of discs
18 rather than rollers reduces maintenance of the igniter, since there
are no bearings to corrode. The discs 18 ride in the tracks 6. The
spacing between the tracks 6 is only slightly greater than the width
of the frame 14 so thaw, once inserted from the bottom end the frame
15 is retained between the tracks. Four posts 19 extend outwardly
from the sides 17 of the frame 15 (when the trolley is in the vertical
position). Bell-shaped insulators 20 are mounted on the outer ends of
the posts 19. The insulators 20 are high voltage, high gloss insulators
which prevent shorting out because of carbon build-up or possible oil
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splash. The insulators 20 support a pair of elongated probe supports
21. The probe supports are parallel to each other and parallel to the
sides 16 of the trolley frame 15. The probe supports have a generally
U-shaped cross sectional con-figuration. A probe 22 is mounted in each
of the supports 21. The probe 22 which may be in solid bar form or
hollow tube, us held on the support by a plurality of U-bolts 23~
With reference to Figure 5, in the preferred form of the
invention, each of the probes 22 is defined by an elongated electrically
conductive hollow metal body with a straight bottom end for mounting in
the support 21 and on inclined upper end, such that when in use the
upper ends 24 of the probes 22 above the support 21 curve inwardly to-
wards the plane of the trolley 13 and towards each other, so that there
is only a small gap between the upper ends 24 of the probes 22. As can
be seen the upper ends, or tips of each probe, are angularly sectioned
such that each tip presents in close proximity one to the other a
relatively large air discharge opening and, of course, an elongated
elliptical arcing surface.
The first and second trolleys 13 and 14 are inter-connected
by means of cables 26. Each cable 26 extends between an eye 37 on the
bottom end of the trolley 13 and eye 28 on the top end of the trolley
14. Like the trolley 13 the trolley 14 is defined by a rectangular
frame 29. A pair of discs 20 is provided on each side 31 of the frame
29 for riding in the tracks 6.
A transformer 33 is mounted on the second trolley 14. flea-
tribal power is fed to the transformer 33 from a source of power (not
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shown) through a cable 34. A pair of insulators 35 are mounted on posts
36 on the trolley 14 above the transformer 33. Power from the transformer
33 is fed through leads 37 to the probes 22 to cause arcing between the
top ends of such probes
The trolleys 13 and 14 are caused to move up the tracks 6 by
a manually operated winch 38 (Figure 1) which is mounted on the stack 1
beneath the tracks 6. A pair of U-bolts 39 hold the winch body on the
stack 1. A cable 40 from the winch drum 41 extends upwardly around a
pulley 42 mounted on the stack 1 near the top end thereof. The upper
end of the cable 40 is connected by an eye bolt 43 to the frame 15 of
the trolley 13. Thus, when the winch 38 is operated the trolleys 13
and 14 are caused to move upwardly on the stack 1.
While it is not essential to provide a brake for the trolleys
13 and 14 a brake can be provided to prevent damage to the apparatus
caused by winch failure. A suitable brake is illustrated in Figure 6.
The brake includes a pair of arms 45 which are pivotal connected to a
plate 46 extending downwardly from the bottom of the frame 15 for rota-
tion around a horizontal axis 47. For strength the plate 46 extends
from the top to beyond the bottom of the frame 15. The arms 45 are
connected to the plate scissors fashion, i.e. the arms cross each other.
One end of each of a pair of cables 48 is connected to the cable 40 and
the other end of each cable 48 is connected to one of the arms 45 above
the axis 47. Thus, when the cables 40 and 48 are taut during upward
movement or locking of the winch 38~ the top ends 50 of the arms 45
press against the bottom of the frame 14 to lift or hold the trolley 13.
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If the cable I breaks or the winch 38 fails, the arms 45 rotate around
the axis 47 so that the bottom ends 51 of such arms bear against the
bight of the tracks 6. By providing a brake shoe (not shown) on the
bottom end 51 of each arm I braking is improved. Of course, if the
trolley I is lowered slowly and under control, tension is maintained on
the cables I and 48 and consequently on the arms 45, to prevent braking.
In operation with the trolleys 13 and 14 in the lower position
the winch 38 is actuated to move the trolleys up the tracks 6. Upon
reaching the top of the tracks 6 the top end of the trolley 13 moves
inwardly to position the top ends of the hollow probes 22 substantially
centrally over the discharge end of the flare stack 1. High pressure
gases exiting From the discharge end of the stack 1 create what can
be loosely termed a venturi effect around the tips or discharge ends of
probes 22, drawing fresh air and hence oxygen through the lower and open
inlet ends of the hollow probes 22 to be admixed with the stack gases in
the immediate area of the probe tips. Current is then passed through the
transformer 33 and the leads 37 to the probes 22 to cause arcing between
the arcing surfaces of the probes in the area enriched by the educed
supply of fresh air. Such arcing is normally intermittent, i.e. every
thirty seconds, to ensure ignition of gases. The power source may
comprise 12 volt batteries or in cases where timed ignition is not
required, power can be drawn from any external source, for example the
operator's truck battery.
It will be appreciated that the use of tracks extending the
length of the stack reduces maintenance costs. The probes or electrodes
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can be lowered for cleaning. Thus the usual gin pole truck or crane
and man basket are unnecessary. It is also unnecessary to lay down the
stack or igniter or to shut in the well.
Because the hollow probes serve to supply a continuous flow
of fresh air and are preferably of stainless steel, an arc can be main-
twined in adverse weather or sour gas conditions; carbon build-up is
greatly reduced and the probes are less susceptible to burn-off.
Further modifications and alternative embodiments of the
invention will be apparent to those skilled in the art, in view of the
foregoing description. Accordingly this description is to be construed
as illustrative only and is for the purpose of teaching those skilled
in the art the manner of carrying out the invention. It is further
understood that the form of the invention herewith shown and described
is to be taken as the currently preferred embodiment. Various changes
may be made in the shape, size and general arrangement of components,
for example, equivalent elements may be substituted for those thus-
treated and described herein; parts may be used independently of the
use of other features, all as will be apparent to one skilled in the
art, after having the benefits of the description of the invention.
