Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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FIELD OF INVENTION
This invention relates to improvements in fire
detectors and structural components therefore
BACKGROUND OF INVENTION
Fire detector devices may be designed to actuate
an alarm by closing or opening a circuit on the happening
of either one, or both, of two events -- when the rate
of rise of the temperature of the ambient atmosphere exceeds
a predetermined prescribed standard, for example, they'll F
per minute standard set by Underwriter Laboratories Inc.
of the United States, and/or when the ambient temperature
exceeds a predetermined fixed temperature.
These detectors must also operate in all environmental
conditions, for example, extremes of humidity, variations
of heat and cold, and acidic or alkaline vapor mediums.
The necessity for such operation has been recognized
by various governmental and independent examining bodies,
and standards have been set which the devices must meet
or exceed. One such body is the Fire Insurers' Research
and Testing Organization (FORT for short) of the United
Kingdom, which as part of its testing program, has prescribed
that such fire detectors must pass a sulfuric acid environment
test. This test requires that the fire detector sit in
a sulfuric acid environment for a predetermined time and
thereafter, still be operable. however, no fire detector
that was vented to atmosphere tested with the rate of rise
feature before my detector disclosed in Canadian Patent
Application Serial Number 336,801 has remained operable
after the time period spent in the sulfuric acid vapor
medium. The reason lies in the construction of the vented
detector incorporating the rate of rise feature. The chambers
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1 between the shell and the diaphragm and diaphragm and base,
must be vented to atmosphere to permit normal atmospheric
expansion and contraction due to temperature fluctuations
without actuating the alarm. however, if any of the vent
apertures are left unprotected in the acidic environment
(especially the vent aperture opening from the space between
the diaphragm and base) the acidic environment is drawn
into the chambers when the detector is "breathing" during
normal temperature fluctuations, thus corroding the electrical
contacts in the spaces.
In Canadian Patent application Serial Number
336,~0l I have disclosed an improved fire detector vented
to atmosphere, capable of closing or opening an alarm circuit
when the rate of rise of the temperature of the ambient
atmosphere exceeds a predetermined prescribed rate of rise
of temperature comprising a base supporting a diaphragm
enclosing a space between the base and diaphragm, a shell
secured to the base enclosing a space between the diaphragm
and shell, electrical circuit contacts mounted on the base
for being closed or opened when the actual rate of rise
of temperature of the atmosphere in the space between the
diaphragm and shell exceeds a predetermined rate of rise
of temperature, vent apertures through the base from the
spaces between the diaphragm and shell, and the diaphragm
and base, to the back of the detector, the improvement
comprising the vent apertures each being surrounded by
an endless wall covered by a closure cap having a top and
depending skirt, small projections disposed between the
top of the closure cap and the top of the endless wall
I and thin posts or lugs between the endless wall and depending
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1 skirt for spacing the top of the wall from the top of the
closure cap and spacing the endless wall from the depending
skirt to cover the vent aperture permitting the spaces
between the diaphragm and base, and shell and base, to
be vented to the atmosphere under normal expansion and
contraction of the ambient atmosphere in the fire detector
without drawing substantial amounts of air from outside
the cover and wall through the vent apertures.
While this proposal went a long way to overcome
the problems herein before referred to, nevertheless, small
amounts of dust material have from time to time entered
the vent aperture.
Detectors of the type described usually carry
a heat collecting fin outside the shell and are connected
to the shell by a ferrule. The ferrule also carries a
fusible link to a detent member within the shell. When
heat reaches the fin the heat is transferred from the fin
through the ferrule to the fusible link. It is therefore
preferable to provide the heat collecting fin with as large
a surface area as possible for maximum heat collection.
Where the fin and furler combined in one piece, the
fin could not be manufactured of sufficiently large enough
diameter at reasonable cost. Where attempts have been
made to make the fin-ferrule combination from two components,
as was done prior to my invention disclosed in my co-pending
Application Serial Number 336,801 with the fin of large
diameter, the union has not yielded a satisfactory result.
In my co-pending Application Serial Number 336,801,
I disclosed an improved fire detector having alarm actuating
means for actuating an alarm at a predetermined temperature
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1 and a fin for collecting heat from the ambient atmosphere,
the fin being connected by a ferrule to the alarm actuating
means for actuating the alarm at the predetermined temperature,
the connection between the fin and the ferrule having been
formed by causing metal in an end portion of the ferrule
to flow over fin metal surrounding the aperture of the
fin through which aperture the ferrule extends to provide
a thin layer of ferrule metal over fin metal.
As a result, the metal of the ferrule was married
to the metal of the fin. In that way, an anodized aluminum
fin of relatively large diameter (and thus non-solderable,
but immune to sulfuric acid) could be intimately connected
to a solder able blind hole tin plated aluminum ferrule.
However, it has been found that in some instances
during the marrying of the fin to the ferrule, the pressure
to hold the fin to the ferrule while ferrule material was
caused to flow radially over the fin material, distorted
the fin and in some of those instances, the pressure applied
in one area caused the connection of the fin to the ferrule
to buckle and loosen in another area.
It is therefore an object of this invention to
provide an improved fire detector and structural components
useful therefore
Further and other objects of the invention will
be realized by those skilled in the art from the following
summary of the invention and detailed description of embodiments
thereof.
SUMMERY OF THE INVENTION
Unexpectedly, according to one aspect of the
invention, an improved fire detector vented to atmosphere,
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1 capable of closing or opening an alarm circuit when the
rate of rise of the temperature of the ambient atmosphere
exceeds a predetermined prescribed rate of rise of temperature
is provided comprising a base supporting a diaphragm enclosing
a space between the base and diaphragm, a shell secured
to the base enclosing a space between the diaphragm and
shell, electrical circuit contacts mounted on the base
in the space between the diaphragm and shell for being
closed or opened when the rate of rise of the temperature
of the atmosphere exceeds a predetermined rate of rise
of temperature, at least one vent aperture through the
base Eros the space between the diaphragm and base to the
back of the detector, and at least one vent aperture through
the base from the space between the base and shell to the
back of the detector, the at least one vent aperture through
the base between the diaphragm and base to the back of
the detector being surrounded by an endless wall covered
by a closure cap having a top and depending skirt, the
closure cap spaced from the endless wall by relatively
small projections between the top of the closure cap and
the top of the endless wall and by relatively thin posts
or lugs between the endless wall and depending skirt for
spacing the endless wall from the depending skirt, (preferably
the wall including the relatively small projections on
the top of the endless wall and the relatively thin posts
or lugs extending from the side of the wall, to enable
the closure cap to snugly seat (on the small projections
on the top of the endless wall and against the outer surface
of the thin posts or lugs) the depending skirt being such
as to extend to a position above (preferably just above)
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isle
1 the bottom of the endless wall remote the top of the endless
wall whereby the atmosphere between the diaphragm and base
is permitted to expand into the space between the endless
wall and skirt which in turn forces air therefrom into
the space at the back of the detector under normal expansion
of the ambient atmosphere and draws air into the vent aperture
substantially only from the space between the endless wall
and skirt under normal contraction of the ambient atmosphere
between the diaphragm and base thereby precluding dust
and other contaminants in the space at the back of the
detector from entering the vent aperture. In one embodiment
the at least one vent aperture through the base from the
space between the base and shell its similarly covered.
According to another aspect of the invention,
an improved fire detector is provided comprising a base,
a shell secured to the base, a fin secured to the shell
by a ferrule passing through the shell at one end and secured
to a detent member carried in the shell by a fusible link
and at the other end by the ferrule passing through a centrally
disposed aperture through the fin, the improvement comprising
the fin being connected to the ferrule by causing substantially
equally spaced peripheral portions of the ferrule at the
end of the ferrule passing through the centrally disposed
aperture, to be indented to cause metal from such portions
to be forced to flow substantially radially over portions
of the fin surrounding the aperture in the fin, as for
example, by swaying whereby the outer surface of the ferrule
engages fin metal surrounding the aperture and metal forced
to flow radially from the peripheral indented portions
overlies and enrages the fin to provide a joint between
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1 the two which permits efficient heat transfer between the
two.
Preferably, the substantially equally spaced
peripheral portions are forced to flow substantially radially
over the portions of the fin substantially simultaneously.
In one embodiment, circumferential equally
spaced portions totaling about one-third of the peripheral
portion of the ferrule are swayed to flow over portions
of the fin metal surrounding the aperture in the fin.
In various such embodiments, the side wall of
the ferrule proximate the end of the ferrule passing through
the genially disposed aperture may be angled about 5 degrees
to the longitudinal axis of the ferrule tapering from the
end remote the fin towards the end proximate the fin.
according to another aspect of the invention,
an improved fire detector is provided having alarm actuating
means for actuating an alarm at a predetermined temperature
and a fin for collecting heat from the ambient atmosphere,
the improvement comprising an improved union between the
fin and ferrule, the fin having a centrally disposed aperture
there through for receiving the ferrule and, being connected
by the ferrule to alarm actuating means for actuating an
alarm at a predetermined temperature, the improved connection
between the fin and ferrule having been formed by swaying
equally spaced peripheral end portions of the ferrule totaling
about one-third of the periphery at the end of the ferrule
to be indented to cause ferrule material to flow radially
over fin metal surrounding the aperture in the fin whereby
the outer surface of the ferrule engages the fin metal
surrounding the aperture and metal forced to flow radially
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1 from the peripheral indented portions overlies and engages
the fin to provide a joint between -the two which permits
efficient heat transfer between the two.
Preferably, the substantially equally spaced
peripheral end portions of the ferrule are caused to substantially
simultaneously flow radially over fin metal surrounding
the aperture.
For best union, the side wall proximate the end
of the ferrule secured to the fin is tapered (preferably
at an angle of about 5 degrees to the longitudinal axis
of the ferrule) away from the other end of the ferrule
remote the fin.
Preferably, the aperture through the fin, through
which the ferrule is passed is only slightly larger than
the end of the ferrule to provide a tight fit there between
as the ferrule is pushed into the aperture to cause the
tapered ferrule to engage fin material to cause a tight
fit there between.
According to another aspect of the invention,
the equally spaced peripheral end portions of the ferrule
caused to flow radially over the fin may each be triangular
in shape, with the apex of each triangular portion spaced
from the periphery and with the broadest portion of the
triangular portion being remote the apex and overlying
the fin.
Preferably, the equally space peripheral end
portions of the ferrule are caused to flow over the fin
metal at substantially the same time.
As a result, the required ferrule and fin connection
is achieved minimizing distortion and minimizing crushing,
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1 of the components during the union of the fin and ferrule.
The invention will now be illustrated with reference
to the following drawings of an embodiment of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a perspective view of a fire detector
operating to actuate an alarm, when the rate of rise of
the temperature of the ambient air exceeds a predetermined
prescribed rate and, when the ambient temperature exceeds
a predetermined fixed temperature, according to a preferred
embodiment of the invention.
Figure 2 is a top perspective view of the fire
detector of Figure 1.
Figure 3 is a cross-sectional view of the fire
detector shown in Figures 1 and 2.
Figure 4 is an exploded view of part of the detector
shown in Figures 1 and 2.
Figure 5 is a vertical cross-sectional side view
of part of the detector shown in Figures 1, 2, 3 and 4.
Figure 6 is a close-up view of part of the structure
I shown in Figure 5.
Figure 7 is a close-up view of the union between
fin and ferrule of the detector shown in Figure 1.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION
With reference to Figure 1, there is shown a
fire detector 10, comprising base 12, and outer cup-shaped
shell 13 carrying annular heat collecting fin 14. Fin
14 is corrugated having spaced concentric annular ridges
15 (see Figure 6). Fin 14 is positioned with respect to
shell 13 by tin-plated aluminum ferrule 16 (see Figure
4) extending through central aperture AYE through the center
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1 of shell 13.
Ferrule 16 supports detent member 17 (see Figure
3) in blind bore 18 of ferrule 16 by fusible link 19. Detent
member 17 supports tapered compression spring 20, tapering
in a direction away from fin 14, and being compressed between
flange 21 on the end of detent member 17, and gasket AYE
adjacent shell 13 until fusible link 19 fuses.
Diaphragm 22 (see Figure 3) is stretched over
annular wall 23 of base 12 into annular trough 24 and held
there by a gasket 25 (sealed therein by epoxy) for dividing
the space between shell 13 and base 12 into two compartments
26 and 27. Compartment 26 houses contacts 28 for closing
the circuit on the happening of a hazardous situation. Calibrated
vent 29 leads from compartment 27 to the back of base 12
and permits predetermined amounts ox air to pass there through
under normal conditions of expansion and contraction of
air within compartment 27. Compartment 26 vents through
aperture 30. On the other side of base 12 are electrical
contact screws 31 and 32, opening 33 for vent 2g surrounded
by annular wall 34, and an opening for aperture 30, surrounded
by annular wall 35. Vent 29 and aperture 30 are covered
by closure caps 36 and 37 respectively. Spacer projections
38, i/32" (about 8/19 mm.) high are disposed on the top
of annular walls 34 and US on which the caps 36 and 37
I seat respectively. Each cap 36 and 37 is slightly larger
by the radial thicknesses of the thin post or lugs AYE
secured to the sides of annular walls 34 and US to snugly
secure the caps to the wall. Each lug or post is of a
circumferential length of about 3/32" (24 my Therefore,
continuous communication is permitted through the openings
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1 between the lugs and posts from the back of the detector
to the vent apertures. whereas the length of skirt AYE
of cap 36 is short, the length of skirt AYE of cap 37 is
much longer extending parallel to wall 35 to just about
the bottom AYE of wall 35 leaving an annular air space
or opening 35B between the cap 37 and wall 35 when cap
37 is snugly seated on wall 35 thus permitting communication
of vent aperture 30 with the space at the back of the detector
whereby the atmosphere between the diaphragm 22 and base
12 is permitted to expand into the space between endless
wall 35 and skirt AYE which in turn forces air therefrom
into the space at the back of the detector lo under normal
expansion of the ambient atmosphere and draws air into
the vent aperture 30 substantially only from the space
between endless wall 35 and skirt AYE under normal contraction
of the ambient atmosphere between diaphragm 22 and base
12 to ensure contaminants are precluded from entering the
vent aperture from the back of the detector. Vent aperture
29 could have been covered in a similar manner.
With particular reference to Figures 1, 3, 4,
5, 6 and 7, corrugated anodized aluminum fin 14 carrying
spaced concentric annular ridges 15, is secured to shell
13 by tin plate ferrule 16 extending through central aperture
AYE in the center of shell 13 and curled over or swayed
25 over the inside edge AYE (see Figure 4) of shell 13 surrounding
aperture AYE (see Figure 5) (after annular resilient tubular
member 42 carrying radial flange AYE has been interposed
between ferrule 16 and shell 13. Ferrule 16 is pressure
fit through aperture AYE of fin 14 in intimate contact
with the annular wall 14B surrounding aperture AYE. Radial
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flange AYE seats on flange 16D of ferrule 16 for sealing
opening AYE and compartment 27.
Ferrule 16 supports detent member 17 in blind
bore 16B by fusible link 19. Ferrule 16 comprises bottom
horizontally extending face 16C, tapered annular side wall
EYE tapering towards face 16C at an angle of 5 degrees
to the longitudinal axis of the ferrule normal to face
16C from radially extending flange 16D (see Figures 3 and
6).
furl 16 has been united or pinned to fin 14
by causing equally spaced circumferential or peripheral
portions of the end of ferrule 16 (face 16C) totaling
about 1/3 (one-third) of the peripheral portion of the
end of ferrule 16 to be forced to be indented to cause
metal from such portions to flow radially over fin 14 proximate
aperture AYE (see Figure 1 and 6 and particularly, Figure
7) at substantially the same time.
By this union, heat conduction from fin 14 to
the ferrule is maximized and the union between fin 14 and
ferrule 16 is accomplished without distorting fin 14 or
causing one area of the joint or union to buckle or loosen.
The union may be accomplished by a punch having a face
the negative of the impression left on the end of ferrule
16 on face 16C (see Figure 7), after having applied the
punch vertically for simultaneously causing equally spaced
peripheral portions of the end of ferrule 16 to be indented
to cause metal from such portions to flow radially over
fin 14 proximate aperture AYE, towards the periphery of
fin 14 while supporting fin 14 and ferrule 16 against movement
to thereby provide a more secure joint which permits efficient
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1 heat transfer.
As many changes can be made to construction of
the embodiment of the invention without departing from
the scope of the invention, it is intended that all material
contained herein be interpreted as illustrative of the
invention and not in a limiting sense.
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