U.S. patent number 3,575,229 [Application Number 04/848,952] was granted by the patent office on 1971-04-20 for smoke seal for curtain-type fire dampers.
This patent grant is currently assigned to The American Warming & Ventilating Inc.. Invention is credited to Raymond L. Alley.
United States Patent |
3,575,229 |
Alley |
April 20, 1971 |
SMOKE SEAL FOR CURTAIN-TYPE FIRE DAMPERS
Abstract
A smoke seal for a curtain-type fire damper is provided. The
seal comprises two metal strips located adjacent the side frame
members of the fire damper, each being urged inwardly by a pair of
resilient strips therebehind. The extent of inward movement of the
strips is restricted by suitable stops located adjacent one
end-frame member of the fire damper. The strips contact the ends of
the fire damper blade sections when they are closed to provide an
effective smoke seal therebetween.
Inventors: |
Alley; Raymond L. (Toledo,
OH) |
Assignee: |
The American Warming &
Ventilating Inc. (Toledo, OH)
|
Family
ID: |
25304706 |
Appl.
No.: |
04/848,952 |
Filed: |
August 11, 1969 |
Current U.S.
Class: |
160/1; 454/369;
126/285R; 160/84.01 |
Current CPC
Class: |
A62C
2/16 (20130101) |
Current International
Class: |
A62C
2/00 (20060101); A62C 2/16 (20060101); E05f
015/20 () |
Field of
Search: |
;160/1--9,84
;49/419,414,74,90,91,371,480 ;98/114,86,1 ;126/285 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Williamowsky; David J.
Assistant Examiner: Kannan; Philip C.
Claims
I claim:
1. A fire damper comprising two side frame members and two end
frame members, a plurality of connected sequential blade sections,
an edge of one said blade sections being affixed to one of said end
frame members, means holding said blade sections in a retracted
position adjacent said one end frame member, a pair of spaced,
parallel vertical flanges on the inner side of each of said side
frame members and extending inwardly therefrom, the flanges of each
pair being spaced apart a distance greater than the width of said
blade section, a vertically extending blade edge sealing strip
positioned between each of said pairs of vertical flanges and
resiliently contacting the ends of said blade sections, and stop
means adjacent the other of said end frame members and engaging the
corresponding ends of said sealing strips for limiting the inward
movement thereof.
2. A fire damper according to claim 1 characterized further by said
stop means comprising two flanges extending outwardly from said
other end frame member.
3. A fire damper according to claim 1 characterized further by said
stop means comprising a pair of flanges extending outwardly from
said other end frame member and extending longitudinally thereof,
and a flat strip connecting said longitudinally extending flanges
and engageable by the last one of said blade sections when the fire
damper is closed.
4. A fire damper according to claim 1 in which the sealing strips
are flat and there are separate resilient means located between
said strips and the respective adjacent side frame members for
biasing said strips inwardly.
Description
This invention relates to a seal for a fire damper and particularly
to a smoke seal for a curtain-type fire damper.
The advisability of employing fire dampers particularly in
commercial buildings has been strengthened over recent years. As
more fire dampers are employed, the requirements or specifications
for such dampers have also been tightened. More recently, the need
to make such fire dampers smoketight for a reasonable period of
time to enable people to evacuate the endangered premises has
become more fully realized. Heretofore, seals have been proposed
for fire dampers but have not been satisfactory. Such seals have
been expensive and usually involved moving parts in the nature of
hinged members which are subject to becoming stiff and inoperative
over a period of nonuse. Consequently, where smoke seals have been
desired or required heretofore, it has been common to use a
conventional fire damper and add a separate smoke damper downstream
of the fire damper. The use of two dampers, of course, has been
expensive and, further, if the duct work between the two should
fail, then the smoke will bypass the smoke damper and render it
ineffective.
The present invention relates to a smoke seal in combination with a
fire damper of the curtain type and particularly having integral
blade sections normally held in a retracted position at one end of
the damper and movable thereacross when released to close the
damper. Such a damper is shown in a copending application of
Johnson and Alley, Ser. No. 660,449. The seal according to the
invention includes continuous, imperforate strips of metal located
adjacent the side frame members of the damper and preferably
between two spaced inwardly extending flanges thereof. A pair of
resilient strips are located between the metal strips and the side
frame members to urge the metal strips inwardly toward the opening
of the damper. The extent of movement inwardly is limited at the
one end of the damper by the retracted blades and stop means are
provided at the opposite end of the damper to limit the inward
movement of the metal strips at that end. The distance between the
metal strips at the latter end preferably is slightly less than the
length of the blade sections of the damper. With this arrangement,
the damper can close fully with all blade sections in contact with
the metal strips, yet without undue interference of the closing
action of the blades by the metal strips.
An effective and reliable, as well as low cost, seal is provided
with this arrangement. Further, the seal is effective at least
until the temperature thereof rises to 300.degree.--500.degree. F.
By this time, all occupants should have evacuated the building, at
which time the smoke seal is no longer important.
It is, therefore, a principal object of the invention to provide a
fire damper with a smoke seal having the advantages outlined
above.
Other objects and advantages of the invention will be apparent from
the following detailed description of a preferred embodiment
thereof, reference being made to the accompanying drawings, in
which:
FIG. 1 is a view in perspective of a fire damper embodying the
invention with portions of the frame shown in phantom;
FIG. 2 is a fragmentary view in transverse cross section taken
along the line 2-2 of FIG. 1;
FIG. 3 is a fragmentary view in cross section taken along the line
3-3 of FIG. 1, but with the blade sections in a closed
position;
FIG. 4 is a view in perspective of a portion of a side sealing
strip of the fire damper;
FIG. 5 is a view in perspective of a portion of a resilient strip
used with the sealing strip of FIG. 4 to urge the sealing strip
inwardly;
FIG. 6 is a fragmentary view in longitudinal cross section taken
along the line 6-6 of FIG. 1; and
FIG. 7 is a fragmentary view in cross section similar to FIG. 6 but
with the blade sections in the closed position.
Referring particularly to FIG. 1, a fire damper embodying the
invention is indicated at 10 and is shown in a horizontal position,
as when mounted in a vertical duct or in a ceiling of a building.
The fire damper 10 includes a frame 12 having side frame members 14
and 16, and end frame members 18 and 20. All four of the frame
members can have the same transverse cross-sectional shape,
including inwardly extending flanges 22 and 24 which act as guides
and also aid in sealing the damper, when closed.
The fire damper 10 also includes a metal sheet 26 which is curved
or folded in opposite directions at spaced, predetermined
intervals, as along folds or fold lines 28, to form adjacent
integral blade sections 30. One end edge of the sheet 26 is affixed
to the end frame member 18 by suitable fasteners. When the sheet is
in the retracted position, it is retained by suitable chains 32 and
angle members 34 which are connected by a fusible link 36 or any
other sensing device which is actuated by products of combustion.
With the sheet in the retracted position, the adjacent blade
sections 30 are in a stressed condition so that when the fusible
link 36 is parted, the blade sections spring quickly toward the end
frame member 20 to a closed position, as shown in FIGS. 3 and 7.
This closing action can be quite strong, due to the stressed
condition of the blades, with no additional springs or other
closing means being required, whether the damper is positioned
horizontally or vertically.
When the blade sections 30 are closed, an effective smoke seal is
established at the end frame member 18 since the end edge of the
sheet 26 is affixed to that frame member. Also, an effective smoke
seal is provided at the end frame member 20 by an end blade section
38 which is retained in position by gravity when the fire damper 10
is mounted in a vertical position or which can be retained in
position with the aid of latch members (not shown) as disclosed in
my copending application Ser. No. 819,243 when the fire damper is
mounted in a horizontal position.
The edges of the blade sections 30 adjacent the side frame members
14 and 16, however, do not normally provide as effective seals
since some clearance must be incorporated between the side frame
members and the edges of the blade sections 30. To overcome this
problem, metal sealing members 40 are provided for the side frame
members 14 and 16 between the inwardly extending flanges 22 and 24
thereof. Each of the sealing members 40 includes a flat metal strip
42 which extends longitudinally of the side frame members between
the end frame members 18 and 20. The strip 42 has two pair of
flanges 44 and 46 on the rear thereof which form grooves 48.
Resilient strips 50 have generally triangular-shaped tongues 52
which are received in the grooves 48 and held thereby. The strips
50 also have bulbous portions 54 which are sized such as to bear
against the side frame members 14 and 16 between the flanges 22 and
24 and urge the sealing strips 42 inwardly.
Various other resilient means can be employed in association with
the sealing strip 42. The resilient strips 50 function
satisfactorily, however, in urging the strips 42 inwardly as well
as in forming seals between the sealing members 40 and the side
frame members 14 and 16. While the resilient strips 50 may fail at
a temperature of 300.degree.--500.degree. F., by this time, the
building should long have been evacuated. Further, even with
failure of the strips, the fire damper is still effective to block
passage of flames thereby. If desired, however, resilient metal
strips can be employed for higher temperature resistance.
At the ends of the side frame members 14 and 16 toward the end
frame member 18, the extent of inward movement of the sealing
members 40 is limited by contact with the edges of the blade
sections 30. At the opposite end of the fire damper 10, near the
end frame member 20, stop means are positioned to limit the extent
of inward movement of the sealing strips. As shown in this
instance, the stop means are provided by U-shaped stop member 56
which is affixed to the end frame member 20. The stop member
includes a flat central portion 58 (FIG. 3) and two edge flanges 60
and 62. The flat central portion 58 provides a seat for the end
blade section 38 for sealing purposes and the edge flanges 60 and
62 space the flat portion 58 from the end frame member 20 so that
the stop member 56 engages end portions of the strips 42 and limits
the inward movement thereof. Consequently, the ends of the sealing
strips 42 toward the frame member 18 are retained in position by
the blade sections 30 and the stop member 56 retains the opposite
ends of the sealing strips 42.
As shown in FIGS. 6 and 7, the stop member 56 is of a length such
as to position the corresponding portions of the strips 42 apart a
distance slightly less than the length of the blade sections 30
across the fire damper. With this arrangement, the sealing strips
42 engage the edges of the blade sections 30 effectively, when
closed, yet do not extend inwardly enough to hamper the closing
movement of the blade sections 30. Tabs or various other stop means
can be employed adjacent the end frame member 20 to hold the
sealing strips in the aforesaid positions. Regardless of the type
of stop means employed, however, such means are important to enable
the fire damper 10 to operate with maximum efficiency and
reliability.
Various modifications of the above described embodiment of the
invention will be apparent to those skilled in the art and it is to
be understood that such modifications can be made without departing
from the scope of the invention, the embodiment shown and described
being primarily for purposes of illustration and not
limitation.
* * * * *