Note: Descriptions are shown in the official language in which they were submitted.
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RADIANT TUBE AND REFLECTOR HANGER
Introduction
This invention relates to low intensity,
infrared radiant heating systems of the type in which
the infrared emitter is a metal tube which is charged
with hot gaseous effluent by means of a fuel-fired
burner. More particularly, the invention relates to
improved support and hanger means for radiant energy
heating systems which include tube type emitters and
reflectors used in combination.
Eackqround of the Invention
Low intensity, infrared radiant heating
systems are preferred over forced air and hot water
systems, for example, in many applications. This
preference is due in large part to the fact that radiant
heating involves direct energy conversions building mass
(concrete floors, machinery, et cetera), persons, plants
and animals in the heated areas receive sensible heat
via direct energy absorption rather than through the
movement of air which has been heated. As a result,
people can work comfortably in areas where the actual
air temperature is lower than that required for comfort
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in forced air and convection systems~ this, of course,
gives rise to substantial energy savings. In addition,
a concrete floor under an infrared emitter will absorb
energy in the range of frequencies characteristic of
radiant tube systems and will thereafter release thermal
energy through reradiation to make the enclosure more
comfortable for its inhabitants on an economical basis.
Such reradiation from the floor warms the feet of the
persons working or living in the effected area not only
during heating system operation but more importantly
afterwards, as well. Infrared systems have the further
advantage in greenhouses and the like by positively
effecting plant growth rate.
Low intensity infrared systems have further
advantages in high directionality capabilities
obtainable through the use of reflectors which aim the
radiant energy where it is needed the most, thus
increasing the effective utilization of the available
energy.
A fuel-fired, low intensity radiant energy
heating system typically includes a metal tube infrared
emitter, the tube being charged with hot gaseous
effluent by means of a fuel-fired heated. The system
is usually installed with the emitter tube positioned 7
to 50 feet above floor level. Reflectors in the form of
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light gauge metal fabrications or stampings are
installed immediately above the emitter tube over
substantially the entire operating length thereof to
direct the emitted radiation toward the floor.
Typically the entire structure, including the tube, is
held together by means of an alloy steel wire hanger
which is bent to provide seats for receiving the
opposite edges of the reflector. The center portion of
the hanger is curved to receive the tube. Wire hangers
are placed at regularly spaced intervals along the
longitudinal run of the reflector assembly. The alloy
steel wire hangers are then connected at their top
portions to an overhead structure, such as a ceiling
beam or other support, by a chain fastened to the
support and, in turn, fastened to the hanger. The alloy
steel wire hanger is, essentially, custom bent,
resulting in non-uniformity among hangers and increased
cost of manufacture.
Convection currents caused by temperature
differences along the length of the emitter tube and
disturbances within the enclosure actually scrub heat
off the emitter tube as the convection current flows
from the burner end of the emitter tube to the effluent
discharge end.. This convection current allows heat to
flow along the length of the tube until it reaches the
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end of the tube where the heat is discharged. This flow
of heat along the tube results in a loss of directable
radiant heat energy in the needed areas; requiring an
increased output by the burner to compensate for the
loss. Therefore if the amount of convected heat loss
can be reduced, the fuel savings is increased, thus
decreasing the operating cost of the system during
operation.
Summary of the Invention
The present invention is directed to
overcoming the disadvantages of the prior art noted
above. The subject device provides an improved hanger
for hanging a radiant tube and reflector heating
assembly from an overhead structure. The new hanger may
be mass produced, resulting in a uniformity of size and
shape unachievable with the old, essentially custom bent
hanger. The new hanger further acts as a dam or
bulkhead to prevent convection currents from moving
along the tube in an "uphill°' direction, i.e., from the
burner assembly to the effluent discharge.
According to the invention~ a rigid member,
capable of withstanding the high temperatures developed
in the emitter tube without deforming, having first and
second ends, an upper surface, a central cutout
y
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communicating with the upper surface, and a bearing
surface located on the upper surface, is used for
hanging and supporting the reflector and radiant tube
assembly from an overhead structure. The hanger is of
such shag"e that it cooperates with a cross section of
the reflector to form an air dam for preventing
convection currents from flowing along the radiant tube.
Another aspect of the invention includes
upwardly extending outboard fingers located on the first
and second ends of the member, adapted to connect the
hanger by a chain or other means to the overhead
structure. In another embodiment, the hanger member is
configured as a flat plate having end and side flanges
used for stiffening and supporting purposes. An
additional aspect of the invention includes at least one
tab adjacent to the central cutout and proximate the
upper surface. The tab or tabs may be bent to allow the
hanger to be placed on the radiant tube and afterwards
bent back to the original position to retain the tube in
~0 the hanger.
In another preferred embodiment, a flat plate
configured to have a shape similar to a transverse cross
section of the reflector has its outer edges bent at
right angles to form stiffening members. By providing
~5 the above described tabs to retain the radiant tube in
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thr central cutout, convection currents along the upper
surface of the tube and reflector/hanger combination are
prevented when the tabs are in the unbent position. The
hanger further has upwardly extending outboard fingers
which are attached by chain to an overhead structures
The hanger of the instant invention may be
stamped out of sheet metal or other material so as to
facilitate mass production of particular sizes in a
quick, efficient and accurate manners Hangers may be
prefabricated for specific reflector configurations to
prevent convection currents from occurring along the
radiant tube.
Brief Description of the Drawing
FIGURE 1 is a side elevational view of a
typical building installation of a radiant tube and
reflector heating assembly;
FIGURE 2 is a front view of the hanger
according to the invention;
FIGURE 3 is a side view of the hanger
of Figure 2; and
FIGURE 4 is an exploded perspective view of a
hanger for supporting a radiant tube and reflector
combination;
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Detailed Description of the Preferred Embodiment
Referring now to Figure 1, a low intensity
radiant energy heating installation 10 is shown to
comprise a gas or oil fired burner 11 located within an
enclosure defined by insulated outer walls 12 of a
commercial building. The burner 11 is connected through
conduit 14 and. adjustable damper 16 to the outside of
the enclosure to provide air for combination with the
gas or oil supplied to the burner 11 through line 18.
Line 18 is provided with valve 20 which may be opened
and closed by means of an external electrical control
signal to emit gas or oil to the burner 11 on demand.
The hot gaseous effluent which is produced by
the burner 11 is admitted to the input end 21 of a
length of emitter tube 22 preferably constructed of
light gage spiral wrapped aluminum, aluminized steel,
steel, or coated steel having low thermal inertia and
high resistance to corrosion, and rib and seam
reinforced for diametrical strength. The length of the
tube 22 may vary greatly with the particular
installation and, by way of example, the nominal
diameter of the tube may be from 2 1/2 to 14 inches.
The metal of the tube is preferably from 22 to 31 gage,
yielding a weight-to-surface area ratio of one or less.
This results in low thermal inertia in the emitter,
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i.e., heat up and cool down times are short. In
contrast, heavy gage welded steel pipes have a
weight-to-surface area ratio of between 3 and 6.
Over substantially the entire working length
of the emitter tube 22 and in spaced and parallel
surrounding relationship thereto is a reflector 24 which
directs radiant energy from the tube 22 toward the floor
13 of the building 12. Hangers 26 are suspended from
the ceiling 15 of the building 12 to hold the
combination of the tube 22, the burner 11 and the
reflector 24 in place.
The tube 22 runs and through a power exhaust
30 and a heat exchanger 28 having an acidic condensate
drain or trap 29. After passing through power exhaust
30 and heat exchanger 28, the now relatively cool
effluent is vented to the atmosphere. The heat
exchanger 28 is optional in the system, but where used
is preferably constructed of materials, such as plastic
or stainless steel, which are highly resistant to
corrosion since the function of the heat exchanger is to
remove heat from the tube 22 toward the exhaust end 23
and direct it back into the building 12. The gaseous
effluent in the tube 22 is preferably cooled to a
temperature below the condensation point. Accordingly,
an acid drain or trap 29 is necessary so that the
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condensate may bE: safely and quickly eliminated from the:
system. In addivion, it is desirable to pitch the cool
portion of the system to ensure a flow of condensate to
the trap/drain 29.
The power exhaust 30 is also preferably
constructed of corrosion resistant materials such as
stainless steel. The use of a power exhaust is
preferable in most cases to a powered supply system in
conduit 14 since the use of power exhaust 30 causes the
entire heating system 10 to operate at a negative
internal pressure, thus eliminating the possibility of
products of combustion flaking into the building 12
~~.hrough cracks .an:d holes in the tube 22.
Further details of 1o-w intensity r-adiant
energy heating system may be found in U.S~ Patent Nosm
3,399,833, 4,716,833 and 4,727,854 all assZgned to the
assignee of the subject invention_m
Figures 2 and 3 illustrate a preferred
embodiment of the hanger 26. The hanger 26 is
constructed of steel, aluminum or other temperature
resistant material capable of withstanding the high ;w
temperatures developed within the emitter tube without
deforming or ~_osing any structural supporting
characteristics. The hanger is generally a trapezoidal
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configuration of sufficient width and height to
substantially surround the emitter tube 22, having an
outer configuration similar to a cross section of the
reflector 24 transverse its longitudinal direction.
The general conf~.guration of the hanger 26 is fabricated
as required to f~.t various shapes of reflectors.
The hanger 26 typically comprises a flat plate
36 having a central cutout 28 for receiving the emitter
tube 22. Perpendicular flanges 28a are provided to
stiffen and reinforce the central cutout 28 and support
the emitter tube 22. The upper surface 29 of the flat
plate 36 contains perpendicular flanges 30 acting as a
bearing surface for the reflector 24. The hanaPr
further includes upwardly extending outboard fingers 32
having holes 32a for attaching a chain 34 or other
support means, such as a cable or solid hangers. The
chain 34 is then attached to an overhead structure or
support 35 located on the ceiling 15 of the building 12.
The flat plate further has edge flanges 38 located
around the periphery of the plate 36 which aid in
stiffening and strengthening the plate 36. Tabs 40 are
provided on the upper surface of the central cutout 28.
Said tabs 40 are bent perpendicular to the plate 36 to
enable the operator to insert the emitter tube 22 into
the central cutout 28. Once the tube 22 has been
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inserted, the tabs 4~ are then bent back in line with
the flat plate 36.
Turning now to Figure 4, it depicts a hanger
26 used in conjunction with an emitter tube 22 and..a
reflector 24 hung by chain 34 to an overhead structure
35. As shown, the hanger 26 substantially encircles the
emitter tube 22 and conforms to the configuration of
reflector 24, thus preventing convection currents due to
temperature chances from flowing along the emitter tube
22 in the direct~Lon shown by the arrow 42.
Since hanger 26 is made from a flat plate bent
and is formed by simple bends, it may be mass produced
in a stamping plant. This mass production results in a
uniform hangers, which in turn allows quick and
efficient installation.
Although a preferred embodiment of the
invention has been illustrated and described in detail,
it will be apparent to one skilled in the art that
various changes may be made in the disclosed embodiment
without departing from the scope or spirit of the
invention, the true scope of which is defined by the
following claims.
