An air curtain generator is provided in which an arrangement is
incorporated for purposes of heating input air so that an air curtain
is generated which is formed with heated air. The air is heated
by igniting a mixture of combustible gas and air with the combustion
products thereof being distributed through an elongated conduit
provided with openings through which the combustion products are
discharged. Intake air flows over the conduit into an air curtain
generator which causes the thusly heated air to be distributed along
a rectilinear path to form an air curtain.
What is claimed is:
1. Apparatus comprising air curtain generating means for directing
a flow of air along a path to constitute an air curtain, said air
curtain generating means having an opening for the intake of air,
and heating means to heat air for supply to said intake opening
and thence to said path; said heating means including a conduit
provided with an axial bore and radial openings positioned along
said conduit, a supply of combustible gas, and burner means coupled
to said supply of combustible gas to burn the gas in mixture with
air to provide heated combustion products, said burner means being
coupled endwise to said conduit so that said combustion products
are supplied axially through said axial bore and via said radial
openings to the intake opening.
2. Apparatus as claimed in claim 1 wherein said heating means includes
a casing enclosing said conduit and having an opening for the admission
3. Apparatus as claimed in claim 2 comprising shield means within
said casing for protecting the casing from heat radiated by said
4. Apparatus as claimed in claim 3 wherein said shield means includes
two generally horizontal arcuate shields bracketing said conduit
and providing inflow and outflow paths to guide air around the conduit
to mix with the combustion and to pass to said intake opening.
5. Apparatus as claimed in claim 1 wherein said air curtain generating
means has an effective length along which said conduit extends at
least substantially fully, said radial openings being distributed
along the length of said conduit.
6. Apparatus as claimed in claim 1 wherein said conduit is parallel
to said path and said burner means includes a nozzle extending into
said conduit to generate combustion products which are distributed
via said radial openings.
7. Apparatus as claimed in claim 2 wherein said air curtain generating
means includes a casing generally equal in size to the first said
8. Apparatus as claimed in claim 7 wherein said casings are horizontally
arranged in parallel and in juxtaposition, the casing of said air
curtain generating means including means for directing the air curtain
9. A method comprising heating air and causing the thusly heated
air to flow along a rectilinear path as an air curtain, said method
comprising heating the air by burning a combustible gas to form
heated combustion products which are discharged into the air and
directing the combustion products through radial openings distributed
along a conduit, the air which is to be heated being caused to flow
around the conduit to mix with the combustion products.
10. A method ad claimed in claim 9 burning the gas by mixing the
gas with air and igniting the same.
11. A method as claimed in claim 9 wherein the air which is to
be heated is passed around the conduit in a direction at right angles
to the general flow of combustion products through the conduit.
12. A method as claimed in claim 11 wherein the air curtain is
directed vertically downwards.
13. A method as claimed in claim 11 comprising intercepting radiation
from the conduit to limit radial transmission thereof.
14. A method as claimed in claim 11 comprising aligning the conduit
in parallel with the air curtain.
FIELD OF INVENTION
This invention relates to air blowing apparatus and methods and
more particularly to apparatus and methods for producing air screens,
barriers and/or curtains. The invention relates more particularly
to methods and apparatus for heating air upon the introduction thereto
into an air blowing apparatus for purposes of generating air curtains
which are thus formed with heated air or the like.
In my earlier U.S. Pat. No. 4,450,755 which issued May 29, 1984
I disclosed a blower apparatus provided for the generation of an
air curtain, screen or barrier. The apparatus of the aforemention
patent includes a blower in the form of a plurality of blades arranged
to describe a cylinder and a guide is provided which encircles the
blower but which is open-ended and extends axially beyond the blower
to generate an airstream, the width of which is greater than that
of the blower. In addition in the apparatus of the aforementioned
patent a deflector or interceptor plate is arranged which is coextensive
with that portion of the guide which extends beyond the blower and
which is coextensive with a portion of the blower in a moderate
range thereof. The deflector or interceptor plate prevents air from
circulating in an axial direction back into the blower and therefore
improves the effectiveness of generation of the airstream which
flows tangential out of the blower arrangement.
In the aforesaid patent the casing which houses the fan is provided
with an intake opening covered with a screen and capable of admitting
intake air This intake air flows into the casing at an angle which
is perpendicular to the discharge of such air in the form of an
air curtain or the like. In the apparatus of U.S. Pat. No. 4,450,755
the temperature of the air relies upon ambient conditions in the
space in which the air blowing apparatus is installed. This means,
since there is no provision for controlling the temperature of the
air which is employed and discharged, that the temperature of the
air curtain depends upon the temperature of the air which is fed
into the system without any control being exercised thereupon. Accordingly
it is frequently possible and even usual that the air of the air
curtain which is generated is cold air which may be uncomfortable
and humid and which is hardly likely to be ergonometrically qualified
to offer the most suitable conditions for employees and the like
who in the performance of whatever functions are assigned to them
may have to pass through the opening which is being protected by
the air curtain which is being generated.
SUMMARY OF INVENTION
It is an object of the invention to provide improved air blower
arrangements and methods for producing air screens and the like.
It is another object of the invention to provide improved apparatus
and methods for the generation of air curtains and the like with
temperature control thereof
It is yet another object of the invention to supplement the operation
of an air blower apparatus and related methods by the provision
of a heat generator which functions to add heat to intake air.
In achieving the above and other of the objectives of the invention
there is provided generally and as will be described in greater
detail hereinbelow an apparatus which comprises an air curtain generating
arrangement for directing a flow of air along a path to constitute
an air curtain or the like, the air curtain generating arrangement
having an intake opening for the intake of air, and a heating arrangement
to heat air for supply to the intake opening and thence to the aforementioned
path. The heating arrangement of the invention will preferably include
structure to burn a mixture of gas and air to add the combustion
products thereof to the air being supplied to the intake opening.
More specifically, the heating arrangement may include an elongated
conduit provided with an axial bore and radial openings, a supply
of combustible gas coupled to this axial bore, and apparatus to
burn the gas in mixture with air to provide heated combustion products
which are supplied to the intake opening.
According to a specific embodiment of the invention the heating
arrangement includes a casing enclosing the conduit and having an
opening for the admission of air. As a feature of this embodiment
a shield arrangement is provided within the casing for protecting
the casing from heat which is radiated by the conduit.
According to other features of the invention as will be described
in greater detail hereinbelow, the shield arrangement may include
preferably two arcuate shields bracketing the conduit and forming
inflow and outflow paths to supply air to and around the conduit
and to enable the air to continue on into the aforementioned intake
opening of the air curtain generator arrangement.
According to another feature of the invention the air curtain generating
arrangement has an effective length along which the conduit extends
at least substantially fully and in parallel. It will be noted in
the preferred embodiment which is described hereinafter that the
casing of the heating arrangement is generally equal in size and
shape to the casing of the air curtain generator arrangement. It
will also be noted that these casings are horizontally arranged
in parallel and in juxtaposition with the casing of the air curtain
generating arrangement directing the air curtain vertically downwards.
In accordance with the method of the invention there are comprised
the steps of heating air and causing the thusly heated air to flow
along a rectilinear path as an air curtain The air is preferably
heated according to the invention by burning combustible gas to
form heated combustion products which are discharged into the air
which is ultimately caused to flow along the aforementioned rectilinear
path. The gas is preferably burned by mixing a combustible gas with
air and igniting the thusly resulting mixture
According to other aspects of the invention and as has been generally
indicated hereinabove, the combustion products are directed through
a conduit provided with openings with the air which is to be heated
being caused to flow around the conduit. It will also be noted that
the air which is to be heated is passed around the conduit in a
direction at right angles to the general flow of combustion products
through the conduit and that the air curtain is directed vertically
Other features of the invention include intercepting radiation
from the conduit to limit radial transmission thereof and aligning
the conduit in parallel with the air curtain.
Other objects, features and advantages of the invention will be
found in the following detailed description of a preferred embodiment
thereof as illustrated in the accompanying drawing.
BRIEF DESCRIPTION OF DRAWING
In the drawing:
FIG. 1 is a partially diagrammatic perspective view of a preferred
embodiment of the invention;
FIG. 2 is a diagrammatic sectional view taken along line II--II
of FIG. 1;
FIG. 3 is a diagrammatic top view of the structure of FIGS. 1 and
FIG. 4 is a diagrammatic end view of the apparatus of the invention
as illustrated in FIG. 3 ; and
FIG. 5 is a perspective partially diagrammatic view of a burner
constituting a heating arrangement component in accordance with
In U.S. Pat. No. 4,450,755 is shown a casing having an inlet opening
and a discharge opening arranged such that air is discharged along
a rectilinear path at right angles to the entry direction of intake
air into a casing which is provided to shield the functional elements
of the air blower arrangement disclosed in this patent. Further
shown are a plurality of fan arrangements connected together for
simultaneous rotation whereby intake air is caused to be whirled
centrifically. This air is cast off and is directed by a scroll
arrangement to follow a path which leads to discharge as an air
curtain. Deflector plates are provided which extend beyond the axial
extents of the fans to increase the effective widths of the air
curtain. These deflectors prevent the air from moving out of the
air curtain path to be redirected for undesired recirculation into
the various fans.
As has been mentioned hereinabove, the temperature of the air as
well as the humidity conditions thereof depend upon the nature of
the intake air being supplied to the air curtain generator. This
may frequently be undesirable since the blowing of cold moist air
in the form of an air curtain may seriously affect the environmental
conditions as well as health conditions in which factory personnel
and the like may have to work especially when their duties cause
them to pass through the air curtains being generated.
The air blower arrangements or air curtain generator of U.S. Pat.
No. 4,450,755 is shown diagrammatically at 10 in the attached drawing.
In some of the Figures, notably FIGS. 1 and 2, a fan arrangement
12 is shown therein encircled by a scroll arrangement 14 which causes
the circulated air to pass through an opening 16 and to follow a
rectilinear path downwardly and vertically as indicated by the arrows
at 18. In the prior embodiment this intake air passes through an
opening indicated at 20 which may be in the form of a screen or
the like which screens out undesirable impurities such as leaves,
scraps of paper, insects and the like. The path which the intake
air follows through the opening 20 is perpendicular to the direction
indicated by arrows 18 and is therefore generally horizontal.
In accordance with the invention there is provided a further casing
22. This casing 22 is generally square or rectangular in cross section
as is the casing 24 of the air blower arrangement 10. These two
casings 22 and 24 are generally and preferably of the same order
of magnitude of.-size and/or cross section.
In further accordance with the preferred embodiment of the invention
the casings 22 and 24 are elongated thereby to provide an elongated
air curtain the length of which exceeds the length of the fan arrangement
12 by reason of the provision of the deflector plates which operate
as set forth in detail in U.S. Pat. No. 4,450,755.
According to a feature of the invention there is provided extending
longitudinally through the casing 22 an elongated conduit 26 fabricated
for example of a lightweight metal such as thin steel or possibly
aluminum and preferably fabricated of a plastic such as polyethylene,
polystyrene or the like capable of withstanding elevated temperatures
the nature of which will become hereinafter apparent. This conduit
will have a wall strength capable of making the weight of the conduit
self-sustaining and will have a diameter D which is capable of permitting
the development of a pneumatic head which is capable further of
permitting a radial discharge of combustion products as will be
explained more fully hereinbelow.
An important component of the invention is indicated at 30. Component
30 is a heating arrangement which takes in a supply of ambient air
and mixes the same with a combustible gas fed via pipe 32 under
the control of an electrical control 34. The combustion mixture
is forced out and into the internal bore 36 of the conduit 26 via
a tube 38 which is inserted internally of the bore 26. The function
of heating arrangement or burner 30 is to take a mixture of combustible
gas and air, mix the same and controllably ignite the same while
supporting the combustion thereof in a nozzle thereby to cause the
generation of a flame and the issuance of heated combustion products.
By reference to FIG. 5 one will note a perspective view of a commercially
available burner which may be utilized in accordance with the precepts
of the invention. One such burner is Model OE-B produced by the
American Burner Corp. of Commack, N.Y. This model is capable of
providing by way of example a heat output of 200,000-400,000 BTU/hr
of natural gas origin. It is provided with a crown head indicated
at 50 for the generation and retention of a flame for compact combustion.
It is furthermore provided with a spark ignition under the control
of a unit 52 and a solenoid control 54 for the supply of natural
gas or other such combustible gas via a pipe 56. The unit is provided
with a one-quarter horsepower motor although larger or smaller sizes
may equally well be provided. It is also provided with a pre-purge
air system and a flame rod control (not shown) to facilitate the
functioning of the apparatus.
The flame which is generated and the combustion products which
result pass axially through the conduit 26 as shown generally by
the arrow 60. The remote end of the conduit 26 is preferably obturated.
The conduit is however provided with a multitude of radial openings
62 and 64. These openings may be aligned in parallel rows or alternatively
may be arranged in spiral or other such patterns around the conduit.
Their sizes may be varied along the length of the conduit 26 thereby
to accommodate decreasing pneumatic head from one end of the conduit
to the other. The bore of the conduit may range for example from
3 to 24 inches. The openings 62 and 64 may for example range between
1/8 and 21/2 inches. These size ranges may be exceeded in either
direction without surpassing the scope of the invention. What is
essential is that sufficiently heated combustion products and accompanying
unburned air will be mixed with intake air to supply an air curtain
of desired temperature having the humidity thereof generally abated
The flow of heated combustion products through the conduit 26 may
cause a radial radiation of heat which might undesirably heat the
outer casing 22. To avoid this undesired radiation as well as perform
another function to be mentioned hereinbelow there may be provided
a plurality of shields. Two arcuate shields 70 and 72 are illustrated.
They are spaced from the conduit 26 by a distance which may generally
be in the order of magnitude of 1/4 to 1/2 the diameter of the conduit
and serve to define an inflow path 74 and an outflow path 76. They
also form paths 78 and 80 by means of which intake air indicated
by arrows 82 are caused to flow through inflow opening 74 and via
paths 78 and 80 around the conduit 26 and thence via outflow opening
76 into the intake opening 20 of the air curtain generator arrangement
10. Thus, the shields 70 and 72 perform the function of shielding
the casing 22 from undesired radiation from the conduit 26 and of
confining the flow of some of the air around the conduit 26 to provide
for ready mixing thereof with heated combustion products flowing
outwardly through openings 62. The shields, also provide a further
function, this function being that of guiding the flow of air towards
the intake opening 20 of generator 10 although this function is
aided by the negative pressure created by the fan arrangement 12
of the generator 10.
The opening of casing 22 is generally indicated at 90. This opening
is preferably screened also to prevent the entry of undesirable
contaminating objects and especially those which may be inflammable.
Although not shown, the intake openings may be provided with dampers
or other controls which serve to control the magnitude of air flowing
into the system thereby to aid in temperature control and pressure.
It will be noted also that casings 22 and 24 are mounted in parallel
and juxtaposition with each other being furthermore parallel to
the air curtain indicated at 18. Similarly, the conduit 26 has an
axis of symmetry which is parallel to but spaced from the air curtain
18 so that consequently the conduit 26 is likewise parallel to the
It will therefore be observed that the method of the invention
comprises heating air and causing the thusly heated air to flow
along a rectilinear path as an air curtain while heating the air
by burning a combustible gas to form heated combustion products
which are discharged into the intake air before it is formed as
an air curtain. It will be noted further that the heating is preferably
effected by burning the combustible gas (e.g. natural gas, etc.)
upon mixing the same with air and igniting the thusly resulting
mixture The combustion products which are heated are then directed
through a conduit provided with openings through which the heated
combustion products escape in a radial direction. Air to be heated
is caused to flow around the conduit to mix with and be heated by
the escaping combustion products. The air is passed around the conduit
in a direction at right angles to the general flow of combustion
products through the conduit before they escape radially therefrom.
A feature of the method of the invention involves intercepting
radiation from the conduit to limit the radial transmission thereof.
The foregoing objects and advantages of the invention are not necessarily
limiting of the same since variations may be effected to achieve
slightly different objects other than those envisaged above.
There will now be obvious to those skilled in the art many modifications
and variations of the structures and methods set forth hereinabove.
These modifications and variations will not depart from the scope
of the invention if defined by the following claims.