Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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AIR HEATER AND HUMIDIFIER USING DIRECT CONTACT
HEATING PRINCIPLES AND METHOD OF OPERATION
TECHNICAL FIELD
The present invention relates to an air
heater and humidifier using direct contact heating
principles and to the method of operation of the
system.
BACKGROUND ART
Various types of direct contact water
heaters are known and wherein a spray of water is
released on a packing of heat exchange bodies and
through which passes hot gases from a burner chamber
usually located adjacent to the bottom of the water
heater above a hot water reservoir. Accordingly,
the water droplets heat up as they percolate down
the water heater to the reservoir. Such a water
heater is, for example, described in U.S. Patent
5,293,861.
The present invention concerns the use of -
such direct contact water heater principles in a
novel system whereby to provide sources of hot
humidified air originating from fresh air which is
fed in a direct contact air treating chamber where
it is heated and humidified by hot water. It is
mandatory in many countries of the world to admit
fresh air in the heating system of a building for
the comfort of people who work or live therein. It
is known that fresh air penetrates and can be
admitted in a building through cracks or other type
openings and this constitutes a source of fresh air
for its occupants. However, with today's building
construction standards, such openings are
insufficient and therefore fresh air from the
outside must be brought into the heating system.
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Because outside air is very dry in the winter months
and most humidification systems are insufficient, it
is necessary to humidify this air as it is heated.
SUMMARY pF INVENTIpN
It is a feature of the present invention
to provide an air heating and humidifying system
using direct contact--heating principles whereby to
provide sources of hot humidified fresh air which
can be produced from outside dry air.
Another feature of the present invention
is to provide an air heating and humidifying system
using direct contact heating apparatus capable of
also producing hot water supplies for feeding heat
exchangers used in domestic or commercial
applications.
Another feature of the present invention
is to provide an air heating and humidifying system
using direct contact heating apparatus and employing
a single gas burner and wherein the flue gases from
the burner are efficiently cooled to provide a high
efficiency direct contact waterheating system.
Another feature of the present invention
is to provide a method of producing hot humidified
fresh air using the direct contact water heating
principles.
Another feature of the present invention
is to provide a method of producing hot humidified
air using the direct contact water heating principle
while at the same time producing sources of hot
water capable of being used in heat exchangers used
in domestic or commercial applications.
Another feature of the present invention
is to provide a method of producing hot humidified
air - using the direct contact water heating
principles and simultaneously producing a source of
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hot water as well as efficient cooling of the hot
flue gases to produce a very high efficient direct
contact water heating system.
According to the above features, from a
broad aspect, the present invention provides an air
heating and humidifying system using direct contact
heating apparatus. The system comprises a direct
contact water heater having heat exchange means
therein. A water spray means is disposed above the
heat exchange means to supply water thereto and to
cause water to percolate through the heat exchange
means and heat by contact therewith. A hot gas heat
supply is provided below the heat exchange means for
heating the heat exchange means and water
percolating downwards to a reservoir below the heat
supply to produce a supply of hot water. The cooled
flue gases rising through the heater are exhausted
through a flue. Pump means is provided to direct
hot water from the reservoir above a further heat
exchange means in a direct contact air treating
chamber to heat and humidify dry air passing through
a further heat exchange means to provide a supply of
hot fresh moist air at an outlet port of the air
treating chamber_
According to a further broad aspect of the
present invention there is provided a method of
producing hot humidified air using direct contact
heating principles. The method comprises the steps
of providing a source of hot flue gases as a heat
source for.a direct contact water heater whereby to
produce a supply of hot water from a source of
cooler water released over a packing of heat
exchange bodies to extract heat from the hot flue
gases rising through the direct contact water heater
prior to be exhausted through an exhaust flue. Hot
water is fed from the supply of hot water to a
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further direct contact water heater to release same
on a further packing of heat exchange bodies in the
further direct contact water heater. A supply of
cool dry air is fed below the further packing to
extract heat and humidity from water released in the
further direct contact water heater and percolating
through the packing whereby to provide a supply of
hot moist fresh air at an outlet port of the further
direct contact water heater to feed an air
l0 conditioning conduit network of a building.
BRIEF DESCRIPTION OF DRAWINGS
A preferred embodiment of the present
invention will now be described with reference to
the accompanying drawings in which:
FIG. 1 is a schematic diagram of the air
heating and humidifying system of the present
invention using direct contact air heating
principles;
FIG. 2 is a schematic diagram showing a
modification of Figure l; and
FIG. 3 is a fragmented perspective view
showing a typical direct contact water heater column
of the prior art.
DESCRIPTION OF PREFERRED EMBODIMENTS
Referring to the drawings and more
particularly to Figure 3, there is shown, generally
at 10, a typical direct contact water heater of the
prior art and which consists of a casing 11 in which
a packing 12 of heat exchange bodies 13 is supported
elevated therein by a support platform 14 through
which hot gases emanating from the burner flame 15
rise. The casing 11 may have various workable
shapes such as cylindrical, rectangular, etc. A
spray nozzle 16 is supplied with water through an
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inlet conduit 17 and this water is sprayed at 18
over the packing 12 whereby water droplets will be
exposed to rising hot gases and percolate through
the heat exchange bodies 13 which have been heated
by the hot flue gases rising through the packing and
exiting through the outlet flue 19. The hot water
droplets 20 are collected at the bottom of the
casing 11 in a reservoir 21. A pump 22 feeds the
hot water- for domestic or commercial use. The
temperature of the hot flame 15 is controlled by a
control panel 23 which monitors the gas burner 24.
This principle of producing hot water is integrated
in a novel air heating and humidifying system as
will-now be described with reference to Figures 1
and 2.
Referring now to Figure 1, there is
generally shown at 30 the air heating and
humidifying system of the present invention. As
hereinshown, the system utilizes a first direct
contact water heater 31 which is provided with a
packing 32, as in the prior art, constituting a heat
exchange means. A water spray nozzle 33 is disposed
above the packing and sprays water over the hot flue
gases 34 rising through the packing. A gas burner
25- -35 is positioned below the packing 32 and generates
a hot flame 36 which produces these hot gases.
Heated percolating water droplets are collected at
the base of the direct contact water heater 31 in a
reservoir 37.
As hereinshown the hot flue gases 34 at
the outlet port 38 of the first direct contact water
heater 31 are directed to a further direct contact
water heater 40 which is also provided with a
packing 41 but this time the heat exchange bodies
within the packing 41 are heated by the exhaust flue
gases entering the housing 40', as indicated by
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arrow 42, and present at the outlet duct 38 of the
first direct contact water heater 31_ A conduit 43
interconnects the outlet duct 38 to an inlet duct 44
positioned below the packing 41 of the further
direct contact water heater 40. A spray nozzle 45
releases cool water droplets over the packing 41
whereby to cool the hot flue gases 42 as they rise
within the cylindrical casing 40' of the further
direct contact water heater whereby the flue gases
released from the outlet port 46 are cooled
sufficiently to provide exhaust gases at 47 from
which heat has been effectively extracted thereby
resulting in an efficiency which could reach 100$_
The water droplets released from the spray nozzle 45
are heated and dried as they come in contact with
the hot rising flue gases and heat exchange bodies
in the packing 41. These hot water droplets are
collected in a reservoir-48 at the bottom of the
cylindrical casing 40'.
The hot water collected in the reservoir-
48 is fed to a nozzle 51 located in the top end of a
direct contact air treating housing or chamber 50
where it is released over a still further packing 52
of heat exchange bodies which are heated by the
water spray. This hot water is fed to the nozzle 51
through a conduit 53 having a pump 54 connected
thereto.
As hereinshown the direct contact air
treating chamber 50 is provided with a dry air inlet
chamber 55 below the packing 52. A fresh air inlet
conduit 56 is connected to a fan 57 which blows
fresh outside air, as indicated by arrows 58, within
the dry air inlet chamber 55. As the fresh air
rises through the packing and comes in contact with
the hot water droplets emanating from the spray
nozzle 51, it is heated and humidified whereby to be
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released through an outlet duct 59 and within an air -
conditioning conduit network (not shown) of a
building to be air conditioned. As the fresh air
rises through the cylindrical casing 50', it is
heated and the water percolating through the packing
is cooled by heat exchange with the cold fresh air.
This cooled water is collected in a reservoir 60
formed at the base of the cylindrical casing 50'.
This reservoir of cooler water is connected by
conduit 61 and pump 62 to the spray nozzle 45 of the
further or second direct contact water heater 40 to
provide the supply of cold water.
As can be seen in Figure 1, the reservoir
of hot water 48 in the further direct contact water
heater 40 is connected in a closed circuit with its
spray nozzle 45 through the spray nozzle 51 and
reservoir 60 of the direct contact air treating
chamber 50, and this water is continuously
circulated when the fresh outside air needs to be
warmed and humidified. Of course, in the summer
mode of operation, these pumps 54 and 62 are
rendered inoperative and fresh air is admitted to
the conduit network by the fan 57 which blows
outside air directly to the outlet conduit 59 and
into the duct network. A damper 63 is mounted in
the outlet conduit 59 to control the volume of fresh
conditioned air admitted into the duct network.
As is also shown in Figure l, a feedback
conduit 65 is connected between the outlet port 59,
below the damper 63, and the dry air conduit 56
whereby to admit a controlled quantity of hot humid
air from the outlet port 59 back into the dry air
conduit 56 to warm the conduit and the fan 57 to
prevent icing when the supply of fresh air is at a
temperature below freezing. A further damper 66 is
secured within the feedback conduit 65 to control
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the feedback volume. Each of the dampers 63 and 66
are connected to control motors 63' and 66'
respectively and these may be automatically
controlled from a central control panel tnot shown).
Referring again to the first direct
contact water heater 31, it can be seen that one or
more external heat exchangers 70 may be branched in
a closed loop circuit formed by conduit 71 and pump
72 and connected between the hot water reservoir 37
and the spray nozzle 33. Accordingly, the very hot
water present in the reservoir 37 is pumped through
the heat exchanger 30 where heat from the water is
exchanged with cold water fed through the heat
exchanger 70 from conduit 73 which may be connected
to the city supply line 74 through a valve 75. Hot
water at the outlet conduit 76 of the heat exchanger
70 can then be fed to feed a a hot water tank for
domestic use or may be fed -to other commercial
devices such as laundry apparatus or other
processes. As pointed out one or more of these heat
exchangers 70 may be connected in seriesor in
parallel arrangment. The heat exchangers 70 may
also be a series of radiators to heat air.
Referring now to Figure 2, there is shown
ZS a further modification of the system 30_ As
illustrated, the hot exhaust flue gases 42 fed to
the inlet conduit 44 of the cylindrical casing 40'
herein originate from an external boiler 80 which
serves in another application, such as a laundry.
The hot flue gases 42 at the outlet flue 81 of the
boiler can be directed through an interconnecting
flue pipe 82 to the inlet port 44 of the further
direct contact water heater 40 by closing a damper
valve 83 in the outlet flue 81 above the conduit
connection 82. Accordingly, in this application the
system becomes very efficient as the exhaust flue
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gases from the boiler are recovered and provide the
heating source for the further direct contact water
heater 40. These flue gases are sufficiently cooled
to produce a system of very high efficiency in the
range of 100~
Briefly summarizing the method of
operation, there is provided a heat source which
generates hot flue gases 42 while producing a supply
of hot water 48 from a source of cooler water
released through the spray nozzle 45 and released
over the packing 41 of heat exchange bodies whereby
to extract heat from the hot flue gases 42 rising
through the direct contact water heater cylindrical
casing 40'. These hot flue gases are released
through the exhaust flue 46 and these have been
sufficiently cooled to achieve high efficiency. The
hot water from the supply of hot water 48 is fed to
a further spray nozzle 51 to be released over a
further packing 52 of heat exchange bodies in a
further direct contact air treating chamber or
casing 50, 50'as shown in Fig. 1. A supply of
fresh air 58 is fed below the packing 52 to extract
heat and humidity from hot water which is released
in a spray into cylindrical casing 50' and which
percolates through the packing 52 to provide a
supply of hot moist fresh air at 58' at the outlet
port 59 of the air trating chamber 50 whereby to
feed an air conditioning duct network of a building.
The method also encompasses all of the other aspects
of the operation of the system above-described.
It is within the ambit of -the present
invention to cover any obvious modifications of the
examples of the preferred embodiment described
herein, provided such modifications fall within the
scope of the appended claims.
