Note: Descriptions are shown in the official language in which they were submitted.
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AIR MODULAT~D IN DUCT ~UM]:DIFICATION
AND EVAPORATIVE COOLING SYSTrM_
Cross-Reference to Related Application -
_ . _ _ . . .
This application relates to Applicant's copending
Canadian Patent Application Serial No. 498,392, filed December
20, 1985, for IN DUCT ATOMI~ING HUMIDIFICATION AND EVAPORATIVE
COOLING SYSTEM.
Background of the Invention -
The referenced prior patent application discloses a
humidification and evaporatlve cooling system in which a modulat-
ing valve placed in the water supply line of the system is
opened and closed in response to an air signal to restrict or
increase the flow of water to in duct spray heads in order to
satisfy humidification and evaporative cooling requirements.
The present invention improves on the system in the prior
application by providing a new and better method of modulating
the water discharge from the spray heads, whereby each spray head
can be individually modulated. In the new technique, the
modulation is accomplished by pressurizing the rear chamber of
each air and water spray head with control air. The modulating
water valve disclosed in the prior application is eliminated from
the control section of the improved system in accordance with the
present invention.
In accordance with the present invention, in response to a
demand for humidity, the control section of the system operates
to open ~he air and water solenoid vaiveæ in the air and water
A ~7~
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supply lines so tha~ air and water can flow to the in duct spray
heads. ~ separate pneumatic control system delivers a
pneumatic pressure signal to a fitting connected in the rear
chamber oE each system spray head. As the pneumatic pressure
signal to the rear of each spray head, behind its diaphragm, is
increased or decreased, such signal will off-set or counteract a
part of the water pressure acting on the forward side of the
diaphragm. As the differential between the control air pressure
and water pressure on the opposite sides of the spray head
diaphragm is increased or decreased, it will cause the spray
head plunger mechanism controlling the outlet of water to shiEt
rearwardly or forwardly, thereby increasing or decreasing the
flow of water through that particular spray head.
Therefore, once air and water flow to a spray head of the
system is established, a decreasing pneumatic pressure signal
will allow the plunger in each spray heacl to retract or open
further, thereby permitting an increased flow of water through
the spray head. As the system modulates downwardly, the control
air pressure in the rear oE the spray heads is increased, causing
the plunger to move forwardly, in turn causing the water flow in
the head to be restricted and the output of water from the head
to be correspondingly diminished.
Among the advantages derived from this new method of air
modulation of the system are the following:
lj The previous method of modulating the system with a
water modulating valve had an operational range of only 2-3 psi
water pressure, whereas the improved method of modulation has an
operational range of 10 psi control air pressure.
2) The proportional air/water output from the spray heads
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can be IllUCIl more precisely controlled, wi~h no hysteresis, and
absolutely positively shut oEE.
3) The previous method of modulation was limited to a
system having a minimum capacity of 120 lbs./llr. of w~ter, while the
improved method is unlimited in the sense that a single spray
head can be mod~lated, or a manifold containing 100 or more
spray heads could be modulated.
~ l) By a~justment of the tension oE the plunger spring in
the rear chamber of each spray head, the modulation range can ~e
adjusted. For example, in a manifold having two heads, one head
can be adjusted to operate from zero to full capacity over a
range of 0-10 psi pneumatic signal input. The second spray head
on the manifold could be adjusted to operate from zero to full
capacity over the range of 10-20 psi pneumatic signal input.
This enables the installation of a manifold which can have
several stages of operation from a single 0-20 psi pneumatic
signal input. In the prior method, multiple manifolds were
required to achieve multiple stages of operation in the system.
5) The improved method of modulation additionally allows
the mounting of spray heads at different elevations while being
supplied from the same control section of the system. Previously,
all heads of a single system required mounting at exactly the
same level, to avoid differences in water column pressure.
The system according to the prior referenced application
is most suitable where large capacitie$ of 200 lbs.Ihr. or more
are involved. In such systems, the use of a water modulating
valve may be prefera~le. Ilowever, generally speaking, systems
having capacities under 200 lbs./hr. should be modulated
pneumatically, and without the use oE a water modulating valve,
in accordance wi~h tlle present invention.
1.~7~ 13
In one embodiment of the presen-t invention,
there is l)rovided an air modulated in duct humidification
and evaporative cooling system comprising at least an
air/water spray head having a pneumatic control chamber
adapted for mounting within an air supply duct, the
air/water spray head having an air receiving passage and
outlet means and a water receiving passage and ou-tlet
means, and a diaphragm element separa-ting -the water
receiving passage and outlet means from the pneumatic
control chamber, a valve stem in the water receiving
passage and connected to one side of -the diaphragm to
operatively control -the water outlet means, spring means
in the pneumatic control chamber connected to the
opposite side of the diaphragm from the valve stem to
bias the valve stem to close the water outlet means, in
duct relative humidity sensor/transmitter means, external
pneumatic modulating signal generating means operatively
connected with the in duct relative humidity
sensor/transmitter means, control air delivery means
connected with the pneumatic modulating signal genera-ting
means, pressurized water and pressurized air supply means
connected with the water receiving passage and outlet
means and the air receiving passage and outlet means of
the air/water spray head, and a pneumatic signal delivery
line connected between the pneumatic modulating signal
generating means and the pneumatic control chamber of the
air/water spray head, whereby the pressure of a varying
pneumatic modula-ting signal in the pneuma-tic con-trol
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chamber and the biasing force of -the spring means is
balanced against -the pressure of water on the one side of
the diaphragm -to modulate the output of water hy the
air/water spray head to maintain a required degree of
relative humidity and evaporatlve cooling within an air
supply duc-t.
In a still further embodiment, there is
provided an air modulated in duct humidificat.ion and
evaporative cooling system comprising a plurali-ty of
air/water spray heads adapted for m~unting within and
across the air flow axis of an air supply duct, each
air/water spray head having a pneumatic control chamber,
in duct relative humidity sensor/transmitter means,
external pneumatic modulating signal generating means
operativel.y connected with the in duct relative humidity
sensor/transmitter means, control air delivery means
connected wi-th the pneumatic modulating signal generating
means, pressurized water and pressurized air supply means
connected with the plurality of air/water spray heads,
means connected between the pneumatic modulating signal
generating means and the pneumatic control chambers
comprising a pneumatic signal delivery line leading to
the control chamber of one air/water spray head and
jumper pneumatic signal delivery lines connected serially
between -the one air/water spray head and the control
chamber of the other air/water spray heads in the
plurality, whereby a varying pneumatic modulating signal
A
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in the pneumatic control chambers can modulate the ou-tput
of water by the plurali-ty of air/wa-ter spray heads -to
maintain a required degree of relative humidity and
evaporative cooling within an air supply duct.
In yet another embodiment, there is provided an
air modulated in duct humidifica-tion and evaporative
cooling system comprising a plurality of air/water ~pray
heads each having a water receiving passage and outlet
means, an air receiving passage and outlet means and a
pneumatic control chamber isolated from the water
receiving passage and outlet means by a diaphragm
element, pressurized water and pressurized air delivery
manifold means connected with the water and air receiving
passage and outlet means of the spray heads, external
pneumatic signal generating means delivering a modulat'ng
pneumatic signal to the pneumatic control chamber in each
air/water spray head to modulate the output of water from
each spray head to satisfy varying relative humidity and
evaporative cooling demands in a building air supply
duct, and in duct separated return air and supply air
relative humidity sensor/transmitter means, each
operatively connected with the pneumatic signal
generating means.
Other features and advantages of the invention
will become apparent to those skilled in the art during
~he course of the following detailed description.
Generally speaking, the present invention has -the same
objectives and abilities set forth in the prior
application for an in duct atomizing humidi~ication and
e~aporative cooling system.
S ~ ol r~ WINGS
Figure 1 is a fragmentary perspective view,
partly broken away, of an in duct air modulated
humidifica-tion and evaporative cooling system according
to one embodimen-t of the present inven-tion;
Figure 2 is an enlarged central vertical
section taken through one spray head of the system shown
in Figure l; and
Figure 3 is a pneumatic-electrical system
schematic view of the embodiment of the invention shown
in Figure 1.
DETAILED DESCRIPTION OF T~E PREFERRED EMBODIMENTS
Referring to the drawings in detail wherein
like numerals designate like parts throughout the
same, Figure 1 depicts the physical arrangement of
the system according to one embodiment of the
invention with relation to a main air supply duct
10 of a commercial or industrial building. A
system pressurized air supply line 11 external to
the duct 10 and extending along one side wall thereof
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supplies system air typically at 45 psi. Similarly, a system
water supply line 12 externally of the duct 10 supplies system
water typically at 45 psi. The air and water supply lines 11 and
12 deliver air and water, respect~vely, to an air manifold 13 and
a parallel water manifold lll, disposecl within the main air duct
10 and extending transversely across its air flow axis, preferably
at right angles thereto.
The air manifold 13 mounts a required number of atomizing
air/water spray heads 15, one of which is shown in detail in
Figure 2. The spray outlets of the heads 15 can be directed
alternately in opposite directions as shown in Figure 1, although
in some cases the spray head outLets can be directed in the same
direction, such as upwardly or downwardly. In any case, a
sufficient number of the spray heads 15 is provided on the
manifold 13 to span the width of the duct 10, so that humidifying
and cooling sprays can be delivered across substantially its full
width.
Referring to Figure 2, each spray head 15 includes a body
16 having a forward chamber 17 spanned by an elastic diaphragm 18
secured by a rear clamping head 19 having a threaded closure plug
20. A rear control air chamber 17a is provided in the clamping
head 19 on the rear side of diaphragm 18. A cont~ol air inlet
fitting l9a is provided on the clamping head 19 and the purpose
of this fitting will be fully described. A water nozzle 21 has
threaded engagement with an extension 22 of the body 16, and has
a bore 23 receiving a stem 24 of a central plunger 25, urged
forwardly by a spring 26 behind the diaphragm 18. The tension of
t[le spring 26 can be adjusted over a range to adjust the modulat-
ing range of the system, as will be further explained. A threadec
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spring tension adjusting screw 26a is provi~ed, as shown. The
plunger 25 carri.es a seal 27 which engages an opposing seat 28 of
the water nozzle 21.
The stem 24 at its forward end carries a cleaning needle
29 wllich.normally projects into a small water outl.et oriEice 30
of the nozzle 21. An air nozzle tip 31 having an outlet orifice
32 for air'and water surrounds the nozzle 21 with the two
orifices 30 and 32 coaxially aligned. The air nozzle tip 31 is
threadedly engaged with the body 16, as shown.
Each spray head 15 has a system air inlet port 33 opening
through one side thereof and being threadedly connected to an air
supply ~ranch 31~ of the air manifold 13. The air inlet port 33
communicates with the outlet orifice 32 by flowing through the
annular space between the water nozzle 21 and ai.r nozzle tip 31.
On its opposite side, each spray head 15 has a water inlet port
35 threadedly coupled to a water supply tube 36 having its
opposite end coupled to the water manifold 14.
When pressurized system water is delivered by one of the
tubes 36 to the inlet port 35 of a spray head 15, the pressurized
water acts on diaphragm 18 and unseats the seal 27, allowing wate
to enter the bore 23 and to discharge through the orifice 30.
Simultaneously, pressurized system air from one of the branches
34 enters the port 33 and passes to and through the orifice 32
along with ent-rained water exiting through the orifice 30. This
results in a very fine atomization of water droplets entrained
in air exiting through the orifice 32 of each spray head 15. The
water droplets have an average size of approximately 7.5 mi.crons.
Such droplets rapidly evaporate to the gaseous state in the air
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duct 10 to raise tlle level of relative humidity therein, and
provide evaporative cooling. The spray head l5 per se is
preferably of the type disclosed in U.S. Patent 2,825,602.
lhe system includes within the duct 10 a return air
humidity sensor/~ransmitter 37, manufactured by Barber Coleman
Co., Loves Parlc, Illinois, No. IIKS-2033, and a supply air
humidity sensor/~ransmi~ter 37a identical to the type identified
above. The return air humidity sensor/transmitter 37 is placed
in the duct lO upstream from the two manifolds 13 and 14, and the
supply air humidity sensor/transmitter 37a is placed in the duct
10 downstream from the manifolds 13 and 14, and immediately ahead
of the first bend or obstruction 38 in the duct 10 (see Figure 3).
A controls cabinet 39 mounted outside of the duct 10
contains two gages 40 and 41 which display, respectively, the
return air (control) relative humidity and the supply air (hi~h
limit) relative humidity. These gages are identical and are
manufactured by Barber Coleman Co. as No. AKS-9081.
Also within the cabinet 39 are a control receiver/
- controller 42 and a high limit receiver/controller 42a which are
identical devices manufactured by Barber Coleman Co., No.RKS-1001.
Within the cabinet 39 is a low signal selector (comparator)
43, manufac~ured by Barber Coleman Co., No. AK-51642. The
elements 42, 42a and 43 are interconnected by pneumatic signal
lines 44 and 45. The elements 37 and 42 and 37a and 42a are
connected by pneumatic signal lines 46 and 47.
System control air, preferably at 20 psi, enters the
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system througll a control air supply line 48, havlng connections
with the elements 42, 1l2a and 43, as indicated at 49, SO and 51
in Figure 3. Arlother pneumatic signal line 52 for the signal
selected by the low signal selector (comparator) 43 leads from
the element l~3 to a reversing relay 43a within the cabinet 39,
with which the line 52 is operatively connected.
Within the ca~inet 39, the pneumatic signal line 52 is
connected in parallel relationship to the reversing relay 43a
an~ to a lateral pneumatic line 54, in turn connected to a
pneumatic pressu~e-operated electric switch 55 having a contactor
56. A system on-ofE electrical switch 57 on the face oE cabinet
39 has one terminal thereoE connected with a 115 volt AC power
supply 58 (Fi~ure 3).
A companion pneumatic pressure-operated electric switch 59
having a contactor 60 is connected by a conductor 61 to the
solenoid of a three-way water solenoid valve 62, connected in the
water supply line 12. The three-way valve 62 is manufactured by
Automatic Switch Co. (ASCO~, Florham Park, N. J. as No. 8316c2l~.
The switch 59 is manufactured by Automatic Switch Co. as No.
PAlOA/RElOAll. The switch 59 is connected in the air supply line
11 for operation by the pressure therei.n.
The terminals 63 and 6l~ of switch contactors 60 and 56 are
interconnected by a conductor 65, having a branch conductor 66
leading to and connected with a two-way air solenoid valve 67,
manufactured by Automatic Switch Co. as No. 8210D2. The two-way
solenoid valve 67 is connected in the system air supply line 11.
Also connecte~ in the water supply line 12 is a water pressure
regulator 68 manuEactured by Watts Regulator Co., Lawrence, Mass.
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as No. U5LP10-35. An air pressure regulator 69 is connected in
the air supply line 1]. clowns~ream from the air solenoid valve 67.
The regulator 69 is manu~actured by Penn ~i.r Co., York, Pa. as
Valve Model No. 11-002-069. ~ll of the above-enumerated control
components are standard commercial items. The pneumatic signal
reversing relay 43a is manufactured by Barber-Coleman Company,
Loves Park, Illinois, Model No. Al~50163.
ReEerring to ~igure 1, the air supply line 11 is prefer-
ably equipped with an upstream conventional manual shut-off valve
70, a pressure gage 71 and a ~ilter 72 in the order and arrange-
ment shown. None of these conventional elements plays a part in
the functioning of the system controls shown in Figure 3.
Similarly, the water supply line 12 contains a shut-off valve 74,
a pressure gage 75 and another s~andard gage 76 which is used in
coniunction with the air compressor gage in setting up the system
to assure proper pressure at the spray heads 15. A third ~age 77
on che face of cabinet 39 displays the pneumatic pressure signal
going to tlle reversing relay 43a.
As noted previously, the modulating water valve disclosed
in the referenced prior application is eliminated in the present
invention and tlle modulating function is talcen over by the
pneumatic control means directly. More particularly, the
reversing relay 43a common to the several spray heads 15 is
connected by an air line 43b to the air inlet fitting l9a of one
endmost spray head 15 on the manifold 13, the fitting 19a being
in communication with the rear control air chamber of ~he spray
head, as previously described. The rear control air chambers 17a
of the other spray heads 15 on the manifold 13 are serially
connecte~ througll tlleir air inlet flttings 19a by jumper air
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lines 43c, ll3d, and 43e, etc.
OPERATION
With air flowing through the main duct 10 leading to
various branch dllcts of a building and with the des~ribed
automatic air modulated humidification and evaporative cooling
system components and their controls installed, and with system
air and water at the proper pressures being delivered to the
lines 11 and 12, and control air at the proper pressure being in
the line 48, the system operates in the ~ollowing manner.
The main on-o~f switch 57 is closed to supply 115 volts ~C
to the system, necessary to allow the pneumatic pressure-operated
electric switches 55 and 59 to operate in connection with the
solenoids of the three-way and two-way valves 62 and 67 in the
water and air supply lines 12 and 11.
The return air humidity sensor/transmitter 37 sends a
pressure signal via the pneumatic line 46 proportional to the
relative h'umidity of the air which it is desired to control.
This signal is displayed on the relative hulllidity gage 40. The
same pneumatic signal is received by the return air receiver/
controller 42 which in turn outputs a pneumatic slgnal through
the line 44 which is proportional to the amount which the set
point humidity setting selected on the receiver/controller 42
exceeds the actual humidity level being sensed by the sensor/
transmitter 37. It will be understood that the return air
receiver/controller 42 and supply air receiver/controller 42a
are preset to enable the system to establish and maintain the
desired humidity control with evaporative cooling.
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I,ilccwise, tlle supp]y air l~umidity sensor/transmitter 37a
sends a pneumatic pressure signal through the line ~7
proportional to the relative humidity of the air which the
system is required to Iceep within allo~,7able limits. This signal
s is displayed as relative humidity on the gage 41. The same
signal is received by the supply air humidity receiver/
controller 42a~ which in turn outputs a pneumatic signal through
~he line ~l5 which i~ proportional to the amount which the set
point selected Oll the receiver/controller 42a exceeds the actual
humidity level being sensed at the supply air humidity sensor/
transmitter 37a.
The ~wo pneumatic si~nals from the return air and supply
air receiver/controllers 42 an~ ll2a are delivered to the low
signal selector (comparator) 43. This device compares the two
signals and outputs the lower of the two signals through the line
52 connected to the pressure controlled switch 55 and the
reversing relay 43a. The pneumatic signal through the line 52
and lateral line 54 causes closing of the normally open contactor
56 of switch 55. The closing of the contactor, through the
completed electrical circuit, opens the two-way air solenoid
valve 67, which then supplies air at a ?ressure governed by the
regulator 69 to the air manifold 13 and its spray heads 15.
When the pressure of the air delivered to the spray heads
15 exceeds a certain fixed value, the pneumatic pressure-
operated electric switch 59 closes its normally open contactor 60completing an electrical circuit to the solenoid oE three-way
solenoid valve 62 to open the latter for supplying water at a
pressure governed by the regulator 68 to the spray heads 15. ThiC
water first enters the manifold 14 and then passes through the
A -14-
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tubes 36 to ~he spray l-ea~s 15 which operate as previously
described in connection with ~igure 2 oE the drawings.
In accor~ance wi~h the ~ain subject matter and main
improvement ~eature o~ the invention, the volumetric flow rate
ot water passin~ througll the spray heads 15, in o~her words, the
modulation of water flow through the spray heacls, is effected
directly by the pneumatic signal in the line 52, acting through
the reversing relay 43a and the line 43b and jumper lines 43c to
43e, etc. leading to the inlet fittings l9a and the rear control
air chambers 17a of the spray heads 15.
As the pneumatic signal to the rear chambers 17a of the
spray heads increases or decreases, it will counteract the water
pressure in the ~orward cl~amber 17 on the other side o~
diaphragm 18 to a greater or lesser degree. As the differential
between the control air pressure and the wa~er pressure increases
or decreases, it will cause the plunger 25 to move rearwardly or
forwardly, thus increasing or decreasing the water flow in the
particular spray head 15.
An increasing pneumatic pressure signal tllrough the line
52 results in a decreasing pneumatic pressure signal from
reversing relay 43a in lines 43b...ll3e, etc., which will cause
the plunger 25 to move rearwardly, allowing increased water flow
through the spray heads 15. With a decreasing pneumatic pressure
signal in line 52, the system mo~ulates downwardly, that is, the
pressure o~ control air in lines 43b...43e and in the rear
charnbers 17a is increased, causing the plungers 25 to move for-
wardly, thereby restricting water flow through the spray heads
15, whereby the water output from the spray heads is correspond-
A ingly diminislled.
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In the control system disclosed in the prior application,
an increasing pneulTIatic pressure signal through the line 52 was
utilized to open the rnodulating water valve, thereby increasing
water flow to the spray heads 15. In the present invention, the
increasing pneumatic signal in the line 52 is reversed by the
relay ll3a, and becomes a clecreasing control signal in the rear
chambers l7a oE ~he spray heads 15. This arrangement allows the
opposing or off-setting water pressure in the chambers 17 of the
- spray heads to increase the flow of water through the spray heads
accordingly. Irl other words, the decreasing pneumatic signal in
the chambers 17a will permit the plungers 25 to retract further,
permittillg increased water flow througll and from the spray heads
15. As stated previously, when the system modulates downwardly,
the pneumatic control pressure in the chambers 17a is increased
causing the plun~ers 25 to move forwardly to thereby restrict and
lessen the water flow through the spray heads as the plunger seal
27 moves closer to the seat 28.
In all other respects, the system operates in the sarne
manner described in the prior referenced application and retains
the advantages described in that application, plus the advantages
set forth herein derived from the much more sensitive and precise
direct air modulating arrangement.
The terms and expressions which have been employed herein
are used as terms of description and not of limitation, and there
is no intention, in the use of such terms and expressions, of
excluding any equivalents of the features shown and described or
portions thereof but it is recognized that various modifications
are possible within the scope of the invention claimed.
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