Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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COOLANT FED HUMIDIFIER HAVING SIPHON
DRAIN AND METHOD THEREFOR
[0002] The present invention relates to a coolant fed humidifier, particularly
cool water,
having a siphon drain.
BACKGROUND OF THE INVENTION
[0003] Many humidifiers generate water vapor for heat, ventilation and air
conditioning
(HVAC) systems by heating water to a boiling temperature and thereby suppling
airborne water
vapor to the HVAC system in a building. These types of humidifiers sometime
suffer from the
accumulation of minerals and other water bome particles or elements. In order
to continue the
efficient operation of this type of humidifier, the humidifier tank is
periodically flushed or filled with
water from a water supply or water source. Water from the source is usually at
a much lower
temperature, typically the ambient temperature, and hence, cooler than water
in the humidifier tank.
Accordingly, it is proper to call this water from the source "coolant" or
"cool water."
[0004] The control system which triggers the fresh water rinse can use many
parameters such
as periodic time frames, the amount of input water, seasonal drain cycles, the
number of times the
water in the humidifier exceeds a certain level or the amount of foam in the
humidifier. The present
invention can be utilized in conjunction with many types of control systems.
[0005] Government regulations in some jurisdictions now require that water
from the
humidifier tank only be discharged at or below a certain predetermined
temperature. In some
jurisdictions, the discharged water temperature may not exceed 140
Fahrenheit. The typical
temperature in a water humidifier is 212 Fahrenheit when the humidifier is
active.
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[0006] Accordingly, there is a need to provide a mechanism to chill or reduce
the
temperature of the water in the humidifier tank prior to discharging the water
from the tank.
[0007] Also, the cost of additional valving is a factor in the production of
humidifier
systems. The more valves utilized in a humidifier system, the higher the cost.
The utilization of
additional valves requires additional maintenance. Additional control
circuitry and control wiring
must also be employed with additional valves. Hence, there is a need for a
humidifier system which
lowers the tank water temperature to acceptable levels and automatically
flushes the system without
the need for additional valves and valve control systems.
[0008] Nothing in the prior art provides solutions to these problems. For
example, U.S.
Patent No. 3,612,033 to Chilcoat discloses a humidifier with a siphon draining
a drain off reservoir
which is distinct from the humidifier tank. U.S. Patent No. 3,716,043 to
Chilcoat has a similar drain
off reservoir.
[00091 U.S. Patent No. 3,643930 to Schulze discloses a humidifier tank fed
with source fluid
and an inverted U-shaped siphon drain from the tank. Source fluid, under
control, sometimes flushes
the tank by raising the fluid level in the tank above the height of the
inverted U-shaped siphon
thereby causing an automatic siphon drain of the tank fluid. U.S. Patent No.
3,739,597 to Schulze
has a similar automatic siphon.
[00101 U.S. Patent No. 4,243,396 to Cronenberg uses a siphon tube to draw up
liquid from
a lower liquid source.
[00111 U.S. Patent No. 4,705,936 to Fowler discloses an inverted U-shaped
siphon from a
boiling tank leading to an adjacent drain tank at the same level as the
boiling tank. The fill tube
feeding the boiling tank is distinct from the automatic siphon.
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Objects of the Invention
[00121 It is an object of the present invention to provide a coolant fed
humidifier having an
automatic siphon drain.
[0013] It is an additional object of the present invention to provide a
humidifier which is fed
with cooler source water, thereby reducing the tenlperature of the water in
the humidifier tank and
then automatically draining the tank water once the tank water exceeds a
predetermined level in the
tank.
[0014] It is a further object of the present invention to provide a humidifier
with an automatic
siphon drain thereby eliminating additional valves.
[0015] It is another object of the present invention to provide a humidifier
tank flusliing
system in which the humidifier tank water is admixed with cooler water,
thereby reducing the water
temperature of the admixture prior to siphoning and draining the water, and
that is also capable of
admixing additional cooler water into the admixture as it is being drained
through the siphon action
such that the new admixture resultant is yet at a lower temperature.
[0016] It is a further object of the present invention to provide a method of
draining a hot
water humidifier.
SUMMARY OF THE INVENTION
[0017] A hot water humidifier with an automatic siphon drain fed with cooler
source water
is flushed via a drain. The hot water humidifier includes a humidifier tank
supplied with the cooler
source water. The automatic siphon is an inverted substantially U-shaped
siphon conduit
automatically operable with respect to the humidifier tank having one end
coupled to the tank and
the other end coupled to the drain. The humidifier also includes a source
conduit coupled to and
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feeding the cooler source water to the humidifier tank. A valve controlling
the
cooler source water feeds the source water into the humidifier tank to
maintain
the temperature of an admixture of cooler source water and any pre-existing
tank water at or below a predetermined temperature during a flush cycle. The
tank is flushed and drained via the automatic siphon based upon the level of
the
admixture in the tank and the level of admixture in the siphon. The source
conduit which feeds water to the tank is coupled to the humidifier thank via
the
siphon conduit. The apex of the siphon conduit is positioned at a level above
the
end of the siphon conduit coupled to the humidifier tank. The source conduit
may also be coupled to the humidifier tank in more than one location to
promote
admixing of the cooler source water with the hot water in the tank. a
temperature
sensor may also be disposed within any of the areas containing the admixture,
including the tank and associated conduits, to provide feedback to the valve
controlling the input of source water into the system. In addition, cooler
source
water may be added to the admixture as it is draining during the siphon action
in
order to further lower the temperature of the admixture.
[0018] A method of draining a hot water humidifier having a humidifier
tank supplied with cooler source water is also included. The method comprises
admixing the cooler source water in the tank with the hot water until the
admixture reaches a predetermined siphon height and is less than a
predetermined temperature, and thereafter, automatically siphoning and
draining
the admixture until the admixture reaches a lower siphon exhausting height.
In a first embodiment of the invention as claimed, the method also
comprises adding said cooler source water downstream of said lower siphon
exhaustion height to further lower the temperature of said admixture.
In a second embodiment of the invention as claimed, the admixing
step includes adding said cooler source water downstream of said lower siphon
exhaustion height.
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BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Further objects and advantages of the present invention can be
found in the detailed description of the preferred embodiments when taken in
conjunction with the accompanying drawings in which:
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[0020] FIG. 1 diagrammatically illustrates the humidifier system fed with
source water and
having a siphon drain;
[00211 FIG. 2 diagrammatically illustrates an alternative arrangement ofthe
hydraulic system
for the siphon drain;
[00221 FIG. 3 diagrammatically illustrates the automatic siphon drain with a
one way valve
at the coolant supply; and
[0023] FIG. 4 diagrammatically illustrates an alternative embodiment of the
automatic
siphon drain system for hot water humidifiers.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0024] Further objects and advantages of the present invention can be found in
the detailed
description of the preferred embodiments when taken in conjunction with the
drawings.
[00251 The present invention relates to a humidifier fed with coolant or
cooler source water
and having a siphon drain. FIG. I diagrammatically illustrates humidifier
system 12 having a
humidifier tank 14. Tank water 16 is shown at level A in tank 14. I-leating
element 18 has an active
heating element segment 20. Humidifier tank 14 is typically stainless steel.
Water or coolant 16 is
typically fresh water. Heating segment 18 may include, in some embodiments, a
temperature sensor.
Typically, the control system for the humidifier utilizes float switches (not
shown) to detect upper
and lower tank water levels. Other water level sensors are available (e.g.,
electronic sensors 36).
100261 Tank 14 is supplied with liquid coolant 16, which is typically water,
and drained via
port 22 located at a lower part of the holding tank. In the embodiment
illustrated in FIG. 1, water
16 is supplied to the tank via water source intake 32. Intake or source
conduit 32 includes an air gap
coupting 38. Some jurisdictions have enacted building codes which require an
air gap be installed
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on all water supply valves connected to the municipal or commercially
available water system in
order prevent contamination of the drinking water supply through inadvertent
back flow.
Alternatively, a one-way valve or check valve 80 (see FIGS.3 & 4) may also be
used to prevent
water flow back into the water system. Of course, the backflow prevention
valve 80 is not a
requirement for system operation. Similar features are identified herein using
the same reference
characters throughout the specification.
[00271 In operation, water is fed from source 24 through valve 26 (typically a
solenoid valve)
via input pipe or conduit segments 28 and 30. Air gap coupling 38 of source
conduit 32 couples
input pipe segments 28, 30. In FIG. 1, intake or source conduit 32 is fluidly
coupled to holding tank
14 via siphon conduit 50. Siphon conduit 50 is an inverted, substantially U-
shaped conduit or tube
with an apex 42 and two substantially downwardly facing conduit segments or
legs 44, 46. The first
downwardly facing conduit segmeiit 44 is connected at its terminal end to T-
coupler 52. One side
of T-coupier 52 is fluidly coupled to port 22 via conduit or pipe segment 34,
and the other side of
T-coupler 52 is coupled to level sensor system 36. Fluid level sensor system
36 may be used to
monitor the level of fluid in tank 14 such that valve 26 is opened when the
liquid in tank 14 has
evaporated below a predetermined level. It may also be used to begin a flush
cycle of tank 14 as
discussed below. The second downwardly facing conduit segment 46 is fluidly
coupled to drain 40.
Drain 40 is located lower than the bottom of holding tank 14 and may be
connected to the sewer
drain system or a nearby drain field. In FIG. 1, The apex 42 of inverted U-
shaped siphon conduit
50 is positioned at a level below a top of the holding tank 14 such that the
siphon tube segment 44
may fill as the tank 14 is filled until the level of liquid in the tank
reaches the apex 42 whereupon
the siphon conduit 50 automatically begins siphoning liquid from tank 14 into
drain 40 via siphon
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conduit 50. Hence, the U-shaped siphon conduit 50 is automatically operable
with respect to the
humidifier tank 14 once the correct level of water is reached in the tank. In
another embodiment,
the apex 42 is at a level parallel with or slightly higher than the top of
humidifier tank 14 (FIG. 4).
The humidifier system 12 typically operates in connection with an HVAC system.
Accordingly the
steam or vapor output 10 and the remaining water 16 in the tank 14 are
subjected to the static
pressure P present in the air duct system. Hence, during operation of the HVAC
system, there may
be greater pressure P exerted within humidifier tank 14 than the atmospheric
pressure present within
siphon conduit 50. Accordingly, siphon conduit 50 may be designed with the
apex 421evel with or
slightly higher than the top of tank 14, and still remain automatically
operable with respect to the
level of fluid in tank 14. The top of humidifier 14 in FIG. 4 is not open to
atmospheric pressure, but
is closed and vented to the HVAC air duct system, subject to the system static
pressure P.
[0028) During a fill cycle under normal operation of the humidifier, valve 26
is opened,
allowing coolant water to flow through input pipe segments 28, 30, through
pipe segment 34 into
port 22, and ultimately, into humidifier tank 14. The water level A in tank 14
is monitored by the
water level sensor system 36 which is hydraulically linked to the hydraulic
piping connected at port
22. Water level sensor 36 can be one of various sensor systems as known to
those skilled in the art
and may be located directly in tank 14. Over time, as more and more water
evaporates, impurities
in the coolant water and other sediment accumulate at the bottom of the
holding tank 14 or are
suspended in the remaining hot water in the tank. During operation of the
humidifier, the water
temperature may reach 212 degrees Fahrenheit.
100241 When the remaining water 16 and tank 14 must be flushed and drained,
the remaining
water 16 should to be cooled to the required or predetermined lower
temperature. Some
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governmental agencies establish that the flush water should not exceed 140
Fahrenheit or some
other predetermined temperature. Other temperatures could be set by other
governmental agencies
or by HVAC engineers or contractors. In any event, water 16 in humidifier tank
14 is almost always
hotter, during regular humidifier operation, than the temperature of water
from source 24. When
necessary as described above, tank water 16 must be cooled to a lower
temperature prior to being
discharged into drain 40. Upon command by the control system, valve 26 is
opened and cooler
source water or coolant is fed into tank 14 via valve 26, pipe segments 28, 30
and pipe segment 34.
When the water in tank 14 reaches or exceeds predetermined level B (higher
than level A), the
temperature of the tank water should be at or below the prescribed
temperature. The system may
be designed such that a predetermined volume of cooler source water 24 is
admixed into the tank
14 to bring the resultant admixture within a predetermined, acceptable
temperati_Lre limit. Variables
to determine the amount of water to admix may include the tank dimensions, the
volume of water
capable of flowing into the tank 14 and the temperature/volunie of normal
operating water quantities.
A temperature sensor 70 (FIG. 4) may also be used to control the quantity of
cooler water admixed
into tank 14. The cooler water from source 24 admixes with the hotter water 16
in tank 14 creating
a lower temperature admixture of liquid. The admixing also functions to stir
the water 16 in the
tank, thus temporarily suspending accumulated sediment and particles at the
bottom of the tank 14.
When the admixture reaches water level B and begins to exceed the height of
siphon top or apex 42
of siphon conduit 50, a siphon action is created with the formation of the
column of water in siphon
segment 46. Siphon conduit 50 is an inverted U-shaped pipe fluidly coupled to
the bottom of tank
14 via pipe segment 34 and subsidiary segment 45. The siphon action continues,
draining the
admixture in tank 14 into drain 40, until the water reaches lower tevel C
which is generally at the
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level of port 22. In this manner, there is no need for an additional drain
valve. This reduces the cost
of the system and potentially reduces maintenance of the system.
j0030] To describe the operation of the system in a different manner, when the
admixture
of hot water in tank 14 and the cooler source water exceeds the siphon height
(at or exceeding level
B) at the top of the inverted U-shaped siphon, the system automatically drains
the tank water by
siphon action. The height of the siphon or siphon apex 42 may be determined
upon the volume of
water required to bring the admixture in the tank 14 within an acceptable
upper temperature limit.
In the embodiments illustrated in FIGS. 1 and 2, the apex 42 of siphon conduit
50 is located at or
below the top of the tank 14. However, as illustrated in FIG. 4, the apex 42
of siphon conduit 50
may be higher than the top of tank 14 in systems exposed to the HVAC static
pressure P present in
the duct system which is higher than the normal atmospheric pressure present
at the discharge side
46 of siphon conduit 50.
[0031,1 One advantage of the embodiment illustrated in FIG. 1 is the ability
to regulate the
temperature of the admixture being drained into drain 40. If, based upon the
operating parameters
and the size of the tank, the temperature of the admixture drain water is not
at or below the
predetermined low discharge temperature level, or it is desirable to lower the
temperature of the
admixture resultant further, source water may be added to the automatic siphon
discharge by
partially or intermittently opening valve 26 and adding cool source water to
the warmer drain water.
The addition of source water to the drain water will reduce the temperature of
the drain water at or
below the prescribed level as it is being removed through siphon conduit 50.
Valve 26 could be
partially ON, fully ON or pulse width modulated (PWM), that is, ON/OFF for
predetermined time
periods, until the drain water is at or below the predetermined temperature.
The addition of source
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water 24 to the output drain water is possible as long as the source fluid
flow is less than and no
greater than the siphon drain flow through the inverted U-shaped siphon
conduit 50. Port 22 is
effectively the exhaustion height of the siphon drain because, when water 16
is at or below height
C, the siphon is broken or "exhausted" and therefore stops draining water
through the inverted U-
shaped drain siphon tube 44.
[0032] Water flow in inverted U-shaped siphon conduit or piping segment 50
flows in
direction 60. Cool source water flows in direction 62. Water flows in both
directions through
conduit segment 34 based upon whether valve 26 is open thereby permitting the
input of source fluid
into humidifier tank or based upon the siphon action through siphon conduit 50
in direction 60.
Fluid flow through pipe segment 45 follows direction 60 in the siphon conduit
60.
[0033} FIG. 2 diagrammatically illustrates the automatic siphon system 12 in
which the
coolant water source 24 is fluidly coupled to tank 14 via coolant source
intake 32 which has two air
gap couplers 38a, 38b disposed atop tank 14. As illustrated, this embodiment
promotes a vigorous
mixture of the hot fluid in the container 14 with the new coolant being added.
The system 12
illustrated in FIG. 2 works in substantially the same manner as the system in
FIG. 1, with the
exception of the how the coolant source water reaches tank 14. A hybrid of the
two embodiments
may also be implemented in which a segment of pipe fluidly coupled to pipe
segment 28 allows
source water 24 to be added directly into pipe segment 45 such that the
addition of coolant water at
pipe segment 45 effectively brings down the temperature of the drain water
being drained through
siphon conduit 50 during a flush cycle.
FIG. 3 diagrammatically illustrates an alternative embodiment of the automatic
siphon drain
system 12. A one-way valve 80 is used rather than air gap coupling 32 to
connect conduit section
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28 and conduit section 30 leading to intermediate conduit 34 and ultimately to
port 22 and tank 14.
One-way valve 80 may be a check valve or flapper valve as is known to those of
skill in the art.
FIG. 4 diagrammatically illustrates the automatic siphon drain system 12 with
a temperature
sensor 70 disposed within holding tank 14. The admixture temperature sensor 70
may be disposed
anywhere within the system such that the sensor is exposed to the admixture
resultant. For example,
sensor 70 may be disposed within conduit segments 34 or 44. The temperature
sensor 70 is coupled
to a valve actuator 74 at coolant supply 24 via feedback line 72. The valve
actuator 74 may also be
a solenoid valve. Feedback line 72 provides the valvc actuator 74 feedback on
whether the
temperature of the admixture in tank 14 requires more coolant. Feedback line
72 may also be
coupled to HVAC controls via line 76. In FIG. 4, port 22 is located at the
bottom of the tank 14,
thus promoting a thorough flush of the tank during a cleaning cycle. In this
embodiment, heating
element 18 should be turned off during the flush cycle to avoid overheating of
the element.
The embodiment illustrated in FIG. 4 includes a siphon conduit 50 having its
apex 42 at a
level slightly higher than the top of tank 14. This configuration is possible
because of the higher
static air pressure P present in tank 14 as a result of the static pressure P
in the air ducts of the HVAC
system. The steam or vapor output 10 and the water 16 in tank 14 are subjected
to the air duct static
air pressure P. During operation of the HVAC system, the greater air pressure
(in comparison to the
atmospheric air pressure present in conduit segment 46) exerted within
humidifier tank 14 causes
the water level 56 in siphon conduit segment 44 to rise higher than the water
level in tank 14.
Accordingly, the automatic siphon action will occur even though the water
level in tank 14 is lower
than the admixture water level in siphon conduit 50.
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[0034] The claims appended hereto are meant to cover modifications and
changes within the scope and spirit of the present invention.
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