US20140203459A1

US20140203459A1 - Steam humidification system

Info

Publication number: US20140203459A1
Application number: US13/746,175
Authority: US
Inventors: Zev W. KOPEL; Eric Landry; Antonio Di-Fruscio
Original assignee: National Environmental Products Ltd
Current assignee: National Environmental Products Ltd
Priority date: 2013-01-21
Filing date: 2013-01-21
Publication date: 2014-07-24

Abstract

A steam distribution apparatus having a heat exchanger header defining a chamber; steam distribution apparatus communicating with the heat exchanger chamber; a source of steam at a pressure higher than atmospheric; a heat exchanger having one end communicating with the source of steam and another end for communicating with the chamber and steam dispersion apparatus; and a valve. The valve operates the heat exchanger in an open-loop configuration which supplies humidification steam to the steam distribution apparatus at atmospheric pressure and operates the heat exchanger in a closed-loop at the steam pressure higher than atmospheric for heating the heat exchanger chamber wherein condensate within the chamber or steam distribution apparatus can be converted back to humidification steam.

Description

FIELD OF INVENTION

This invention relates to steam dispersion humidification and in particular relates to a steam dispersion system, apparatus and method of humidifying air having a combined open and closed loop system. More specifically the invention relates to a steam dispersion system having steam dispersion pipes, a source of steam at a pressure higher than atmospheric and a steam header having one end communicating with the source of steam and another end supplying humidification steam to the steam dispersion pipes.

BACKGROUND TO THE INVENTION

Most modern commercial and industrial buildings are equipped with steam humidifiers mounted within the heating and air conditioning systems. Steam from the steam boiler, district steam system or steam generating humidifier is introduced into a ducted air stream and distributed throughout the building. Generally speaking, it is not advisable to allow humidification steam to condense into water in a duct system as such damp areas can become breeding grounds for algae, bacteria and organic contamination.
There have been a variety of steam humidification systems, apparatus and methods that have heretofore been developed in order to control condensate. For example, US Publication US2009/0121367 relates to a steam dispersion apparatus having a steam chamber communicating in an open-loop arrangement with a first steam source for supplying steam to the steam chamber, which steam chamber includes a steam dispersion location at which steam exits therefrom at atmospheric pressure. The heat exchanger communicates in a closed loop arrangement with a second steam source for supplying steam to the heat exchanger at a pressure higher than atmospheric pressure to convert condensate formed by the steamer chamber back to steam when the condensate contacts the heat exchanger.
Another arrangement is illustrated in U.S. Pat. No. 5,516,466 which relates to a steam humidification system comprising a manifold for receiving steam and at least one steam dispersion tube extending from the manifold for receiving steam. U.S. Pat. No. 6,065,740 shows a steam distribution device for a steam humidification system comprising a horizontally mounted steam dispersion element for receiving steam from the source of steam and for dispersing a portion of the steam into an air stream.
Moreover, U.S. Pat. No. 6,227,526 illustrates a steam dispersion device for a steam humidification system which includes a source of steam, a horizontally mounted steam dispersion element for receiving steam from the source of steam and for dispensing a portion of the steam into an air stream, a horizontally mounted jacket partially surrounding the steam dispersion element and unconnected to the source of steam for maintaining the temperature of the steam dispersion element at or about the temperature of the steam.
U.S. Pat. No. 4,913,856 relates to a humidifier system where atomized water is caused to be rapidly evaporated as a result of being strategically located in the path of high velocity turbulent air created by converging deflector vein sets. Yet another arrangement is shown in U.S. Pat. No. 5,543,090 which relates to apparatus for introducing steam into an air stream in an HVAC system which includes a supply header-steamed dispersing structure and structure reflecting condensate from the steam dispersing structure.
Moreover, U.S. Pat. No. 6,065,740 relates to a steam distribution device for a steam humidification system. U.S. Pat. No. 6,227,526 relates to a steam distribution device for a steam humidification system which includes a source of steam, a horizontally mounted source of steam dispersion element for receiving steam from the source of steam and for dispersing a portion of the steam into an airstream.
U.S. Pat. No. 6,488,219 shows a steam humidifier with pressure variable aperture. Also, U.S. Pat. No. 6,631,856 illustrates a humidifier for providing moisture to an airstream which comprises a pipe having a first end for connecting to a source of steam end a closed second end; first and second slots disposed opposite each other and longitudinally along a major portion of the length of the pipe; and a plurality of members sandwiched within the first and second slots, the members being disposed toward the interior of the pipe to guide condensate into the interior of the pipe. Also U.S. Pat. No. 7,980,535 teaches a demand activated steam dispersion system.
Moreover, there are various prior art devices and methods which illustrate a variety of steam distributors or pipe. For example, U.S. Pat. No. 4,265,840 teaches a vapour distributor pipe for an air humidifier.
Furthermore, U.S. Pat. No. 5,126,080 relates to apparatus for introducing steam into an air stream in a heating, ventilating and air conditioning system which includes a supply header, steam distributing structure and structure for collecting condensate from the steam distributing structure. This patent also illustrates a variety of distributor pipes. Also, U.S. Pat. No. 5,372,753 illustrates an apparatus for introducing steam into an air stream in an HVAC humidification system which illustrates distribution pipes disposed in a vertical orientation.
The prior art also discloses a variety of different apparatus and methods for insulating the distribution apparatus in an effort to minimize condensate. For example, U.S. Pat. No. 7,744,068 teaches a distribution system which includes insulation where the insulation covers at least a portion of the steam dispersion tubes, the insulation defining an opening aligned with the opening of the steam dispersion tube where the insulation meets 25-50 flame/smoke indices for UL 273/ASTME-84 and has a thennal conductivity less than about 035 Watts/n-K (2.4 in/hr/st2deg Fl. The insulation includes polyvinylidene flouride.
Moreover, U.S. Pat. No. 8,092,729 relates to a method of attaching insulation to a steam dispersion tube where the insulation includes polyvinylidine flouride.
These and other prior art systems, apparatus and method relating to humidification dispersion systems present relatively complicated structures. Moreover, the dispersion pipes and insulation methods and systems present relatively complicated structures.

OBJECTS OF THE INVENTION

Accordingly, it is an object of this invention to provide an improved steam dispersion system, apparatus and insulation as compared to the prior art.

SUMMARY OF THE INVENTION

It is an aspect of this invention to provide a steam dispersion system comprising steam dispersion apparatus, a source of steam at a pressure higher than atmospheric, a steam header communicating with the source of steam and operable in a closed and open loop for supplying humidification steam to the steam dispersion apparatus configured to provide humidification steam to the air in the open loop, and inhibiting the fonnation of condensate in the steam dispersion system in the closed loop. The steam in the heat exchanger is at a pressure higher than atmosphic, while the pressure in the dispersion apparatus is at atmospheric pressure.
It is another aspect of this invention to provide steam distribution apparatus comprising a heat exchanger header defining a chamber, a steam distribution apparatus communicating with the heat exchanger chamber, a source of steam at a pressure higher than atmospheric, a heat exchanger having one end communicating with the source of steam at a pressure higher than atmospheric, and another end of the heat exchanger for communicating with the chamber and steam dispersion apparatus at atmospheric pressure; a control valve for operating the heat exchanger header in an open-loop for supplying humidification steam to the steam distribution apparatus at atmospheric pressure; an isolating valve operating in a first preheat stage to preheat the heat exchanger, heat exchanger header.
It is a further aspect of this invention to provide a method of humidifying air using steam comprising supplying a source of steam at a pressure above atmospheric pressure to a heat exchanger disposed within a header defining a chamber wherein the chamber communicates with steam distribution pipes communicating with the air at atmospheric pressure; isolation valve for supplying the steam to the heat exchanger at a pressure above atmospheric to heat the chamber in a closed-loop, and a controller valve supplying steam to the chamber and distribution pipes to supply humidification steam to the air.
Still another aspect of the invention relates to a steam dispersion system comprising: steam dispersion apparatus; a source of steam at a pressure higher than atmospheric; a heat exchanger communicating with the source of steam and operable in a closed and open loop; an isolating valve to pre-heat the heat exchanger in a pre-heat closed loop cycle and act as a re-evaporator of condensate in a humidification cycle (when the steam control valve is in the humidification cycle); a steam control valve to operate the steam dispersion system in an open-loop having a pre-heat cycle so as to inhibit condensate formation followed by a control cycle to provide controlled humidification.
Yet another aspect of the invention relates to a nozzle for steam dispersion tubes, the nozzle comprising a body extending longitudinally about a generally cylindrical axis; a hole through the body whereby the hole has an axis disposed at an acute angle relative to the cylindrical axis to assist in discharging any condensate by gravity.
Another aspect of the invention provides insulation for a steam dispersion tube having an outer wall with a plurality of aligned nozzles, said insulation disposed about said outer wall where the cross section of said insulation in the vicinity of the nozzles is less than the cross section of the insulation remote from said nozzles.
These and other objects and features of the invention will now be described in relation to the following drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of one embodiment of the steam dispersion system.

FIGS. 2 a, 2 b, and 2 c, are side views, elevational view, and exploded view respectively of the steam dispersion system shown in FIG. 1.

FIGS. 3 a and 3 b are actuated steam control valve operating sequence charts in a pre-heat stage and a controlled stage respectively.

FIG. 4 is a schematic view of another embodiment of the invention.

FIGS. 5 a, 5 b, 5 c are elevational, front elevational and exploded views of the embodiment shown in FIG. 4.

FIG. 6 is a perspective view of the embodiment shown in FIGS. 4, 5 a, 5 b and 5 c.

FIG. 7 is another perspective view of FIG. 6.

FIGS. 8 a, 8 b, 8 c are schematic side elevational views, another side elevational view, and a exploded view, respectively, of another embodiment of the invention where the distribution tubes are in a horizontal orientation.

FIG. 9 is a side elevational view showing insulation on the steam distribution tubes.

FIG. 10 is a front view of a nozzle.

FIG. 11 is a cross sectional view of FIG. 10.

FIG. 12 is a cross sectional view of one nozzle.

FIG. 13 is a top plan view of another embodiment of the invention showing the insulation

DETAILED DESCRIPTION OF THE INVENTION

Like parts are given like numbers throughout the drawings and description herein. In the drawings, embodiments of the invention are illustrated by way of example. It is to be expressly understood that the description and drawings are only for the purpose of illustration and as an aid to understanding, and are not intended as a definition of the limits of the invention.
FIGS. 1 and 2A, 2B, 2C illustrate one embodiment of the invention. In particular, the FIGS. 1 and 2 illustrate a steam distribution system 2 which includes steam dispersion apparatus 4 as generally illustrated in the drawings of the description herein. FIGS. 1 and 2 illustrate the steam distribution tubes 12 in a vertical orientation.
In particular, the steam distribution apparatus 4 includes a steam header 6, a heat exchanger 8 and the piped assembly apparatus as shown in the drawings. The steam header 6 can comprise of a variety of materials including sheet metal, steel, iron, cast iron, copper or the like. The steam header 6 can be made from two or more pieces so as to permit the insertion of the heat exchanger 8 within a steam header chamber 11. The heat exchanger 8 as disclosed in FIG. 1 can be made from a one piece hollow copper tube having a primary steam inlet 32 and a steam outlet 34. The heat exchanger 8 can also be made from stainless steel, copper, sheet metal, iron, cast iron or the like.
The steam distribution apparatus 4 also includes a steam source 50 with a primary steam supply line 9 that communicates with the primary steam inlet 32 that will communicate with the heat exchange chamber 10 so as to heat up the heat exchanger 8 and header 6. Thereafter steam will exit the steam outlet 34 toward a steam separator 26. The steam separator 26 separates the steam 25 into two paths namely S1 and S2. The steam S1 communicates with the steam supply pipe 10 that feeds the steam injector 40 disposed in the header 6 as shown in FIG. 1. The steam injector 40 includes a plurality of exit steam holes 16. In one embodiment, the exit steam holes 16 are disposed so as to face the heat exchanger 8 so that if there is any condensate in the steam S1 exiting the exit steam holes 16, the condensate will drop onto the heat exchanger 8 by force of gravity so as to be re-vapourized as steam.
The steam distribution apparatus to be described herein has been designed so as to minimize the presence of condensate and thereby provide a more efficient steam distribution system 2 and apparatus 4.
In the embodiment shown in FIG. 1, the heat exchanger 8 is made of one large diameter copper tube. The heat exchanger 8 has a larger diameter than the steam carrying supply line 9 so as to carry sufficient energy to evaporate the condensate formed in the steam distribution tubes 12 and to evaporate internal condensate of the heat exchanger 8.
FIGS. 1 and 2A, 2B, 2C illustrates a horizontal application of the steam header 6. The heat exchanger 8 is placed directly under the steam holes 16 of steam injector 40 of the vertical steam distribution tubes 12 in such a manner as to ensure that the condensate from the steam distribution tubes 12 falls on the upper portion of the heat exchanger 8.
The control steam supply pipe 10 (see port 43) coming from the actuated steam control valve 18 will be connected to the steam injector 40 placed above the heat exchanger 8 so that any residual condensate in that pipe will fall on the upper part of the heat exchanger 8.
In particular part of the steam injector 40 can also extend into the steam header 6 and will include exit steam holes 16 pointing downwards toward the heat exchanger 8 in such a manner so as to have any residual condensate after the actuated steam control valve 18 fall on the upper part of the heat exchanger 8.
The heat exchanger 8 has in one embodiment a construction comprised of an inlet primary steam supply pipe 9 which communicates with the isolation valve 20 directly into the heat exchanger 8 by connecting the primary steam inlet 32.
As best illustrated in FIG. 2A, the bottom surface 31 of the header 6 includes angled surfaces 30 to bring the condensate to close proximity of the heat exchanger 8 as well as reduce the surface area of the header 6 in order to reduce energy loss.

Operation Description

The controller 60 can comprise of a variety of devices including computers, micro processors, or the like. In one embodiment, the controller 60 can be wired to the various steam distribution apparatus 4 as described in this application or it can communicate wirelessly with the steam distribution apparatus 4 both in sending and receiving signals therefrom.
In one embodiment of the invention, the temperature range of the distribution apparatus 4 can be pre-programmed in the controller 60.
The controller 60 reads the temperature at the upstream temperature sensor 22 and compares it to a pre-determined range of operational temperatures. The temperature range can be derived from the system's steam pressure.
The isolating valve 20 can be programmed to fully open only if the temperature at sensor 22 falls within the pre-determined temperature range. The steam from source 50 will then heat up the heat exchanger 8 and the steam separator 26 and the temperature sensor 24 downstream of the heat exchanger 8. When the temperature at the temperature sensor 24 is within a pre-determined selected temperature range, the actuated steam control valve 18 opens at a controlled opening speed and to a pre-determined or selected pre-heat partial opening of the valve 18.
The actuated steam control valve 18 will remain in this position for a pre-determined heating delay, or cycle. Accordingly, the slower opening of the actuated steam control valve 18, the partial opening of the actuated steam control valve 18 and the delay period are forced or controlled by the controller 60 in order to ensure controlled pre-heat of the atmospheric section of the apparatus to be described herein and thus preclude sudden formation of condensate and the resulting ejection of that condensate through the steam distribution tubes 12 into the air ducts.
After the controlled pre-heat cycle of the atmospheric section of the apparatus 4 the actuated steam control valve 18 will then assume its normal control function responding to the actual humidification demand from a humidistat (not shown) by means of the controller 60.
If at any time the temperature read by temperature sensor 24 downstream of the heat exchanger 8 and or at the upstream temperature sensor 22 drops under the selected preset required temperature range, the actuated steam control valve 18 will close at maximum speed, leaving the isolation valve 20 open so as to raise the temperature.
When the humidity demand is satisfied, the actuated steam control valve 18 will close and after a pre-determined delay, the isolating valve 20 will also close. This will allow substantially all the condensate to be re-evaporated by the heat exchanger 8.

Automation

The temperature range of operation is selectively preset in the controller 60 by means of the steam supply pressure in accordance with thermodynamic laws where the steam temperature can be determined by a person skilled in the art.
The low temperature and high temperature of the temperature range may be selectively set in the controller 60 according to these thermodynamic laws; as well as taking into account cumulative errors including errors in sensor readings. For example, the following illustrates one particular setting, although other settings can be selected.
Sensor error has been included above since the sensor in one embodiment can be a brass thermo where the read temperature differs from about 5 degrees celsius from the real temperature value.

Real Temperature Range (Self-Adjusting to any System Supply Pressure)

By using the temperature read at the temperature sensor upstream of the isolating valve 20, the steady state temperature can in one embodiment be determined and recorded in the controller. In this case, the temperature must remain constant with +/−0.5 degrees centigrade for 20 seconds in one of the embodiments of the invention. The recorded temperature will then be the steam temperature (from thermodynamic laws)−sensor error.
The sequence described above automates the humidifier temperature range operation for any steam supply. The humidifier will properly work even if the steam pressure is unknown by the user and the manufacturer. In other words, the system described herein is self-adjusting to the temperature range.

Actuated Steam Control Valve Opening Sequence

FIG. 3 a illustrates one embodiment of an actuated steam control valve opening sequence. In particular FIG. 3 a illustrates a pre-heating stage having two time frames, namely the first preheating time frame from 100 to 102 and a second pre-heating time frame from 102 to 104.
The actuated steam control valve 18 opens at a pre-set opening speed POS until the pre-heating valve position PVP has been reached. This represents the first pre-heating time frame 100 to 102 and the slope 99 in FIG. 3 a represents the pre-set opening speed POS. The steeper the slope 99 the faster the speed. Once in the pre-heating valve position PVP, steam control valve 18 remains in that position for a certain predetermined period of time namely the heating time delay HTD represented by the second time frame 102 to 104. After the maximum heating time delay HTD marked by 104 in FIG. 3 a, the actuated control valve 18 will move at a constant opening speed or faster closing speed to a position detennined by a proportional signal coming from the controller 60.
The pre-heating stage 100 to 104 inhibits the fonnation of condensate “spitting” within the system.
FIG. 3 b is a representation of the controlled humidification stage which occurs after the preheat stage 104.
After the pre-heat stages 100 and 104 the controller 60 switches from pre-heat operation to control operation based on the humidification demand from the humidistat sensor and sends the proportional demand signal to the control actuated valve 18. The actual humidity in the duct work or in the space to be humidified is read by the humidistat sensor, that communicates with the controller 60. If the humidification demand is lower than the humidity reading by the humidistat sensor, the actuated control valve 18 will close to the proportional position as might be represented by the line 104 to 105. The slope 107 represents the speed of closure of the valve 18.
In one embodiment of the invention normal control speed has a faster closing than opening speed.
If the humidity demand is higher than the humidistat reading the controller 60 will further open the control valve 18 to the proportional position as might be represented by the line 104 to 103. The valve 18 will open at a pre-determined speed as represented by the slope of line 104 to 103. Line 103 to 105 represents closing of the steam control valve 18; and as previously stated occurs at a faster speed than opening. Thus the slope 109 is steeper.
It is possible that the humidity demand is the same as the humidistat reading in which event the steam control valve 18 will remain in its last position.

Humidifier Automated Operation

Once there is steam demand the following steps are implemented:

- 1. The controller 60 verifies that if the temperature of the upstream temperature sensor 22 upstream of the isolating valve 20 is at the proper pre-selected level. The temperature range as described above depends on the system steam pressure. The system pressure will determine which temperature the steam will be supplied.
- 2. Upon receiving a signal from controller 60 for humidification demand, isolating valve 20 will fully open only if the measured temperature at the temperature sensor upstream 22 of the isolating valve 20 which is read by the controller 60 is sufficiently high and is within the predetermined range.
- 3. Upon receiving a signal from controller 60 for humidification demand, isolating valve 20 will open and the steam from the steam source 50 will heat up the heat exchanger 8, the steam separator 26 and the temperature sensor 24. When the temperature at the downstream temperature sensor 24 is within the temperature range selected; the actuated steam control valve 18 will start the pre-heat cycle by opening to pre-determined pre-heat position at the preset opening speed. It will stay in the pre-heat position for pre-heat delay time.
- 4. The actuated steam control valve 18 will remain in pre-heating valve position for the predetermined heating delay which is typically between 20-30 seconds as an example of one embodiment. This will allow the steam distribution system 2 to heat up without ejecting condensate through nozzles 75 so as to minimize condensate spitting.
- 5. Then the actuated steam control valve 18 will assume normal proportional control function.
- 6. At any time, any of the temperature sensors 22 or 24 drop under the preset required temperature range, the actuated steam control valve 18 will close at maximum speed, leaving the isolating valve 20 fully open.
- 7. When there is no more call for humidity, the steam control valve 18 will close and after a preset delay, typically 30 seconds as an example, the isolating valve 20 will also close. This will allow all the condensate to be re-evaporated by the heat exchanger.

The controller 60 communicates with inputs from upstream temperature sensor 22, downstream sensor 24, and humidistat. Controller 60 controls or sends an output to steam control valve 18 and isolating valve 20. Communication between controller 60 and the various devices is either by direct wire connection (not shown) or by wireless means in a manner known to persons skilled in the art.
It will be appreciated by a person skilled in the art the vertically orientated distribution tubes 12 are disposed within a duct of an HVAC system. Accordingly, the distribution tubes will be disposed in a generally atmospheric pressure duct system. The steam from the source 50 is typically at a 3-15 psi pressure at 105-121 degrees centigrade respectively. However, the system can operate above 15 psi and the temperature of the steam can also be at other operating temperatures if operated with the invention as described.
Accordingly, the system 2 as described herein warms up the steam distribution apparatus 4 so as to substantially eliminate the condensate. Generally speaking the condensate if injected into the duct work within a HVAC system promotes the breeding of bacteria and viruses or the like which is an undesirable condition.
Furthermore, the actuated steam control valve 18 is moved (ie opened) to the pre-heating valve position PVP so as to wann up the distribution pipes 12 prior to nonnal modulating or control operation of the humidifier output. At nonnal control operation the output is proportional to the signal sent to control valve 18 from controller 60.
FIGS. 1 and 2A, 2B, 2C also illustrate a steam trap with a vacuum breaker 28.
Furthermore, another embodiment of a horizontally disposed steam header 6 is illustrated in FIGS. 4 and 5 a, 5 b, and 5 c.
FIGS. 4, 5 a, and 5 b generally include the same steam distribution apparatus as described in FIGS. 1 and 2A and operate in the same fashion except that the steam header 6 and heat exchanger 8 are constructed in a slightly different fashion.
The steam header 6 includes a portion of the primary steam supply line 9 inside the steam header 6 which loops around to communicate with an internal end 3 of the heat exchanger 8. This heat exchanger 8 also includes an exterior steam outlet 34.
Furthermore, the header 6 also includes angled surfaces 30 as previously described so as to force any condensate in closer proximity to the heat exchanger 8 by gravity.
Furthermore, the top ends of the vertical steam distribution tubes 12 include a V-shaped channel 13 so as to fasten the ends of the vertical distribution tubes 12 by means of fasteners 15 and rigidify the apparatus.
Furthermore, FIG. 5 c includes an exploded view of the exit steam ejector or steam nozzles 75 which are hollow and disposed within the interior of the vertical steam distribution tubes 12.
FIG. 6 is a perspective view of the embodiment shown in FIGS. 4 and 5A, 5B and include flanges 70 a having a plurality of holes 72 adapted to be fastened to a duct system (not shown). Furthermore, the steam header 6 can be comprised of two parts 6 a and 6 b (see FIG. 5A) so as to accommodate the insertion of the heat exchanger 8 along separation lines 7.
FIG. 7 shows another perspective view of the second embodiment disclosed in the FIGS. 4 and 5.
The operation of the embodiment shown in FIGS. 4, 5, 6, and 7 is similar to that illustrated to FIGS. 1 and 2.
The steam distribution apparatus as illustrated in FIGS. 1-7 generally illustrate the distribution tubes 12 in a vertical orientation. In other words, the distribution tubes 12 are generally disposed perpendicular to the steam header 6. The steam header illustrated in FIGS. 1-7 can also in certain applications be disposed in a perpendicular fashion whereby the steam distribution tubes 12 would be substantially parallel.
FIGS. 8 a, 8 b, and 8 c illustrate another embodiment of the invention whereby the steam header 6 is disposed in a vertical position and the horizontal steam distribution tubes 19 are disposed in a generally horizontal disposition relative to the steam header 6. More particularly, the horizontal steam distribution tubes 19 are disposed at an acute angle a such that any condensate within the tube 19 will float downwardly toward the frustoconical collectors 23 as best illustrated in FIG. 8 c.
The frustoconical collectors 23 are fastened to the outside surface of the heat exchanger 8 by press fit, soldering, welding, fasteners or the like. The heat from the outside of the heat exchanger 6 will re-vapourize any condensate 29. A plurality of frustoconical collectors 23 are disposed along the outside surface of the heat exchanger 8 as illustrated in FIGS. 8 a, 8 b, and 8 c. Furthermore the upper surface of the frustoconical collectors can include holes to permit the buildup of any condensate to fall to the next lower collector 23.
Furthermore, FIG. 9 illustrates a steam distribution tube 12 which has insulation 90 so as to further discourage the formation of condensate.
Moreover, FIG. 10 also illustrates that the nozzle 7S comprises a generally cylindrical body 73 presenting a cylindrical body axis. The body 73 having a hole 77 therethrough. The hole 77 has a hole axis 71 disposed at an acute angle b (FIG. 12) relative to the body axis whereby any condensate within the hole 77 of the nozzle 7S will flow downwardly toward the heat exchanger 8 as illustrated in FIG. 1.
Furthermore, FIG. 11 is a top plan view of FIG. 10.
Moreover, FIG. 13 illustrates a top plan view of a vertically disposed steam distribution tube 12 having insulation 90 which has been engineered to minimize formation of any condensate. In particular, the insulation 90 is thinnest in the vicinity of the nozzles 75 and thickest in the region furthest away from the nozzles 75. In one particular embodiment shown in FIG. 13, the insulation is oblong and cross-sectioned. In particular, the insulation 90 has an oblong outside diameter and a circular inside diameter.
The invention described herein has a number of advantages:

- 1. The insulation is thicker in the front and back where most of the heat loss occurs.
- 2. Furthermore, the shape of the insulation has better aerodynamic features so as to lower the static pressure loss. Every interference with the pressure of the steam drops the pressure and airflow and therefore requires more horsepower to compensate for this loss.
- 3. The nozzle 75 could be made of silicone rubber and is configured to bring the condensate at the cold startup back to the distributor. The inside slope improves such feature. Furthermore, the insulation 90 slips onto the stainless steel tubes forming distribution tubes 12 and 19 so as to perform insulating characteristics on the steam distributor. Furthermore, the shape of the insulation is designed to increase the efficiency without reducing the effective airflow section. The shape also reduced the pressure drop acting like a diverter instead of a baffle. More particularly, on the sides the thickness of the insulation 90 is reduced to avoid blocking the airflow section and also to reduce the nozzle thickness, thereby reducing condensate buildup and cold startup, thus again minimizing spitting of condensate.

The material used for the insulation is silicone foam rated UL723 and also UL94 VI. The foam reduces at maximum the heat transfer increasing the efficiency of the humidifier. The steam distribution system 2 and steam distribution apparatus 4 described herein includes the following advantages:

- 1. A closed/open loop system where the heat exchanger is in a closed system and the steam injector is in an open system.
- 2. The heat exchanger has a diameter substantially larger than the steam carrying parts.
- 3. Any condensate from the steam distribution pipes 12 and 19 fall directly onto the heat exchanger 8.
- 4. Steam injector 40 is forced to send steam and condensate directly onto the heat exchanger 8.
- 5. The angled bottom 30 of the steam header 6 force condensate into close proximity of the heat exchanger 6.
- 6. The arrangement in the horizontal application of the steam header 6 having trustoconical collectors or cups to collect the condensate on the heat exchanger.
- 7. There is no drain of condensate needed since all condensate is moved back into the boiler (not shown), or re-evaporated.
- 8. The controller 60 ensures an automatic startup.
- 9. The actuated steam control valve 18 is operated at two distinct speeds determined by the controller 60; namely, startup speed (very slow in order not to create spitting of condensate from the steam distribution tubes) and operational modulating speed for operation mode.
- 10. There is an automatic response to sudden pressure drop and energy conservation in the off mode.

Claims

1. A steam dispersion system comprising:

a. steam dispersion apparatus;

b. a source of steam at a pressure higher than atmospheric;

c. a heat exchanger communicating with the source of steam and operable in a closed and open loop for:

i. supplying humidification steam to the steam dispersion apparatus configured to provide humidification steam to the air in the open loop;

ii. inhibiting the formation of condensate in the steam dispersion system in the open loop.

2. The steam dispersion system as claimed in claim I, including a steam header defining a heat exchanger chamber communicating with the steam dispersion apparatus.

3. The steam dispersion system as claimed in claim 2, wherein the steam dispersion apparatus includes steam supply lines communicating with the heat exchanger and steam dispersion tubes when the cross section of the heat exchanger is equal to or larger than the cross section of the steam supply lines and steam dispersion tubes.

4. The steam dispersion system as claimed in claim 3, wherein any condensate from the steam dispersion tubes falls onto the heat exchanger.

5. The steam dispersion tube as claimed in claim 3, wherein a steam injector delivers steam and any condensate onto the heat exchanger in the steam header.

6. The steam dispersion system as claimed in claim 5, wherein the steam header has an angled bottom to direct any condensate into close proximity of the heat exchanger.

7. A steam dispersion system as claimed in claim 3, further including a controller.

8. A steam dispersion system as claimed in claim 6, wherein the steam dispersion tubes are either in a horizontal or vertical position.

9. The steam dispersion system as claimed in claim 7, including valve means operable between said open and closed loops, by a controller.

10. The steam dispersion system as claimed in claim 8, wherein said steam dispersion tubes include a nozzle having a hole disposed at an angle.

11. A steam dispersion system as claimed in claim 9, wherein said valve means IS operated in a first preheat stage and a second humidification stage.

12. A steam distribution apparatus comprising:

a. a heat exchanger header defining a chamber;

b. a steam distribution apparatus communicating with the heat exchanger chamber;

c. a source of steam at a pressure higher than atmospheric;

d. a heat exchanger having:

i. one end communicating with the source of steam

ii. another end for communicating with the chamber and steam dispersion apparatus

e. valve means for:

i. operating the heat exchanger header in an open-loop for supplying humidification steam to the steam distribution apparatus at atmospheric pressure;

ii. operating the heat exchanger in a closed-loop at the steam pressure higher than atmospheric for heating the heat exchanger chamber wherein condensate within the chamber or steam distribution apparatus can be converted back to humidification steam;

iii. the valve means having a first preheat stage and a second humidification stage.

13. A steam dispersion apparatus as claimed in claim II, wherein the heat exchange header is comprised of either stainless steel, copper, sheet metal, iron, cast iron, or a combination thereof.

14. A steam distribution apparatus as claimed in claim 12, including a plurality of holes for distributing humidification steam.

15. A steam distribution apparatus as claimed in claim 13, wherein the steam distribution apparatus includes insulation disposed about the steam distribution apparatus.

16. A steam distribution apparatus as claimed in claim 14, including a steam control valve for opening the open-looped system.

17. A steam distribution apparatus as claimed in claim 15, wherein the heat exchanger is comprised of either stainless steel, copper, sheet metal, iron, cast iron, or a combination thereof.

18. A steam distribution apparatus as claimed in claim 16, wherein the heat exchanger is disposed in a vertical position and includes a plurality of frustoconical collectors at an acute angle within the steam header.

19. A method of steam humidifying air comprising:

a. supplying a source of steam at a pressure above atmospheric pressure to a heat exchanger disposed within a header defining a chamber wherein the chamber communicates with steam distribution pipes communicating with the air

b. controlling:

i. an isolating valve to supply the steam to one end of the heat exchanger at the pressure above atmospheric to heat the chamber in a closed-loop

ii. a steam control valve to supply steam to the chamber and distribution pipes to supply humidification steam to the air at atmospheric pressure in an open-loop.

20. A method as claimed in claim 18 wherein the distribution pipes are insulated.

21. A method as claimed in claim 19 wherein the pressure of the steam above atmospheric is typically about 15 psi.

22. A steam dispersion system comprising:

a. steam dispersion apparatus;

b. a source of steam at a pressure higher than atmospheric;

c. a heat exchanger communicating with the source of steam and operable in a closed and open loop;

d. an isolating valve to pre-heat the heat exchanger in a closed loop to cause reevaporation of condensate on its external surface;

e. a steam control valve to operate the steam dispersion system in an open-loop so as to provide controlled humidification

23. A nozzle for steam dispersion tubes, the nozzle comprising body extending longitudinally about a generally cylindrical axis; a hole through the body whereby the hole has an axis disposed at an acute angle relative to the cylindrical axis to assist in discharging any condensate by gravity.

24. Insulation for a steam dispersion tube having an outer wall with a plurality of aligned nozzles, said insulation disposed about said outer wall where the cross section of said insulation in the vicinity of the nozzles is less than the cross section of the insulation remote from said nozzles.

25. Insulation as claimed in claim 23 wherein said steam dispersion tube presents a longitudinal axis and said nozzles are longitudinally aligned along said outer wall.