Abstract:
There is disclosed an airflow control terminal for use in controlling the supply of air into a building. The airflow control terminal includes a housing having a bottom, a top, two opposite sides and an interior, said top comprising a grill for allowing air to flow from the interior of the housing to the interior of the building. A heating unit is positioned in the housing between the bottom and top. One of said bottom and opposite sides has a plurality of first apertures to. A damper is mounted to the bottom and opposite sides, the damper configured to control an airflow from outside of the rectangular housing to the interior of the rectangular housing. The heating unit is positioned above the first apertures.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority from U.S. provisional patent application No. 61/390,206 filed on Oct. 6, 2010 the entirety of which is incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The invention relates generally to integrated air flow devices for use with lightly pressurized air streams found in buildings utilizing raised access floor HVAC, ducts or plenums. 
       BACKGROUND OF THE INVENTION 
       [0003]    Many prior art devices and methods have been devised for heating and air conditioning HVAC systems in buildings. Variable air volume (VAV) is well known terminology in the HVAC industry and applies to systems and devices (often called terminals) that change the flow/volume of cool conditioned air to achieve a balance with, the amount of heat gained in the space or building and thereby maintain suitable temperature control of the occupied space. Many such supply air terminals have commercial market application for both ducted systems and in pressurized access floor air plenum HVAC systems. 
         [0004]    Fin tube heating where hot/heating water runs through a copper or steel tube or pipe with perpendicular aluminium fins is one of the most common methods of applying heat at building exterior walls and under windows. Heating coils are the most common method of heating air streams in air ductwork and large building supply fans. There arc also electric coils used in similar air stream manner as well as electric finned heating devices used in electric base board heating. 
         [0005]    Some HVAC systems have been devised for raised access floor systems. Raised access floor systems generally comprise a series of spaced apart pedestals which are supported on the lower end there of on a concrete building structural floor while the upper end there of supports a series of panels defining a raised floor. The space between the said raised floor and the concrete floor defines a cavity or floor plenum. For example, U.S. Pat. No. 4,775,001 relates to the design of air terminal devices used in raised floor air supply plenum systems while the U.S. Pat. No. 6,209,330 relates to an air handler based on chilled water as the cooling force that pushes cool/conditioned air into the raised floor under pressure for cooling computer rooms. 
         [0006]    Under floor air distribution systems using the floor plenum of the raised access floor as a supply air pathway is a proven technology and growing significantly in the North American market place. The most current versions of the raised access floor utilize in floor air terminals which sit on the surface of a floor tile and have the body of the terminal extend into the floor plenum or cavity through a hole in said floor tile or panel. The body of the terminal has openings and a grille for air dispersion. The openings in the terminal are exposed to the floor plenum air. These terminals have various forms or mechanisms for opening and closing the in floor openings. This is typically done both manually by the occupant directly or by electric /electronic actuators controlled by a building control system typical of today&#39;s building technology. 
         [0007]    These raised floor air terminals are generally pressure dependent and deliver predictable range of air flow based on stable floor cavity air pressure whereby the volume of air to the occupied space above the raised floor is a function of the amount and size of openings exposed to the floor pressure and the resistance of the air dispersion grille on the surface of the tile. This in floor plenum pressure is maintained as a constant by in floor pressure sensors providing information to a building control system to control the speed of the fan delivering the air to the plenum all in a manner well known to persons skilled in the art. 
         [0008]    The fan flow generally is adjusted via the control system to maintain a pressure setting between 0.03 inches water gauge to 0.10 inches water gauge. 
         [0009]    The supply air delivered to the air plenums is also typically cooled/conditioned by chilled water cooling coils in said fans, controlled by the building control system and may generally operate at set points from 53° C. to 70° F. with 64° F. being a typical set point. 
         [0010]    Given a floor cavity or plenum with conditioned air at pressure so mentioned the building is cooled by the amount of air, cooler than the occupied space temperature condition, permitted to go through the air terminal into the occupied space. A plurality of terminals is used for rooms and occupied floor in buildings. 
         [0011]    At the exterior walls of a building it is well known to those appropriately trained and skilled that heat is lost from and gained to the building occupied volume. It is for this reason and particularly in raised access floor HVAC buildings, air terminals are located adjacent to the exterior walls and are operated in conjunction with, or have their own integral, heating devices so that these exterior wall (commonly referred to as perimeter walls) air terminals can compensate for both heat gain and heat loss. 
         [0012]    Various in-floor terminals in the North American market place work with separate traditional convective heating fin tube systems typically under the windows. Several current and recent market offerings provide integral fin tube heating and with automatic cooling ability using a well known rotating damper blades on an axis to control the cooling pathways in the terminal. These units also utilize one chamber cooling air flow and a separate chamber for the heating fin tube. 
       SUMMARY OF THE INVENTION 
       [0013]    It is an aspect of this invention to control the flow of air, as typically conditioned for HVAC application, from a lightly pressurized plenum, as typically found in raised floor/under floor air HVAC systems (or also duct plenums) into and through the invention (hereafter called an air flow control terminal or simply air terminal). Said air terminal is typically mounted with top surface level with or on top of said raised floor with the majority of the body of the terminal below the raised floor and surrounded by the pressurized conditioned air in the floor cavity or floor plenum. It is another aspect of this invention that the control of air flow from the lightly pressurized plenum or floor cavity will be done by a sliding damper or air control valve assembly which operates by sliding parallel planes of rigid material (typically sheet metal) each with holes through which air may flow, herein called a plate or blade damper. It is a further aspect of this invention that air permitted to flow from the lightly pressurized conditioned air plenum of the raised floor cavity through the damper will enter the body or single chamber of the air terminal. It is yet another aspect of this invention that this single chamber will contain heating means and it is the integration of the heating means and blade damper in a single chamber of the terminal that allows the terminal to be more space efficient than prior art. It is an additional aspect of this invention that air flowing through the damper, into the chamber, through the heating means will leave the terminal by supply air grille at the top of the terminal which directs air into the occupied space above the raised floor with grille air pattern capability as known and applied by those skilled in the art. 
         [0014]    Therefore, in accordance with one aspect of the invention, there is provided an airflow control terminal for use in controlling the supply of air into a building interior. The airflow control terminal includes a rectangular housing having a bottom, a top, two opposite sides and an interior, said top including a grill for allowing air to flow from the interior of the housing to the interior of the building. A heating unit is positioned in the interior of the rectangular housing above the bottom and below the top. One of said bottom and opposite sides has a plurality of first apertures dimensioned to permit air to flow from outside the housing into the interior of the housing. A damper is slidingly mounted to the said bottom and opposite sides having the first apertures, the damper having a plurality of second apertures dimensioned and positioned on the damper such that the damper can slide between a first position wherein the first and second apertures are aligned to permit an airflow from outside of the rectangular housing to the interior of the rectangular housing and a second position wherein the first and second apertures are misaligned and the airflow is obstructed. The heating unit is positioned above the first and second apertures. 
         [0015]    In accordance with another aspect of the present invention, there is provided an airflow control terminal as described in the preceding paragraph wherein the airflow control terminal is coupled to a lightly pressurized conditioned air passage such that the airflow is from the lightly pressurized conditioned air passage into the interior of the housing. 
         [0016]    In accordance with another aspect of the present invention, there is provided an airflow control terminal as described in the preceding paragraph wherein the airflow through the control terminal has a volume rate which is a function of a degree of alignment between the first and second apertures and wherein the first and second apertures are dimensioned and configured such that there is a linear relationship between the volume rate of airflow and the movement of the damper between its first and second positions. The movement of the damper can be any incremental position in between the first and second position. 
         [0017]    In accordance with another aspect of the present invention, there is provided an airflow control terminal as described in the previous paragraphs wherein the airflow control terminal is able to function in a cooling mode by shutting off the heating means, the amount of cooling in the building interior being controlled by the amount of airflow through the airflow control terminal. 
         [0018]    In accordance with yet another aspect of the present invention, there is provided an airflow control terminal as described in the previous paragraphs wherein the airflow control terminal is able to operate in two heating modes, a first heating mode wherein the damper is positioned close to its second position to minimize the airflow into the interior of the housing to enhance convection through the heating means and a second heating mode wherein the damper is positioned close to its first position to maximize the airflow into the interior of the housing when the lightly pressurized conditioned air passage has an ambient air pressure. 
         [0019]    With the foregoing in view, and other advantages as will become apparent to those skilled in the art to which this invention relates as this specification proceeds, the invention is herein described by reference to the accompanying drawings forming a part hereof, which includes a description of the preferred typical embodiment of the principles of the present invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]      FIG. 1   a  is a top plan view of the air damper/valve portion of the present invention in its fully closed orientation. 
           [0021]      FIG. 1   b  is a cross sectional view through  FIG. 1   a.    
           [0022]      FIG. 2   a  is a top plan view of the air damper/valve portion of the present invention in its fully opened orientation. 
           [0023]      FIG. 2   b  is a cross sectional view through  FIG. 2   a.    
           [0024]      FIG. 3   a  is a plan view of the air damper/valve portion of the present invention in it&#39;s partially opened orientation. 
           [0025]      FIG. 3   b  is a cross sectional view through  FIG. 3   a.    
           [0026]      FIG. 4  is a perspective view of an Airflow and Heating Control Supply Air Terminal made in accordance with the present invention and showing the air damper/valve portion in its fully open orientation. 
           [0027]      FIG. 5  is a cross sectional view of the airflow and heating control supply air terminal of  FIG. 4 . 
           [0028]      FIG. 6  is a schematic representation of a traditional fin tube heating means illustrating normal appurtenances for heating water flow control. 
           [0029]      FIG. 7  is a cross sectional view of an airflow and heating control supply air terminal made in accordance with another aspect of the present invention. 
           [0030]      FIG. 8  is a cross sectional view of an airflow control supply air terminal made in accordance with the present invention used for cooling only applications. 
       
    
    
       [0031]    In the description that follows like parts are marked throughout the specification and the drawings with the same reference numerals. The drawings are not necessarily to scale and in some instances proportions may have been exaggerated in order to more clearly depict certain features of the invention. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0032]    Referring firstly to figures la through  3   b,  the valve portion of the present invention is shown generally as item  10  generally consists of two flat pieces of rigid material, typically sheet metal, and for the purposes of this description called damper plates or blades. These damper plates  1   a  and  1   b  will each have holes  22  and  24 , respectively. The damper plates will typically be oriented with one plate or blade laid with planes of the plates next to each other, one atop the other or potentially side by side. The damper plates are slidingly attached to each other such that one plate may slide relative to the other from a first position, as shown in  FIGS. 2   a  and  2   b  wherein holes  22  and  24  are aligned to permit airflow A to be unobstructed, and a second position, as shown in  FIGS. 1   a  and  1   b  wherein the holes are misaligned and airflow A is obstructed. 
         [0033]    The damper plate holes  22  and  24  will typically be similar or identical size and shape on each damper plate; however, different shapes, sizes and orientations may be used to achieve differences in flow for a given amount of slide of the damper plates relative to each other.  FIGS. 1   a ,  1   b ,  2   a,    2   b,    3   a  and  3   b  illustrate circular boles and respectively show plate&#39;s dampers in plan and section in fully closed, fully open and partially open with a damper stroke the length of the diameter of the circle and the amount of open area as illustrated. Lines with arrows and marked A are shown to depict air flow under the different open and closed conditions of the dampers. Intuitively if the holes were changed to triangles or rectangles of similar size/length as the circle diameter different damper open area would be achieved for the same stroke length (i.e. relative movement of the plates relative to each other) resulting in different flow through the damper. Many shapes and hole geometries may be used to achieve the desired flow outcomes per increment of slide or stroke of the damper. 
         [0034]    The slide damper/air valve may work with each plate sliding but more typically one plate would be a sliding damper and the other would he fixed and be formed into the housing of the air terminal as seen in  FIG. 4  and to house the heating means and air grille means per  FIG. 5 . 
         [0035]    Referring now to  FIG. 4 , and air terminal made in accordance with the present invention is shown generally as item  18 . Air terminal  18  may be any shape; however, a rectangular shape is preferred. Air terminal  18  includes a housing  20  made up of side walls  26  and  28 , bottom portion  30  and top  34  (in this case, top  34  is open). Flanges  36  and  38  may be provided adjacent top  34  to aid in securing the air terminal to a floor duct or the like. Damper plate  32  is slidingly attached to one of walls  26 ,  28  or bottom  30 . In the embodiment illustrated in  FIG. 4 , damper plate  32  is slidingly attached to bottom portion  30 . Damper plate  32  and bottom portion  30  form the valve portion of the air terminal, as described above. Holes  42  are formed on damper plate  32  and corresponding holes  44  are formed on bottom  30 . Damper plate  32  can be slidingly moved through stroke length  38 . The stroke length of the sliding damper blade would typically be for the full diameter or length of the holes ( 42  and  44 ) to maximize flow from the given hole shape and size. The slide direction of the damper blade is parallel to the length of the terminal  18  and illustrated by the directional arrow  38 . The sliding plate of the damper may be done by manual means through linkages or gears or screw drives as would normally be available and configured to allow a button or knob accessible at the grille by the building occupant. More typically this air terminal would move/stroke the blade damper by automatic means through an electric or electronic actuator operated by the building control system all as would be normal and understood by those skilled in the art. 
         [0036]      FIG. 5  illustrates the most typical configuration of the invention as the integration of the heating means  40  in the form of a fin tube heating element (as also depicted in  FIG. 6 ) which is positioned in interior  25  above holes  42  and  44 . The air terminal  18  is also configured to house a air distribution grille  46  formed on top  34  for air dispersion into a building interior  35  above the raised floor defined by floor tile  48  resting on pedestal  50  and concrete structural floor  11 . Normally this form of the invention containing the fin tube heating element  40  (or other heating means) is rectilinear in shape to accommodate the fin tube form of heating means but may be shaped to suit other heating means with damper blade configuration and size also modified to suit the terminal shape. Also normally the rectilinear shape fin tube terminal would be positioned adjacent and parallel to the building exterior wall  9  and window assemblies and below the window  11 . 
         [0037]    In the case of the typical application as seen in  FIG. 5 , the cavity between the raised floor tile  48  the outer building wall  9  and the structural floor  11  forms the under raised floor “floor plenum”  12  well understood by those skilled in the art of designing and constructing raised floor HVAC systems. The raised floor plenum  12  in many applications is lightly pressurized by building fans generally at constant set point within the range of 0.03 inches water gauge to 0.10 under water gauge. This pressurized air reservoir is also typically kept in a cool conditioned reservoir operating between 60° F. and 70° F. 
         [0038]    The normal operating method for this airflow and heating control supply air terminal would be to operate in a cooling mode and a heating mode. These modes would typically be controlled by electric/electronic controls devices normally found in the building HVAC industry and as applied by those skilled in the art. In order to satis 1 ˜′ the room or space temperature as measured by a temperature sensor or thermostat the control system engages heating or cooling as necessary. 
         [0039]    In cooling mode the method is to control the amount of cool pressurized air released from the floor plenum through the terminal and air grille and releasing the conditioned air to the occupied space. In this invention this is done by sliding the damper blade to align the holes to a greater degree when more cooling is required. The building automation system energizes the terminal actuation for the blade damper in a modulating fashion to match cooling air flow with, heat gain in the space through windows or internal gains (people, lights, equipment). In heating mode the heating means, in this example means fin tube  40  (an industry standard device) operates by building heating water circulating through the tube. The tube and fins normally convect heat to the surrounding space. 
         [0040]    With reference to  FIG. 6  the flow of heating water through the fin tube is controlled by a control valve  15  modulated open or closed by an electric/electronic actuator common to the HVAC system. Other heating means such as a heating coil would operate in a similar way and electronic heating means the amount of electric current would be controlled to affect heat output. In heating mode when the building floor plenum  12  is operating under normal temperature and pressure conditions the control system will move the plate damper  1   a  to a more closed position, called, the “minimum” air flow condition to limit the flow of conditioned air that is to be heated in order to address HVAC industry energy codes governing heating conditioned air. When the plate damper  1  is moved to and holds this minimum open position in heating mode (perhaps in the range of 20% of total flow by way of example) the fin tube control valve  15  modulates in a range between open and closed to obtain heat output for controlled heating of the space. The modulation of the valve for control of heat output for controlled heating of the space. The modulation of the valve for controlled heat output is a normal industry control algorithm and operating system. In this invention with the integrated healing and cooling single chamber terminal provides an increased amount of air flow through the fin beyond industry normal, convection which enhances heat exchange and heat output of the fin tube assembly. This is also a phenomena that has been demonstrated by prior art as fan assisted fin tube assemblies are available to the HVAC market with higher heat output than free standing fin tube. The characteristic of enhanced heat transfer also invites the prospect of using lower heating water to enhance the operating efficiency of well known condensing boiler systems or potential water to water heat pump concepts understood by those skilled in the art. 
         [0041]    Another mode for heating is also available when building air conditioning systems that normally provide the conditioned pressurized air supply to the plenum  12  are shut off in night mode or weekend mode. 
         [0042]    Under this condition the sliding plate damper  1  moves to the 100% open position (holes frilly aligned) and the fin tube heating operates in pure convection mode (without pressurized airflow assistance) with a convection air stream and path from the floor plenum  12  through the holes  42  and  44  (see  FIG. 5 ) through the heated fin tube  40  and the grille  46  to the occupied space. 
         [0043]    It is also possible to create a cooling only terminal based on this rectilinear configuration which may be applied where heating is provided by other methods at other locations or not required due to climate or placement of terminal where there are no heat losses but only heat gains. In  FIG. 8  such a concept is illustrated. A baffle plate  19  of small holes configured to equalize pressure and air flow to the air grille  13  may be used. There is much prior art related to cooling only terminals. 
         [0044]    It is further possible to configure the damper to shape differently and use multiple surfaces of the terminal. In  FIG. 7  the damper  52  has holes  54  in two planes of the alternative damper blade shape. Air flow in this case can enter the terminal through holes  56  on side walls  58  and  60 ; thereby permitting a larger surface with holes through which air can flow. This would result in potentially greater air flow. A generic heating means  62  is also shown. 
         [0045]    A specific embodiment of the present invention has been disclosed; however, several variations of the disclosed embodiment could be envisioned as within the scope of this invention. It is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the scope of the following claims.