Methods and systems for integrating sound attenuation into a filter bank

A filter bank is provided. The filter bank includes a housing having a front face and a back face. Air flows along an air flow path from the front face to the back face. A filter layer is held in the housing. The filter layer is oriented between the front and back faces such that air flows through the filter layer before discharging from the back face. An attenuation layer is positioned within the housing to attenuate sound as the sound propagates between the front and back faces. The attenuation layer is oriented to extend along the air flow direction.

BACKGROUND OF THE INVENTION

Embodiments relate to air handling units and, more particularly, to methods and systems for air filtering and sound attenuating in an air handling unit.

Air-handling systems (also referred to as an “air handler”) have traditionally been used to condition buildings or rooms (hereinafter referred to as “structures”). The air-handling system may contain components such as cooling coils, heating coils, filters, humidifiers, fans, sound attenuators, controls, and other devices functioning to at least meet a specified air capacity which may represent all or only a portion of a total air handling requirement of the structure. The air-handling system may be manufactured in a factory and brought to the structure to be installed or it may be built on site using the appropriate devices to meet the specified air capacity. The air-handling compartment of the air-handling system includes one or more fan inlet cones, fan units and a discharge plenum. The fan units include an inlet cone, a fan, a motor, fan frame, and any appurtenance associated with the function of the fan (e.g. dampers, controls, settling means, and associated cabinetry).

In certain applications, filter banks and sound attenuator banks are positioned upstream from the fan. The filter bank is generally spaced apart from the sound attenuator so that maintenance can be performed from within the air handler. The space between the filter bank and sound attenuator increases the size of the air handler and may cause an unwanted pressure drop therein.

There remains a need for a more compact filter bank and sound attenuator configuration that reduces the pressure drop within the air handler.

SUMMARY OF THE INVENTION

In one embodiment, a filter bank is provided. The filter bank includes a housing having a front face and a back face. Air flows along an air flow path from the front face to the back face. A filter layer is held in the housing. The filter layer is oriented between the front and back faces such that air flows through the filter layer before discharging from the back face. An attenuation layer is positioned within the housing to attenuate sound as the sound propagates between the front and back faces. The attenuation layer is oriented to extend along the air flow direction.

In another embodiment, an air handling unit is provided. The air handling unit includes a fan for drawing an air flow path through the air handling unit. A filter bank is provided for filtering the air flow path. The filter bank includes a housing having a front face and a back face. Air flows along the air flow path from the front face to the back face. A filter layer is held in the housing. The filter layer is oriented between the front and back faces such that air flows through the filter layer before discharging from the back face. An attenuation layer is positioned within the housing to attenuate sound as the sound propagates between the front and back faces. The attenuation layer is oriented to extend along the air flow direction.

In a further embodiment, a method of filtering and attenuating sound within an air handling unit is provided. The method includes positioning a housing having a front face and a back face within the air handling unit. Air flows along an air flow path from the front face to the back face. A filter layer is coupled within the housing. The filter layer is oriented between the front and back faces such that air flows through the filter layer before discharging from the back face. An attenuation layer is positioned within the housing to attenuate sound as the sound propagates between the front and back faces. The attenuation layer is oriented to extend along the air flow direction.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1illustrates an air handling unit100. The air handling unit100includes an air processing system200having an inlet102and an outlet104. The air handling unit100is configured to condition air flowing through a room106. The room106includes an inlet plenum108and an outlet plenum110. The inlet plenum108extends between the room106and the outlet104of the air handling unit100. The outlet plenum110extends from the room106to the inlet102of the air handling unit100. Vents112are positioned at the junction of the inlet plenum108and the room106. A return vent114is positioned at the junction of the outlet plenum110and the room106. Optionally, filters may be positioned at each junction. The inlet plenum108and the outlet plenum110may include dampers and/or filter banks positioned therein.

During operation, air flows from the air handling unit100through the inlet plenum108. The air is discharged from the vent112into the room106and circulates there through. During circulation throughout the room106, at least some of the air is channeled through the return vent114. The air flows through the outlet plenum110and returns to the air handling unit100through inlet102. The air is reconditioned in the air handling unit100and recirculated to the room106through inlet plenum108.

FIG. 2illustrates an air processing system200that utilizes a fan array air handling system in accordance with an embodiment. The system200includes an inlet202that receives air. A heating section206that heats the air is included and followed by an air handling section208. A humidifier section210is located downstream of the air handling section208. The humidifier section210adds and/or removes moisture from the air. Cooling coil sections212and214are located downstream of the humidifier section210to cool the air. A filter section216is located downstream of the cooling coil section214to filter the air. The sections may be reordered or removed. Additional sections may be included.

The air handling section208includes an inlet plenum218and a discharge plenum220that are separated from one another by a bulkhead wall225which forms part of a frame224. Fan inlet cones222are located proximate to the bulkhead225of the frame224of the air handling section208. The fan inlet cones222may be mounted to the bulkhead wall225. Alternatively, the frame224may support the fan inlet cones222in a suspended location proximate to, or separated from, the bulkhead wall225. Fans226are mounted to drive shafts on individual corresponding motors228. The motors are mounted on mounting blocks to the frame224. Each fan226and the corresponding motor228form one of the individual fan units232that may be held in separate chambers230. The chambers230are shown vertically stacked upon one another in a column. Optionally, more or fewer chambers230may be provided in each column. One or more columns of chambers230may be provided adjacent one another in a single air handling section208.

FIG. 3illustrates a top view of the air handling section208shown inFIG. 1. The air handling section208includes an upstream end234and a downstream end236. Fans226are positioned between the inlet plenum218and the discharge plenum220. The inlet plenum218is upstream of the fans226. The discharge plenum220is downstream of the fans226. A filter bank238is positioned at the upstream end234of the air handling section208. The filter bank238includes a plurality of filters240positioned adjacent one another in a row. The filters240extend within a filter bank housing241. The filters are positioned to form an air tight interface between each filter240. The filters240may be formed from foam, pleated paper, spun fiberglass, and/or any other suitable filtering medium. The filters240are configured to remove impurities from the air flowing through the air handling section208.

A plurality of sound attenuation panels242are positioned downstream from the filters240. The sound attenuation panels242are positioned in a row with channels244extending therebetween. The sound attenuation panels242may have a shape that exhibits a low pressure drop thereacross. Additionally, the sound attenuation panels242may be perforated or solid. Additional details regarding the sound attenuation panels242are described in more detail below with respect toFIGS. 28-34. In the exemplary embodiment, the sound attenuation panels242are arranged parallel to the filters240. Optionally, and as described with respect toFIGS. 4-25, the filters240and sound attenuation panels242may be arranged in non-linear and/or non-parallel configurations.

FIGS. 4-25illustrate various embodiments of filter banks238that may be used with the air handling section208or in another application. It should be appreciated that the filter banks238of the various embodiments may also be utilized with a ceiling unit or any other suitable heating, cooling, or ventilation system. The filter banks238may be positioned upstream or downstream from the fans226. The filter banks include at least one filtering layer and at least one attenuating layer positioned proximate or immediately adjacent to the filtering layer. The filter banks238occupy a small space within the air handling section208and exhibit a low pressure drop thereacross. It should be noted that the filter banks238are illustrated in the air handling section208. Optionally, the filter banks238may be positioned in the inlet plenum108and/or the outlet plenum110of the air handling unit100.

FIG. 4is a perspective view of a filter/sound attenuation bank housing301having outer walls303. The filter/sound attenuation bank housing301contains a filter/sound attenuation bank300. Air flows in the direction314through the filter/sound attenuation bank300. A coupling frame305extends along the outer walls303. The filter/sound attenuation bank300is coupled to the housing301. Optionally, the filter/sound attenuation bank300is coupled to the coupling frame305. The filter/sound attenuation bank300includes a plurality of filtering layers302and a plurality of attenuating layers304. The filtering layers302and the attenuating layers304may be coupled to the coupling frame305and/or the housing301. The filtering layers302extend between adjacent attenuating layers304. The filter/sound attenuation bank300includes a top end306and a bottom end308. In the exemplary embodiment, the top end306and the bottom end308include a filtering layer302that extends between an attenuating layer304and the housing301. Optionally, an attenuating layer304may be coupled directly to the housing301. The filter/sound attenuation bank300is coupled to the housing301and/or coupling frame305to form an air tight interface. The filtering layers302and the attenuating layers304are coupled together to form an air tight interface. Airflow is directed through the filtering layers302of the filter/sound attenuation bank300. Optionally, the attenuating layers304may represent interior walls that are semi-permeable and allow airflow therethrough.

FIG. 5is a side view of an embodiment of the filter/sound attenuation bank300. The housing301includes planar front and back faces310and312. The front and back faces310and312are perforated to allow air to flow therethrough in the direction of arrows314. The attenuation layers304are spaced apart from the outer walls303. The attenuation layers304are oriented to extend between the front and back faces310and312. Optionally, the attenuation layers304may only extend partially from or to either or both of the front and back faces310and312. The filtering layers302and the attenuating layers304are stacked in an interlaced manner transverse to the direction of air flow314. The attenuating layers304may be arranged parallel to each other and substantially parallel to the direction of air flow314. Optionally, the attenuating layers304may be positioned at a common or different acute angles to one another and an acute angle to the air flow314.

Each attenuating layer304includes opposed ends316, planar site faces318and a middle portion320extending therebetween. The ends316of each attenuating layer304may be rounded or convex. Optionally, the ends316of the attenuating layers304may be flat, pointed, concave, and/or non-uniformly rounded. Air channels322are formed by adjacent attenuating layers toward the front and back faces310and312. The filter layer302is oriented to traverse for air flow through the filter/sound attenuation bank300. The air channels322are also located between the attenuation layers304and outer walls303of the housing301. The attenuation layers304may represent interior walls that are semi-permeable and form an inner air channel324and outer air channels322. Air flows through the air channels322,324in the direction of314. The air channels322and324have widths326,328and330, that may be equal to one another or differ in width. The air channels322,324have a common length332between parallel planar front and back faces310and312. Optionally, the front and/or back faces310and312may be contoured to be non-planar such that the length332may be different within an individual channel322,324or between different channels322,324.

Each filter layer302extends toward the front and back faces310and312. The filter layer302is oriented to traverse diagonally from an end316of a first attenuating layer304to an end316of an adjacent attenuating layer304. Optionally, the ends334of the filter layers302may extend to or from middle portions320of the attenuating layers304. The ends334may engage and adjoin an end316of a first attenuating layer304and a middle portion320of an adjacent attenuating layer304. The ends334of the filter layers302abut and form an air tight interface with the ends316or middle portions320of the attenuating layers304.

FIG. 6is a side view of a filter/sound attenuation bank1000. The attenuation layers1004extend at least partially from or to either or both of the front and back faces1010and1012. The filtering layers1002and the attenuating layers1004are stacked in an interlaced manner transverse to the direction of air flow1014. The attenuating layers1004may be arranged in parallel or at a common or different angle to one another.

Each attenuating layer1004includes opposed ends1016, planar site faces1018and a middle portion1020extending therebetween. The ends1016of each attenuating layer1004may be rounded, flat, pointed, convex, concave, and/or non-uniformly rounded. The middle portion1020has a width1030that is greater than a width1032of the ends1016. Air channels1022are formed by adjacent attenuating layers between the front and back faces1010and1012. The air channels1022are also located between the attenuation layers1004and outer walls1003of the housing1001. Optionally, the attenuation layers1004may represent interior walls that are semi-permeable and form an inner air channel1024and outer air channels1022.

Each filter layer1002extends toward the front and back faces1010and1012. The filter layer1002is oriented to traverse diagonally from an end1016of a first attenuating layer1004to an end1016of an adjacent attenuating layer1004. Optionally, the ends1034of the filter layers1002may extend to or from middle portions1020of the attenuating layers1004. The ends1034engage a coupling mechanism1035that couples the filtering layers1002to the attenuating layers1004. The coupling mechanism1035includes outer clamps1037and an inner clamp1039. The ends1034of the filtering layers1002engage one of the outer clamps1037to form an airtight interface. The ends1016of the attenuating layer1004engage the inner clamp1039to form an airtight interface. Optionally, the coupling mechanism1035may adjoin an end1016of a first attenuating layer1004and a middle portion1020of an adjacent attenuating layer1004to form an airtight interface.

FIG. 7is a perspective view of a filter/sound attenuation bank housing351having outer walls353, a top wall356, and a bottom wall358. The filter/sound attenuation bank housing351contains a filter/sound attenuation bank350. Air flows in the direction357through the filter/sound attenuation bank350. A coupling frame355extends along the outer walls353. The filter/sound attenuation bank350is coupled to the housing351. Optionally, the filter/sound attenuation bank350is coupled to the coupling frame355. The filter/sound attenuation bank350includes a plurality of filtering layers352and a plurality of attenuating layers354. The filtering layers352extend between the top wall356and the bottom wall358. The filtering layers352couple to the walls356,358to form an airtight interface. Optionally, the filtering layers352couple to the coupling frame355. The filtering layers352are arranged in a row along the same plane. Optionally, the filtering layers352are arranged in a non-planar row.

The attenuating layers354extend between adjacent filtering layers352. The attenuating layers354may be coupled to the coupling frame355and/or the housing351to form an airtight interface. Optionally, the attenuating layers354may be coupled to the filtering layers352to form an airtight interface. The attenuating layers354extend substantially perpendicularly to the filtering layers352. Optionally, the attenuating layers354may be arranged at a common or different angle from the filtering layers352. Airflow is directed through the filtering layers352of the filter/sound attenuation bank350. Optionally, the attenuating layers354may represent interior walls that are semi-permeable and allow airflow therethrough.

FIG. 8illustrates a top view of the filter/sound attenuation bank350. The filtering layers are352are arranged in the same plane. Optionally, the filtering layers352are arranged at angles with respect to one another. Additionally, the filtering layers352may be arranged in a concave, convex, and/or curved configuration. The filtering layers352are arranged so that the ends362are positioned adjacent and/or abut one another at the junction366. Filter/sound attenuation bank350includes at least one row of filtering layers352arranged in parallel and/or at angles to one another.

The attenuating layers354are positioned parallel to one another. Optionally, the attenuating layers354may be positioned at angles to one another. The attenuating layers354extend substantially perpendicular and/or at an angle with respect to the filtering layers352. Each attenuating layer354abuts the junction366of the filter layer ends362and/or the planar face364of a filter layer352. The middle portion372of each attenuating layer354extends in a plane between the ends370so that the attenuating layer354has a uniform width385. The ends370may be rounded, flat, pointed, convex, concave, and/or non-uniformly rounded. Airflow is directed through the filtering layers352and around the attenuating layers354. Optionally, the attenuating layers354may represent interior walls that are semi-permeable and allow airflow therethrough.

FIG. 9illustrates a top view of a filter/sound attenuation bank1150. Air flows in a direction1157through the filter/sound attenuation bank1150. Each filtering layer1152has a pair of ends1162and planar faces1164extending therebetween. The filtering layers are1152are arranged in the same plane. Optionally, the filtering layers1152are arranged at angles with respect to one another. Additionally, the filtering layers1152may be arranged in a concave, convex, and/or curved configuration. The filtering layers1152are arranged so that the ends1162are positioned adjacent one another. Optionally, the filtering layers1152are arranged so that the ends1162abut each other at a junction1166to form an airtight interface.FIG. 9illustrates a single row of filtering layers1152. Optionally, filter/sound attenuation bank1150may include multiple rows of filtering layers1152arranged in parallel and/or at angles to one another.

The attenuating layers1154are positioned parallel to one another. Optionally, the attenuating layers1154may be positioned at angles to one another. The attenuating layers1154extend substantially perpendicular to the filtering layers1152. Optionally, the attenuating layers1154may extend at angles with respect to the filtering layers1152. Each attenuating layer1154abuts a junction1166of the filter layer ends1162to form an airtight interface. Optionally, the attenuating layers1154may abut the planar face1164of a filter layer1152. The attenuating layers1154may also be coupled to the junction1166and/or planar face1164utilizing a coupling device.

Each attenuating layer1154includes a pair of ends1170and a middle portion1172extending therebetween. In the exemplary embodiment, the middle portion1172has a width1181that is greater than the width1183of the ends1170. The ends1170may be rounded, flat, pointed, convex, concave, and/or non-uniformly rounded. Airflow is directed through the filtering layers1152and around the attenuating layers1154. Optionally, the attenuating layers1154may represent interior walls that are semi-permeable and allow airflow therethrough.

FIG. 10illustrates a top view of a filter/sound attenuation bank1250. The filtering layers are1252are arranged in the same plane. Optionally, the filtering layers1252are arranged at angles with respect to one another. Additionally, the filtering layers1252may be arranged in a concave, convex, and/or curved configuration. The filtering layers1252are arranged so that the ends1262are positioned adjacent and/or abut one another at the junction1266. Filter/sound attenuation bank1250includes at least one row of filtering layers1252arranged in parallel and/or at angles to one another.

The attenuating layers1254extend at an angle from the filtering layers1252. Each attenuating layer1254includes a first attenuating member1274and a second attenuating member1276. The first attenuating member1274abuts the junction1266of the filter layer ends1262and/or the planar face1264of a filter layer1252. The second attenuating member1276extends at an angle from the second attenuating member1276. The attenuating members1274,1276are angled so as to eliminate a line of sight between adjacent attenuating layers1254. The angle between the attenuating members1274,1276may be the same for each attenuating layer1254. Optionally, the angle of each attenuating layer1254may vary. Optionally, the filter/sound attenuation bank1250may include at least one attenuating layer1254that extends perpendicular to the filtering layers1252. The attenuating layers1254may have a uniform width and/or widths that vary along the length of the middle portion1272. The ends1270may be rounded, flat, pointed, convex, concave, and/or non-uniformly rounded. Airflow is directed through the filtering layers1252and around the attenuating layers1254. Optionally, the attenuating layers1254may represent interior walls that are semi-permeable and allow airflow therethrough.

FIG. 11is a top view of a filter/sound attenuation bank1350. The attenuating member1354has a third attenuating member1378extending at angle from the second attenuating member1376. The attenuating members1374,1376, and1378are angled so as to eliminate a line of sight between the attenuating layers1354. Airflow1357is directed through the filtering layers1352and around the attenuating layers1354. Optionally, the attenuating layers1354may represent interior walls that are semi-permeable and allow airflow therethrough.

FIG. 12is a top view of a filter/sound attenuation bank1450. The attenuation layers1454include attenuating members1474,1476, and1478. The attenuating members1474,1476, and1478are angled to eliminate a line of sight therebetween. The attenuating members1454may include ends1470that are rounded, flat, pointed, convex, concave, and/or non-uniformly rounded. The filtering layers1452extend between adjacent attenuating layers1454. The filtering layers1452may extend at an angle between the attenuating layers1454. Optionally, the filtering layers1452extend perpendicular to each attenuating layer1454. The attenuating layers1454and the filtering layers1452are coupled together to form an airtight interface.FIG. 12illustrates a single filtering layer1452extending between each adjacent attenuating layer1454. Optionally, multiple filtering layers1452may extend between each attenuating layer1454. Airflow is directed through the filtering layers1452and around the attenuating layers1454. Optionally, the attenuating layers1454may represent interior walls that are semi-permeable and allow airflow therethrough.

In another embodiment, a filter bank may have any combination of the filtering layers and attenuating layers shown inFIGS. 8-12.

FIG. 13is a perspective view of a filter/sound attenuation bank housing401having outer walls403and planar front and back faces410and412. The front and back faces410and412are perforated to allow air to flow therethrough in the direction of arrows414. The filter/sound attenuation bank housing401contains a filter/sound attenuation bank400. Air flows in the direction414through the filter/sound attenuation bank400. A coupling frame405extends along the outer walls403. The filter/sound attenuation bank400is coupled to the housing401. Optionally, the filter/sound attenuation bank400is coupled to the coupling frame405. The filter/sound attenuation bank400includes a plurality of filtering layers402and a plurality of attenuating layers304. The filtering layers402and the attenuating layers404may be coupled to the coupling frame405and/or the housing401.

The attenuating layers404include a front plurality of attenuating layers407and a back plurality of attenuating layers409. Each attenuating layer404includes a front end415, a back end414, and a middle416extending between the ends415,414. The front plurality of attenuating layers407extend along the front face410. The front plurality of attenuating layers407are positioned substantially parallel to one another. Optionally, the front plurality of attenuating layers407are angled with respect to one another. The front plurality of attenuating layers407extend from the front face410to approximately a center411of the filter bank housing401. Optionally, the front plurality of attenuating layers407extend short of or beyond the center411. The back plurality of attenuating layers409extend along the back face412. The back plurality of attenuating layers409are positioned substantially parallel to one another. Optionally, the back plurality of attenuating layers409are angled with respect to one another. The back plurality of attenuating layers409extend from the back face412to approximately the center411of the filter bank housing401. Optionally, the back plurality of attenuating layers409extend short of or beyond the center411.

The filtering layers402extend between the front plurality of attenuating layers407and the back plurality of attenuating layers409. Each filtering layer402extends from a front end415of a back attenuating layer409and a back end414of a front attenuating layer407. The filter/sound attenuation bank400includes a top end406and a bottom end408. In the exemplary embodiment, the top end406and the bottom end408include a filtering layer402that extends between an attenuating layer404and the housing401. Optionally, an attenuating layer404may be coupled directly to the housing401. The filter/sound attenuation bank400is coupled to the housing401and/or coupling frame405to form an air tight interface. The filtering layers402and the attenuating layers404are coupled together to form an air tight interface. Airflow is directed through the filtering layers402of the filter/sound attenuation bank400. Optionally, the attenuating layers404may represent interior walls that are semi-permeable and allow airflow therethrough.

FIG. 14is a side view of an embodiment of the filter/sound attenuation bank400. The attenuation layers404extend between the outer walls403. The attenuation layers404are oriented to extend from one of the front face410and the back face412. The front plurality of attenuating layers407extend at least partially from the front face410to the back face412. The back plurality of attenuating layers409extend at least partially from the back face412to the front face410. The filtering layers402and the attenuating layers404are stacked in an interlaced manner transverse to the direction of air flow417. The attenuating layers404may be arranged parallel to each other and substantially parallel to the direction of air flow417. Optionally, the attenuating layers404may be positioned at a common or different acute angles to one another and an acute angle to the air flow417.

The attenuating layer ends415,414may be rounded, flat, pointed, concave, convex, and/or non-uniformly rounded. Air channels422are formed by adjacent attenuating layers toward the front and back faces410and412. The filtering layer402is oriented traverse to air flow through the filter/sound attenuation bank400. The air channels422are also located between the attenuation layers404and outer walls403of the housing401. The attenuation layers404may represent interior walls that are semi-permeable and form an inner air channel424and outer air channels422. Air flows through the air channels422,424in the direction of417. The air channels422and424have widths426,428and430, that may be equal to one another or differ in width. The air channels422,424have a common length432between parallel planar front and back faces410and412. Optionally, the front and/or back faces410and412may be contoured to be non-planar such that the length432may be different within an individual channel422,424or between different channels422,424.

The filtering layers402extend between the front plurality of attenuating layers407and the back plurality of attenuating layers409. Each filtering layer402extends from a front end415of a back attenuating layer409and a back end414of a front attenuating layer407. Optionally, the ends434of the filter layers402may extend to or from middle portions420of the attenuating layers404. The ends434may engage and adjoin an end415,414of an attenuating layer404and a middle portion420of an adjacent attenuating layer404. The ends434of the filter layers402abut and form an air tight interface with the ends416or middle portions420of the attenuating layers404.

FIG. 15is a side view of a filter/sound attenuation bank1400. The front plurality of attenuating layers1407extend at least partially from the front face1410to the back face1412. The back plurality of attenuating layers1409extend at least partially from the back face1412to the front face1410. The filtering layers1402and the attenuating layers1404are stacked in an interlaced manner. An additional plurality of attenuating layers1405are arranged between adjacent front attenuating layers1407and between adjacent back attenuating layers1409. The attenuating layers1404and1405may be arranged parallel to each other and substantially parallel to the direction of air flow1417. Optionally, the attenuating layers1404and1405may be positioned at a common or different acute angles to one another and an acute angle to the air flow1417. Air channels1422are formed by adjacent attenuating layers. The attenuation layers1404and1405may represent interior walls that are semi-permeable and form an inner air channel1424and outer air channels1422. Air flows through the air channels1422,1424in the direction of1417. The filtering layers1402extend between the front plurality of attenuating layers1407and the back plurality of attenuating layers1409.

FIG. 16illustrates a filter/sound attenuation bank housing451having a filter/sound attenuation bank450. The housing451includes outer walls453, a top455, a bottom457, a front face459, and a back face461. The front face459and at least a portion of the back face461are perforated to allow air to flow therethrough in the direction of arrows456. Optionally, a coupling frame405extends along the outer walls453and the top455. The filter/sound attenuation bank450includes attenuating layers454and filtering layers452. The attenuating layers454and filtering layers452are coupled to the housing451and/or the coupling frame405to form an airtight interface.

Attenuating layers454extend between the front face459and the back face461. The attenuating layers454are arranged perpendicular to each of the front face459and the back face461. Optionally, the attenuating layers454may extend at an acute angle with respect to the front and back faces459,461. The attenuating layers454are positioned in parallel. Optionally, the attenuating layers454may be acutely angled with respect to each other. Airflow is directed around attenuating layers454and through the filtering layers452of the filter/sound attenuation bank450. Optionally, the attenuating layers454may represent interior walls that are semi-permeable and allow airflow therethrough.

Filtering layers452extend at least partially from the back face461. The filtering layers452extend substantially perpendicular to the front and back faces459,461. Optionally, the filtering layers452may extend at an acute angle to front and back faces459,461. The filtering layers452are arranged parallel to one another. Optionally, the filtering layers452may be arranged at an angle to one another. A pair of filtering layers452is positioned within a pair of adjacent attenuating layers454. Optionally, any number of filtering layers452may be positioned between adjacent attenuating layers454. The filtering layers452form an inner channel462through a perforated portion464of the back face461.

FIG. 17illustrates a top view of the filter/sound attenuation bank450. Adjacent attenuating layers454form an outer channel466. The outer channel466has a width468. In the exemplary embodiment, the attenuating layers454form a plurality of outer channels466each having the same width468. Optionally, channels466may have varying widths468. The outer channel466has a uniform width468. Optionally, the width468of the outer channel466may vary. The attenuating layers454are arranged perpendicular to each of the front face459and the back face461. Optionally, the attenuating layers454may extend at an acute angle with respect to the front and back faces459,461. The attenuating layers454are positioned in parallel. Optionally, the attenuating layers454may be acutely angled with respect to each other.

A pair of filtering layers452extends from the back face461. The filtering layers452extend substantially perpendicular to the front and back faces459,461. Optionally, the filtering layers452may extend at an acute angle to front and back faces459,461. The filtering layers452may be arranged at any angle with respect to one another. The filtering layers452extend between a pair of adjacent attenuating layers454. The filtering layers452form an inner channel462to a perforated portion464of the back face461. An attenuating cap470extends between the ends472of adjacent filtering layers452. The attenuating cap470may represent interior wall or a semi-permeable membrane allowing air flow into the inner channel462. The attenuating cap may be rounded, flat, pointed, concave, convex, and/or non-uniformly rounded.

FIG. 18illustrates a filter/sound attenuation bank housing501having a filter/sound attenuation bank500. The housing501includes outer walls503, a top505, a bottom507, a front face509, and a back face511. The front face509and at least a portion of the back face511are perforated to allow air to flow therethrough in the direction of arrows504. Optionally, a coupling frame513extends along the outer walls503and the top505. The filter/sound attenuation bank500includes attenuating layers504and filtering layers502. The attenuating layers504and filtering layers502are coupled to the housing501and/or the coupling frame513to form an airtight interface.

Attenuating layers504extend at least partially between the front face509and the back face511. In the exemplary embodiment, the attenuating layers504extend from the back face511. Optionally, the attenuating layers504may extend from the front face509. The attenuating layers504are arranged perpendicular to each of the front face509and the back face511. Optionally, the attenuating layers504may extend at an acute angle with respect to the front and back faces509,511. The attenuating layers504are positioned in parallel. Optionally, the attenuating layers504may be acutely angled with respect to each other. Airflow is directed through the filtering layers502and through a channel506extending through the attenuating layers504. Optionally, the attenuating layers504may represent interior walls that are semi-permeable and allow airflow therethrough. Optionally, the airflow is directed through the channel506to the filtering layers502.

Filtering layers502extend at least partially from the front face509. Optionally, the filtering layers extend at least partially from the back face511. The filtering layers502extend substantially perpendicular to the front and back faces509,511. Optionally, the filtering layers502may extend at an acute angle to front and back faces509,511. The filtering layers502are arranged parallel to one another. Optionally, the filtering layers502may be arranged at an angle to one another. Each filtering layer502abuts an attenuating layer504to form an airtight interface. The filtering layers502direct airflow into the channel506.

FIG. 19illustrates a top view of the filter/sound attenuation bank500. The filtering layers502abut the attenuating layers504to form the channel506. The attenuating layers504and the filtering layers502are arranged perpendicular to each of the front face509and the back face511. Optionally, the attenuating layers504and filtering layers502may extend at an acute angle with respect to the front and back faces509,511. The attenuating layers504and the filtering layers502are positioned in parallel. Optionally, the attenuating layers504and the filtering layers502may be acutely angled with respect to each other.

In the exemplary embodiment, the attenuating layers504have a front end510and a back end512. The front end510has a width514that is greater than a width516of the back end512. The channel506expands from the front face509to the back face511. Optionally, the attenuating layers504may have a uniform width. Optionally, the attenuating layers may be rounded, flat, pointed, concave, convex, and/or non-uniformly rounded. The attenuating layers504and the filtering layers502form the channel506. The channel506directs airflow to a perforated portion517of the back face511.

FIG. 20illustrates a filter/sound attenuation bank housing551having a filter/sound attenuation bank550. The housing551includes outer walls553, a top555, a bottom557, a front face559, and a back face561. The front face559and at least a portion of the back face561are perforated to allow air to flow therethrough in the direction of arrows558. Optionally, a coupling frame563extends along the outer walls553and the top555. The filter/sound attenuation bank550includes attenuating layers554and filtering layers552. The attenuating layers554and filtering layers552are coupled to the housing551. Optionally, the attenuating layers554and the filtering layers552may be coupled to coupling frame563to form an airtight interface.

Filtering layers552extend at least partially between the front face559and the back face561. The filtering layers552are arranged perpendicular to each of the front face559and the back face561. Optionally, the filtering layers552may extend at an acute angle with respect to the front and back faces559,561. The filtering layers552are positioned in parallel. Optionally, the filtering layers552may be acutely angled with respect to each other. Airflow is directed through a channel556formed between the filtering layers552and through each filtering layer552.

Attenuating layer554extends at least partially from the back face561. Optionally, the attenuating layer554extends at least partially from the front face559. The attenuating layer554extends substantially perpendicular to the front and back faces559,561. Optionally, the attenuating layer554may extend at an acute angle to front and back faces559,561. The attenuating layer554is arranged parallel to the filtering layers552. Optionally, the attenuating layer554may be arranged at an angle with respect to the filtering layer552. The attenuating layer554directs airflow through each of the filtering layers552. Optionally, the attenuating layers554may represent interior walls that are semi-permeable and allow airflow therethrough.

FIG. 21illustrates a top view of the filter/sound attenuation bank550. The filtering layers552form the channel556. The attenuating layer554and the filtering layers552are arranged perpendicular to each of the front face559and the back face561. Optionally, the attenuating layer554and filtering layers552may extend at an acute angle with respect to the front and back faces559,561. The attenuating layer554and the filtering layers552are positioned in parallel. Optionally, the attenuating layer554and the filtering layers552may be acutely angled with respect to each other.

In the exemplary embodiment, the attenuating layer554has a front end560and a back end562. The back end562is coupled to the back face561to form an airtight interface. The front end560is rounded. Optionally, the front end560may be flat, pointed, concave, convex, and/or non-uniformly rounded. The filtering layers552form the channel556. The channel556directs airflow to an opening564of the back face561. Optionally, opening564may be a perforated portion of the back face561.

FIG. 22illustrates a filter/sound attenuation bank housing601having a filter/sound attenuation bank600. The housing601includes outer walls603, a top605, a bottom607, a front face609, and a back face611. The front face609and at least a portion of the back face611are perforated to allow air to flow therethrough in the direction of arrows606. Optionally, a coupling frame613extends along the outer walls603and the top605. The filter/sound attenuation bank600includes attenuating layers604and filtering layers602. The attenuating layers604and filtering layers602are coupled to the housing601. Optionally, the attenuating layers604and the filtering layers602may be coupled to coupling frame613to form an airtight interface.

FIG. 23illustrates a perspective view of the filter/sound attenuation bank600. The filter/sound attenuation bank600includes a plurality of filtering layers602and a plurality of attenuating layers604. The plurality of filtering layers602includes a plurality of upstream filtering layers608, a plurality of first downstream filtering layers610, and a plurality of second downstream filtering layers612. Each filtering layer602includes an upstream end614and a downstream end616. In the exemplary embodiment, the ends614and616are flat. Optionally, the ends614and616may be rounded, concave, convex, pointed, and/or non-uniformly rounded.

The downstream end616of upstream filtering layer608is positioned adjacent the upstream end614of each of the first and second downstream filtering layers610and612. Optionally, these ends may be coupled and/or formed integrally to form an airtight interface. The first downstream filtering layer610extends from the upstream filtering layer608at an acute angle. The second downstream filtering layer612extends from the upstream filter layer608at an acute angle that is equal and opposite to the angle between the first downstream filtering layer612and the upstream filtering layer608. Optionally, the two angles are not equal.

The attenuating layers604extend between the upstream filtering layer608and one of the first downstream filtering layer610and the second downstream filtering layer612. Optionally, the attenuating layers604may extend between the first and second downstream attenuating layers610and612. The attenuating layers604extend substantially perpendicular to the filtering layers602. Optionally, the attenuating layers604may extend at an angle from the filtering layers602. Adjacent attenuating layers604form air channels618. Optionally, the attenuating layers554may represent interior walls that are semi-permeable and allow airflow therethrough.

FIG. 24illustrates a top view of the filter/sound attenuation bank600. The attenuating layer604form the channel618. The attenuating layers604are arranged parallel to each of the front face609and the back face611. Optionally, the attenuating layers604may extend at an acute angle with respect to the front and back faces609,611. The upstream filtering layer608is positioned perpendicular to the front and back face609,611. Optionally, the upstream filtering layers are positioned at an acute angle with respect to the front and back faces609,611. The first downstream filtering layer610and the second downstream filtering layer612are each positioned at an angle with respect to the front and back face609,611. Optionally, the first and second downstream filtering layers610,612may extend parallel to the front and back faces609,611.

In the exemplary embodiment, the attenuating layer604has a front end620and a back end622. The back end622is coupled to one of the filtering layers602to form an airtight interface. The front end620is rounded. Optionally, the front end620may be rounded, flat, pointed, concave, convex, and/or non-uniformly rounded. The attenuating layers604form the channel618. The channel618directs airflow through an opening and/or perforated portion of the back face611.

FIG. 25is a perspective view of a damper700formed in accordance with an embodiment. The back draft damper700comprises a shell705which defines a central opening702having an inlet701and an outlet703through which air passes. The shell705is constructed to fit into a duct or passageway through which air flows, or be placed immediately upstream or downstream of a fan unit. The size of the shell705depends upon the size of the duct, passageway or fan unit. The shell705is constructed of 16 gauge sheet metal and has a lip located at the outlet703which engages an optional egg crate flow straightener706. The shell705has a top708, bottom709and sides710. The shell705can be rectangular, elliptical, or round. The shell705can be fabricated from many types of materials and have different dimensions based on a particular application.

A plurality of vanes712extend between the top and bottom surfaces708,710of the shell705, The vanes712move between open positions, where air can flow substantially unimpeded through the central opening702, and closed positions, dashed line, where air cannot flow through the central opening. The vanes712have top ends713and bottom ends715, rounded leading edges714and sides716which converge to thinner trailing edges718resulting in a neutral aerodynamic shape which creates little drag due to air flowing over the vanes. The vanes712have a width which is less than or equal to the depth of the shell705and a length which is slightly less than the height of the shell705. Optionally, the vanes712may have any size suitable for use with the shell705. In the exemplary embodiment, the vanes712are configured as a solid attenuating layer. Optionally, the vanes712may be semi-permeable and allow airflow there through. Optionally, the vanes712may include filtering layers. Alternatively, the vanes712may be a combination of attenuating layers and filtering layers. A filter bank720is positioned at the outlet703. Optionally, the filter bank720may be positioned at the inlet701. The filter bank720is coupled to the shell705to form an airtight interface.

The vanes712are rotatably mounted in the shell705such that their axes of rotation726are slightly offset front to back from the vertical at an angle with the tops of the vanes712being closer to the inlet701than the bottoms of the vanes712. The amount of offset depends on the size and weight of the vanes and the amount of airflow that will pass through the damper. The purpose of the offset is to cause gravity to rotate the vanes to their fully closed position when there is no positive airflow through the damper, much in the same manner that a refrigerator door closes. However, the offset should be as little as possible to obtain this result so that the vanes can rotate to their open positions quickly when there is any positive airflow through the shell. Moreover, it is desired to have the vanes become fully opened with as little airflow as possible.

FIG. 26illustrates an attenuating filter800that may be used with the example embodiments above. The attenuating filtering includes an attenuating layer804and a filtering layer802. The attenuating layer804has a front face806and a back face808. The attenuating layer804is semi-permeable and allows airflow therethrough. In the exemplary embodiment, the filtering layer802extends along each side of the attenuating layer804to encase the attenuating layer804therein. Optionally, the filtering layer802extends along only one of the front face806and/or the back face808of the attenuating layer804.

FIG. 27illustrates an attenuating filter850that may be used with the example embodiments illustrated above. The attenuating filtering includes an attenuating layer854and a filtering layer852. The attenuating layer854is semi-permeable and allows airflow therethrough. The filtering layer852has a front face856and a back face858. In the exemplary embodiment, the attenuating layer854extends along each side of the filtering layer852to encase the filtering layer852therein. Optionally, the attenuating layer854extends along only one of the front face856and/or the back face858of the filtering layer852.

FIG. 28shows airflow between the two panels20which represent acoustically insulted surfaces and sound attenuation layers.FIGS. 28-30show a first embodiment in which a fiberglass core22has an open cell foam24layered with at least one side of the fiberglass core22. FIGS.28and30-33show a second embodiment combining the use of open cell foam24with for use of perforated rigid facing26.FIGS. 33 and 34show a third embodiment in which the entire insulation board is replaced with an uncoated open cell foam pad24.

Turning first to the first embodiment shown inFIGS. 28-30, this layered embodiment includes a fiberglass core22(or other type of insulation) that has an open cell foam24layered with at least one side of the fiberglass core22. One advantage to using both the fiberglass material and the open cell foam material is that it is less expensive than using open cell foam material alone because open cell foam more expensive than fiberglass. Another advantage to using both the fiberglass material and the open cell foam material is that it weighs less than using fiberglass material alone because fiberglass weighs more than open cell foam. Another advantage to using both the fiberglass material and the open cell foam material is that is that the two materials provide different types of acoustic insulation over a different range of frequencies. Together, the two materials provide sound absorption over greater range of frequencies. The graph below (shown with a vertical axis as the absorption coefficient going from 0 to 1 and a horizontal axis showing the frequency going from 0 to 10,000 Hz at approximately the peak point) is meant to be exemplary and does not necessarily reflect accurate measurements.

Alternative embodiments of the first layered embodiment include a fiberglass core22with one side layered with open cell foam24(FIG. 28), a fiberglass core22with both sides layered with open cell foam24(FIG. 29), and a fiberglass core22and layered with open cell foam24secured by perforated rigid facing26(FIG. 30). The bottom section ofFIG. 33shows the embodiment ofFIG. 30in use in an exemplary air handler. It should also be noted that an alternative embodiment could include more than two layers of different types of insulation. For example, a four layer version could be open cell foam, fiberglass, rockwool, and open cell foam. The layered embodiment could actually be “tuned” using different types of insulations, different quantities of insulations, and different thicknesses of insulations to have the desired acoustic properties for the intended use.

The embodiments described herein include a method for making an air handler using the panels and layers. The method includes the steps of providing an air handler system with at least one air handler surface, providing a core of first insulation material having at least one layering surface, and providing a facing of open cell foam second insulation material. Then, the facing is at least partially layered to the at least one layering surface to form a layered insulation board. Finally, the at least one air handler surface is at least partially covered with the layered insulation board so that the facing is exposed to airflow through the air handler.

Turning next to the second embodiment shown in FIGS.28and30-33, this perf-secured embodiment combines the use of open cell foam24with for use of perforated rigid facing26. Combining the use of open cell foam and perforated rigid facing provides significant advantages for use in air handlers. For example, the use of the perforated rigid facing26to secure the open cell foam24does not significantly reduce the sound absorption qualities of the open cell foam24. As shown inFIG. 31, the open cell structure of the open cell foam24allows portions of the open cell foam24to protrude from openings defined in the perforated rigid facing26(shown in front view inFIG. 32). The exposed open cell foam24is able to absorb sound waves. In one embodiment, protruding open cell foam24formed between the openings in the perforated rigid facing26absorbs sound waves. This can be compared to prior art embodiments in which sound waves are reflected by the substantially rigid diaphragms formed by the smooth facing being divided by the perforated rigid facing.

Alternative embodiments of the second perf-secured embodiment include a fiberglass core22and layered with open cell foam24secured by perforated rigid facing26(FIG. 30) and non-layered open cell foam24secured by perforated rigid facing26(the bottom section ofFIG. 33). It should be noted that alternative embodiments may replace perforated rigid facing26shown inFIG. 32with alternative securing structure such as perforated rigid facing26with alternatively shaped openings, straps, netting, wire grids, or other securing structure suitable to prevent the open cell foam24from being drawn inward.

The embodiments described herein include a method for making an air handler using the perf-secured embodiment. The method includes the steps of providing an air handler system with at least one air handler surface, providing open cell foam insulation material, and providing securing structure through which said facing may be exposed. Then, the at least one air handler surface is at least partially covered with the open cell foam insulation material. Finally, the open cell foam insulation material is secured to the at least one air handler surface so that the protruding open cell foam insulation material is exposed to sound waves and/or airflow through the air handler.

Turning next to the third preferred embodiment shown inFIGS. 33 and 34, in this uncoated embodiment combines the entire insulation board is replaced with uncoated open cell foam24. This would be particularly suitable for uses in which the presence of fiberglass would not be satisfactory for the intended use or would be unacceptable to the intended client. For example, pharmaceutical companies involved in ingestible or injectable drugs would find it unacceptable to have any fiberglass in the air handler. Alternative embodiments of the second uncoated embodiment include uncoated open cell foam24secured by perforated rigid facing26(FIG. 33) uncoated open cell foam24secured in a frame30(FIG. 34).

FIG. 35is a flowchart of a method900for forming an air handling unit100. At902, a fan array is positioned within the air handling unit. The fan array is configured to channel air through the air handling unit. At904, a filter bank is positioned within the air handling unit to filter the air flowing therethrough. The filter bank may be positioned upstream and/or downstream from the fan array. Positioning the filter bank includes positioning at least one filtering layer, at906. At908, at least one attenuating layer is positioned adjacent the filtering layer. Optionally, the attenuating layer may abut the filtering layer. Additionally, the attenuating layer may be coupled to the filtering layer. At910, the filtering layers and attenuating layers are arranged using at least one of the configurations shown inFIGS. 4-25.

The embodiments described herein are described with respect to an air handling system. It should be noted that the embodiments described may be used within the air handling unit and/or in the inlet or discharge plenum of the air handling system. The embodiments may also be used upstream and/or downstream of the fan array within the air handling unit. Optionally, the described embodiments may be used in a clean room environment. The embodiments may be positioned in the discharged plenum and/or the return chase of the clean room. Optionally, the embodiments may be used in residential HVAC systems. The embodiments may be used in the ducts of an HVAC system. Optionally, the embodiments may be used with precision air control systems, DX and chilled-water air handlers, data center cooling systems, process cooling systems, humidification systems, and factory engineered unit controls. Optionally, the embodiments may be used with commercial and/or residential ventilation products. The embodiments may be used in the hood and/or inlet of the ventilation product. Optionally, the embodiment may be positioned downstream of the inlet in a duct and/or at a discharge vent.