AU654342B2 - Thermally actuated diffuser - Google Patents

Description

.1 65434

AUSTRALIA

Patents Act 1990 2 /00/0011 Regulation 3.2 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

a a a a a., as.

a @500 atasa Name of Applicant: ACUTHERM LIMITED Actual Inventor(s): James Robert KLINE and Robert Stephen HUNKA Address for service in Australia: CARTER SMITH BEADLE Qantas House 2 Railway Parade Camberwell Victoria 3124 Australia Attorney Code CD saI t a C Cli C Invention Title: THERMALLY ACTUATED DIFFUSER t The following statement is a full description of this invention, including the best method of performing it known to us: Our Ref: #10636 JRG:WB 04-15acu i ;i i~ SI A -la- FIELD OF THE INVENTION This invention relates to a novel diffuser unit for a conditioned air system. More specifically, this 5 invention relates to a thermally actuated diffuser system for delivering a variable or modulated volume of air to *4 a room or other occupiable space.

BACKGROUND OF THE INVENTION

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L Most conditioned air distribution systems are designed to vary either the volume of the conditioned air or the temperature of the conditioned air in response to a change in room air temperature. There has been some h t tendency in conditioned air distribution systems toward variable air volume systems because variable air volume systems offer a number of potential operating and cost advantages, as compared to constant volume, variable temperature systems.

Variable air volume systems appearing in the past typically include a thermostat for sensing the air temperature of the room. The thermostat is usually .i located in a position which is remote from the conditioned air outlet. In such systems, the thermostat is connected to an auxiliary system, such as a pneumatically powered operator, located in or near the conditioned air outlet. The auxiliary system is used 1

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o o o arr *r 9 9, 9 9 i rE -2to open or close the damper in the branch duct, in response to a detected change in room air temperature, to control the passage of conditioned air from the duct.

These prior variable air volume systems, however, have presented a number of problems. Variable air volume systems are somewhat complex to install due to the external wiring connections between the remotely located thermostat and the auxiliary operator system. In addition, the auxiliary operator contributes to the complexity, size, and cost of these particular air distribution system.

In order to alleviate the problems associated with remotely placed thermostats, thermally powered diffusers have been designed which have sensor-actuators that act both as thermostats and operators, and are mounted to the diffuser. One such diffuser, as disclosed in United States Patent No. 4,231,5133 issued on November 4, 1980 and reissued June 1, 1982 as Reissue No. 30,953, includes an integrated thermal sensor-actuator which tracks room air temperature. During a cooling mode of operation, if the room becomes too warm, the sensor-actuator may deliver an actuating force to an air flow control portion of the diffuser to increase the amount of cool duct air flowing into the room. This diffuser further includes a second integrated sensor-actuator which measures the duct air temperature and, during a heating mode of operation, may provide an actuating force to the air flow control portion to increase the flow of warm air into the room. In this manner, the thermally actuated diffuser controls the volume of air delivered to the room to maintain a comfortable room temperature.

An improved thermally actuated diffuser, as disclosed in United States Patent No. 4,523,713, includes a third sensor-actuator which, in combination with the above- -3described first sensor-actuator, responds to changes in room air temperature. Broadly, the interaction of the sensor-actuators of this improved diffuser translates into movement of louvers or blades of the diffuser between a fully open and a fully closed position to control passage of air from the duct to the room.

One problem which has been encountered with thermallypowered diffuser systems is that the maximum diffuser opening is often too large, resulting in discharge velocities that are too low. The velocity of discharge from a diffuser is particularly important in order to achieve the desired "throw" and to insure that the Coanda effect is realized. Throw is the distance from the diffuser at which the velocity of discharged air is o 0 v a 15 feet per minute. The Coanda effect is a hugging of the 0oo Sooo ceiling by the discharging air stream, rather than o o0000 o0 detachment and downward or localized dumping of the air.

9 0 0000 .000 For an integrated system which is properly designed and .O engineered the maximum diffuser opening will be limited to match the volume of the supply air to produce the desired velocity of discharged air for the targeted diffuser throw and Coanda effect. For conditions o0 0 0 04D existing at the site and to accommodate asymmetrical o00o installations, it is highly desirable to be able to perform field adjustments of the diffusers to enable 0a setting or varying the maximum size of the diffuser discharge opening to adjust diffuser velocity and throw.

0 Problems also have arisen in thermally-powered diffusers in connection with both room air induction and influence of 11is room air sensor-actuators by heating or cooling of the diffuser parts by the duct air. In order to accurately modulate duct air flow into the room.

Thermally-powered diffusers require sufficient induction of room air into the diffuser to accurately track or -4follow changes in the room air temperature. Thus, a minimum level of room air which has not been influenced by the duct air temperature is required across the room Tair sensor-actuators for accurate tracking. Poor air induction or adulteration of the room air temperature by the duct air decreases the performance and accuracy of such thermally actuated diffusers.

Accordingly, it is therefore a general object of the invention to provide a thermally actuated diffuser system which is highly efficient and accurate and which will obviate or minimize difficulties of the type previously described.

It is a specific object of the invention to provide a rr w thermally actuated diffuser which accurately tracks the 1 4 15 change in temperature of ambient air in a room and can be field adjusted to maintain the volume of duct air being discharged at maximum diffuser opening at a level rr producing the desired diffuser throw.

Another object of the present invention is to provide a thermally-powered diffuser having improved room air induction for more accurate tracking of room air temperature.

Still a further object of the present invention is to C provide a thermally-powered diffuser which is less influenced by duct air temperature.

9 9 Another object of the present invention is to provide a thermally-powered diffuser which is durable, easy and inexpensive to operate, and can be retro-fit into a wide range of existing air distribution networks.

L. n, ci; mn i 00 DISCLOSURE OF THE INVENTION According to one aspect of the invention there is provided a diffuser for regulating the flow of air from a duct to a room or other space, said diffuser comprising: air flow control means for varying the size of an opening in said diffuser to regulate the flow of air from said duct into the room or other space; sensor-actuator means responsive to both room air temperature and duct air temperature and operatively associated with said air flow control means to move said air flow control means between an open mode of operation and a closed mode of operation in response to changes in room air temperature with respect to duct air temperature; and room air induction means mounted proximate said sensor-actuator means and 0"0 having induction nozzle means formed for discharge of duct air therefrom :independently of the discharge of duct air from said air flow control mean' to induce oo00. room air flow past a portion of said sensor-actuator means.

0 15 The room sensor-actuators may be positioned closely proximate an inlet side of an induction air passageway to minimise the corrupting affect of heating and cooling 000 of the diffuser components by the duct air.

At least one adjustable stop mechanism may be positioned on the air flow control portion of the diffuser to limit the movement of the air flow control blades to a 20 maximum open operating position which ensures that the discharge velocity from the diffuser is controlled to produce the desired diffuser throw.

BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 is a partially broken away, bottom plan view of a thermally actuated diffuser installed in a modular ceiling in accordance with a preferred embodiment of the subject invention; 23 AugUsl 1994 I I I -6- FIGURE 2 is a fragmentary, side elevation view in cross section of the subject thermally actuated diffuser, taken substantially along line 2-2 in FIGURE 1; FIGURE 3 is a partially broken away, enlarged, bottom plan view of the subject thermally actuated diffuser; FIGURE 4 is a side elevation view, in cross section, taken substantially along line 4-4 in FIGURE 3; and FIGURE 5 is a side elevation view, in cross section, taken substantially along line 5-5 in FIGURE 3.

BEST MODE OF CARRYING OUT THE INVENTION Referring now to the drawings, wherein like numerals indicate like parts, and initially to FIGURES 1 and 2, o there will be seen an embodiment of the subject o0r invention. More particularly, a thermally actuated 15 diffuser, generally indicated 10, is shown mounted in a modular ceiling in place of one of the modular panels 12 in accordance with a preferred embodiment of the invention. The diffuser 10 controls the distribution of a variable volume of air from a branch duct 14 i 20 (FIGURE 2) into a room or other open space in response to changes in room air temperature, as will be described SD in more detail below.

I e The diffuser 10 includes a diffuser housing 15, an appearance panel 16, and a diffusion plate 18. Diffusion plate 18 is mounted to housing 15 by brackets (not shown). Diffusion plate 18 sLerves as a plate for directing duct air flow, as well as a support structure for the operative components of the diffuser. Duct air flowing from branch duct 14, as shown by arrows DA, is deflected by diffusion plate 18 and directed outwardly to the periphery of diffuser housing 15 for subsequent flow along the inner surfaces 20 of the inclined _i

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0000 0 0 S0000 0000 0 000 #000 00 00O 0 0 (o

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sidewalls of housing 15. Duct air, DA, leaving the periphery of diffuser housing 15 is directed at an angle 8 (usually between about 30 degrees to about 35 degrees) with respect to the adjacent ceiling panels 12 to provide a maximum Coanda effect, to cause the diffused air to hug the ceiling and avoid dumping.

In order to accurately track or follow the room air temperature, the diffuser of the present invention advantageously employs room air induction means which induces a certain amount of room air, shown by arrows RA, to flow upwardly and between appearance panel 16 and diffusion plate 18. The space between appearance plate 16 and diffusion plate 18 acts as an induction passageway means, generally designated 11, in which a thermal 15 sensor-actuator assembly, generally designated 22, is positioned. Sensor-actuator assembly 22 includes a first thermal sensor-actuator 24, a second thermal sensoractuator 26, and a third thermal sensor-actuator 28.

The first and third thermal sensor-actuators 24 and 28 are mounted below diffusion plate 18 and are therefore positioned in room air induction passageway 11. Second thermal sensor-actuator 26 is mounted above diffuser plate 18 and senses and is responsive to duct air temperature. The first and third thermal sensoractuators, therefore, track the room air temperature, while the second thermal sensor-actuator monitors the duct air temperature.

The first, second, and third thermal sensor-actuators can be of the type commonly used in automotive applications, such as the type distributed by Robertshaw Controls Co. (Fulton Sylphon Division). The interaction of the components of sensor-actuator assembly 22 controls the operation of diffuser 10 to modulate the volume of conditioned air distributed to the room, as will be described in more detail in conjunction with FIGURES

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i -8- Turning now to FIGURE 2, the volume of duct air discharged from the diffuser is controlled by four louvers or blades 32, which are connected by hinges 34 to diffusion plate 18. Spokes 36 connect liCuvers 32 to a louver diffuser control disc 38 which is rotatably mounted to diffusion plate 18 by shaft 40 and locking nut 42. Sensor-actuator assembly 22 controls movement of louver control disc 38, which may rotate in either a clockwise or counterclockwise direction (as shown by broken lines in FIGURE 1) about center shaft depending upon whether the diffuser is operating in a heating mode or cooling mode. Rotation of louver control disc 38 controls the opening and closing of louvers 32.

More specifically, when control disc 38 rotates in S 15 response to an actuating force delivered by sensoractuator assembly 22, each spoke 36 pulls an associated 0o00 °ooo" louver 32 downward away from inner surface 20 of the 0 0.0 sidewalls of housing 15. Duct air may then flow or discharge into the room.

o The diffuser of the present invention is constructed to accurately maintain the desired temperature in the room by providing for induction of uncorrupted or uninfluenced 000o room air into the diffuser and past the first and third 0.0 (room) thermal sensor-actuators 24 and 28, respectively.

O 0 0 0 0 25 This is accomplished by providing an enhanced room air induction means and by positioning both room air sensor- 4 4 actuators closely proximate the inlet side of induction passageway means 11. As shown in FIGURES 1 and 2, the 0room air induction means is provided by one or more nozzles 58 which extend through diffusion plate 18 and SI discharge duct air, DA, in a direction away from sensor- Si actuators 24 and 28. As seen in FIGURE 1, duct air is discharged from two nozzles 58 arranged in a substantially horizontal and parallel orientation which causes room air to be induced in an inlet side 17 of passageway 11 and urged by duct air from nozzles 58 a~ -9across the diffuser and toward an outlet side 19 of passageway 11.

Thus, even when louvers or blades 32 are fully closed and little or no duct air is entering the space being heated or cooled, air induction nozzles 58 will discharge duct air in passageway 11 in an orientation tending to induce or pull air into the passageway and past the room air sensor actuators 24 and 28.

Additionally, and in order to minimize the adverse or corrupting influence which the duct air has on the accuracy of tracking of the room air temperature, it is a further feature of the present invention to position the room air sensor-actuators closely proximate inlet o o 0 S° side 17 of room air induction passageway 11. As may be *o"o 15 seen from FIGURE I, both sensor-actuator 24 and sensoro actuator 28 are positioned very close to inlet side or coo* edge 17 of appearance plate 16. Induced incoming roon air, therefore, passes almost directly over thermal oo sensor-actuators 24 and 28 before the room air has an opportunity to be significantly heated or cooled by the diffuser components which have been continuously subjected to and tend to assume the temperature of the 0 00 0' duct air. There still is some conduction and radiation 0004 0 to the room air sensors from the diffuser components, but placement of the room air sensors closely proximate inlet 17 significantly enhances tracking accuracy.

9%1 4 r cr rt r (~11 It should be noted that other air induction means can be employed in the diffuser of the present invention.

Thus, air induction scoops can be employed in which room 3D air is induced into passageway 11 as a result of the venturi effect created by the discharge of duct air at the periphery of the diffuser along one side of a scoop or induction structure. Such scoop induction structures L-ll~ i I y P. are well-known in the art and will not be described in more detail in this application.

It is an important feature of the diffuser assembly of the present invention to be able to control the maximum velocity of discharge of air from the diffuser, and particularly to be able to adjust the same in the field to aLccommodate actual space heating and cooling requirements. Typically, it is desirable to discharge air from a diffuser at a velocity of about 1000 to about 1700 feet per minute. Velocities below about 1000 feet per minute function, but the throw distance will usually be unacceptably low. Velocities above 1700 feet per minute also are functional, but they tend to produce undesirable noise.

15 A diffuser which has been designed, for example, to be mounted to a 12 inch diameter duct frequently will be mounted instead using a reducer or adapter to a smaller diameter duct, for example an 8 inch duct If pressure control is desired, the adaptation of the 12 inch diffuser to the 8 inch duct will be accomplished by a relief ring (a false neck that provides an annular space between the duct and the relief ring rtrmitting air "o °bypass into the ceiling plenum). If bldSs 32 open to :"ooo a full open position, which position has been designed to produce an air discharge velocity in the range of 1000 ota to 1700 feet per minute for a 12 inch duct, this full open position will be larger than desired for a 8 inch duct, and the discharge velocity of the air will be below the desired minimum of 1000 feet per minute.

In the subject thermally actuated diffuser, therefore, the range of rotation of control disc 38 is limited by stop means 41, which allows control and field adjustment of the discharge velocity of air from the diffuser. Stop means 41 advantageously may be provided by a pair of stop U __lA

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11assemblies 40a and 40b (FIGURE which are positioned radially outwardly of the center of control disc 38.

Stop means 41 includes a tab 43 fixedly mounted to diffusion plate 18 by a nut 46 and a bolt 44 (FIGURE 2).

Stops 40a and 40b can be provided by generally L-shaped members 48 is adjustably mounted to louver control disc 38 on either side of tab 43. Each L-shaped stop member 48 is secured to louver control disc 2R by a bolt 52, which extends through a guide slot 54 formed in control disc 38, and a nut 56. Stop members 48 may be repositioned along slots 54 by loosening bolts 52 and then re-tightening them. Control disc 38 will rotate until one of stop members 48 comes into contact with tab 43. In this manner, the desirable degree of rotation of louver control disc 38 and, therefore, the maximum open operating position of louvers 32, may be set or ti adjusted in the field.

The structural relation between the components of the subject thermally actuated diffuser will now be described in association with FIGURES 2-5. Referring particularly to FIGURE 2, there will be seen first sensor-actuator 24 and third sensor-actuator 28 mounted between appearance panel 16 and diffusion plate 18 for tracking room air temperature, and second sensor-actuator 26 mounted on an opposite side of diffusion plate 18 for monitoring duct air temperature. First thermal actuatorJ 24 has a displaceable piston or shaft 62 which is aligned to engage and displace an elongated L-shaped first member S64. First member 64 is normally biased by a tension spring 68 to rest against a stop 66 mounted to stationary Sdiffusion plate 18. In FIGURE 3, first sensor-actuator 24 is shown in an extended position so that first member 64 has been displaced away from stop 66 by the contact of shaft 62 with a Vertical planar surface of first member 64. Third seisor-actuator 28 (also a room air sensor-actuator) includes a displaceable piston or shaft ~I 4 perne ae 6an ifsonpae1 frtakn It'STR CODE: 23 Jjly 1991 -12which is operable to control rotation of louver control disc 38 through contact with tab 72 mounted to <3 disc 38.

On an opposite side of diffusion plate 18, there will be seen a second member 74 and a third member 76 which have elongated L-shaped configurations similar to first member 64. Second thermal sensor-actuator 26 is mounted directly to third member 76, as shown in FIGURES 2 and and has a thermally displaceable piston or shaft which operably extends to contact a vertical planar surface 77 of second member 74. A torsion spring 78, which is coiled around center shaft 40, biases second member 74 toward third member 76. Torsion spring 78 attempts to rotate second member 74 toward third member Q000 0" 15 76 to rest vertical planar surface 77 of second member 74 against an adjusting screw 80 mounted to third member 76.

o Turning to JRE 4, first member 64 is connected to second member 74 through the outer sleeve 82 mounted on center shaft 40. Third member 76 is fixed to rotate with control disc 38 by shaft 40. Sleeve 82 is free to rotate relative to annular bracket 84 and fixed diffusion plate 18. Bearings 86 permit shaft 40 to rotate within sleeve 82, so that control disc 38 may rotate relative to 25 stationary diffuser plate 18.

Cooling mode .00. In the cooling mode, cool air is supplied from a source, not shown, to duct 14. Since cool air is present in the S;u duct, piston or shaft 75 of the duct sensor-actuator or second sensor-actuator 26, which detects duct air temperature, is in a retracted position. As shaft 75 retracts, second member 74 and its vertical planar surface 77 are rotated toward member 76 carrying duct air sensor-actuator 26 by torsion spring 78, which always tr I i r~-~b~31" i, ~~222< ooo* 0 0 6000 00 0 60 I 0 0 0 00 I0 0 0000 -13seeks to minimize the angular distance between second member 74 and third member 76. Torsion spring 78 acts to bring surface 77 of second member 74 to a rest against one of piston 75 and adjusting screw 80 mounted on third member 76. In the cooling mode shaft or piston 75 will be sufficiently retracted to pull away from surface 77 and cause it to rest on set screw 80. If the room is cool, the shafts of the first and third sensor-actuators: which are both sensing room air temperature, would also be fully retracted. When piston or shaft 62 of first sensor-actuator 24 is in a retracted position, tension spring 68 is able to rotate first member 64 to rest against stop 66 mounted on stationary diffuser plate 18.

It will be seen from FIGURE 4, that member 64 and member 15 74 are fixedly connected to common sleeve 82. Spring 68, therefore, rotates the assembly of member 64, sleeve 82 and member 74 in a counterclockwise direction until the assembly is stopped by stop 66. Member 76 follows the counterclockwise rotation of member 74 by reason of torsion spring 78. As also will be seen from FIGURE 4, control plate 38 rotates with member 76 as a result of being fixedly mounted on common shaft 40. The positions of stop 66 and set screw 80, therefore are selected so that control plate 38 will be in the solid line position 25 of FIGURE 1, or as shown in FIGURE 3, with tab 72 and plate 38 in the middle of its range of travel. This position of control plate 38 causes spokes 36 to simultaneously close the damper blades or louvers 32, as shown in dotted lines in FIGURE 2.

As the room begins to warm up, the thermally responsive wax material in first sensor-actuator 24 begins to expand. Shaft 62 accordingly extends and pushes first member 64 away from fixed stop 66 in a clockwise direction. First member 64 transmits this rotational motion to outer sleeve 82 of center shaft 40. The 0f 00 oBO+ 00 0 000

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i:? r i I i- -i a;i ii k i i ~i ixi ":ii p -14clockwise rotation of outer sleeve 82 causes second member 74 to rotate in a clockwise direction. Such rotational motion is transmitted to third member 76 by torsion spring 78, which causes member 76 to follow second member 74 and causes screw 80 to continue to rest against vertical surface 77 of the second member. The clockwise rotation of third member 76 is, in turn, transmitted through center shaft 40 to control disc 38.

In this manner, the control disc is moved toward the "Open Cooling" position, which opens louvers 32 to an open position, such as is shown in solid line, in FIGURE 2, whereby cool air is supplied to the warming room to cool the room down.

0 oo* The clockwise rotation of control disc 38, however, is 15 limited by stop mechanism 40b, which prevents control o^o a disc from rotating a sufficient amount to fully open louvers 32. The size of the maximum discharge opening 0 is set in the field, as described above, to produce the desired discharge velocity. Additionally, it should be noted, that limiting opening of blades 32 prevents the blades from being displaced against the appearance panel, which would undesirably restrict the flow of induced room o o poo* air in passageway 11. This problem also can be o" eliminated by providing a perforated appearance panel, 25 which is common in the industry and suitable for use in the diffuser of the present invention.

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O 8o 06 a 0 It should be noted that if stop assembly 40b stops clockwise rotation of control plate 38, the clockwise rotation of member 76 will also be stopped. This does 30 not bind the assembly, however, since member 74 will simply rotate away from member 76 against the torsion spring. Set screw 80 will simply come out of contact with surface 77. When the demand for cool air in the room is satisfied, piston or shaft 62 of first thermal actuator 24 will retract, bringing first member 64 to Li i i CL i i Cl~ i- e I~-QLi ILC- rest against stop 66 and bringing second member 74 and surface 77 back into contact with set screw 80. The above-described motion will reverse until control disc 38 is again at the "Closed" position.

Heating mode In the heating mode, warm air is supplied through the duct. This warm air heats the duct second or sensoractuator 26, which causes piston or shaft 75 to extend.

If the room air is cool, the pistons of the first and third thermal actuators will be in retracted positions.

In this case, since shaft 62 of first thermal actuator 24 is retracted, first member 64 will be positioned against stop 66. This positioning of first member 64 o0 causes second member 74 to be rotated to its most counter-clockwise position by sleeve 82. As duct air temperature sensing piston 75 extends from second sensoractuator 26 in response to the warm duct air, third o; member 76 pushes away from second member 74 against the o force of torsion spring 78 in a counterclockwise direction. This counterclockwise rotation of third member 76 rotates center shaft 40 which, in turn, moves control disc 38 in a counterclockwise position to the o S "Open Heating" position, opening louvers 32 to permit 0 04 0 the passage of warm air into the room. Rotation of control disc 38 continues until stop mechanism prevents further counterclockwise rotation.

As warm air continues to be supplied through duct 14 to a0 the room, second thermal actuator 26 continues to expand.

Stop assembly 40a prevents opening of blades 32 beyond the denired size of opening for controlled maximum air discharge velocity. Since stop 40b also prevents any further rotation of control disc 38 in a counterclockwise direction, third member 76 cannot rotate in a counterclockwise direction away from second member 74.

Consequently, second member 74 is pushed by piston

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9! I -16away from third member 76 in a clockwise direction against the force of torsion spring 78. As a result, first member 64, which is connected to second member 74 by outer sleeve 82, is rotated away from tab 66 against the force of spring 68. This causes disengagement of first member 64 from shaft 62 of first thermal actuator 24, but the sensor-actuator assembly does not bind or apply pressures to the sensor actuators which could cause failure.

As the room temperature warms, the thermally expansive material in first and third sensor-actuators 24 and 28 begins to expand. Pistons 62 and 70 begin to extend.

Shaft 70 pushes against tab 72 and moves control disc o°°0 38 from the "Open Heating" position toward and eventually 0000 o- 15 to the "Closed" position. Since neck member 26, in the n©oo 00 heating mode, rotates member 74 in a clockwise direction, 00 ago, member 64 will be out of contact with piston 62 during 0000 0 ooo0 room warming.

a0 In the event the room cools down, shaft 70 of third thermal actuator 28 would retract, permitting control disc 38 to rotate in a counterclockwise direction to open o 0 louvers 32 and to release warm air from the duct into 000 the room. Modulation to close damper blades 32, therefore is being controlled solely by third sensor- 0000 25 actuator 28.

After reading and understanding the foregoing inventive 0 0 o° 0thermally actuated diffuser, in conjunction with the drawings, it will be appreciated that several distinct advantages of the subject invention are obtained.

Without attempting to set forth all of the desirable features of the instant thermally actuated diffuser, at least some of the major advantages include the unique combination of adjustable stop assemblies 40a and L mounted between diffuser plate 18 and louver control disc 38 for limiting the rotation of control disc 38, thereby allowing an optimum open operating position of louvers 32 for control of the diffuser discharge velocity and thereby the diffuser throw. This insures that discharge velocities at maximum opening will be in the desired 1000 to 1700 feet per minute range in both heating and cooling modes. It should be noted that in some installations cooling and heating volume capacity may not be the same and/or optimum throw and Coanda effects different. Thus, stop assemblies 40a and 40b are independently adjustable to produce optimum discharge velocities in both modes.

Moreover, diffuser 10 further advantageously includes air induction means, preferably nozzles 58, which serve 15 to maintain a sufficient stream of room air across first 0. thermal actuator 24 and third thermal actuator 28 to enable accurate room air temperature tracking.

Additionally, room air sensor-actuators 24 and 28 are t t S64positioned proximate an inlet side 17 of air induction passageway 11 to reduce corrupting heating and cooling of the room air by the diffuser components. Accordingly, thermally actuated diffuser 10 is able to be adjusted in the field and is able to operate efficiently in heating and cooling modes to thereby increase energy savings and reduce operating costs.

t U In describing the invention, reference has been made to a preferred embodiment and illustrative advantages of the invention. Those skilled in the art, however, and familiar with the instant disclosure of the subject invention, will recognize additions, deletioiis, modifications, substitutions, and other changes which will fall within the purview of the subject invention and claims.

The claims form part of the disclosure of this specification.

Claims (14)

1. A diffuser for regulating the flow of air from a duct to a room or other space, said diffuser comprising: air flow control means for varying the size of an opening in said diffuser to regulate the flow of air from said duct into the room or other space; sensor-actuator means responsive to both room air temperature and duct air temperature and operatively associated with said air flow control means to move said air flow control means between an open mode of operation and a closed mode of operation in response to changes in room air temperature with respect to duct air temperature; and 0,0* room air induction means mounted proximate said sensor-actuator do o means and having an induction nozzle means formed for discharge of reoo duct air therefrom independently of the discharge of duct air from o said air flow control means to induce room air flow past a portion 15 of said sensor-actuator means.

2. A diffuser as defined in claim 1, and o a s Sadjustable stop means positioned for and limiting the movement e of said air flow control means to a selected maximum open position to control the rate of discharge of duct air from said diffuser at said maximum open position.

3. A diffuser as defined in claim 2 wherein, said stop means limits movement of said air flow control means for both a cooling mode and a heating mode of operation. 'r I N4- r'i~ 23 August 1994 -J: 19

4. A diffuser as defined in claim 3 wherein, said stop means includes two independently adjustable stop assemblies.

A diffuser as defined in claim 1 wherein, said room air induction means includes an induction passageway means, and said portion of said sensor-actuator means being positioned in said induction passageway means, and said induction nozzle means communicating and discharging duct air into said induction channel 10 means in a direction away from said portion of said sensor-actuator g"o means.

6. A diffuser as defined in claim 5 wherein, said passageway means includes an inlet side; and a7 6. A diffuser as defined in claim 2 wherein, said portion of said sensor-actuator means includes a pluralitioned closelynsor- actuator elements and a plurality of movement communicating members mounted to provide override protection to prevent binding and overstressing of sensor-actuator elements upon stopping of the *movement of said air flow control means by said stop means. 15 proximate said inlet side of said passageway means. oe S,

7. A diffuser as defined in claim 2 wherein, [said sensor-actuator means includes a plurality of sensor- l actuator elements and a plurality of movement communicating members mounted to provide override protection to prevent binding and overstressing of sensor-actuator elements upon stopping of the movement of said air flow control means by said stop means. i i 20

8. A diffuser as defined in claim 2 wherein, said stop means is positioned to limit discharge velocity from said diffuser at said maximum open position to between about 1000 and about 1700 feet per minute.

9. A diffuser as defined in claim 1 wherein, said sensor-actuator means includes first sensor-actuator means positioned to be responsive to room air temperature and operatively associated with said air flow control means to modulate the size of said opening by moving said air flow control means in response to changes in room air temperature, second sensor-actuator means positioned to be responsive to duct air temperature, and third sensor- Soo. actuator means positioned to be responsive to room air temperature O and operatively associated with said air flow control means to Smodulate the size of said opening by moving said air flow control means in response to changes in room air temperature; and Il. said second sensor-actuator being formed to disassociate at least o one of said sensor-actuator means and said third sensor-actuator means from said air flow control means in response to and as determined by 000 Sa sensed duct air temperature present in said duct to control the flow 0 0 o of air from the diffuser into the room or other space. A diffuser as defined in claim 1 wherein, j said room air induction means including passageway means having an inlet and an outlet; and said portion of said sensor-actuator means being mounted in said passageway means closely proximate said inlet.

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11. A diffuser as defined in claim 10 wherein, said induction nozzle means includes at least one nozzle communicating duct air into said passageway means in a direction away from and downstream of said portion of said sensor-actuator means.

S2. A diffuser as defined in claim 1 wherein, said room air induction means includes a channel for flow of room air therethrough; said sensor-actuator assembly includes at least two room air temperature sensor-actuators positioned in said induction channel and 0 a duct air temperature sensor actuator positioned in said diffuser to sense duct air temperature; S, said duct air temperature sensor-actuator being mounted and said sensor-actuator assembly being formed to selectively couple one of said two room air temperature sensor-actuators to move said flow control means when said duct air temperature sensor-actuator senses relatively warm duct air, whereby said one of said two room air temperature senu.or-actuators moves said flow control means as said one of said two room temperature sensor-actuators tracks the temperature of room air induced and flowing in said air induction 1, 'o0 channel; and said duct air temperature sensor-actuator being further mounted and said sensor-actuator assembly being formed to produce selective 1 coupling of the other of said room air temperature sensor-actuators to move said flow control means when said duct air temperature sensor- actuator senses relatively cool air, where by said other of said two p Ii a a a+ a air' at 22 room air temperature sensor-actuators move said flow control means as said other of said two room air temperature sensor-actuator tracks the temperature of room air induced and flowing in said air induction channel means.

13. A diffuser assembly as defined in claim 12, and stop means positioned for and limiting the movement of said air flow control means to a maximum open position less than a fully open position of said flow control means.

14. A diffuser substantially as hereinbefore described with reference to the accompanying drawings. DATED: 23 August 1994 CARTER SMITH BEADLE Patent Attorneys for the Applicant: ACUTHERM LIMITED ii ABST&-. T A diffuser (10) for regulating the flow of air from a duct (14) into a room or other space. The diffuser includes air flow control blades (32) for varying the size of the diffuser discharge opening. A thermal sensor-actuator assembly (22) is operatively connected to the flow control blades (32) to move the blades between open and closed positions in response to changes is sensed room air temperature. A duct air sensor-actuator (26) enables the appropriate room air sensor-actuator (24 or 28) to control movement of the blades (32) depending upon whether the duct air sensor-actuator (26) senses relatively warm or relatively cool duct air. An adjustable stop assembly (41) allows field setting of the maximum open position of the control blades for control of the diffuser I discharge velocity. A room air induction passageway (11) and induction nozzle assembly (58) also are provided. The room air induction system (11; 58) permits accurate tracking of room air temperature by the thermal sensor-actuator assembly (22). i:: 4 *f