US2957403A

US2957403A - Fire damper control apparatus

Info

Publication number: US2957403A
Application number: US776299A
Authority: US
Inventors: Glenn E Kautz
Original assignee: HH Robertson Co
Current assignee: HH Robertson Co
Priority date: 1958-11-25
Filing date: 1958-11-25
Publication date: 1960-10-25
Anticipated expiration: 1977-10-25

Description

Oct. 25, 1960 G. E. KAUTz 2,957,403

FIRE DAMPER CONTROL APPARATUS /6 INVENTOR. *F* .1 G/enn E Kczuz Z BY @M (f/MM ATTRNEY Oct. 25, 1960 G. E. KAuTz 2,957,403

FIRE DAMPER CONTROL APPARATUS Filed NOV. 25, 1958 4 Sheets-Sheet 2 INV ENTOR.

BYG/e/m E Ka@ 7'2 IZMMGM @Q .ATT ORNE' Y Oct. 25, 1960 G. E. KAu-rz FIRE DAMRRR CONTROL APPARATUS 4 Sheets-Sheet 3 Filed Nov. 25, 1958 INVENTOR. G/e/m E. /1/ auz BY /MZQMM ATTORNEY Oct. 25, 1960 G. E. KAUTz 2,957,403

FIRE DAMPER CONTROL APPARATUS 4 Sheets-Sheet 4 Filed Nov. 25, 1958 INVENTOR. f G/e/m E. /faaz BY MQMJJ@ H TTFNEY corporation of Penn- This invention relates to re damper control apparatus particularly adapted for use in an airconditioning and distributing system.

The invention has for an object to provide novel and improved fire damper control apparatus embodied in an lair conditioning and distributing system wherein a damper normally operative for controlling the discharge of conditioned air is arranged to be automatically closed by the present apparatus in the event of fire.

With this general object in `View and such others as may hereinafter appear, the invention consists in the tire damper control apparatus hereinafter described and particularly defined in the claims at the end of this speciiication.

In the drawings illustrating of the invention;

Fig. l is a front elevation partly in cross section of a oor mounted outlet box forming a part of an air conditioning and distributing system and embodying the present invention;

Fig. 2 is a vertical cross section of the same as viewed from the line 2-2 of Fig. 1;

Fig. 3 is a side elevation of an air discharge duct or stack similar to the stack shown in Fig. 2 with some of the parts in a different position of operation;

Fig. 4 is a View similar to Fig. 3 with the parts shown in another position of operation;

Fig. 5 is a perspective detail view of an operating lever forming a part of the fire damper control apparatus;

Fig. `6 is a side elevation of a modified form of the present re damper control apparatus as embodied in a ceiling mounted outlet box of an air conditioning and distributing system;

Fig. 7 is a similar view showing some of the parts in va different position of operation; and

Fig. 8 is a perspective detail view of the operating lever forming a part of the modied form of the lire damper control apparatus.

ln general the present invention contemplates tire damper control apparatus or operating mechanism ernbodied in an air conditioning and distributing system of the type having an air discharge duct or stack connected to a supply of air and through which air is discharged into an area to be conditioned. The stack is provided with a control damper adapted for use as a fire damper. The present operating mechanism for operating the damper is mounted on the damper shaft in a manner such as to permit normal operation of the damper to control the discharge of air from the stack and is arranged to eiect complete closing of the damper in the yevent of a tire.

The invention is illustrated herein as embodied in an air conditioning system of the ldual duct type wherein air of different condition is discharged through a pair of stacks into the mixing chamber of an outlet box to beA discharged into the room. ln the illustrated embodiment `of the invention only one stack of the dual duct unit is shown since the tire `damper operating mechthe preferred embodiment assigner to H. H. Rohertdamper comprising a 2,957,403 Patented Oct. 25, 1960 anism applied to each stack is similar in construction and mode of operation. In practice each stack is provided with a pair of dampers, one damper controlling the volume of the air delivered from its stack as controlled by a thermostat in the room, and the second pressure reducing damper spaced from the volume control damper and operatively connected to pneumatically operated means responsive to variations in the air pressure between the two dampers for substantially restoring and maintaining a static pressure of a predetermined value in the area between the dampers when variations thereof occur upon operation of the volume control damper or upon increases or decreases in air supply pressure on the upstream side of the pressure reducing damper. 'Such control apparatus forms the subject matter of a copending application, Serial No. 649,355, filed March 29, 1957, by Bernard E. Curran and myself, and only sufficient portions of such control apparatus are herein illustrated and described as will enable the present invention to be understood.

In accordance with the present invention the fire ydamper operating mechanism is operatively connected to one of the dampers in each stack, preferably to the pressure reducing damper, and each operating mechanism is mounted on its damper shaft in a manner such as to permit operation of the pressure reducing damper from an open to a closed position to control the static pressure between the dampers during normal operation of the outlet unit and is arranged to effect complete closing of the damper in the event of a fire. In the illustrated embodiment of the invention the operating mechanism includes a Weighted lever normally maintained in an inoperative position by a fusible link adapted to be melted by the heat of a yfire to release the weighted lever and effect closing of the damper. In one embodiment of the invention the fire damper operating mechanism is shown as applied to a door type outlet unit, and in another embodiment of the invention the operating mechanism is shown as applied to a ceiling type outlet unit.

Referring now to the drawings, and particularly to Fig. 1, one half of a floor type dual duct outlet box 10 is illustrated. The outlet box 10 defines a mixing chamber 11 into which air of different condition, such as hot and cold air, is delivered from similar stacks 12', only one of which is shown, the mixed air being discharged from the outlet box through a discharge opening grille 14 having a suitable lbaflle 16 associated therewith. Each stack is connected to a `different air conducting cell 1S forming a component of a load supporting door through which air of the same 0r `different condition ows from a supply thereof, Each stack is provided with an upper damper comprising a volume control damper 20, and a lower damper comprising -a pressure reducing damper 22.

A single thermostatically controlled air motor 24 is used to operate corresponding volume control dampers 20 in adjacent stacks 12, the air motor being actuated by a room thermostat 26 which acts as a valve between a ycompressed air line 2S and the motor to increase or decrease the air pressure to the motor in accordance with the room temperature. The -air motor 24 is connected by an arm 30 to a shaft 32 which carries the volume control damper 20 in each stack, the dampers being arranged at right angles to each other so that rotation of the shaft in one direction will close the hot air damper and open the cold air damper, and conversely, rotation of the shaft in the opposite direction will open the hot air damper and close the cold air damper.

The pressure reducing damper 22 is -arranged tobe actuated by a pneumatically operated static pressure regulator indicated generally 4at 34 which is responsive' to variations in lair pressure between the upper and

lower dampers

20, 22 and is arranged to effect adjustment of the pressure reducing damper 22 in a manner such as to compensate for such variations. As herein shown, the pressure reducing damper 22 is mounted Vfaston an individual shaft 36, one end of which is provided with a clevis 38 secured to the shaft by a set screw 40. A rigid end plate 42 having a right angle extension 44 at its lower end is secured to the underside of the clevis by a screw 46. It will be noted that one side of the clevis is defined by an angular surface 48 extending from the upper portion thereof at an angle of about forty-five degrees to a point adjacent the inner corner defined by the end plate `42 and its right angle extension 44 as shown in Fig. 2. The plate 42 is connected to one end of a bellows 50, which may comprise a pleated structure of thin flexible material, and the other end of the bellows is connected to a fixed end plate 52 supported from the stack by lugs 54, as seen in Fig. l. The fixed end plate 52 is connected by an air tube 56 to the upper end of the static pressure regulator 34. The static pressure regulator is also provided with a static pressure sensing opening 58 in communication with the interior of the stack at a point between the two

dampers

20, 22 and is further provided with an air pickup tube 60 at the lower end thereof extended into the path of the air supply on the upstream side of the damper 22 and which is arranged to communicate with the air tube 56 to effect inflation of the bellows 50 in response to an increase in the static pressure between the

dampers

20, 22.

The bellows 50 is normally urged into the deflated position shown in Fig. 2, in which position the damper 22 is fully open, by a coil spring 62 wound about the other end of the shaft 36, one end of the spring being fixed in a collar 64 adjustably mounted on the shaft 36, the other end of the spring being fixed in a bearing hub 66 formed on the stack. Since the static pressure regulator, per se, does not form a part of the present invention, it is believed sufficient to state that in operation any pressure increase occurring between the

dampers

20, 22 is sensed by the static pressure regulator through the sensing opening 58, and when an increase in the pressure is detected air is permitted to enter the tube 56 to inflate the bellows and effect rocking of the shaft 36 and damper 22 in a closing direction against the tension of the coil spring 62 in an amount proportionate to the increase in pressure so as to restore the static pressure between the dampers to a predetermined value, thus tending to maintain a constant pressure and stable flow of the conditioned air into the mixing chamber 11 and through the outlet grille 14.

In accordance with the present invention, provision is made for mounting the fire damper control apparatus or operating mechanism indicated generally at 70 on the pressure reducing damper shaft 36 in a manner such as to permit opening and closing of the pressure reducing damper 22 during normal operation, as above described, and in the event of a fire to effect positive rocking of the sha t 36 in a direction to close the damper against the urging of the coil spring 62 and irrespective of the normally adjusted position of the damper. As illustrated in Figs. l and 2, the fire damper operating mechanism 70 includes a lever 72 pivotally or floatingly mounted on the shaft 36, the outer end of the lever being provided with a weight '74, herein shown as a cylindrical section of metal. The weight 74 is normally supported in an elevated position, as shown in Fig. 2, by a fusible link 76 connected at its upper end to an opening in an anchorclip 78 hooked over the upper edge of the stack 12, and connected at its lower end to a hook 80 secured to the weight 74.

As shown in detail in Fig. 5, the lever 72 comprises a bent rod provided with spaced

circular loops

82, 84 at its pivotal end, the loops being joined by a cross bar 86. As seen in Fig. 1, the loops t loosely over the shaft 36 and are disposed one on each side of the clevis 38 with the cross bar 86 extending across in front of the angular surface 48 of the clevis when the lever 72 is supported in its upraised or inoperative position as shown in Fig. 2. Thus, it will be seen that in normal operation the shaft 36 and its clevis 38 is free to move in a counterclockwise directionV through ninety degrees when the bellows is inflated to move the damper 22 from a fully open position, as shown in Fig. 2, to a fully closed position in response to the static pressure regulator 34 and against the tension of the coil spring 62. The bellows is shown in a partially ini-lated position in Fig. 3 wherein the angular surface 48 has moved away from the cross bar 86 which is maintained in its inoperative position during normal operation of the damper 22. It will be observed that a stop screw 88 is provided in the stack which extends through a wall of the stack into the path of one edge of the damper 22 to limit the movement thereof into a horizontal or fully closed position.

In operation, in the event of a fire, the fusible link 76 will be melted to release the weighted lever 72 which is rocked by gravity in a counterclockwise direction to engage the cross bar 86 with the angular surface 48 of the clevis 38, thus forcibly rocking the shaft 36 and damper 22 against the tension of the spring 62 to close the damper as shown in Fig. 4. While the cross bar 86 is conveniently arranged to engage the substantially radially extended surface 48 of the existing clevis 38 it will be understood that the cross bar 86 may cooperate with any similar projection from lthe shaft 36.

Referring now to Figs. 6, 7 and 8, in a modified form of the invention, the pres'ent fire damper operating mechanism, indicated generally at 90, is illustrated as embodied in a ceiling outlet stack 92 comprising an inverted version of the floor mounted unit shown in Figs. l to 4. The structure and mode of operation of the inverted stack 92 is the same as for the upright stack, and as herein shown, the inverted stack is connected to the lower wall of the air conducting iioor cell 18 shown in broken lines in Fig. 6. The stack 92 may comprise one of a pair of stacks enclosed within an outlet box 94 also shown in broken lines. The modied form of fire damper operating mechanism includes a similar pivotally mounted lever 96, as shown in detail in Fig. 8, provided with spaced loops' 98 loosely tted over the damper shaft 100 and straddling the clevis 102 with the cross bar 104 arranged to engage the :angular surface of the clevis 102 fast on the shaft 100. The free end of the lever 96 is provided with a weight 105 normally maintained in an upraised or inoperative position by a fusible link 106 connected at its lower end to the weight by a hook 108 and connected at its upper end to an anchor bar 110 secured to the upper end of the inverted ceiling unit. In operation it will be seen that when the bellows 112 is inflated under the control of the static pressure regulator L14, the end plate 116 and clevis 102 are free to move in a clockwise direction to rock the shaft and to move the pressure reducing damper 118 from an open to a closed position without interference from the cross bar 104. It will be understood that in the modied form coil spring similar to the coil spring 62 shown in Fig. l is provided to urge the damper 118 into an open position. In the event of fire, the fusible link 106 is melted to release the weighted lever 96 whereupon the cross bar 104 will engage the angular surface 120 of the clevis to rock the shaft 100 in a clockwise direction to fully close the damper. It will be understood that the weight is of sumcient mass to overcome the tension of the spring tending to urge the damper into an open position, and that the damper will come to rest in a horizontal position against the stop screw 122 as shown in Fig. 7.

From the above description it will be seen that the present invention provides fire damper control apparatus or operating mechanism operatively connected to a damper supported in an air delivery duct or stack in a manner such as to permit normal adjustment of the damper to control the ow or the pressure of the air passing therethrough during normal operation, and which is adapted to be rendered operative in the event of a iire to positively close the damper.

While the invention has been herein illustrated and described as embodied in an air conditioning and distributing system having a pressure reducing damper which serves as the fire stop damper in the event of a lire, it will be understood that the invention may be embodied in other forms within the scope of the following claims. Thus, in the broader aspects of the invention it will be apparent that the present operating mechanism may be used with equal advantage when operatively connected to other types of dampers adapted to be either manually or automatically controlled in normal use, and which may be caused to be positively closed by the present operating mechanism in the event of fire.

Having thus described the invention, is'

what is claimed 1. In an air conditioning and distributing system, an air delivery stack, a damper shaft having a damper fast thereon and operating in said stack, means operatively connected to said shaft for normally opening and closing said damper including means for resiliently urging the damper into an open position, independently operated and normally inoperative damper closing means including a. weighted lever pivotally mounted on said damper shaft, a projection on said shaft, and a fusible element supporting said weighted lever in its inoperative position and out of contact with said proiect'on during normal opening and closing of the damper, said weighted lever being released upon melting of said fusible element in the event of a tire to engage said projection and eiect rocking of the shaft and closing of the damper against the force of said resilient opening means.

2. An air conditioning and distributing system as defined in claim 1 wherein a stop is provided in the stack to limit the movement of the damper in a closing direction.

References Cited in the tile of this patent UNITED STATES PATENTS