US2311374A

US2311374A - Automatic fire control system for ventilating or air conditioning systems

Info

Publication number: US2311374A
Application number: US238148A
Authority: US
Inventors: Paul M Farmer; Francis C Evans; Richard F Spamer
Original assignee: American District Telegraph Co
Current assignee: American District Telegraph Co
Priority date: 1938-11-01
Filing date: 1938-11-01
Publication date: 1943-02-16
Anticipated expiration: 1960-02-16

Description

Feb. 16, 1943. P. M FARMER ETAL AUTOMATIC FIRE CONTROL SYSTEM FOR YENTILATING 1938 2 Sheets-Sheet 1 OR AIR CONDITIONING SYSTEMS Filed Nov.

FIG. I

INVENTORS P. M. FARMER F.C.EVANS BY R.F.$PAMER 1 ATTORNEY IH'H H 2,311,374 AUTOMATIC FIRE CONTROL SYSTEM FOR VENTILATING Feb. 16, 1943. P. M. FARMER ETAL OR AIR CONDITIONING SYSTEMS 2 Sheets-Sheet 2 Filed Nov. 1, 1938 FIG. 4

1 69 E l se 70 607- i 13 l l J I l l l l l l l l l IIMHWIIHIIII FIG. 6

INVENTORS P.M.FARMER F. C. EVANS R.F.-SPAME 4 ATTORNEY Patented Feb, 16-, 1943 AUTOMATIC FIRE CONTROL SYSTEM FOR R AIR. CONDITIONING Paul M. Farmer, Maplewood, N. J., and Francis 0. Evans, Dongan Hills, Staten Island, and Richard F. Spamer, Lynbrook, N. Y., assignors to The American Di strict Telegraph Company,

New York, N. Y., a corporation of New Jersey Application November 1, 1938, Serial No. 238,148

9 claims;

This invention pertains generally to systems for conditioning air, for'ventilating enclosures, and for warm air heating. Reference hereafter is made to such systems by the expression air conditiomng system, which should be taken to mean vide an air conditioning system with a means for any system for the positive circulation of air automatically disabling the air conditioning sys in or to an enclosure, for the purpose of ventllatem under predetermined conditions, as, for extion and/or heating, cooling or otherwise treatample, upon the occurrence of fire or'smoke withing the air in the enclosure. The invention perin the enclosure or within the air conditioning tains more particularly to fire protection devices system itself, to prevent smoke damage andialso and systems for protecting air conditioned premallow the proper operation of the usual fire'jproises against fire, for enabling more positive and tection system. i reliable operation of the usual fire protection de- A further object of this invention is to provide vices by controlling circulation of air through an a fire detecting means within an air conditioning air conditioning system, and to limit the spread 5 system for disabling said system and thereby alof fires. lowing. the proper operation of a sprinkler system. Air conditioning has created new problems in Another object of this invention is to provide fire protection in that air impelled into an enin an air conditioning system a smoke detector closure at the high velocities necessary in air confor detecting the passage 01' smoke within the duct ditioning systems, especially airthat is cooler '20 system for the purpose of controlling dampers than existing ambient temperature will prevent and fans within the system to prevent circulation the proper operation of automatic sprinkler sysof air therein. terns, of thermostatic fire detecting systems, par- Another object of the invention is to detect fire ticularly those of the fixed operating-temperaor smoke being drawn into an air conditioning ture type, and of fire detecting or control apparasystem through the fresh or outside air intake tus. For instance, a sprinkler head located near of the system, such outside fires being known as the outlet of a cold air duct is prevented from xp sure fires, and to control dampers'and fans operating when a fire occurs directly underneath to prevent the drawing in of such fire or'smoke. it owing to the high velocity circulation of cold Another object of the invention is to "close the air which may blow the heat and flame away 0 dampers in Su h Sequence and with such timing from the proper sprinkler, while on the other that air conditioning system ducts are 'not damhand sprinkler heads remote from the fire may aged or collapsed, and so that the dampers thembecome heated to the operating temperature and selves are not damaged. 7 open to discharge the extinguishing fluid where Another object of the invention is to detect it will fail to extinguish the fire. Thermostatic fires occurring in the combustible oil' or other and certain other automatic fire protection systype air filters that are used in air conditioning tems also fail to operate owing to the fact that Sy ems, a d to ol s and d mpers upon the cold air circulating at high velocity prevents such detection, and in cases where automatic the usual rise in temperature due to fire condiextinguishers are provided to eontrolfilter fires, tions and therefore prevents operation of the particularly Wh re t ese extinguisherszare of the fire protection systems. gaseous (CO2) or dry Powder types, to so control Air conditioning systems also cause extensive the air conditioning y m that h x guishdamage by circulating smoke from the fire, there- 18' s or powder will be confined to an autoby causing extensive smoke damage throughout tic y is sectio .llmited in ,S. the ventilated enclosure even though the fire it- 5 o n the filter. s P itt ng-the use of self is confined to a small portion thereof. Air ess Of the extinguishing medium than would, conditioning systems may also under certain con Otherwise be r quired, and so t at thee t guishditions draw in smoke from an outside fire and 18 e i m. whi h may be harmful in nature cause extensive smoke damagewithin the ventiei h r to humans to in pr r y Such as lated enclosure even though the fire does not delicate fabrics, will not be introduced into the occur therein. Furthermore, the duct system of S pp y duct 0 an air o i o ing system. a ventilating or air conditioning system will Another object of the invention is to provide spread fire directly to various parts of the builda mok det r. which also functions as a haze ing unless some extinguishing means is located detector, which will detect any colored or partly within the ducts. Ducts with combustible linopaque gas other than smoke which may be inings, or containing accumulations of combustible lint and small scraps of involved in fires.

The principal object of this invention is to propaper may also become troduced into an air conditioning system. Such a gas would be introduced upon accidental leakage of certain refrigerating gases from the cooling coils into the air stream.

Another object of the invention is to provide a means of disabling an air conditioning system which can be controlled from a conventional waterfiow detector or a sprinkler system within an enclosure, so that if a sprinkler should operate, even though that sprinkler may not be the proper one to control a fire, it would disable the air conditioning system, thus causing the circulation of air to cease, and permitting the proper sprinkler to come into action with a minimum of delay.

Still another object of this invention is to provide a means for disabling an air conditioning system which can be controlled by the conventional manual or automatic fire alarm system which is adapted to supervise fire conditions within an enclosure, automatic fire alarms of the pneumatic, rate-of-rise type known as Aero-tube systems being particularly applicable because they take advantage of the dispersion of the slightly heated air from a fire, the dispersed air being spread along more and more of the protective tubing as the air spreads, this accumulating partial pressures in the Aero-tube system, so that it functions in spite of the high air velocities.

Further objects and advantages will appear from consideration of the following description of the drawings wherein:

- Fig. 1 is a diagrammatic view of an air conditioning system and a fire protection system for controlling the same.

Fig. 2 is a detailed view of a damper and an electromagnetic release for opening and closing the damper.

Fig. 3 is a detailed view of a pneumatic operating unit for controlling dampers.

Fig. 4 is a circuit diagram showing the relation between a. manual fire alarm system, a smoke detector and the control circuit for operating dampers in the system shown in Fig. 1.

Fig. 5 is a diagrammatic view of an alternative arrangement of the smoke detecting unit with respect to a duct in the air conditioning system.

Fig. 6 is a detailed view of the pneumatic control shown in Fig. 3 and the electromagnetic valving arrangement for operating the control unit.

Fig. 1 of the drawings shows a fire protecting system for use in air conditioning systems wherein a smoke detecting unit I is arranged with respect. to the main supply duct 3 for detecting the passage of smoke and controlling the dampers in the duct system to prevent the circulation of smoke within the air conditioned enclosure. The air conditioning system comprises a return air duct 5 which feeds the returned air to a filter unit I, and to a conditioning unit containing cooling coils 8 and heating coils 9, from which the air is impelled by the main supply fan l0 through the main supply duct 3 to the feed ducts of the system, not shown. Air may be recirculated without filtering or further conditioning through the by-pass II to the fan In depending upon the position of the automatic regulating damper l5. Fresh air enters the system through the fresh air intake l6 and passes through the sectionalized damper ll to the filters and conditioning coils. Damper ll may be automatically controlled in accordance with sea damper 22 is situated at the fire wall 26 for the purpose of controlling the air flow through return air duct 5. The automatic regulating dampers I1, 21 and 28 are also controlled in the event of a fire to aid in stopping the circulation of air through the system. These dampers are normally controlled from a pneumatic pipe system which will be described later.

The preferred smoke detecting arrangement is of the light-sensitive type and comprises a lightsensitive cell I, a mirror 2 and light source 4, which combination directs a light beam across the path of air fiow in the main supply duct whereby passage of smoke through said duct will decrease the amount of light passing to the lightsensitive cell and cause said cell to decrease its output. The celloutput is fed into a control unit, shown in detail in Fig. 4, which operates the relay 30 and energizes an electric circuit l2 from a source of potential. The fire dampers 2i'i,

2| and 22 are controlled by electromagnetic release mechanisms 3l, 32 and 33, respectively, while the automatic regulating dampers I1, 21 and 28 are controlled from the pneumatic control system by means of the

electromagnetic valves

34, 35 and 36, respectively, which are connected to the electrical circuit l2. The

fan motors

31 and 38 .are also under the control of the smoke detector circuit through their

starting boxes

39 and 40, respectively, so that during the passage of smoke through the main supply duct the

fan motors

31 and 38 are stopped to prevent the circulation of air or smoke through the duct system. Fan 29 driven by motor 38 serves to exhaust air from the system as conditions require. The pneumatic control system comprises a storage pressure tank 4| which maintains a given pressure in the pipe system, the branches of which extend to pneumatic damper motors 42 which operate the automatic regulating dampers. Temperature and humidity sensitive apparatus, not shown, automatically controls the regulating dampers l5, I1, 21 and 28 through the same pneumatic pipe system, thereby maintaining the desired temperature and humidity conditions.

Fig. 2 shows the details of the electromagnetic release which is used for closing the dampers 20, 2| and 22 in the event a fire occurs. When smoke passes through the main supply duct 3, the smoke detector equipment operates to energize the solenoid 41, plunger 48, and the link member 45. The link 45 drops to release the connection 44 and the damper 22. Damper 22 closes under the restraint of the dashpot 43 which acts as a timing element for preventing sudden closure of the-damper and the consequent evacuation of the duct connected to the main supply fan. Thus it is possible to close the dampers 20, 2| and 22 in any desired order and over any desired period of time after the smoke detector operates. The link 44 includes a fusible element 46 inside the duct which serves the purpose of detecting dangerous rises in temperature which might not be detected by the smoke detector. If a smokeless fire condition arises. the fusible elements such as 8 become melted at certain given temperatures and allow the dampers to close, thus preventing the spread of smoke or fire through the duct system. The dampers may be restored to their normal condition by manually restoring the link member 45 and the connection 44 to their normal positions. It is evident that the release mechanism operates in the same manner in response to actuation of all the equipment shown in Fig. 4.

Fig. 3 is a diagrammatic showing of the pneumatic damper motor which comprises a diaphragm member 58 adapted to be operated from a. pneumatic pipe line by an increase or decrease of pressure within said line. When the pressure is released, the movement of the diaphragm 58 is transmitted to the damper through the arm under the influence of spring 52. Such pneumatic damper operating devices are shown in Fig. l in connection with the automatic regulating dampers I1, 21 'and 28.

Fig. 4 shows, in detail, the electrical control circuit shown in Fig. 1 for controlling the fire protection dampers and the automatic regulating dampers comprising a manual fire alarm system, an automatic fire alarm system, the light-sensitive smoke detecting system and also contacts operated by water fiow in an automatic sprinkler system. This circuit acts as 'a' fire protective system and is so claimed in the appended claims. The manual fire alarm system comprises manually operated boxes, each containing a set of contacts such as those indicated by 53, the contacts being connected in a series circuit. This circuit is normally closed and maintains the relay 30, also shown in Fig. 1, normally energized. Relay 30 controls the transmitting relay 58, which in turn operates the central oflice transmitter 59. Relay 30, through its contacts 56, controls energization vof the motor and damper operating circuit l2 shown in Fig. 1. Light-sensitive cell I also controls relay 80 through its associated relays 62 and 64, whereby a smoke condition will alsocause closure of the dampers and the stopping of the fan motors in the air conditioning system shown in Fig. 1 The normally closed contacts 51 which are adapted to be operated by a pressure supervisory motor 68 shown in Fig. 1 control relay 69, which in turn controls a transmitter H! for transmitting trouble signals to the central oflice for the purpose of notifying the central oflice operator of an abnormal pressure condition within the pneumatic valve system shown in Fig. 1. Thus the pneumatic system is under constant supervision.

It is also necessary to control the air conditioning system by means of water-flow detectors and automatic fire detecting systems so that in the event of a sprinkler head operating or in the event of fire within the enclosure, the air conditioning system will be disabled. It is further necessary to detect the fire conditions exist ing within the duct system and within'the air filters, which are located within the duct system.

In order to conveniently control the air conditioning system from the above mentioned protective devices, additional contacts are provided in the manual fire alarm system. Contact 55 is adapted to be operated by a water-flow detector 80 within the sprinkler system while contacts 54 are adapted to be operated thermostatically by heat responsive elements located within the duct system within the oil filter unit 1 or by an automatic fire detecting system in the tioning system itself, relay 80 will be deenergizedtocause disablement of the air conditioning system or complete stoppage of the flow 01 air.

The operation of the electrical circuit described above may start either by manual operation of one or more or the contacts 58 in the manual fire alarm system or from the smoke detector locatedwithin the duct system. It one of the

contacts

58, 54 or 55 are opened, relay 80 becomes deenergized thereby closing

contacts

55 and 51. Contacts 55 close to energize circuit l2 'which operates the electromagnetic releases 8|,

82 and 83 therebyclosing the fire dampers. Valves 34, and 85 are also operated to close the automatic regulating dampers ll, 21 and 28.

Closure of contact 51 energizes relay 58 to start the central oflice transmitter 59 which transmits a fire alarm. The localalarm 6| is also energized'at this time by closure 01' contacts BI] 01 relay 58.

When smoke circulates through the duct system, light-sensitive cell i energizes the relay" which closes its contact 63 to energize relay 8|. Relay 6| closes contacts 55 which energizes the transmitter relay 58 and the alarm. so that a fire alarm is also transmitted when a smoke condition arises. Light-sensitive cell I also causes the contact 66 to open, which is in the manual fire alarm circuit, and operates relay 38 as above described in connection with manual firealarm operation.

, Fig. 5 shows an alternative arrangement of the smoke detecting apparatus with respect to the main supply duct 3. In air conditioning systems or ventilating systems with extremely high air velocities, it is found that the smoke particles become so well difiused in the circulating air that smoke detection is very diflicult and therefore it is sometimes necessary to use a long light beam which may be intercepted'by a comparatively long air path whereby a greater amount of air and smoke can traverse the protectiive light beam. To accomplish this result, the lightsensitive cell I and the source 4 are supported .in angular relation to duct 3 whereby. the light emitted by sourced traverses an angular path with respect to the duct 3.

- The air conditioning system employs large heavy supply fans for impelling air through the system, and the fans have such great momentum that they continue to rotate for an appreciable period after the motor is cut off by the fire protection circuit. The result of this large momentum is that sudden closure of all dampers closure of the pneumatically operated dampers.

with respect to operation of.the electrical control circuit. Electromagnetic releases may be similarly delayed byinterposing time delay elements in their circuits. The electromagnetic valve 12 is operated from the control circuit l2,

shown in Figs. 1 and 4, at the time that the fan motors are shut down. Valve 12 admits air from the supply pipe 13 to pipe 78. Increase of pressure in pipe 14 would normally operate the conthe gate valve I5 is provided. Gate valve II alows a slow increase of pressure within control unit 16 to thereby delay its operation for a period of several seconds. Another means for obtaining the same result is the expansion tank 11, which may be used either separately or in combination with gate valve 15. The expansion tank ll operates to cause the pressure within the contro1 unit 16 to increase slowly over a period of several seconds thereby delaying operation of the dampers.

From the above description of the protection system for air conditioning systems, it is evident that either an occurrence of smoke within the duct system or operation of one or more contacts in the fire alarm system will energize the electrical control circuit [2, which in turn operates the electromagnetic release devices 3i, 32 and 33 to control the fire dampers 20, 2| and 22, respectively. Energization of the circuit l2 also operates the

pneumatic valves

34, 35 and 36 to in turn operate the control units 42 for closing the automatic regulating dampers i1, 21 and 28. The

fan motors

31 and 38 are also stopped when the circuit [2 energizes the stopping

devices

39 and 40. The result of operation of the fire control and fire protection system is to completely disable the air conditioning system, thereby stopping'circulation of air and smoke or the spread of fire through the duct system itself. However, the dashpots, such as 43 in Fig, 2, and the gate valves, such as 15 in Fig. 6, are so adjusted that the dampers close in the proper sequence and at such a speed that collapse or bursting of ducts is avoided.

It is evident from the above description that applicants provide a protection system for air,

conditioning systems which effectively disables the air conditioning systemto prevent the cir-' culation of smoke through a building or other enclosure and also prevent the circulation of other gases such as refrigerants which might be dangerous to humans or destructive of materials stored within the enclosure. The protective system further provides a means for disabling the air conditioning system for the purpose of preventing circulation of air at high velocities which would prevent the proper and eflicient operation of sprinkler systems. If the air conditioning system were to continue high velocity circulation of air after a fire condition arose, the sprinkler system would be completely disabled and would allow spread of fire.

This invention also provides a means whereby the manual and automatic fire alarm systems which are ordinarily installed in all buildings of large size can control the air conditioning system to disable it upon the occurrence of fire conditions. The invention further-causes duct fires to be confined to the: particular part of a duct system in which they may have started. The fire dampers and the automatic regulating dampers under the control of the fire protective system will always confine the fire to the duct system. If extinguishing material or substances are discharged within the duct system the fire dampers also prevent the circulating fans from circulating the fluids or gases used for extinguishing purposes.

It is not intended that the term air conditioning system shall be limited to mean a system for controlling the temperature, humidity and motion of air as it obviously may refer to any system which controls either the temperature, humidity or motion, or all three conditions of the air within an enclosure.

It will be obvious to those skilletf'in the art that various modifications are possible within the scope of the appended claim and we desire that this invention shall only be limited by the prior art and the appended claims.

We claim:

1. In an air conditioning system, an enclosure to be supplied with conditioned air, means for conditioning air, a duct system communicating with said enclosure for supplying air to and from said conditioning means, a fan for impelling air through said conditioning means and duct system to said enclosure, a plurality of dampers in said duct system for controlling the fiow of air therethrough and a smoke detecting apparatus in the duct system to detect the passage of smoke through said duct system and mean operatively connected to said smoke detecting apparatus for electrically closing said dampers during fire conditions Within said enclosure or said air conditioning system.

2. In an air conditioning system, an enclosure to be supplied with conditioned air, means for conditioning air, a duct system communicating with said enclosure for distributing air from said conditioning means to said enclosure, means for impelling an air stream through said duct system and smoke detecting means for scanning the air stream to detect the passage of smoke through said duct system and means operatively connected to said smoke detecting means for stopping circulation of air through the duct system.

3. In an air conditioning system, an enclosure to be supplied with conditioned air, means for conditioning air, a duct system arranged to distribute air from said conditioning means to said enclosure, a supply fan for impell'ing air through said duct system, fire detecting means including a smoke detector arranged to be afiected directly by the presence of smoke in the air impelled by the fan through said duct system and means operatively connected to said fire detecting means for controlling the fiow of air through the duct system.

4. In combination, an enclosure, an air conditioning system comprising means for conditioning air, a duct system communicating with said enclosure for supplying air from said air conditioning system to said enclosure, a supply fan for impelling air through said duct system and a plurality of dampers in said duct system for controlling the fiow of air therethrough, a fire protection system including smoke detecting apparatus for detecting the passage of smoke in said duct system and a sprinkler system in said enclosure for extinguishing fires and means operatively connected to the fire protection system for disabling said air conditioning system when either said smoke detecting apparatus or sprinkler operates whereby circulation of air and smoke is stopped and efiective operation of the tecting means for disabling said air conditioning system.

6. In combination, an enclosure, an air conditioning system comprising means for condi fire protection system for closing all dampers and stopping the fan in said air conditioning system during fire conditions and means for controlling the speed of closure of said dampers to thereby prevent abnormal pressure and collapse of the ducts.

'7. In combination, an enclosure, an air conditioning system comprising means for conditionin'g air, a duct system for supplying air from said means to said enclosure, a main supply fan for impelling air through said duct system, a plurality of dampers for controlling the flow of air through said duct system, a fire protection system within said enclosure for protecting it against fire, means operatively connected to be operated by said fire protection system for closing all dampers and stoppin the fan in said air conditioning system during fire conditions and means for delaying the closure or said dampers to allow said fan to stop its rotation and thereby prevent collapse oi! ducts.

ling the speed of closure of said dampers while said fan stops its rotation to thereby prevent the abnormal pressure and'collapse of the ducts.

9. In combination, an enclosure, an air conditioning system therein comprising means for conditioning air, a duct system for supplying air to said enclosure from said means, a fan for impelling air through said duct system, a-plurality of dampers for controlling the flow of air through said duct system, smoke detector apparatus for detecting smoke in the air circulated by the fan, means responsive to said smoke detector apparatus for closing all dampers and stopping the fan in said air conditioning system and means for delaying the closure of said dampers While rotation of said fan is stopping to thereby prevent abnormal pressure and the collapse of ducts.

PAUL M. FARMER.

FRANCIS C. EVANS.

RICHARD F. SPAMER.