US2935135A

US2935135A - Smoke detecting and fire extinguishing system

Info

Publication number: US2935135A
Application number: US783927A
Authority: US
Inventors: Jr Harry C Grant
Original assignee: Specialties Development Corp
Current assignee: Specialties Development Corp
Priority date: 1958-12-30
Filing date: 1958-12-30
Publication date: 1960-05-03
Anticipated expiration: 1977-05-03

Description

y 1960 H. c. GRANT, JR 2, 35,135

SMOKE DETECTING AND FIRE EXTINGUISHING SYSTEM Filed Dec. 30, 1958 2 Sheets-Sheet 1 VIII/l 'IIIIII4 H INVENTOR u BY 3 g ATTORNEY Ma a, 1960 H. GRANT, JR

SMOKE DETECTING AND FIRE EXTINGUISHING SYSTEM 2 Sheets-Sheet 2 l n H I H I. l l l l l l H HOLD N 1 Filed Dec. 30, 1958 INVENTOR H (lgmmfl'r. BY Wm M ATTORNEY 7 SMOKE DETECTING sAND FIRE EXTINGUISHING YSTEM Harry C. Grant, Jr., Ridgewood, NJ., assignor to Specialties Development Corporation, Belleville, N.J., a corporation of New Jersey Application December 30, 19 58, Serial No. 783,927

8 Claims. cl. 169- The present invention relates to smoke detecting and fire extinguishing systems, and, more particularly, to such systems for detecting smoke and extinguishing fire in an enclosure which is periodically ventilated, for example, a cargo hold of a ship.

For many years, the cargo holds of ships have been protected by systems for detecting smoke caused by the start of a fire in the holds and for introducing a fire extinguishing medium such as carbon dioxide into the holds to smother the fire. Generally, such a system comprises a smoke detector located in the pilot house having a plurality of units corresponding to the number of holds or enclosures to be protected for indicating the location of the origin of the smoke, each unit having an inlet and the detector having an outlet common to all of the inlets; a conduit running fore and aft through the middle of each hold near the ceiling; one or more accumulators in the conduit into which air in the hold is drawn; a pipe leading from each conduit to an inlet of the detector; and an exhaust fan connected to the outlet of the detector for drawing air samples taken from the hold and through the indicating units. rality of receptacles containing fire extinguishing medium such as carbon dioxide which receptacles are located below deck in the vicinity of the pipes asthey come together before running up to the pilot house, a manifold for the receptacles into which carbon dioxide is discharged, discharge pipes each connected to one of the air sampling pipes and to the manifold, valving for the discharge pipes to determine to'which hold the carbon dioxide is to be directed, and anormally open valve in each air sampling pipe which is closed during the discharge of carbon dioxide to prevent the carbon dioxide from flowing to the smoke detector and thereby direct the carbon dioxide to the conduit for discharge through the accumulators. v

Also, for many years, it has been customary to connect a cowl ventilator facing fore or windward to introduce air into the holds and to connect another cowl ventilator facing aft or leeward to withdraw air from the holds to thereby provide a ventilating system.

More recently, cargo holds have been equipped with Ventilating systems for periodically conditioning the air in the holds to remove odors or excessive moisture therefrom or to change the temperature of the air. Generally, such a system comprises an apertured duct running fore and aft'at each side of the hold so that the air sampling conduit is located intermediate the ducts, means for introducing ventilating air into One ofthe ducts and into the hold, and means for withdrawing ventilating air from the other of the ducts and from the hold. In such a system, a motor driven blower was connected to the duct for introducing the air'and/or a motor driven exhaust fan was connected to the duct for withdrawing the air.

The use of both a smoke detecting and fire extinguishing system and a ventilating system of either type. described above has created a eonsiderable problem because the ventilating air in passing'through the hold disrupts the The system further comprises a plu-' Patented May 3, 1960 proper functioning of the air sampling conduit to the extent that any smoke originating in the hold downstream of the air sampling conduit and near the fore and aft walls of the hold is carried away by the ventilating air and cannot reach the air sampling conduit. Consequently, more than half of the hold is unprotected by the smoke detecting system and small fires can start and be fanned by the ventilating air to fires of a considerable magnitude before being otherwise detected. This is a hazard which cannot be tolerated by safety and fire pre venting practices.

Accordingly, an object of the present invention is to provide a smoke detecting system which functions properly. and is unaffected by a ventilating system in the same cargo hold or other enclosure.

Another object is to provide such a smoke detecting system which is conditioned automatically while the ventilating system is, or is not, functioning.

Another object is to provide such a smoke detecting system which can be combined with a fire detecting system.

A further object is to provide such a system in a simple, practical and economical manner.

Other and further objects of the invention will be obvious upon an understanding of the illustrative embodiment about to be described, or will be indicated in the appended claims, and various advantages not referred to herein will occur to one skilled in the art upon employment of the invention in practice.

In accordance with the present invention, the foregoing objects are accomplished by providing a smoke detecting system wherein sampling air is withdrawn from the enclosure by the conduit having therein the accumulators or the like when the ventilating system is not in operation, and wherein sampling air is withdrawn from the duct through which air withdrawn or removed from the enclosure flows when the ventilating system is in operation, provision being made to switch over the sampling operations as the ventilating system goes on or off.

A preferred embodiment of the invention has been chosen for purposes of illustration and description, and is shown in the accompanying drawings, forming a part of the specification, wherein:

, Fig. l is a schematic plan view of a ships cargo hold provided with ventilation and equipped with a smoke detecting and fire extinguishing system in accordance with the present invention. g

Fig. 2 is an enlarged fragmentary sectional schematic view taken along the line 2-2 on Fig. l. Fig. 3 is an enlarged fragmentary sectional schematic view taken along the line 3--3 on Fig. 1.

Fig. 4 is a sectional view of one form of control valve for the system.

Fig. 5 is a wiring diagram of the circuit for energizing the motor of a blower and/or an exhaust fan including Referring to Fig. 1 of the drawings in detail, there is shown a ships cargo hold providing an enclosure 10, which is ventilated and is protected by a smoke detecting and fire extinguishing system.

Ventilation is provided by a perforated duct 11 at one side of the enclosure for introducing fresh air into the enclosure andby a second perforated duct 12 at the opposite side of the enclosure for withdrawing air from the enclosure. Each duct has one or more rows of slits or perforations 14 which preferably face the middle of the enclosure. Fresh air is supplied to the duct 11 by a pipe 15 which is connected thereto and extends upwardly to above deck and has a shield 16 at its upper end (Fig. 2) for preventing waves and spray from entering the same. A motor driven fan or blower 17 is positioned in the pipe 15 at a suitable location. The air supplied to the I ensures enclosure is. removed from the duct 22 by a pipe 18 deck and, like the pipe 15, has a shield 16 at its upper end (Fig. 3). A motor driven exhaust fan 19 is posi-' tioned in the pipe, 1 8; at a. suitable location.

- Referringagain to Fig. 1, there also is shown a smoke detecting system which is arranged in a conventional manner and generally comprises a smoke detector 20-having; a plurality of units 21, four being shown, corresponding to the number of enclosures It to be protected for indicating the. enclosure in which smoke is detected, each unit 21 having and inlet 22 and the detector 20 having an outlet 24 common to all of the inlets; a conduit 25 preferably' running fore and aft through the middle of the enclosure near the deck above; one or more accumulators 26 in. the conduit 25 into whiclrair from the enclosure can enter, two accumulators being shown which may be of the type shown in United States Patent'Reissue No. 22,047; a pipe including a section 27 connected to conduit 25 and a section 28 leading to the inlet 22 0f the unit 21 associated with the enclosure; and an exhaust fan 29 connected to the outlet 24 of the smoke detector for withdrawing air samples from the enclosure and through the smoke detector.

There is further shown a fire extinguishing system 4 which is also arranged in aconventional manner and generally comprises a supply of liquefied carbon dioxide 39, such as a bank of cylinders; a; manifoldii connected to the bank of cylinders having a plurality of valve controlled outlets 32 corresponding to the number of enclosures .10; a discharge pipe 34 for connecting the corresponding outlet 32 and pipe section 28; and a valve 35 in the pipe section 28 having an inlet to which the dis charge pipe 34 is connected.

The valve 35 is constructed and arranged to normally pennit sampling air to be withdrawn from-the enclosure and, upon detection of smoke or tire, to be positioned to shut off flow communication between the smoke detector and the enclosure and to establish how communication between the discharge pipe 34and the pipe section so that carbon dioxide can be introduced 'into the enclosure to extinguish the fire. If desired, the manifold 31, the valved controlled outlets 32, the discharge pipe section and the valves. 35 may be arranged in a valve. assembly such as shown in United States Patent No. 2,661,765.

-While the ventilating system has been illustrated and described with reference to using both a blower and an exhaust fan, it will be apparent that either only a blower and an air outlet oronly an exhaust fan and an air inlet could be used as the means for introducing air into the enclosure and for removing air therefrom.

' The. ventilating system and' the smoke detecting system,

as so far described, each would function in its intended manner, but these systems cannot be used together without causing the smoke detector to be rendered ineffective due to. the difficulties already described. These difficulties are .overcome by providing an arrangement for sampling the air removed from the enclosure and passing through the ventilating duct 12 while the ventilating system is in operation.

As shown in Fig. 1, such an arrangement comprises a direction valve 36 having an inlet 37 in fluid flow communication with the enclosure through the pipe section 27, the conduit 25 and the accumulators 26; an inlet 38 connected by pipe 39.to the duct-12; an outlet or port &0. connected to the pipe section 28; and a movable flow control member, described hereinafter, for establishing fluid flow communication between the inlet 37 and the outlet 40, when the ventilating system is not operating,

and for establishing fiuid flow communication between the inlet 38 and the outlet 49, when the ventilating system is operating.

The pipe 39 preferably is connected to the duct 12; under the pipe 18 (Fig. 3), and. has a downwardly facing inlet 33 at'va level above the perforations 14 in the duct,

for entraining smoke laden air drawn into the duct at any point along the length thereof. In practice, the suction in the pipe 39 created by the exhaust fan 29 is greater than the suction or draft in the pipe 18, whereby sufficient sampling air will be withdrawn from the duct 12 to assure the detection of smoke therein.

in order to prevent the loss of fire extinguishing medium through the pipe 39, the duct 12 and the pipe 13 to the atmosphere while the inlet 33 and the outlet 40 are connected during operation of the ventilating system, a normally open floating check valve 41 may be connected in the pipe section 28near the outlet 46 which is adapted to close when fire extinguishing medium is discharged into the pipe section 28. The blocked fire extinguishing medium may be by-passed through a normally closed poppet valve 42 connected to the pipe section just downstream of the check valve 41 in the direction of how of sampling air and may be discharged directly into the enclosure from the outlet of the poppet valve or may be discharged into the enclosure through the accumulators 26 by connecting the outlet of the poppet valve by a pipe 44 to the accumulator conduit 25.

In the event the ventilating system includes electric motor driven fans and additional wiring to each enclosure can be tolerated, the direction valve 36 could be under the control of a solenoid arranged in the motor energizing circuit to position its flow controlling member to sample the air in the duct 12 when the motors are energized and to sample air in the enclosure when the motors are tie-energized.

v However, on board ship where wiring is desired to be kept at a minimum, the direction valve 36 may be controlled in response to the flow of air from the pipe 15 into the duct 11 byconnecting one end of a flow sensing i pipe 45 m the duct 12 having an inlet 4-6 directly under will not interfere to suck air at maximum negative pressure therethrough and by connecting the other end of the sensing pipe to a control device for the valve 36 in the manner about to be described.

In Fig. 4:, a preferred direction valve 36 is shown which is responsive to a suction or negative pressure operated device. 47. The valve comprises a body 48 in which are formed the

inlets

37 and 38 and the outlet 40, a valve seat 49 between the inlet 37' and the outlet 40, a valve seat 50 between the inlet 38 and the outletdil, a valve member 51 for the seat 49, a valve member 52. for the seat 50, and a slidably mounted rod 54 on which the valve members are mounted having one end 55 extending outwardly of the valve body.

I The valve member 51 has a larger efi'ective area than the valve member 52, whereby the pressure of the fire extinguishing medium, when discharged into the port 4d, will ovecome the force exerted by the negative pressure of the device 47' and will shift the valve member 51 towards the left as viewed to shut ofi communication between. the port 40 and the inlet 33. This prevents the loss of fire extinguishing medium byway of the duct 12 in event the fire extinguishing medium was released prematurely, that is, before the exhaust fan was stopped.

' The valve 36; when constructed as just described eliminates'the need for the, valves. 41 and 42.

The pressure responsive device 47 comprises a casing 56, a pressure sensitive element 57 movably mounted in the casingandsecured to the end 55 of the rod and dividing the casinginto' chamber sections 53 and 5?, a vent 60 for the, chamber section 58 through which the rod end 55 extends, an. opening 61 for the chamber section 59 to which the, sensing pipe is connected, and a light spring 62 for urging the valve member 51 off its seat and the valve member 52 on its seat.

, The devicje.,47 is shown in the position it assumes when the. ventilating. system is. in operation, that is, with the exhaust, fan 19 creatingsuction. to. drawthe. element 57 and the rod 54 to the right, as viewed, in opposition to the spr ng, whereby flow communication is established between the exhaust duct 12 and the smoke detecting system. When the exhaust fan is shut down, the pressure in the chamber section 59 goes to atmospheric and the spring 62 is effective to shift the valve members to establish communication between the enclosure and the smoke detecting system.

In normal practice, the motors for the blower 17 and the exhaust fan 19, if operating at the time smoke is detected, should be shut down before fire extinguishing medium is discharged into the enclosure, because otherwise the fire extinguishing medium would be withdrawn by the ventilating system through the apertures 14 in the 1 exhaust duct 12 even if the valve member 52 is seated.

Because, in the excitement of a fire being detected, an established routine of operations may be performed improperly, particularly by inexperienced operators, the present invention provides an arrangement for automatic shut down of the motors in response to the-release of the fire extinguishing medium.

In Fig. 5, one way of accomplishing this is shown. For example, the motor energizing circuit may comprise a motor M for the blower and/or exhaust fan, a' source of power P, a master or control switch 64, a normally closed safetyswitch 65 connected in series with the switch 64, and a pressure operated device 66 for opening the switch 65. i I

The device 66 comprises a cylinder 67, a piston 68 in the cylinder, a rod 63 carried by the piston and adapted to be extended outwardly of the cylinder to engage the switch 65, and open the same, a spring 69 for retracting the piston rod, and a pipe 70 having one end connected to. the cylinder in piston driving relation and having its other end connected to the pipe section 28 (Fig. l). The pipe 70 can pass through the ducts 11 and 12 and the

pipes

15 and 18 to the devices 66.

Thus, when the motor is energized with the

switches

64 and 65 closed as shown and fire extinguishing medium is releasedprernaturely, the device 66 is effective to open the switch 65 and thereby de-energize'the motor.

"From the foregoing description, it will be seen that the present invention provides a novel and useful arrangement which enables enclosures to have ventilation and at the same time be protected by a smoke detecting and fire extinguishing system. The invention can be embodied in newly constructed enclosures, enables enclosures protected by a smoke detecting and fire extinguishing system to now be equipped with ventilation, and enables ventilated enclosures to now be equipped with a smoke detecting and fire extinguishing system;

- It will also be understood that the present invention can be utilized in ventilated enclosures where only smoke detection is required and the'fire is extinguished by other means than a total flooding carbon dioxide fire extinguishing system as described herein.

,As various changes may be made in the form, con! struction and arrangement of the parts herein, without departing from the spirit and scope of the invention and without sacrificing any of its advantages, it is to be understoodithat all matter herein is to be interpreted as illustrativerandnot-in any limiting sense.

I claim:

= .1. Ina smoke detecting system for an enclosure, the combination of means for introducing ventilating air into the enclosure, means for withdrawing air from the enclosure, conduit means'for withdrawing sampling air from the enclosure located intermediate said ventilating air introducing and withdrawing means, conduit means for withdrawing sampling air from saidventilating air withdrawingrrieanasmoke detecting means through which sampling air is passed, valve means having a pair of inlets each'in fluidflow connection with one of said conduit means and having an outlet, and means for establishing a fluid flow connection between said outlet and said 6 smoke detecting means, said valve means including a flow control member for selectively establishing fluid flow coin munication between one of said inlets and said outlet and for preventingfluid flow communication between said other inlet and said outlet, said control member being normally positioned to establish communication between said outlet and said inlet connected to said enclosure air sampling conduit means and being operable during the flow of ventilating air to establish communication between said outlet and said inlet connected to said ventilating air sampling conduit means.

2. In a smoke detecting system for an enclosure, the combination of means for introducing ventilating air into the enclosure, means for withdrawing air from the enclosure, conduit means for withdrawing sampling air from the enclosure located intermediate said ventilating air introducing and withdrawing means, conduit means for withdrawing sampling air from said ventilating air withdrawing means, smoke detecting means through which sampling air is passed, valve means having a pair of inlets each in fluid flow connection with one of said conduit means and having an outlet pipe means for establishing a fluid flow connection between said outlet and said smoke detecting means, said valve means including flow control means for selectively establishing fluid flow communication between one of said inlets and said outlet and for preventing fluid flow communication between said other inlet and said outlet, means for normally positioning said control means to establish communication between said outlet and said inlet connected to said enclosure air sampling conduit means, and means operable by '.he flow of ventilating air for positioning said control means to establish communication between said outlet and said inlet connected to said ventilating air sampling conduit means. I

3; In a smoke detecting system for an enclosure, the combination of means for introducing ventilating air into the enclosure, means for withdrawing air from the enclosure-,=conduit means for withdrawing sampling air from the enclosure located intermediate said ventilating air introducing and withdrawing means, conduit means for withdrawing sampling air from said ventilating air withdrawing means, smoke detecting means through which sampling air is passed, valve means having a pair of inlets each in fluid flow. connection with one of said conduit means and having an outlet, means for establishing a fluid flow connection between said outlet and said smoke detecting means, said valve means including 'a flow control member for selectively establishing fluid flow communication between one of said inlets and said outlet and for preventing fluid flow communication between said other inlet and said outlet, a spring for normally positioning said control member to establish communication between said outlet and said inlet connected to said enclosure air sampling conduit means, and a pressure sensitive element operable during the flow of ventilating air to position said control member to establish communication between said outlet and said inlet connected to said ventilating air sampling conduit means.

4.- Ina smoke detecting and fire extinguishing system for an enclosure, the combination of means for introducing ventilating air into the enclosure, means for withdrawing air from the enclosure, conduit means for withdrawing sampling air from the enclosure located intermediate said ventilating air introducing and withdrawing means, conduitmeans for withdrawing sampling air from said ventilating air withdrawing means, smoke detecting means through which sampling air is passed, valve means 7 having a pair of inlets each in fluid flow connection with one of. said conduit means and having an outlet, means for establishing a fluid flow connection between said outlet and saidsmoke detecting means, said valve means, including a flow control'member for selectively estabmunication between said other inlet and said outlet, at source of fire extinguishing medium under pressure ineluding means connected for discharging the medium into the enclosure, said control member beingnormally positioned to establish communication between said outlet and said inlet connected to said enclosure air sampling conduit means, and being operable during the flow of ventilating air to establish communication between said outlet and said inlet connected to said ventilating air sampling conduit means, and means operable during the discharge of fire extinguishing medium in response to the pressure thereof to prevent entry of the medium into the inlet connected to said ventilating air sampling conduit means.

5. in a smoke detecting and fire extinguishing system for an enclosure, the combination of means for introducing ventilating air into the enclosure, means for withdrawing air from the enclosure, at least one of said means including a motor driven fan, conduit means for withdrawing sampling air from the enclosure located intermediate said ventilating air introducing and Withdrawing means, conduitmeans for withdrawing sampling air from said ventilating air withdrawing means, smoke detecting means through which sampling air is passed, valve means having a pair of inlets each in fluid flow connection.

with one of said conduit means and having an outlet, means for establishing a fluid flow connectionbetween said outlet and said smoke detecting means, said valve means including a flow control member for selectively establishing fluid flow communication between one of said inlets and said outlet and for preventing fluid flow communication between said other inlet and said outlet,

a source of fire extinguishing medium under pressure including means connected for discharging the medium into the enclosure, said control member being normally positioned to establish communication between said outlet and said inlet connected to said enclosure air sampling conduit means, means responsive to the flow of ventilating air to establish communication between said-outlet and said inlet connected to said ventilating air sampling conduit means, a normally closed pressure voperated? switch for said motor. driven fan, and a fluid flow connec-- tion between said switch and said fire extinguishing medium discharging means for opening said switch in response to the pressure of the medium upon discharge thereof.

6. In a smoke detecting and fire extinguishing systemfor an enclosure, the combination of means for introducing, ventilating air into the enclosure, means for withdrawing air from the enclosure, at least one of said means including a motor driven fan conduit means for withdrawing sampling air from the enclosure located intermediate said ventilating air introducing and withdrawing means, conduit means for withdrawing sampling air from said ventilating air withdrawing means, smoke detecting means through which sampling air is passed, valve means having a pair of inlets each in fluid flow connection withone of said conduit means and having an outlet,means for establishing a fluid flow connection between said outlet and said smoke detecting means, said valvemea'ns including aflow control member for selectively estab lishing fluid flow communication between one ofsaidinlets and said outlet and for preventing fluid flow com munication between said other inlet and said outlet, a source, of fire extinguishing medium under pressure iIi-' cludingrneans connected for discharging the medium intd the enclosure, said control member being normally po'si tioned to establish communication between said outlet" and said inlet connected to said enclosure air sampling conduit means, means responsive to the pressure of the fire extinguishing medium upon discharge thereof to shut ofi communication to said ventilating air sampling conduit means from said outlet and said enclosure, a normally closed pressure operated switch for said motor driven fan, and a fluid flow connection between said switch and said fire extinguishing medium discharging means for opening said switch in response to the pressure of the medium upon discharge thereof. 7

7, In a smoke detecting and fire extinguishing system for an enclosure, the combination of means for intro ducing air into the enclosure for ventilating the enclosure, means for withdrawing air from the enclosure, conduit means for withdrawing sampling air from the enclosure located intermediate said ventilating air introducing and withdrawing means, conduit means for withdrawing sam pling' air from said ventilating air withdrawing means, smo e detec ng mea s r h which mp air passed, valve means having a pair of inlets each in fluid flow connection with one of said conduit means and having an outlet, pipe means for-establishinga fluid flow connection between said outlet and said smoke detecting means, said valve means including flow control means for selectively establishing fluid flow communication be tween one of said inlets and said outlet and for preventing-fluid flow communication'between said other inlet and said outlet, sai d control means being normally positioned to establish communication between said outlet and said inlet connected to said enclosure air sampling conduit means and being operableduring the flow of ventilating air to establish communication between said outlet and said inlet connected to said ventilating air sampling conduit means, receptacle means for fire extinguishing medium under pressure, a pipe for establishing fluid flow communication between said receptacle,

duce fire extinguishing medium into said pipe means,-

outlet ineans in said pipe means between said last mentioned valve means and said outlet, said outlet means being infiuid' flow communication with the enclosure and including a normally closed valve for introducing fire extinguishing medium into the enclosure upon opening thereof, and a normally open valve between said outlet and' said outlet means for preventing flow of fireext'inguishing medium to said outlet upon closing thereof in response to the discharge of the medium.

8. In a ventilating and fire extinguishing system for an enclosure, the combination of means for introducing ventilating air into the enclosure, means for withdrawing air from the enclosure, at least one of said means in? eluding amotor driven fan, a source of fire extinguishingmedium under pressure including means connectedfor discharging the medium into .the enclosure, a normally closed switchand a control switch adapted to be closed t'o' effect operation of said motor driven fan, a pressureoper ated d'evice for opening said normally closed switch, and a fluid'fl'ow connected between said device and said fire extinguishing medium discharging means fdr efiecting operation of said device in response to the pressure of the medium, whereby, upon-discharge of the medium, operation or said motor driven fan ceases.

References Cited in the file of this patent UNITED STATES PATENTS B01116 Man-28, 1950