CA2010391A1 - Smoke - detector with back-up, delay monitoring circuitry - Google Patents

Abstract

ABSTRACT
A new improved combustion - smoke detection device including means for insuring that the device is operable with the optimum sensitivity that is substantially constant while initial power source has diminished. Another feature is that the present invention has a visible indication of a low-primary energy level, and an audible indication of a low-secondary level. Another primary feature of the present invention is that it is a re-chargeable system, and has the provisions of a means for testing the operation of the system with a manually actuated switch, and a means of a temporary signal producing delay or "silence"
circuit that is automatically de-activated after a predetermined time period. Another feature of the invention is that the circuitry for monitoring of energy level, and signal delay is of an energy efficient design extending the power source life.
Another feature of the present invention is that the preferred embodiment is mounted on a wall within reach of users for ease of control over its functions.

Description

Sl`lC~WE--DE'rEI-:Tt)r' WI'1'~1 L~C:~::UF'-DE'-LQ` Z01039 MONITOF.'INI:3 8IF.:C:UITr.:Y.
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r:a) Field -f Inventi-~n 1he presr-~nt inventif:n relates t~ c-11nb~1sti n--smck:e alarmc, anci m.~.re parti.ularly the present inventi--n relates t.-. pc.wer ba.k--~1p anri re-.-har~able systems, as well as anti-false alarm systems fcr use in alairms.
~:b:~ Des.riptic.n ..f Pri.-.r Art There are mar1y LiiFferent types .-.f sm{:.k:e dete._t..rs in use t..-..cJay.
The .-.-.nventi.-.rlal sm.-.ke ciete-t..:.r used in m.~.st h-.11~es are relatively s1r1all drevi.es that mc11nt n the eilinL~ and are trirlgered c1Ff by different dete-ti.:.n meth....cis. The smf:.1:e alarm has pr.-.ved -t-. be a~
:imp.-.rtant anri valuable warninc1 aL~Iincit fire a1~d haei ~n(:~1ubte(ily saved marly lives. E3~.1t there are many pr-.blems with them. 1: r e;.-.1mple, M.-.st sm..1:e dete_t-rs are m1-1urlte(i -.n the .-eilinr~ .-l.-.se t.-the kit.-hen; ..therc; are m.-.unted .-l.-.se t.. the bedr...ms f1 bathr..f-.mc, etc. Thus they may be set c.ff by ~_..-.1:inc~ s1n.1:e .r an aburlcdan.-e .~.f t..bba.-c. s~11..1:e. It i5 parti.~ularly anrl.-.yirlc1, anc:1 ...an ._ause a state .-.F panif:, It i'3 als-.. usually in an in~1::1nven:ierlt l~-ati.-.n t.-. rea...h with-ut a ladder ._.r .limbinc~ apparatuci! s.:. it i5 very hard t.. de activate, m..st pe.ple will pull .:~ut the hattery t.. sh1lt the 1.~nit .-.ff renrderi(ly tFle urlit in-.perative ~ntil sufh tin~e aCa the battery is repl.-~ ed anci the ~1nit tec~ted.
It is als~ a pr..blern wFlen the battery p.-.wer di1niniciheci, y.::.u miQht have n.:. indicati..r1 renL1erinr~ the s1n..1:e dete._t._.r ir1operativE.
lhese pr..blems may well render the alarm in~.perative tiurin4 a fire brea1.c.ut, and this may have rdevastatir1y effe.-t~ f:1n pe ples lives. WarninQ ~.--upa1lts ~.f the fire tianrter is ~1s~1ally the mai11 purpc.-3e. In pri-r art the Itn.wn systems r~enerally have a tw..
p.sit:i....n swit.-h ff.r fiilen~e and m..rnentary swit-h f.-.r reset, with this type ~f system the ._.peratc.r may n.-.t remember t._. de-a-tivate the silen--e swit.~h leavinr~ the system in--perable ~iurin~
a sit~aticn c.f a fire breal:._.ut.
~ a kQr.-.und Art In ..rder t-- appre.iate the ~b.jects and purp.-.6es f the preser1t inventif:rl, referen-e may be made t.. the f..ll.-.winQ U.S. F:<.~t. N.::.s~
f~nsiciered useful in pr..vidiny backQrc.urlri inf.-.rmatif.n: 4,6r:)C),3l4;
i~,3~5~37~; 4~3~-.),133; ~,56~ 4; f~,t.)~7,f35l; i~,3l3,ll~:~; 4,l5l,5~rr;
4,383,~5l; 4~ 045; 4,383,~53; 4,t:1~7~F3sc); What has been la.1:int~
in the pri-r art ..f sm 1te--dete-ti.n systems, the present inventi._.n hac. been dire teri t.. - cvercc.miny. ~ ~:
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O~JEI~rS OF T~IE II~IVENT:LON
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It is an ,-,bje,_t ,-,f the pre~5er,t inventi~_~n t,-, pr,-,vide a sm~k:e dete~t~,r which av~ids the inacdequal~ies ,-,f the l:nc,wn c.~mmer,~ially available smc.ke detect"rs ~alarms:~
It is an,-,ther c,bje,-t ,_,f the present inventi,-~n tc, prl-lvicle a safety sm,~ke alarm that i5 re,-haryable.
It is anl~ther c,bje,-t l-lF the present inventi~-~n tc~ pr_vide a safety ba.-kup systern t.. the primary pl~lwer s,_,urce, t,-, maintain ,-,ptimum ~_,perability during a diminishecl primary p,_,wer sc,ur,e ,_"nditic~n~
It is an"ther ,,bjert rlF the present inventic~n t,-, prl-lvide a smc,ke clete,-tic,n device which is capable l_lF being tempc~rarily silen.-ed and aut,_lmatil..ally re-activated~ whirh enables a h~mer~wner a pre-determined time interval t,_, cclrlk,f~m,~ke c,r any ,_,ther false fire conditi"n withn~lt haviny any crlncern ab,~ut thes alarm being Falsely ~et cff~
It is an,~lther c,bje,-t ,_lf the the present invention tc, pr,-,vicle an accessible wall mounted sml_lke alarm F"r easy cc,ntrc,l c,ver rlperaticln and maintenance,as well as vi~ibility clf indicat,-,rs and ease l:~f recharying.
SU~I~IARY OF THE IhlVEhlTION -. :.;.
Acc~rdingly, it is the primary c.bject ~:lf the present inventic~n tc~pr,_~vide a mcre adaquate, mc,re reliable smc.ke dete,-ti,-~n devi,~e with a safety pr.wer bark-up system,temp~.raYy silenciny features~ And be re~haryable~ as well as it must be within reach ~lf the hclmerwrler~
A sm~ke alarm that avr.ids the disadvantayes ..F the pri._.r art~
a mcre specifir c~bject, the present inventic.n prcvides fc.r a sm~ke alarm haviny a h4usiny and a unit c~r units in the h~usin~
f.~r detectiny smcke rr fire and pr.~duciny an audible siynal in resp~nse t~ the detecti.-.n, a manually a._uated c,~ntrc,l which eocperates with the detectiny and siynal prc.duciny means t,-, deactivate the audible siynal and aut.~matically reactivated the audible si~naliny means after a predetermined time interval~ the time delay .-ircuitry is sc~lid state and is in an r~ff state with virtually ncl quiescent pclwer dissipati4n, when this delay is activated the ciYuitry is supplied with p~wer c.nly fc~lr the time~
peric.d that it is enabled. Thus an eneryy eFficient timiny ~ircuit reduciny the ~urrent drain c~n the supply t,-, virtually ~er,_. in the ina~tive state~
' X01(~391 EIF~IEF DFSr;r~IF'TION or- Tl-IE DF.:AWIl~1l35 These and c,ther c,bje,-ts, Features and advantages will bec4me obvic,us Fr"m the Fc~ wing des,_ripti.:,n when ta~sen in ,:4njunrticlr with the a, ~-nnpanyiny drawin~s; in which:
FI~.l is a blclck dia~ram 4f a sm,~ke detectclr ,-::m~structed in accc,rdance with c,ne embmdiment "f the inventi,-,n.
FI~i.'' is schematic representaticln c~f the sm,-~ke dete~ti,-,n devi,_e.
FII,.3 is a timinrl clia~ram ,-,f the sm,-~ke detecti,-,n l ircLIit.
I:)ESI~RIP-rIOl~l OF PFEFEF~RED EM~ODIMENTS
F'eferring n"w to the drawinrls and in partil~ular t,-, FI~S.l and 2, a smc,ke dete, t,-,r cc~nstructed in accordanl~e with c,ne emb,_,diment ~IF
the present inventi4n i5 indicated gerierally at 5. The sm,lke dete~tc,r 5. in,~ludes tw4 elements, su::h as switch 1_, and 13, which are bl~th used to interact with the smoke detect~lr 5. by user acturlti,.n of the swit~-hes 12, and 13, The switch 12 ir~ a nc,rmally c~pen switch pushed tc, clc~se the cir,~uit fr,~m the ,-ontainer 14 definin~ an ic,ni2ati,-,n chamber 16. The i,-,ni2ati,-~r-,-hamber 16 it is a means fc,r sensin~ smc,ke levels and is a cclnventional unit having ran Americium is4tope sc,urce 17 ~AIvl-241:) supplied by Nuclear F.ariiaticln Development, ~uffalo, N.Y. The isotc,pe s4urce 17 emits alpha particles 18, and the i4ni2ation ,_hamber 16 is vented to admit smc.ke.- The alpha particles 18 ioni~e the atmosphere in the ioni2atic.n .-hamber 16 in a known manner, prc,vidin~ a.c4nductive path between the container 14 and the is4tope sour.-e 17. The voltage at c411ectc.r plate lg is potentiometrically divided between the voltage at the c4ntainer I4 and the isc.tope s4urce 17. It is a desi~n convenience that the isotope source 17 aIso functions as one conductive terminal c.f the ioni~atic.n chamber 16. The~intr~du~:ti4n 4F sm4ke int4 the ioni2ati.:,n. chamber 16 causes the:.v41ta~e at ~411e~~t4r plate :~:C) to chan~e~ in a known manner such that the v~ltage is a functic1n of the smoke levels in the ioni2ation chamber 16. When the user wi~shes to test the operability of the smoke detector 5. the use~
`pushes the switch 12 and appro~,;imately gO microamps current fl~ws from the Ni-~ad battery ~ having input terminal :;23. This current flows throu!ah resistor 24 into pin 7 clf dete~tor chip 60 during the testin~ mode when the switch 12 closes, a circuit to ground 61 i5 completed through resistor 62 and t4 ~around 61. These complete circuits therefore form a v~ltage divider netw4rk with a volta!3e on the container 14, of about 4.62 vdc, and thus a voltaç~e ~ of approximately 4,0 VD~ at collect4r plate ~0. This volta!ae is dependent on the manufacturers calibraticn of the ioni2ation chamber 16, in the test rnode the 4.0 VDC: input fr4m the~ collector plate 20 to the pin 15 i5 less than the v41tage of 4~S VD~ at the pin 13. This difference in voltage results in the volta!ae comparator section of the chip 60, outputtin~ an alarm si!ana} on pin 10 and 11, in conjuction with pin ~1, and als.-. with pin 5 to alarm !aenerating means,.- 6uch a~a a lisht emittinq diode 63 and a piezoelectric horn 64. The h4rn 6~ includes a pie20electric disk such as a l~ycera t~ ICPS-350A-3F~S-~
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manLl factured by ~YCEPA, LTD, JAPAN. The ,:eraml,- dink is m,-,unted in a transducer s~-~cket ~nc~t sh"wn1 pr,-,vides f,-,r an audi,-l ~-~UtpLIt ,-lf appr,_,~,;imate]y 85dE(. When the ,-hip 6C) strc~bes ~n the vc,ltar~e level "f ~.0 vric f,:,r the pin 13 ,:,-,rrespclnds tc~ ab~:~ut three per,-ent smc~ke clbsl~urati-ln level in the ic~ni~atil_ln chamber l6, fc,r the fclllc,win3 ~-c,nditi"ns the bufFered cc,llectic~n plate vc~ltar~e is plc~tted against sm,-,ke ~bscurati~-~n level in a sm,-,ke bcl~ with appr,-,~,;imately thirty-f,-,ur feet per minute air-fl,~lw and an initial vclltage ef the cclllectc,r plate ~C) is set t,-, ab,-,ut $~74 VDC, Durin~ n"rmal sensitivity clperati,-~n a predetermined sm~:~ke level Fc~r alarm si~nal ~eneratic,n is abl-lut ,-,ne and a half percrnt sm,ele clbsl-urati4ll ,_,r ,-,pti,al sm,,ke density. The sec,_,nd element switl-h 13. The swit,_h is a n,_,rmally c~pen swit,-h pushed t,-, ,lc,se the ,-ir,uit frc,m pin 4 rlf ~-hip 46 and pin 3 ,-,f ,-hip ~0 thus startin~3 the delay ,-ycle by activatin~ chip 45, pin 8. The time ,~,~nstant is cc~ntrnlled by the value clf F'1 and Cl ,_,f chip 45. The preferred embc,diment uses a ,-,-,nventi,-,nal timinrl circuit, but can ucie a variety c,f c,~mparat,~r ,-,r cc~unter ,-ircuits t,-, derive at a time delay. This circuit is then in cc~ntrc~l clf pin 3 ef chip 6C) lclw vc~ltar~e set input, circuit 45 then sets this vc,lt~rJe tc appr4~;imately ~J.C) vdc thus de~activatinq the alarm si~nal means by ~clin~ int,-, lclw v,-,lta~e mc,de, thus prclducinq a chirp sc,und every 6C) se,:c~nds t,-~ indi,_ate delay is c~n. The lclw v,-,ltage c,~mparat,~r infc,rmati,-,n is latched c,r unlat~-hed every 40 t,~ 60 seconds by a lC1 ms pulse. If an audible indicaticln by means ,~f a chirp s4und is undesirable, re-ccnfi~uraticln clf clutput pins 7~3y clf chip 45 tl- pin 6 clf chip ~0 de--activates alarm sensiny means c~f the detectcr fc,r the same time peri,~d but withl~ut the chirp indicatic,n. With the inclusicln cf a thermcl switch fr,_,m pin ~ c~f chip 60 tc~ pin 14 c~f chip 45 causes an clverride 4f delay circuit in case ~f an c~utbreak durin~ delay mode. The delay in the preferred emb,_~diment is determined tc~ be appr~imately ~Omin. The timin~ ~ device is independent and requires n~ p4wer durinq quiesent state, fc~r virtuc~lly ~er,_l pewer dissipati4n when n,lt used, an ener~y efficient desiqn. As well as when sm~ke is detected the resist,~r divider netw~rk that sets sensitivity is --altered tc~ increase sensitivity, this yeilds apprc,~imately lOC)mv 4f hysteresis and reduces false tri~qering. Durin~ depletion ~f primary vc~lta~e secti4n 40 4f S, will enable p~wer s4ur~e ~5 tc~ cut in when vc~lta~e falls bel,-,w 7.4 vdc, thereby qivin~ full p~wer tc~ chips 45,~6,6C), tc~ maintain ma~,;imum alarm ~apabilities.
5ectic~n 30 represents a lc~w v~ltaqe indicatic,n netwclrk includin~
a circuit that mc~nitc~rs the primary p~lwer sclurce~ When the sc~urce falls bel4w 7.4~vdc th~e circuit tri~qers -the L.E.D 14. ~ue t~ the ll~w duty cycle c~f the led 14 ~ lintronix F~L4403 ~ the avera~e current drain is lmA c,r less, the level clf sensitivity can be altered by ~3 c~f circuit 30. Input terminal ~3 is a dc input jack that is nc~rmally clc~sed c4mpletinq the pc,wer circuit.
~ut upc'n depleti4n the re-char~in~ prc~cess c4nsistinq clf a Nickel-cadmium battery char~er 4r transf4rmer with an input ~If OvAG 6C)H~ lW. Output 8.1 vdc 8mA, when input intc, terminal 23 this circuit is n4w isc,lated frc~m circuits ~,41:),30,45,4~,6C~, f4r the duratic~n _f the re-charqin~ pr~cess apprn~imately 14 h~urs.

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While the preferred emb~,diments of the present inventi,-,n have been illustrated and des,-ribed, it will be understc,l-ld that chanqes and mc~dificatic~ns may be made therEin withclut departinn from the invention in its br,_,ader aspe,_ts~ F,_,r e~,;ample the inventicln has been illustrated in terms ,_lf h ,_l~llectic~n c~f des-rete c"mp,-,nents, but it is ~_c,ntemplated that the circuitry ~-an be readily embc,died within an inteqrated cir,-uit chip~
varic,us features clf the inventi,ln are defined in tile fc~ winc~
claims~

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Claims (16)

1. A smoke alarm (detector) comprising:
means for sensing smoke levels and generating a signal responsive to said smoke levels:
means for generating an audible alarm responsive to said sensing means detecting a pre determined smoke density.
means for user to test the operability of said smoke alarm (detector), said testing means consisting of a single user actuated element adapted to cause generation of said alarm signal; and means for temporarily interuption of said alarm signal means for a pre-determined time interval by said second user element, adapted to activate said delay means.

2. The smoke detector as described in claim 1 wherein said sensing means comprises at least one of an ionization chamber/
radioactive source or photoelectric sensor system or capacitive shift method or any combination thereof of sensing systems.

3. A smoke detector comprising:
means for sensing smoke levels and generating a signal characteristic of said smoke levels: means for generating an alarm signal responsive to said sensing means detecting a predetermined smoke level, means for user testing the operability of the said smoke detector, said testing means comprising a user activated element adapted to cause generation of said alarm signal. And means for a temporary interuption of said smoke sensing means for a pre-determined time period by second user actuated element.

4. A smoke detector comprising:
means for sensing smoke levels and generating a signal characteristic of said smoke signals:
means for altering set sensitivity to increased sensitivity of said smoke detector by pre-determined smoke level.

5. The invention of claims 1, 2, 3, 4:
is a smoke detector for detecting the presence of smoke in the air of a space.

6. The invention of claim 5:
wherein said smoke detector(alarm) comprises an ionization chamber for providing said first output signal when smoke is in said chamber.

7. The invention of claim 3:
comprises an element used for setting a temporary interuption of said signal output of said smoke sensing means, Said timer means cont:
- provides for a reference output signal to have said annunciator respond periodically to said delay circuit activation, or not.

8. The invention of claim 7:
comprises a circuit consisting of an electronic arrangement to connect said second back-up power source when said main primary source has depleted below a predetermined level.

9. The invention of claim 8:
comprising an indicator circuit consisting of a power monitor monitoring the main primary power source. Having a visible indicator, consisting of an L.E.D or any lighting source to acknowledge depletion of said main power source.

10. The invention of claim 9:
comprising of a main power source and a secondary power source, and are both of the re-chargable nature. Example -nickel -cadmium or lead acid chemistry, the preferred is nickel-cadmium, charged through the detector housing into recharge terminal.

11. The invention of claim 9:
comprising of a circuit which monitors the said secondary backup power source, with an annunciator or visible indicator responding periodically to a low level of backup source.

12. The invention of claim 11:
comprises of said smoke detector having a visible indicator of system operability by second L.E.D. periodically pulsing.

13. A smoke detector of claims 1, to 13:
all circuits being housed in the interior of a rectangular housing, having passages on all four sides for admitting ambient air into the space within the housing passing into the ionization chamber.

14. The invention of claim 11:
comprises a housing that houses the two elements of user activation and the two L.E.D. indicators on the surface of the exterior of the housing for activation and visibility of operability of smoke detector.

15. A smoke detector of claim 14:
being housed in a rectangular plastic medium, it is the preferred embodiment of the present invention to mount the detection device on a vertical plane such as a wall and within reach of the user homeowner, for ease of control, re-charging, and cleaning, and visibility of indicators.

16. A smoke detector of claim 15:
consisting of two pieces, One is the base for permanent mounting on the surface of wall, and the second piece is the housing of the smoke detector which is secured in the base by means of catches on the base.