Patent GB-642644-A (GB)
Title: Alarm arrangement, especially for fire alarms and the like
Inventor: LINDHOLM JORGEN PREBEN
IPC: G08B17/06
Filed: 1946-02-04
Abstract: 642,644. Indicating and locating faults. AKTIEBOLAGET FRILI. Feb. 4, 1946, No. 3417. [A Specification was laid open to inspection under Sect. 91 of the Acts, April 22, 1946.] [Class 37] [Also in Groups XXXVII and XXXVIII] An alarm system includes fault indicating relays which lock on the occurrence of a fault and are re-set manually after the fault has been corrected. Fire alarm.-Fire occurring e.g. at substation 1, Fig. 1, causes at least one heat-sensitive device SI1, SI2 to sever both its links to de-energize relay AR, to light a lamp SL1 and open contacts AR1 and AR2 to deenergize both relays GAR1, GAR2 at the central station III, thus actuating both alarm bells K1, K2, lighting lamps GL5, GL6 and sending a code signal to a fire brigade station. Switch 08 stops the bells and lights lamp GL4. Fault alarm.-If loss of continuity develops in one only of the leads to relay AR1, one or other of the windings of relay FR1 is deenergized to light the lamps SL1 indicating at which substation the fault is present, to open contact FR1, to de-energize relay GFR at the central station, thus lighting defect indicating lamp GL2, ringing bell FKL and disconnecting the code-sender. Switch 06 stops the bell FKL and lights lamp GL3. Relay FR1 is released by moving switch O, to position FR to reenergize relay GFR and extinguish lamp GL2, to light lamp GL1 to indicate that afire alarm circuit is out of order, to extinguish lamp SL1 and to energize relay AR1 over switch 03. Testing supply circuits IV, Fig. 1.-Meter MA normally across resistances r1, measures the voltage supplied to the system ; switch 09 connects the meter across resistance r2 to measure the output of rectifier LL, switch O10 connects the meter to measure the voltage of the battery B ; switches O11 and 012 connect it respectively between earth and each terminal of battery B to detect earth leakages which can be localized in the system by operation of switches O1 011, O3 switching off various circuits in succession. A large earth leak energizes relay winding IJR which closes the circuit of winding IIJR to light signal lamp SFL2 and actuate defect relay GFR at the central station III ; switches 019, 020 restore relay JR. Switch O18 tests relay JR. Switch 019 tests lamp SFL2. Switch 013 connects the meter across resistance r3 to measure charging current of Battery B, and a reversing switch 014 permits discharging current to be measured. If the rectifier LL develops a fault, winding 1 of relay LR de-energizes to de-energize relay BR to light signal lamp SFL1. Switch 016 tests relay BR. Testing alarm circuits.-To test relay FR1, switch O1 is brought to the position Fr and switch 04 closed to short circuit the windings of relay Fr1 so that a fault alarm is signalled if the relay FR1 is satisfactory. Relay AR1 is tested by bringing switch O1 to position Fe and opening switch 03 to de-energize relay AR1 to produce a fire alarm signal. The fault alarm bell FKL is tested by switch 05, while switch 07 test fire alarm bells k1, k2. Relays.-Preferably relays AR, FR are associated as in Figs. 3, 4, with the signal lamps SL. Leaf-springs 21, 22 have slots and bear against members 25, 26 carried by the armatures 23, 24 of the relays, so that when the relays are de-energized, the armatures are locked against movement until released by switch O which disengages the springs 21, 22 from the members 25, 26. Alternatively, the relays may be locked in the un-energized condition by breaking its own circuit on de-energization, Fig. 2 (not shown).