Multiple operating alarm systems employing oil burner flame monitoring relays

Claim 1

A multiple alarm system for monitoring the status of an area to be protected, comprising: a. a series path sensor string including a relay coil in said path, said relay coil associated with at least a first contact, said contact capable of being in either one of two states; wherein is one of said states, said contact is closed and in said other state, said contact is opened, b. first illumination means coupled to said contact and said illumination means operative to provide a light beam, when said coil is energized, c. light responsive means responsive to said light beam to detect a transition from dark to light to provide upon detection of said condition, an output signal of an indefinite duration and operative upon detection of a light to dark condition to provide a predetermined duration signal, which signal will undesireably reset said light responsive means, d. time delay means responsive to said predetermined signal and operative after a delay less then said predetermined duration signal to provide an output signal before the termination of said predetermined delay, e. second illumination means responsive to said output signal of said time delay means to illuminate said light responsive means independent of said first illumination means to thereby assure that said predetermined duration signal does not reset said light responsive means whereby when said series string is broken and said coil is no longer energized, said light responsive means produces said indefinite duration signal, and f. alarm means responsive to said indefinite duration signal to provide an indication when said series sensor string is broken.