Abstract: A flow sensor for detecting the absence of a minimum fluid flow in a sprinkler system. The fluid acts upon a vane positioned in the fluid path. Movement of the vane controls the position of a slider. The slider's surface has reflective and non-reflective ends which, in response to the vane's movement, reflect or absorb light from a light emission and detection means. The voltages from the light emission and detection means are monitored for indications of the fluid flow. The sensor uses a two wire signal transmitting system.

Abstract: An electric switch actuating mechanism for use in monitoring fluid control valves such as those used in fire services controls a micro-switch (5) or electronic switch which forms part of an external supervisory circuit. The switch (5) is housed within a common housing (8) with the mechanism. The mechanism comprises a pivoting actuator (24) which is spring (27) biased to a first position and may be pivoted to a second position to actuate the switch (5) by an operator (28). The operator (28) is contacted from externally of the housing by a contact member (38) on a valve spindle (51) when the valve is in the normally open position. The actuator (24) is on a floating pivot (26) and is held in proper operating position by push-rods (36) and pins (37) which are retained in position by a lid (2) of the housing. When the lid is removed the pivot (26) moves to a position wherein movement of the operator (28) will not cause the actuator (24) to operate the switch (5).

Abstract: A flow sensor for detecting the absence of a minimum fluid flow in a sprinkler system. The fluid acts upon a vane positioned in the fluid path. Movement of the vane controls the position of a slider. The slider's surface has reflective and nonreflective ends which, in response to the vane's movement reflect or absorb light from a light emission and detection means. The voltages from the light emission and detection means are monitored for indications of the fluid flow. The sensor uses a two wire signal transmitting system.