Abstract: A purge control device for an evaporative control system comprises a single housing having two solenoid actuated valves controlling parallel orifices leading from an inlet chamber to an exit flow path. The two solenoid valves have different sized orifices to provide different flow capacities. Purge flow is controlled by an electronic control module which regulates the duty cycle of the solenoids. Each valve receives its own signal so that the flow through the orifices is individually controlled.

Abstract: A device for detecting a malfunction of the evaporative control system comprises a two-way flow device in the atmospheric air vent of the evaporative canister with a sensor to detect whether fluid is flowing through the canister during selected operating conditions.

Abstract: A vapor storage canister has an improved carbon bed loading pressure maintenance mechanism. A pressure plate is driven up indirectly, through a threaded shaft turned by a radially wound spiral spring, rather than by an axially compressed helical spring. This takes better advantage of the space available between the carbon bed and the lower end of the canister.

Abstract: The disclosure relates to a linearizer circuit capable of substantially replicating a non-linear waveform on a piece-wise linear basis by providing a pair of circuits, one capable of reducing the slope of an output circuit curve when a predetermined output level has been reached and the other capable of increasing the slope of an output circuit curve when a different predetermined output level has been reached. Such circuits are cascaded in required order and with predetermined slope parameters to replicate a non-linear curve on a piece-wise linear basis.

Abstract: The disclosure generally relates to a protective device for an electronic instrument wherein input and output lines to and from the instrument are always isolated from calibration input and output terminals. This is accomplished by placing reed switches on or closely adjacent the non-magnetic instrument front panel, the switches being arranged to connect one of the input lines and terminals to the instrument circuitry while disconnecting the others therefrom, this being accomplished under control of a magnet placed adjacent the switches during a calibration procedure. The switches are further arranged to short circuit the output test terminals in the unenergized switch state to prevent insertion of unwanted signal current or voltage in that state.

Abstract: Disclosed herein is a self-regulating hydrant which is characterized by a mechanism which automatically alters the flow of fluid through a valve seat in response to changes in ambient temperature. A temperature-responsive member, operatively coupled to a valve plug, is used to control the position of the plug relative to a valve seat. As the temperature of such member changes, its dimensions change. Such dimensional changes are preferably amplified and used to move the plug relative to the valve seat to control the rate of fluid flow through the valve seat.

Abstract: A smoke detector and alarm utilizing two photo resistors, one of which is used to detect smoke in an enclosed chamber and the other of which is used to compensate for line voltage variations and the effect of such variations on the smoke detecting photo resistor, and to supervise or monitor the light source so as to detect and signal light source failure in a distinct way.