Abstract: The performance of an HVAC system in a building is monitored by connecting a thermostat to an alarm system which is equipped to provide notification of alarm conditions through telecommunication or other direct means to some responsible entity. The alarm system access to telecommunications is employed to forward indicators of HVAC fault to predetermined offsite locations from where corrective action can be provided. The system includes a presumed fault condition processor which employs data from the thermostat to indicate to the alarm system that notification should take place.

Abstract: A furnace (A) defines a combustion chamber (10) in which a pair of burners (B) are mounted for oxidizing the fuel to heat the combustion chamber. An air blower (12) supplies air to the burners at a rate controlled by a rate control valve (18). A frequency modulated burner control system (C) controls the duty cycle of the burners, i.e. cyclically actuates the burner at a fixed burn rate and then deactuates them. The burner control system varies the actuation to deactuation ratio in each cycle to vary the thermal input to the combustion chamber. The burners provide two - stage combustion wherein a fuel rich mixture is partially oxidized in a first stage combustion area (44). Additional air which is thereafter introduced through air passages (50, 52) completes the combustion.

Abstract: A cooking appliance using a gas fuel as a heat source and having an appliance body includes comprising a temperature sensor installed in a heating chamber, a control circuit adapted to be actuated by the output from the temperature sensor and to operate according to three working temperatures, namely, a preset temperature, an upper limit temperature and a lower limit temperature, the arrangement being such that when the temperature in the heating chamber being detected by the temperature sensor reaches the upper limit temperature, the main burners are completely closed; when it reaches the preset temperature, the firing of the main burners is reduced by half; and when it reaches the lower limit temperature, the main burners are fully opened, thereby effecting fine temperature control, the firing rate being automatically adjusted according to variations in external conditions affecting the heating chamber temperature, thereby maintaining the preset temperature throughout the heating operation to provide a sati

Abstract: An efficient method for using a periodic kiln to heat ceramic material to a state of maturation, and the apparatus for carrying out the method, duplicate the action of pyrometric cones. In a microcomputer, data is stored describing the relationship between rates of temperature increase and deformation temperatures for several numbered pyrometric cones. The kiln operator selects the cone number for use in the firing operation and then activates both the apparatus and the kiln's heating elements. Using a thermocouple, the microcomputer periodically measures kiln temperature and calculates the average rate of temperature increase inside the kiln (the rate need not be controlled). The rate is then used, in conjunction with the stored data, to determine the temperature at which the ceramic material will have matured. If the present temperature in the kiln is greater than or equal to this maturation temperature, the microcomputer sounds an alarm or shuts off the heating elements.

Abstract: Apparatus and a method for controlling the flow of a fluid to a fluid-actuated system. The system is controlled by a sensor which senses a variable characteristic of the system, such as the air temperature. The apparatus includes a pair of solenoid valves, one valve being set to deliver a first volume of fluid per unit time and the other valve being set to deliver a second volume of fluid per unit time. The solenoid coil of one of the valves responds to the actuation and de-actuation of the sensor. The second valve has a solenoid coil controlled by a pair of switches. One of the switches is responsive to a first timing signal and the second switch is responsive to a second timing signal. One of the switches allows the second valve to be open for a first time interval during which the first valve is open; thereafter, the second valve is closed.

Abstract: A timing mechanism to control the sequential progressive opening of a valve in a gas line leading to a gas fired kiln with the sequential progressive openings taking place at predetermined time intervals until the object being heated in the kiln has matured. Once maturation has taken place, the valve is sequentially progressively closed at predetermined time intervals in order to allow the kiln to cool down slowly. Adjustable controls are provided in order to allow the user to vary the time period between the progressive further opening of the valve and also the degree of opening of the valve to take place at each activation thereof.

Abstract: A thermostatic controller system for a building heating and/or cooling system (furnace) includes a stored program of desired temperatures which are to be attained within the building at predetermined times within a repetitive time cycle, such as a day. Differing environmental conditions externally of the building result in differing rates of change of temperature within the building upon operation of the furnace. In order to determine the optimum time to switch the system on to meet the next programmed increased temperature, the furnace is switched on and then off a short period of time later and the temperature change which results in the building as a result of that transient operation is measured. The time at which the furnace must be switched to attain the next programmed temperature is then determined as a function of the rate of temperature change as determined by the transient switching and the difference between the instantaneous and the future programmed temperature.

Abstract: A startup and shutdown control for a cryogenic freezing tunnel for freezing food products in which the rate of flow of cryogen into the tunnel is normally regulated by a thermal regulator, including an auxiliary flow regulator for maintaining a predetermined flow of cryogen to the tunnel independently of the thermal regulator, a first startup interval device, comprising a counter responsive to movement of the tunnel conveyor, for actuating the auxiliary flow regulator to provide a constant flow of cryogen to the tunnel after a first startup interval measured from the initiation of movement of a supply of food products to the tunnel, and a second startup interval device, comprising a timer, to cut off the flow of cryogen via the auxiliary flow regulator after a second startup inverval.

Abstract: A radiant furnace for firing ceramic material provides for accurate control over the rate of increase of the ceramic material temperature during a firing operation. Heat is radiated in the furnace from an electrically controlled heater. A first programming signal is produced to represent a manually selected rate at which the temperature is to be raised, and a second programming signal is produced to represent a manually selected target temperature beyond which the ceramic material temperature is not to be raised. Circuitry responsive to the first and second programming signals produces a command signal varying in magnitude to define a ramp having a peak value. The command signal is applied to a closed-loop heating control subsystem employing a thermo-sensitive transducer for providing a feedback signal.