Abstract: A device and system for purifying a fluid is provided. The system includes a tank having an interior space and a media container disposed within the interior space. A valve is provided that cooperates with an element within the interior, the valve being movable between an open and a closed position. The valve being biased to the open position when the element is not positioned within the interior space, wherein the interior space is fluidly coupled to the atmosphere in the open position. The valve further being configured to move to a closed position when the element is positioned within the interior space.

Abstract: A device and system for purifying a fluid is provided. The system includes a tank having an interior space and a media container disposed within the interior space. A valve is provided that cooperates with an element within the interior, the valve being movable between an open and a closed position. The valve being biased to the open position when the element is not positioned within the interior space, wherein the interior space is fluidly coupled to the atmosphere in the open position. The valve further being configured to move to a closed position when the element is positioned within the interior space.

Abstract: A water heater including a tank having a wall with an external surface and an internal surface defining an interior, and a circuit board mounted to the external surface of the tank. The circuit board including a thermal path for conducting heat through the circuit board, where the thermal path of the circuit board is thermally coupled to the external surface of the tank. An electronic switch is mounted to the circuit board and electronically coupled to a heating element, where the electronic switch is thermally coupled to the thermal path of the circuit board so that heat generated by the electronic switch is transferred along the thermal path. A temperature sensor is thermally coupled to the circuit board to sense a temperature of the thermal path relating to a temperature of the electronic switch and relating to a temperature of water stored in the tank.

Abstract: A low-cost, two-wire, half-duplex high speed powered communications bus having a master/controller and one or more slave/sensor/interface units. The master/controller may have a current-limited power supply, and receive/transmit circuitry. Each slave/sensor/interface may have polarity protection and also have receive/transmit circuitry. The power supply may provide high/low voltage levels on the bus and over-current protection, and have one or more diodes for mis-wire protection. Each transmit circuit may have a tunable R-C network for limiting RF emissions. Each slave/sensor/interface may receive data and power over the two-wire bus.

Abstract: A system for adjusting a bias voltage of a flame sensing system. The system may use pulse width modulation to adjust the bias voltage. The system may have a flame sensing rod that conveys an electrical equivalent circuit of a flame presence to a detector via low pass filter. An excitation voltage may be conveyed via a DC blocking mechanism to the sensing rod. A pulse width modulation signal may be conveyed via a bias resistor to a node of the low pass filter and the detector. The input of an A/D converter may be that of the detector for flame signals. Also, leakages between the node of the A/D converter connection and the voltage source and/or ground may be detected and compensated. Further, leakage of the DC blocking mechanism may be minimized.

Abstract: A low-cost, two-wire, half-duplex high speed powered communications bus having a master/controller and one or more slave/sensor/interface units. The master/controller may have a current-limited power supply, and receive/transmit circuitry. Each slave/sensor/interface may have polarity protection and also have receive/transmit circuitry. The power supply may provide high/low voltage levels on the bus and over-current protection, and have one or more diodes for mis-wire protection. Each transmit circuit may have a tunable R-C network for limiting RF emissions. Each slave/sensor/interface may receive data and power over the two-wire bus.

Abstract: A gas valve body with a first flow chamber and, a second flow chamber including and a main valve positioned in line and between the first flow chamber and the second flow chamber. The main valve can be opened by creating a pressure differential across the main valve. An electrostatically controlled pilot valve is provided for controlling the pressure differential across the main valve for “on-ff” operation. The electrostatically controlled pilot valve may also be operated to “modulate” the pressure differential across the main valve along a range of pressure differential values.

Abstract: A water heater control system that prevents the accumulation and accidental ignition of dangerous quantities of unwanted flammable vapors. The system intermittently generates a spark at a predetermined interval such that if unwanted flammable vapors are present, they are burned in a controlled manner. The system obviates the need for flammable vapor sensors.

Abstract: A water heater control system that prevents the accumulation and accidental ignition of dangerous quantities of unwanted flammable vapors. The system intermittently generates a spark at a predetermined interval such that if unwanted flammable vapors are present, they are burned in a controlled manner. The system obviates the need for flammable vapor sensors.

Abstract: A controller area network (CAN) has a plurality of nodes connected to transmit and receive data over a serial data line using an interface circuit to connect the node to the data line. Each interface circuit includes an isolation element, typically a diode, to connect the interface circuit to the data line. An indicator element in the interface circuit is powered when the node is transmitting. The isolation element in each node prevents other nodes while transmitting, from powering the indicator element in its node.

Abstract: A controller area network (CAN) has a plurality of nodes connected to transmit and receive data over a serial data line. An AC power source is also connected to each node. Each node senses the AC power waveform and synchronizes bit transmission and bit detection with the waveform. In a preferred embodiment, each node includes a circuit that detects zero crossings by the AC waveform, providing two accurately synchronized bit intervals per complete AC cycle. A preferred version of the invention includes hardware and software that detects miswires of the node to the data and power lines.

Abstract: A disarmable firing module with a firing module housing having an opening therein; a detonator holder received in the firing module housing via the opening in the firing module housing, the detonator holder including a cavity therein; a detonator disposed in the cavity of the detonator holder; and a detonator electronics assembly housed within the firing module housing. The detonator holder is removably secured within the housing which allows the detonator to be separated from the detonator electronics assembly to disarm the firing module.

Abstract: A detonator with a base portion including opposing electrical leads; an exploding foil initiator on the base portion, the exploding foil initiator including two conductive lands separated by a bridge portion therebetween; and a connecting barrel of a predetermined thickness on the exploding foil initiator for optimizing the spacing between the exploding foil initiator and an explosive charge and for robustly interconnecting the lands of the exploding foil initiator with the electrical leads of the base portion.

Abstract: A detonator with a base portion including a header wall terminating in a support surface; an initiator on the support surface; an explosive charge spaced from the initiator; and a cap having an interior top surface and an enclosure wall extending downward from the interior top surface and surrounding the initiator and the explosive charge. The wall terminates in a rim secured at a location along the header wall corresponding to the thickness of the initiator, the spacing between the initiator and the explosive charge, and the thickness of the explosive charge thereby ensuring that the explosive charge is in communication with the interior top surface of the cap.

Abstract: A solid-state fail safe gas valve system in which first and second gas valves are arranged in series in a gas passageway, the valves being actuatable by first and second solenoid operators respectively, the second operator requiring a voltage greater than the operating voltage supplied to the valve system to achieve actuation. The operators are separately energized through microprocessor controlled switches so that a capacitor connected across the second operator and its switch is pumped to a voltage above the supplied voltage by voltage induced by interrupted energization of the first operator.

Abstract: A flame rectification type flame sensor circuit and method in which a generator injects periodic pulses of alternating voltage into a flame region, the voltage across the flame region being processed by a filter/amplifier which, in proper operation, produces a non-zero output signal only during the time a flame is present and a pulse of alternating voltage is being supplied by the generator. Final indication of a flame is produced only if a non-zero output signal occurs during the time a pulse of alternating voltage is being supplied, and not during the time between successive pulses of alternating voltage. Failure of an electrical component in the filter/amplifier is indicated if a non-zero output signal occurs during the time between successive pulses of alternating voltage.

Abstract: An interface circuit is designed to connect a first logic circuit such as a microcontroller with a second similar microcontroller using three wires and allowing for simultaneous transfer of data from each of the microcontrollers to the other. A transmitter element in each interface circuit has a bias resistor which cooperates with a pull-up resistor in the other interface circuit to provide an indication for one of the logic circuits when the other of the logic circuits and its associated interface circuit loses power or when one of the three connecting wires is disconnected.

Abstract: A method and apparatus provide input protection in a system having a controller which monitors a controller terminal for at least one monitor period. The controller terminal is coupled for bi-directional operation. The controller terminal is set to an output configuration for at least a portion of the time that the controller terminal is not being monitored by the controller.

Abstract: An apparatus and method for providing a microprocessor having an inaccurate oscillator with a desired time base. The cycles of the output signal of the oscillator are counted by a first counter until the counted number equals a predetermined correction count. The first counter then produces a timing signal. A second counter is set up to create an actual count indicative of the number of output signals occurring during a predetermined number of periods of an AC signal generator connected to the microprocessor. A predetermined desired count is then subtracted from the actual count to produce a difference count. The difference count is then added to the old correction count to create a new correction count. By iterating this process until the difference count is equal to zero, the timing signal is modified until it is equal to the desired time base.

Abstract: A recovery algorithm for a setback thermostat uses the intersection of the space temperature with a sloped recovery temperature line which approximates the change in temperature as a function of time during recovery of the temperature controlled space from a setback temperature, to determine the time at which recovery to the occupancy temperature should begin. The thermostat starts recovery when the current space temperature crosses the recovery temperature line. A useful feature of the apparatus and method which implement the invention, computes and constantly updates the slope of the recovery temperature line. The update of the recovery temperature line slope is based on miss time, i.e., the time between actually achieving the desired next set point temperature and the next set point time associated with the next set point temperature.