Abstract:
An apparatus controls the treatment of water that flows through a cooling system. The electrical conductivity of the water is sensed. A valve control opens a system drain valve when the sensed conductivity is greater than a threshold, and closes the drain valve when the conductivity drops below the threshold by a given amount. The water drained form the system is replenished through an inlet and a mechanism measures the volume of water added to the cooling system. Chemicals to treat the water are fed into the system when specified volumes of water have been added. The sensing of conductivity can be inhibited for a certain period following the application of the chemicals. A possible system malfunction is indicated when the conductivity does not drop below the threshold after the drain valve is open for a given period of time.
Abstract:
The present invention is directed to a method and apparatus for measuring a magnetic field and determining whether an anomaly is present based on the magnetic field measurement and a measured ambient magnetic field. The present invention is also directed to a method and apparatus for measuring the intensity of the magnetic field by implementing operations to essentially eliminate error components that arise due to factors including offsets and gains affecting the intensity signal processing.
Abstract:
A line isolation monitor (LIM) indicates the maximum hazard current of an ungrounded polyphase power distribution system. The LIM is microcontroller based and continuously monitors a fault impedance for the distribution system. The fault impedance is determined by the LIM by injecting a continuous sine wave measurement current into a ground terminal to generate a measurement voltage across the fault impedance. Using the measurement voltage and current, the LIM calculates the fault impedance and, using this impedance, calculates the hazard current based on the maximum line to ground voltage of the ungrounded system. The LIM has means for self-calibration and self-testing while on-line and during a power-up sequence to verify that components in the measurement circuitry are within specified tolerances.
Abstract:
An apparatus controls treatment of water flowing through a boiler and includes a device that monitors the conductivity of the water. A controller opens a drain valve at periodic intervals, and closes the drain valve when the conductivity drops below a defined threshold. A mechanism measures the volume of water that flows into the boiler and a chemical is added to the water when a specified amount of water has flowed into the boiler. Alternatively the application of the chemical can occur at regular intervals of time. The chemical is applied for a user definable period of time. The application of the chemical is suspended when the cessation of water flow into the boiler is detected.
Abstract:
A line isolation monitor (LIM) indicates the maximum hazard current of an ungrounded polyphase power distribution system. The LIM is microcontroller based and continuously monitors a fault impedance of the distribution system. The fault impedance is determined by the LIM by injecting a continuous sine wave measurement current into a ground terminal to generate a measurement voltage across the fault impedance. Using the measurement voltage and current, the LIM calculates the fault impedance and, using this impedance, calculates the hazard current based on the maximum line to ground voltage of the ungrounded system. The hazard current is displayed and if it exceeds a predetermined threshold, the LIM will provide audio and visual alarms. A serial communications channel allows the LIM to communicate with other intelligent devices. The LIM has means for self-calibration and self-testing while on-line and during a power-up sequence. Line frequency is also determined by the LIM. Two LIMs can be used to monitor the same distribution system at the same time without interfering with each other.
Abstract:
A line isolation monitor (LIM) indicates the maximum hazard current of an ungrounded polyphase power distribution system. The LIM is microcontroller based and continuously monitors a fault impedance for each phase of the distribution system. The fault impedance is determined by the LIM by injecting a continuous sine wave measurement current into a ground terminal to generate a measurement voltage across the fault impedance. Using the measurement voltage and current, the LIM calculates the fault impedance and, using this impedance, calculates the hazard current based on the maximum line to ground voltage of the ungrounded system. The LIM has means for self-calibration and self-testing while on-line and during a power-up sequence. These tests compare measured and theoretical values of circuit parameters of voltage and current sensing circuits. During this calibration check, the monitoring circuits of the LIM are removed from the isolated system and known voltage and current signals are injected internally to the monitoring circuits to verify the component parameters. If the calibration parameters are outside tolerances by a first, low level, the LIM annunciates a warning, but will continue to monitor the hazard current. If the deviation is greater than a second, higher level, the LIM will indicate a fault and remove itself from service.
Abstract:
Apparatus, systems and methods for dispensing sheet material from a roll which include a low-material sensing system. The low-material sensing system provides an indication when the sheet material approaches depletion or is depleted so that the depleted sheet material roll can be replaced with a full roll. The low-material sensing system determines that the sheet material is depleted or near depletion by comparing the rotational speed of a sheet material roll from which the sheet material is unwound with the speed of the motor which produces movement of the sheet material roll when power is supplied to the motor. The sheet material roll speed increases as material is unwound while the motor speed remains relatively constant. A low-material indication is provided when the comparison reaches a threshold representative of the low-material state.
Abstract:
A transceiver unit includes an oscillator which generates a pulse train to a transceiver counter that connects to a display. The pulse train is also coupled by means of coils to a counter contained in a portable transponder unit which attaches to the animal. The transponder unit counter counts in synchronism with the transceiver counter and it generates a reset pulse when it counts a preselected number of the pulses. This reset pulse is coupled by means of coils to the transceiver unit. The preselected number corresponds to the identification number of the animal and the reset pulse reads this number out of the transceiver counter to the display.
Abstract:
Apparatus, systems and methods for dispensing sheet material from a roll which include a low-material sensing system. The low-material sensing system provides an indication when the sheet material approaches depletion or is depleted so that the depleted sheet material roll can be replaced with a full roll. The low-material sensing system determines that the sheet material is depleted or near depletion by comparing the rotational speed of a sheet material roll from which the sheet material is unwound with the speed of the motor which produces movement of the sheet material roll when power is supplied to the motor. The sheet material roll speed increases as material is unwound while the motor speed remains relatively constant. A low-material indication is provided when the comparison reaches a threshold representative of the low-material state.
Abstract:
Towel dispensing methods and automatic towel dispensers permitting conservation of the overall amount of towel dispensed. The towel dispensing methods and towel dispensers limit the amount of towel dispensed in dispense cycles which occur shortly after an initial dispense cycle. The user is provided with sufficient towel to meet the user's needs while reducing overall towel usage and limiting towel waste.