摘要:
A system for reducing the risk of waterlines freezing provides a solenoid controlled valve which may be cycled twice an hour for a minute (or longer if desired) to avoid ice buildup in the lines. The control circuit allows the homeowner flexibility in determining whether to allow the cycle timers (preferably 3 inexpensive timers) to control the solenoid valve's cycling directly or to permit a thermostat to intervene, cycling only when the set point of the thermostat is reached.
摘要:
A system for reducing the risk of waterlines freezing provides a solenoid controlled valve which may be cycled twice an hour for a minute (or longer if desired) to avoid ice buildup in the lines. The control circuit allows the homeowner flexibility in determining whether to allow the cycle timers (preferably 3 inexpensive timers) to control the solenoid valve's cycling directly or to permit a thermostat to intervene, cycling only when the set point of the thermostat is reached.
摘要:
A composition is provided which is suitable for use in a cleaning or washing process. The composition is contained in an aqueous sensitive device and includes at least one aqueous sensitive component and a non-aqueous carrier component for stabilizing said aqueous sensitive component. The non-aqueous carrier component includes a mineral oil and a gelling agent.
摘要:
A method of controlling a plurality of power converters 1a, 1b and 1c can be used to interface to a supply network, ac busbar etc. Each power converter includes a network bridge 14 operating in accordance with a pulse width modulation (PWM) strategy having the same switching period and which causes at least one unwanted harmonic in the supply network voltage. The method includes the step of providing the switching period of the PWM strategy of each network bridge with a different time offset relative to a time datum such that the at least one unwanted harmonic in the supply network voltage is at least partially cancelled. Two alternative ways of providing the time offset are described.
摘要:
A control system for controlling conversion of an input power into an output power in a converter module is provided. The control system includes an input power terminal, an output power terminal, and an active switching device. The control system further includes a master controller and a communication link interconnecting the master controller and the converter module. Also, the system has a timing generator generating a timing signal with a cycle time equal to or less than the shortest time constant of the converter module and immediate power circuit elements relating to the converter module. The timing generator is integrated in or interconnected with the master controller. Furthermore, the control system has a signal generator integrated in or interconnected with the master controller generating switching control signals, each switching control signal containing a control message defining a switching state for the active switching device.
摘要:
A method of controlling a power converter is used to interface to a power grid or supply network operating at a frequency (Fnet) that is nominally fixed (say at 50 Hz, for example) but which can be varied as a way of controlling power imbalanced within the network as a whole. The power converter can include a network bridge that operates in accordance with the pulse width modulation (PWM) strategy having a switching frequency (Fpwm), a nominal switching frequency (Fpwm_nom) and a number of pulses per period (Pulse_Number). The method includes the step of varying the switching frequency (Fpwm) of the PWM strategy in accordance with the time-varying frequency (Fnet) of the supply network to achieve only integer odd harmonics of the time-varying frequency (Fnet) and the step of adjusting the number of pulses per period (Pulse_Number) in accordance with the time-varying frequency (Fnet) of the supply network to maintain a switching frequency (Fpwm) that is less than, or equal to, the nominal switching frequency (Fpwm_nom).
摘要:
The illustrative embodiments provide a method and an apparatus for writing a shortened text message using a wireless mobile device. An editor receives longhand text written through a user interface for the wireless mobile device. The editor then matches the longhand text with at least one shortened equivalent. A user interface then displays the at least one shortened equivalent. Responsive to receiving a user input accepting the at least one shortened equivalent through the user interface, the editor replaces the longhand text in a message with the at least one shortened equivalent.
摘要:
A swing-check valve for controlling fluid flow includes a valve housing and a valve assembly connected to a removable cover of the valve housing for rigid positioning of the valve assembly within the interior of the valve housing. Moreover, the valve assembly includes as a modular unit a valve seat subassembly in addition to a clapper subassembly and a spring subassembly. The valve seat subassembly includes a valve seat that is frictionally disposed within a port of the valve housing for controlling fluid flow therethrough when the cover is fastened to the valve housing. The clapper subassembly includes a clapper pivotal between a first position in engagement with the valve seat for blocking fluid flow through the port and a second position for permitting fluid flow through the port. The spring subassembly includes a spring and a spring base engageable with the clapper subassembly for urging the clapper into the first position. In one embodiment, the clapper subassembly includes a roller which engages the spring base and, in another embodiment, the clapper subassembly includes a cam member which engages the spring base. No fasteners are provided for the valve assembly within the interior of the valve housing and, furthermore, upon the unfastening of the cover, the valve assembly can be removed as a single unit from the valve housing by simple manipulation and removal of the cover.
摘要:
The present invention is embodied in a ceramic matrix composite, comprising a ceramic fiber, a multi-layer coating on the fiber comprising plural alternating layers of an easily-cleaved material and an oxidation resistant material, and a ceramic matrix contacting the coating, the fiber and coating being embedded in the matrix.