Abstract: An air purification system is provided which includes measurement of a concentration of a target pollutant within the air. A gas sensor is used for sensing a concentration of the pollutant (although it will detect other pollutants as well due to cross-sensitivity). A filter is provided which selectively removes the target pollutant while having a significantly smaller effect in reducing other pollutants to which the sensor is cross-sensitive. A gas sensor response is obtained before filtering, a gas sensor response after filtering, and the sensitivity characteristics of the gas sensor to the pollutant are processed, thereby to determine a gas concentration of the pollutant in the air before filtering. In this way, the concentration measurement is better than a direct measurement with the gas sensor as a result of a low selectivity of the gas sensor.

Abstract: An air purification system is provided which includes measurement of a concentration of a target pollutant within the air. A gas sensor is used for sensing a concentration of the pollutant (although it will detect other pollutants as well due to cross-sensitivity). A filter is provided which selectively removes the target pollutant while having a significantly smaller effect in reducing other pollutants to which the sensor is cross-sensitive. A gas sensor response is obtained before filtering, a gas sensor response after filtering, and the sensitivity characteristics of the gas sensor to the pollutant are processed, thereby to determine a gas concentration of the pollutant in the air before filtering. In this way, the concentration measurement is better than a direct measurement with the gas sensor as a result of a low selectivity of the gas sensor.

Abstract: The present invention relates to a humidifier and a method of monitoring the water level in the humidifier, the method comprising the steps of: detecting the temperature at the air outlet of the humidifier and generating temperature signals indicating the temperature thereof (310, 410); determining the water level in the humidifier according to the generated temperature signals (330, 430). The water level in the humidifier can be monitored using a rather simple structure yielding a high accuracy.

Abstract: The present invention relates to a humidifier and a method of monitoring the water level in the humidifier, the method comprising the steps of: detecting the temperature at the air outlet of the humidifier and generating temperature signals indicating the temperature thereof (310, 410); determining the water level in the humidifier according to the generated temperature signals (330, 430). The water level in the humidifier can be monitored using a rather simple structure yielding a high accuracy.

Abstract: A wake-up lighting device is described, comprising a gas discharge lamp (10) and a lamp driver (1; 2) comprising a power source (100) capable of generating spaced-apart current bursts (51) of alternating lamp current (I). The wake-up lighting device is capable of operating in an off-mode in which no lamp current is generated, and is adapted to switch from its off-mode to a wake-up mode in which the power source (100) operates to:—initially generate an alternating lamp current (I) with a minimum duty cycle value (?T) and a reduced current amplitude (IR) close to zero;—subsequently gradually increase the current amplitude while keeping the duty cycle (?) constant at the minimum duty cycle value (?T), until the current amplitude reaches a nominal current amplitude (IM);—subsequently gradually increase the duty cycle (?) while keeping the current amplitude constant at the nominal current amplitude (IM).

Abstract: A compact gas discharge lamp (301) comprising four (or more) interconnected tube segments (11, 12, 13, 14) is provided with an external electrode (310) that extends at least throughout the length of the tube segments and that is in contact with all tube segments. Several embodiments of the external electrode are disclosed. The external electrode is preferably connected to a node (C) midway between the lamp electrodes, to which end a capacitive divider (441, 442) is arranged in parallel with the lamp.

Abstract: A wake-up lighting device is described, comprising a gas discharge lamp (10) and a lamp driver (1; 2) comprising a power source (100) capable of generating spaced-apart current bursts (51) of alternating lamp current (I). The wake-up lighting device is capable of operating in an off-mode in which no lamp current is generated, and is adapted to switch from its off-mode to a wake-up mode in which the power source (100) operates to:—initially generate an alternating lamp current (I) with a minimum duty cycle value (?T) and a reduced current amplitude (IR) close to zero;—subsequently gradually increase the current amplitude while keeping the duty cycle (?) constant at the minimum duty cycle value (?T), until the current amplitude reaches a nominal current amplitude (IM);—subsequently gradually increase the duty cycle (?) while keeping the current amplitude constant at the nominal current amplitude (IM).

Abstract: A compact gas discharge lamp (301) comprising four (or more) interconnected tube segments (11, 12, 13, 14) is provided with an external electrode (310) that extends at least throughout the length of the tube segments and that is in contact with all tube segments. Several embodiments of the external electrode are disclosed. The external electrode is preferably connected to a node (C) midway between the lamp electrodes, to which end a capacitive divider (441, 442) is arranged in parallel with the lamp.

Abstract: A keg enveloping a container (8) for containing a beverage and means for deforming the container (8) in order to drive the beverage out of the keg (1). The container (8) comprises two substantial rigid walls (13,14), which walls are mutually connected by a flexible wall (15). The flexible wall (15) is shaped as a bellows. Said means can move the two rigid walls (13,14) towards each other, so that the distance between the two rigid walls (13,14) varies. The material of the container (8) comprises preferably a metal layer or is made of metal.

Abstract: A plurality of loads (12) such as lamps receives power through respective switches. A control circuit (16) controls the switches (14). The control circuit controls energy supplied to the loads (12) by causing the switches (14) to switch current to loads of a first half of the plurality of loads (12) on or off at one or more selectable phase points (30a,b) during each positive half of the AC cycles. The control circuit switches current to loads of a second half of the plurality of the loads (12) half an AC cycle out of phase with corresponding loads in the first half of the loads (12). In an embodiment there are least four loads (12), and the control circuit switches on lamps in the first half at two phase points (230a,b) with a temporal offset with respect to each other.

Abstract: An electric hot water kettle comprises a container (2) for containing water to be heated. In order to provide a user of the kettle with information regarding a level of water that is present inside the container (2), the kettle comprises water level indication means (10). These means (10) comprise a lighting member (20) having at least one light (21) and a float (30) which is capable of floating on water, and which is arranged in the container (2). The lighting member (20) is arranged in the float (30), so that the at least one light (21) moves along with the water surface by means of the float (30), as a result of which a most accurate indication of the water level is obtained. The at least one light (21) of the lighting member (20) is powered by a pickup coil (57) arranged in the float (30), wherein an inductive coupling between the pickup coil (57) and a coil (55) connected to the mains (52) exists.

Abstract: An apparatus for radiating an object with UV-radiation, the apparatus comprises a series arrangement of an incandescent lamp (LA1) and a gas discharge UV lamp (L2) which generates at least UV light. The series arrangement is arranged for receiving current (IP) from an AC power source (PS). A filament of the incandescent lamp (LA1) forms a ballast for the gas discharge UV lamp (LA2). A HF generator (OSC) generates a generator current (IOSC) through the gas discharge UV lamp (LA2), at least when an AC-voltage (VM) generated by the AC power source (PS) is lower than an ignition voltage of the gas discharge UV lamp (LA2), to keep the gas discharge UV lamp (LA2) ionized.

Abstract: An apparatus for radiating an object with UV-radiation, the apparatus comprises a series arrangement of an incandescent lamp (LA1) and a gas discharge UV lamp (L2) which generates at least UV light. The series arrangement is arranged for receiving current (IP) from an AC power source (PS). A controllable switching element (T1) is arranged for obtaining a lamp current (ILA1) through the incandescent lamp (LA1) to preheat the incandescent lamp (LA1) before igniting the gas discharge UV lamp (L2).

Abstract: A driver for driving a gas discharge lamp includes an inductive ballast implemented as auto-transformer having a central tap, connected between one output terminal and a first input terminal, and a triac connected between a second output terminal and a second input terminal. The central tap of the ballast is connected, via a capacitor, to the second output terminal. A control unit has a sense input for sensing the phase of an input voltage at the first input terminal, and is adapted to trigger the triac at a predetermined phase (?p) after a zero-crossing of the input voltage, the predetermined phase (?p) being in the range of ??+10° to ??+15°, ?? being the nominal phase lag of the lamp current with respect to the input voltage.

Abstract: A driver (110; 210) for driving a gas discharge lamp (1) comprises an inductive ballast (14) implemented as auto-transformer having a central tap (15), connected between one output terminal (18) and one input terminal (11), and a triac (130) connected between a second output terminal (19) and a second input terminal (12). Said central tap of the ballast is connected, via a capacitor (150), to said second output terminal (19). A control unit (220) has a sense input (226) for sensing the phase of an input voltage (VIN) at said one input terminal (11), and is adapted to trigger the triac (130) at a predetermined phase (?P) after a zero-crossing of said input voltage (VIN), said predetermined phase (?P) being in the range of ??+10° to ??+15°, ?? being the nominal phase lag of the lamp current (IL) with respect to the input voltage (VIN).

Abstract: A motor speed control for controlling the speed of an electric induction motor by modulating the amplitude and frequency of the driving voltage. When the load increases the speed control controls the speed so as to be relatively constant with respect to the frequency of the driving voltage. Preferably, the speed control controls the amplitude of the driving voltage in proportion to the square of the frequency.

Abstract: A motor speed control for controlling the speed of an electric induction motor by modulating the amplitude and frequency of the driving voltage. When the load increases the speed control controls the speed so as to be relatively constant with respect to the frequency of the driving voltage. Preferably, the speed control controls the amplitude of the driving voltage in proportion to the square of the frequency.

Abstract: A new cultivar of Sedum plant named ‘Eline’ that is characterized by its compact plant habit with strong stems that do not flop, its foliage that is dark green to grey-green and strongly tinged with grey-purple, and its flowers that are creamy white to creamy yellow in color.