HK1139452B - Flashlight for alarm systems - Google Patents

Description

Flashing lamp for alarm device

Technical Field

The invention relates to a flashing light for an alarm device, comprising a light source comprising at least one light-emitting diode and a circuit for operating the light source, which circuit comprises a feed-in device and a flashing control device.

Background

Such flashing lights are located with the hazard alarm on the alarm bus of the alarm device, for example with the fire alarm on the alarm bus of the fire alarm device. Known flashing lights have a high current draw, about ten times that of a diffused smoke alarm. It is thereby advantageous to use a flashing lamp with as little current consumption as possible for a specific effective light intensity. Obviously, the effective light intensity is not allowed to fall below a certain lower limit, because, for example, when a flashing lamp is installed in a long channel, the flashing lamp is usually seen at a flat angle, so that the light intensity perceived by the eye becomes very small.

Disclosure of Invention

The object of the invention is to provide a flashing lamp of the type mentioned at the outset which has the lowest possible current requirement and thus an improved efficiency.

The invention provides a twinkling lamp with an inductive current-reducing transformer (indektive) connected in series with a light source and a twinkling control device connected in series) To solve the above technical problems.

In the flashing lamp according to the invention the transformer current flows through the light-emitting diode, which is very important, since the current consumption is thereby reduced. A further advantage of the solution according to the invention is that the efficiency is improved by a factor of about 2 and that the current and thus the light emission of the flashing lamp remain relatively well constant over a large voltage range of about 12 to 30V.

A first preferred embodiment of the flicker lamp according to the invention is characterized in that the inductive current-reducing transformer has a control unit and the control unit is connected in series with an inductance, an inductive latching (indektionsserre) and a resistance. Preferably the resistance in combination with the control unit is such that the current for the light source is kept constant during the light emission.

Further preferred embodiments of the flashing lamp according to the invention are given in the dependent claims 4 to 10.

Drawings

The invention is explained in detail below with reference to an embodiment and a single drawing.

Fig. 1 shows a block diagram of a blinking lamp according to the invention.

Detailed Description

In the middle part of fig. 1 a light source L comprising six Light Emitting Diodes (LEDs) 1 is shown, in the upper half its feedthrough and an inductive current-reducing transformer W, and in the lower part the control electronics of the light source L, denoted flicker control means B, are shown. As shown, six light emitting diodes 1 constituting the light source L are arranged in two parallel branches, each branch having three light emitting diodes 1. This type of flashing light is commonly used in combination with an acoustic alarm, where such a combined acoustic/optical alarm is referred to herein as a "sound-Beacon", or "Blitzsummer" in german. The flashing light or Blitzsummer is preferably mounted on the ceiling and has a form similar to a fire alarm. Reference is made to european application EP07105779.8 in the name of the applicant of the present patent application, which describes, by way of example, the mechanical structure of a flashing lamp, or a suitable form and mechanical structure of a Blitzsummer. It is of course also possible to provide more than two parallel branches with light-emitting diodes 1.

The feedthrough comprises a voltage source 2 providing a voltage of, for example, 12 to 30V, and a current limiter 3 for limiting the current provided by the voltage source 2 to 3 mA. An accumulator formed by a capacitor is denoted by reference numeral 5. The inductive current-reducing transformer W comprises a control unit 4, an inductor 6, a diode 7 acting as an inductive cut-off for the inductor 6 and a resistor 8 acting as a current limiter, and the light source L is applied to the output of the inductive current-reducing transformer W. The control unit 4, the inductor 6, the diode 7 and the resistor 8 are connected in series.

The current flowing to the light source L is constantly maintained at a specific value, for example, 280mA during light emission by the resistor 8. Once this value is reached, the current supply in the inductive reduced-current transformer W is switched off (Stromzufuhr), switched back on after a few hundred milliseconds, and so on. In this way, the resistor 8, the inductor 6 and the current transformer 4 cooperate such that the current consumption of the light source L is significantly reduced and the efficiency is thereby improved by a factor of approximately 2.

The blinking control B essentially contains a microprocessor 9, which is connected, for example by means of an ASIC, to the alarm bus of the fire alarm device and from which an operating voltage of 3V and all the required alarm data are obtained, and two switches 10 for switching the light source L on and off. In the event of an alarm, the microprocessor 9 controls the two switches 10 in such a way that the light-emitting diodes 1 are switched on for 20ms and then off for 1.2s, respectively, for example. The duration of the switch-on depends on the temperature, due to the temperature dependence of the light intensity of the light-emitting diode. Thus, for example, the on-time of the light-emitting diode is 15ms at a temperature of-20 °, 20ms at +20 ° and 27ms at +70 °. This means that the pulse width increases with increasing temperature. This temperature history of the light intensity of the light-emitting diode 1 is corrected by a sensor contained in the microprocessor 9, for example a diode (not shown) for measuring the ambient temperature. By means of the two resistors between the switch 10 and the two branches with the light-emitting diodes 1, the light-emitting diodes 1 can be given a light distribution of the same brightness.

The flicker control device B controls the light emitting diode 1 according to a specific pulse waveform, which is also advantageous for reducing current consumption. The pulse shape controlling the light emitting diode 1 may also be set according to the degree of attention to be achieved. For example, the two branches with the light-emitting diodes 1 can be switched on and off alternately to give the impression of a moving light source, or the flashing lights can be flashed sequentially with a pre-flash and a main flash.

These different possibilities of controlling the light source L are particularly advantageous when the flashing lamp is mounted in a location, for example in a long aisle, where the light emitted from the light source L does not necessarily immediately cause alertness.

The described flashing lamp has the following advantages: small current consumption, improved efficiency and substantially constant light emission over a large voltage range of 12 to 30V. The flashing lamp has as large an effective light intensity as possible at a predetermined current consumption and can reliably warn the persons present there only at relatively flat angles where the flashing lamp is visible.

Claims (9)

1. A flashing lamp for an alarm device, having a light source (L) comprising at least one light emitting diode (1) and a circuit for driving the light source, which circuit has a feed-in (2) and a flashing control device (B), characterized in that the flashing lamp has an inductive current-reducing transformer (W) connected in series with the light source (L) and the flashing control device (B) in series, that the flashing control device (B) has at least one switch (10) for operating the light source (L) and a microprocessor (9) for controlling the at least one switch (10), and that the microprocessor (9) has a data communication connection to an alarm bus of the alarm device.

2. A flicker lamp as claimed in claim 1, characterized in that the inductive current-reducing transformer (W) has a control unit (4) and that the control unit is connected in series with an inductance (6), an inductive cut-off (7) and a resistance (8).

3. The flashing lamp as claimed in claim 2, wherein the resistor (8) together with the control unit (4) is such that the current for the light source (L) is kept constant during the lighting.

4. Flashing lamp according to claim 1, characterized in that the light source (L) has a plurality of light emitting diodes (1) arranged in two branches, and one switch (10) is provided per branch.

5. Flashing lamp according to claim 4, wherein the pulse shape of the pulses controlling the switch (10) is adjustable.

6. Flashing lamp according to claim 5, wherein the pulse shape of the pulses is controlled by a microprocessor (9) depending on the ambient temperature, and the microprocessor (9) is provided with a temperature sensor.

7. The flashing lamp of claim 6, wherein the width of the pulse increases as the temperature increases.

8. Flashing lamp according to any of the claims 4-7, wherein the light source (L) is controlled such that the two branches containing the light emitting diodes (1) are alternately switched on and off.

9. Flashing lamp according to any of the claims 4-7, wherein the light source (L) is controlled such that the flashing takes place sequentially in the form of a pre-flashing and a main flashing.