DE29511719U1 - Device for dehumidifying masonry - Google Patents

Description

Wall dehumidification

The invention relates to a device according to the preamble of claim 1.

Such a device is known from European patent application 0 395 085 A1. In this known device, a high-frequency oscillation in the range of about 141 KHz plus/minus 4 KHz is generated by stimulating a resonator comprising a coil and a capacitor with a low-frequency pulse train signal, so that after each excitation of the resonator by a pulse train signal, a high-frequency, damped oscillation occurs, the amplitude of which drops to a value of less than 10% of the maximum amplitude of the oscillation during the duration of half a period of the pulse train signal. The electromagnetic waves emitted by the coil act on masonry without contact and cause it to be dehumidified.

Since the frequency of the high-frequency waves emitted by the coil of approx. 141 KHz is determined from the parameters

of the coil and the capacitor in the resonator, which is excited by a pulse to oscillate at its natural frequency, they must be adjusted. For this purpose, the capacitor is designed as a variable capacitor. However, such an adjustment is relatively difficult, since the fundamental frequency of a damped oscillation can only be measured with sufficient precision with relatively high effort. However, the most precise adjustment possible is necessary, since a good approximation to 141 KHz requires a significant optimization of the dehumidification effect. In addition, the resonance frequency of the oscillating circuit is not sufficiently constant due to influences on the air coil. In particular, metal parts in the vicinity of the air coil, but to a much lesser extent also changes in its inductance due to fluctuations in air pressure or humidity, cause considerable disturbances in the radiated electromagnetic field. The steepness of the damping of the oscillation can also be influenced by electrically conductive parts in the area of the coil.

Based on this, the object of the present invention is to create an uncomplicated and inexpensive device that can be used as simply, reliably and reproducibly as possible for generating electromagnetic fields suitable for dehumidifying a wall. This object is solved by the characterizing part of claim 1.

The device according to the invention enables the generation of alternating electromagnetic fields with a very precisely defined frequency. Influences on the high frequency of the alternating field or, in particular, in the case of sequences of wave trains that are dampened with an envelope curve, changes in the shape of the curve due to environmental influences in the area of the coil, such as electrically conductive metal parts, are significantly reduced when the device is designed according to the invention. Adjustment of the device when it is put into operation is not necessary. In addition, the device according to the invention can be implemented using simple and inexpensive means. In particular, due to the frequency-stable structure, it can be designed with good EMC compatibility (electromagnetic compatibility).

Particularly advantageous embodiments of the invention emerge from the subclaims. The device can preferably be supplied with its supply voltage via an EMC-compatible standard power supply unit, since the entire device can thus be designed relatively easily to be EMC-compatible.

A frequency-stable oscillator is preferably used as the oscillator in order to avoid fluctuations in the frequency of the radiated electromagnetic fields.

It is particularly useful to design the oscillator with a phase-locked loop (=PLL) circuit, which allows for reliable, simple and cost-effective implementation.

The phase-locked loop circuit preferably includes a voltage-controlled oscillator (=voltage-controlled oscillator = VCO) which is connected on the output side to a frequency divider, which in turn is connected on the output side to a phase comparison for controlling the voltage-controlled oscillator. A single or multiple mains voltage frequency is preferably used as the reference frequency of the oscillator in order to achieve the simplest possible structure.

The coil is suitably designed as an air coil because the permeability of air results in a suitable coil size when the coil is designed to radiate high-frequency electromagnetic fields.

It is advantageous to have a modulator connected downstream of the oscillator, through which sequences of wave trains can be generated, each with an envelope of lower frequency than the high-frequency oscillations, since it has been shown that a combination of high-frequency electromagnetic oscillations with low-frequency

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Vibrations, for example in the range of the fluctuation frequency of the earth's magnetic field of 7 to 15 Hz or similar have a positive influence on the dehumidification of the masonry. The envelope curve can be conveniently generated by a differentiator connected to the input side of a low-frequency square-wave alternating voltage, in particular consisting of a capacitor and a resistor, which results in a very simple structure.

It can also be advantageous if the air coil can also be subjected to a low-frequency voltage in order to generate an alternating electromagnetic field with high-frequency and low-frequency components.

Further features and advantages emerge from the description of an embodiment based on the drawing. It shows:

Figure 1 is a block diagram of an embodiment of a device according to the invention for dehumidifying masonry and

Figure 2 shows another embodiment.

Figure 1 shows an electronic circuit for generating a high-frequency voltage U, which is applied to a coil L which generates an alternating electromagnetic field E that acts on a wall 1 spaced from the coil L, which is thereby dehumidified.

The circuit is supplied with supply voltage and a low-frequency signal S1 from a power supply unit 2, which serves as a reference signal for the phase comparison 3. The phase comparison 3 controls the voltage control oscillator (=VCO) 6 via a control signal S2. The VCO generates an extremely frequency-stable output signal S3, preferably at 141 KHz as precisely as possible. This high-frequency signal S3 is applied to the coil L, which generates a corresponding alternating electromagnetic field. In addition, the signal S3 is passed on to a frequency divider 4, which converts the high-frequency signal into a low-frequency signal S4, for example using a digital counter circuit with a frequency division factor. Here, a low-frequency signal S4 is generated with the high-frequency signal S3 of 141 KHz with a frequency division factor of 1/1410 achieved by wiring a digital counter. The phase comparison 3 is carried out with this signal S4 and the signal Sl, which here also has 100 Hz, and the result of the phase comparison is used as signal S3 to control the VCO 6.

In the embodiment shown, the oscillator 5 comprises a phase comparison 3, a VCO 6 and also a frequency divider 4 for generating a signal of the same frequency as the reference frequency. The phase comparison and VCO components of the oscillator can be implemented on a standard module, for example.

Figure 2 shows a further embodiment of the invention, which, in accordance with Figure 1, comprises a power supply unit 2 and an oscillator 5 with a phase comparison 3, a frequency divider 4 and a VCO 6. In addition, however, in the embodiment shown in Figure 2, the high-frequency signal S3 at 141 KHz is modulated in a modulation unit connected downstream of the oscillator. This creates sequences of wave trains, each with an envelope of a lower frequency than the high-frequency signal S3. For this purpose, the signal S4, which is approximately rectangular here, is passed through a differentiator, here in the form of an RC element, so that the signal S5 is generated in the form of individual pulses that decay exponentially. This signal S5 is used to modulate the high-frequency signal S3 in the modulator 7, so that a signal S6 is produced, which has high-frequency oscillations with envelopes in the form of the exponentially decaying individual pulses S5. The coil L is supplied with this signal S6. The modulation of the high-frequency signal with sequences of exponentially decaying individual wave trains results in a

• *

Better electromagnetic compatibility compared to high-frequency continuous signals.

Furthermore, to optimize the dehumidification effect, the air coil L can additionally be supplied with a low-frequency signal, here a signal of 50 Hz generated by a frequency divider 8, via a switch 10.

The invention allows the very efficient dehumidification of masonry, in particular due to the high frequency stability achieved through the use of an oscillator with a good efficiency.

Claims (1)

Expectations Device for dehumidifying masonry with a coil (L) for the radiation of high-frequency electromagnetic fields, characterized in that the coil (L) is preceded by an oscillator (5) by which a high-frequency alternating voltage (U) can be generated, with which the coil (L) can be acted upon. 2. Device according to claim 1, characterized in that the device can be supplied with a supply voltage via an EMC-compatible standard power supply unit (2). 3. Device according to one of the preceding claims, characterized in that the oscillator (5) is frequency stable. 4. Device according to one of the preceding claims, characterized in that the *♦·*♦ Oscillator (5) is designed as a phase-locked loop (=PLL) circuit. Device according to claim 4, characterized in that the phase-locked loop circuit comprises a voltage-controlled oscillator (6) which is connected on the output side (S3) to a frequency divider (4), which in turn is connected on the output side (S4) to a phase comparison (3) for controlling the voltage-controlled oscillator (6). 6. Device according to claim 5, characterized in that a single or multiple mains voltage frequency can be used as the reference frequency (Sl) of the oscillator (5). 7. Device according to one of the preceding claims, characterized in that the coil (L) is designed as an air coil. 8. Device according to one of the preceding claims, characterized in that the oscillator (5) is followed by a modulator (7) through which sequences of wave trains (S6) each with an envelope of lower frequency than · •·♦ ·*» the high-frequency oscillations (S3) can be generated. 9. Device according to claim 8, characterized in that the envelope curve can be generated by a differentiator (9) connected on the input side to a low-frequency square-wave alternating voltage. 10. Device according to claim 9, characterized in that the differentiator (9) comprises a capacitor and a resistor. 11. Device according to one of the preceding claims, characterized in that the air coil (L) can additionally be supplied with a low-frequency voltage via a switch (10).