Gas sampling unit, for the measurement of volcanic gases, has a membrane assembly and a sieve in the gas flow to the sensor, to prevent clogging by particles

The Invention relates to a measuring device with at least one of connectable gas sensor means Gas sampling device comprising a heat and corrosion resistant Housing, a gas passage in the housing and has a communicating with the gas sensor means headspace.

For example for monitoring of volcanic activity there is a need for continuous measurement and evaluation of Parameters of removed volcanic gases, such as carbon dioxide, Radon content, sulfur content, the gas temperature, the gas pressure etc ..

Conventional Gas Meters, such as gas chromatograph, mass spectrometer, etc. are for the Use in the measurement field due to their size, the energy demand and the other supply media, such as carrier gas, limited use. It is still the problem of the relatively low sampling rates. Also no gas detection sensors are available, the prevailing environmental conditions at the measuring point can withstand. The gas sampling sites are mostly located at high altitude, where the sensors at the measuring point a corrosive rain and variable temperatures are exposed. In addition, Be the gases to be measured aggressive, especially gases of fumaroles by volcanoes.

The <patcit><text>DE 42 00 307 A1</text></patcit> describes a method for determining the flux density of from soil trespassing into the atmosphere Radon gas, which via a certain floor area a collection volume for within this bottom surface area having from the soil radon gas escaping by placing a an opening collecting on the ground while limiting the ground surface area through the opening edge formed, the activity concentration of radon in the collection determined at various time points and from the determined activity concentration values and the known area the bottom face portion the radon flux density is determined, continuously in a circulation gas from the collection is pumped, through a alpha-measuring chamber and returned to the collecting tank and determining the radon flux density on the basis of the time increase the continuously measured by alpha-measuring chamber radon activity by the measuring chamber flowing Gas is effected.

Out WO 90/13803 A1 discloses a monitoring system Known for gas analysis, for example for the detection of environmental pollution, the a test module with a gas-permeable tube wall, which serves as a membrane for collecting the gas, if at least one sample of the gas to be measured and the tube wall available. The material and the structure of the tube are while such a nature that the membrane diffusion resistance low enough is to allow the membrane to a gas flow through the wall, and high enough compared with the resistance outside the tube wall, around the outer resistance negligible to make so that the membrane diffusion resistance of the tube wall substantially all of the diffusion resistance to the gas flow through the tube wall represents.

furthermore describes the <patcit><text>DE 196 10 402 A1</text></patcit> a soil gas collection system using a gas-permeable but waterproof collection tube with segmentation the horizon related sampling over and groundwater, consisting from a gas-permeable, stiffened internally against collapsing and outside against damage protected Gas-collection hose, Absperrpfropfen inside and shut-rings outside and a central tube with gas-extraction pipe or gas-sampling lines inside or outside postponed or as short Arrivals.

The <patcit><text>US 4350051</text></patcit> describes a probe for Sampling of underground soil gas, comprising an elongate Shaft, which is drivable into the ground and a passage for including removal of underground soil gas samples, a probe tip assembly with a sealing surface, which is attached to a first end of the passage, and Sealing means disposed in the passage, and trigger means at a second end of the passage for selectively triggering the Sealing means, so that they act with the sealing surface.

In Francis P., A. Maciejewski, Oppenheimer C. and C. Chaffin (1996) New methods make volcanology research less hazarodous. EOS, Transactions on the Geophysical Union 77, 41. 193, 396-397, and in De Natale P., Gianfrani L. and De Natale G. (2001) Optical methods for monitoring of volcanoes: techniques and new perspectives. Jornal of Volcanology and Geothermal Research 109: 1-3. 235-245 are optical method of spectral components such as sulfur dioxide (SO2) and hydrogen chloride (HCL) determined in the gas sample. To this end, is at least one infrared light source and at least one spectrometer positioned so that the spectrum of the pressing by a gas stream Infrared light beam can be determined. The optical method require a clear view, often by considerable cloudiness or restricted by haze is. Among the means available device relatively big and heavy and consume a relatively large amount &lt;?page 3?&gt;Energy.

In Toutain J.-P., Baubron J.-P., Le Bronec J. Allard P., P. Briole, Marty B., G. Miele, Tedesco D. and G. Luongo (1992) Continuous monitoring of distal gas emanations at Vulcano, southern Italy. Bull Volcanol 147-155 and in Shimoike Y. and Notsu K. (2000) Continuous chemical monitoring of volcanic gas in Izu Oshima volcano, Japan. Journal of Volcanology and Geothermal Research 101, 211-221 are chemical monitoring procedures described in which analyzes the gas components of water be that at a water fountain or from a hole edge emerges from volcanoes. The environmental impact of these measuring points is less than at the measuring points of the fumaroles in the crater. In addition, the water points are more accessible than a volcanic crater.

Although a connection between the gas composition in the analyzed Water mixture and the Fumarolengasen is, allows the chemical monitoring No direct measurement of the fumarole.

In Room M. and Erzinger J. (1998) Geochemical monitoring on Merapi Volcano, Indonesia. Communication German Geophysical Society e. V., DGG Special Issue III / 98 ISSN number. 0947-1944. 89-92 and Room M., J. Erzinger and Sulistiyo Y. (2000) Continuous Chromatographic Gas Measurements on Merapi Volcano, Indonesia. releases German Geopysikalische Society e. V., DGG Special Volume IV / 2000. ISSN number. 0947-1944, 87-91 is measuring Fumarolengasen using gas chromatography equipment described, wherein the gas samples via hose lines and water traps to reduce the water vapor content of the gas samples are directed to gas sensor means. The gas sensor means powered by solar energy, the continuous power supply is ensured by a rechargeable battery. The measurement data is a Radio interface consists of a modem and a mobile radio device to a remote analysis center received. The measuring device can the radio interface to be remotely controlled from the evaluation center. The measuring rate is disadvantageous due to the gas chromatograph used and radon alpha scintillometer as a gas sensor means relatively low. So are the concentration of water H2O, CO2 nitrogen, sulfur dioxide SO2 and hydrogen sulfide H2S every 35 minutes and the radon concentrations and the fumarole temperature measured every 70 minutes.

In Faber E., S. Inguaggiato, Garzon-Valencia G. and D. Seidl (1998) Continuous Gas Measurements at Volcanic fumaroles. Messages German Geophysical Society e. V. DGG Special Volume III / 1998th ISSN number. 0947-1944, 83-87 is a similar described measuring device, wherein the gas sampling probes in Fumaroles of a volcano are introduced. The gas sampling probes hollow steel lances with gas passage openings to which a stainless steel tubing connected. The stainless steel tubing is at least an extracting agent in the form of a water trap to reduce out of the water vapor content of the extracted gas sample and a Teflon tubing and polyethylene tubing and a Gas pump gas sensors such as mass spectrometers, radon measuring equipment, gas chromatograph and Mulitsensoren for detecting the concentration of various Gas components passed. The measurement data is via a radio transmission means telemetrically transmitted to a remotely located from the measuring point evaluation. With Using the wireless transmission means is also a remote control of the gas sensing means and gas sample pump possible by the evaluation.

The there is problem in the described conventional gas measurement method that the gas sampling devices by extreme weather conditions are exposed to corrosion and high temperatures. To the particular leads the high sulfur content in the gas samples to the fact that the tubing plug and the gas sensors are destroyed.

task the invention was therefore to provide an improved measuring device for gas samples create, with the reliable monitoring of Concentration of various constituents in the gas samples with high Measuring rates even under extreme environmental conditions is possible.

These Object is achieved by a measuring device with the features of Patentenaspruches 1 dissolved.

It has been shown that interfering Deposits in the gas sampling device and in the hose line occur and these deposits must be avoided. there it has been found that by using a diaphragm, the Deposits were significantly reduced, the gas samples, however, still arrive by diffusion through the membrane into the gas chamber.

Of the Gas chamber of the gas sampling device has a gas sample inlet and a Gaspobenauslass to a sample taken by the Gasprobenauslass Gas sample to the gas sample measurement with the gas sensor means again through the gas sample inlet into the gas space zurückzulei&lt;?page 4?&gt;th. The removed Gas samples then pass by diffusion through at least one Diaphragm of the diaphragm assembly into the gas chamber and the from there over Gasprobenauslass and gas sensor means back through the gas sample inlet in the headspace pumped. In the measuring device is then established by short period of time an equilibrium with the gas in the vicinity of the gas sampling device and it will only take a net gas flow of non-condensable Components through the membrane assembly when, the composition the gas to be measured changes. hereby the occurrence of debris can be further reduced.

The at least one gas sampling device is provided with a respective Tubing connected to associated gas sensor means. It should the tubing in the region of the gas sampling device as well as the housing and membrane assembly hitz his e- and corrosion resistant. Preferably , the housing, the membrane arrangement and / or the tubing of Teflon.

The Hose line with a flushing device connected to the tubing at intervals of a detergent to flush, with the aid of a detergent pump is pumped through the tubing. For purging the gas passage and the Membrane order is the flushing device communicatively connected to the gas sampling device. On this way Deposits in the measuring device regularly eliminated remotely will.

In the tubing is in a known manner at least one extracting agent, For example, a water trap, connected to the water vapor content in the extracted gas sample to reduce.

The Gas sensor means are preferably gas sensors for the detection of Carbon dioxide levels, the radon content, the Schefeldioxidgehalts, the gas temperature and / or the gas pressure.

It is advantageous if the measuring device position determining means, notably satellite-borne Detection means for detecting the spatial position of the measuring device Has. The positioning means, such as global positioning systems (GPS), this will be at the gas sampling locations or in the field can set up the gas sensor means and electrically in the system be integrated to the measuring device.

furthermore preferably wireless transmission means to transfer of the measured data for the withdrawn gas sample to a central Messdatenauswertereinheit and for transmitting Control data from the central Datenauswertereinheit to the measuring device provided. In this way, a continuous remote monitoring possible.

The Measuring device further has preferably more than one Fieldbus interconnected control positions, the each gas sensor means an associated gas sampling device are connected. For each gas sampling device and associated measurement point can Thus, in a simple manner the associated gas sensor means to a common control unit can be clamped, without having a complicated Wiring and an opening the housing of the Measuring instruments used, in particular the gas sensor means necessary becomes.

The Radio transmission means are also preferably clamped to the fieldbus. moreover can the control units each with independent Energieversor movement forward, be especially fed solar supplies. Moreover, it is advantageous if the analog / digital converter between the gas sensor means and the control units are clamped. With the aid of the control units a variably interconnectable monitoring system is thus realized.

The Measuring device is described with reference to the accompanying drawings explained in more detail. It show:

<figref idrefs="S17">1</figref> Cross-sectional view a gas sampling device with the membrane;

<figref idrefs="S18">2</figref> Cross-sectional view a second embodiment a gas sampling device with double membrane;

<figref idrefs="S18">3</figref> Top view the gas sampling device according to <figref idrefs="S18">2</figref>

<figref idrefs="S19">4</figref> measuring device with gas sampling device, extraction means and the gas sensor means and a flushing device;

<figref idrefs="S20">5</figref> measuring device with a gas sampling device and hose assemblies for reciprocating and repatriation of gas samples;

<figref idrefs="S21">6</figref> block diagram a measurement system with more than a fieldbus interconnected measuring equipment for several Measuring points.

The <figref idrefs="S17">1</figref> leaves a Gas sampling device <figref>1</figref> for taking gas samples G in &lt;?page 5?&gt;identify cross-section. The gas sampling device<figref>1</figref> Has a heat- and corrosion-resistant housing <figref>2</figref> preferably of teflon, which with a support <figref>3</figref> to a holding rod be mounted and positioned at a gas sampling point can.

The Gas sample G is a gas-permeable support and protection panel <figref>4</figref>. which forms a gas passage, in a gas chamber <figref>5</figref> passed. Between the support and protection panel <figref>4</figref> and the gas space <figref>5</figref> is a vapor-permeable membrane <figref>6</figref> and a screen plate <figref>7</figref> for sorting disposed of fines of the vapor stream. The gas space<figref>5</figref> is with a Gasprobenauslass <figref>8th</figref> coupled, to which a hose line clamped to derive the gas samples G to gas sensor means can be.

By which is preferably made of Teflon membrane are particularly Sulphur deposits in the gas sample G of the gas chamber <figref>5</figref>. the connected thereto hose lines and the gas sensor means kept.

The <figref idrefs="S18">2</figref> leaves a another embodiment a gas sampling device <figref>1</figref> with a cylindrical housing <figref>2</figref> recognize. The diaphragm assembly is a so-called double membrane with each a membrane <figref>6a</figref>. <figref>6b</figref> right and left of the headspace <figref>5</figref> executed.

The gas flows by gas passages <figref>9</figref> in the outer cylindrical space <figref>10</figref> of housing <figref>2</figref> inside, of the interior gas space <figref>5</figref> surrounds.

In the interior gas space <figref>5</figref> At least one hose <figref>11</figref> performed, the communicates with the gas sensor means.

The <figref idrefs="S18">3</figref> leaves the Gas sampling device <figref>1</figref> from the <figref idrefs="S18">2</figref> in see the plan view. The interior gas space<figref>5</figref> is a first hose line <figref>11</figref> for discharging the gas sample G and another hose <figref>12</figref> for returning the gas samples G in the inner gas chamber <figref>5</figref> provided.

The Gas sampling device <figref>1</figref> can thus as a closed System will be integrated into a measuring device, wherein a is Balance between the gas sample G inside the measuring device to the gas in the vicinity of the gas sampling device <figref>1</figref> adjusts.

The Integration of the gas sampling devices described above in a measurement device is made of <figref idrefs="S19">4</figref> more clear, showing a measuring device as a block diagram. The gas sampling device<figref>1</figref> is a fumarole of a volcano, where it is a holding rod <figref>13</figref> kept. The gas sampling device <figref>1</figref> is a hose line <figref>11</figref> coupled, the gas samples G through extracting agent <figref>14a</figref>. <figref>14b</figref>. <figref>14c</figref> Gas sensor means <figref>15a</figref>. <figref>15b</figref> to to guide. The extraction agent<figref>14a</figref>. <figref>14b</figref>. <figref>14c</figref> are Water traps with which the water vapor content of the gas samples G is reduced. For this purpose, a hose section of tubing<figref>11</figref> perpendicular and the lower end in a water tank to prevent a Gas leakage dipped. By condensation of the extracted gas sample G flows Condensation in the water tank.

As Gas sensor means <figref>15</figref> can known gas chromatograph, mass spectrometer, radon sensors or other sensors certain gas components and / or sensors for detecting the multi- Concentration of various components of the gas sample used G will.

furthermore is a corrosion and heat resistant Thermometer <figref>16</figref>. preferably a thermocouple for determining the gas temperatures and a pressure measuring device <figref>17</figref> for determining the gas pressure P incorporated into the fumarole.

According to the invention is a flushing <figref>18</figref> available, applied to the gas sampling device <figref>1</figref> or the hose line <figref>11</figref> With a flushing line <figref>19</figref> affiliated is. The flushing device<figref>18</figref> Has a pump / valve assembly <figref>20</figref> to detergent <figref>21</figref> from a detergent dispenser <figref>22</figref> by the gas sampling device <figref>1</figref> and the tubing <figref>11</figref> to pump. In this way, Deposits by douching in flushing intervals be eliminated.

The <figref idrefs="S20">5</figref> leaves a another embodiment Detection of the measuring device as a block diagram. This has the Gas sampling device <figref>1</figref> a gas sample inlet and a Gasprobenauslass accordance with the <figref idrefs="S18">3</figref> Embodiment shown, wherein a first hose line <figref>11</figref> for deriving a Gas sample G on extracting agent <figref>14</figref> to the gas sensors <figref>15a</figref>. <figref>15b</figref> at a Gasprobenauslass <figref>8th</figref> is clamped. The with the gas sensors<figref>15</figref> analyzed Gas sample G is by means of a gas pump <figref>23</figref> over a additional hose <figref>12</figref> through the gas sample inlet of Gas sampling device <figref>1</figref> in the inner gas chamber <figref>5</figref> returned.

The taken from the fumarole gas sample G passes by diffusion through the membrane <figref>6</figref> in the inner gas chamber <figref>5</figref> of the Gas sampling device <figref>1</figref>, The closed System arises in the measuring device after a short time Balance of the hose lines <figref>11</figref> and <figref>12</figref> located Sample gas G to the gas in the vicinity of the gas sampling device <figref>1</figref>&lt;?page 6?&gt;on, this means with Fumarolengasen. This will only take a net gas flow the non-condensable components through the membranes <figref>6</figref>, if the composition of the gas to be analyzed changes. Thereby the measuring device is considerably less aggressive influences of exposed to gas to be measured and be harmful deposits reduced.

The <figref idrefs="S21">6</figref> leaves a System with a plurality of gas sampling devices <figref>1a</figref>. <figref>1b</figref>. <figref>1c</figref> recognize, described respectively in the above manner via hose lines at gas sensor means <figref>15</figref> clamped are.

The Gas sensor means <figref>15</figref> are in turn connected to analog-to-digital converters <figref>24</figref> connected, each connected to a control means <figref>25</figref> are clamped. furthermore is a clock <figref>26</figref> provided for counting the measurement rate and the gas sensor means <figref>15</figref> and the control units <figref>25</figref> connected.

The Power is supplied with a self-sufficient power supply unit <figref>27</figref> With solar panel <figref>28</figref> and storage batteries <figref>29</figref>, alternative can also Energieversor supply by utilizing the gas pressure or the thermal energy take place at the measurement site.

The Control means are to radio transmission means <figref>30</figref> connected, to the measured data by telemetry to a remote analysis unit transferred to. For the the control units <figref>25</figref> in such a way that a remote control of the measuring device from an external evaluation unit via the Radio transmission means <figref>30</figref> is made possible.

The control units <figref>25</figref> are connected via a digital fieldbus <figref>31</figref> together coupled. The individual components of the measuring device are in this case adapted to this with robust connectivity systems simply electrically can be connected together. The fieldbus <figref>31</figref> has the advantage that extensions and supplements the measuring device without interfering with the existing components can take place.

The Temperature measurement is preferably carried out with a thermocouple, is that embedded in a Teflon tube and thus protected against corrosion. The pressure is measured with a pressure sensor, which at one of be called arranged region of the distal end of a fumarole Teflon hose is. The other open end of the Teflon tube is against the direction the effluent Gas directed.

The Measuring device is preferably for measuring Fumarolengasen Suitable of volcanoes, but can also be used to measure gases in other Environments, such as for the monitoring of soil gases, or Gases in the atmosphere be used.

The Measuring device further has preferably position determining means, notably satellite-borne Locating means for the global positioning system GPS, so that the measured parameters of the extracted gas sample G in a central Evaluating a spatial position can be assigned. For a portable measuring device can thus a simple way of mapping the measurement data, and done creating isoline maps.