EP1307683B1 - Carbon dioxide fire extinguishing device - Google Patents

Description

The present invention relates to a carbon dioxide fire extinguishing device.

State of the art

For fire extinguishing devices with gaseous extinguishing media is prescribed that the pressure vessel in which the extinguishing medium under pressure stored, is checked for gas losses. For carbon dioxide pressure bottles It must be ensured that a gas loss of more than 10% the filling weight is determined safely. Transportable carbon dioxide fire extinguisher are calibrated during their periodic check by means of a Weighed the balance. Between two checks, a gas loss remains unnoticed. In stationary carbon dioxide fire extinguishing systems hang the Carbon dioxide pressure cylinders individually in a weighing device, so that the Weight of each carbon dioxide pressure bottle continuously monitored becomes. If a specified weight is exceeded, an alarm is triggered. Such weighing devices for hanging the carbon dioxide pressure bottles the stationary fire extinguishers increase the cost considerably. You need to also be calibrated at regular intervals.

Until now, there was no satisfactory alternative to weighing the Carbon dioxide Dnrckflaschen.

Pressure controls are for detecting a gas leak from a Carbon dioxide pressure bottle completely unsuitable there, with a usual Ratio of 1: 1.50 (i.e., a fill weight of 0.666 kg of carbon dioxide per Liter of bottle volume), below a temperature of 27 ° C a loss of gas of 10% caused no significant pressure drop in the bottle anymore (at a fill ratio of 1: 1.34, i. a filling weight of 0.746 kg of carbon dioxide per liter of bottle volume, this is the lower temperature limit even about 22 ° C). In addition, the pressure in the carbon dioxide pressure bottle strongly dependent on temperature.

Even level gauge with float have, at least at Fire extinguishing devices, not as an alternative to weighing carbon dioxide pressure vessels can enforce. A valve with an integrated level gauge with float, as e.g. from the patent US-A-4,580,450 to a carbon dioxide pressure bottle is known in carbon dioxide fire extinguishing systems not usable because the accommodation of the linkage the level gauge in the valve base takes up a lot of space and thereby the inlet hole for the gas in the valve base will be relatively small got to. In this context, it is indeed noted that carbon dioxide pressure bottles for stationary carbon dioxide fire extinguishing devices in only a female thread W 28.8 x 1/14 "according to DIN 477 to have. In this internal thread a valve base must be screwed in, the one inlet hole for the extinguishing agent of at least 12 mm in diameter should allow the carbon dioxide after triggering the fire extinguishing device, With low pressure loss can flow into the valve.

From US-A-5,701,932, WHICH is considered the closest prior art, is for gas bottles with high purity Gases, a gas cylinder valve with a built-in capacitive level gauge as an alternative to a mechanical level measurement with Swimmers known. The capacitive type described in US-A-5,701,932 Level measurement is based on the principle that the liquid phase a gas has a much higher dielectric constant than the gaseous one Phase, so that a sinking of the liquid level in the pressure bottle reflected in a reduction in the capacity of the probe. This measuring principle thus presupposes that the measurement at a given ambient temperature which ensures that there are two separate There are phases in the pressure bottle, and that the liquid level in the Pressure bottle decreases if gas is removed from the pressure cylinder. This is however, in contrast to the application described in US-A-5,701,932 for high-purity gases, for a carbon dioxide pressure bottle for the fire extinguishing area not always the case. In fact, be in fire extinguishing devices Carbon dioxide pressure bottles u.a. in machine rooms for property protection used, readily reaching ambient temperatures above 40 ° C. can be. Now take at a filling ratio of the carbon dioxide pressure bottle from 1: 1.50 (i.e., 0.666 kg of carbon dioxide per liter of bottle volume), the liquid phase of the carbon dioxide already from a temperature of 27.2 ° C, the entire bottle volume, so that above this temperature a loss of gas is no longer necessarily a change in the liquid level in the pressure bottle causes. In addition, the critical temperature of carbon dioxide, from which the carbon dioxide forms a supercritical fluid by anyway no difference between a gaseous and a liquid phase, even at 31 ° C.

Furthermore, the valve with the capacitive level measuring device from US-A-5,701,932 note that it is also fluidic Do not reason for carbon dioxide pressure bottles in fire extinguishers suitable. In fact, in a valve base with a W 28.8 x 1/14 "screw thread the installation of the capacitive probe takes up so much space that there is no room left for an inlet hole of at least 12 mm diameter for the carbon dioxide quenching gas remains. To have enough space for one To win such 12 mm inlet bore in the valve base, one could of course the diameter of the capacitive probe still smaller. However, one would have to stability problems of the probe with in Take a purchase, which is not responsible for a security-related element are.

Object of the invention

The present invention is therefore based on the object in one Carbon dioxide fire extinguisher the carbon dioxide pressure vessel, both at low as well as high ambient temperatures, without weighing Reliable to control gas losses. This object is achieved according to the invention achieved by a device according to claim 1.

General description of the invention

In a carbon dioxide fire extinguishing device according to the invention is the Detecting a loss of gas from the carbon dioxide pressure vessel a Capacitive measuring device used for a temperature range is calibrated below and above the critical temperature of the carbon dioxide. In other words, the present invention is based on the surprising Acknowledgment that a capacitive measuring device not only in a known way and Can measure changes in fluid level in the pressure vessel, but also above the critical temperature of the carbon dioxide, i. if there is no more physical difference between the gaseous and the liquid phase of the carbon dioxide gives a gas loss from the Pressure vessels are assigned a measurable capacity change clearly can. In this way, a simple solution for determining a Gas loss from a carbon dioxide pressure vessel of a fire extinguisher provided even at high ambient temperatures (i.e. Temperatures over 30 ° C) can be used and a complex weighing of Makes pressure vessel superfluous.

Such a capacitive measuring device preferably comprises: a capacitive Measuring probe which extends over the entire height of the pressure vessel, a measuring module for measuring the capacitance of the capacitive measuring probe, a Microprocessor for processing the measured capacitance measurements, a measured capacitance change a corresponding gas loss assigns, as well as means for generating an alarm message if that of the microprocessor determined gas loss exceeds a predetermined value.

The calibration is preferably done electronically, e.g. a temperature sensor and a memory with calibration values for a temperature range used below and above the critical temperature of the carbon dioxide become. The microprocessor accesses the calibration values in a temperature-dependent manner Memory back to a measured capacitance change a corresponding Allocate gas loss. If the calculated gas loss is a exceeds predetermined value, the microprocessor generates an alarm message.

Such a device is ideal for controlling the gas content of carbon dioxide pressure cylinders, both at high and at low levels Ambient temperatures. It is therefore particularly suitable for use in Carbon dioxide fire extinguishing devices suitable where the ambient temperature between -20 ° C and + 60 ° C can lie.

Thus, this device also easily in a carbon dioxide fire extinguishing device in combination with a carbon dioxide pressure bottle is usable, the present invention has additionally solved the problem that Capacitive probe so cheap by the tight bottleneck in the Introduce carbon dioxide pressure bottle that the outflow resistance of the Extinguishing gas from the pressure bottle is hardly enlarged. For this purpose, the present Invention an outlet valve for a carbon dioxide pressure bottle with a integrated capacitive probe, wherein a first measuring electrode is formed by a riser, which opens into the valve base, and a second measuring electrode is formed by an electrode tube, which surrounds the riser with an intermediate gap over its entire length. By this exhaust valve finally results in a simple, reliable and cost effective way transportable carbon dioxide fire extinguisher easier and more often to check for gas loss, or elaborate weighing devices for carbon dioxide pressure cylinders in stationary carbon dioxide fire extinguishing devices to avoid. In particular, it should be emphasized that such exhaust valve with probe about the same outflow resistance may be like a flow-optimized outlet valve without a measuring probe. This is where the capacitive measuring probe stands, in which the riser pipe an inner measuring electrode is formed, even with large pressure bottles by a excellent stability.

There are also versions of this valve presented in which the electrical connection with the capacitive probe on a particular space-saving and trouble-free way is solved.

In a first embodiment, an insulating sleeve surrounds the first end of the Riser in the inlet bore of the valve base and it isolated electrically from the conductive valve base. In the inlet hole of the valve base is this first end of the riser then with a contact element from the conductive valve socket is electrically isolated, electrically in contact. The outer Electrode tube, however, is electrically connected to the conductive valve base in Contact and is electrically connected via the latter. The first end of the Riser advantageously has an annular end face as a contact surface for the insulated contact element on, allowing to produce a reliable electrical connection between the insulated contact element and the Riser, the latter only in the axial direction of the contact element in the Inlet hole of the valve base must be pressed.

An insulated contact element suitable for this first embodiment comprises advantageously a contact ring with approximately the same inner and outer diameter as the annular contact surface of the riser, and a Insulating ring with larger outer diameter than the contact ring. This Insulating ring lies with an end face on a shoulder surface in the inlet bore and has in the other end face a recess into which the Contact ring is fitted. In this embodiment, a large area, ensures trouble-free contact between riser and contact element, while reliably preventing an electrical short circuit.

The valve base advantageously has a connection channel in this first embodiment on, which forms an opening in the aforementioned shoulder surface, at which the insulating ring rests in the inlet bore. The insulating ring then has in turn an annular groove in the end face, which on this shoulder surface rests, with the opening of the channel in the shoulder surface in this Ring groove opens, and a perforation of the insulating ring from the Ring groove extends to the contact ring. In this version is then an isolated Connecting wire with a first end firmly connected to the contact ring and through the through-hole and the annular groove of the insulating ring in the connection channel introduced. The annular groove prevents this, that the connecting wire is sheared off, if the contact element is twisted in the inlet bore.

The second end of the aforesaid lead wire is fixed to one of connected externally accessible connection element, the latter sealed and electrically isolated is inserted into a bore of the valve base. The conductive valve base makes electrical contact with the outer electrode tube ago. The electrical contact between the outer electrode tube and the valve base can then via an annular end face of the outer Electrode tube are produced, which are connected to an annular end face of the Valve socket is pressed.

In this first embodiment, one end of the insulating sleeve preferably protrudes from the bore of the valve base and serves to attach the outer electrode tube. In an advantageous embodiment, this electrode tube e.g. screwed onto this end of the insulating sleeve, that its annular end face fixed to the annular end face of the valve base is pressed. In this case, the insulating sleeve thus fulfills the function of an electrical Isolator between riser and valve base, an insulating Spacer between riser and outer electrode tube and a Fixing and pressing device for the outer electrode tube. By This multifunctional sleeve will require a minimum of parts for installation both measuring electrodes needed. The insulating sleeve can continue to be an electrical have conductive outer wall, over which the valve base and the outer Electrode tube are electrically connected together. This will be the electrical contact between valve base and outer electrode tube on improved.

In an alternative embodiment of the measuring electrode is the riser with screwed its upper end into the inlet bore of the valve base. An upper insulating sleeve is pushed onto the upper end of the riser. A lower mounting sleeve is placed on the lower end of the riser unscrewed, with the screwed mounting sleeve the outer Pressing the electrode tube axially against the upper insulating sleeve. The upper insulation sleeve This is advantageous against an end face of the valve socket pressed. A preferred embodiment of the lower mounting sleeve comprises a metallic Kemkörper the screwed onto the lower end of the riser is and an insulator between the metallic core body and the outer electrode tube is arranged.

Description based on the figures

Fig.1:

ein Blockschema das einen beispielhaften Aufbau einer erfindungsgemäßen Kohlendioxid-Feuerlöschvoriichtung;

Fig.2:

einen Längsschnitt durch ein Auslassventil einer Kohlendioxid-Feuerlöschvorrichtung mit integrierter Vorrichtung zum Feststellen eines Gasverlustes aus der angeschlossenen Kohlendioxid-Druckflasche, wobei eine erste Ausgestaltung eines Steigrohrs gezeigt ist, das als kapazitive Messsonde ausgebildet ist;

Fig.3:

eine Vergrößerung des eingerahmten Details I aus Fig. 2; und

Fig.4:

eine Vergrößerung des eingerahmten Details II aus Fig. 2.

Fig.5:

einen Längsschnitt durch eine weitere Ausgestaltung eines Steigrohrs das als kapazitive Messsonde ausgebildet ist; und

Fig.6:

einen Längsschnitt nach Schnittlinie 6-6 durch das Steigrohr der Fig. 5.

An embodiment of the invention will now be described with reference to the accompanying drawings. Show it:

Fig.1:

a block diagram illustrating an exemplary structure of a carbon dioxide fire extinguishing Vorparichtung invention;

Figure 2:

a longitudinal section through an exhaust valve of a carbon dioxide fire extinguishing device with integrated device for detecting a loss of gas from the connected carbon dioxide pressure bottle, wherein a first embodiment of a riser is shown, which is designed as a capacitive measuring probe;

Figure 3:

an enlargement of the framed detail I of Fig. 2; and

Figure 4:

an enlargement of the framed detail II of FIG. 2.

Figure 5:

a longitudinal section through a further embodiment of a riser which is designed as a capacitive measuring probe; and

Figure 6:

a longitudinal section along section line 6-6 through the riser pipe of FIG .. 5

In Fig. 1, reference numeral 10 denotes a carbon dioxide pressure bottle a carbon dioxide fire extinguisher. This carbon dioxide pressure bottle is e.g. with a filling ratio of 1: 1.50 with carbon dioxide filled, giving a filling weight of 0.666 kg of carbon dioxide per liter of bottle volume equivalent. At a temperature of -20 ° C, the pressure bottle 10 is closed 62.8% filled with liquid carbon dioxide. At a temperature of + 20 ° C the volume fraction of the liquid phase is 82%. At a temperature of 27.2 C is the pressure bottle finally 100% with liquid carbon dioxide filled. From a temperature of 31 ° C (= critical temperature of carbon dioxide) there is no physical difference between liquid and liquid gaseous carbon dioxide, i. there is also no transition between a gaseous and liquid phase of carbon dioxide. It remains to be noted that the pressure in the pressure bottle of 19 bar at -20 ° C to 170 bar at + 60 ° C increases.

In Fig. 1, the carbon dioxide pressure bottle 10 with an inventive Device for detecting a loss of gas from the pressure bottle 10 equipped globally with the reference numeral 11. These Device 11 comprises a capacitive measuring probe 12, which consists of two Composed of electrodes. The latter extend over the entire height the pressure bottle 10 and are separated by an intermediate gap, in which the carbon dioxide forms a dielectric. Note that: (1) at Temperatures below 27.2 ° C the dielectric in the upper part of the intermediate gap is formed by gaseous carbon dioxide (at 20 ° C is the Measuring probe 10 e.g. 82% immersed in liquid carbon dioxide, while the remaining 18% are surrounded by gaseous carbon dioxide); (2) at temperatures between 27.2 ° C and 31 ° C the dielectric in the entire intermediate gap is formed by liquid carbon dioxide; and (3) at temperatures Above 31 ° C, the dielectric in the entire intermediate gap by supercritical Carbon dioxide is formed.

a) der Druckbehälter 10 zu 100 % mit flüssigem Kohlendioxid gefüllt ist, und somit ein Gasverlust von einigen Prozent nicht mehr zwangsläufig einer Änderung des Flüssigkeitsstands in der Druckflasche bewirkt; und

b) die kritische Temperatur des Kohlendioxids (31°C) überschritten ist, und das Kohlendioxid somit ein superkritisches Fluid bildet indem es keinen Unterschied mehr zwischen einer gasförmigen und einer flüssigen Phase gibt.

The operating principle of the device 11 is based on the surprising finding that a capacitive measuring device can measure changes in the liquid level in the pressure vessel 10 not only in a known manner, but that a gas loss of a few percent from the pressure vessel 10, a measurable change in capacitance of the probe 12 also then be clearly assigned if:

a) the pressure vessel 10 is filled to 100% with liquid carbon dioxide, and thus a gas loss of a few percent does not necessarily cause a change in the liquid level in the pressure bottle; and

b) the critical temperature of the carbon dioxide (31 ° C) is exceeded, and the carbon dioxide thus forms a supercritical fluid in that there is no difference between a gaseous and a liquid phase.

This operating principle of the device 11 is preferably as follows implemented. The capacitive measuring probe 12 is connected to a measuring module 14, which measures the capacitance of the capacitive probe 12 and its measured values to a microprocessor 16 passes. In a memory module 20, on that the microprocessor 16 has access are calibration values for a temperature range below and above the critical temperature of the carbon dioxide saved. By means of a temperature probe 18, the ambient temperature detected. The microprocessor 16 calculates, based on the measured temperature and the calibration value for this temperature, the carbon dioxide content of the pressure bottle 10 and compares this calculated carbon dioxide content with the target content the pressure bottle. If a Gasvertust is determined the one given Exceeds value, the microprocessor 16 generates an alarm message, e.g. is displayed by means of an optical and / or acoustic alarm module 22. In this way, a simple device for detecting a Gas loss created from a carbon dioxide pressure vessel, which is also at high ambient temperatures can be used.

Fig. 2 shows an exhaust valve 30 of a stationary carbon dioxide fire extinguishing device in which a capacitive probe 12 is integrated. Of the Top 31 of the outlet valve 30, which includes a triggering device is in Fig. 2 only indicated, since it for the understanding of the present invention is not important.

The outlet valve 30 comprises a valve body 31 with a valve base 32 with an external thread 34, with which it is in the bottleneck of a carbon dioxide pressure bottle is screwed in. It should be noted that the Carbon dioxide pressure cylinders used in stationary fire extinguishing devices are used in their bottleneck only a W 28.8 x 1/14 "thread according to DIN 477 for screwing in the valve base 32, i. that in the Valve base 32 relatively narrow space prevail.

Within the valve base 32, an inlet bore 36 is disposed, in a riser 38 opens axially this riser 38 extends into the proximity of the bottom of the bottle. Note that in a stationary carbon dioxide fire extinguisher the inlet bore 36 in the valve base 32 and the Riser 38 must have at least an inner diameter of 12 mm, to ensure that after triggering the fire extinguishing device, the Quenching gas with sufficiently low pressure loss via the riser 38 in the Outlet valve 30 can flow.

The capacitive measuring probe 12 is in the outlet valve 30 of FIG. 2 formed by the riser 38 and by an outer electrode tube 40, which surrounds the riser 38 with an intermediate gap 42. With others Words, the capacitive probe 12 comprises two coaxial tubular Electrodes, wherein the riser 38, the inner electrode, the electrode tube 40th the outer electrode is formed. The annular intermediate gap 42 between the both electrodes 38 and 40 is liquid, gaseous or supercritical Carbon dioxide, which is a dielectric between the two Forms electrodes 38 and 40.

Annular spacers 44, 44 'of an insulating material, the Wall thickness corresponding to the width of the gap 42, respectively by means of a pair of retaining rings 46, 46 'attached to the riser 38 and ensure that the annular intermediate gap 42 between the two Electrodes remain constant over the entire length of the probe 12. you note that the spacers 44, 44 'have local flats 45, 45', so that the carbon dioxide at the Abstandshaltem 44, 44 'along in the Intermediate gap 42 can flow. The reference numeral 48 is a ventilation opening at the upper end of the outer electrode tube 40, the ensures that the liquid level and the pressure in the intermediate gap 42 and the pressure bottle always agree.

The installation of the probe 12 in the valve base 32 is now based on of Fig. 3 described in more detail. An insulating sleeve 50 is on the upper end of the Riser 38 screwed. This insulating sleeve 50 comprises at its upper End a first external thread 52 with which they into an internal thread 52 'in one Bore of the valve base 32 is screwed in The lower end of the insulating sleeve 50 protrudes from the bore of the valve base 32 and is with a second external thread 54 provided. On this second external thread 54 is screwed the upper end of the outer electrode tube 40 so that it with its end face 56 fixed to a face 58 of the electrically conductive Valve socket 32 is pressed and thus in electrical contact with this stands. It should be emphasized that the insulating sleeve 50 thus the function an electrical insulator between riser 38 and valve base 32, a insulating spacer between riser 38 and outer electrode tube 40 and a fastening and pressing device for the outer Electrode tube 40 is satisfied. This multifunctional sleeve is a minimum Individual parts for the installation of the two measuring electrodes 38, 40 needed. you Note also that the insulating sleeve 50 is also an electrically conductive Outside wall may have, over which the valve base 32 and the outer Electrode tube 40 are electrically connected together. This will be the electrical contact between valve base 32 and outer electrode tube 40 even further improved.

The reference numeral 60 denotes a contact ring which is approximately the same inner and outer diameter as the end face 62 of the riser 38 has. This contact ring 60 is in a recess in a first End face of an insulating ring 64 fitted. The latter has the same inner diameter, however, a larger outer diameter than the contact ring 60th on and lies with its second end face on a shoulder surface 66 in the Inlet bore 36 on. By screwing the riser 38 by means of Isoliermuffe 50 in the valve base 32, the end face of the riser 38 firmly pressed against the contact ring 60, so that a reliable electrical Connection between riser 38 and contact ring 60 is made. In summary So it remains to be noted that the riser 38 in the inlet bore 36 of the valve base 32 with the contact ring 60 over a large area in contact stands, wherein the contact ring 60 through the insulating ring 64 from the conductive valve base 32 is reliably isolated.

The reference numeral 70 denotes a connection channel in the valve base 32, in the shoulder surface 66 forms an opening at which the Insulating ring 64 rests in the inlet bore 36. The insulating ring 64 has a Ring groove 72 in the end face which rests against the shoulder surface 66, wherein the Opening of the connection channel 70 opens into this annular groove 72. A puncture 74 of the insulating ring 64 extends from the annular groove 72 to the contact ring 60. An insulated terminal wire 76 is connected to the contact ring at a first end 60 firmly connected and through the through hole 74 and the annular groove 72nd of the insulating ring 64 inserted into the connection channel 70. The annular groove 72 prevents in this case that the connecting wire 76 is sheared off, if the Contact ring 60 is rotated in the inlet bore 36.

The description will now be continued with reference to FIG. 4. The connecting wire 76 is firmly connected to a rod-shaped connection element 78. The latter is sealed inserted into a cone-shaped insulating sleeve 80, the in turn by means of a clamping screw 82 in a conical bore 84 in Valve body is pressed sealed.

The reference numeral 90 in Fig. 4 is a board with an electronic Shadow shown fitted in a chamber 92 of the valve body is. A screw plug 94 closes the chamber 92 and at the same time fixes the Board 90 in the chamber 92. Above the connection element 78 is the board 90th connected to the riser 38, which is known to be the first electrode of the capacitive probe 12 is formed. Above the electrically conductive valve housing the board 90 is connected to the outer electrode tube 40, the As is known, the second electrode of the capacitive measuring probe 12 is formed. One Plug 96 sealed in a socket in screw plug 94th is inserted, it allows the board 90 via a connecting line 98 at external circuits or to connect external power sources.

On the board 90 are the measuring module 14, the microprocessor 16, the Temperature probe 18 and the memory module 20 housed. Above the Connecting line 98 is an alarm message either to an external alarm module or a central monitoring network forwarded.

In the embodiment of FIGS. 5 and 6, the riser 38 'with one end screwed into the inlet bore 36 of the valve base 32, whereby the electrical contact between valve base 32 and riser 38 'directly will be produced. Reference numeral 110 denotes an upper insulating sleeve which is pushed onto the riser 38 'and an end face 112 on the End face 58 of the valve base 32 abuts. The outer electrode tube 40 'is pushed with one end to the lower end of the upper insulating sleeve 110 and lies with its upper end face on a shoulder surface 114 of upper insulating sleeve 110 at. On the lower end of the riser 38 'is a Attachment sleeve 116 screwed. The latter has a cylindrical end 118, which is inserted into the lower end of the outer electrode tube 40 '. When tightening the mounting sleeve 116 is supported an annular Contact surface 120 on the lower end face of the electrode tube 40 'from, to the latter axially with its upper end face to the shoulder surface 114 of the to press upper insulating sleeve 110, which in turn with its end face 112 is pressed against the end face 58 of the valve base 32.

The lower attachment sleeve 116 advantageously comprises a metallic Kemkörper 122, in which the internal thread for screwing onto the riser 38 'is formed, and an insulating sleeve 124, which on the metallic Kemkörper 122 is placed and an electrical contact between the outer electrode tube 40 and the metallic core body 122 avoids. As an alternative to the insulating sleeve 124, the metallic core body 122 also be coated with an insulating material. As another alternative to the insulating sleeve 124, a mounting sleeve can be used which is made entirely of an insulating material. The solution with a metallic core body 122, however, is characterized by a larger mechanical strength in the event of severe temperature fluctuations therefore preferred. As in the embodiment of FIG. 2, at least guaranteed an annular spacer 44 made of an insulating material, that of annular intermediate gap 42 between the two tubes over the whole Length remains constant.

The reference numeral 130 in Fig. 5 denotes a locking pin in a Bore in the end face 58 of the valve base 32 is screwed and in a Recess of the upper insulating sleeve 110 engages such that it the latter blocked against twisting. A pierced locking pin 132 is advantageous as Used cable entry. Here is an insulated connection cable 134th through a cable channel 136 in the valve base 32 through the pierced Locking pin 132 in an outer recess 138 of the Isotationsmuffe 110th where it is electrically connected to the outer electrode tube 40 ' is.

The reference numerals 140, 142 in Fig. 5 denote lateral openings in lower and upper end of the outer electrode tube 40 '. These openings 140, 142 ensure that the intermediate gap 42 in immediate connection standing with the bottle interior.

It should be noted that while the present invention is only in context with the detection of a gas loss from a carbon dioxide pressure vessel was described, of course, but also on Other gases applicable are the similar properties as carbon dioxide exhibit.

Claims (17)

1. Carbon dioxide fire-extinguishing device comprising:

   a carbon dioxide pressure bottle (10) for storing extinguishing medium;

   a device for detecting gas loss from a carbon dioxide pressure bottle (10)

   characterized in that
   the device for detecting gas loss from the carbon dioxide pressure bottle (10) includes a capacitative measurement device (11) which is calibrated for a temperature range above and below the critical temperature of carbon dioxide.
2. Device according to Claim 1, comprising:

   a capacitative measurement probe (12) which extends over the whole hight of the pressure bottle (10);

   a measurement module (14) to measure the capacity of the capacitative measurement probe (12);

   a microprocessor (16) that associates a measured alteration in capacity with a corresponding loss of gas; and

   means for triggering an alert signal if the gas loss measured by the microprocessor exceeds a pre-set threshold.
3. Device according to Claim 2, comprising:

   a temperature probe (18); and

   a storage module (20) with calibration values for a temperature range below and above the critical temperature of carbon dioxide, the microprocessor (16), as a function of temperature, referring to these calibration values in order to attribute a corresponding loss of gas to a measured alteration in capacity
4. Device according to Claims 1, 2 or 3, comprising:

   an outlet valve (30) with a valve base (32) to be screwed on to a carbon dioxide pressure bottle (10), this valve base (32) being provided with an inlet hole (36):

   an ascending tube (38) opening into the inlet hole (36) of the valve base (32) so that when the fire extinguisher device is actuated, the carbon dioxide gas flows through the ascending tube (38) into the outlet valve (30); and

   a capacitative measurement probe (12) comprising two coaxial electrodes, the first electrode being formed by the ascending tube (38), and the second electrode being formed by an outer electrode tube (40) which surrounds the ascending tube (38) with a clearance space (42).
5. Device according to Claim 4, characterized in that:

   an insulating sleeve (50) surrounds the end of the ascending tube (38) in the inlet hole (36) and insulates it electrically from the conductive valve base (32);

   a contact element (60, 64) in the inlet hole (36) of the valve base (32), which is electrically insulated from the conductive valve base (32) and is in electrical contact with the first end of the ascending tube (38);

   the outer electrode tube (40) being in contact with the electrically conductive valve base (32).
6. Device according to Claim 5, characterized in that the ascending tube (38) is provided with an annular front face (62) as a contact face for the insulated element (60, 64).
7. Device according to Claim 6, characterized in that the insulated contact element (60, 64) comprises the following parts:

   a contact ring (60) with approximately the same internal and external diameter as the annular contact face (62) of the ascending tube (38); and an insulating ring (64) greater in external diameter than the contact ring (60), having one front face in contact with a shoulder surface (66) of the inlet hole (36) and in its other front face a recess into which the contact ring (60) fits.
8. Device according to Claim 7, characterized by:

   a connection channel (70) in the valve base (32), forming an opening in the shoulder surface (66) in contact with the insulating ring (64);

   an annular groove (72) in the front face of the insulating ring (64) that is in contact with this shoulder surface (66), the mouth of the connection channel (70) in the shoulder surface (66) communicating with this annular groove (72);

   a hole (74) bored through the insulating ring (64) from the annular groove (72) to the contact ring (60); and

   an insulated connecting wire (76) which has a first end solidly fixed to the contact ring (60) and is led through the hole (74) and the annular groove (72) in the insulating ring (64) into the connection channel (70).
9. Device according to Claim 8, characterized by a first connection piece (78), accessible from the exterior, sealed and electrically insulated in a hole bored in the valve base (32) and to which the second end of the connecting wire (76) is solidly connected.
10. Device according to one of Claims 5 to 9, characterized in that the outer electrode tube (40) is provided with an annular front face (56) which is pressed against an annular front face (58) of the valve base (32).
11. Device according to Claim 10, characterized in that one end of the insulating sleeve (50) protrudes out of the hole in the valve base (32) and that the electrode tube (40) is screwed on to this end of the insulating sleeve (50) in such a way that its annular front face is pressed firmly against the annular front face of the valve base (32).
12. Device according to one of Claims 5 to 11, characterized in that the insulating sleeve (50) is screwed into the inlet hole (36).
13. Device according to Claim 10, characterized in that:

    a first end of the insulating sleeve (50) is screwed into the inlet hole (36) and the second end of the insulating sleeve (50) protrudes from the inlet hole (36);

    the outer electrode tube (40) is screwed on to the second end of the insulating sleeve (50); and

    the insulating sleeve (50) is provided with an electrically conductive outer wall, by means of which the valve base (32) and the outer electrode tube (40) are electrically connected together.
14. Device according to one of Claims 5 to 13, characterized in that the ascending tube (38) is screwed into the insulating sleeve (50).
15. Device according to Claim 4, characterized in that:

    the ascending tube (38) has its upper end screwed into the inlet hole (36) in the valve base (32);

    an upper insulating sleeve (110) is pushed on to the upper end of the ascending tube (38');

    a lower fixing sleeve (116) is screwed on to the lower end of the ascending tube (38') wherein the fixing sleeve (116) when screwed on presses the outer electrode tube (40') axially against the upper insulating sleeve (110).
16. Device according to Claim 15, characterized in that:

    the upper insulating sleeve (110) is pressed against a front face (58) of the valve base (32).
17. Device according to Claim 15 or 16, characterized in that the lower fixing sleeve (116) comprises:

    a metal core element (122) screwed on to the lower end of the ascending tube (38'); and

    an insulator located between the metal core element (122) and the outer electrode tube (40').

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