DE102005049744B3 - Laboratory gas burner has gas leakage nozzle and adjusting mechanism wherein disrupting body which is displaceable in current of gaseous fuel withdrawing from gas leakage nozzle - Google Patents

Abstract

Laboratory gas burner has gas leakage nozzle (16) whereby a gas pipe is arranged before the gas leakage nozzle wherein a current of a gaseous fuel air withdrawing from the gas leakage nozzle drags along, in order to train a burnable gas mixture in burner pipe. An adjusting mechanism has a disrupting body (38) displaceable in current of gaseous fuel withdrawing from the gas leakage nozzle.

Description

The The invention relates to a laboratory gas burner with the features of the preamble of claim 1. In addition, the Invention also on laboratory gas burner with the features of one of the generic terms of the claims 4, 7, 10, 13, 16 and 19.

A laboratory gas burner with the features of the preamble of claim 1 is known from DE 197 10 670 A1 known. Here, a gas discharge nozzle is adjacent to an air supply opening, wherein the amount of air sucked from a fuel gas emerging from the gas discharge nozzle into the burner pipe located in front of it is determined by an adjustment valve with which the air supply opening can be partially or completely closed.

One Another laboratory gas burner with the characteristics of the generic term of the Claim 1 is a so-called Teklu burner in which the lower opening the burner tube by a rotatable on a thread and thereby height-adjustable disc completely or partially closed is. At a Teklu burner opens the gas outlet nozzle from below into an enlarged lower section of the cross section vertically aligned burner tube, leaving a Teklu burner also the features of the preambles of claims 4 and 7 fulfilled.

A laboratory gas burner having the features of the preambles of claims 10, 13 and 16 is known from DE 200 11 457 U1 known. In this document, a device for monitoring a burner head of a laboratory gas burner is described, which checks a conductivity between a monitoring electrode and a counter electrode, for example, consisting of the burner tube prior to the application of an ignition voltage for igniting a gas flame. For this purpose, the potential of the monitoring electrode with respect to the located at ground or ground potential burner tube is monitored in a concrete, located on the market embodiment of this known laboratory gas burner.

From the DE 20 2005 003 642 U1 It is known to monitor the function of a laboratory gas burner by not only applying an ignition voltage to an ignition electrode when igniting the gas flame of the laboratory gas burner, but also by applying a measuring voltage to the ignition electrode after ignition. This measuring voltage is an electrical alternating voltage having a first and a second half-wave profile, wherein a current flow generated between the electrode and the counter-electrode during the first half-wave curve as an indication of flame formation at the burner head and a generated during the second half-wave waveform current flow between the electrode and the burner tube as an indication of a fault is considered.

The from the DE 20 2005 003 642 U1 known laboratory gas burner also fulfills the features of the preamble of claim 19, by having its housing at the top behind the burner head has three transverse grooves for storing Impfösen. A typical use of a laboratory gas burner is in the sterilization of inoculation loops.

Of the Invention is based on the object, the known laboratory Gas burner continue to develop their performance and reliability to increase. In particular, it should be possible, a very hard Gas flame to create, without losing the possibility that measurement ratio to adjust from fuel gas to air, to less if necessary be able to train hard gas flame.

SOLUTION

The The object of the invention is achieved by a laboratory gas burner solved with the features of claim 1. Preferred embodiments of the new laboratory gas burner are in the claims 2 to 21, wherein the feature combinations of claims 4, 7, 10, 13, 16 and 19 are also considered as separate inventions become.

DESCRIPTION THE INVENTION

In a new laboratory gas burner having the features of claim 1, adjusting means for adjusting a mixing ratio of fuel gas to air in a gas mixture formed by entraining air discharged from a gas exhaust nozzle into a burner tube disposed in front of the gas exhaust nozzle, includes an in-cylinder gas burner the flow of the emerging from the gas outlet nozzle fuel gas traveling on bluff body. This interfering body influences the flow of the fuel gas leaving the gas outlet nozzle in such a way that, depending on its current displacement position, it more or less prevents it from entraining air into the burner tube. In the new laboratory gas burner is therefore omitted to narrow the air duct opening in its free cross-section, in order to reduce the proportion of air in the formed gas mixture in this way adorn. Instead of the supply of air is acted upon in the new laboratory gas burner on the flow of the gas leaving the gas outlet nozzle fuel gas and its ability to entrain air. This has the advantage that the air supply opening of the new laboratory gas burner can be very large, without means must be provided to close them, which would be associated with considerable design problems in a very large air supply opening with a compact design of the laboratory gas burner. The new laboratory gas burner is therefore suitable for the formation of a very hard gas flame. Nevertheless, it is possible to selectively reduce the proportion of air in the combustible gas mixture with the aid of the bluff body in order to form a less hard gas flame if necessary.

Concrete can the bluff body the Flow of Fuel gas depending on its current displacement more or less strongly deflected laterally, whereby the entrainment effect of the fuel gas in relation changed to the air becomes.

at The new laboratory gas burner can rely on means for modifying the clear cross-section of the air supply opening throughout be waived. That is, the adjusting means for adjusting of the mixing ratio from fuel gas to air can only include the movable interfering body.

Also when in the new laboratory gas burner in the flow of the emerging from the gas outlet nozzle Fuel gas movable sturgeon provided is, the adjusting means for adjusting the mixing ratio from fuel gas to air in the gas mixture one or more air supply opening (s) have, whose free cross section with a closure element variable is.

If the gas outlet nozzle from below into a cross-sectionally extended lower area of the vertical aligned burner tube opens, can be the gas outlet nozzle adjacent air supply opening in an upper wall of the extended lower portion of the burner tube, laterally next to the free cross section of the unexpanded upper Be provided area of the burner tube. Unintentionally the burner tube descending substances, especially liquids, tend not to the air supply opening and in particular to contaminate a closure element associated therewith, whereby the function of the air supply opening and In particular, the function of the closure element to be hindered can. The substances move rather through the free cross section the unexpanded upper portion of the burner tube and at each Air supply opening in the upper wall of the extended lower portion of the burner tube past. At the bottom of the burner tube, they can be known per se Make way through a liquid drain opening exit the laboratory gas burner. In a preferred embodiment of the new laboratory gas burner are two air supply openings at two opposite ones Side of the burner tube in the upper wall of the extended lower Provided portion of the burner tube, these two air supply openings a roof-shaped Closure element of the adjustment device for adjusting the mixing ratio is assigned from fuel gas to air in the gas mixture. By the Location of this roof-shaped Closing element opposite the air supply openings is adjustable, with the adjustment of the effective free cross-section of the air supply openings be varied.

The roof-shaped Closure member may be about a horizontal axis from the air supply openings be swiveled upwards. Here, the pivoting movement over a around this horizontal axis rotatable control element of the laboratory gas burner be triggered by a user of the laboratory gas burner.

If in the new laboratory gas burner, the gas outlet nozzle is extended from below into a cross-sectionally enlarged one bottom portion of the vertically aligned burner tube opens and the extended lower portion of the burner tube down through a removable bottom plate is closed, this bottom plate can for strong ventilation, d. H. to provide a particularly large air supply opening in the neighborhood the gas outlet nozzle removable be. In the removable bottom plate can also be provided a liquid drain opening to be through this the escape of the burner tube run down liquids to allow out of the laboratory gas burner even if the bottom plate is the extended lower portions of the burner tube closes down. For this Case, the new laboratory gas burner can typically be another in Have their effective free cross-section variable air supply opening.

Around the strong ventilation ensure that the burner tube does not exist can be the extended lower section of the burner tube at the bottom a housing the laboratory gas burner end, this bottom by riot feet of the laboratory gas burner runs at a distance above a flat contact surface of the laboratory gas burner. So Is it possible, that air is laterally over the riot area under the bottom of the case and flows from there into the burner tube.

To safely store the gas outlet nozzles even at the bottom open burner tube, a can Gas ejection nozzle forming nozzle body be screwed from below into a running at the bottom of the extended lower portion of the burner tube transverse block, through which also the fuel gas flows to the gas outlet nozzle.

Of the new laboratory gas burners, as is common in the art, one upper part of the burner tube and a cylinder jacket-shaped Ausblasschutz have a comprehensive burner head made of metal. This one is in operation of the laboratory gas burner heated by the gas flame is not insignificant. Around this heat from the rest of the laboratory gas burner is at the new Laboratory gas burner preferably between the burner head and a also made of metal lower part of the burner tube as well a likewise made of metal housing of the laboratory gas burner Sealing and insulating body arranged.

Of the Sealing and insulating body may be formed of ceramic material. Cost effective and sufficient in view of the occurring thermal loads but is also the formation of the sealing and insulating body high temperature resistant plastic. A sealing and insulating body Kuststoff also has advantages in terms of its sealing function on, which prevents contamination between the burner head or the burner tube on the one hand and the housing on the other hand into the interior of the housing enter.

In Regarding its insulating function, the sealing and insulating body is included the new laboratory gas burner primarily for one provided thermal insulation of the burner head. He does, however also an electrical insulation of the burner head. In the face of a typically over the burner tube drains off ignition for the Ignite However, a gas flame, it is necessary that the burner head reliable at ground or earth potential. It is also before activation the ignition voltage makes sense, to check that the burner head, if it is removable for cleaning purposes, for example, indeed on the case is arranged. For this purpose, the removable burner head at the new Laboratory gas burner to be secured by a screw in the secured State of the burner head on the one hand the burner head and on the other hand a in the sealing and insulating body embedded monitoring electrode connects electrically to a contact at ground or ground potential. By checking if the monitoring electrode is at ground or ground potential, it can then be determined whether the screw with which the burner head is secured, so far screwed in, that also the burner head reliably on Ground or ground potential is located.

Around to check if the torch head is placed correctly and at ground or earth potential can also be another part of the burner head, such as a cylindrical lower portion of the upper part of the burner tube, be provided to a lying at ground or ground potential contact on the one hand and a monitoring electrode on the other to contact electrically.

to automatic ignition a gas flame, it is common in a laboratory gas burner, a gas bypass on the outer circumference the burner tube and a the upper end of the burner tube opposite ignition electrode provided. By applying an ignition voltage to the ignition electrode a spark jumps between the ignition electrode and the burner tube and ignites the combustible gas mixture flowing in the gas bypass at a lower flow rate. In the new laboratory gas burner, it is preferable if the combustion tube in addition to its upper end a radially outward flat collar has.

If this radially outward directed collar at least the free cross-section of the gas bypass Covering upwards, it prevents liquids flowing from the top Drain the laboratory gas burner, get into the gas bypass and this can pollute.

Also prevented the radially outward Covenant in case of strong air flow of the laboratory gas burner of above the blowing out of burning in the gas bypass part of the gas flame and thus at all the blowing out of the gas flame of the laboratory gas burner.

moreover can be the radially outward directed flat collar of the burner tube facilitate the ignition process by he has an outer edge with strong curvature and correspondingly high field strength concentration with applied ignition voltage formed.

Ultimately can due to the radially outward collar on the upper end of the burner tube to a hitherto usual bending of the ignition electrode be dispensed with towards the burner tube. Rather, the ignition electrode from the free end of a straight, vertical wire be formed, which is opposite to the radially outwardly directed collar. On a rotational position of the ignition electrode then no more attention must be paid to their vertical axis.

If for monitoring its function, the new laboratory gas burner preferably has an ignition and monitoring device which applies after the application of an ignition voltage a smaller than the ignition voltage monitoring voltage to the ignition electrode and checks whether the potential of a monitoring electrode against Above the burner tube or another located at ground or ground potential counter electrode of an initial value, which it assumes without flame and without ignition or monitoring voltage, to a reduced, but above the ground or earth potential value drops. Surprisingly, it is found that a potential difference between the monitoring electrode and its counter-electrode depends on the monitoring voltage applied to the ignition electrode via the flame. Specifically, when the gas flame is burning and the plasma present in the region of the gas flame is present, the monitoring voltage at the same time reduces the potential difference between the monitoring electrode and its counterelectrode. However, this reduction does not lead down to the ground or ground potential of the counter electrode.

moreover is the measure of Reduction of the potential difference between the monitoring electrode and its Counter electrode dependent the composition and temperature of the gas flame, d. H. the type of fuel gas and the composition of the gas mixture from air and fuel gas. When it is determined what value the Potential of the monitoring electrode on the concern of the monitoring voltage falls off when the gas flame is burning, This can be a conclusion on the type of fuel gas used or monitoring various operating parameters of the laboratory gas burner done.

Concrete can for monitoring the potential of the monitoring electrode the monitoring electrode be connected to an open input of an operational amplifier, wherein the output of the operational amplifier as a measure of the current Potential of the monitoring electrode used becomes.

Around a limited number of inoculation loops defined on the housing The new laboratory gas burner can store at the back of the housing from a perforated sheet metal section U-shaped curved Impfösenhalter be provided. In this vaccine eyelet holder can the inoculation loops be plugged in with their handles down. If the vaccine holder while a plurality of Impfösen at the free ends of their downward facing handles in backwards inclined fanned out Arrangement next to each other, point the potentially contaminated areas of the inoculation loops to theirs Free ends have a maximum distance between each other, and it is possible, specifically a single Impföse and the vaccine holder to remove without being in unwanted contact with the others inoculation loops to get.

Of the Inoculation can be screwed to the back of the case with the new laboratory gas burner and to that extent also be removable, if he does not need or the space occupied by him at the back of the case for other attachments to the housing needed becomes.

advantageous Further developments of the invention will become apparent from the claims, the Description and the drawings. The in the introduction to the description advantages of features and combinations of several Features are merely exemplary and may be alternative or cumulative come into effect, without the benefits of mandatory embodiments of the invention must be achieved. Other features are the drawings - in particular the illustrated Geometries and the relative dimensions of several components to each other as well as their relative arrangement and operative connection - can be seen. The combination of features of different embodiments the invention or features of different claims is also different from the ones chosen The antecedents of the claims possible and is hereby stimulated. This also applies to such features as in separate drawings are shown or in their description to be named. These features can be combined with features of different claims. As well can in the claims listed Features for more embodiments the invention omitted.

SUMMARY THE FIGURES

in the The invention is based on preferred embodiments with reference to the attached Drawings closer explained and described.

1 shows a view from the front of a standing on a footprint laboratory gas burner.

2 shows a section through an embodiment of the internal structure of the laboratory gas burner according to 1 wherein the cutting plane is vertical along the axis of its burner tube.

3 shows a section through an alternative embodiment of the internal structure of the laboratory gas burner according to 1 in which the cutting plane is opposite to the cutting plane of 2 rotated by 90 ° about the axis of the burner tube.

4 shows a vertical section through a further alternative embodiment of the internal structure of the laboratory gas burner according to 1 , wherein the sectional plane of those according to 2 equivalent.

5 shows a vertical section through the Embodiment of the internal structure of the laboratory gas burner according to 4 , where the sectional plane opposite 4 rotated by 90 ° about the axis of the burner tube, so that they correspond to the cutting plane 3 equivalent.

6 shows a side view of the burner tube forming and surrounding components of another embodiment of the laboratory gas burner according to 1 ,

7 FIG. 4 is a flowchart of a laboratory gas burner igniter and monitor according to FIG 1 ,

8th on the other hand, the course of an ignition and monitoring voltage on the one hand and a potential signal on the other hand, that of the ignition and monitoring device according to 7 is evaluated.

9 is a side view of an embodiment of the laboratory gas burner according to 1 in which an inoculation loop holder can be seen on the back of the laboratory gas burner with a loop inserted therein.

10 shows the basic shape of a sheet from which the Impfösenhalter according to 9 is bent; and

11 shows a separate rear view of the Impfösenhalters according to 9 with three inserted inoculation loops.

DESCRIPTION OF THE FIGURES

The in 1 shown laboratory gas burner 1 has a housing 2 up, about riot feet 3 on a riot space 4 for the laboratory gas burner 1 gets up. Through the riot feet 3 remains between the bottom 5 of the housing 2 and the riot space a free space 6 through the air in openings at the bottom 5 of the housing 2 can flow in. This will be discussed further below. On top of the case 2 is a burner head 7 arranged. At the front of the case 2 are controls 8th and 9 for the laboratory gas burner 1 and a display 10 about which the operator of the laboratory gas burner 1 and on which the operating state of the laboratory gas burner 1 can be displayed.

2 shows a vertical section through an embodiment of the internal structure of the laboratory gas burner 1 according to 1 along the vertically aligned axis 11 his burner tube 12 , The burner tube 12 is essentially constructed in two parts, with both a lower part 13 as well as an upper part 14 several different areas with different detail functions of the burner tube 12 formed. The lower part 13 of the burner tube 12 includes a lower area 15 in which the horizontal free cross-section of the burner tube 12 is funnel-shaped from top to bottom. In this lower area 15 of the burner tube 12 opens a gas outlet nozzle 16 one from a nozzle body 17 is trained. The nozzle body 17 is under interposition of a sealing ring 18 from below into a cross block 19 screwed, extending across the free cross-section of the burner tube 12 extends at the lower end, but does not close this free cross-section. In the cross block 19 is a gas supply channel 20 formed by the fuel gas via transverse bores 21 in the nozzle body 17 can enter to get out of the gas outlet nozzle 16 resign. Because the case 2 at its bottom 5 below the burner tube 12 a large air supply opening 22 can, that from the gas outlet nozzle 16 outgoing fuel gas air from the environment of the laboratory gas burner through the free space 6 in the burner tube 12 entrain to get into the burner tube 12 to form a combustible gas mixture. This gas mixture initially reaches a cylindrical area 23 of the lower part 13 of the burner tube 12 until it is in a cylindrical area 24 of the upper part 14 of the burner tube 12 transgresses. In the upper part 14 of the burner tube 12 is from above an insert body 25 with cross holes 26 used a gas bypass 27 for the combustible gas mixture in the burner tube 12 formed. The ignition of a gas flame at the top 28 of the burner tube 12 takes place in the area of this gas bypass 27 with the help of an ignition voltage, which is connected to an ignition electrode 29 opposite the burner tube 12 is created. Through one between the ignition electrode 29 and the burner tube 12 Skipping sparks that is through the gas bypass 27 ignited flowing gas mixture. To facilitate the formation of the spark, has the insert body 25 at the top 28 of the burner tube 12 a radially outwardly directed flat collar 76 on. The spark jumps between the strongly curved outer edge of this radial collar 76 and the ignition electrode 29 above. In addition, the federal government covers up 76 the gas bypass 27 between the insert body 25 and the upper part 14 of the burner tube 12 , Thus, a blowing out of the burning gas mixture here by a flow of the laboratory gas burner 1 prevented from above as well as a fouling of the gas bypass 27 for example, by liquids from the top of the burner tube 12 drip or flow. About the axis 11 of the burner tube 12 away lies the ignition electrode 29 a monitoring electrode 30 across from. Their function will be later related to the 7 and 8th be explained in more detail. Both electrodes 29 and 30 are through insulation coats 31 except for their upper free ends opposite the upper part 14 of the burner tube 12 electrically isolated. They are over clamped retaining rings 32 between a radial collar 33 of the upper part 14 of the burner tube 12 and a counter-plate 34 at the burner head 7 secured. The outer circumference of the burner head 7 is made by a cylinder jacket-shaped blow-out protection 35 for the gas flame of the laboratory gas burner 1 according to 1 educated. Except for the insulating coats 31 the electrodes 29 and 30 is the entire burner head 7 made of metal, and it is altogether of the remainder of the laboratory gas burner 1 ie at the top of its housing 2 removable. In the process, the lower areas of the electrodes become 29 and 30 and their insulating coats 31 from a sealing and insulating body 36 pulled out. The sealing and insulating body 36 is between the burner head 7 made of metal and the metal housing 2 and also made of metal lower part 13 of the burner tube 12 especially provided as a seal against contamination and thermal insulation. The sealing and insulating body 36 is on the cylinder jacket-shaped area 23 of the lower part 13 of the burner tube 12 beware and a sealing ring 37 is between the upper part 14 of the burner tube 12 and the sealing and insulating body 36 intended. The mixing ratio of fuel gas to air in the in the burner tube 12 generated gas mixture is by moving a bluff body 38 more or less far in front of the gas outlet nozzle 16 variable. This procedure is done perpendicular to the drawing plane according to 2 or also, as here by an arrow 39 is indicated in the drawing plane according to 2 , When the bluff body 38 in front of the gas outlet nozzle 16 it reduces the ability of the gas outlet nozzle 16 outflowing fuel gas, air through the air supply opening 22 to suck. Accordingly, the gas mixture consists of larger proportions of fuel gas, as if the bluff body 38 from the axis 11 of the combustion tube, on which the gas outlet nozzle 16 is aligned, further away. Ultimately, in 2 a circuit board 40 indicated on the electronic components to form a control of the laboratory gas burner 1 according to 1 can be arranged.

Both the following description of 3 as well as the in 3 Plotted reference numerals focus on the differences of the embodiment of the basis 3 sketched laboratory gas burner to that according to 2 and to details which are the same in both embodiments and in 3 but not in 2 you can see. The differences between the embodiments of the laboratory gas burner according to the 2 and 3 Concentrate on the upper end 28 of the burner tube 12 , According to the embodiment of 3 here is no covenant 76 according to 2 intended. In addition, the Störkörper 38 here in the other horizontal direction movable, as by an arrow 41 is indicated. Better than in 2 is in 3 to see that too in 2 existing air supply opening 22 not through the cross body 19 is blocked, in which the nozzle body 17 is screwed. Next shows 3 from 2 not resulting electrical contact of the burner head 7 and the housing 2 about screws 42 and 43 passing through the sealing and insulating body 36 up to electrical contacts 44 and 45 passing through that at the bottom of the sealing and insulating body 36 are provided and to the board 40 as well as the lower part 13 of the burner tube 12 to lead. With the screw 43 becomes the case 2 through the sealing and insulating body 36 through and over the contact 45 as well as the lower part 13 of the burner tube 12 placed at ground or earth potential. The same applies to the burner head 7 in terms of the screw 42 and the contact 44 , But here is also a monitoring electrode 46 provided in the sealing and insulating body 36 is embedded, and that of the screw 42 when contacted with the screw 42 the burner head 7 at the rest of the laboratory gas burner 1 is secured. By monitoring whether the monitoring electrode 46 is at ground or ground potential, it can be checked if the screw 42 so far screwed in that they are the monitoring electrode 46 with the electrical contact 44 connects, which is synonymous with that of the burner head 7 its proper position on the case 2 occupies. Contrary to the illustration in 3 can a head 47 the screw 42 between the Radialbund 33 and the counter-plate 34 being caught, being in the radial covenant 33 over the head 47 only one penetration hole for a tool exists to the screw 42 captive on the burner head 7 to secure.

The in the 4 and 5 sketched another embodiment of the laboratory gas burner 1 is again explained in more detail only with reference to the differences from the embodiments described so far and is accordingly also provided only with reference to these differences with reference numerals. The design of the burner tube 12 at its upper end 28 or the insert body present here 25 corresponds to 3 ie it is not a radial collar 76 according to 2 available. That's what the electrodes are for 29 and 30 at their insulation-free ends to the axis 11 of the burner tube 12 bent over. It therefore depends on the rotational position of the electrodes 29 and 30 inside their insulation coats 31 opposite the axis 11 at. Furthermore, according to the 4 and 5 a removable bottom plate 48 provided to the air supply opening 22 on the bottom 5 of the housing 2 optionally to close. If the bottom plate 48 is removed through the air supply opening 22 a strong ventilation of the burner tube 12 from underneath. This can be used to form a particularly hard gas flame with the laboratory gas burner 1 be used. In the case the formation of such a hard gas flame is in the embodiment of the laboratory gas burner 1 according to the 4 and 5 no influence on the composition of the burner tube 12 trained gas mixture provided. That is, the disruptive body 38 according to the 2 and 3 is not present. However, in the lower area 15 of the burner tube 12 another air supply opening 49 provided, which is an adjustable closure element 50 assigned. By, for example, the in 5 recognizable distance of the closure element 50 to the air supply opening 49 can be enlarged, even with the bottom plate attached 48 increasingly more air from that from the gas outlet nozzle 16 escaping fuel gas into the burner tube 12 be entrained. Conversely, the proportion of air in the gas mixture in the burner tube 12 smaller if the closure element 50 closer to the air supply opening 49 is introduced and thus closes it more.

6 , which is not just a side view, but also in relation to the previous one 2 to 5 the blow-out protection 35 of the burner head 7 is omitted, outlines another way to form air supply openings 51 in the lower part 13 of the burner tube 12 , Specifically, the air supply openings 51 here in the upper wall of the lower section extended in cross-section 15 provided, so when looking along the axis 11 next to the free cross-section of the cylinder jacket-shaped area 23 , This will prevent liquids from entering the burner tube 12 run down, the air supply openings 51 and the roof-shaped closure element associated therewith 52 can pollute. However, the liquids can pass through a drain opening 53 in the bottom plate 48 expire. With arrows 54 is in 6 indicated that the roof-shaped closure element 52 upwards from the air supply openings 51 can be moved away to release this. This can be done by pivoting the roof-shaped closure element 52 about a horizontal axis above one of the controls 8th and 9 according to 1 respectively.

7 outlined an ignition and monitoring device 55 for the laboratory gas burner 1 , The ignition and monitoring device 55 acts on the ignition electrode reproduced on the right 29 via a voltage generator 56 first with an ignition signal 57 ,

This ignition signal consists of an ignition voltage between the ignition electrode 29 and the upper end 28 that with the electrical earth 58 connected burner tube 12 , Due to the voltage difference sparks jump between the ignition electrode 29 and the burner tube 12 over that in the burner tube 12 created gas mixture first in the gas bypass 27 Ignite, then starting from the desired, the entire gas mixture detected gas flame 59 formed. After igniting the gas flame 59 sets the ignition and monitoring device a monitoring signal 60 to the ignition electrode 29 which can have the same basic shape as the ignition voltage, but is much smaller than this. The ignition and monitoring device 55 can the monitoring signal 60 even before the ignition signal is applied 57 to the ignition electrode 29 create the initial state of the laboratory gas burner 1 before igniting the gas flame 59 to check. This input check is also without the monitoring signal 60 possible, wherein the ignition and monitoring electrode in each case, a potential signal 61 it monitors from the monitoring electrode 30 via an operational amplifier 62 receives, at its open entrance, the monitoring electrode 30 connected.

The signals coming from the ignition and monitoring device 55 are sent out or potentially received are in 8th shown. Top in 8th is for different operating states A to F at the ignition electrode 29 voltage applied while in the lower part of 8th the potential signal 61 is shown at the same time via the operational amplifier 62 from the monitoring electrode 30 Will be received. In operating state A is from the ignition and monitoring device 55 Checks if the laboratory gas burner is in a proper condition. There is no voltage at the ignition electrode, although here the monitoring voltage could be present. In any case, a constant potential signal of here 5 V is received by the monitoring electrode. In operating state B, an ignition pulse of a few kilovolts is applied to the ignition electrode. During the operating state B is by the ignition and monitoring device 55 no potential signal detected by the monitoring electrode. In the operating state C, a monitoring signal, which here consists of decaying alternating voltage pulses, but could also be a DC voltage, is applied to the ignition electrode. With burning gas flame 59 As a result, a potential signal that has dropped from 5 V but not reduced to 0 V is received by the monitoring electrode. The drop in the potential signal is characteristic of the operating conditions under which the laboratory gas burner is currently operated, and of the fuel gas burned thereby. In the operating state D, it is assumed here that the gas flame 59 is extinguished, for example by blowing. As a result, the potential signal from the monitor electrode rapidly increases again to 5V. This allows the ignition and monitoring device to an immediate new Zün the gas flame 59 be initiated with a pulse-shaped ignition voltage, as indicated in the operating state E. The operating state F shows the case of contamination of the burner head of the laboratory gas burner, which results in electrical contacting of the ignition / or monitoring electrode with the ground potential burner tube. As a result, the potential signal from the monitoring electrode drops very quickly to zero. In this case, the ignition and monitoring device should try no reignition of the gas flame, but for example, issue a warning signal.

9 shows the laboratory gas burner 1 in a side view, out of which a Impfösenhalter 63 visible to the back 64 of the housing 2 screwed on. The vaccine holder 63 serves to hold Impfösen 65 with their handles 66 to the bottom in the Impfösenhalter 63 can be inserted. However, the vaccine holder is 63 only for a small number of inoculation loops 65 intended. Behind the vaccine holder 63 is at the back 64 of the housing 2 still gas connection 67 to supply the laboratory gas burner 1 indicated with fuel gas.

10 gives the outline of a sheet 68 again, from which the Impfösenhalter 63 according to 9 Is bent in a U-shape. A middle part 69 of the sheet 68 has two screw holes 70 for screwing the Impfösenhalters 63 to the housing 2 of the laboratory gas burner 1 on. In a lower part 71 of the sheet 68 are three holes 72 provided for receiving the tapered lowermost end of each handle of a Impföse. In an upper part above 73 of the sheet 78 there is a recess 74 with three extensions 75 for receiving a handle of a Impföse each.

11 outlines a back view of the one out of the sheet metal 68 according to 10 curved inoculum holder 63 , here are three inoculation loops 65 with their handles 66 are plugged in. You can see the fanning out of the inoculation loops 65 through the vaccine holder 63 , You can not see that the inoculation loops 65 Moreover, they are inclined to the rear, but what is not 9 evident. The size relationships in the Impfösen 65 are in the 9 and 11 not necessarily true to life in relation to the inoculum holder. The inoculation loops 65 including their handles 66 are typically longer than shown here. For secure mounting but it is sufficient that they are with your the actual Impfösen 65 opposite ends of their handles 66 into the vaccine holder 63 be plugged in.

1

Laboratory gas burner

2

casing

3

Aufstandfuß

4

footprint

5

bottom

6

free space

7

burner head

8th

operating element

9

operating element

10

display display

21

cross hole

22

Lufzuführungsöffnung

23

cylindrical Area

24

cylindrical Area

25

insert body

26

cross hole

27

gas bypass

28

upper The End

29

ignition electrode

30

monitoring electrode

11

axis

12

burner tube

13

lower part

14

upper part

15

extended Area

16

gas discharge nozzle

17

nozzle body

18

seal

19

cross block

20

Gas supply channel

31

insulating

32

retaining ring

33

radial collar

34

counterplate

35

blowout

36

sealants and insulator

37

seal

38

disturbing body

39

arrow

40

circuit board

41

arrow

42

screw

43

screw

44

Contact

45

Contact

46

monitoring electrode

47

head

48

baseplate

49

Air supply port

50

closure element

61

potential signal

62

operational amplifiers

63

Inoculation

64

back

65

inoculating loop

66

brains

67

gas connection

68

sheet

69

midsection

70

screw hole

51

Air supply port

52

closure element

53

drain hole

54

arrow

55

Ignition and monitoring

direction

56

voltage generator

57

ignition signal

58

earth

59

gas flame

60

heartbeat

71

lower part

72

hole

73

upper part

74

perforation

75

extension

76

Federation

Claims (21)

A laboratory gas burner having a gas discharge nozzle with a burner tube disposed in front of the gas discharge nozzle, into which a flow of fuel gas leaving the gas discharge nozzle entrains air to form a combustible gas mixture in the burner tube, the air passing through an air supply opening adjacent the gas discharge nozzle, and an adjusting device for setting a mixing ratio of fuel gas to air in the gas mixture, characterized in that the adjusting device into the flow of the gas from the gas outlet nozzle ( 16 ) leaking fuel gas movable bluff body ( 38 ) having. Laboratory gas burner according to claim 1, characterized in that the disruptive body ( 38 ) deflects the flow of the fuel gas depending on its current displacement position more or less laterally. Laboratory gas burner according to claim 1 or 2, characterized in that the adjusting means for adjusting the mixing ratio of fuel gas to air in the gas mixture no means for changing the free cross section of the air supply port ( 22 ) having. Laboratory gas burner, in particular according to one of claims 1 and 2, with a gas outlet nozzle, with a burner tube arranged in front of the gas outlet nozzle, into which a flow of a gas emerging from the gas outlet nozzle entrains air in order to form a combustible gas mixture in the burner tube, the air passing through an air inlet opening adjacent to the gas outlet nozzle, and with an adjusting device for setting a mixing ratio of fuel gas to air in the gas mixture, wherein the gas outlet nozzle opens from below into a cross-sectional widened lower portion of the vertically oriented burner tube, characterized in that the air supply opening ( 51 ) in an upper wall of the extended lower area ( 15 ) of the burner tube ( 12 ), laterally next to the free cross-section of the unexpanded upper area ( 23 ) of the burner tube ( 12 ) is provided. Laboratory gas burner according to claim 4, characterized in that two air supply openings ( 51 ) on two opposite sides of the burner tube ( 12 ) and that a roof-shaped closure element of the adjusting device for setting a mixing ratio of fuel gas to air in the gas mixture in its position relative to the air supply openings ( 51 ) is adjustable. Laboratory gas burner according to claim 5, characterized in that the roof-shaped closure element ( 52 ) about a horizontal axis from the air supply openings ( 51 ) is pivotable upwards away. Laboratory gas burner, in particular according to one of claims 1 to 6, with a gas outlet nozzle, with a burner tube arranged in front of the gas outlet nozzle into which a flow of a fuel gas emerging from the gas outlet nozzle entrains air in order to form a combustible gas mixture in the burner tube, the air passing through a gas supply nozzle adjacent the air supply opening passes through, and with an adjusting device for adjusting a mixing ratio of fuel gas to air in the gas mixture, wherein the gas outlet nozzle opens from below into a cross-sectional enlarged lower portion of the vertically oriented burner tube, characterized in that the extended lower Area ( 15 ) of the burner tube ( 12 ) down through a removable bottom plate for strong ventilation ( 48 ) at least to one in the bottom plate ( 48 ) provided liquid drain opening ( 53 ) is closed. Laboratory gas burner according to claim 7, characterized in that the extended lower portion ( 15 ) of the burner tube ( 12 ) on the bottom ( 5 ) of a housing ( 2 ) of the laboratory gas burner ( 1 ) ends, the bottom ( 5 ) by riot feet ( 3 ) of the laboratory gas burner ( 1 ) at a distance above a flat contact surface ( 4 ) of the laboratory gas burner ( 1 ) runs. Laboratory gas burner according to claim 7 or 8, characterized in that a gas outlet nozzle ( 16 ) forming nozzle body ( 17 ) from below into one at the bottom of the extended lower area ( 15 ) of the burner tube ( 12 ) extending transverse block ( 19 ) is screwed, through which the fuel gas to the gas outlet nozzle ( 16 ) flows. Laboratory gas burner, in particular according to one of claims 1 to 9, with a gas outlet nozzle, with a burner tube arranged in front of the gas outlet nozzle, into which a flow of a gas emerging from the gas outlet nozzle entrains air in order to form a combustible gas mixture in the burner tube, the air passing through one of the gas outlet nozzle adjacent air supply opening passes through, and comprising a burner comprising a top of the burner tube and a cylinder jacket-shaped Ausblasschutz comprehensive metal burner head, characterized in that between the burner head ( 7 ) and a likewise made of metal lower part ( 13 ) of the burner tube ( 12 ) as well as a likewise metal housing ( 2 ) of the laboratory gas burner ( 1 ) a sealing and insulating body ( 36 ) is arranged. Laboratory gas burner according to claim 10, characterized in that the sealing and insulating body ( 36 ) is formed of high temperature resistant plastic. Laboratory gas burner according to claim 11, characterized in that the removable burner head ( 7 ) by a screw ( 42 ) secured in the secured state of the burner head ( 7 ) on the one hand the burner head ( 7 ) and on the other hand, a in the sealing and insulating body ( 36 ) embedded monitoring electrode ( 46 ) electrically with a contact ( 44 ) connects to ground or ground potential. Laboratory gas burner, in particular according to one of claims 1 to 12, with a gas outlet nozzle, with a burner tube arranged in front of the gas outlet nozzle into which a flow of a gas emerging from the gas outlet nozzle entrains air in order to form a combustible gas mixture in the burner tube, the air passing through an air inlet opening adjacent to the gas outlet nozzle, and having an ignition device comprising a gas bypass on the outer circumference of the burner tube and an ignition electrode located opposite the upper end of the burner tube, characterized in that the burner tube ( 12 ) at its upper end ( 28 ) a radially outwardly directed collar ( 76 ) having. Laboratory gas burner according to claim 13, characterized in that the radially outwardly directed collar ( 76 ) at least the free cross section of the gas bypass ( 27 ) covers upwards. Laboratory gas burner according to claim 13 or 14, characterized in that the ignition electrode ( 29 ) is formed from the free end of a straight, vertically extending wire, which is the radially outwardly directed collar ( 76 ) is opposite. Laboratory gas burner, in particular according to one of claims 1 to 15, with a gas outlet nozzle, with a burner tube arranged in front of the gas outlet nozzle into which a flow of a gas emerging from the gas outlet nozzle entrains air in order to form a combustible gas mixture in the burner tube, the air passing through a gas inlet nozzle adjacent the air supply opening passes through, and with an ignition and monitoring device having a Zündspannungsgenerator, an ignition electrode and a monitoring electrode and monitors the potential of the monitoring electrode relative to the burner tube or another at ground or ground potential counter electrode, characterized that the ignition and monitoring device ( 55 ) after the application of an ignition voltage ( 57 ) a smaller than the ignition voltage monitoring voltage ( 60 ) to the ignition electrode ( 29 ) and checks whether the potential of the monitoring electrode ( 30 ) from an initial value that it has no gas flame ( 59 ) and without ignition voltage ( 60 ) or monitoring voltage ( 57 ) decreases, to a reduced, but above the ground or earth potential value drops. Laboratory gas burner according to claim 16, characterized in that the monitoring electrode to an open input of an operational amplifier ( 62 ) connected. Laboratory gas burner according to claim 16 or 17, characterized in that the ignition and monitoring device ( 55 ) determines the value at which the potential of the monitoring electrode ( 30 ) to the application of the monitoring voltage ( 57 ) decreases. Laboratory gas burner, in particular according to one of claims 1 to 18, with a gas outlet nozzle, with a burner tube arranged in front of the gas outlet nozzle, into which a flow of a fuel gas emerging from the gas outlet nozzle entrains air in order to form a combustible gas mixture in the burner tube, the air passing through one of the gas outlet nozzle adjacent air supply opening passes through, and marked with a provided at its front with control and / or display elements housing, characterized in that at the back of the housing from a perforated plate section bent in a U-shaped Impfösenhalter ( 63 ) is provided. Laboratory gas burner according to claim 19, characterized in that the Impfösenhalter ( 63 ) a plurality of inoculation loops ( 65 ) at the free ends of their downward facing handles ( 66 ) in side-by-side tilted arrangement. Laboratory gas burner according to claim 19 or 20, characterized in that the Impfösenhalter ( 63 ) to the back ( 64 ) of the housing ( 2 ) is screwed.