DE1954426A1 - Method and device for testing gaseous atmospheres - Google Patents

Description

PATENTAKWXLTE

DR. E. WIEGAND. DIPL-ING. W. NIEMANN DR. M. KÖHLER DIPL-ING. C. GERNHARDT

MÖNCHEN HAMBURG

phone: 395 314 2000 HAMBURG 50, Oct. 28, 1969

TELEGRAMS: KARPATENT KONIGSTRASSE 28

w, 23973/69

Pilkington Brothers Limited, Liverpool, Lancashire (England)

Method and device for testing gaseous

Atmospheres.

The invention relates to the testing of gaseous atmospheres, for example those atmospheres which in the headspace or the top space of a glass melting furnace is present, and it is particularly concerned with testing gaseous atmospheres to measure the contents of the constituents These atmospheres can be used, which are insoluble or only poorly soluble in water.

It is known to test gas by that a probe is introduced into the atmosphere to be tested and a sample of the atmosphere is taken through the probe. Mechanical pumps are expediently used to suck off the sample through the probe.

These samples are under negative pressure, which can cause atmospheric oxygen to enter the sample is sucked into it. Such pumps therefore do not work satisfactorily in practice, if that is to be examined Gas contains corrosive agents or is at a high temperature. In the particular case of a stove like him

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is used, for example, in the manufacture of glass, • The exhaust gas temperature can be in the range of about 1600 ° C and furthermore, corrosive agents have a tendency to be introduced into the exhaust gases.

The main object of the invention is to provide a gas sampling probe which, among such works satisfactorily in difficult conditions.

According to the invention there is a method of analyzing an atmosphere with respect to a given gas which is insoluble in water, in that a sample of the atmosphere in a sample probe by means of a steam ejector pump

^ is sucked off, the pressure of the supplied water vapor is controlled in such a way that entrained atmosphere is at a pressure which is higher than atmospheric pressure, and the content of this gas in the entrained or entrained Atmosphere is determined.

The invention further relates to a gas sample probe which contains a sample tube which is a closed one has inner end, and which can be introduced into an atmosphere to be examined or tested, the tube near the inner end at least one side- ' Lent opening for communication with this atmosphere has, as well as a water vapor feed line, which ln the pipe extends and in the area of the side opening or

W openings ends in at least one ejector nozzle, which is axially of the tube and directed away from its inner end, whereby when the probe is working, water vapor which is fed to the feed line is sucked into the sample tube through the lateral opening or the openings due to the ejector effect.

A useful field of application of the invention consists in the quantitative testing or investigation of the oxygen content of furnace exhaust gases, for example the exhaust gases of an oil-fired furnace, as it occurs when melting glass batches is used. The oxygen content of the exhaust provides one

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Display of the combustion status in the furnace burners; at an automatically controlled furnace can measure the oxygen content of the exhaust gases, which is continuously examined, in a servo system with a closed working circuit usable for regulating or controlling the combustion of the furnace by controlling the air and / or fuel supply to it be made.

In a preferred embodiment of the invention the probe according to the invention is surrounded by the probe tube by a cooling jacket which has an inlet and an outlet for 'coolant or' a cooling liquid ', and the are spaced from the inner end of the sample tube. The cooling jacket preferably contains two coaxially arranged tubular walls, which inner and outer Determine passages of annular cross-section, these passages connected to one another at the inner end of the sample tube are, as well as corresponding coolant connections, polygons with the inner and outer passages at a distance connected from the inner end. The coolant, expediently water, can enter the cooling jacket along the inner passage enter and exit along the outer passage; however, if the atmosphere to be tested is on a is particularly high temperature, the coolant can circulate in the opposite direction and occurs along the outer Passage and leaves it along the inner passage.

In a preferred embodiment of a probe ends the water vapor feed line in the area of the lateral opening or openings in a nozzle block, the inner chamber has, which is centrally connected to the water vapor feed line, and which furthermore with a plurality of Ejector nozzles in connection, which in any ring-shaped Arrangement are arranged at a distance from one another and surround the V / asserdanipf feed line. Preferably the End wall of the inner chamber, v / which the steam feed

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Line and the ejector nozzles facing, formed concave, ■ to help remove the water vapor from the feed line to be directed against the ejector nozzles.

The nozzle block is preferably at least partially arranged opposite the side opening or openings of the sample tube, and the outer surface of the nozzle block opposite the or each of the openings is provided with a recess in order to provide a gap between the nozzle block and the inner surface of the tube at the or at each lateral opening To create space.

To prevent the ejector nozzle or nozzles from being blocked to avoid and to reduce the possibility of condensation which can occur within the probe is preferred the steam feed line is supplied with steam by means of a filter and a dryer.

To shut off the flow of water vapor and the entrained gas through the sample tube is preferred a shut-off valve is provided, whereby when the valve is closed, water vapor emerging from the nozzle or nozzles through the side opening or openings passes through. By these means, corrosive accumulations, which otherwise the ejector nozzle or the ejector nozzles are or the side opening or the side openings would clog over time, by the outward flow of water vapor through the side opening or the side openings cleaned. In an automatically controlled furnace, means for automatically closing the shut-off valve may be provided during predetermined intervals at separate times during the operation of the probe.

A preferred embodiment of the Finding explained in conjunction with the drawing, for example.

Fig. 1 is a schematic axial cross-section through a gas sampling probe according to the invention.

Fig. 2 is an axial cross-section, on an enlarged scale

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of the nozzle block, as it is with the probe of the Pig. I. is used.

Pig. J is a cross-sectional view taken along line III-III

1 of the probe on an enlarged scale, and

Fig. 4 is a schematic representation of a gas analyzer, which uses the sample probe of FIG.

According to FIG. 1, the gas test probe shown, which generally indicated by 1, inserted through the wall of a furnace such as an oil-fired furnace of that type which are used for melting batches for supplying molten glass to fiberglass pullers in the Furnace atmosphere is used, which furnace atmosphere contains the combustion products of the furnace.

The probe 1 contains a sample tube 2 which is closed at its inner end and which at the left side of Fig. 1 is shown, and which in the to be tested Atmosphere is introduced. Near the inner end is the tube 2 with side openings 5 (in the present example two in number), which with the exterior of the Probe 1 (i.e. with the atmosphere to be examined, which is checked when the probe is used) by corresponding laterally extending inlet pipes 4 (Fig. 3) in connection stand.

A water vapor feed line 5 extends coaxially within the test or sample tube 2 and ends in the area of the lateral openings j? in a nozzle block 6, which is shown in detail in Figures 2 and 5. The nozzle block 6 has a generally cylindrical outer surface and fits into the sample tube 2, and the block 6 extends at least partially over the side openings. The outer surface of the nozzle block 6 itself is provided with two parallel flat surfaces 7 in the form of recesses (Fig. 5) » which are arranged opposite the corresponding openings J in order to create spaces 8 between the nozzle block 6

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and the inner surface of the tube 2 to the corresponding to create openings 3.

The nozzle block 6 is made of two parts, which a nozzle plate 'Io and a cap 11, both of which are formed from a heat-resistant and acid-resistant alloy are, for example an alloy known under the name INC-OLOY 825. The plate Io has one in axial direction extending circumferential flange 12, which with Internal thread is provided, and one with external thread provided part of the cap 11 receives. An annular seal 14 made of copper is between the face and the

fc Plansch 12 is provided, and is an axially directed surface provided on a flange formed on the cap 11.

The water vapor feed line 5 stands with a middle Inlet 15 in the nozzle plate Io in communication. The surface of the cap 11 is immediately opposite the plate Io against the plate Io and around the axis of the inlet. 15th symmetrically concave, so that an inner chamber 16 is formed within the nozzle block 6. The nozzle plate Ip is provided with a plurality of ejector nozzles, which bores 17 extending in the axial direction in of the plate Io, which are arranged in an annular shape and surround the inlet 15 concentrically and with the chamber 16 in

"Connect.

The sample tube 2 is coaxially surrounded by a cooling jacket, which has an outer cylinder wall l8 and a cylindrical one Contains partition wall 2o which is inserted between the wall 18 and the pipe 2. The inner end of the wall 18, i.e. the end which is introduced into the atmosphere to be tested can be is closed and from the closed interior End of the sample tube 2 spaced while the inner end of the partition wall 2o is open and spaced from the closed end of the wall 18. Inner 'and outer coolant passages 21 or 22 of circular or ring

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shaped cross-section are thereby created between the wall 18, the partition wall 2o and the outer surface of the pipe 2, the two inlet pipes 4 extending through the passages 21, 22 extend therethrough and protrude a short distance outwardly beyond the outer surface of wall 18.

The corresponding coolant passages 21, 22 are closed at their outer ends and stand with them laterally extending outlet and inlet pipes 2j5, 24 for the coolant in communication. The test or stands in a corresponding manner Sample tube 2 at its outer end with a lateral sample feed line 25 in connection.

When working, the probe 1 is placed in the furnace atmosphere to be tested through a suitable seal in the furnace wall e6j introduced, as shown schematically in Fig. 4, so that the side inlet pipes 4 are placed in the atmosphere, during the various connections to the probe 1 are arranged outside the furnace wall 26v%.

Steam is fed to the steam feed line 5, enters the chamber l6 of the nozzle block 6 and passes through the bores 17 of the nozzle plate Io as one Plurality of rays that oppose in the axial direction the outer end of the sample tube 2 are directed. The reversal of the direction of movement of the water vapor flow in the Chamber 16 is defined by the concave inner surface of cap 11 supports. The ejector effect caused by the water vapor jets a pressure reduction at the side openings j5 near the nozzle block β, and as a result, gas is released from the Oven atmosphere withdrawn through the inlet lines 4 and the side openings 3 "

The water vapor that mixes with the gas under test is, migrates outwardly along the sample tube 2 and enters the line 25. The line 25, which is a shut-off valve 2β contains, conducts the water vapor and the gas mixture into a condenser 27? v / o the mixture comes into contact with pipes through which cooling water circulates. The water vapor

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is condensed in the condenser 27 and is passed through as water along with any entrained pest particles an exhaust outlet 28 led away.

The gas sample is made after removing the water vapor from it. in the condenser 27 passed through a filter device j5o in order to separate pesticides from the gas. The filter device j? O expediently contains two filters ■ of the ⁿ Pall-Type ", many are each connected in parallel power lines, so that each filter after the flow has been shut off through the corresponding flow line.

. device can be replaced without the gas flow through the Interrupt filter device 3 ° in total.

After passing through the filter device 3o, the gas sample passes through a flow meter J> 1 to an analyzer j> 2, in which the content of a particular gaseous component insoluble in water, in this case oxygen, is continuously measured. Any known analyzer The combustion conditions of the furnace burners can be determined by measuring the oxygen content in the furnace exhaust gases. However, the analyzer 32 can be operatively associated with a closed-loop servo for controlling the fuel-air ratio of the furnace burners so as to automatically control the burners maintain a predetermined oxygen content in the furnace exhaust gases.

It is important that the water vapor supply line 5 supplied water vapor is dry and free from impurities. The water vapor supply line 5 therefore preferably contains Filter 33 and a water vapor-water separator or Dryer 34, known under the trademark "SPIRAX". ·.

"-.-; - 'While the coolant for the probe is working expediently circulated water in the cooling jacket. In the example shown, the coolant fed through inlet conduit 24, travels through outside.

.the outer flow line or the passage 22, reverses

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through the inner flow line or the passage 21 and the outlet line 2j5 back. This direction of circulation of the coolant is preferred in practice when the furnace exhaust gas temperature is of the order of magnitude of 160 ° C or higher is "

Because of the high working temperature of the probe, its exposed parts, especially the cooling jacket wall l8, Made of a refractory alloy and preferably contains pure "5T" stainless steel. Share, 'which the same applies to the steam and furnace exhaust condensate when working are made of an acid-resistant alloy, for example an alloy that is exposed to the Name INCOLOY 825 is known; such parts contain the Nozzle block 6, the water vapor feed line 5 (at least its inner end) and the sample tube 2.

When working with probe 1, corrosive (acidic) Products tend to condense on the exposed surfaces of the probe and would in the course of the Time the inlet lines 4 - and the side openings 3 clog and corrode. To .an unwanted- · accumulation To prevent these parts, the shut-off valve 26 is periodically closed for short periods of time, for example for a few minutes every 24 hours. This has the effect that the water vapor gas outlet from the probe 1 is blocked, and .this causes water vapor, a.from the nozzle block 6 through the openings 3 and the lines 4 blow through, thereby eliminating buildup in the latter parts. The valve 26 can be done by hand can be actuated, but can optionally be actuated by a solenoid and for a predetermined time interval be closed automatically with prior determination.

In order to further reduce the accumulation of condensates on the probe 1, the latter is preferably arranged in such a way that that they are in the oven with a bevel upwards

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COPy

1 95A4 26

extends, for example at an angle of about 15 ° to the horizontal, as shown in Fig. H- is shown.

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Claims (10)

Claims. (l. Method for analyzing an atmosphere in relation to on a given gas which is not soluble in water, characterized in that a sample of the atmosphere in a sample probe by means of a steam ejector pump is withdrawn, the pressure of the steam supply line is regulated in such a way that entrained atmosphere is at a pressure higher than atmospheric pressure, and the content of the gas in the entrained atmosphere is determined. 2. Gas sample probe for performing the method according to claim 1, characterized by a sample tube which is a has closed inner end and is insertable into the atmosphere to be tested, and the tube near the inner end to connect with the atmosphere at least one side has opening, and a water vapor feed line extends into the pipe and in the area of the side opening or the opening ends in at least one ejector nozzle, Many are directed axially of the tube and away from its inner end, thereby causing the probe to operate Feed line supplied water vapor atmosphere through the side opening or into the openings through an ejector • effect sucks into the sample tube. J. Probe according to claim 2, characterized in that the tube is surrounded by a cooling jacket which has an inlet and an outlet for the coolant, which from are spaced from the inner end of the sample tube. 4. Probe according to claim J5, characterized in that the cooling jacket has two axial tubular walls which have an inner and an outer passageway of annular Determine cross-section, and these passages at the inner end of the sample tube in communication with one another stand, and coolant connections are provided, which 00982G / 147 1 BATH ORIGINAL with the inner and outer passages spaced apart by connected to the inner end. 5. Probe according to one of claims 2 to 4, characterized in that that the water vapor feed line in the area of the side opening or openings in one Nozzle block ends, which has an inner chamber that is centrally located with the water vapor feed line and further with a plurality of ejector nozzles in communication, which is in the distance from each other in a ring-shaped .. order and the water vapor Surrounding feed line. 6. Probe according to claim 5 *, characterized in that the front wall of the inner chamber ,, ... which the water vapor W feed line and facing the ejector nozzles is concave. 7. Probe according to one of claims 5 or 6, characterized characterized in that the nozzle block is at least partially opposite the lateral opening or the openings of the Sample tube is arranged, and the outer surface of the nozzle block opposite the opening or openings with a recess is provided to between the nozzle block and the inner surface of the tube at the side opening or the Each opening to create a free space, 8. Probe according to one of claims 2 to 1, characterized in that the water vapor feed for the water vapor fc line a filter and a dryer are provided so that the steam supplied to the feed line is essentially free of particles and water. 9. Probe according to one of claims 2 to 8, characterized in that that a shut-off valve is provided, which with the sample tube to shut off the entrained by the tube Water vapor flow and the gas is in communication, whereby, when the valve is closed, water vapor passes out of the nozzle or the nozzles through the lateral opening or openings. 10. Probe according to claim 9 »characterized by a 009826 / U71 BATH ORIGINAL _ ■■■■ · _ - 19 5 4 A Automatic shut-off device for the shut-off valve at predetermined time intervals during work the probe. 00 98 26 / U7 t Blank page t-e