DE7411979U - Pre-filter for taking and preparing samples to be analyzed - Google Patents

Description

Engineering office for environmental protection measurement technology, owners ι lillmann Knapp and Roland Zepeok 8000 Munich 80, Wörthetraße 26

Yoxfiltex for taking and preparing samples to be analyzed

The invention relates to a Yorfilter for taking samples and preparing samples for an analyzer » with filter and heated sampling line.

A peat filter is known in which the filter insert is made of fiberglass and in which the sample line exiting the peat filter passes through the heating element a steel block arranged around the sample line and filter is heated. Sine temperature control takes place with a bimetal switch based on the temperature measured in the block.

The known device does not enable the temperature to be precisely maintained at a desired value of 180 ^{° C., for example.} On the other hand, the sample should be in the emission temperature range of diesel

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motors - approx. 18ü ° C - are kept so that not a number of high-boiling hydrocarbons in the cold Condensing the pipe · On the other hand, a good filter result is very important, so that the sensitive Analyzer is not damaged.

Such a pre-filter should now be proposed, for the first time a precisely controllable constant temperature maintenance with automated change of the filter insert for better measurement results long tent spaces to get accurate and repeatable measurements.

According to the invention, this is achieved essentially at a filter of the type mentioned in that the actual filter and the sample line in the are essentially heated together by a closely spaced heating coil and that the filter is a cylindrical one Filter candle made from sintered pellets with pore diameter knives in the range of 2yu contains

A bimetallic pointer is preferably gas-tight provided on the filter housing wall, the shaft of which dips into the sample line on the filter.

They are useful for the possibility of backwashing of the filter a backwash connection with protection valve and a Umsohaltsmagnetventil provided ^ through which the sample & frame system in one direction opposite to the direction of the sample let rttokspttlen with compressed air.

Preferably a Siohgasansohlufi is provided that

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a solenoid valve is applied in such a way that the entire

Unit - and not just the analyzer as before - I.

can be calibrated.

Fans are advantageously arranged directly above the magnetic coils, with the valve bodies the solenoid valves of the hot coil are in contact.

Compared to the known filter insert made of glass wool, a filter cartridge made of sintered material is now used stainless steel with heat and higher currents anti-ductile and anti-magnetic properties.

The compact design contributes to the fact that the unit is designed as an insert in an outer housing.

The object mentioned at the beginning is fully achieved by the invention. It is possible to work with a significantly increased work sequence, since the hot coil can be kept on during calibration and backfilling and the maximum temperature of approx. 18Θ ⁰ is reached again within a very short time when switching to dropping.

Your entire leg work is thus automated. The results obtained according to the invention are powers of ten better than with known devices, in which only the analyzer was signed.

Sa the pollution of the entire facility up to su Can amount to £ 30 of the measured value, it is crucial that The filter and sample line must also not be matched know where, for example, the pollution is 15 ppm with a measurement around 200 ppm bought

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Surprisingly, the measure according to the invention the coil of the solenoid valves to approx. 60 °, the valve » bodies, on the other hand, are kept at 180 ° e. »This contamination, which defies all caution in the sampling system and fix it in the analyzer, are now included in the self-value, which is a falsification of the measured values excludes. Due to the backwashing option of the filter longer service life of the filter material will be is enough, the time required for cleaning is significantly reduced and the cleaning itself is significantly simplified.

The entire pre-filter is extremely small in its dimensions.

In addition, the temperature of the sample gas stream can be ^{freely selected between room temperature and 200 °} C. and set on the prefilter. The sample path in each pail leads exclusively through the heated chamber.

If there is no compressed air available for backwashing, a backwash pump can be used.

The pre-filter according to the invention can be used as a sampling system switched in front of all commercially available Aa & lyzers the gaseous pollution in exhaust air and outside air, d. H. Emissions and immissions, measure up.

The pre-filter can be fitted with pipes made of stainless steel, Monel, titanium, aluminum, brass, copper, quartz glass as well as hoses made of polytetrafluoroethylene and poly-

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Sas peat filter can be made of brass, Stainless steel, monel, aluminum and titanium can be provided.

According to special training forms, an additional three / two-way solenoid valve can be installed in front of the calibration gas connection au calibration solenoid valve for supplying bichgas and enveloping gas can be provided in order to zero the analyzer including the whole To determine the sample identification system.

An additional solenoid valve can be installed between the sample inlet and the calibration solenoid valve can be provided in order to obtain a separate output for the Bttokspttlluft. In this case, the return output would not be the same Receipt of samples.

The Yorfilter is also parallel for several sample streams to interpret.

Sine, for example, embodiment of the invention will now be explained in more detail with reference to the accompanying drawings, in which s

FIG. 1 shows an embodiment of the invention in FIG Perspective shows;

flg. 2 shows a top view of the in Pig. 1 ge

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- 6 showed device, but without housing;

shows a plan view of the essential cables of the device, but without a fan and without a cover for the heated chamber;

shows the embodiment from the rear;

shows part of the MaB-nahae according to the invention; and

shows a detail of the temperature measurement.

The exemplary embodiment of the invention shown in FIG. 1 is combined as a compact unit in a housing 24. For example, the unit loads itself, without ftmÄ further measures would be necessary to which Unscrew or screw on the exhaust line of an engine connect to this. For example, the dimensions of the device shown in FIG. 1 are 230 mm wide; Height 190 mm; X depth 210 mm. Ss could weigh only 6 kilograms can be achieved. The device is provided with handles 32 for better handling. In the The front panel are operating and monitoring elements arranged as switches 21, signal lamps 23 and fuses. Sas for the purpose to be described below important temperature measuring device is in the form of a bimetallic display thermometer 12 placed in the front panel 22. Despite the high operating temperatures, this can be done Handle the device without endangering the user.

The structure of the device should be based on the achematic Fig. 2,

3 and 4 are briefly explained ι

The device consists essentially of a later filter 6 to be described in more detail, with regard to this its construction has been chosen so that it relates to practically for the first time a shark has a Rüok-Bpül option results. The filter 6 is of a :? Surrounding heating coil 30. You heat performance is by means of controlled by a healing conductor arranged in the sample gas flow itself, namely via a no longer detailed here electronic temperature gel unit 20. An The filter is connected to lines that lead to a backwash solenoid valve with magnetic coil 8 and once Vent liqueur per 9, on the other hand to an egg.hmagne-cvontil drive with valve valve 4 and valve body 5. Sas calibration solenoid valve is connected to a fiiehgasansehlue 34 via a line designated 35. Sas solenoid valve 6-9 via a pre-filling air line 37 with a Air supply 36. Between the supply of air and the line 3? is a Sohutz solenoid valve 16, which is provided for the VaIl, AaJ with Stromauefall the compressed air reservoir is blocked. Bs could it can be achieved that all connections - if required - lead out to one and the same front panel becoming

Like fig. 2 more precisely IiSt are two fans provided, which cool the coils of the solenoid valves 8, 9 or 4-5 and the temperature control unit.

Adjusting screws 26 for temperature protection switches are designed to be accessible from the outside.

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On the one hand, a constant temperature at the filter lind the sample line, on the other hand the To protect the remainder of the device against heat, a cover 28 is provided with a cover (not shown) above it Isolation provided. Inside the cover are bimetallic circuit breakers 26 for temperature control intended. The feed lines for the solenoid valve 8-9 are denoted by 38.

In contrast to the usual ones in the field filters with glass wool and ceramic inserts, which are necessarily larger in size, become one according to the invention Special filter unit 6 - fig. 5 - used, which consists essentially of a cylindrical filter candle 40 consist of sintered pellets. The pellets are sintered in such a way that the pore diameter is about 2 yu. A stainless steel is chosen as the material, which is neither ductile with the small pore diameter still acts magnetically, not even at high flow velocities. The through-flow is indicated by arrows of the filter in Pig. 5 specified. During assembly, the filter candle 40 is screwed onto the housing end piece 44. The whole thing is then screwed against the filter housing.

An important detail relating to the temperature display is shown in FIG. 6. In contrast to the very expensive electronic temperature measurement within a heated gas flow, which for this reason seldom so far According to the invention, a bimetal dial thermometer is carried out 12 provided in the T-piece 10. The fastening is gas-tight. The shaft 48 dips into the sample gas line in the T-piece 10; the display device 12

on the other hand is found outside the front panel 22. The Implementation through the housing is carried out by means of a son ring screw connection The arrangement by means of a son ring screw connection in the T-piece 10 guarantees gas tightness. A temperature is therefore not measured indirectly outside of the gas flow, as has been the case up to now, but directly the temperature of the guest flow.

The proposed device allows the following functions:

Coming from the engine test gas can be continuously filtered in the filter and are held at the same positive effect on a displayed temperature such as 180 ⁰ Q. In the filter, the unwanted particles z. B. & uß, retained, namely all particles whose grain size is larger than 2 / u. By this accurate temperature maintenance, it can happen nioht that remain, for example, below 180 ⁰ C, or the like acids condenses out on the walls of the filter stick. The analyzer is now subjected to a gas that has been cleaned better than before and a gas whose temperature can be guaranteed.

Also in contrast to previously known filters, it is due to the use of the one described with reference to FIG. 5 Special filter possible to carry out a backwash. For this it is only necessary to use the backwash magnet valve to turn on. The direction of flow is then opposite to that in fig. 3 for example drawn. The duration of the backwash is about 1 minute. The big advantage here is that you do not have to wait until the filter or the device has cooled down. The heat-up time is in contrast for the hitherto necessary complete replacement of the

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filters much shorter, since with the Heiaswendel during of the Rüokspulvorganga is continued. You wake up time is about 1 to 2 minutes.

In previous devices, there was a biohythmia for the analyzer was made available «but falsifications in the measurement had to be accepted because the sample sewing system or the pre-pilter and whose degree of soiling was not included in the calibration. This can be done with a separate connection Device by means of a Xüchgaaes only by relocating a single so holder of the calibration solenoid valve can be calibrated. The direction of flow is then the same as the direction of the sample gas flow.

This works according to the exemplary embodiment Device as follows t

Ser sample inlet 2 is exposed to a sample gas to be cleaned, for example, coming from the engine test unit; (flg. 4). Sureh the aforementioned heating coil with 4 enrähnten temperature control is the sample gas up to the sample 14 z. B. kept at IOP ⁰ · Should it have a lower temperature, it is heated in the area of the filter by the heating coil 30 with a jacket made of V4A steel. Meflwertverfälsohungen are avoided by maintaining the temperature.

The sample path in the pre-filter is the following tom sample inlet 2 the gas to be treated flows through the valve body 5 and goes into the special filtering 6. This is as in TIg. 5 shown

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represents assertive. There are solid and dusty substances that are larger than Z yes. are, tt d filt

Sample gas exits the filter, through the filter body 9 of the BÄokspttlmagnetventlls and arrives at a pipe branching, a T-piece 10. The sample gas passes the shaft 4Q of the bimetal dial thermometer 12 to the sample outlet 14 · The line, into which the shaft 43 of the thermometer is immersed , lies closely above the heating coil for reasons of influencing the temperature. The sample gas path between the TentilkSrper 9 and T-piece 10 is placed close to the helix 30. At the outlet from the valve body ρ er 9, the temperature is sampled, for example with an NTC resistor; If necessary, the Heisvsndel will be increased if the temperature has fallen below the setpoint. It is essential that the valve bodies 9 and 5 can be arranged close to the heating coil by the solution found, and that the functionality of the solenoid valve is still not impaired by the cooling provided by the fan 18. The vertical bodies 9 and 5 lie directly on the heating coil 30 according to the execution * - example.

The bridge flush solenoid valve 8-10 is used for rewinding switched. Ss is a three-way valve. Pre-air now flows through from the prefil air outlet 36 the filter 6, namely in Ricktang opposite to that of the sample gas flow to the sample inlet 2. Sas filter is cleaned of stubborn dirt. Sa « Calibration solenoid valve 4-5 is on position "Profce *, tie heating coil 30 continues to heat. Further changes are not required. This closes in the event of a power outage

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Cover solenoid valve 16; there can therefore be no loss of compressed air enter. This function was the usual one up to now Use of glass wool as a filter insert is not possible. The entire filter insert must be removed ©, which was only possible after the device had cooled down.

During the calibration process, the Eiohmagnetventil 4 - 5 is switched in such a way that the connected safety gas via the Bichgasanschluss 51 through the filter 6 to the sample 14 can stream. The self-gas is, for example, a defined polluted gas. So there is a common calibration of the pre-filter, Sample feed line and analyzer. Bas backwash solenoid valve 8-9 is in the "Trial" position. Through the process of being it is achieved that dirt that is despite all caution in the sampling system and in the analyzer set, are included in the calibration value and thus a measurement falsification is excluded.

Contamination that may be in the sampling system or are located in the analyzer or in the sample feed line, are therefore included in the self-value and are taken into account in the analysis value.

! The Eonstanthaltung the sample temperature to 18o ° and temperatures in a part of the apparatus, prior to babble things in the solenoid valves (a., 180 °) on the other hand, the temperature maintenance of the solenoid valves 60 ⁰ G or less at the tightened magnet succeeded in that the fans are arranged within the housing directly above the coils or components to be cooled. This was also achieved by using the insulating

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material an Aabest foam material of high quality yerwejxdot vurd ·.

The prefilter can also be operated by an operator, the one with the pre-filter duxoh a remote control cable verbuEdsfi is and aämtliohe in sturdy armored conduit Contains control and safety equipment.

Use of the pre-filter, undo heated, for water analyzing inalysatoren, whereby the Bttoksptttlung done with compressed air or acidified water is also possible

Expectations

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Claims (1)

- 14 - 1. Yorfilter for sampling and processing τοη samples fttr an analyzer old filter and heated frosting line _y daduroh marked that the actual filter (6) as well as the sample line (2-14) essentially together by a closely adjacent helix ( 30) heated and the filter contains a cylindrical filter candle (4G) made of sintered pellets with Psvendurolimeasern in the area τοη 2yu. 2. Yorfilter naoh claim 1, characterized by a bimetallic Zelger thermometer (12) on the filter housing wall, its shaft (48) in this bottle line (at 10) on the filter (6) tauoht. 3. Yorfilter according to one of the preceding claims, characterized in that solenoid valves (4- 5 »8-9) are provided for calibration and return function with their Yiintilkerpern (5J 9) the heating coil (30) are applied, with the magnet coil ^. (4l 8) Yentilatoren (18) are arranged. 4 · Yorfilter according to claim 3 » characterized by a compressed air inlet (56) with an associated protective solenoid valve (16) arranged on a Q-housing faceplate, from which a prefil air supply (37) leads into the solenoid valve (8-9) associated with the filter (6). 5 · Yorfilter according to one of Claims 1 to 3, characterized by one on a crehftus face plate = 15 - - 15 - arranged EichgasanschJufl (34), τοη the one Eiehgaazufführung (35) leads into the egg chmagnetvant.il (4-5) upstream of the filter (6). 6. Pre-filter according to claim 1, characterized in that the filter cartridge (40) is made of sintered stainless steel Steel with at Wime and higher flow-drilling possibilities anti-ditktile and anti-magnetism Properties. 7. Torfliter according to one of the Torher claims, characterized in that dl :? Unit as compact insert iß an upper housing (24) is. 8. Torfliter according to claim 5 _t characterized gekennseiohMet that a Breiwegmagnetventil is arranged to determine the zero point of the analyzer uad sample line gate to the Elchgasansohlufi. 9. Gate filter according to one of the gate claims, characterized by »that for the separation τοη flushing outlet and Sampling ^ ang a solenoid valve is upstream of the solenoid valve. 10. Gate filter according to one of the preceding claims, characterized in that several parallel lines are provided for several sample streams are. 11. Gate filter according to claim 1, characterized in that that the helix (30) is placed around the filter (6) and that - 16 - the sampling line is passed close to the helix iat. - 17 -