EP2404152A2

EP2404152A2 - Analysis methods and analysis apparatuses for fluids

Info

Publication number: EP2404152A2
Application number: EP10716614A
Authority: EP
Inventors: Markus Dantler
Original assignee: Individual
Current assignee: Individual
Priority date: 2009-03-05
Filing date: 2010-03-03
Publication date: 2012-01-11
Also published as: DE102009011846B4; US20110314902A1; US8813540B2; WO2010100549A3; DE102009011846A1; WO2010100549A2

Abstract

The invention relates to novel methods and to devices for a measuring and analysis apparatus that measures impurities and/or particles in a gas or air. In a particle separation step, target particles having predetermined particle properties are separated from remaining particles from a gas or gas mixture such as air or a liquid, in short a fluid, that contains a particle mixture, and the occurrence and/or frequency of said target particles is determined in a measuring chamber. The likewise novel cooling of the radiation sources required for measurement permits the use of such having high power, as is required for measuring few particles or the smallest impurities. A further novel expansion of the electrical measurement range allows small but also abundant particles and impurities to be measured. In addition, a novel interface simplifies the start-up of the apparatus.

Description

Analytical methods and devices for fluids

DESCRIPTION

Technical area

This invention relates to novel methods and corresponding measuring and analyzing devices which are contained in a fluid, ie a gas, gas mixture, e.g. Air or in a liquid impurities or particles measure. On the one hand, the invention relates to a method and an arrangement for particle separation, wherein in a gas or a liquid containing a particle mixture, target particles having predetermined properties are separated from residual particles. The target particles themselves are analyzed or measured. In addition to the particle separation in measuring and analysis devices, the invention allows by a novel cooling the use of radiation sources with very high power, as they are necessary for the measurement of a few particles or smallest impurities. An extended electrical measuring range allows the determination of small but also larger deposits of particles and impurities. In addition, a novel user interface simplifies the commissioning of such devices.

Background and state of the art

There are a number of problems with the existing contaminant particle measurement and analysis devices in a fluid, i. a gas, gas mixture or a liquid and the corresponding measurement and analysis methods.

A first problem area concerns particle separation or particle separation. In various applications, for example, only particles with a certain size of importance and only these should get into a measuring chamber, ie the initially existing particle mixture must be separated according to certain particle properties. This particle separation proves to be difficult, especially when it comes to mixtures of microscopic particles. This is explained by some examples.

Often in industrial, technical but also biological or medical examinations, e.g. In diagnostics, occurring object is the separation of gases or suspension mixtures by distribution or sorting of microparticles from a large initial amount into specific groups, each having the same properties. If it is possible by means of particle separation or particle separation to supply only the desired target particles to the measuring chamber or the measuring range, this has the following advantages:

1. Increasing the reliability of the device due to less or no erroneous measurements by particles that do not correspond to the target particles. 2. Extension of the service life of the device due to the reduced or prevented contamination of the optical measuring / analyzing device by larger particles.

3. Simplification of the device since protective components, e.g. Filter, or measuring components, which measure the larger particles, can be omitted.

In an exemplary application, the detection and measurement of the smallest amounts of fire aerosol particles is considered, as occurs in so-called intake smoke detection (ARM, Aspirating Smoke Detector, ASD). Here air of the room to be monitored is sucked in via a pipe system. This pipe system consists of one or even several tubes and is in the total length usually between 10m and 200m long. It has at a distance of about 4m suction openings of a diameter of about 2-6mm. Thus, for example, a warehouse, an IT data center, a production area or an electrical switchgear, etc. can be monitored. The measuring chamber in the device then measures the presence of fire aerosol particles and gives an alarm when a certain preset value has been reached.

Brand aerosol particles have a size of about 0.01 - 10 microns (microns). Smaller particles would be e.g. Viruses and larger dust. In order to detect even the smallest amounts of fire aerosol particles, a highly sensitive measuring chamber is needed. Here, radiation, e.g. Light from a light source, delivered in a detection area. If such small fire aerosol particles are present in this area, they scatter the light. This effect causes either a light turbidity (transmission measurement) on a photoelectric sensor, because then less light occurs, or by the light scattering only light reaches the sensor (reflection measurement). With one of these two principles, the fine particles are detected. As the radiation source, a light emitting diode (LED), a laser diode (LD), a xenon lamp or the like can be used. In the measuring chamber, other components, e.g. optical lenses, one or more photoelectric sensors and / or an amplifier circuit are located.

Another way of detecting fire aerosol particles is to use an ionization chamber.

Hereinafter, by way of example, currently used methods and devices will be described as examples of particle separation. It should be explained that the term "particle separation" here means the separation of the particles according to predetermined particle properties, whereby the separated particles also remain in principle in the fluid, ie in separate volumes of the fluid. By contrast, the term "particle separation" is understood to mean the removal of the undesired particles from the fluid.

One method is sedimentation by gravity, centrifugal force or redirection as e.g. used in cyclones. Here, the devices are relatively large and usually expensive to manufacture, which limits their use as wall or table units. In addition, particle deposition is not good enough in certain applications and especially in the micrometer range. The problem lies here in principle, since a separation of particles for the measurement is actually not necessary. Only these or certain particles may not reach the measuring range, but they may remain in a current outside the measuring range. These devices intend to separate the particles from a gas, and thus all the fluid would subsequently be free of these contaminants. Larger particles can remain in the main stream. It is sufficient if the fluid is diverted only a small amount, which is free from impurities. Particle separation or precipitation is not necessary at all and thus, for example, emptying and cleaning the cyclone or a filter replacement, etc.

In an electrostatic deposition, the particles are electrostatically charged and deflected in an electric field. Disadvantages here are the additional necessary electrical components and the moisture sensitivity of this variant, which limits their use.

In a particle separation by filters, eg filter mats, fabric filters, etc., larger particles are penetrating into the device or in the Measurement chamber withheld. One disadvantage of such filters, however, is that they cause a pressure drop. The suction device, such as a fan, therefore, must be designed according to more powerful, which in turn attracts a higher energy demand. Another and much more serious disadvantage of these filters is that they become more and more clogged with the retained particles during operation. MaW, less and less of the target particles to be measured can pass through the filter. In extreme cases, a clogged filter prevents the desired target particles from even reaching the measuring range. In a fire detector, as described above, then the fire aerosol particles, which are actually to be measured, no longer flow into the measuring chamber. In case of danger, such a device would detect only insufficient or nothing at all, ie the fire detector would not report anything. This requires a regular filter exchange, since a clogging of the filter and thus the Blackade of the inflow into the measuring chamber can not be predicted.

As another possibility, the occurrence of undesired, e.g. larger particles can also be determined by means of an additional, for example, optical measuring method. The disadvantage here is that the measuring chamber is contaminated especially by the larger particles, more electrical components are needed and the setting and calibration of the device is associated with additional effort.

Alternatively, the fouling of the measuring chamber can also be accepted and electrical or electronic measures used to correct the measurement results. If the measuring optics picks up particles during operation, ie dusty, their sensitivity is reduced. To compensate for this, the sensitivity of the measuring system is electronically corrected or readjusted. This electronic readjustment is called "drift compensation". For example, over time the Speech behavior designed more sensitive, since it is assumed that the optical components (dirt) receive particles, so less light enters the measuring chamber and the measuring sensor. Whether pollution actually arises or whether it is stronger or less, is irrelevant to the so-called "planned", ie pre-set compensation. However, this results in the serious disadvantage of this drift compensation, namely that the measurement behavior and thus also the response of the device, eg the fire detector, changes in the course of operation and this change does not correlate with the actual sensitivity or the degree of contamination.

Some of the methods mentioned are described using the example of a fire detector in published patent application WO 2005/043479 A1. There is e.g. a method is described how a distinction of the particles can be made according to their size.

Published US patent application 2009/0025453 A1 describes a smoke alarm and the corresponding method in which a side stream with smaller particles is branched off from a main stream by dividing and accelerating the main stream into two part streams. The greater inertia of the larger particles makes them fly straight on, while the smaller particles are more easily deflected into a side stream. This mechanical principle of inertia / gravity separation, which is known per se, is used here, inter alia, in a smoke damper in such a way that an air flow in a nozzle arrangement is accelerated. An inlet located in the center of the nozzle, which has a negative pressure, sucks in the smaller particles and thus causes the separation. However, the design of this device is very expensive, especially since the Absaugvorrichting is disposed within the nozzle and forms part of the same. Also, it is not clear how the construction shown should prevent reflected larger particles from being flat. if they get into the secondary flow intended for the investigation. The following problem areas are not addressed in this US patent application.

A second area of concern concerns particulate deposits in the measuring chamber, in particular on the measuring optical or electronic devices. These devices are in an area that is separate from the medium, i. the gas or liquid is flowed through. As soon as additional parts or the necessary openings are inserted into the measuring chamber or the flow area, e.g. Lenses, sensors, radiation sources, etc., create unevenness such as joints, openings for the radiation source or the sensor. These result in turbulence of the flowing medium, which in turn leads to deposits of particles in mostly undesirable places.

If such deposits form on the optical components, in particular on or on the radiation source, this has the consequence that less radiation emitted by the radiation source reaches the measurement area. This alone distorts the measurement. The same applies to the sensor. Beat on its surface or its components, e.g. Lenses, particles down, thus reducing its sensitivity and thus its ability to korrkor measurements allow. M.a.W., a particle deposition prevents the desired flawless measurement.

A known method for preventing this is to filter virtually all particles, including the target particles, out of the medium by means of a separate upstream fine filter and thus virtually to produce a pure fluid. This then flows both via the radiation source and via the sensor; It prevents particles from precipitating on these two parts or in their areas. Later, this pure gas gets back into the main stream. The disadvantages of a filter have been before explained. Its degree of soiling and clogging can not be determined, and therefore not when the filter clogged and thus the gas / air supply is reduced or blocked in the measuring chamber. For example, the consequences can be fatal for a fire detector if a fire hazard is detected too late or not at all.

The present invention has set itself the task, the o.g. Disadvantages of the known methods and devices in relation to the first problem area to avoid and to ensure a simple and reliable separation of the measurement of certain particles in a fluid. This object is achieved by means of measures and devices as defined in the patent claims, with advantageous embodiments and applications of the invention being apparent in particular from the dependent claims.

The particle separations according to the invention described below are improved separation processes which are distinguished by high throughput, high selectivity and cost-effective production and avoid the disadvantages of the above-mentioned present-day processes. The same applies to the disclosed separation devices for implementing such methods.

With the particle separation according to the invention, furthermore, the abovementioned problem of deposits in the measuring chamber, in particular on the optical or electronic devices used for the measurement, is eliminated or at least reduced. The separation generally reduces the particle content of the medium to be measured, which generally prevents the penetration of larger particles into the measuring range and reduces the contamination of the components such as the radiation source and / or the sensor. The possibly still depositing, smaller target particles represent a significantly lower impairment.

A third problem area in the measurement and analysis methods and devices discussed here relates to the light or radiation source which is arranged in or on the measuring chamber and with the aid of which the actual measurement is carried out. This radiation source must emit a corresponding power, for example emitting light in the visible range, in order to enable the detection and measurement of very small amounts of very small particles. The problem here is that the radiation source must provide a high radiant power and this as constant as possible over a long service life. For this purpose, operation in a corresponding, narrow and usually low temperature band is essential. Only in this way can it be ensured that the maximum possible lifespan is achieved.

For this purpose, the following methods, described by way of example, are used today.

Heat sinks are arranged so that the heat generated by the light or radiation source is dissipated to the environment. In this case, of course, a corresponding heat sink is necessary, which in turn must be placed in the device or outside. This requires on the one hand structural effort, on the other hand it makes the device unwieldy.

The light or radiation source is operated pulsed, eg with 1 Hz or less. Thus, the light source generates less heat and the cooling performance can be reduced. However, this makes continuous measurement impossible, in particular, individual peak values can not be detected. The radiation source is placed in the fluid flow for cooling. However, this method has the disadvantage that particles which are in the fluid stream can be precipitated at the radiation source. This in turn reduces the emitted radiation power, which can be radiated into the measuring chamber. If, on the other hand, the radiation source is placed in a region with reduced fluid flow, then the cooling capacity may not be sufficient, which in turn reduces the service life of the radiation source.

Finally, a radiation source with reduced power can be used. However, this reduces the measuring and detection capability of the device.

The present invention has set itself the task, the o.g. Disadvantages of the known methods and devices also to avoid in relation to the third problem area. This object is achieved by means of measures and devices as defined in the patent claims, with advantageous embodiments and applications of the invention appearing in particular from the dependent claims.

Thus, the arrangement of the cooling device for the radiation source for measuring and analyzing devices shown here is suitable for avoiding the mentioned disadvantages of the known arrangements and for maintaining a constant, high radiation power over a long period of time. It is also characterized by a simple construction and thus cost-effective production.

A fourth problem area relates to the size or bandwidth of the electrical measuring range of measuring and analysis devices of the type described here. In the measurement of very small amounts of particles on, for example, fire alarms, rosolpartikeln, a radiation source, such as an LED, laser diode (LD), xenon lamp, etc., their radiation in a measuring range. A highly sensitive photoelectric sensor with an electrical amplifier circuit then measures the radiation haze or radiation reflection caused by particles in the medium in the measuring chamber. As a rule, the signal amplification takes place via a plurality of transistors connected in series (Darlington circuits) or operational amplifiers.

In order to detect even small amounts of very small particles, at least one, usually several of the following conditions must be fulfilled:

1. A measuring system with a very high signal-to-noise ratio (S / N ratio); 2. a radiation source with the required radiant power;

3. a large amplification of the sensor output signal in order to provide a signal processable for the evaluation circuit, e.g. for an ad.

The disadvantage of this characteristic, however, is that although very small amounts of particles can be measured with a very high resolution, the electrical measuring range is very small for this. In certain application cases, however, one not only wants to measure the smallest amounts of particles, but also an increased amount. There then fails the measuring device, because the electrical measuring range is exceeded.

EP 0733894 shows a possible solution to this problem. In this solution, a sensor reduces the drive current supplied to the light source to lower the sensitivity of the device to a lower level. The disadvantage here is that this control is complicated and not necessarily linear, because of the control of the light source up To the sensor, which receives the signal are too many components, which adversely affect their tolerances, aging, etc., a linear measurement result.

Another possibility is to change the gain of one or more amplifiers connected in series. Thus, e.g. switched from one gain value to another by means of a switch. Since in many amplifiers resistance values determine the gain, one can use e.g. Switch mechanical switch from one resistance value to another, thereby changing the gain of the circuit. This can thus be increased or reduced. The disadvantage here is that it must be switched, either manually or electronically, the latter in turn requires additional components.

Again, the present invention provides a solution; these are defined in the patent claims, with advantageous embodiments and applications of the invention appearing in particular from the dependent claims.

The circuit according to the invention, which amplifies the output signal of the sensor, has a very large amplification range without requiring manual switching and allows an automatic display of a very wide range of measured values. It is characterized by a simple structure and thus cost-effective production.

The fifth problem area in connection with analysis and measuring devices of the type mentioned is the interface for the basic setting and the commissioning of such a device, in particular a fire detector. It There is no need for a special fantasy that the incorrect setting of a fire alarm can have catastrophic consequences.

As already described, often devices are used for the detection and measurement of impurities in air or other gases, which sucks in samples via a piping system by means of a suction device, feed them to a measuring chamber and evaluate them there. The piping system is i.d.R. between 10m and 200m long and usually has several suction openings, often with an opening diameter of 2-6mm. The devices for the detection of fire aerosols are called aspirating smoke detectors (ARM or ASD for Aspirating Smoke Detector) and are widely used.

These devices must be set up on site and this adjustment or commissioning is complicated, error prone and a misalignment, as mentioned, have catastrophic consequences.

It is state of the art in the commissioning of aspirating smoke detectors, the sensitivity of the measuring chamber or its evaluation in% opacity / m set. For example, often 0.5% light haze / m is set on the device on delivery. For commissioning on site, the required setting value must be determined and the setting must be corrected. However, this itself does not say whether the device setting is a normal, high or highest sensitivity, or how fast, e.g. a fire hazard is detected.

When setting, a field technician must first determine the desired target per intake. If you want to achieve a response that is comparable to a conventional point detector, so for example, 5% light haze / m is selected. The technician must either know this value by heart or look up or ask for it. In the worst case, in the worst case, smoke only reaches a single intake opening with fire aerosols; in all other intake openings, only (pure) air still passes without fire aerosols. If the pipe system now has a certain number of suction openings, the desired target value per suction opening must be divided by the number of suction openings. The result of the division must then be set on the device. If, for example, a pipe system has 6 suction openings and the target value per suction opening is 5% light turbidity / m, the value of 0.83% light haze / m is calculated, namely 5%: 6 = 0.83%. This value must be set in the measuring chamber or its evaluation electronics. If fire aerosols now cause a light turbidity of 0.83% light turbidity / m in the measuring chamber, the device triggers an alarm.

This type of adjustment, as is the case with virtually all devices available on the market, requires an invoice which, although not very complicated, can easily lead to errors. The fatal consequences have already been mentioned above.

Again, the present invention provides a simple and practical solution by proposing an arrangement in which only the number of suction holes must be entered. This simple process is hardly error-prone and therefore leads to a largely safe start-up especially of fire detectors (aspirating smoke detectors).

Details of the invention can be taken from the claims and the following description of exemplary embodiments in conjunction with the drawings. Description of several embodiments

Hereinafter, the various aspects of the invention with reference to embodiments, which are also shown in the accompanying drawings, explained in detail. On the drawings show:

1 shows a fire alarm system in the basic structure;

FIGS. 2a-2c three embodiments for a particle separation;

FIGS. 3a-3c show further embodiments for a particle separation, wherein FIG. 3a is a plan view and FIGS. 3b and 3c show schematic views of two embodiments;

4 shows an example of a cooled radiation source;

Fig. 5 shows an example of the arrangement of shields;

Fig. 6 shows an example of a multi-range amplifier circuit;

7 shows a table of the achievable amplification factors; FIGS. 8a-8b show two embodiments of adjusting devices; and

9 is a table for calculating the basic setting of a

Fire detector.

The particle separation described below is characterized by a high throughput, a high selectivity and a cost-effective production and avoids the disadvantages of the above-mentioned, known methods.

The basic idea is to carry out a particle separation in advance in a fluid or air system in such a way that only the desired target particles reach the actual measuring chamber.

Fig. 1 shows as an example a fire alarm system. There, the particle separation is achieved by the air is taken up by a pipeline system 11 and flows into the fire alarm device 12. The piping system 11 consists of one or more pipes and each thereof has at least one, usually a plurality of suction openings 14. A pressure difference or negative pressure, which is generated by a suction device, such as a fan 13, causes the inflow of air, which thus flows from the suction via the piping to the fire detection device 12. In the latter there is a branching chamber 24. This separates the particles in the intake air and only that part with the desired target particles reaches the measuring chamber 15. This then measures the particle occurrence. The air with all particles leaves the fire alarm device 12 via the housing output 29. The device has an interface 16, which for example displays measurement data or status information, provides adjustment or data transmission options.

Fig. 1 shows, so to speak, the basic structure. FIG. 2 a shows a first example of the particle separation process according to the invention, in which the particle separation according to the invention takes place by acceleration and subsequent deceleration. At the inlet channel 20, here a pipe reaching into the actual branching chamber 24, the pipe system shown in FIG. 1 is connected. Due to the narrow tube cross-section, which has a smaller inside diameter than the connected (not shown here) pipe system, there is an acceleration of the incoming air. The inlet duct 20 terminates in the lower region of the branching chamber 24. The air flowing out of its inlet opening 25, the total flow, retains the direction, but reduces the speed because of the cross-sectional enlargement of the branching chamber in the delay region 30 and the resulting possibility of expansion. The delay of the larger particles contained in the main stream is smaller than that of the smaller particles, essentially as a result of the ratio of mass to surface of the particles. Thus, the smaller particles are deflected easier. Overall, the movement of the fluid, here the air, generated by the fan 13. The negative pressure prevailing in the branching chamber 24 is caused on the one hand via the measuring chamber outlet 31, measuring chamber 15 and measuring chamber inlet or measuring chamber branch 26a, on the other hand via the outlet channel 22, wherein the pressure ratios are set so that the slower, smaller particles in the secondary flow to the measuring chamber branch 26a, which is shown here at the other end of the branch chamber 24. However, the latter is not an unalterable condition, but the measuring chamber branch 26a can also be located closer to the delay region 27, as shown in FIG. 2c. There is also another exit angle α at the Meßkammerabzweigung, here about 90 degrees, shown, the z. B. may be an obtuse angle of about 135 degrees, ie an acute angle relative to the main stream 21st

From the measuring chamber branch 26a, the now calmed side stream 28 with the smaller target particles passes to the measuring chamber 15. This secondary stream 28 is considerably smaller than the total stream 21 in the inlet channel 20.

A particular advantage is the arrangement of the Meßkammerabzweigung 26a at a considerable distance from the delay region 30 on the outer wall of the branch chamber 24. This calms namely the flow and enters the branch channel 32a calmed, which is for the subsequent measurement in the measuring chamber 15 as advantageous proves.

The construction shown causes with great certainty that larger particles remain in the main stream 21 and prevent them from reaching the measuring chamber. For Meßkammerabzweigung 26 a and subsequently into the measuring chamber 15 reach only the smaller target particles whose presence and, where appropriate, density in the measuring chamber 15 is to be determined. The necessary for the function of the device vacuum is, as I said, generated by the fan 13. Since a certain negative pressure must prevail at the measuring chamber branch 26a in order to bring the secondary flow into the measuring chamber 15, the ratio of the flow velocities in the inlet channel 20 and in the outlet channel 22 is important since the negative pressure in the measuring chamber region is indeed generated via the measuring chamber outlet 31 , It has proved to be advantageous to select the cross section of the outlet channel 22 smaller than that of the inlet channel 20, preferably approximately half as large.

In order to give the main stream 21 as much speed as possible when entering the delay region 30, which is essential for good and reliable particle separation, as mentioned above, the inlet opening 25 of the inlet channel 20 can be designed as a nozzle, preferably with one clear cross section, which is about half the size of the clear cross section of the inlet channel 20.

Furthermore, it is advantageous to make the outlet opening 27 of the delay region 30, which forms the entrance of the outlet channel 22, so as a funnel-shaped inlet, that it opposes the main stream 23 as low as possible resistance.

It also appears to be of importance for the safety and quality of the separation of main and secondary flow that quasi a congestion occurs in the delay region 30 before the main flow 23 with the larger particles enters the outlet channel 22.

In the measuring chamber 15 are the measuring electronics and the required, eg optical components. After the secondary stream 28 has flowed through the measuring chamber 15 with the target particles, this arrives at Messkammerauslass 31, where it is merged with the main stream 23 again. Together they then go to the intake, the fan 13 and subsequently to the housing output 29th

FIG. 2b illustrates a variation of the design shown in FIG. 2a. Again, a critical feature of the invention is the delay region 30 in which the expansion of the incoming total fluid flow 21 occurs. On the one hand, the branch chamber tapers in the direction of flow of the total flow 21, at least in the delay region 30 up to the outlet opening 27. The first partial flow with the target particles from the delay region 30 thus flows at an angle y to the measuring chamber branch 26b.

Also here the measuring chamber branch 26b is designed differently than in Fig. 2a. The adjoining branch channel 32b to the measuring chamber 15 is at least approximately circular arc-shaped and has the radius r. The length transition is carried out without edges, in order to avoid air turbulence and pressure losses. Depending on the separation requirement, the angle γ and / or the distance from the delay region 30 to the measuring chamber branch 26b are also varied in the design. If only very small particles in the inflowing fluid 21 are to be the target particles, the distance from the delay region 30 to the measuring chamber branch 26b becomes greater and / or the angle γ smaller, e.g. 10 degrees, chosen.

If, for example, the separation of particles smaller than 10 μm (microns) is to be achieved, then larger particles may not get into the measuring chamber 15 and thus must remain in the main stream. This is necessary, for example, for the detection of fire aerosol particles, since these are smaller than 10 μm, depending on the type, course and time of the measurement. In order to achieve this degree of separation, the ratio between the width or the length of the delay region 30 must be 2: 1 or 1/5 of the tube diameter. Messers at the inlet opening 25 amount. The ratio of the distance from the inlet opening 25 to the measuring chamber branch 26b to the pipe diameter of the inlet channel 20 is approximately 1: 1, wherein the angle γ should be less than 20 degrees. This embodiment is shown in Fig. 2b.

FIG. 2 c shows a further embodiment, in which also larger particles of the inflowing fluid 23 belong to the target particles. There, both the delay region 30 itself is different, in particular narrower and shorter, and the distance from the delay region 30 to the measuring chamber branch 26c is smaller. To this end, alternatively or additionally, the angle γ less than 90 degrees, e.g. 70 degrees, to be chosen.

The particle separation is essentially determined by the following factors:

Shape / design of the branch chamber and the delay region 30; - Distance, broadening and subsequent tapering of the inlet opening 25 to the outlet opening 27; Distance from the inlet opening 25 to the measuring chamber branch 26;

Pressure difference Δp between the inlet opening 25 and the measuring chamber branch 26th

A significant advantage of the device described is the cost-effective production of the branching chamber, since this can have virtually any shape, both round and square or rectangular can be, which makes the production relatively simple. The Fign. 3a to 3c show further examples of the particle separation process according to the invention. Here the particle separation takes place by centrifugal forces. In this example - as in the preceding - the medium may be a liquid, but also a gas or gas mixture such as air, in short a fluid.

It is known that a particle separation can also be achieved by a rotational movement and the associated centrifugal force. In this case, the particle-containing fluid is offset by suitable flow guidance in a rotational movement, which act on the heavier and usually larger particles centrifugal forces that have a movement of these particles radially outward. The larger particles are thus pushed to the edge and in the middle of the fluid are the smaller particles. So-called cyclones use this process for separating solid and liquid particles.

In the present case, however, no deposition of the particles takes place. The larger particles remain in the main flow of the fluid and later escape from the device again. There is a separation and only the fluid with the smaller particles gets into the measuring chamber; later this fluid gets back into the main stream and leaves the unit.

The function of such a device will now be described in connection with FIGS. 3a to 3c, of which Fig. 3a is a plan view, the other two figures represent schematic sectional views.

A container 54, which here represents the branching chamber 50, has an inlet opening 53, a measuring chamber branch 55 and a downwardly narrowing outlet opening with an adjoining outlet channel 62; the latter are shown in FIGS. 3b and 3c can be seen. In the container 54, the fluid 52 flows tangentially through the inlet opening 53, which may be formed, for example, as a slot inlet. The arrangement of the inlet channel 51 and the container forces the fluid now in a circular path 56, ie in a rotary flow. In general, the heavier particles, which are usually also the larger ones, will move to the outer wall of the container as a result of the centrifugal forces acting on them.

In the middle of the container are thus only the smaller, lighter particles. Here, the Messkammerabzweigung is arranged, which consists of a tube 68 with an opening 64. Due to the existing pressure difference, a small amount of the fluid 65 now flows through the opening 64 of the measuring chamber branch and subsequently arrives in a measuring chamber 15. There, the quantity or number of smaller or lighter target particles is measured. Heavier particles do not get into the measuring chamber. The heavier particle mainstream fluid 63 flows downwardly, accelerated by the negative pressure generated by the fan 13. Bottom of the container 50 has a narrowing outlet channel 62, in which the flow rate of the fluid increases. At this point, the measurement chamber outlet is additionally arranged laterally, in which the required negative pressure is produced by the high flow velocity of the exiting main stream 63.

The container 60 may on the one hand be cylindrical, as shown in Fig. 3b. On the other hand, a conical container, as shown in Fig. 3c can be used. Of course, mixed forms are possible. If the container has the conical shape shown in FIG. 3c with the angle δ, then the radius 71 decreases in the direction of the flow 63, which results in an increase in the flow velocity of the fluid with the particles. Advantageously, thereby increase the centrifugal forces. When entering a so-called spiral inlet is possible, alternatively, a so-called helical inlet is used when the fluid flows perpendicular to the outlet opening.

In this case the particle separation is essentially determined by the following factors:

Diameter and height of the container

Pipe length of the measuring chamber branch - opening cross section or diameter of the pipe of the measuring chamber branch

Pressure difference Δp between the opening of the tube of the measuring chamber branch and the main fluid flow Flow velocity of the fluid in the container

The above-mentioned third problem area in the measurement and analysis methods and devices discussed here relates to the light or radiation source arranged in or on the measuring chamber. On the one hand, the necessary cooling is to be considered, on the other hand, the pollution occurring during operation by deposition of particles. Both influence the power of the radiation source and thus the accuracy of the measurement or analysis.

The Fign. 4 and 5 show by way of example a solution according to the invention which avoids the disadvantages mentioned above.

4 shows three views of a light source arranged on a plate, eg a printed circuit board 80, here an LED 81. This printed circuit board with the LED is shown in FIG. 4 in the front view 80a, side view 80b and in the rear view 80c. The reference numbers are repeated in FIG. 5. In this case, the underside of the circuit board 80 acts as a heat sink and is therefore coated with a temperature-conductive material 82. A temperature-conductive via 83 allows the heat flow from the light source to the temperature-conductive material 82. Thus, the heat of the light source reaches the back of the circuit board and can be from there or forwarded.

In order to optimize the heat dissipation, the backside of the printed circuit board 80 - that with the temperature-conductive material 82 - is placed in the main stream 86 of the medium or fluid. M.a.W. the useless main flow of the fluid serves to cool the light or radiation source required for the particle measurement in the secondary flow. Thus, the heat dissipation and the cooling of the light source is lent considerably improved without further effort.

A solution according to the invention is shown in FIG. There, the radiation source 81 emits its radiation through an opening 84 into the measuring chamber 15. By e.g. Radiation haze or reflections, caused by presence of particles, their existence in the medium or fluid can be detected and measured. This is done by means of a sensor 86a for measuring radiation reflections and / or a sensor 85b for measuring the radiation haze, i. for transmission measurement. Both measurements can also be made.

In order to ensure a lasting and sufficient cooling, a fluid flow 86 must be present. Should this fail - because, for example, the suction device 13 is defective - this would adversely affect the life of the radiation source. Thus, the flow or the intake device should be monitored, which can be done by means of a monitoring circuit 87. This gives the driver current for the Light source free as long as the suction device is running and generates a corresponding fluid flow,. Should the aspirator fail or malfunction, the monitoring circuit disables or reduces the drive current. Overheating of the radiation source 81 is thus prevented. The monitoring circuit can display this state on a local display or transmit this information to an external display.

The above-mentioned problem of particle deposition, which on the one hand already substantially reduced by the described particle separation, if not avoided, can still be reduced by further measures.

In FIG. 5, a series of radiation-transmitting or light-transmitting shields 88, 88a and 88b are arranged. Shield 88 is located directly in front of the radiation source 81; the shield 88a in front of the sensor 85a for the reflection measurement and the shield 88b in front of the sensor 85b for the transmission measurement. The shields are fixed by the brackets 90, 90a and 90b.

The shields together with the brackets should meet the following conditions:

1. The shields extend to the entrance or the beginning of the measuring chamber, where the fluid flows. They must have a length that gives rise to possible turbulence at the beginning of the shield and not in the measuring range. This turbulence is caused by the shields themselves and the necessary brackets, which inevitably arise bumps, joints, openings, etc., which cause by swirling the deposition of particles in these areas. However, this is outside the measuring range and therefore has no influence on the measurement. 2. The measuring components, such as the radiation sources, sensors, lenses, etc., must be covered. In these areas, the shields must not be interrupted.

3. The shields extend downstream past the area used for the measurement. Any unevenness, joints,

Although openings, etc., in turn lead to turbulence and thus to the deposition of particles. However, this is again outside the measuring range and therefore has no influence on the measurement.

Although the shielding 89 in front of the radiation source 81 reduces the amount of radiation which is emitted into the measuring range, the shield in front of the sensor reduces the amount of radiation which reaches the sensor, but this effect remains constant over the service life, since no particles are deposited here. The device can now be calibrated accordingly in the production and then has constant measuring sensitivity during the entire operating time. A recalibration is unnecessary.

The problem mentioned at the outset of the too small electrical measuring range or measuring band solves the invention by means of a correspondingly modified, relatively simple amplifier circuit with an extended dynamic range. Measuring band range, which is described below.

Fig. 6 shows this amplifier circuit. The IC1 receives the very small input signal 100 from one sensor, with a few mV or mA or less. This can be, for example, the output signal of a photodiode. This very small signal must now be amplified accordingly in order to be able to process it further. It is picked up at the output 103, where it is usually amplified to several volts. For this purpose, a plurality of operational amplifiers connected in series are usually used. For the operational amplifiers, the amplification is determined by the ratio of coupling resistance to the input resistance. Thus, the gain of the IC1 is determined by R2 / R1, the gain of the IC2 by R4 / R3 and that of the IC3 by R6 / R5. This means that the very small input signal 100 is amplified to the desired value via these three operational amplifiers and is then present at the output 103. If the input signal continues to rise, IC3 saturates at a certain input value, which means that the signal at the output 103 can no longer increase. From here, the measured values can no longer be determined.

In the circuit of Fig. 6, the signal is split after the first amplifier stage IC 1. The output signal of the IC 1 is fed both to the IC2 as input signal 101 (and later through the IC3 to the output 103) and to the IC4 as input signal 102. In the case of the IC, the gain is determined by the ratio R8 / R7, but chosen that the IC4 has a lower gain than IC2 and IC3 together. Thus, with higher input signals 100, the IC3 saturates, but not the IC4. Consequently, a measurement signal which is related to the input signal 100 is then still present at the output 104 of the IC4.

Assuming that all the operational amplifiers shown in FIG. 6 have the same gain factor of 10, the input signal 100 is amplified by the factor 10E3 to the output 103 and by the factor 10E2 to the output 104. This results in the table shown in Fig. 7. The column T100 represents the value of the input signal 100, the column T103 the value of the output 103 and the column T104 the value of the output 104. All values are in mV and it is assumed that the operational amplifier is from 10'00OmV, ie from 10V, in saturation. Up to an input value of 10mV, the output 103 has a higher resolution than the output 104. However, due to the saturation, higher input values can no longer be represented at the output 103. From here on then the signal of the Output 104 accessed, which can still represent input signals up to 10OmV.

The signal may e.g. be brought from the output 103 by means of a converter 105 to a first bar graph display 107 for display. This indicates the low particle values. The signal of the output 104 is, e.g. also displayed via a converter 106 on a second bar graph display 108. This then indicates the larger particle concentrations.

The two displays 107 and 108 can be provided with the corresponding voltage specifications in mV from 1 to 10 or from 10 to 100. These can represent any other values or even omitted. Similarly, the two outputs 103 and 104 can be fed via an analog-to-digital converter in a microprocessor, where the output signals are further processed. A representation may then be made on a local display on the device and / or transmitted over a data link to display the signal on an external display or process it, e.g. in a computer system.

As a final task in analysis and measuring devices of the type mentioned above, the interface for the basic setting and commissioning of such a device, in particular a fire detector has been described.

A novel setting interface according to the invention prevents errors and reduces the time required for commissioning a fire detector and similar devices. As described above in connection with FIG. 1, devices 12 are used for the detection and measurement of impurities in gases and gas mixtures, in particular air, which are conveyed via a pipeline system 11 by means of a suction device 13 Aspirates gas samples and this feeds a measuring chamber 15, where they are evaluated. The piping system is usually between 10 and 200m long and usually has several suction openings 14.

The inventive method and the corresponding arrangement is so simple that incorrect settings, which are of course particularly critical fire detectors, can be virtually eliminated.

Details are shown in FIGS. 8a, 8b and 9, which will be explained below.

On the display 120 shown in FIG. 8a, in the method according to the invention, the number of suction holes is set, which is e.g. by means of a first key 121, which increases the number of suction holes by one each upon pressing, and optionally a second key 123, which reduces the number of suction holes by one each when pressed, and an acknowledgment or confirmation key 122 which determines the input procedure completed. This display does not necessarily have to be on the device. It can be designed both as a portable device with a connector, as well as a software solution that runs on a PC and is transmitted via data interface to the device.

In Fig. 8b, another setting option is shown. A so-called DIP or DIL switch 124 arranged on a printed circuit board has e.g. 12 small switches. If e.g. Switch # 10 is ON / ON position and all others are OFF, then you set 10 intake ports.

After the number of suction holes has been adjusted, the triggering and alarm threshold is calculated by default for a target value of eg 5% light turbidity / m for each suction opening. This is the in Fig. 9 stored table. The first line 130 contains the target value per intake opening. The number of suction holes is listed in column 131. The result is calculated by dividing the target value per intake port by the number of intake ports. This result is then displayed in column 132. For example, with eight suction openings and the standard target value per suction opening of 5% light turbidity / m, the measuring chamber must trigger an alarm at a light turbidity value of 0.63.

In addition to the unit of% haze per meter, dB / m is also used. Of course, the new setting interface mentioned here works with both units.

The table in Fig. 9 shows two more settings. With a target value of 8% haze / m for each aspiration opening, the triggering of an alarm would be delayed, whereas the triggering would occur earlier at a target level of 2% haze / m for each aspiration opening. This is shown in columns 133 and 134. Of course, further and other gradation values are possible.

The above detailed descriptions allow those skilled in the art to make other embodiments of the invention, wherein the particle measurement and determination is significantly improved already if only a part of the o.g. Elements of the invention is used.

Claims

1. Arrangement for the analysis of particles distributed in a fluid with different properties, comprising - a branching chamber (24, 50), in which the inflowing fluid (21) is divided into two partial streams with different particle properties, of which the first partial stream (28) as Secondary stream contains the lighter target particles to be analyzed and the second partial stream (23) contains the heavier residual particles as the main stream.

- And one of the branch chamber (24, 50) downstream of the measuring chamber (15) with a measuring device (81, 85a, 85b) into which the first partial stream (28) passed with the target particles and these are analyzed by the measuring device, characterized in that a part of the branching chamber (24) is designed as a delay region (30), in which a separation of the lighter target particles by delaying the heavier residual particles and thus a separation of the two partial streams (23, 28) occurs by a cross-sectional enlargement,

- That on an outer wall of the branching chamber (24) is provided with a vacuum applied measuring chamber branch (26) through which the first partial stream (28) discharged with the target particles and the measuring chamber (15) is supplied.

2. Arrangement according to claim 1, characterized

- That the branch chamber (24) consists of an outer hollow body having a first clear cross-section and an approximately centrally in this outer hollow body extending in, shorter inner hollow body as inlet channel (20), in particular a straight tube, with a second, lower clear cross section through which the fluid (21) flows, wherein the delay region (30) through the space between the end (25) of the inner hollow body and the end of the outer hollow body is formed.

3. Arrangement according to claim 1 or 2, characterized

- That the branch chamber (24) in the flow direction preferably approximately centrally has a narrowed compared to the branch chamber outlet channel (22) through which the second partial stream (23, 63) of the fluid is discharged.

4. Arrangement according to claim 3, characterized

- That the clear cross section of the outlet channel (22) is about half as large as that of the inlet channel (20).

5. Arrangement according to at least one of the preceding claims, characterized

- That the inlet channel (20) at its end directed into the delay region (30) has a nozzle whose light cross section is about half the size of the clear cross section of the inlet channel (20).

6. Arrangement according to at least one of the preceding claims, characterized in that

- That the measuring chamber branch (26) at a predetermined distance from the delay region (30) opposite to the direction of the inflowing fluid (21) is arranged and the angle a between branch (26 a) and wall of the branch chamber (24) approximately 90 ° + / - 20 ".

7. Arrangement according to at least one of claims 1 to 5, characterized in that - the measuring chamber branch (26c), in particular close to the retarding region (30), is arranged such that it makes an acute angle with the direction of the inflowing fluid (21) γ, ie forms an angle of less than 90 degrees.

8. Arrangement according to at least one of the preceding claims, characterized in that

- That the outer hollow body of the branch chamber (24) at its lying in the delay region (30) end has a smaller clear cross section than at its opposite end.

9. Arrangement according to at least one of the preceding claims, characterized

- That in the outlet channel (22) a Meßkammerauslass (31) for the out of the measuring chamber (15) effluent first part stream (28) is arranged, whereby in the measuring chamber (15), a negative pressure is generated.

10. Arrangement according to claim 1, characterized

- That the branch chamber (50) is designed as a cyclone or hydrocyclone, which has approximately centrally a measuring chamber branch (68), by means of which the first partial flow (65) of the fluid is discharged with lighter particles.

11. Arrangement according to at least one of the preceding claims, characterized

- That at least a portion of the measuring device (81) is arranged so that it from the second partial stream (86), preferably facing away from the measuring chamber (15)

Side, can be flown around and cooled.

12. Arrangement according to claim 11, characterized

in that in the measuring chamber (15) a radiation source (81) and radiation-sensitive sensors (85a, 85b) for determining the transmission or the

Reflection of the first partial flow (28) of the fluid are provided and

- That the radiation source (81) at its located outside the measuring chamber (15) located rear side (83) is cooled by the second partial stream.

13. Arrangement according to claim 1, characterized

in that at least one radiation-transmissive shield (88, 88a, 88b) is arranged in the measuring chamber, preferably a first shield (88) in front of the radiation source (81) and a second shield (88a, 88b) in front of one of the sensors ( 85a, 85b), wherein the shield extends in particular from the entrance of the measuring chamber to beyond the radiation source or the sensor.

14. Arrangement according to at least one of the preceding claims, characterized in that

- That the various components are arranged in a common, except for at least one inlet opening and an outlet opening closed housing and

- That in or on this housing, a suction device (13), in particular a fan, is arranged to generate a negative pressure.

15. Arrangement according to at least one of the preceding claims, characterized in that

- That it is designed as a fire alarm device (12).

Amplifier circuit for use with an arrangement for analysis according to at least one of claims 1 to 13, characterized in that - a plurality of operational amplifiers (IC1 ... IC4) are provided, of which a first (IC1) receives the input signal (100) to be amplified and gives off an amplified output,

- That this output signal is supplied to a first branch of two or more operational amplifiers (IC2, IC3), wherein the last operational amplifier (IC3) from a certain level of the input signal comes to saturation, and

- That the output signal is simultaneously supplied in parallel to a second branch of one or more operational amplifiers (IC4), wherein the total gain of the second branch is selected to be less than the total gain of the first branch, so that the operational amplifier (IC4) of the second branch saturation not or later than the last operational amplifier (IC3) of the first branch.

17. A method for basic setting or commissioning of an arrangement for the analysis according to at least one of claims 1 to 13 with a plurality of suction openings (14), in particular a fire alarm device (12) according to claim 11, characterized in that the number of suction openings (14, 131) is adjusted by means of a first input device (121, 124),

in that a target value (130) for the desired light haze is selected from a stored value table (FIG. 9) by means of a second input device, and

- That from this automatically the alarm threshold value of the light turbidity is determined, in which the measuring device (81, 85a, 85b) responds.