CN110887769A

CN110887769A - Particle sensor device

Info

Publication number: CN110887769A
Application number: CN201910841496.8A
Authority: CN
Inventors: F·塔肯
Original assignee: Paragon GmbH and Co KGaA
Current assignee: Paragon GmbH and Co KGaA
Priority date: 2018-09-07
Filing date: 2019-09-06
Publication date: 2020-03-17
Also published as: DE102018007086A1

Abstract

A particle sensor device (1) has: an optical unit (5) by means of which the particle load of the measurement gas volume can be detected (5); a measurement chamber (2), in which measurement chamber (2) an optical unit (5) is arranged and into which measurement gas can be introduced through an inlet channel (3); and a main gas duct (6), through which the measurement gas can be led out of the measurement chamber (2) by means of a fan (7). In order to provide the best possible flow conditions for the measurement process by means of the optical unit (5) within the measurement chamber (2), it is proposed that the particle sensor device (1) has a secondary air duct (9), which secondary air duct (9) is connected to the position of the primary air duct (6) on the primary air duct (6) arranged downstream of the measurement chamber (2) and having a higher pressure than the pressure in the measurement chamber (2), and to the measurement chamber (2) or to the region of the inlet duct (3) arranged upstream of the measurement chamber (2).

Description

Particle sensor device

Technical Field

The present invention relates to a particle sensor device, comprising: an optical unit, by means of which the particle load of the measurement gas volume can be detected; a measurement chamber in which an optical unit of the particle sensor device is arranged and into which a measurement gas can be introduced through an inlet channel; and a main air passage through which the measurement gas can be led out of the measurement chamber by means of a fan.

Background

In such particle sensor devices known from the prior art, a measurement gas (here usually air) is introduced into the measurement chamber through an inlet channel and is guided from the measurement chamber to an outlet of the main gas duct.

In this process, the measurement gas or air enters the measurement chamber very rapidly from an inlet channel with a relatively small inlet nozzle. Since the measuring chamber takes up a relatively large volume due to the space required by the optical unit, the measuring gas or air moves slowly there. In addition to the quasi-static vacuum generated by the fan, a dynamic vacuum is thereby additionally formed by the inertia of the measuring gas or air mass flowing in rapidly from the inlet nozzle of the inlet channel, due to the friction between the rapid and slow measuring gas or air flows.

As soon as the static and dynamic underpressure in the measuring chamber is greater than the static pressure in the main air duct arranged downstream of the measuring chamber, the measuring gas or air flows back into the measuring chamber in the opposite direction to the original flow direction. On the one hand, this backflow takes place continuously in the laminar flow of the measurement gas or air, which becomes turbulent eddies in the measurement chamber. On the other hand, the reflux is intermittent and chaotic. In both cases, there is an undefined measuring gas or air flow in the measuring chamber, the nature and shape of which depends to a large extent on the measuring gas or air velocity and the measuring gas or air density, on which the temperature, the particle load, the air humidity, etc. contribute.

Disclosure of Invention

Starting from the above-described prior art, the object of the present invention is to further develop a particle sensor device of the type mentioned in the introduction in such a way that a measurement in the measurement chamber of the particle sensor device by means of the optical unit allows a more reliable measurement value with respect to the particle load of the measurement gas located in the measurement chamber.

According to the invention, this object is achieved by: the particle sensor device has a secondary air duct connected to a primary air duct position on the primary air duct arranged downstream of the measurement chamber and having a higher pressure than the pressure in the measurement chamber, and to the measurement chamber or an inlet channel region arranged upstream of the measurement chamber. Due to the measurement gas entering the measurement chamber through the secondary gas duct, backflow of measurement gas from the region of the primary gas duct downstream of the measurement chamber is reduced, which backflow can cause turbulence in the measurement chamber, etc.

The transport of the measurement gas from the secondary air duct into the measurement chamber can advantageously be stabilized or increased if the primary air duct is configured such that the dynamic measurement gas pressure in the primary air duct in the inlet region on the primary air duct side of the secondary air duct increases.

According to a further advantageous embodiment, the flow conditions when the measurement gas enters the measurement chamber from the secondary gas duct can be regularly ordered if the primary gas duct and/or the measurement chamber are configured such that the dynamic measurement gas pressure in the measurement chamber side outlet region of the secondary gas duct is reduced.

In order to further reduce any backflow of the measurement gas flowing into the measurement chamber from the region of the main gas duct arranged downstream of the measurement chamber, it is advantageous if the main gas duct of the particle sensor device is configured with a taper between the inlet of the secondary gas duct and its outlet, by means of which a backflow of the measurement gas in the main gas duct towards the measurement chamber can be reduced or prevented.

Drawings

The invention will be further explained below according to embodiments with reference to the drawings.

The figures show:

fig. 1 shows a first embodiment of a particle sensor device according to the invention;

fig. 2 shows a first embodiment of the particle sensor device according to the invention shown in fig. 1, wherein for the sake of explanation and illustration a flow of measurement gas flowing in the particle sensor device is shown;

fig. 3 shows a second embodiment of a particle sensor device according to the invention; and

fig. 4 shows an embodiment of the particle sensor device according to the invention shown in fig. 3, in which the flow of the measurement gas flowing in the particle sensor device is shown.

Detailed Description

The particle sensor device 1 shown in fig. 1 according to the first embodiment has a measurement chamber 2, into which measurement chamber 2 a flow of measurement gas 4 shown in fig. 2 can be introduced via an inlet channel 3.

An optical unit 5, which is illustrated in fig. 2 by an arrow drawn in the measurement chamber 2, is provided in the measurement chamber 2, by means of which optical unit 5 the particle load of the measurement gas volume of the measurement gas flow 4 introduced into the measurement chamber 2 can be detected.

The main air duct 6 of the particle sensor device 1 is connected to the measurement chamber 2 of the particle sensor device 1. The measurement gas can be led out of the measurement chamber 2 by passing through the main gas duct 6. For this purpose, a fan 7 is provided at the end section of the main gas duct 6 remote from the measuring chamber 2, by means of which fan 7 the measuring gas can be conveyed out of the measuring chamber 2.

Downstream of the measuring chamber 2 and upstream of the fan 7, the primary air duct 6 has an area where a secondary air duct 9 is connected to the primary air duct 6 via a primary air duct side inlet 8. The measurement gas flows from the primary airway 6 through the primary airway side inlet 8 into the secondary airway 9. As can be seen from the measuring gas flow diagram in fig. 2, the flow direction of the measuring gas is almost opposite in the secondary gas duct 9 than in the primary gas duct 6.

The measurement gas flowing into the secondary gas duct 9 via the primary gas duct side inlet 8 flows back via the secondary gas duct 9 into the measurement chamber 2, wherein a measurement chamber side outlet 10 of the secondary gas duct 9 is provided at a measurement chamber side end region of the secondary gas duct 9. The measurement gas flows from the secondary gas duct 9 through this measurement chamber side outlet 10 of the secondary gas duct 9 into the measurement chamber 2.

In the region of the main gas duct 6 of the particle sensor device 1 in which the main gas duct side inlet 8 of the secondary gas duct 9 is provided, the main gas duct 6 is formed such that a measurement gas turbulence is formed. As a result, a dynamic overpressure is generated in the region of the wall of the main air duct 6, which counteracts the quasi-static underpressure generated by the fan 7. This region of the main gas duct 6 is connected to the measurement chamber 2 via a main gas duct side inlet 8 (through which the measurement gas enters the secondary gas duct 9 via the main gas duct side inlet 8) and a secondary gas duct 9, the measurement gas entering the measurement chamber 2 via a measurement chamber side outlet 10. In this region, the primary gas duct 6 is configured such that the dynamic measurement gas pressure at the measurement chamber side outlet 10 of the secondary gas duct 9 is reduced.

With the above-described embodiment of the particle sensor device 1, the flow conditions of the measurement gas can be obtained in the measurement chamber 2, wherein the particle load or burden of the measurement gas can be reliably detected with the aid of the optical unit 5 of the particle sensor device 1.

The embodiment of the particle sensor device according to the invention described below with reference to fig. 3 and 4 differs from the above-described embodiment of the particle sensor device in that in the main gas duct 6 of the particle sensor device 1 a cone 11 is constructed in a region arranged downstream of the measurement chamber 2, close to the measurement chamber 2. As can be seen from the schematic illustration of the measuring gas flow in fig. 4, this tapering 11 of the main gas duct 6 is adapted to keeping the measuring gas vortex flow outside the measuring chamber 2, which can also always be generated between the measuring chamber 2 and the fan-side end region of the main gas duct 6. Accordingly, it is possible to compensate for the dynamic underpressure in the measuring chamber 2 without measuring gas backflushing being produced by such turbulences. Accordingly, the variants of the particle sensor device 1 according to the invention shown in fig. 3 and 4 produce a relatively straight and constant flow of the measurement gas within the measurement chamber 2, whereby a high-quality measurement result for the particle load or the loading of the measurement gas can be detected by means of the optical unit 5 of the particle sensor device 1.

In order to ensure that backflow of measurement gas in the main gas duct 6 is reduced as much as possible, the above-described conical portion 11 of the main gas duct 6, which is arranged in the main gas duct 6 between the main gas duct side inlet 8 and the measurement chamber side outlet 10 of the secondary gas duct 9, is formed such that the flow of measurement gas is less obstructed in the direction provided for the main gas duct 6 than in the opposite direction.

In the particle sensor device 1 described above, the flow of measurement gas in the gas channel is stable without dilution with additional gas flow or without the need for another measurement gas inlet. The sensor of the optical unit 5 of the particle sensor device 1 works very accurately, especially when a laminar flow of gas needs to be measured. Furthermore, measurements can be carried out on the measurement gas flowing through the secondary gas duct 9, wherein a relatively low measurement gas velocity is required.

Claims

1. A particle sensor device, said particle sensor device having: an optical unit (5) by means of which the particle load of the measurement gas volume can be detected (5); a measurement chamber (2) in which the optical unit (5) of the particle sensor device (1) is arranged and into which measurement gas can be introduced (2) through an inlet channel (3); and a primary air duct (6), through which the measurement gas can be led out of the measurement chamber (2) by means of a fan (7), characterized in that the particle sensor device (1) has a secondary air duct (9), which secondary air duct (9) is connected to the position of the primary air duct (6) on the primary air duct (6) arranged downstream of the measurement chamber (2) and having a higher pressure than the pressure in the measurement chamber (2), and to the measurement chamber (2) or to the region of the inlet channel (3) arranged upstream of the measurement chamber (2).

2. A particle sensor arrangement according to claim 1, characterized in that the primary airway (6) of the particle sensor arrangement is configured such that the dynamic measurement gas pressure in the primary airway (6) in the region of the primary airway side inlet (8) of the secondary airway (9) increases.

3. Particle sensor device according to claim 1 or 2, characterized in that the main gas duct (6) and/or the measurement chamber (2) of the particle sensor device are configured such that the dynamic measurement gas pressure in the region of the measurement chamber side outlet (10) of the secondary gas duct (9) is reduced.

4. Particle sensor arrangement according to one of claims 1 to 3, characterised in that the primary gas duct (6) of the particle sensor arrangement is constructed with a taper (11) between the inlet of the secondary gas duct (9) and the outlet (10) of the secondary gas duct (9), by means of which taper (11) backflow of measurement gas in the primary gas duct (6) towards the measurement chamber (2) can be reduced or prevented.