DE102020121987A1 - air purification unit - Google Patents

Abstract

An air cleaning unit with at least one electrostatic filter module (2) through which the air to be cleaned can flow, which has at least one first electrode (22) and at least one second electrode (24), between which the air to be cleaned flows and between which a power supply module ( 7) an electrical field can be generated using the electrical high voltage provided, with the electrostatic precipitator module (2) having a mechanical filter module (3) with at least one mechanical filter element (30) in the direction of flow (V) of the air to be cleaned, which is preferably used as a particle or suspended matter filter, for example designed as a HEPA filter, is characterized in that at least a third electrode (26) is provided in the mechanical filter element (30) or in the mechanical filter module (3) behind the mechanical filter element (30), with between the at least one second electrode (24) and the at least one third electr or (26) an electrical field can be generated by applying an electrical voltage.

Description

TECHNICAL AREA

The present invention relates to an air cleaning unit according to the preamble of patent claim 1. In particular, the invention relates to such an air cleaning unit for use in vehicles and very particularly for use in aircraft.

BACKGROUND OF THE INVENTION

There are a large number of air purification devices of different designs. Simple filter systems work with so-called HEPA filters to effectively filter out particles with sizes up to approx. 0.3-0.1 µm. There are also electrical filter devices, so-called air ionizers, which produce ions that attach themselves to the smallest particles or destroy particles and odors by generating micro-oxidation in the immediate vicinity of the ionization processes. Here, so-called ionization tubes are often used or corona discharges are generated on special electrodes. In the designs that have been customary up to now, the ionization is generated by thin wires stretched in the air flow. Plate arrangements or tube systems are sometimes also used. However, the plate ionizers in particular are designed for a size of several meters with a plate length of a few centimeters. As a result, plate ionizers cannot currently be installed in existing air conditioning systems, particularly in commercial aircraft, since the design and the relative dimensions of plate size and plate spacing do not do justice to the cramped structural conditions in a vehicle, particularly in an aircraft. In addition, very high electrical voltages of 20 kV to 70 kV must be used. Ionizers with wires cannot be used either, as due to the nature of the system, they only generate effective ionization in the immediate vicinity of the wire due to the narrowing of the field lines that occurs there and therefore only work effectively at low air speeds.

STATE OF THE ART

From the U.S. 4,056,372 A electrostatic filters are known which also generate ions which attach to impurities and are then deposited and collected at a cathode. There are numerous further developments in this regard, in which the cathodes are surrounded with porous materials in order to prevent the adhering dirt particles from falling off later (US 2016/0074877 A1). A combination of these advancements shows and describes the U.S. 5,330,559 A , according to which the air is first ionized (e.g. with ionization tubes) and the particles are then collected in filters equipped with a cathode in the form of metal meshes.

PRESENTATION OF THE INVENTION

The object of the present invention is therefore to improve a generic air cleaning unit so that it can be integrated into existing air conditioning systems with a compact design and filters out particles down to particle sizes of less than 0.1 μm, in particular for effective use against viruses.

This object is achieved by an air cleaning unit having the features of patent claim 1.

An air cleaning unit with at least one electrostatic filter module through which the air to be cleaned can flow, which has at least one first electrode and at least one second electrode, between which the air to be cleaned flows and between which an electrical field can be generated by applying an electrical high voltage provided by a power supply module, wherein A mechanical filter module with at least one mechanical filter element, which is preferably designed as a HEPA filter, is arranged downstream of the electric filter module in the direction of flow of the air to be cleaned, is characterized in that in the mechanical filter element or in the mechanical filter module behind the mechanical filter element, at least a third Electrode is provided, wherein an electric field can be generated between the at least one second electrode and the at least one third electrode by applying an electrical voltage.

ADVANTAGES

The electrostatic filter module of the air cleaning unit according to the invention forms a two-stage electrostatic filter, the first stage of which has the at least one first electrode and the at least one second electrode and forms an ionizer, and the second stage of which is formed by the at least one second electrode and the at least one third electrode. A mechanical filter, preferably a particle or suspended matter filter, such as a HEPA filter, is at least partially integrated in the second electrostatic filter stage.

Within the second electrostatic precipitator stage, a second electric field is built up between the at least one second electrode and the at least one third electrode, which causes that the previously charged particles are drawn from the ionizer towards the mechanical filter and are collected there in the filter material. The invention implements an efficient ionizer that can be operated at lower voltages in order to emit less electromagnetic interference even in EMC-sensitive environments, especially in commercial aircraft.

Further preferred and advantageous design features of the air cleaning unit according to the invention are the subject matter of dependent claims 2 to 10.

The at least one first electrode and the at least one second electrode are preferably designed as plate electrodes.

It is advantageous if the at least one first electrode designed as a plate electrode is shorter in the flow direction of the air to be cleaned than the at least one second electrode also designed as a plate electrode, with the at least one second electrode extending in the downstream direction and/or in the upstream direction over the plate which protrudes at least one first electrode.

The at least one first electrode preferably has at least one electrically conductive needle extension () located essentially in the plane of the plate, which extends in the downstream direction and/or in the upstream direction beyond the plate edge of the plate electrode.

According to an advantageous embodiment of the invention, which can be combined with other embodiments, the at least one third electrode is connected to the electrical ground and both the at least one first electrode and the at least one second electrode have an electrically positive voltage measured against ground , wherein the positive voltage at the at least one first electrode is higher than the positive voltage at the at least one second electrode.

According to a further advantageous embodiment of the invention, which can also be combined with other embodiments, the at least one third electrode is tubular and is arranged in a tubular air outlet channel of the ring-cylindrical mechanical filter element.

According to yet another advantageous configuration of the invention, which can be combined with other configurations, during operation there is a controllable DC voltage between the at least one first electrode and the at least one second electrode, and between the at least one second electrode and the at least one third electrode operate at a constant DC voltage. The voltage level in the first electrostatic precipitator stage is thus designed to be adjustable and is dynamically regulated to a maximum voltage value by an electronic controller, taking into account measured variables such as anion quantity, ozone content and flashover detection.

It is advantageous in all embodiments of the invention if at least one sensor for monitoring the ozone content of the air is provided downstream of the arrangement of the at least one first electrode and the at least one second electrode in the direction of flow of the air to be cleaned.

It is also advantageous if at least one sensor for monitoring the amount of anions is additionally or alternatively provided behind the arrangement of the at least one first electrode and the at least one second electrode in the direction of flow of the air to be cleaned.

Finally, in all of the embodiments of the invention, it is advantageous if the magnitude of the electrical voltage that is present between the at least one first electrode and the at least one second electrode is determined dynamically by regulation.

The invention is also directed to an air cleaning system having an air cleaning unit according to the invention, in particular a vehicle interior air cleaning system, and to a ventilation and air conditioning system having such an air cleaning system, in particular for a vehicle or in a vehicle.

The invention is also aimed at a vehicle, in particular an aircraft, with at least one such air cleaning unit according to the invention.

Preferred exemplary embodiments of the invention with additional design details and further advantages are described and explained in more detail below with reference to the attached drawings.

character list

• 1 eine perspektivische Explosionsansicht einer erfindungsgemäßen Luftreinigungseinheit;
• 2 eine perspektivische Schnittansicht der ersten Elektrofilterstufe;
• 3 eine perspektivische Seitenansicht und
• 4 eine perspektivische Detailansicht der ersten und zweiten Elektroden der ersten Elektrofilterstufe.

It shows:

• 1 an exploded perspective view of an air cleaning unit according to the invention;
• 2 a perspective sectional view of the first electrostatic filter stage;
• 3 a perspective side view and
• 4 a perspective detailed view of the first and second electrodes of the first electrostatic precipitator stage.

ILLUSTRATION OF PREFERRED EMBODIMENTS

1 shows an air cleaning unit 1 according to the invention with an upper housing 10 and a lower housing 12. The lower housing 12 has an air inlet 11 on its underside for the air to be cleaned, which is contaminated with pollutants and harmful particles upper housing 10 and the filters contained therein flows.

An ionizer 20 of an electrostatic filter module 2 is arranged in the lower housing 12 and forms a first electrostatic filter stage 21 with first electrodes 22 designed as plate electrodes and with second electrodes 24 designed as plate electrodes ( 2 ).

In the upper housing 10 there is a mechanical filter module 3 with a mechanical filter element 30 designed as a particulate filter 31, for example as a HEPA filter. The mechanical filter module 3 is designed as a ring-cylindrical filter cartridge with a radially outer inlet surface 32 for the air to be cleaned and an air outlet duct 33 designed as an inner exhaust air duct, the peripheral surface of which forms an outlet surface 34 for the cleaned air. The cleaned air flows out again through a side opening (not shown) in the upper housing 10, as is symbolized by the arrow V'.

In the interior of the exhaust air duct forming the air outlet duct 33 there is a ring-cylindrical third electrode 26 whose electrically conductive cylinder wall 27 forming the electrode surface is perforated or consists of a mesh or grid. The third electrode 26, together with the second electrodes 24 of the ionizer 20, forms a second electrostatic precipitator stage 23.

In the upper housing 10 are sensors 4, 5 for monitoring the ionization power, for example a sensor 4 for monitoring the amount of anions and a sensor 5 for monitoring the ozone content of the air behind the ionizer.

In 2 the structure of the ionizer 20 is shown in a vertical section. The first electrodes 22 and the second electrodes 24 are arranged alternately parallel to one another and at a lateral distance from one another, a passage 25 for air to be cleaned being formed in each case between adjacent electrodes.

A row of UV light sources 6 (preferably UVC light sources) is arranged in the flow direction V behind the ionizer 20 in the upper housing 10 in the flow direction V in front of the mechanical filter 3 .

The first and second electrodes 22, 24 of the ionizer 20, designed as plate electrodes, are connected via an electrically conductive connection (not shown) to a high-voltage source designed as a controllable and in 1 connected only schematically shown power supply module 7, which the first and second electrodes 22, 24 of the ionizer 20 with a high electrical voltage (DC voltage) of, for example, 3 kV to 10 kV applied. The third electrode 26 is connected to electrical ground. A constant, lower DC voltage of 1000 V, for example, is present between the second electrodes 24 of the ionizer 20 and the third electrode 26 provided inside the mechanical filter 3 . An electrically positive voltage measured against ground is therefore present both at the first electrodes 22 and at the second electrodes 24, with this positive voltage at the first electrodes 22 being higher than the positive voltage at the second electrodes 24.

Thus, despite lower voltages than in conventional systems, there is a strong electric field (typically up to 900 kV/m) due to the relative potentials of the electrodes 22, 24 within the ionizer 20 and another, weaker field between the entire ionizer 20 and the third Electrode 26 inside the mechanical filter 3, which accelerates the particles charged in the ionizer 20 in the direction of the mechanical filter 3 and thus separates them there.

As in 2 As can be seen, the plates of the first electrodes 22 are shorter than the plates of the second electrodes 24 in the flow direction (V) of the air to be cleaned, with the longer plates of the second electrodes 24 in the upstream direction and in the downstream direction over the plates of the first electrodes 22 stand out. The shorter plates of the first electrodes 22 are shortened in relation to the longer plates of the second electrodes 24 on both sides in the direction of flow by a dimension of approximately 2.5 to 3 times the lateral plate spacing a. The plate spacing a can be 7 mm to 14 mm, for example.

On the (in the flow direction of the air to be cleaned) front and back sides of the shorter ones Plates of the first electrodes 22 are attached electrically conductive needle extensions 28 which extend in the downstream direction and/or in the upstream direction beyond the plate edge of the respective plate. The length of the respective needle extension is, for example, 0.7 times the plate spacing between adjacent first and second electrodes 22, 24. The distance between the needle extensions of a plate is, for example, at least 1.5 times the plate spacing between adjacent first and second electrodes Electrodes 22, 24.

Reference signs in the claims, the description and the drawings are only intended for a better understanding of the invention and are not intended to limit the scope of protection.

reference list

1

air purification unit

2

electrostatic precipitator module

3

mechanical filter module

4

Sensor for monitoring the amount of anions

5

Sensor for monitoring the ozone level

6

UV light source

7

power supply module

10

upper case

11

air intake

12

lower case

20

ionizer

21

first electrostatic filter stage

22

first electrodes

23

second electrostatic filter stage

24

second electrodes

25

passage

26

third electrode

27

cylinder wall

28

needle extension

30

mechanical filter element

31

HEPA filter

32

radially outer entry surface

33

air outlet channel

34

exit surface

V

flow direction

V'

flow direction

QUOTES INCLUDED IN DESCRIPTION

This list of the documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• US4056372A [0003]
• US5330559A [0003]

Claims (10)

Air cleaning unit with at least one electrostatic filter module (2) through which the air to be cleaned can flow, which has at least one first electrode (22) and at least one second electrode (24), between which the air to be cleaned flows and between which by applying a power supply module (7 ) provided electrical high voltage, an electrical field can be generated, with the electric filter module (2) in the flow direction (V) of the air to be cleaned a mechanical filter module (3) with at least one mechanical filter element (30), which is preferably used as a particle or suspended matter filter, for example as a HEPA filter, is arranged downstream, characterized in that in the mechanical filter element (30) or in the mechanical filter module (3) behind the mechanical filter element (30) at least one third electrode (26) is provided, with between the at least one second electrode (24) and the at least one third electrode (26 ) an electric field can be generated by applying an electric voltage. air cleaning unit after claim 1 , characterized in that the at least one first electrode (22) and the at least one second electrode (24) are designed as plate electrodes. air cleaning unit after claim 2 , characterized in that the at least one first electrode (22) designed as a plate electrode is shorter in the flow direction (V) of the air to be cleaned than the at least one second electrode (24) also designed as a plate electrode, the at least one second electrode (24) extends beyond the plate of the at least one first electrode (22) in the downstream direction and/or in the upstream direction. air cleaning unit after claim 2 or 3 , characterized in that the at least one first electrode (22) has at least one electrically conductive needle extension (28) which is located essentially in the plane of the plate and extends in the downstream direction and/or in the upstream direction over the plate edge of the first electrode (22). extends beyond. Air cleaning unit according to one of the preceding claims, characterized in that the at least one third electrode (26) is connected to the electrical ground and that both the at least one first electrode (22) and the at least one second electrode (24) have a counter Measured against ground, positive voltage is applied, the positive voltage at the at least one first electrode (22) being higher than the positive voltage at the at least one second electrode (24). Air cleaning unit according to one of the preceding claims, characterized in that the at least one third electrode (26) is tubular and is arranged in a tubular air outlet channel (33) of the ring-cylindrical mechanical filter element (30). Air cleaning unit according to one of the preceding claims, characterized in that in operation between the at least one first electrode (22) and the at least one second electrode (24) there is a controllable DC voltage and in that in operation between the at least one second electrode (24) and the at least one third electrode (26) a constant DC voltage is applied. Air cleaning unit according to one of the preceding claims, characterized in that in the flow direction (V) of the air to be cleaned behind the arrangement of the at least one first electrode (22) and the at least one second electrode (24) at least one sensor (5) for monitoring the Ozone content of the air is provided. Air cleaning unit according to one of the preceding claims, characterized in that in the flow direction (V) of the air to be cleaned behind the arrangement of the at least one first electrode (22) and the at least one second electrode (24) at least one sensor (4) for monitoring the Anion amount is provided. Air purification unit according to one of the preceding claims, characterized in that the magnitude of the electrical voltage which is present between the at least one first electrode (22) and the at least one second electrode (24) is dynamically determined by regulation.

Images