AT527089A1 - Oil mist separator - Google Patents

Abstract

Filter system (1) for separating liquid accompanying substances in the form of droplets or mist from a gaseous material flow, comprising a housing (2) in which a filter insert (5) is arranged, the housing (2) having an inlet (11) and an outlet (12) for the material flow, the filter insert (5) having a plurality of filter layers (7) which are arranged substantially parallel to one another, the filter layers (7) being arranged in the housing (2) in such a way that a material flow entering through the inlet (11) enters the filter layers (7) at the front, the housing (1) having (a) a front section (21) in which the inlet (11) is arranged; (b) has a rear portion (23) in which the outlet (12) is arranged and (c) has a middle portion (22) between the front portion (21) and the rear portion (23) in which the filter layers (7) of the filter insert (5) are arranged substantially vertically.

Description

OIL MIST SEPARATOR

The invention relates to a filter system for separating liquid accompanying substances in the form of droplets or mist from a gaseous material flow, comprising a housing in which a filter insert is arranged, the housing having an inlet and a

Outlet for the material flow. Background of the invention

Oil mist separators are used to treat gaseous material flows to remove liquid fractions in the form of droplets or mist. In the state of the art, different filter systems are used for this purpose, which are based on different physical principles. Centrifugal separators are often used in which droplets that have a higher mass than the gas flow itself are separated by centrifugal action.

become.

Filter systems of this type have filter media in which the droplets get stuck and then collect in the housing as a liquid fraction. The advantage of filtering separators is the consistently high defined separation efficiency depending on the filter media used. However, the installation space required in such filter systems to keep the pressure loss low is high. Therefore, the use of such filter systems in the state of the art is limited to non-mobile applications such as stationary gas engines or stationary

diesel engines.

A first approach to improving such filter systems is described in US 9,272,236 B2, in which the filter system has several filter layers that are arranged in a housing in such a way that the material flow enters the filter layers at the front and flows through the filter insert. This design not only shows a higher separation efficiency with less installation space, but also a longer service life compared to filter systems in which the filter layers are stacked and the material flow hits the filter layers at the front and flows through the filter layers layer by layer. In US 9,272,236 B2, the filter layers are installed in such a way that they lie horizontally in the housing. This arrangement has a positive effect on the material flow, which can flow optimally through the filter medium, so that the pressure drop through the filter medium is lower.

In addition, the drainage of the separated liquid downwards is promoted.

Although the filter system according to US 9,272,236 B2 has a long service life with high filter performance and low installation height compared to other filter systems, there is still a need for filter systems in which the time in which one can filter without interruption (service life) is even longer. This is particularly important in areas of application in which the replacement of the filter medium is associated with a high level of work and/or where the

Stopping the filter system leads to a production stoppage. Brief description of the invention

The object of the present invention is therefore to improve a filter system of the type mentioned at the outset in such a way that the service life is improved. This object is achieved by a filter system for separating liquid accompanying substances in the form of droplets or mist from a gaseous material flow, comprising a housing in which a filter insert is arranged, wherein the housing has an inlet and an outlet for the material flow, wherein the filter insert has several filter layers which are arranged essentially parallel to one another, wherein the filter layers are arranged in the housing in such a way that a material flow entering through the inlet enters the filter layers at the front, characterized in that the housing

(a) having a front portion in which the inlet is disposed;

(b) has a rear portion in which the outlet is arranged and

(c) has a central section between the front and rear sections,

in which the filter layers are arranged essentially vertically.

It has been shown that the filter system according to the invention with a vertical arrangement of the filter layers in the housing enables an improved separation performance with a longer service life. Above all, such a filter system has the following advantages over US 9,272,236 B2:

Advantage that the separation efficiency is greater with longer operating times.

In order for the material flow to enter the filter layers optimally, the front section can be provided with an empty space, whereby the empty space extends essentially over the entire height of the filter layers. The inlet is arranged in the front section in the area of the empty space. The front empty space allows the material flow to be distributed homogeneously over the entire height of the filter layers and then evenly into the individual

filter layers.

The rear section can also have a void, with the void extending essentially over the entire height of the filter layers. This leads to a lower pressure loss in the filter system. The outlet is in the rear section in the area of the void

arranged.

The inlet is equipped with a source for the gaseous stream, which contains liquid, droplet-

or mist-like accompanying substances.

for the front section in the area of the empty space. The front empty space allows the material flow to be distributed homogeneously over the entire height of the filter layers

and then evenly enter the individual filter layers.

The rear section can also have a void, with the void extending essentially over the entire height of the filter layers. This leads to a lower pressure loss in the filter system. The outlet is in the rear section in the area of the void

arranged.

Preferably, the inlet in the housing is arranged at a first height and the outlet in the housing is arranged at a second height, wherein the first height is below the second height

is.

The height of the housing is preferably at least twice the width of the housing.

In one embodiment, at least one holding element for the filter layers is provided between the front section and the middle section and/or at least one holding element for the filter layers is provided between the rear section and the middle section. This embodiment ensures that the filter layers remain in the middle section and are not pushed into the front or rear section. The holding elements are arranged in such a way that the

filter layers are prevented.

In a variant, for example, it may be provided that the respective

Holding element is selected from the group consisting of strut, grid plate, perforated plate or

Combinations of these. The simplest and most cost-effective variant is at least one strut (e.g. as a cross strut or longitudinal strut), which also has the advantage that the pressure loss caused by the surface of the holding elements is minimized. A grid plate or a perforated plate is also suitable for supporting the filter layers in the middle section

and still allow the material flow to enter the filter layers.

It is preferably provided that the filter insert forms at least one stack of individual filter layers, preferably packed essentially without gaps, wherein the flow direction of the material flow is essentially parallel to the interfaces of the filter layers. In this way, the separation performance is maximized because the material flow can penetrate the filter layers better. As a rule, at least five essentially parallel, adjacent filter layers are provided. In a preferred embodiment, the filter insert comprises two stacks of filter layers.

When using two stacks of filter layers, one stack is a pre-filter and one stack is a fine filter of filter material. The pre-filter is primarily used to catch splash oil, i.e. liquid drops of oil, whereas the fine filter carries out the actual filtration of mist-like oil. The materials of the two stacks can be different, but do not have to be. A glass fiber fabric, which has a lower filtering effect than the fine filter, has proven to be advantageous as a pre-filter. This is accompanied by a lower pressure loss. There should be a spatial separation or interruption of the two stacks. This means that the oil that has already penetrated cannot completely penetrate the pre-filter stack and subsequently also cannot enter the filing filter.

be pressed.

The filter layers are preferably made of mineral fibers and are several centimeters thick.

The mineral fibres have a long-threaded structure.

Furthermore, the adjacent filter layers can be arranged offset. The offset arrangement of the filter layers can increase the inlet and outlet area for the material flow. This can also reduce the inlet pressure resistance and promote the outflow of the aggregated liquid at the outlet area. The filter layers can be arranged offset by a distance from each other on the inlet and outlet side for the material flow. The distances can be

Exit side can also be selected differently or can only be used at entry or only

at the outlet, an offset can be provided. The filter layers can also be arranged alternately offset so that a tooth profile results. The filter layers can also be arranged at least partially offset. The offset is preferably between 50

and 150% of the thickness of the respective filter layer.

It is particularly preferred that the filter layers are compressible, whereby the filter layers are introduced into the housing with pre-tension. The pre-tension describes a permanently acting compression force which is applied along the thickness of the filter layers and serves, among other things, to arrange the filter fibers partially parallel to the direction of the gas flow. It is also necessary that after the filter layers have been introduced into

the housing permanently maintains a pre-stress on the filter layers.

Compressible filter layers are those that have a first volume in the relaxed state, whereby the filter layers can take up a second volume that is smaller than the first volume through compression. In this context, pre-stressed means that the filter layers are compressed in the housing, whereby an external force acts on the filter layers. The external force reduces the volume to a second volume and the respective filter layer has an internal stress. When the external force is removed, the internal stress causes the filter layer to expand again. Such pre-stressed filter layers have a high

separation efficiency and ensure a small installation space.

In one embodiment, the housing has an upper cover and a lower cover, with the upper cover covering the filter layers on the upper side and the lower cover covering the filter layers on the lower side, with the filter layers being glued to the upper cover and to the lower cover. In this way, the

The flow of material past the edge of the housing is reduced.

The filter system preferably has an oil outlet in the rear section, whereby the oil outlet is connected to an oil reservoir, whereby the highest point of the oil reservoir is below the oil outlet. The height difference must be selected accordingly in order to prevent oil from being sucked back into the oil outlet. This ensures that in the

Oil separated from the filter medium is separated and discharged from the filter system.

In order to prevent oil from flowing back or gas being sucked in from the oil reservoir, a siphon can be installed between the oil outlet and the oil reservoir. This siphon can be constructed as a pipe-in-pipe siphon or in the classic form of a horizontal S-shaped pipe or hose. The distance or height difference of the siphon to the filter base must be selected in such a way that the prevailing suction pressure in the filter system prevents it from being sucked dry. A siphon is only to be used if there is no continuous drainage hose return below the

Oil levels in the oil reservoir are expected.

Such filter systems are suitable, for example, for internal combustion engines, in particular gas engines or diesel engines, but also for other areas in which liquid accompanying substances in the form of droplets or mist are to be filtered out of a gaseous material flow. For example, ventilation systems in kitchens can be mentioned. Therefore, the invention also relates to: e an internal combustion engine, preferably a gas engine or diesel engine, comprising a filter system of the aforementioned type; e a ventilation system for a kitchen, comprising a filter system of the aforementioned type; or

e a pump comprising a filter system of the aforementioned type.

Detailed description of the invention

Fig. 1 shows a filter system according to the state of the art

Fig. 2 shows a variant of the filter system according to the invention in oblique view (Fig. 2a) and in side view (Fig. 2b)

Fig. 3 shows an oblique view of the filter system according to the invention from Fig. 2 in the open state

Fig. 4 shows a holding element for the filter layers for the filter system of Fig. 2 and 3

Fig. 5 shows the lower cover of the filter system of Fig. 2 and 3

Fig. 6 shows a filter system in the opened state including the filter insert for the invention in section (Fig. 6a) and in oblique view (Fig. 6b).

Fig. 7 shows a filter system with siphon.

7117

In Fig. 1, a filter system 1 according to the prior art according to US 9,272,236 B2 is shown. The filter system 1 according to the prior art comprises a housing 2 in which a filter insert 5 is arranged, wherein the housing 2 has an inlet 11 and an outlet 12 for the material flow, wherein the filter insert 5 has several filter layers 7 which are arranged essentially parallel to one another. The filter layers 7 are arranged horizontally in the housing 2. A

The material flow entering through the inlet 11 can enter the filter layers 7 at the front.

Fig. 2a and 2b show two views of a filter system 1 according to the invention for separating liquid accompanying substances in the form of droplets or mist from a gaseous material flow. The filter system 1 comprises a housing 2 in which a filter insert 5 (see Fig. 6a and 6b) is arranged. In addition, the housing 2 has an inlet 11 and an outlet 12 for the material flow. The flow direction of the material flow is indicated by arrows. The inlet 11 is arranged in the housing 2 at a first height and the outlet 12 is arranged in the housing 2 at a second height, the first height being below the second height. In simple terms, the inlet 11 is below the

Outlet 12 is arranged.

The height of the housing 2 is more than twice as large as the width of the housing 2 —- in the embodiment shown, about three times as large. This design increases the

Separation performance even further.

The housing 2 comprises an upper cover 14 and a lower cover 15, wherein the upper cover 14 and the lower cover 15 cover the filter layers 7 in the closed state. The filter layers 7 are glued to the upper cover 14 and to the lower cover 15 (not shown). For this purpose, it is advantageous if the inner surface of the respective cover is roughened (see Fig. 5, in which the inside, i.e. the inner surface of the

lower cover 15).

In the rear section 23 of the housing 2, an oil outlet 19 is arranged through which

collected liquid can be drained. Fig. 6 shows a variant of the filter insert 5 in the housing 2 in section (Fig. 6a)

and in oblique view (Fig. 6b), whereby the filter insert 5 in this embodiment has two stacks

with several filter layers 7. The filter layers 7 are arranged in each stack in

Arranged essentially parallel to one another. The housing 2 forms the housing for the filter insert 5. As indicated by the four cross arrows in Fig. 6a, the filter layers 7 are subjected to a prestress on both sides along their thickness. The filter layers 7 are compressible, so that the filter layers 7 are compressed in the housing 2 due to the prestress, since the prestress applies a permanently acting compression force along the thickness of the filter layers 7. As a result, the filter fibers are arranged partially parallel to the direction of the gas flow. The housing 2, which forms a housing for the filter insert 5, thus permanently applies a prestress to the filter layers 7. Such prestressed filter layers 7 have a high separation efficiency and

ensure a small installation space.

The filter layers 7 are arranged in the housing 2 in such a way that a material flow entering through the inlet 11 enters the filter layers 7 at the front. The filter insert 5 is designed as at least one stack of individual filter layers 7, preferably packed essentially without gaps, wherein the filter insert 5 is arranged in such a way that the flow direction of the material flow is essentially parallel to the interfaces 8 of the filter layers 7. With two stacks of filter layers 7 - as shown in Fig. 6a and 6b - the material flow first enters the first stack and then the second stack. In the embodiment shown, several, essentially parallel, adjacent filter layers 7 are provided in two stacks, wherein the adjacent filter layers 7 are arranged offset in each of the stacks. The offset arrangement of the filter layers 7 allows the entry and exit area for the material flow to be increased. This also reduces the inlet pressure resistance and promotes the outflow of the aggregated liquid at the outlet surface. In the embodiment shown in Fig. 6a and 6b, the filter layers 7 are arranged alternately offset in each stack, so that a tooth profile is produced for each stack. The filter layers 7 can also be arranged at least partially offset. The offset is preferably between 50 and 150% of the thickness of the respective filter layer 7.

In Fig. 3, the opened housing 2 is shown, which has a front section 21 in which the inlet 11 is arranged. In addition, a rear section 23 is provided in which the outlet 12 is arranged. The middle section 22 is between the front section 21 and the rear section 23 in which the filter layers 7 of the filter insert

5 are arranged substantially vertically.

The front section 21 has an empty space, the empty space extending essentially over the entire height H of the filter layers 7. Between the front section 21 and the middle section 22, a holding element 25 for the filter layers 7 is shown in simplified form in Fig. 3, which prevents the filter layers 7 from moving sideways. Between the rear section 23 and the middle section 22, a holding element 26 for the filter layers 7 is also provided. The holding elements 25, 26 can - as shown in Fig. 4 - be designed, for example, as a perforated sheet. In Fig. 3, the holding elements 25, 26 are shown in simplified form as a surface. Instead of a perforated sheet, struts could also be used.

be provided.

As shown in Fig. 7, the oil outlet 19, which can be connected to an oil reservoir, with the highest point of the oil reservoir being below the oil outlet 19, can be followed by a siphon 20. The siphon 20 is arranged between the oil outlet 19 and the oil reservoir in order to prevent a backflow from the oil reservoir or a bypass of unfiltered gas flow into the housing 2. All components of the oil drainage and thus also the oil reservoir are preferably sealed against the environment. This prevents the suction of

Prevents external air.

Claims (10)

Claims 1. Filter system (1) for separating liquid accompanying substances in the form of droplets or mist from a gaseous material flow, comprising a housing (2) in which a filter insert (5) is arranged, the housing (2) having an inlet (11) and an outlet (12) for the material flow, the filter insert (5) having a plurality of filter layers (7) which are arranged substantially parallel to one another, the filter layers (7) being arranged in the housing (2) in such a way that a material flow entering through the inlet (11) enters the filter layers (7) at the front, characterized in that the housing (1) (a) has a front portion (21) in which the inlet (11) is arranged; (b) has a rear portion (23) in which the outlet (12) is arranged and (c) a middle section (22) between the front section (21) and the rear section (23) in which the filter layers (7) of the filter insert (5) are arranged essentially vertically. 2. Filter system according to claim 1, characterized in that the front section (21) has a void, the void extending substantially over the entire height (H) the filter layers (7). 3. Filter system according to claim 1 or claim 2, characterized in that between the front section (21) and the middle section (22) holding elements (25) for the filter layers (7) are provided and / or that between the rear section (23) and the middle section (22) holding elements (26) for the filter layers (7) are provided. 3. Filter system according to claim 3, characterized in that the holding elements (25, 26) are selected from the group consisting of cross brace, grid sheet, perforated sheet or Combinations thereof. 4. Filter system according to one of claims 1 to 3, characterized in that the filter insert (5) forms at least one stack of individual filter layers (7) which are preferably packed essentially without gaps, the filter insert (5) being arranged in such a way that the flow direction of the material flow is essentially parallel to the boundary surfaces (8) of the filter layers (7). 5. Filter system according to one of claims 1 to 4, characterized by at least five essentially parallel, adjacent filter layers (7). 6. Filter system according to one of claims 1 to 5, characterized in that the filter layers (7) comprise compressible material, wherein the filter layers (7) in the housing (2) are inserted with pre-stress. 7. Filter system according to one of claims 1 to 6, characterized in that the housing (2) has an upper cover (14) and a lower cover (15), wherein the upper cover (14) and the lower cover (15) cover the filter layers, wherein the filter layers are glued to the upper cover (14) and to the lower cover (15). 8. Filter system according to one of claims 1 to 7, characterized in that an oil outlet (19) is arranged in the rear section (23), wherein the oil outlet (19) is connected to an oil reservoir, wherein the highest point of the oil reservoir is below the oil outlet (19) lies. 9. Filter system according to claim 8, characterized in that between the oil outlet (19) and oil reservoir a siphon is arranged. 10. Internal combustion engine, preferably gas engine or diesel engine, or Ventilation systems for a kitchen or pump, comprising a filter system according to one of the Claims 1 to 9.