WO1991012416A1

WO1991012416A1 - Filter body for filtering a gas stream, especially for purifying exhaust gases issued by an internal combustion engine

Info

Publication number: WO1991012416A1
Application number: PCT/HU1991/000005
Authority: WO
Inventors: Sándor KAPÁS; László CSERNAVÖLGYI; Ágoston MAYER; Béla GALAMBOS
Original assignee: Kapas Sandor; Csernavoelgyi Laszlo; Mayer Agoston; Galambos Bela
Priority date: 1990-02-07
Filing date: 1991-02-07
Publication date: 1991-08-22
Also published as: HUT56297A; HU900692D0; HU206839B; AU7239291A

Abstract

The present invention refers to a filter body for filtering a gas stream, especially for purifying exhaust gases issued by an internal combustion engine, comprising an inlet (1) for receiving a gas stream to be purified, an outlet (4) for discharging the purified gas stream, a chamber (2) having a casing (7) determining an inner surface and at least one filter member (3) of inherent porosity arranged within the chamber (2), the inlet (1) and outlet (6) being determined by closing plates (6), wherein according to the present invention the filter member (3) is made of an active material comprising inner channel shaped openings for receiving the gas stream and within the chamber (2) directing plates (10) are arranged, further in the chamber (2) each directing plate (10) is partly connected and partly disconnected with the inner surface of the casing (7), and each disconnection determines spacings (5), wherein the sum of the cross-sectional areas of the spacings (5) is equal with or greater than the cross-sectional area of the outlet (4).

Description

FILTER BODY FOR FILTERING A GAS STREAM. ESPECIALLY FOR PURIFYING EXHAUST GASES ISSUED BY AN INTERNAL COMBUSTION ENGINE

FIELD OF INVENTION

The present invention refers to a filter body filte body for filtering a gas stream, especially for purifyin exhaust gases issued by an internal combustion engine comprising an inlet for receiving a gas stream to b purified, an outlet for forwarding purified gas stream, chamber having a mantle determining an inner surface and a least one filter member of inherent porosity arranged withi the chamber, wherein the inlet and the outlet are determine by respective closing plates. The filter body can be applie for retaining coal and other harmful components present i an exhaust gas mixture, especially of exhaust gases issue by an internal combustion engine. It is capable of receivin different organic and lead compounds and can be used als for purifying end gases of industrial plants.

BACKGROUND OF THE INVENTION

The exhaust gases issued by the interna^"l combustio engines and the majority of industrial plants contai different components which are injurious to health of huma beings and to the biologic life, the environment, especiall when they are present in high amounts. The active carbo black produced by the diesel engines is a very importan source of pollution and in case of internal combustio engines working with petrol the high amounts of lea compounds are very dangereous. So are the organic compound issued by the engines. Because of this circumstances the purification of the exhaust gases has been a very important task since long time.

The organic lead compounds can be filtered by specific catalyzator means or issuance of them can be avoided by application the unleaded petrol. The latter requires use of a catalyzator body which is sophisticated and relatively expensive.

The issuance of carbon black by the diesel engines causes also serious problems and many solutions have become known for expelling it from the exhaust gases. Among others the firm ZEUNA - Starker (Augsburg, FRG) produces a filter body comprising ceramic plates as filtering elements. The chamber receiving the ceramic plates is fitted to the exhaust pipe of the internal combustion engine. The surface of the filtering elements determine channeling ways for the exhaust gases, the channeling ways are parallel to one another and to the direction of the flow of the gaseous stream. The channeling ways are each from one side closed by ceramic closing members. The latter can receive a part of the carbon black and they make the gaseous stream flow through the ceramic plates. The carbon black particles remain in the ceramic plates and make them inactivated in a relatively short time. The ceramic plates can be regenerated by taking it out from the chamber and firing. In this way the coal particles (i.e. the carbon black) are combusted. The chamber throttles the engine by remarkable diminishing the speed of flow, thus it results in a reduction of the power of the engine. Even with regard to the high number of the vehicles taking part in the road traffic the increase of the pollution level causes series problems because the pollutimg components are injurious to health of the drivers and the passengers. Hence, the tendency can be be observed that air introduced into the inner space of the vehicle is rather filtered. The filtering elements applied to this aim consist of cotton kind textile material from which inserts of low filtering effectivity (capability) are made.

SUMMARY OF THE INVENTION

The object of the invention is to elaborate a solution whereby the requirements concerning filtering in connection with the road traffic and especially purifying the exhaust gases produced by the internal combustion engines and industrial plants can be satisfied better than in the known solutions and thereby it is possible to elaborate solutions meeting the environmental requirements.

Hence, the aim of the present invention is to create a filter body which can be applied on the outlet of an arrangement issuing to the environment gaseous mixtures which include organic and inorganic polluting components, especially on the outlet of the exhaust pipe of an internal combustion engine and/or on the inlet of an air transporting channel communicating with the inner space of the vehicle and which is capable of offering an improved filtering capacity, gives no remarkable throttling, so is not capable of deteriorating the working conditions of an internal combustion engine.

The invention is based on the recognition that the gaseous stream should be purified and filtered by a material having loosely packed structure, showing inherent absorption features and causing no throttle in the way of the flow, a material advantageously based on zeolite.

The object of the invention is therefore a filter body for filtering a gas stream, especially for purifying exhaust gases issued by an internal combustion engine, comprising an inlet for receiving a gas stream to be purified, an outlet for forwarding purified gas stream, a chamber having a mantle determining an inner surface and at least one filter member of inherent porosity arranged within the chamber, wherein the inlet and outlet are determined by closing plates. The most important features of the filter body proposed by the invention are that the filter member is made of an active material comprising inner channel shaped openings for receiving the gas stream and within the chamber directing plates are arranged, further in the chamber each directing plate is partly connected and partly disconnected with the inner surface of the mantle, and each disconnection determines a respective spacing, wherein the sum of the cross—sectional areas of the spacings is equal with or greater than the cross-sectional area of the outlet. The active material is preferably zeolite and more preferably the nature mineral form zeolite.

In the filter body according to the invention the mantle advantageously constitutes an axial symmetric body having longitudinal axis arranged perpendicular to the closing plates, the inner surface of the mantle forming a symmetric shaped body, especially a parallelepiped.

The filter body realized according to the invention operates thereby that it makes the gas stream to be purified flow in a highly turbulent stream. This can very effectively be ensured it the directing plates are arranged under an angle differing from 90°, especially under angle 40 to 50° with regard to the longitudinal axis of the mantle. The directing plates do not contact one another, and may be not parallel with one another.

The effectiveness of the application of the filter body proposed by the present invention is very high in a preferred embodiment, characterized by that the directing plates constitute the filtering members, the filtering members are made with screen plates, e'specially pierced plates clamped in a rigid frame, wherein the screen plates determine an inner space filled out with the active material. In this case it is especially advantageous to make use of guiding members receiving the filtering members arranged on the inner space of the mantle whereby it is possible to exchange and secure the filtering members. The filter body of the invention can be a replaceable and renewable unit when it is realized according to an especially preferred embodiment so that it comprises a single filter member made by a filtering element arranged within the chamber around the outer surface of the mantle, the filtering element determining the outlet, wherein the mantle is made of a pierced or a sieve plate and the filtering element is closed by sieve plates at the inlet and the outlet and in given case the mantle has the shape and dimensions whereby it can be pushed onto an exhaust pipe of an engine. The effectiveness of filtering can further be improved if advantageously the filter member and more exactly its filtering element is arranged within the chamber divided from the inner surface of the chamber by a clearance and it is covered by a pierced or sieve plate on its surface communicating with the clearance. The pierced or sieve plates are generally the kinds of plates prepared by any technology which show at least limited rigidity, shape consistency and wherethrough a gaseous medium can flow without remarkable throttle.

The polluting compounds of relatively low molecular weight and components in shape of small particles can effectively be retained by the filter body built up according to the invention if some and generally at most two directing plates at the outlet form auxiliary filter members made of active coal.

The active material of the filter body of the invention can be consisted of different natural minerals and other substances of high specific surface and porosity, but zeolite is most preferred, and especially natural fibrous zeolite comminuted to particles of about 5 to 8 mm size.

By the means of the filter body of the invention it is possible to filter out the majority of the polluting components of (particles and compounds present in) exhaust gases issued by an internal combustion engine or technologic units of an industrial plant because it offers improved absorption conditions with regard both organic and inorganic polluting components. The filter body can be changed and regenerated without specific difficulties, it is of simple construction, so the application is not linked any way with specific user problems when applied either in a vehicle having internal combustion engine or in appropriate points of an industrial technology.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be further described on the basis of preferred embodiments shown by way of example only and with reference to the attached drawings. In the drawings Fig. 1 shows the side view of a cross-section of a preferred embodiment of the filter body of the invention, the cross-section illustrated taken along a longitudinal axis, Fig. 2 is the cross-section of the filter body of Fig. 1 perpendicular to the longitudinal axis and

Fig. 3 is a side view of the cross-section of another preferred embodiment of the filter body proposed by the invention.

DETAILED DESCRIPTION OF THE INVENTION AND PREFERRED EMBODIMENTS

The filter body proposed by the invention comprises a chamber 2 communicating with an inlet 1. The inlet 1 may be connected with the exhaust system of an internal combustion engine. Within the chamber 2 oppositely to the inlet 1 an outlet 4 is arranged (Figs 1 and 3) . Closing plates 6 are assigned to the inlet 1 and the outlet 4, between them there is a mantle 7 determining an inner surface within the chamber 2. In the inner space of the chamber 2 directing plates 10 are arranged and they, in given case their inner structure and/or their surface areas constitute a way of flow of a gaseous mixture comprising components to be filtered out between the inlet 1 and the outlet 4. It is important that the directing plates 10 do not form any throttling element, i.e. the filter body of the invention is not an element which acts against the exhaust system of the arrangement issuing the gaseous mixture. The directing plates 10 are connected at a part of their periphery with the inner surface determined by the mantle 7 within the chamber 2, they are supported at this part on the mantle 7 and on the remaining part of the periphery they are divided by respective spacings 5 from the inner surface of the mantle 7. As mentioned, the directing plates 10 do not form a throttling element. This is ensured thereby that the summarized cross—sectional area of the spacings 5 is generally not less then the cross-sectional area of the outlet 4.

The chamber 2 is advantageously equipped with closing plates 6 arranged in parallel. Perpendicularly to these closing plates 6 a longitudinal axis can be determined and this is the symmetry axis of both the mantle 7 and chamber 2 which are preferably axial symmetric bodies (Fig. 2) .

Within the chamber 2 in the space between the inlet 1 and the outlet 4 the directing plates are not perpendicular to the longitudinal axis they are arranged under an angle about 45° with respect to this axis. If the mantle 7 and/or the chamber 2 do not form axial symmetric boides, the mentioned angle of inclination of the directing plates 10 can be determined with respect to a straight line connecting the inlet 1 and outlet 4. The cross—sectional area of the spacings 5 can be different at each directing plate, but as mentioned the sum of these areas should be rather greater than the cross-sectional area of the outlet 4. By the arrangement the directing plates 10 it is advantageous to realize the spacings 5 alternatively, i.e. two adjacent spacings 5 lye on the opposite sides of the inner surface of the mantle 7. This or similar arrangements result in a remarkable increase of the length of the way of flow of the gaseous mixture introduced through the inlet 1. The gaseous mixture is made thereby flow from inlet 1 to inlet 4 at least partly oblong the surface of the directing plates 10. In Figures l and 3 the directing plates 10 are shown as parallel elements but this is only a preferred embodiment, they can be arranged also in another way, e.g. not parallel to one another or they can form a series of elements lying perpendicular to one another and having spacings 5 between their ends which lye in the inner space of the chamber 2 detached from the inner surface of the mantle 7. This arrangement results in a relatively long chamber 2 which is advantageous in purifying industrial end gases. Of course, other possibilities of arranging the directing plates can be chosen, too. The filter body of the invention is shown here in more detail in two basic embodiments, which are not the exclusive or the only possibilities of realizing. In Figures 1 and 2 the embodiment is illustrated wherein the directing plates 10 form themselves filter members 3 including an active material for filtering, purifying the gaseous mixture. As it is shown in Fig. 2 the filter member 3 is arranged in guiding means 8 which form respective frames for receiving the plate kind filter members 3 on the inner surface of the mantle 7, of course, except the surface part limiting the spacing 5. It is preferred to apply a rigid frame also in the filter member 3, which rigid frame gives a fixation of sieve plates 9 and between the sieve plates 9 the active material of the filter member 3 is arranged. The active material is a natural mineral or a material received by an appropriate technologic process, which material or mineral has great specific surface and inherent channel type structure for forwarding the gaseous mixture. The investigations proved the best results with application of zeolite. The active material is applied generally in comminuted or in particulate form and it can be closely packed in the space determined by the sieve plates 9 by the means of vibration. The frame of the filter members 3 offers the possibility that the latter can be replaced in the guiding means 8, they can be taken out for regeneration and new ones can be inserted for replacing the filter members 3 which are exhausted.

According to another preferred embodiment of the invention shown in Fig. 3 the filter member 3 is a single body. This is made also of an active material of great specific surface, of inherent inner channel type structure for forwarding the gaseous mixture. The active material in this case can be also a fibreous material consisted of particles of zeolite or other natural mineral. The filter member 3 surrounds an outer surface of the mantle 7, it is divided from the inner surface (outer wall) of the chamber 2 by a clearance 12. The filter member 3 communicates at one end with the inlet 1 and at its other end, wherein the inner space determined by the end part of the mantle 7 is at least partly covered by one of the closing plates 6, the outlet 4 is realized. In this case at least the majority of the directing plates 10 is made of an appropriate metal or other rigid material withstanding the corrosive effects of the gaseous mixture introduced into the chamber 2 through the inlet 1. In this proposed embodiment the mantle 7 is realized also in form which facilitates the connection of the proposed filter body of the invention with the exhaust system of an internal combustion engine or with an exhaust pipe forwarding the end gases of an industrial plant. The exhaust system is represented by 11 on Fig. 3.

In the embodiment shown in Fig. 3 the filter member 3 is covered advantageously from each side but in any case from the side of the mantle 7 and at the inlet 1 and the outlet 4 by a pierced plate or rigidly clamped sieve plate 9 allowing free communication between the space of flow of the gaseous mixture and inner space of the filter member 3. Hence, the most advantageous is to apply a filter member 3 covered also on the side of the clearance 12 with a pierced plate or a sieve plate 9.

Several of the directing plates 10 can be realized on the basis of active coal. This is especially preferred in that way that two last of them before the outlet 4 are made with sieve plates 9 receiving in the space limited thereby the active coal. This directing plate 10 renders possible to filter out and bind the majority of fine particles present in the gaseous mixture and many compounds of small molecular weight. According to the experience gained with the filter body of the invention it is preferred to apply four directing plates 10 within the chamber 2 as filter members 3 or rigid directing plates 10 and to introduce two directing plates 10 which form auxiliary filter members 3 before the outlet 4 and are made of active coal.

The advantage of application of zeolite is that this active material can be simply regenerated by firing at temperatures about 600 °C.

In the filter member(s) 3 of the application the active material is e.g. the natural zeolite, especially the zeolite distributed by the Madi Asvanybanyak (Mad, Hungary) which shows absorbing capacity about 30 % and includes about 75 to 80 % by weight silica. The rest mainly consists of alumina and the composition is completed by ferrous oxide, magnesium oxide, calcium oxide and natrium oxide. The zeolite is generally applied in the form of particles 5 to 8 mm which can be packed by the means of vibration and the packed material can be easily kept together by the sieve plates 9 or pierced plates. The zeolite as a natural fibrous material is characterized by great specific surface and inherent channel type structure.

The filter body of the invention operates as follows: The exhaust gas introduced into the filter body of the invention through the inlet 1 and it is made flow not along a direct way to the outlet 4 but oblong the surface of the directing plates 10. Hence, its stream enters the inner space of the filter member(s) 3. Because of the spacings 5 the gaseous mixture flows from the inlet 1 to the outlet 4 in a turbulent stream. The turbulent stream penetrates into the filter member(s) 3 through the openings of the sieve plates 9 or pierced plates limiting the surface of the filter member(s) 3 and remains in a free communication with the active material over relatively long time. The active material binds the particulate components and the different organic and inorganic chemical compounds present in the gaseous mixture, they are absorbed on the inner and outer surfaces of the particles of the active material. So it can be observed that the very dangerous lead compounds remain in great part also in the active material. If applied, by the means of the auxiliary filter member(s) 3 further filtering can be assured, the active coal is capable of binding some particles and compounds differing from those which remain within the active material of the filter member(s) 3.

The spacings 5 between the inner surface of the mantle 7 ensure that the filter body realized according to the present invention do not form a throttle on the way of flow of the gas stream, hence, the filter body of the invention does not cause any remarkable decrease of the power of an internal combustion engine, if applied on the outlet of the exhaust system of a such engine. The clearance 12 plays also a limited role in ensuring the low resistance way of flow. The filter body of the invention is very effective in expelling components which are injurious to the environment. The filter member(s) 3 can be regenerated by firing. The invention can be realized in the form of replaceable and renewable units.

Claims

WHAT WE CLAIM IS :

1. A filter body for filtering a gas stream, especially for purifying exhaust gases issued by an internal combustion engine, comprising an inlet (1) for receiving a gas stream to be purified, an outlet (4) for forwarding purified gas stream, a chamber (2) having a mantle (7) determining an inner surface and at least one filter member (3) of inherent porosity arranged within the chamber (2), the inlet (1) and outlet (6) being determined by closing plates (6) , characterized in that the filter member (3) is made of an active material comprising inner channel shaped openings for receiving the gas stream and within the chamber (2) directing plates (10) are arranged, further in the chamber (2) each directing plate (10) is partly connected and partly disconnected with the inner surface of the mantle (7) , and each disconnection determines spacings (5) , wherein the sum of the cross—sectional areas of the spacings (5) is equal with or greater than the cross-sectional area of the outlet (4) .

2. The filter body according to claim 1 , charac¬ terized in that the mantle (7) constitutes an axial symmetric body having longitudinal axis perpendicular to the closing plates (6) , the inner surface of the mantle (7) forming an axial symmetric shaped body, advantageously a parallelepiped.

3. The filter body according to claim 2 , charac¬ terized in that the directing plates (10) are arranged with regard to the longitudinal axis of the mantle (7) under an angle differing from 90°, especially under angle 40 to 50°.

4. The filter body according to any of claims 1 to 3, characterized in that the directing plates (10) constitute the filtering members (3), wherein the filtering members (3) are made with screen plates, especially pierced plates clamped in a rigid frame, wherein the screen plates determine an inner space filled out with the active material.

5. The filter body according to claim 4 , charac¬ terized in comprising guiding members arranged on the inner space of the mantle (7) for exchanging and clamping the filtering members (3) .

6. The filter body according to any of claims 1 to 3 , characterized in comprising a single filter member (3) made by a filtering element arranged around the outer surface of the mantle (7) within the chamber (2) , the filtering element determining the outlet (4) , wherein the mantle (7) is made of a pierced plate or a sieve plate (9) and the filtering element is closed by sieve plates (9) at the inlet (1) and the outlet (4) .

7. The filter body according to claim 6 , charac- terized in that the filter member (3) is arranged within the chamber (2) divided from its inner surface by a clearance (12) and it is covered by a pierced plate or a sieve plate (9) on its surface communicating with the clearance (12) .

8. The filter bddy according to any of claims 1 to 7, characterized in that the at most two directing plates (10) at the outlet (4) form auxiliary filter members (3) made with active coal.

9. The filter body according to any of claims 1 to 8, characterized in that the mantle (7) is made fittable to an exhaust pipe of an engine.

10. The filter body according to any of claims 1 to 9 , characterized in that the filter member(s) (3) consist(s) of zeolite, especially natural zeolite comminuted to particles of about 5 to 8 mm size.