GB2298592A

GB2298592A - Apparatus for the treatment of circuit gas of a circulatory diesel plant

Info

Publication number: GB2298592A
Application number: GB9604979A
Authority: GB
Inventors: Freerk Meyer
Original assignee: Thyssen Nordseewerke GmbH
Current assignee: Thyssen Nordseewerke GmbH
Priority date: 1995-03-10
Filing date: 1996-03-08
Publication date: 1996-09-11
Anticipated expiration: 2016-03-08
Also published as: GB2298592B; GB9604979D0; DE29504137U1

Description

Apparatus for the treatment of circuit gas of a circulatory diesel plant The invention relates to an apparatus for the treatment of the gas supplied to a diesel engine, in particular in a marine craft, wherein the gas which at least principally comprises air or oxygen has preferably been pretreated by passing it through an absorber to free it of carbon dioxide, the apparatus comprising a housing having a gas inlet and a gas outlet, deflection means for changing the direction of the gas within the interior of the housing and a water outlet as set forth in the preamble to claim 4 and also to an apparatus in accordance with the preamble of claim 1.

Apparatus of this kind is used as a separator for the treatment of recirculated gas or circuit gas.

By way of example it has been proposed to design a hovercraft in which the air cushion is generated by a diesel engine and the air in this air cushion is also used for the combustion air for the diesel engine. The exhaust gas is also used for the air cushion and the diesel engine takes the combustion air from the air cushion so that the exhaust gases are not vented directly into the atmosphere. One reason for doing this is to prevent the detection of the exhaust gases through infrared detectors.

Because the combustion air, i.e. the intake air, is contaminated with exhaust gases, due to it being recirculated via the air cushion, it is necessary to clean the combustion air before it is supplied to the combustion chambers of the diesel engine.

A similar situation arises with diesel powered submarines.

With circulatory diesel engines it is not only necessary for the circuit gas to be dry at the engine inlet but rather also to have a low soot content in order that the required service lives can be achieved. In circulatory diesel plants the exhaust gas is mixed in an absorber with sea water so that carbon dioxide, which has arisen from combustion in the engine, can be washed out of the circuit gas. However, the cleaned circuit gas then leaves the absorber with a relatively high proportion of water. In order to reduce the proportion of water the circuit gas is deflected within a subsequent separator of the initially named kind and the water is thereby separated out in the form of water droplets. In addition, the separator serves to protect the engine against overflowing water from the absorber.If, namely, a quantity of water which is too large enters into the separator then rapid closure flaps in the circuit gas system are actuated in order to protect the engine. The separator must be able to accommodate a sufficient quantity of water in dependence on the reaction time of the flaps.

In circulatory plants in accordance with the prior art soot is filtered out of the circuit gas in a mesh filter arranged after the separator. The soot consists of small particles which, in a moist environment, join together to form a sticky mass. Filters already used in practice must therefore be dismantled and cleaned, for example after 50 to 60 operating hours.

Sought is an apparatus of the initially named kind, which additionally satisfies the following objects and conditions: Objects: 1. To be able to dry the circuit gas, separate out water and remove water from the system.

2. To prevent water hammer in the diesel engine through overflowing of the absorber and to form a reservoir for overflowing water.

3. To filter soot out of the circuit gas.

Boundary conditions: 1. The filter should not have to be removed during a mission (ca. 350 operating hours).

2. The gas flow resistance may not be too high.

3. The treated circuit gas must be so clean that it does not contaminate the diesel engine.

This is achieved by an apparatus with the features set forth in the claims.

The essential advantage of the invention is to be seen in the fact that the functions of a separator and of a soot filter are carried out in a single housing, with long periods of operation being achieved. If effects of contamination show at the filter then the filter can be cleaned during operation.

The invention will now be described with reference to the accompanying drawings by way of example. In the drawings there are shown Figure 1: a schematic longitudinal section through an apparatus in accordance with the invention, Figure 2: a cross-section through the filter of Figure 1 in the plain II of Figure 1, and Figure 3: a plan view on the top of the apparatus of Figure 1 as seen in the direction of the arrow III.

In the drawings a substantially cylindrical housing is shown with the reference numeral 10 into which water and circuit gas contaminated with soot is introduced at 11. It will be noted that the gas inlet 11 feeds the gas tangentially into the cylindrical housing of the filter and the gas is caused to flow in a rotating movement around the axis 27 of the filter and housing through the cylindrical chamber 26. The housing thus acts in a manner similar to a cyclone. During this rotating movement water droplets or other particulates are caused to move outwardly by centrifugal force and then drop under gravity into the conical base 28 of the filter housing.Thus, the gas executes a rotational movement in the interior 26 of the housing and finally encounters change of direction parts or deflection parts in the lower part of the housing which are generally designated with the reference numeral 13. The circuit gas is deflected there through substantially 1800 and passes generally upwardly along the axis 27 of the housing. Through this procedure water passes downwardly through the perforated metal sheet 13 and can be led away via a water outlet 15, optionally into a water container.

The circuit gas thereby passes into the interior space of a filter 20, which is a cylindrically shaped mesh filter insert. The filter insert 20 is located within a cylindrical inner housing 28, which is spaced from the cylindrical outer housing wall 29 to define the cylindrical chamber 26. The inner housing 28 projects at the top of the apparatus beyond the top of the outer housing and the gas outlet 12 is connected to the inner housing above the top of the outer housing. Thus the circuit gas and combustion gas pass radially outwardly through the filter insert 20 into the chamber 30 provided between the filter insert 20 and the inner housing 28 and from this chamber into the gas outlet 12. The filter insert 20 is connected to a plate 21, which can be rotated about the axis 27 of the housing and of the filter insert.This rotation is effected by the crank handle, which is illustrated generally by the reference numeral 22. This handle can be turned by hand, which results in rotation of the plate 21 and of the filter about the axis 27.

In use the filter will become more and more blocked by particulate material, frequently in the form of wet sticky particulate material in the circuit gas. A cleaning device is provided for the cleaning of the filter. This cleaning device comprises a spray bar or tube 31, which extends in Figure 1 down the left-hand side of the inner housing within the cylindrical space 30 between the inner housing 28 and the filter 20 parallel to the axis of the filter insert over substantially the full length of the filter insert. The spray bar 31 has nozzles 32 through which water is sprayed radially inwardly through the filter insert. As can be seen from Figure 2, an impact plate 24 and also brushes 33 are mounted within filter insert 20. The impact plate 24 and brushes are of fixed location and are mounted on a support 34 secured to the apparatus at the base 35 of the truncated conical section 28. As can be seen from Figure 2, the impact plate 24 is of V-shape prosection and faces towards the spray bar and spray nozzles 32. In this way cleaning water sprayed radially inwardly through the wall of the filter insert impinges on the impact plate and is deflected so that it can drain downwardly through the bottom of the filter insert within the impact plate 24 and subsequently through the apertured sheet metal plate 13 to the water outlet 15.

One the one hand this prevents the water been caught up with the rising gas, and on the other hand it also prevents the water sprayed through the radial wall of the filter insert from striking the opposite wall and undesirably pushing particulates through the opposite wall so that they could pass out of the gas outlet 12.

The brush 33 helps remove loose particles from the insert and also improves the cleaning action.

Water which drains from the outer side of the filter insert 20 falls under the action of gravity to the bottom of the inner housing 28 and passes there through a drain tube 36 directly into the space beneath the apertured plate 13 into the cylindrical chamber 37, from which it can drain through the water outlet 15.

In operation, if the filter insert 20 is to be cleaned, then water under a high pressure is introduced into the spraying bar 31 via a cleaning water inlet 23 and, as is schematically indicated, sprays from the outside via nozzles onto the filter insert 20. The impact plate 24 and also the brushes, which are both of fixed location, are arranged in this embodiment inside the filter insert 20. If the filter insert is turned during this cleaning process via the parts 22 then soot can be cleaned off from the filter and removed via the water outlet 15.

Although in this arrangement the spray bar is arranged radi ally outside of the filter and the impact plate and brushes are arranged radially inside of it with the gas flow to be filtered passing radially outwardly through the filter it is also possible to conceive an inverted arrangement in which the gas to be cleaned passes radially inwardly through the filter insert and the spray bar is arranged inside the filter insert to spray water radially outwardly through the same. This would mean that the gas outlet 12 would have to communicate with the interior of the filter insert, which could, for example, be realized by a tube extending upwardly through the filter insert and having its opening spaced from the plate 21. The tube would then, for example, be led out through the conical wall at the base of the outer housing.

Although, for reasons of simplicity, the rotation of the filter insert during cleaning is preferably effected by hand, it is also entirely conceivable to provide a motor for this purpose and indeed such a drive could also operate at the base of the filter insert 21.

If the gas is filtered by allowing it to pass radially inwardly through the filter element 20 then the gas outlet 12 could also be provided in the plate 38 at the top of the housing and communicate with the interior of the filter via apertures (not shown) provided in the plate 21. An arrangement of this kind would be possible irrespective of whether the filter insert 20 is driven from the top or the bottom, provided that the layout of the filter is appropriately chosen, for example to prevent collision between the crank handle and the gas outlet.

With an excessive water entry from the absorber a water level sensor 25 responds. The volume above this sensor is selected such that no water can enter through 12 into the circuit gas system prior to closure of the quick closure flaps, which are, for example, provided downstream of the gas outlet 12.

Claims

What we claim is:

1. Apparatus for the treatment of the circuit gas of a circulatory diesel plant, preferably in water vehicles, comprising a housing with a gas inlet and a gas outlet, deflection parts for the circuit gas in the interior of the housing, a collection container for water and a water outlet at the housing, characterized by a mesh filter insert (20) in the form of a cylinder provided in the housing (10) downstream of the deflection parts (13) for the circuit gas and by a filter cleaning device (22, 23, 24), which can be actuated from the outside.

2. Apparatus in accordance with claim 1, characterized in that the filter cleaning device is formed by a water injection device (23) arranged radially outside of the mesh filter insert (20) and an impact plate (24) with cleaning brushes arranged radially within the mesh filter insert (20).

3. Apparatus in accordance with one of the claims 1 or 2, characterized in that the mesh filter insert (20) is rotatably mounted and is rotatable about its axis during the cleaning process, preferably by hand.

4. Apparatus for the treatment of the gas supplied to a diesel engine, in particular in a marine craft, wherein the gas which at least principally comprises air or oxygen has preferably been pretreated by passing it through an absorber to free it of carbon dioxide, the apparatus comprising a housing having a gas inlet and a gas outlet, deflection means for changing the direction of the gas within the interior of the housing and a water outlet, characterized in that a filter in the form of a cylinder is provided in the housing downstream of the deflection means for the gas with the gas to be filtered passing either radially inwardly or radially outwardly through the filter and by a filter cleaning device which can be periodically actuated to clean the filter.

5. Apparatus in accordance with claim 4, characterized in that the cleaning device comprises a water injection device arranged radially outside of the filter when the gas to be filtered flows radially outwardly through the filter or arranged inside the filter when the gas to be filtered flows radially inwardly through the filter.

6. Apparatus in accordance with claim 5, characterized in that a means is provided for rotating the filter about its axis during the cleaning process.

7. Apparatus in accordance with claim 6, characterized in that an impact plate and/or cleaning brushes is or are arranged on the radially opposite side of the cylindrical filter from the water injection device.

8. Apparatus in accordance with claim 7, characterized in that the water injection device comprises an elongate spray bar on the one side of the filter, with the impact plate and/or brushes being arranged in a corresponding elongate arrangement opposite to the spray bar, with the rotation of the filter permitting the full volume of the filter to be cleaned during one rotation thereof past the spray bar and the impact plate and/or brushes.

9. Apparatus in accordance with any one of the preceding claims, characterized in that means is provided to permit water injected through the filter to drain downwardly and be extracted through the water outlet.

10. Apparatus in accordance with any one of the preceding claims, characterized in that the gas inlet is arranged to direct the combustion air in a rotating flow around the filter axis within the filter housing in the manner of a cyclone for the separation of water droplets and/or particulates from the combustion air prior to directing the combustion air through said filter.

11. Apparatus substantially as here described and illustrated with respect to the accompanying drawings.

11. Apparatus in accordance with claim 10, characterized in that the housing comprises a generally cylindrical outer housing and a generally cylindrical inner housing disposed within the inner housing and spaced therefrom to form a cylindrical space into which said gas inlet opens in a generally tangential direction; in that said inner housing projects upwardly above said outer housing and is open at the bottom so that gas entering through said gas inlet can pass downwardly through said cylindrical space and into said open base of said inner housing; in that said cylindrical filter insert is provided in said inner housing and spaced from it to form a further cylindrical space, with said open base of said inner housing communicating with the inside of said filter insert and with said gas outlet communicating with said further cylindrical space and being positioned above said outer housing, so that gas passing through said filter insert into said further cylindrical space can pass through said gas outlet; and in that said filter insert is mounted at its upper end to a rotable plate.

12. Apparatus in accordance with claims 8 and 11, characterized in that said spray bar is disposed within said further cylindrical space and said impact plate and/or brushes is/are disposed within said filter insert opposite to said spray bar.

13. Apparatus substantially as here described and illustrated with respect to the accompanying drawings.

Amendments to the claims have been filed as follows 1. Apparatus for the treatment of the gas supplied to a diesel engine, wherein the gas which at least principally comprises air or oxygen has preferably been pretreated by passing it through an absorber to free it of carbon dioxide, the apparatus comprising a housing having a gas inlet and a gas outlet, deflection means for changing the direction of the gas within the interior of the housing and a water outlet, characterized in that a filter in the form of a cylinder is provided in the housing downstream of the deflection means for the gas with the gas to be filtered passing either radially inwardly or radially outwardly through the filter and by a filter cleaning device which can be periodically actuated to clean the filter.

2. Apparatus in accordance with claim 1, characterized in that it is adapted for use with a diesel engine in a marine craft.

3. Apparatus in accordance with claim 1 or claim 2, characterized in that the cleaning device comprises a water injection device arranged radially outside of the filter when the gas to be filtered flows radially outwardly through the filter or arranged inside the filter when the gas to be filtered flows radially inwardly through the filter.

4. Apparatus in accordance with claim 3, characterized in that a means is provided for rotating the filter about its axis during the cleaning process.

5. Apparatus in accordance with claim 4, characterized in that an impact plate and/or cleaning brushes is or are arranged on the radially opposite side of the cylindrical filter from the water injection device.

6. Apparatus in accordance with claim 5, characterized in that the water injection device comprises an elongate spray bar on the one side of the filter, with the impact plate and/or brushes being arranged in a corresponding elongate arrangement opposite to the spray bar, with the rotation of the filter permitting the full volume of the filter to be cleaned during one rotation thereof past the spray bar and the impact plate and/or brushes.

7. Apparatus in accordance with any one of the preceding claims, characterized in that means is provided to permit water injected through the filter to drain downwardly and be extracted through the water outlet.

8. Apparatus in accordance with any one of the preceding claims, characterized in that the gas inlet is arranged to direct the combustion air in a rotating flow around the filter axis within the filter housing in the manner of a cyclone for the separation of water droplets and/or particulates from the combustion air prior to directing the combustion air through said filter.

9. Apparatus in accordance with claim 8, characterized in that the housing comprises a generally cylindrical outer housing and a generally cylindrical inner housing disposed within the inner housing and spaced therefrom to form a cylindrical space into which said gas inlet opens in a generally tangential direction; in that said inner housing projects upwardly above said outer housing and is open at the bottom so that gas entering through said gas inlet can pass downwardly through said cylindrical space and into said open base of said inner housing; in that said cylindrical filter insert is provided in said inner housing and spaced from it to form a further cylindrical space, with said open base of said inner housing communicating with the inside of said filter insert and with said gas outlet communicating with said further cylindrical space and being positioned above said outer housing, so that gas passing through said filter insert into said further cylindrical space can pass through said gas outlet; and in that said filter insert is mounted at its upper end to a rotable plate.

10. Apparatus in accordance with claims 6 and 9, characterized in that said spray bar is disposed within said further cylindrical space and said impact plate and/or brushes is/are disposed within said filter insert opposite to said spray bar.