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BR-112023013841-B1 - Powder spraying system, and apparatus and method for treating a filter.

BR112023013841B1BR 112023013841 B1BR112023013841 B1BR 112023013841B1BR-112023013841-B1

Abstract

POWDER SPRAYING SYSTEM AND HEAD, AND APPARATUS AND METHOD FOR TREATING A FILTER. This is a powder spraying system comprising a dry powder source (4), a spraying head (25), and a supply conduit (16) connecting the dry powder source to the spraying head. The spraying head comprises a head body (50) having a head outlet (51), a first conduit (52) for dry powder, and a second conduit (53) for gas. The first conduit extends between a powder inlet (54) communicating with the supply conduit and a powder outlet (55). The second conduit extends between a gas inlet (56) and a gas outlet (57), the gas outlet being situated close to the powder outlet so that a gas flowing through the second conduit and out of the gas outlet produces a suction force at the powder outlet to promote the flow of a dry powder through the first conduit and out of the powder outlet and the head outlet. The powder outlet and the gas outlet are oriented so as to promote the mixing of the gas with the powder (...).

Inventors

  • Thomas HOTCHKISS
  • David MARVELL
  • Craig THOMSON
  • Sabina Burmester

Assignees

  • JOHNSON MATTHEY PUBLIC LIMITED COMPANY

Dates

Publication Date
20260310
Application Date
20220209
Priority Date
20210212

Claims (14)

  1. 1. Powder spraying system, comprising: a) a dry powder source (4); b) a spray head (25); and c) a supply conduit (16) connecting the dry powder source (4) to the spray head (25); wherein the spray head (25) comprises: i) a head body (50) having a head outlet (51); ii) a first conduit (52) for dry powder; (iii) a second gas conduit (53); wherein the first conduit (52) extends between a powder inlet (54) communicating with the supply conduit (16) and a powder outlet (55); wherein the second conduit (53) extends between a gas inlet (56) and a gas outlet (57), wherein the gas outlet (57) is situated close to the powder outlet (55) so that a gas flowing through the second conduit (53) and out of the gas outlet (57) produces a suction force at the powder outlet (55) to promote the flow of a dry powder through the first conduit (52) and out of the powder outlet (55) and the head outlet (51); the powder outlet (55) and the gas outlet (57) being oriented to promote the mixing of the gas with the dry powder; characterized in that the powder spraying system is configured so that the feed from the supply conduit (16) from a terminal part of the dry powder source (4) is carried out by gravity assisted by the suction force generated in the spray head (25) and without the use of a gas flow in the supply conduit (16) to drag the dry powder.
  2. 2. Powder spraying system according to claim 1, characterized in that the powder outlet (55) comprises: a single powder opening; or a plurality of powder openings, each powder opening being associated with the gas outlet of the second conduit; optionally, wherein the, or each, powder opening has an orifice diameter of 0.5 to 5.0 mm, optionally, of 1.0 to 2.5 mm, optionally, of 1.0 to 2.0 mm.
  3. 3. Powder spraying system according to claim 1, characterized in that the head body (50) comprises one or more secondary gas outlets that are spaced from the head outlet (51) and oriented to direct one or more secondary gas flows to impact the gas and dry powder flow exiting the head outlet (51), wherein the impact is external to the head body (50) and at a distance from the head outlet (51); wherein the one or more secondary gas outlets are oriented to direct the one or more secondary gas flows so that their angle of incidence with the gas and dry powder flow exiting the head outlet (51) is from 30 to 90°, optionally from 45 to 75°, optionally from 60°; optionally, wherein the one or more secondary gas outlets comprise 2, 4, 6, 8 or more gas outlets. secondary; optionally, wherein one or more secondary gas outlets form 1, 2, 3, 4 or more pairs of secondary gas outlets, wherein each pair of secondary gas outlets comprises two secondary gas outlets that are situated on opposite sides of the head outlet (51) from each other.
  4. 4. Powder spraying system according to claim 3, characterized in that the head body (50) comprises a third conduit, separate from the second conduit, to supply gas to the secondary gas outlets.
  5. 5. Powder spraying system according to any one of claims 1 to 4, characterized in that the dry powder source (4) is aligned with the first duct (52) of the head body (50), optionally, wherein the dry powder source (4) is coincident with a longitudinal geometric axis of the first duct (52).
  6. 6. Powder spraying system according to any one of claims 1 to 5, characterized in that the supply conduit (16) between the dry powder source (4) and the spray head is straight; and/or in that the spray head (25) is oriented so that the outlet of the head (51) faces downwards and the dry powder source (4) is situated directly above the spray head (25).
  7. 7. Powder spraying system according to any one of claims 1 to 6, characterized in that it further comprises a cleaning head located within the first conduit (52), wherein the cleaning head is connected to a gas supply and has an outlet directed towards the powder outlet (55); and, optionally, wherein the outlet of the cleaning head comprises 1 to 10, optionally, 1 to 3 orifices; and, optionally, the or each orifice has an orifice diameter of 0.5 to 1.5 mm, optionally, of 0.5 mm.
  8. 8. Powder spraying system according to any one of claims 1 to 7, characterized in that the head outlet (51) is located on a first end face of the head body (50) and the powder inlet (54) is located on a second, opposite end face of the head body (50); and/or in that the first conduit (52) is a straight conduit between the powder inlet (54) and the powder outlet (55); and/or in that the first conduit (52) is parallel to, and optionally coincident with, a longitudinal geometric axis of the head body (50).
  9. 9. Powder spraying system according to any one of claims 1 to 8, characterized in that the first conduit (52) comprises an orifice whose internal diameter decreases from a first diameter at the powder inlet (54) to a second diameter at or adjacent to the powder outlet (55).
  10. 10. Powder spraying system according to any one of claims 1 to 9, characterized in that the first conduit (52) comprises an orifice whose internal diameter decreases from a first diameter at the powder inlet (54) to a second diameter at, or adjacent to, the powder outlet (55) exclusively through one or more tapered sections.
  11. 11. Powder spraying system according to any one of claims 1 to 10, characterized in that the head body (50) comprises one or more secondary gas outlets that are spaced from the head outlet (51) and oriented to direct one or more secondary gas streams to impact the dry gas and powder stream exiting the head outlet (51), wherein the impact is external to the head body (50) and at a distance from the head outlet (51); wherein the head body (50) comprises a third conduit, separate from the second conduit, to supply gas to the secondary gas outlets.
  12. 12. Apparatus for treating a filter for filtering particulate matter from the exhaust gas comprising the powder spraying system as defined in any one of claims 1 to 11, characterized in that the apparatus further comprises: (i) a filter holder for holding a filter, wherein the outlet head (51) of the powder spraying head (25) is oriented to spray the dry powder towards an inlet face of the filter; and/or (ii) a vacuum generator in communication with an outlet face of the filter to generate a primary gas flow through the filter, wherein the powder spraying head (25) is situated upstream of the inlet face of the filter and is oriented to spray the dry powder into the primary gas flow upstream of the inlet face of the filter.
  13. 13. Apparatus according to claim 12, characterized in that it further comprises a flow conduit upstream of the inlet face for channeling the primary gas flow towards the inlet face of the filter; and an adapter situated between the flow conduit and the filter; the adapter being configured to adapt the shape and/or size of the flow conduit to the shape and/or size of the inlet face of the filter; optionally, wherein the adapter comprises a tubular body having an upper seal at its upper end and a lower seal at its lower end; and wherein the upper end of the adapter has a first internal diameter adapted to an internal diameter of the lower end of the flow conduit and the lower end of the adapter has a second internal diameter adapted to a diameter of the inlet face of the filter; and, optionally, wherein the first internal diameter of the adapter may be larger or smaller than the second internal diameter.
  14. 14. Method for treating a filter for filtering particulate matter from exhaust gas, the method comprising the steps of: a) containing a dry powder in a dry powder source (4); b) locating a filter in a filter holder, wherein the filter comprises a porous substrate having an inlet face and an outlet face, wherein the inlet face and the outlet face are separated by a porous structure; c) establishing a primary gas flow through the porous structure of the filter by applying a pressure reduction to the outlet face of the filter; d) transferring the dry powder from the dry powder source (4) through a supply conduit (16) and to a spraying device (7) located upstream of the inlet face of the filter; (ee) spraying the dry powder, using the spraying device (7), towards the inlet face of the filter, so that the dry powder is carried in the primary gas flow and passes through the inlet face of the filter to come into contact with the porous structure; characterized in that the feeding of the supply conduit from a terminal part of the dry powder source (4) is carried out by gravity assisted by the suction force generated in the spray head (25) and without the use of a gas flow in the supply conduit (16) to carry the dry powder.

Description

[001] The present disclosure relates to a powder spraying system and a powder spraying head. In particular, the disclosure relates to a powder spraying system and a powder spraying head that can be used as part of an apparatus for, and in a method of, coating a filter comprising a porous substrate having inlet surfaces and outlet surfaces, the inlet surfaces being separated from the outlet surfaces by a porous structure. The filter may be a wall-flow filter, for example, for an emissions control device for an internal combustion engine. BACKGROUND OF THE INVENTION [002] There are concerns about particulate matter (PM) emissions, commonly referred to as soot, from internal combustion engines, and especially from diesel and gasoline engines in automotive applications. The main concerns are associated with potential health effects and, in particular, with very small particles that have sizes in the nanometer range. [003] Diesel particulate filters (DPFs) and gasoline particulate filters (GPFs) have been manufactured using a variety of materials including sintered metal, ceramics, or metallic fibers, etc., with the most common type in mass production being the wall-flow type, produced from porous ceramic material manufactured in the form of a monolithic matrix of many small channels arranged along the length of the body. Alternating channels are closed at one end, so as to force the exhaust gas to pass through the walls of the porous ceramic channels, which prevent the passage of most of the particulate matter, allowing only the filtered gas to enter the environment. Ceramic wall-flow filters in commercial production include those produced from cordierite, various forms of silicon carbide, and aluminum titanate. The actual shape and dimensions of practical filters in vehicles, as well as properties such as the wall thickness of the channels and their porosity, etc., depend on the application in question. The average pore dimensions in the filter channel walls of a ceramic wall flow filter through which the gas passes are typically in the range of 5 to 50 μm and generally around 20 μm. In a quite noticeable contrast, the size of most diesel particulate matter emitted by a high-speed diesel engine in a modern SUV is much smaller, for example, from 10 to 200 nm. [004] Some part of the particulate matter (PM) can be retained within the pore structure in the filter walls and, in some applications, can gradually accumulate until the pores become interconnected by a network of PM, and this PM network then facilitates the formation of a particulate cake on the inner walls of the filter channels. The particulate cake is an excellent filter medium and its presence provides very high filtration efficiency. In some applications, the soot is continuously burned in the filter as it is deposited, preventing a particulate cake from accumulating in the filter. [005] For some filters, for example, particulate filters for light-duty diesel engines, it is periodically necessary to remove trapped particulate matter from the filter to prevent excessive backpressure buildup, which is detrimental to engine performance and can result in high fuel consumption. Thus, in diesel applications, the trapped particulate matter is removed from the filter by being burned in the air in a process during which the amount of available air and the amount of excess fuel used to achieve the high temperature required to ignite the trapped particulate matter are carefully controlled. At the end of this process, which is generally called regeneration, the removal of the last remaining particulate matter in the filter can lead to a sharp decrease in filtration efficiency and the release of a burst of many small particles into the environment. Thus, filters may have low filtration efficiency when they are first used and subsequently after each regeneration event, and also during the last part of each regeneration process. [006] Thus, it would be desirable to improve and/or maintain filtration efficiency at all times - for example, during the initial life of a filter when it is used for the first time and/or during regeneration and immediately afterwards, and/or when the filter is loaded with soot. [007] Liu, X., Szente, J., Pakko, J., Lambert, C. et al., “Using Artificial Ash to Improve GPF Performance at Zero Mileage”, SAE Technical Paper 2019-01-0974, 2019, DOI:10.4271/2019-01-0974 describes a process for loading a “bare” (uncoated) filter substrate with submicron-sized alumina particles generated by an atomizer to create an “artificial ash” coating to reduce soot emissions during cold start conditions. The process involves generating aerosol particles by atomizing a liquid suspension with compressed air, drying the resulting ash containing droplets by passing it through an oven, and loading the dried ash particles onto the filter by capturing them through filtration. The process utilizes a high-capacity atomizer (model PLG-2100, PALAS, Germany) to delive