Patent Grant
10807108
The present disclosure relates to fluid spray injectors, e.g., for selective catalyst reduction systems that inject urea/diesel exhaust fluid for use with diesel or other suitable engines.
Certain selective catalyst reduction (SCR) systems (e.g., for NOx reduction) require a controlled injection of diesel exhaust fluid (DEF) or urea into the exhaust system. This fluid needs to evaporate and mix rapidly before entering a catalyst. The injectors that are used for this injection are run on a duty-cycle to control the amount of DEF in the exhaust and are operated very frequently with short cycles. However, typical pressure-swirl atomizers require a refractory period of time before the full spray cone develops, resulting in good atomization. During this refractory period the liquid effluent is temporarily very poorly atomized.
With a constant “on/off” cycle, much of the liquid injected is poorly atomized. If the spray takes a relatively long time to develop, then a significant portion of the duty-cycle could be spent developing the spray, resulting in slugs of fluid (or large droplets) being formed each cycle. Thus, these systems can suffer from unevaporated DEF depositing on the catalyst or other parts of the system resulting in fouling of the catalyst by formation of urea crystals.
Such conventional methods and systems have generally been considered satisfactory for their intended purpose. However, there is still a need in the art for improved injectors with rapid spray development. The present disclosure provides a solution for this need.
In certain embodiments, a fluid spray nozzle tip can include a feed hole body that defines at least one feed hole and a spray outlet, the at least one feed hole being in direct fluid communication with the spray outlet without also being in fluid communication with an upstream spin chamber. The at least one feed hole can be a plurality of feed holes, wherein the tip further includes a pintle sealing surface body extending from the feed hole body and configured to allow a pintle to seal against a sealing surface thereof.
The spray outlet can have a constant cross sectional area over a full longitudinal dimension of the spray outlet. The spray outlet can be cylindrical.
The spray outlet can be defined through pintle sealing surface body and partly into the feed hole body. The feed holes can be defined at a non-normal angle relative to a centerline axis (forward or backward in a longitudinal direction of the centerline) of the nozzle tip where the at least one feed hole intersects with the spray outlet. The feed holes can be at normal angle relative to a centerline axis to meet the spray outlet. The feed holes can be straight.
The feed holes can be offset from centerline of the spray outlet to cause swirling in spray outlet. Each feed hole can intersect at least one other feed hole in addition to intersecting with the spray outlet.
Each feed hole can define a feed hole axis and the spray outlet defines a spray outlet axis, wherein the feed hole axis is skewed relative to the spray outlet axis.
The pintle sealing surface body can define a flange having a larger dimension from the centerline than the feed hole body. The spray outlet can effuse from the pintle sealing surface body.
The feed holes can be recessed inwardly from the sealing surface such that the sealing surface extends at least partially over the feed holes. The feed holes can have a non-linear shape. The non-linear shape can be a tentacle shaped.
The feed hole body can be integral with the pintle sealing surface body. The feed hole body can be shaped to be surrounded by a pintle to allow the pintle to seal against the pintle sealing surface to prevent flow to the feed holes. The sealing surface body can include a cavity configured to receive a pintle to allow the pintle to interact with the pintle sealing surface to prevent flow to the feed holes.
In accordance with at least one aspect of this disclosure, a fluid spray nozzle tip can include a feed hole body that defines a plurality of feed holes and a pintle sealing surface body extending from the feed hole body and configured to allow a pintle to seal against a sealing surface thereof. At least one of the feed hole body and the pintle sealing surface body define a spray outlet in direct fluid communication with the plurality of feed holes without an upstream spin chamber.
The spray outlet can have a constant flow area. For example, the spray outlet can be cylindrical. Any other suitable shape for the spray outlet is contemplated herein.
In certain embodiments, the spray outlet can be defined through pintle sealing surface body and partly into the feed hole body. The feed holes can be defined at a non-normal angle relative to centerline axis of the nozzle tip to meet the spray outlet. In certain embodiments, the feed holes can be defined at normal angle relative to centerline axis to meet the spray outlet.
In certain embodiments, the feed holes can be straight. Any other suitable shape (e.g., a non-linear flow channel) is contemplated herein. The feed holes can be offset from centerline to cause swirling in spray outlet.
The pintle sealing surface body can define a flange having a larger dimension from the centerline than the feed hole body. The spray outlet can spray from the pintle sealing surface body.
In certain embodiments, the feed holes can be recessed from sealing surface such that sealing surface extends over the feed holes. In certain embodiments, the feed holes have tentacle shape, however, any suitably shaped flow channels are contemplated herein.
In certain embodiments, the feed hole body can be integral with the pintle sealing surface body. It is contemplated that the feed hole body and the pintle sealing surface body can be separate pieces joined together in any suitable manner.
The feed hole body can be shaped to be surrounded by a pintle to allow the pintle to interact with the pintle sealing surface to prevent flow to the feed holes. In certain embodiments, the sealing surface body can include a cavity configured to receive a pintle to allow the pintle to interact with the pintle sealing surface to prevent flow to the feed holes.
In accordance with at least one aspect of this disclosure, a fluid spray nozzle includes a housing defining a flow cavity, any suitable embodiment of a nozzle tip as described above and disposed at an end of the housing, and a pintle disposed within the flow cavity and configured to axially actuate therein between an open position where the feed holes are in fluid communication with the flow cavity, and a closed position where the pintle interacts with the pintle sealing surface to seal the feed holes from the flow cavity. The nozzle tip can be integral with the housing in certain embodiments.
These and other features of the systems and methods of the subject disclosure will become more readily apparent to those skilled in the art from the following detailed description taken in conjunction with the drawings.
So that those skilled in the art to which the subject disclosure appertains will readily understand how to make and use the devices and methods of the subject disclosure without undue experimentation, embodiments thereof will be described in detail herein below with reference to certain figures, wherein:
Reference will now be made to the drawings wherein like reference numerals identify similar structural features or aspects of the subject disclosure. For purposes of explanation and illustration, and not limitation, an illustrative view of an embodiment of a nozzle tip in accordance with the disclosure is shown in
Referring to
The spray outlet 109 can be centrally located (e.g., coaxial with the centerline of the tip 100) or in any other suitable position. The spray outlet 109 can include any suitable opening edge 111 (e.g., sharp to cause narrower spray angle, angled (beveled) edge for wider spray angle). The spray outlet 109 can have a constant flow area. For example, the spray outlet 109 can be cylindrical. Any other suitable shape and/or dimensions (e.g., 1 to 1 diameter to length) for the spray outlet 109 is contemplated herein.
As shown, in certain embodiments, the spray outlet 109 can be defined through pintle sealing surface body 105 and partly into the feed hole body 101. As shown in
As shown in
The pintle sealing surface body 105 can define a flange having a larger dimension from the centerline than the feed hole body 101. The spray outlet 109 can spray from the pintle sealing surface body 105 as shown in
Referring now to
In certain embodiments, the feed holes 303 have a non-linear shape (e.g., tentacle shape with curves in one or more dimensions), however, any suitably shaped flow channels are contemplated herein. The feed holes 303 can meet the outlet 109 offset from the centerline to cause swirling in the outlet 109 and/or can be meet at a normal angle or at any suitable tilt angle.
Referring to
As shown in
In accordance with at least one aspect of this disclosure, referring to
In certain embodiments, the nozzle tip 103 can be integral with the housing 417. For example,
As described above, feed holes directly intersect the spray orifice at the upstream end, without a spin-chamber, which allows rapid development of a swirling flow-field and a corresponding conical spray. Feed holes offset from the centerline can create spin for atomizing quickly. Embodiments include a single piece structure that has a single orifice that causes swirling and spraying. Certain embodiments can be additively manufactured which can allow for any suitable structures and flow channels.
Certain embodiments provide a means to very rapidly form a fully-developed conical spray. This can be particularly advantageous in applications where the injector (spray) is duty-cycled on and off, frequently (e.g., in SCR NOx reduction systems). Typical pressure-swirl atomizers have offset holes/slots which feed an upstream spin-chamber to establish a swirling flow-field, which then passes through a smaller diameter orifice and forms a finely atomized conical spray. Filling this spin-chamber and establishing the swirling flow-field takes time, and during this time the spray may or may not be conical and is typically very poorly atomized. Embodiments eliminate the spin-chamber and feed offset holes/slots directly into the orifice. This permits very rapid spray cone development with good atomization. Embodiments can be used as swirler for any suitable system and is not limited to use in SCR systems, or even for rapid spray development.
The methods and systems of the present disclosure, as described above and shown in the drawings, provide for spray nozzles with superior properties. While the apparatus and methods of the subject disclosure have been shown and described with reference to embodiments, those skilled in the art will readily appreciate that changes and/or modifications may be made thereto without departing from the spirit and scope of the subject disclosure.
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| Entry |
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| Extended European Search Report of the European Patent Office, dated Sep. 13, 2018, in corresponding European Patent Application No. 18181620.8. |
| Number | Date | Country | |
|---|---|---|---|
| 20190022673 A1 | Jan 2019 | US |
