Spray nozzle

A spray nozzle which employs a locking and an alignment feature to facilitate the replacement of internal nozzle components. The spray nozzle includes a nozzle body, a swirl element and an orifice disc. The nozzle body defines a central bore which extends between a fluid receiving section and a fluid discharge section and delineates a central axis and delimits an interior locating surface for swirl element and the orifice disc. The orifice disc includes a protuberance associated with the downstream surface thereof which protrudes into the spray opening of the nozzle body.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The subject invention relates to spray nozzles for use in spray drying applications, and more particularly to, spray nozzles of the type which employ locating and/or wear part retention/locking features to facilitate ease of replacement and handling of internal nozzle components and the reinstallation of the assembled unit in the nozzle location.

2. Background of the Related Art

Fluid nozzles or atomizers having a spiral swirl chamber and a spray orifice disposed within a nozzle body have been employed in the past for various applications, including spray drying, aeration, cooling, and fuel injection. U.S. Pat. No. 3,680,793 to Tate, which is herein incorporated by reference in its entirety, discloses a spray nozzle that includes a swirl chamber configured such that the origin of the spiral flow in the swirl chamber and the spray orifice formed in the orifice disc are eccentrically offset relative to each other. The spray orifice and the spiral flow origin were eccentrically offset from each other so as to improve the spray patternation in both large and small spray nozzle applications.

Spray drying is the transformation of a feed liquid from a fluid state into dried particulate form by spraying atomized feed into a gaseous drying medium. The liquid feed can be either a solution, suspension, dispersion, emulsion or slip. Often, the liquid feed contains abrasive solids. The atomization of the feed is accomplished by a spray nozzle. The nozzle must disperse the liquid into small droplets, which should be well distributed into the air stream and also serve as the metering device for the feed system.

In applications such as spray drying, the energy for atomization is supplied solely by the liquid feed pressure with inlet pressures typically exceeding 5,000 psi and occasionally reaching 10,000 psi. Due to the high inlet pressure, the liquid feed passes through the flow passages of the spray nozzle at a high velocity. Liquid feed containing abrasive solids and traveling at a high flow velocity causes erosion of the flow passages in the swirl chamber and orifice disc. As a result, the swirl chamber and orifice disc need to be replaced somewhat routinely.

In most nozzles, replacement of the internal components first requires the removal of the nozzle assembly from the fluid delivery system. Then an adapter which is normally threadably secured to the nozzle body must be disengaged. The adapter functions to secure the internal components, namely the swirl chamber, orifice disc and O-ring seals (adapter and orifice), within the nozzle body. The adapter also facilitates the axial alignment of the swirl chamber by providing a recess for the swirl chamber in its down stream end. Next an adapter seal, which is disposed between the adapter and the swirl chamber is removed. At this point, the remainder of the internal components can be freely removed.

Reassembling the spray nozzle is accomplished by reversing the disassembly procedure. However, difficulty is often encountered when attempting to engage the nozzle body, including the orifice disc and associated O-ring, with the adapter. Generally, the adapter is placed on a flat surface and the orifice disc is placed on top within the alignment recess. The nozzle body with orifice disc disposed therein is also placed on a flat surface with the discharge orifice facing down. In order to assemble the nozzle, either the adapter or the nozzle body have to be inverted. However, when inverting either the nozzle body or the adapter to engage the parts, the internal components unseat, become misaligned and often fall out.

There is a need therefore, for a spray nozzle which facilitates replacement of worn internal components by proving a mechanism for aligning and securing the internal components prior to engagement of the adapter with the nozzle body.

SUMMARY OF THE INVENTION

The subject application is directed to a new and improved spray nozzle which includes a nozzle body, a swirl element and an orifice disc. The nozzle body has opposed upstream and downstream end portions. The upstream end portion includes a fluid receiving section and the downstream end portion includes a fluid discharge section and defines a spray opening for emitting an atomized spray therefrom. The nozzle body defines a central bore which extends between the fluid receiving section and the fluid discharge section and delineates a central axis and delimits an interior locating surface for the nozzle.

The swirl element is disposed within the central bore of the nozzle body and is positioned adjacent to the fluid receiving section. The swirl element has a peripheral surface and defines an interior swirl cavity. Preferably, the peripheral surface has an upstream and a downstream portion, the downstream portion being configured for slidable engagement with the locating surface of the nozzle body. The upstream portion has a fluid inlet formed therein to provide a path for fluid to communicate between the fluid receiving section of the nozzle body and the interior swirl cavity of the swirl element.

The interior swirl cavity of the swirl element is defined by an approximately curvilinear surface for imparting a spiral flow to the fluid passing therethrough and includes a fluid outlet for discharging the spiral flow therefrom. Additionally, in a preferred embodiment, the swirl element further includes a recessed surface formed in the upstream portion of the peripheral surface for facilitating fluid flow between the upstream portion of the peripheral surface and the nozzle body. In one embodiment, the recessed surface formed in the peripheral surface of the swirl element has a trapezoidal axial cross-section.

In an alternate embodiment, the swirl element further includes a tapered neck portion associated with an upstream end thereof. The tapered neck portion, by providing a smooth transition, facilitates the communication of fluid between the fluid receiving portion of the nozzle body and fluid inlet of the swirl element. The tapered neck portion also prevents material blockages from forming within the internal flow path and reduces the pressure loss across the nozzle assembly.

The orifice disc is also disposed within the central bore of the nozzle body and is positioned upstream of the fluid discharge section. The orifice disc includes axially opposed upstream and downstream surfaces which define a peripheral surface therebetween. The peripheral surface is configured for slidable engagement with the interior locating surface of the nozzle body.

A spray orifice extends between the opposed upstream and downstream surfaces and is in fluid communication with the fluid outlet of the swirl cavity and the discharge section of the nozzle body. It is presently envisioned that the orifice disc has a protuberance associated with the downstream surface thereof which projects into the spray opening of the nozzle body and prevents the incorrect orientation of the disc. In a preferred embodiment, the protuberance has a chamfered downstream edge which facilitates the insertion of the protuberance into the spray opening of the nozzle body.

It is envisioned that the spray nozzle further includes an adapter member which is engaged with the upstream end portion of the nozzle body so as to contain the orifice disc and swirl element within the bore of the nozzle body. Preferably, the upstream end portion of the nozzle body has male threads associated therewith for engagement with corresponding female threads associated with the adapter member.

Preferably the central bore of the nozzle body further includes a second interior locating surface having two radially opposed recesses formed therein. The second interior surface is positioned radially outward of the interior locating surface so as to facilitate the communication of fluid between the upstream portion of the swirl element peripheral surface and the nozzle body.

In a preferred embodiment, the spray nozzle of the present disclosure further includes a locking plate disposed within the central bore of the nozzle body and positioned upstream of the swirl element. The locking plate is rotatably engaged within radially opposed recesses formed in the central bore of the nozzle body. It is envisioned that the recesses are formed in a plane which passes through the central axis of the nozzle at a right angle. In an alternate embodiment, the recesses are angled with respect to a plane passing through and perpendicular to the central axis. As a result, the rotational engagement of the locking plate with the recesses increases a contact pressure applied by the locking plate to the swirl element. It is presently preferred that the locking plate also includes a tool engaging portion which facilitates the rotational engagement of the locking plate within the recesses.

Alternatively, the spray nozzle disclosed herein can include a retainer element in lieu of the locking plate. The retainer element is also disposed within the central bore of the nozzle body and positioned upstream of the swirl element. The retainer element includes a retainer disc and a seal member. The retainer disc has opposed upstream and downstream planar surfaces and a peripheral surface extending therebetween. A groove formed in the peripheral surface and the seal member is disposed within the groove. The seal member engages with a corresponding recess formed in the central bore of the nozzle body so as to secure the retainer element, swirl element, and orifice disc within the central bore of the nozzle body. In a preferred embodiment, the retainer disc includes flow apertures formed therein which extend between the opposed upstream and downstream planar surfaces. The flow apertures providing for fluid communication between the fluid receiving portion of the nozzle body and the upstream portion of the swirl element peripheral surface.

The present disclosure is also directed to an orifice disc for a spray nozzle which includes a nozzle body. The nozzle body has opposed upstream and downstream end portions. The upstream end portion includes a fluid receiving section and the downstream end portion includes a fluid discharge section and defines a spray opening for emitting an atomized spray therefrom. The nozzle body defines a central bore which extends between the fluid receiving section and the fluid discharge section and delineates a central axis and delimits an interior locating surface for the orifice disc.

The orifice disc includes axially opposed upstream and downstream surfaces which define a peripheral surface therebetween. The peripheral surface is adapted and configured for slidable engagement with the interior locating surface of the nozzle body. The orifice disc further includes a spray orifice that extends between the opposed upstream and downstream surfaces. The downstream surface has a protuberance formed thereon for increasing the axial length of the spray orifice. It is envisioned that the spray orifice of the orifice disc further includes a tapered inlet formed in the upstream surface of the orifice disc so as to centrally direct fluid provided thereto. Preferably, the protuberance has a chamfered downstream edge which facilitates the insertion of the protuberance into the opening of the nozzle body.

The present disclosure is also directed to a spray nozzle which includes a nozzle body, a swirl element, an orifice disc and a locking mechanism. The nozzle body, swirl element and orifice disc being similar to those described for previous embodiment. The locking mechanism is disposed within the central bore of the nozzle body and is positioned upstream of the swirl element. The locking mechanism is dimensioned and configured for engagement with at least one groove formed in the central bore of the nozzle body. In one embodiment, the locking mechanism is provided in the form of a plate member. Alternatively, the locking mechanism includes protrusions formed on the upstream portion of the swirl element peripheral surface which are adapted and configured for engagement with the at least one groove. Also, the locking mechanism can be formed as an independent structural element or can be integral with the swirl element.

In an alternative embodiment, the locking mechanism includes a retainer element disposed within the central bore of the nozzle body which is positioned upstream of the swirl element. The retainer element includes a retainer disc and a seal member. The retainer disc has opposed upstream and downstream planar surfaces and a peripheral surface extending therebetween. A recess is formed in the peripheral surface and the seal member is disposed therein. When the retainer element is disposed within the central bore, the seal member engages with the at least one groove formed in the central bore. It is envisioned that the retainer disc includes flow apertures which extend between the opposed upstream and downstream planar surfaces to provide fluid communicated between the fluid receiving portion of the nozzle body and the upstream portion of the swirl element peripheral surface.

Preferably, the locking mechanism includes a tool engaging portion for facilitating the rotational engagement of the locking mechanism with the recesses formed in the central bore, where such rotational movement is required to remove the locking mechanism.

Those skilled in the art will readily appreciate that the subject invention facilitates the replacement of worn internal nozzle components and the reassembling of the nozzle, whilst ensuring the retention of said internal components during the reinstallation process of the assembled nozzle. These and other unique features of the spray nozzle disclosed herein will become more readily apparent from the following description, the accompanying drawings and the appended claims.

These and other features of the subject invention will become more readily apparent to those having ordinary skill in the art from the following detailed description of preferred embodiments.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

In the description which follows, as is common in the art to which the subject invention appertains, “upstream side” shall refer to the end of the component which faces the inlet side of the nozzle, while “downstream side” shall refer to the side that faces the discharge orifice of the nozzle. InFIGS. 1,2and6athe upstream and downstream ends of the nozzle are identified by reference characters U and D respectively.

Referring now to the drawings wherein like reference numerals identify similar elements of the subject invention, there is illustrated inFIG. 1a prior art spray nozzle designated generally by reference numeral100. As shown herein, spray nozzle100, includes a nozzle body10, an orifice disc12, a swirl chamber block member14, and a retainer member18for retaining and positioning the orifice disc12and chamber member14in the nozzle body10.

The nozzle body10is constructed from stainless steel and includes an opening20at the downstream end for the emission of spray from the orifice disc12and an elongated passage22for receiving the various components of the nozzle. A suitable gasket24is preferably disposed between shoulder25adjacent to opening20and the orifice disc12. The gasket24prevents fluid from leaking around the periphery of orifice disc12and between the disc12and shoulder25.

The swirl chamber member14has a spiral swirl chamber16formed therein with a generally tangential inlet17. The swirl chamber member14is positioned adjacent to the orifice disc12such that the downstream side of the swirl chamber16communicates with a spray orifice13formed in the orifice disc12, and the upstream side communicates with retainer member18. Retainer member18is preferably cruciform in shape and is engaged with the nozzle body10by way of threads26to maintain the gasket24, orifice plate12, and swirl chamber block member14position, as shown inFIG. 1. The exterior of the nozzle body10preferably includes threads28for receiving a fluid delivery conduit (not shown) which delivers the fluid to be sprayed to the nozzle body10. The flow path of the fluid through the nozzle100is shown by the arrows inFIG. 1, flowing through the cruciform retainer member18to the outside of the swirl chamber member14, where the fluid passes through the tangential inlet17of the swirl chamber16, swirls about the spiral swirl chamber, and exits through the orifice13in the plate12in the form of a finely atomized spray.

As discussed previously, the flow passages in swirl chamber block member14and orifice disc16wear due to the flow velocity of the fluid and therefore, must be frequently replaced. However, due to the configuration of spray nozzle100, reassembling the nozzle is difficult. In order to engage the nozzle body10, including the orifice disc12and the associated O-ring24, with the adapter18, either the adapter18or the nozzle body10must be inverted. The inversion of the adapter18or the nozzle body10causes the internal components to unseat, become misaligned and often fall out.

Referring now toFIG. 2, there is illustrated a spray nozzle constructed in accordance with a preferred embodiment of the subject invention and designated generally by reference numeral200. Spray nozzle200primarily includes a nozzle body210, an orifice disc212, a swirl unit214, and an adapter member218. Nozzle body210has a central bore222formed therein for receiving the orifice disc212and the swirl unit214. Additionally, a discharge portion220is provided in downstream nozzle end221and defines a spray opening223for emitting an atomized spray therefrom. The central bore222extends from upstream nozzle end227to the discharge portion220and defines a central axis240for nozzle200and interior locating surface242.

The orifice disc212is disposed within the central bore222of the nozzle body210and is positioned adjacent to the discharge portion220. An O-ring gasket211is provided between the orifice disc212and discharge portion220of the nozzle body210. The gasket211provides a seal which prevents fluid from leaking around the periphery of the orifice disc212and between the orifice disc212and discharge portion220into spray opening223.

As shown inFIG. 5, the orifice disc212has axially opposed first and second end surfaces,244and246respectively, and a spray orifice213extending therebetween. A peripheral surface248extends between end surfaces244and246and slidably engages with the interior locating surface242of the nozzle body210. The orifice disc212also includes a protuberance274associated with first end surface244. The protuberance274increases the overall thickness of the orifice disc212so as to increase the length of the spray orifice213. This additional thickness allows for the feed inlet215to be chamfered, thus permitting the centralizing of the spray flow while maintaining the straight spray orifice length on the outlet side217of the orifice disc. Preferably, orifice disc212is constructed from tungsten carbide, chrome carbide or a ceramic material.

With continued reference toFIG. 2, swirl unit214is also disposed within the central bore222of the nozzle body210and is positioned adjacent to orifice disc212. Preferably, swirl unit214is manufactured from tungsten carbide, hardened stainless steel or a ceramic material. The swirl unit214has a peripheral surface252and a swirl chamber254formed therein (FIG. 5). The peripheral surface252has a lower portion256and upper portion258. The lower portion258of the peripheral surface252slidably engages with nozzle body locating surface242. In contrast to nozzle100, the axial alignment of the orifice disc212and the swirl chamber214of nozzle200are controlled by a single locating surface242. The use of a single locating surface for the axial alignment of the swirl unit214and the orifice disc212, ensures that the desired offset of the spray orifice223with respect to the swirl origin is achieved. Interior swirl chamber254of the swirl unit214includes an approximately curvilinear surface which defines a swirl origin (not shown) and has a fluid receiving portion262in fluid communication with flow port264and a fluid discharge portion266in fluid communication with the spray orifice213of the orifice disc212.

In the assembled configuration, the adapter member218is threadably engaged with the second end227of the nozzle body210so as to contain the orifice disc212and swirl unit214within the bore222of the nozzle body210. An adapter O-ring gasket268is disposed between the adapter member218and the nozzle body210for preventing fluid leakage from the assembled nozzle200.

Liquid feed flows through nozzle200as indicated by the flow arrows. A feed supply conduit (not shown) is engaged with adapter218at surface241. The feed passes through the adapter218and enters flow port264defined by the space between swirl unit214and nozzle body210. As shown inFIG. 3, swirl unit214has a trapezoidal recess278formed in peripheral surface252for increasing the flow area between the swirl unit and the nozzle body210. Those skilled in the art will readily appreciate that the depth, quantity and configuration of recess278can be selectively adjusted based on the desired nozzle flow characteristics. If flow port264is capable of providing a sufficient liquid feed flow rate based on the intended application, recess278may not be required. Alternatively, a recess could be formed in nozzle body210in stead of swirl unit214.

The liquid feed enters the swirl chamber254of the swirl unit214through fluid receiving portion262and a spiral motion is imparted thereon as known to those skilled in the art. The feed then exits the swirl chamber254through discharge portion266and is atomized by spray orifice213. Atomized feed exits spray orifice213and spray opening223of the nozzle body210.

With continuing reference toFIG. 2, spray nozzle200further includes a locking plate230which is engaged with corresponding recesses231aand231bwhich are formed in nozzle body210. As discussed previously, reassembling a spray nozzle is complicated by the inability to properly maintain the alignment and positioning of the internal components when the nozzle body is being engaged with the adapter. Locking plate230provides a mechanism for positively securing the orifice disc212and swirl unit214in place and compressing the orifice O-ring gasket211prior to threadably engaging the nozzle body210with the adapter218. The locking plate230is preferably manufactured from a suitable wear resistant material, such as for example tungsten carbide or a ceramic material.

After the gasket211, orifice disc212and swirl unit214are positioned within the bore222, locking plate230is installed through access segment cuts270aand270bprovided in the nozzle body using a suitable fixing tool. When face271of locking plate230contacts the recesses231aand231bof the nozzle body210, locking plate230is rotated clockwise into the recesses until the fully locked position is reached. The assembly, which includes the nozzle body210, swirl unit214, orifice O-ring gasket211and orifice disc212is thereupon a fixed unit and is ready for engagement with the adapter.

The locking plate230also includes a tool receiving portion282for facilitating the rotational engagement of the locking plate230with the nozzle body210. The locking plate, in addition to securing the internal components within the nozzle body, provides a mechanism for ensuring that O-ring gasket211is properly compressed and a fluid tight seal is established between the orifice disc212and the discharge portion220of the nozzle body210. This is achieved by selectively positioning the recesses231aand231bwith respect to the second end227of the nozzle body210such that the desired compression is obtained. It should be noted that recesses231aand231bare formed such that they are positioned in a plane extending through central axis240at a right angle. Alternatively, the recesses could be formed in a plane which intersects the central axis240at an acute angle, and therefore, the rotational manipulation of locking plate230increases or decreases the compression of O-ring gasket211.

Referring now toFIG. 6a, there is illustrated a spray nozzle constructed in accordance with an alternate embodiment of the subject invention and designated by reference numeral300. Similar to spray nozzle200, spray nozzle300includes a nozzle body310, an orifice disc312, a swirl unit314, and an adapter member318. However, in contrast to spray nozzle200, spray nozzle300further includes a retainer element330.

Retainer element330is disposed within the central bore322of nozzle body310and is positioned upstream of swirl element314. The retainer element330includes a retainer disc332and a seal member342. As shown inFIGS. 7a-7c, the retainer disc332has opposed upstream and downstream planar surfaces,334and336respectively, and a peripheral surface338extending therebetween. A groove339is formed in peripheral surface338for receiving seal member342. As shown inFIG. 6a, seal member342is engaged within a corresponding recess360formed in the central bore322of the nozzle body310so as to secure the retainer element330, swirl element314, and orifice disc312within the central bore322.FIG. 6billustrates the configuration of the recess360formed in central bore322which has a radius “R”.

Retainer element330functions similar to that of locking plate230in that it facilitates the reassembling of nozzle300. Retainer element330provides a mechanism for positively securing the orifice disc312and swirl unit314in place and compressing the orifice O-ring gasket311prior to threadably engaging the nozzle body310with the adapter318. After the O-ring gasket311, orifice disc312and swirl element314are positioned with the central bore322, the retainer element330is inserted into the central bore322until the seal member342engages with recess360. Recess360is positioned such that proper compression is applied to O-ring gasket311.

With continued reference toFIG. 6a, orifice disc312is similar in configuration to orifice disc212illustrated inFIG. 5. However, the protuberance374associated with the downstream surface344of orifice disc312has a chamfered downstream edge375. Chamfered edge375facilitates the insertion of the protuberance374into the spray opening323of the nozzle body310and the alignment of the orifice disc312.

In contrast to swirl element214ofFIG. 2, swirl element314includes a tapered neck portion359associated with an upstream end358thereof. The tapered neck portion359facilitates the flow of fluid through nozzle300by providing a smoother transition for the flow from the nozzle body inlet region352to the swirl inlet (not shown). In addition, flow apertures337a-337d(FIG. 7c) are provided in retainer disc332and further facilitate fluid communication through valve300. Those skilled in the art would readily appreciate that the quantity, shape and size of the flow apertures can vary depending on the desired flow characteristics for spray nozzle300. The tapered neck portion359of the swirl element314and the flow apertures337a-337dprevent blockages from being formed within nozzle300and reduce the pressure loss across the nozzle.

Those skilled in the art will readily appreciate that various materials can be used for the construction of the spray nozzle components disclosed herein. Spray nozzle wear largely depends upon its corrosion and erosion resistance. Corrosion occurs when the liquid feed and nozzle component material are chemically incompatible. Erosion results from the liquid feed with its abrasive solids passing through the flow passages at high velocities and physically removing component material. Corrosion problems can often be avoided or at least greatly reduced by determining the chemical characteristics of the liquid feed. Various materials can then be used based upon their ability to resists chemical and physical attack. Material possibilities are too numerous to list, but the materials disclosed herein are intended for illustrative purposes only and are not intended to limit the scope of the disclosure.

While the invention has been described with respect to preferred embodiments, those skilled in the art will readily appreciate that various changes and/or modifications can be made to the invention with departing from the spirit or scope of the invention as defined by the appended claims.