SPRAY TIP DESIGN AND MANUFACTURE
A spray tip for a fluid applicator includes a stem configured to be inserted into the fluid applicator. The stem includes a stem pre-orifice portion and an insert receiving portion. The spray tip includes a pre-orifice insert having an inlet and an outlet. The pre-orifice insert is disposed within the insert receiving portion and disposed against a rearward shoulder of the stem.
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The present application is based on and claims the benefit of U.S. Provisional Patent Application Ser. No. 62/643,265, filed Mar. 15, 2018, the content of which is hereby incorporated by reference in its entirety.
BACKGROUNDSpray tips are typically used in a variety of applications to break up, or atomize, a liquid material for delivery in a desired spray pattern. Some exemplary applications include, but are not limited to, applying a coating material such as paint, to a substrate, an agricultural application such as applying a fertilizer, insecticide, or herbicide to plants.
While examples described herein are in the context of applying paint to a surface, it is understood that the concepts are not limited to these particular applications. As used herein, paint includes substances composed of coloring matter, or pigments, suspended in a liquid medium as well as substances that are free of coloring matter or pigment. Paint may also include preparatory coatings, such as primers, and can be opaque, transparent, or semi-transparent. Some particular examples include, but are not limited to, latex paint, oil-based paint, stain, lacquers, varnishes, inks, etc.
SUMMARYA spray tip for a fluid applicator includes a stem configured to be inserted into the fluid applicator. The stem includes a stem pre-orifice portion and an insert receiving portion. The spray tip includes a pre-orifice insert having an inlet and an outlet. The pre-orifice insert is disposed within the insert receiving portion and disposed against a rearward shoulder of the stem.
This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This summary is not intended to identify key features or essential features of the claimed subject matter, is not intended to describe each disclosed embodiment or every implementation of the claimed subject matter, and is not intended to be used as an aid in determining the scope of the claimed subject matter. Many other novel advantages, features, and relationships will become apparent as this description proceeds. The figures and the description that follow more particularly exemplify illustrative embodiments.
In a fluid spraying system, a pump receives and pressurizes a fluid, delivers the pressurized fluid to an applicator, which, in turn, applies the pressurized fluid to a surface using a spray tip having a geometry selected to emit a desired spray pattern (e.g., a round pattern, a flat pattern, or a fan pattern, etc.). The fluid may comprise any fluid applied to surfaces, including, but not limited to, for example, paint, primer, lacquers, foams, textured materials, plural components, adhesive components, etc. For the sake of illustration, and not by limitation, the example of a paint spraying system will be described in detail.
Spray tip 100 may be manufactured using current assembly processes for spray tips. Normally, pre-orifice inserts 106 and 108 are manufactured separately from stem 102, and then inserted into channel 104. Such machining often utilizes outside diameter (OD) grinding of pre-orifice inserts 106 and 108 (which generally comprise tungsten carbide) with tight press tolerances. The pre-orifice inserts 106 and 108 are then inserted into channel 104 of stem 102. This process can create a large amount of scrap. Additionally, after the OD grinding process, pre-orifice inserts 106 and 108 might not press into stem 102 straight—in which case the assembly is considered a failure (e.g., the inserts do not align properly and can affect a desired spray pattern).
It is desired for a spray tip assembly process that does not require an OD grind, and where the parts assembly utilizes a slip fit, with a filler metal in a brazing process used to fill any gap. In one example, the filler metal used is a silver brazing filler metal. However, other suitable brazing filler metals, and other suitable bonding agents, are also envisioned.
Assembly operation 250 proceeds at block 254 where channel 202 is formed through stem 200. Channel 202 can be formed in a variety of different ways as indicated by blocks 256-260. As indicated by block 256, channel 202 can be machined or drilled through stem 200. For example, stem 200 is first formed as a cylinder and channel 202 is then bored into the cylindrical body of stem 200. As indicated by block 258, channel 202 can be casted or molded at the same time as stem 200. For example, the cylindrical shape of stem 200 is formed by a casting process, however, a die is placed in the casting mold to create channel 202 in the stem forming casting process. As indicated by block 260, channel 202 can be formed in other ways as well.
Assembly operation 250 proceeds at block 262 where pre-orifice inserts 204 are inserted within the stem 200. Assembly operation 250 then proceeds to block 264 where the pre-orifice inserts 204 are secured within stem 200. For example, the inserts are press fit against block 206 and as fluid flows through the inserts they are further forced against block 206 and cannot be pushed through entirely through channel 202. In one example, pre-orifice inserts 204 are press fit into channel 202 and are held in by friction.
Assembly operation 340 proceeds at block 360 where a channel 302 is formed through the stem 300. Channel 302 is shown formed in
Assembly operation 340 proceeds at block 370 where internal geometry is formed in the stem. As shown in
Assembly operation 340 proceeds at block 380 where a pre-orifice retaining portion is formed (as shown in
Assembly operation 340 proceeds at block 390 where the pre-orifice insert is secured within the stem. Pre-orifice insert 308 can be secured within the stem in a variety of different ways as indicated by block 392-398. As indicated by block 392, the pre-orifice insert 308 can be secured by brazing pre-orifice insert 308 into stem 300. For example, a filler metal can be provided and brazed from the downstream direction of pre-orifice insert 308 and fill in a gap between pre-orifice insert 308 and stem 300, securing pre-orifice insert 308. As indicated by block 394, a bonding agent can be used to secure pre-orifice insert 308 in stem 300. For example, a glue, epoxy etc. can be used as a bonding agent to secure pre-orifice insert 308 into stem 300. As indicated by block 396, pre-orifice insert 308 can be secured in stem 300 by friction of (e.g., pre-orifice insert 308 tightly fits in pre-orifice insert receiving portion 306 such that it will not fall out under an applied fluid pressure flowing through channel 302). Pre-orifice insert 308 can be secured in other ways as well, as indicated by block 398. For example, a combination of one or more methods could be used. For instance, pre-orifice insert 308 may be secured using friction and a bonding agent.
As shown in
As shown in
As shown in
As shown in
As shown, pre-orifice insert 442 is disposed rearwardly against rear shoulder 447 such that fluid does not flow around pre-orifice insert 442 and/or in between pre-orifice insert 442 and stem 440. In some examples, the fastening material couples and/or bonds pre-orifice insert 442 to rear shoulder 447.
As shown in
Stem 450 includes a counter bore 458. Counter bore 458, as shown, includes a cylindrical shape. However, in other examples, counter bore 458 can include other geometries (e.g., frustums, steps, spheres, etc.). As shown, pre-orifice insert 452 is disposed rearwardly against rear shoulder 455 such that fluid does not flow around pre-orifice insert 452. As shown, the fastening material 457 couples and/or bonds pre-orifice insert 452 to rear shoulder 455.
Although the present invention has been described with reference to preferred examples, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.
Claims
1. A spray tip for a fluid applicator, the spray tip comprising:
- a stem configured to be inserted into the fluid applicator, the stem comprising a stem pre-orifice portion and an insert receiving portion;
- a pre-orifice insert comprising an inlet and an outlet; and
- wherein the pre-orifice insert is mounted within the insert receiving portion and disposed against a rearward shoulder of the stem.
2. The spray tip of claim 1, wherein the pre-orifice insert is coupled to the pre-orifice receiving portion by a filler metal.
3. The spray tip of claim 2, wherein an external surface of the pre-orifice insert is disposed in the range 0.0012″ to 0.01″ away from an internal surface of the insert receiving portion.
4. The spray tip of claim 1, wherein the pre-orifice insert is coupled to the rearward shoulder by a filler metal.
5. The spray tip of claim 4, wherein an external surface of the pre-orifice insert is disposed in the range 0.0012″ to 0.01″ away from a surface of the rearward shoulder.
6. The spray tip of claim 1, wherein the stem pre-orifice portion comprises a frustum surface that widens in a downstream direction.
7. The spray tip of claim 1, wherein the stem pre-orifice portion comprises a first cylindrical surface having a first diameter and a second cylindrical surface having a second diameter.
8. The spray tip of claim 7, wherein the stem pre-orifice portion comprises a third cylindrical surface having a third diameter.
9. The spray tip of claim 1, wherein the stem pre-orifice portion is machined into the stem.
10. The spray tip of claim 1, wherein the pre-orifice insert comprises a frustum surface that narrows in a downstream direction.
11. A method of manufacturing a spray tip for a fluid applicator, the method comprising:
- creating a channel through a stem of the spray tip, the channel having a downstream outlet and an upstream inlet; and
- inserting a pre-orifice insert into the channel through the downstream outlet; and
- securing the pre-orifice insert into the channel.
12. The method of claim 11, wherein securing the pre-orifice insert comprises brazing the pre-orifice insert into place.
13. The method of claim 11, wherein securing the pre-orifice insert comprises applying a bonding agent to the pre-orifice insert.
14. The method of claim 11, wherein creating the channel through the stem comprises:
- machining a first hole in the stem;
- machining a pre-orifice insert retaining portion; and
- machining a stem pre-orifice portion that is upstream from the pre-orifice insert retaining portion.
15. The method of claim 11, further comprising:
- grinding the pre-orifice insert to an insert diameter that is at least 0.001″ smaller than a channel diameter of the channel.
16. The method of claim 11, wherein inserting the pre-orifice insert comprises disposing the pre-orifice insert against a rear shoulder of the channel.
17. The method of claim 11, further comprising machining a counter bore from the upstream inlet side of the channel.
18. A paint spray tip comprising:
- a cylindrical stem configured to be inserted and rotated within a paint spray gun;
- a flag coupled to the cylindrical stem;
- a channel disposed through the stem, the channel having an upstream inlet and a downstream outlet; and
- wherein a fluid path in the channel is defined at least in part by a pre-orifice portion of the cylindrical stem having a plurality of geometric portions and a pre-orifice insert.
19. The paint spray tip of claim 18, wherein the cylindrical stem comprises stainless steel and the tip insert comprises tungsten carbide.
20. The paint spray tip of claim 18, wherein the pre-orifice insert is coupled to the cylindrical stem by a filler metal.
Type: Application
Filed: Mar 11, 2019
Publication Date: Sep 19, 2019
Applicant:
Inventors: Ross D. Rossner (Leander, TX), Eric R. Seckerson (Greenfield, MN)
Application Number: 16/297,885