Patent Application
20240198487
Not Applicable
Not Applicable
Not Applicable
The present invention relates to abrasive media blasting and more particularly relates to systems capable of both wet and dry abrasive media blasting. (B24C)
Traditional dry abrasive media blasting uses an abrasive media such as sand and compressed air to propel the abrasive media at high velocity at a desired surface.
Typically the dry media is housed in a cylindrical blast pot with a lower conical end. The abrasive media flows downwardly under gravity out of an orifice in the bottom of the pot. The amount of abrasive flow is controlled with a metering valve at the bottom of the blast pot. The abrasive media is inserted into a stream of compressed air creating a mixture of compressed air with entrained abrasive media. These type of systems typically are limited to an abrasive media size of no smaller than 40-80 mesh beyond which clumping and non-uniform flow of abrasive media is observed in the blast pot which results in an uncontrollable flow of abrasive media.
Traditional wet abrasive media blasting uses an abrasive media such as sand which is mixed with water to create a slurry which is loaded into a similar blast pot as with the dry blasting described above. The blast pot is bled of all air since entrapped compressible air in the blast pot causes well known uncontrollable and unwanted pressure fluctuations that effect the consistency and safety of the blasting operation. This problem is described in U.S. Pat. No. 8,986,074 titled Fluid Control Circuit for Wet Abrasive Blasting by inventor Keith Eliason. The water abrasive slurry is inserted into a stream of compressed air creating a mixture of compressed air with entrained abrasive media and water. The slurry expended in the blast pot is replaced with water which is pumped into the blast pot under a controlled pressure which in turn controls the amount of slurry inserted into the air stream.
A Wet and Dry Abrasive Media Blasting System is described in U.S. Pat. No. 11,484,988 titled Dry Wet Blast Media Blasting System by inventor Phuong Taylor Nguyen. The system described by Nguyen is a dry blast system wherein water is injected downstream but in close proximity to the abrasive/air mixing device. In particular See
The present wet and dry abrasive media blasting system simplifies the equipment required and improves the performance of the blasting process for both wet abrasive media blasting and dry abrasive media blasting in a single multi-purpose blasting unit.
The present concept is a wet and dry abrasive media blasting system which includes a compressed air supply providing a supply of blast air and pot air, wherein the blast air is communicated along a blast air supply line and pot air is communicated along a pot air supply line; a blast pot is configured to receive abrasive media and pot air and release abrasive media at a discharge into a media conduit which communicates the abrasive media to a mixing device; an air pressure amplifier disposed on the pot air supply line, is adapted to selectively increase the air pressure of the pot air creating a pot air head over-pressure within the blast pot, wherein the pressure of the pot air head, minus the pressure of the blast air, is the over-pressure which is positive; wherein the blast air and the abrasive media are mixed together in the mixing device to form a blast air media mixture which is communicated to a nozzle and discharged from the nozzle as a blast spray.
The wet and dry abrasive media blasting system further comprises a metering valve, disposed on the media conduit, downstream of the discharge, and up stream of the mixing device, the metering valve selectively controls the flow of abrasive media and therefor the amount of abrasive media communicated to the mixing device.
The wet and dry abrasive media blasting system wherein the metering valve is disposed at an elevation above the discharge.
The wet and dry abrasive media blasting system wherein the metering valve is disposed at an elevation greater than ten inches above the discharge.
The wet and dry abrasive media blasting system further comprising a pressure regulator disposed on the blast air supply line to selectively control the air pressure of the blast air thereby ensuring a consistent over-pressure.
The wet and dry abrasive media blasting system further comprising a pressure regulator, disposed upstream of the air pressure amplifier on the pot air supply line, to selectively control the air pressure of the pot air introduced into the air pressure amplifier.
The wet and dry abrasive media blasting system wherein the over-pressure is between 1% and 200% of the blast air pressure.
The wet and dry abrasive media blasting system wherein the over-pressure is between 5% and 100% of the blast air pressure.
The wet and dry abrasive media blasting system wherein the over-pressure is between 10% and 50% of the blast air pressure.
The wet and dry abrasive media blasting system wherein the pressure amplifier is an air driven air pressure amplifier.
The wet and dry abrasive media blasting system wherein the abrasive media is selected from the following, a wet media, and a dry media.
The wet and dry abrasive media blasting system wherein the mixing device is a T connection.
The wet and dry abrasive media blasting system wherein the compressed air supply is a single air compressor supplying compressed air to the blast air supply line and to the pot air supply line.
The wet and dry abrasive media blasting system wherein the compressed air supply includes two air compressors, one for supplying compressed air to the blast air supply line and a second for supplying compressed air to the pot air supply line.
A wet and dry abrasive media blasting system of the type including;
The accompanying drawings, which are included to provide a further understanding of the invention are incorporated in and constitute a part of this specification, illustrate an embodiment of the invention and together with the description serve to explain the principles of the invention. They are meant to be exemplary illustrations provided to enable persons skilled in the art to practice the disclosure and are not intended to limit the scope of the appended claims.
The following detailed description is merely exemplary in nature and is not intended to limit the described embodiments of the application and uses of the described embodiments. As used herein, the word “exemplary” or “illustrative” means “serving as an example, instance, or illustration.” Any implementation described herein as “exemplary” or “illustrative” is not necessarily to be construed as preferred or advantageous over other implementations. All of the implementations described below are exemplary implementations provided to enable persons skilled in the art to practice the disclosure and are not intended to limit the scope of the appended claims.
Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, brief summary or the following detailed description.
The reader will note that “abrasive media” 323 also referred to as simply “media” refers to an abrasive substance which encompasses both wet media 324 and dry media 325. Dry media 325 may be for example be sand, corundum, garnet, alumina or any other known abrasive granular materials. Wet media 324 may for example be a slurry of water or another liquid, and any of the known available abrasive dry media materials.
The reader will also note that the term over-pressure herein is defined as the pressure of the pot air head 322, minus the pressure of the blast air 304. For satisfactory operation the over-pressure is positive. Pot air head 322 is pot air within the upper portion 321 or head portion of the blast pot 326.
This type of system typically is limited to an abrasive media size of no smaller than 40-80 mesh. The dry abrasive blast media 116 must flow downwardly in blast pot 114 in a predictable manner to provide a controllable system. It is observed that using dry abrasive blast media 116 finer than 40-80 mesh produces clumping and non-uniform flow of abrasive media in the blast pot 114 which results in an uncontrollable flow of abrasive media.
Compressed air 230 flows through air conduit 231 which includes an on-off air valve 232 and a check valve 234 to prevent flow of slurry further into air conduit 231. Compressed air 230 mixes with abrasive slurry 214 at mixing device 228 where water, abrasive media, and compressed air mix together and flow through blast hose 236 an nozzle 238 where the mixture is discharged as blast spray 240.
The blast pot 215 is bled of all air since entrapped compressible air in blast pot 215 causes well known uncontrollable and unwanted pressure fluctuations that effect the consistency and safety of the blasting operation. The water abrasive slurry 214 is inserted into air stream 237 creating a mixture of compressed air with entrained abrasive media and water. The abrasive slurry 214 expended in blast pot 215 is replaced with pressure regulated water 206 which is pumped into the blast pot 215 under a controlled pressure which in turn controls the amount of abrasive slurry 214 inserted into air stream 237.
In practice pressure regulated water 206 is typically regulated to be higher than the pressure of compressed air 230 flowing in air stream 237. This higher pressure moves abrasive slurry 214 freely out of blast pot 114 and ensures entrainment of abrasive slurry 214 into the air stream 237 at the mixing device 228.
Wet and dry abrasive media blasting system 300 includes the following major components namely incoming compressed air supply 302, which bifurcates into two branches the first along pot air supply line 306 for supplying pot air 308 and second along blast air supply line 305 for supplying blast air 304. Blast pot 326 is an air tight pressure vessel which is capable of containing compressed air, water, abrasive media including dry abrasive blast media and wet abrasive blast media.
Pot air 308 flows through air filter 310, a pressure regulator 312 and through an air pressure amplifier 314 before entering blast pot 326. Preferably a pressure gauge 316 indicates the inlet air pressure into blast pot 326. In practice pot air 308 forms a pot air head 322 above abrasive media 323. The pressure of pot air head 322 is higher than blast air 304 pressure in order to ensure smooth delivery of the abrasive media 323 out of discharge 330. The air pressure amplifier 314 disposed on the pot air supply line 306, is adapted to selectively increase the air pressure of the pot air 308 creating a pot air head 322 over-pressure within blast pot 326. Over-pressure is the pressure of pot air head 322, minus the pressure of the blast air 304 and is always positive. The over-pressure may be from 1 to 200% of the blast air pressure, more preferably from 5% to 100% of blast air pressure and more preferably from 10% to 50% of blast air pressure.
Pot air head 322 is usually a distinct phase above the abrasive media 323. Pot air head 322 is mainly compressed pot air 308 regardless of the type of abrasive media 323 such as wet media 324 or dry media 325. This creates an extremely flexible system capable of using wet or dry abrasive media with surprisingly improved abrasive flow control.
Improved control of the flow of the abrasive media, also termed flow control, is the result of using an air pressure amplifier 314 which creates a pot air head 322 with a controllable over-pressure. Further improvements in flow control are observed with the additional use of metering valve 336 and the optimized positioning of the metering valve 336. Further improvements in flow control are observed by using a blast air 304 pressure regulator 338 which further ensures a consistent over-pressure.
Many types of air pressure amplifiers are available and could work however air pressure amplifier 314 is preferably powered by the air it amplifies and can be selected to provide a wide range of pressures. This type of air pressure amplifier 314 is referred to as an air driven air pressure amplifier.
Blast pot 326 includes a media fill opening 318 and a fill valve 320 to load the blast pot with the selected abrasive media 323 which in the case of wet blasting usually includes abrasive and water namely wet media 324, and in the case of dry blasting includes only dry abrasive media namely dry media 325. The abrasive media 323 flows down the conical section 328 of blast pot 326 and out though discharge 330 and into media conduit 332. A metering valve 336 can be used to increase the control of the flow of the abrasive. Preferably the metering valve 336 includes an on/off function for completely cutting off the flow through the media conduit 332.
Blast air 304 flows through a pressure regulator 338 which can be used to selectively control the blast air pressure. Pressure regulator 338 helps maintain a uniform and consistent over-pressure. Preferably pressure regulator 338 includes an on/off function to completely shut off the flow of blast air 304. Wet media 324 or dry media 325 mixes with blast air 304 at mixing device 340 which forms blast air/media mixture 343 which then flows through blast line 342, and out through nozzle 344 as a blast spray 346. Mixing device 340 works well as a simple T connection, but it may also be a Y connection or it may be any other mixing device known in the industry.
The reader will note that when using the system for dry abrasive media blasting or for wet abrasive media blasting the upper portion 321 of blast pot 326 contains primarily pot air 308 which forms a pot air head 322. Operating the system in a wet mode is with pot air head 322 over wet media 324 which preferably is a mixture of water and an abrasive media also referred to as an abrasive slurry. Operating the system in a dry mode is with pot air head 322 over dry media 325 which preferably is a dry abrasive blast media.
In regard to operating the wet and dry abrasive media blasting system 300 in the wet mode the air pressure amplifier 314 ensures that pot air head 322 pressure is always higher than blast air 304 pressure. This is referred to as air over-pressure which is not found in prior art wet systems. Prior art wet systems use water pressure only in the blast pot and go to lengths to eliminate any air in the blast pot 326. In the current system the amount of air over-pressure also allows one to control the rate at which wet media 324 is discharged from blast pot 326. Additionally wet and dry abrasive media blasting system 300 includes a abrasive media metering valve 336 which also helps control pressure fluctuations within blast pot 326 and provide enhanced control of the flow rate of wet media 324 to mixing device 340. The inventor has surprisingly found that the use of an air pressure amplifier 314 together with an abrasive media metering valve 336 results in a stable and controllable delivery of wet media 324 to the mixing device 340 which provides a stable, controllable and uniform blast spray 346.
In regard to operating the wet and dry abrasive media blasting system 300 in the dry mode the air pressure amplifier 314 ensures that pot air pressure is always higher than blast air pressure. This is referred to as air over-pressure which is not a feature in prior art dry blasting systems. Prior art dry blasting systems rely on gravity feed to move the dry blast media downwardly toward discharge 330. In gravity fed dry systems abrasives finer than 40 to 80 mesh tend to clump and clog within blast pot 326 and media conduit 332 which limits the use of such systems. In the presently described dry mode, the air over-pressure allows one to control the flow of dry abrasive media 325 through the blast pot 326 and media conduit 332. Metering valve 336 provides additional control such that a user can more easily obtain stable and uniform flow of dry media 325 to mixing device 340 and ultimately of blast spray 346. The metering valve 336 is disposed on the media conduit 332 downstream of the discharge 330 and up stream of the mixing device 340. In the present system much finer abrasives (up to 800 mesh) can be used without control issues.
In practice it has been determined surprisingly that placing the metering valve 336 at an elevation above discharge 330 results in even better control over the flow of abrasive media 323 through media conduit 332 and ultimately of control of the blast spray 346. Metering valve 336 is depicted at an elevation above discharge in
