Dry wet blast media blasting system
11679473 · 2023-06-20
Assignee
Inventors
Cpc classification
B24C5/02
PERFORMING OPERATIONS; TRANSPORTING
International classification
Abstract
A wet media blasting system with a water injection system that provides more uniform distribution of the water, air and media components for achieving a more efficient mixture while minimizing the amount of water required to contain and minimize or eliminate airborne particulate matter such as dust produced during the blasting operation. The system supports dry blasting, wet blasting, and water wash down modes and air drying modes. When blasting, by more thoroughly mixing the water into the abrasive/water mix, the amount of water required is reduced. The abrasive feed is placed and shaped to optimize spray coverage and minimize abrasive flow into injection space thus mitigating water nozzle clogs. The water injectors are downstream of the air/abrasive mixing station.
Claims
1. An abrasive media blast system of the type including a source of pressurized air, abrasive media and water in a wet abrasive mixture which can be released through a blast nozzle, the system comprising: a. A compressor for generating a stream of pressurized air; b. A source of abrasive adapted to be released into the pressurized air for generating an air/abrasive stream; c. An injector downstream; d. A source of water under pressure introduced into the injector and released from the injector into the air/abrasive mixture for creating an abrasive/water stream; and e. A blast nozzle in communication with the abrasive/water stream for receiving the abrasive/water stream and delivering it to a work surface, wherein in during operation the system is operable as follows: a. a first mode wherein the media delivery system, air flow and the water flow are both activated to provide a wet abrasive mixture for wet blasting; b. a second mode wherein only the media delivery system and air flow are activated to provide a dry abrasive delivery for dry blasting; c. a third mode wherein only the air flow is activated to provide a drying system; d. a fourth mode wherein only the water flow is activated to provide a water rinse.
2. The blast system of claim 1, further including a valve system for selectively disabling the source of water such that the mixture of pressurized air and abrasive media is delivered to the nozzle in a dry mix for dry blasting the work surface.
3. The blast system of claim 1, including a valve system for selectively disabling the source of abrasive media such that the pressurized water and air is delivered to the nozzle as pressurized water source for providing a water washdown directed to the work surface.
4. The blast system of claim 1, further including a differential pressure gage positioned between and in communication with the water pressure source and the air pressure source for monitoring and controlling water flow, for monitoring the water pressure relative to the air pressure.
5. The blast system of claim 4, wherein the differential pressure gage includes a visual indicator of the water flow rate.
6. The blast system of claim 4, wherein the differential pressure gage provides a visual indicator of the differential between the air pressure and the water pressure.
7. The blast system of claim 4, wherein the differential pressure gage assures that the water pressure is greater than the air pressure, wherein an abrasive media is introduced into the blast hose and into the flow of pressurized air downstream of the source of pressurized air and upstream of the source of water, the system comprising: a. a gate restrictor for directing and tightening the flow of abrasive media along a lower portion of the flow conduit; b. a water source downstream of the restrictor for providing a water shower for wetting the abrasive media as it flows through the flow conduit.
8. The wet dry blast system of claim 1, wherein water particles combine with dust particles of the abrasive in order to increase an overall mass of combined particles such that the combined particle is no longer light enough to stay airborne.
9. The blast system of claim 8, wherein the first mode defines an abrasive/water mix wherein air flow, media release and water flow are activated for wet blasting.
10. The blast system of claim 8, wherein the fourth mode defines a water rinsing system with water being dispersed from the nozzle at a lower controlled pressure mode, wherein only the water flow is activated to provide a water rinse.
11. A water injection system for a blast system, comprising: an elongated conduit having one end coupled to an air injector system and the other end coupled to a blast nozzle; the air injector system adapted for supplying pressurized air flow flowing from said one end toward and out the nozzle at said other end; a media delivery system for introducing media into the conduit and into the air flow downstream of said one end; and a water delivery system for introducing water into the air/media mix downstream of the media delivery system for generating a wet media mix for release at the nozzle for providing a wet blasting mix, wherein the media delivery system includes a restrictor for directing the injected media to a predefined area of the conduit to provide more clear space for the injected water.
12. The blast system of claim 11, wherein there is further comprised of a water inlet chamber which is positioned outside of the conduit and in communication therewith, water release nozzle in the chamber, whereby the water release nozzle is spaced from and does not come in direct contact with the interior of the conduit.
13. The blast system of claim 12, wherein the water inlet chamber has an outlet orifice on an oblique angle relative to the conduit with the water release end of the inlet chamber skewed toward the downstream flow of the conduit, minimizing backflow from the conduit flow path into the water release system.
14. The blast system of claim 11, wherein the interior cross-sectional area of the conduit has a larger interior diameter at the nozzle end and a smaller interior diameter at the air flow injection end, reducing the likelihood of gravity backflow.
15. The blast system of claim 14, wherein the different interior diameters are generated by step components.
16. The blast system of claim 14, wherein the different interior diameters are created by a gradual slope on the interior wall of the conduit.
17. The blast system of claim 11, wherein the interior diameter of the conduit at the release point of the water delivery system is larger than the interior diameter of the conduit at the air injector end to further reduce the likelihood of back flow of media into the water delivery system.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1)
(2)
(3)
(4)
(5)
DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS
(6) The subject invention is directed to a wet media blasting system with a unique water injection system that provides more uniform distribution of water air and abrasive for achieving better application of the mixture while minimizing the amount of water required to contain and minimize or eliminate airborne particulate such as dust produced the blasting operation.
(7) A differential pressure gage 26 is positioned between water pressure line 28 and blast air pressure line 30 to indicate, quantify, and control water flow. A metering valve 50 is used to provide adjustable and repeatable water flow control to control water flow by varying the effective flow rate for water. The water pump 34 (
(8) The differential pressure gage reading provides the operator with a visual indication of water volume flow rate. In addition, a water flow adjustment valve 31 is provided for permitting the operator to adjust the water pressure. The pressure differential indicator 26 and the water flow adjustment valve 29, in combination, provide the operator with the means to consistently, precisely, and repeatedly control the water flow rate. Manually variable water flow is important because each operator will adjust the water flow according to the abrasive type, abrasive size, abrasive flow rate, dust content, blast nozzle size, blast pressure, and other blast equipment operating parameters.
(9) An additional feature of the invention is the inclusion of a wash down mode. After wet blasting, the surface is usually left with residual abrasive and fine dust. This requires a rinse to wash the abrasive off the surface. The water flow rate for washdown is significantly higher than the water flow rate during blasting, which is usually for dust control. It may be desirable to include a second injector 57 to be employed only during wash down for increasing the pressure and water flow when more pressure and water volume is required than can be delivered by the single spray injector 56.
(10) Another additional feature is a blow off function using compressed air to blow dry and ready the blasted surface for finishing, such as painting. This feature basically allows two settings of air pressure. One is for blasting which is generally greater than 80 psig. The washdown and blow off could be the same as blast air pressure or lower pressures such as 40 psig. The operator can manually adjust the desired air pressure using the air pressure regulator.
(11) The system of the subject invention can be configured as a portable unit or as a stationary system (with a large blast pot for storing and delivering abrasive media to the system through a metering valve 50, as shown in the drawings). This maximizes adaptability to various operations. The portable unit is equipped with handles and wheels and can be rolled to locations where blast jobs are remotely performed. The stationary unit is designed to be installed in a permanent location and may be installed below an abrasive hopper 5 (or blast pot), removing the need to have an abrasive hopper 5 mounted on the unit and also increasing capacity. Single or multiple spray nozzles may be utilized as determined by the compressed air requirements for each application. The spray nozzle size and blast pressure determine the compressed air requirements. Air compressor size is also determined by each application. Single outlet and multiple outlet units are supported.
(12) The system is adapted to be connected to a blast hose (not shown) which is connected to the blast nozzle outlet 20 for delivering the wet abrasive mix to a workstation, i.e., a surface to be treated. A source of abrasive media is provided in storage unit 5 to be fed by gravity into a mixing chamber 23 in the metering valve 50. The pressurized air flows into and through the metering chamber picking up the released abrasive, exiting as an air/abrasive mix. The mix then flows into and through the water injection module 24 downstream of the mixing metering valve 50, where a source of pressurized water is injected into the air/media mix by the injector 56 (and optionally injector 57) upstream of the blast nozzle outlet 20, but downstream of the mixing metering valve.
(13) The system supports disabling the source of abrasive media such that the pressurized water and air are delivered to the nozzle as pressurized water source for providing a water washdown mode for the system. Also, the system supports a mode permitting the source of water and the source of abrasive media to be disabled, i.e., OFF, permitting the pressurized air flow to operate as a drying system or other blower functions. The water control valve 70 controls flow through the network and includes at least one differential pressure gage 26 positioned between and in communication with the water pressure source and the air pressure source for monitoring and controlling water flow, and for monitoring the pressure differential between water pressure and air pressure to assure that the water pressure is greater than the air pressure.
(14) Operational circuits for the system are shown in
(15) Turning specifically to
(16) In the alternative embodiment of
(17) The air/abrasive mix of media 13 is gravity fed from the abrasive storage container 5 and downstream into the injection chamber 91 and upstream of the water injection module 24. This design shares the abrasive flow restrictor 12 (
(18) Pressure of the water/air/media flow depends upon the air pressure at the dam and/or or gate restrictor 12. The metering valve 50 directs the flow to a lower portion of the conduit, tightening the flow of abrasive media along specified portion of the of water injection module 24. The inner walls of the conduit 91 define the water injection module 24 which includes restriction on media flow through a controlled path, with restrictions and management of the path of the mix as it passes through the water injection module 24.
(19) As shown, the air/abrasive mix enters the water injection module as the mix flows from the metering valve 50 to conduit port 97. The flow is restricted by the changes in internal diameter of the spraying chamber. A restrictor 12 is provided at the port 99 to limit the amount of media 13 that is released from the storage tank 5 and into the mixing chamber of metering valve 50. The flow diameter of the conduit is largest at the actual injection point 98 and the media tend to drop into a dip in the conduit floor at this point, which, along with the water spray from the nozzle(s), pushes the media up and out through the narrow opening in the blast flow port 100 of the module 24 and into the blast nozzle module 101.
(20) The wet dry blast system of the subject invention can be configured in any one of four separate modes as controlled by the control panel 10. All of the modes require pressurized air. Pressurized water is used in wet blast and washdown modes. The operating panel 10 (
(21) The water pressure differential gage 26 (see also
(22) A branch conduit 34A of water the delivery conduit 34 provides the differential gage 26 with a continual reading of the water pressure in the system.
(23) Operational circuits for the system are shown in
(24) In contrast, in
(25) Output from either water pump 34 (electric) or 45 (pneumatic) is delivered to the water flow adjustment valve 40. The water pump 34 (or 45 in the electric diagram,
(26) The system includes conduit segment 24 having one end coupled to an air injector system and the other end coupled to a blast nozzle. The air injector system is adapted for supplying pressurized air flow flowing from one end, through the metering valve 50 and toward and out the blast nozzle outlet 20 at the other end. The media delivery system is configured to introduce media into the conduit and into the air flowing through the metering valve 50 with the water delivery system adapted for introducing water into the air/media mix downstream of the media delivery system for generating a wet media mix for release at the blast nozzle for providing a wet blasting mix.
(27) Typically, and as described below, the metering valve 50 is part of the media delivery system and includes a restrictor 12 in the metering valve 22 for directing the injected media to a predefined area 59 (See
(28)
(29) The wet/dry system of the invention is adapted for providing a mixture of wet abrasive and compressed air to a blast nozzle connected at outlet 20. The abrasive blast stream through the blast nozzle is used for removing rust, paint, or other unwanted surface defects. After abrasive blasting, the same system is used to wash off and dry the treated surface before it is ready for new paint or coating. Pressurized air is provided by a typical air compressor (not shown) connected to the auto air valve 47, a gate valve 45, and a water source 27. The blast abrasive is loaded into the abrasive blaster storage tank for example the blast pot 5 which is loaded through dan through an abrasive inlet 51 at the top of the blast pot. The abrasive can be bag loaded, or loaded from a larger storage hopper.
(30) To begin blasting, the abrasive inlet 51 is closed and the blast pot 5 is filled with compressed air from a standard air compressor (not shown). The air pressure in the abrasive blast pot 5 is raised until it is equal to the air pressure in the blast hose where it connects to the metering valve 50. This allows the blast abrasive to flow downward by gravity. The abrasive flow is controlled by the single metering valve 50, for example, the TeraValve (offered by Axxiom Mfg., Fresno, Tex.) at the bottom of the blast pot 5. From the metering valve 50 the blast abrasive flows into the blast air stream and the air/abrasive mix flow into the water injection module 24 where it is injected with water downstream of the metering valve 50. In order for the system of operate properly, the water pressure must be higher than the air pressure to assure that the air and abrasive mix cannot back flow. The mixture of wet abrasive and air then flows through the blast nozzle module 24, and through a blast hose (not shown), through blast nozzle and onto a work surface.
(31) Blasting starts when a deadman lever is engaged. In the embodiments of
(32) Blasting starts when the deadman switch is engaged and the pump power source is turned on, which will electrically or pneumatically open the control valve 40. When the main control valve 40 is open, an air signal simultaneously opens the automatic air valve 47. Compressed air will pressurize the blast hose when the automatic air valve 47 is opened. At the same time, the metering valve 50 and water control valve 53 will open allowing abrasive to fall through and water to be injected (see injectors 56, 57) into the blast air stream. Note that injector 56 is used in all modes that require water flow. Injector 56, if used, is optional and is only opened when the water flow needs to be of greater pressure and flow for the specific wash down application. The water flow is increased or decreased by turning the knob 73 at the water control section of the control panel 10. Blast air pressure can be adjusted by dialing the air pressure regulator 49.
(33) Blasting stops when the deadman switch is disengaged. This shuts off air to the signal port of the control valve 40.
(34) The abrasive blaster pot 5 is depressurized by closing a typical air inlet ball valve 61 (shown right of “AIR FILTER”) and then opening a typical blowdown ball valve 53, connected to top right of abrasive blaster pot 5 to completely vent the compressed air.
(35) In order to blast objects that are fragile it is necessary to reduce the blast air pressure. The blast pressure regulator 27 is used to adjust the blast pressure while in “BLAST MODE”. The air/water differential blast pressure is shown by the differential pressure gage 26 and can be adjusted while blasting. To adjust the blast pressure, the control knob 73 (
(36) The wash down mode is controlled by differential pressure. Adjustment is generally made while blasting so the effects are visible. To adjust the wash down pressure, the control knob 73 pulled out to unlock the system components. When the desired pressure is reached as indicated at differential gage 26, the knob 73 can be pushed in to lock it and prevent accidental changes.
(37) The inlet pressure gage 29 shows the air pressure supplied by the air compressor. This gage makes it possible to easily troubleshoot an insufficient supply of pressurized air. If the pressure on the inlet pressure gage drops while blasting, then the air supply is insufficient for the nozzle size and blast pressure combination being used. This is especially critical on two outlet units. Fluctuations in the blast pressure will make it impossible to maintain consistent water differential pressure. There are three ways to correct the problem, 1) change to a larger air compressor, 2) change to a smaller nozzle or 3) reduce the blast pressure until no pressure drop is observed on the inlet pressure gage 29.
(38) The electric version of
(39) In the pneumatic version of
(40) In practice, it is recommended to start at five psi of differential and then fine-tune to achieve the desired results. This is a matter of choice depending on application, operator preference and other local factors, as will be well understood by those skilled in the art.
(41) The water on/off button controls valve 40 is used to change between wet blast and dry blast. Pull the button out (“ON” position) for wet blast and push the button in (“OFF position) for dry blast. When the water on/off palm button control valve is in the “OFF” position, it stops the air signal to the water shut-off valve preventing the water from turning on. The water control valve 53 is a normally closed valve that opens to inject water into the blast stream. The water control valve opens when it receives air to its signal port. This happens when the deadman lever is engaged, which opens the blast control valve sending an air signal to the water shut-off valve. When the deadman lever disengaged, the air signal from the blast control valve vents and the water shut-off valve closes to stop the flow of water.
(42) The water injection module 24 (
(43) As shown in
(44) The water spray chamber 77 (see
(45) The differential pressure gage 26 is positioned between water pressure and blast air pressure to visually indicate, quantify, and control water injection flow rate. The ability to have consistent, adjustable, and repeatable water flow control with a simple operation is a significant advantage over prior art wet abrasive airblast systems. In the exemplary embodiment, the differential pressure indicator 26 is positioned to measure the difference between the water pressure and blast air pressure to confirm that the water pressure is greater than the air pressure.
(46) Typically, each spray nozzle 56 and 57 have a fixed orifice, and the water flow rate is proportional to how much the water pressure is greater than the blast air pressure. This differential pressure gage reading provides the operator with a visual indication of volume flow rate. In addition, a water flow adjustment valve 53 is provided for permitting the operator to adjust the water flow area during blasting. The pressure differential gage 26 and the water adjustment valve 53, in combination, provide the operator with the means to consistently and repeatedly control the water flow rate. Manually variable water flow is an important benefit because each operator will adjust the water flow according to the abrasive type, abrasive size, abrasive flow rate, dust content, blast pressure, and surface to be blasted.
(47) While certain features and embodiments have been explained in detail herein, it should be understood that the invention encompasses all modifications and enhancements in accordance with the following claims.