U.S. patent application number 16/621539 was filed with the patent office on 2020-03-26 for abrasive blast system.
The applicant listed for this patent is Graco Minnesota Inc.. Invention is credited to Robert J. Lind, John W. Turner.
Application Number | 20200094377 16/621539 |
Document ID | / |
Family ID | 64660227 |
Filed Date | 2020-03-26 |
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United States Patent
Application |
20200094377 |
Kind Code |
A1 |
Turner; John W. ; et
al. |
March 26, 2020 |
ABRASIVE BLAST SYSTEM
Abstract
A vapor abrasive blast system includes a compressor for
generating compressed air, a water pump for pumping a water stream
to a pressure vessel to pressurize the pressure vessel. A control
valve is disposed upstream of the pressure vessel and is configured
to control the flow of water from the water pump to the pressure
vessel to thereby control the flow of blast slurry downstream out
of the pressure vessel.
Inventors: |
Turner; John W.; (Coon
Rapids, MN) ; Lind; Robert J.; (Robbinsdale,
MN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Graco Minnesota Inc. |
Minneapolis |
MN |
US |
|
|
Family ID: |
64660227 |
Appl. No.: |
16/621539 |
Filed: |
June 14, 2018 |
PCT Filed: |
June 14, 2018 |
PCT NO: |
PCT/US2018/037578 |
371 Date: |
December 11, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62519235 |
Jun 14, 2017 |
|
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|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B24C 7/0084 20130101;
B24C 7/0038 20130101; B24C 7/0015 20130101; B24C 7/00 20130101 |
International
Class: |
B24C 7/00 20060101
B24C007/00 |
Claims
1. An abrasive blast system comprising: a water pump configured to
pump a flow of water from a water source to a pressure pot through
a water line; an air supply line extending from an air source; a
media line extending from the pressure pot to the air supply line;
a blast line extending downstream from a junction of the media line
and the air supply line to a nozzle; a control valve configured to
shift between an open state and a closed state to control the flow
of water to the pressure pot and thereby control the flow of blast
slurry from the pressure pot to the media line; and a blast control
switch controllable between an activated state and a deactivated
state and configured to actuate the control valve between the open
state and the closed state.
2. The abrasive blast system of claim 1, wherein the media line is
connected to the pressure pot at a first location and the media
line is connected to the junction at a second location, and wherein
the second location is disposed at higher elevation than a maximum
water level in the pressure pot.
3. The abrasive blast system of claim 1, wherein the control valve
is disposed on a portion of the water line between the water pump
and the pressure pot.
4. The abrasive blast system of claim 1, wherein the control valve
is configured to control activation of the water pump to thereby
control the flow of water to the pressure pot.
5. The abrasive blast system of claim 4, further comprising: a
system line extending from the air supply line to the water pump,
the system line configured to provide compressed air from the air
supply line to the water pump to power the water pump; wherein the
control valve is a valve disposed on the system line between the
air supply line and the water pump, the control valve configured to
control the flow of compressed air to the pump.
6. The abrasive blast system of claim 4, wherein the control valve
is configured to mechanically interact with the water pump to
prevent the water pump from pumping the flow of water when the
control valve is in the closed state.
7. The abrasive blast system of claim 1, further comprising: a
blast air controller configured to control a blast air flow through
the air supply line; wherein the blast control switch is configured
to actuate the blast air controller between an open controller
state and a closed controller state.
8. The abrasive blast system of claim 7, further comprising: a
system valve disposed on a system line branching from the air
supply line; a blast control line extending from the system valve
to the blast air controller; a pressurizing control line extending
from the system valve to the control valve; wherein the system
valve is configured to direct the system air flow to the blast
control line based on the blast control switch being in the
activated state and to direct the system air flow to the
pressurizing control line based on the blast control switch being
in the deactivated state.
9. The abrasive blast system of claim 8, further comprising: a
first pneumatic control line extending from the air supply line to
the blast control switch; a second pneumatic control line extending
from the blast control switch to the system valve; wherein the
blast control switch fluidly connects the first pneumatic control
line to the second pneumatic control line when in the activated
state such that compressed air from the air supply line can flow to
and actuate the system valve.
10. The abrasive blast system of claim 8, wherein the blast air
controller is normally-closed such that the system air flow
actuates the blast air controller to the open controller state, and
the control valve is normally-open such that the system air flow
actuates the control valve to the closed state.
11. The abrasive blast system of claim 1, further comprising:
control logic configured to implement a delay between the control
valve shifting between the open state and the closed state and the
blast air controller shifting between the open controller state and
the closed controller state; wherein the control logic causes the
blast air controller to shift to the open controller state before
the control valve shifts to the open state; and wherein the control
logic causes the blast air controller to shift to the closed
controller state after the control valve shifts to the closed
state.
12. The abrasive blast system of claim 1, wherein there is no valve
disposed downstream of the pressure pot to control the flow of
blast slurry through any one of the media line, the blast line, and
the nozzle during blasting.
13. A method comprising: generating a compressed air flow and
directing the compressed air flow to an air supply line extending
to a junction with a media line, the media line extending from a
pressure pot and being configured to convey a blast slurry flow to
the junction from the pressure pot; pumping, with a water pump, a
pressurizing water flow to the pressure pot through a water line
extending between the water pump and the pressure pot; and
controlling, with a blast control switch, actuation of a control
valve between an open state and a closed state to thereby control
the pressurizing water flow to the pressure pot and the blast
slurry flow through the media line.
14. The method of claim 13, wherein: the control valve is disposed
on the water line; and the control valve allows the pressurizing
water flow to flow to and pressurize the pressure pot when in the
open state, and the control valve prevents the pressurizing water
flow from flowing to and pressurizing the pressure pot when in the
closed state.
15. The method of claim 13, wherein: the control valve is disposed
on a pump air supply line supplying pump air to the water pump to
power the water pump; and the control valve allows the pump air to
flow to and power the water pot when in the open state, and the
control valve prevents the pump air from flowing to and powering
the water pump when in the closed state.
16. The method of claim 13, wherein: the control valve mechanically
interacts with the water pump to control pumping by the water pump;
and the control valve restrains reciprocation of a pump component
of the water pump when in the closed state to prevent the water
pump from pumping water to the pressure pot, and allows
reciprocation of the pump component when in the open state to allow
the water pump to pump the water to the pressure pot.
17. The method of claim 13, further comprising: controlling, with
the blast control switch, actuation of a blast air controller
disposed on the air supply line between an open controller state,
where the blast air controller allows the compressed air to flow to
the junction through the air supply line, and a closed controller
state, where the blast air controller prevents the compressed air
from flowing to the junction through the air supply line; wherein
the blast air controller is configured to be in the open controller
state when the control valve is in the open state, and the blast
air controller is configured to be in the closed controller state
when the control valve is in the closed state.
18. The method of claim 17, further comprising: delaying shifting
of the control valve to the open state until after the blast air
controller shifts to the open controller state; and delaying
shifting of the blast air controller to the closed controller state
until after the control valve shifts to the closed state.
19. A control system for a vapor abrasive blast system having a
pressure pot that stores a supply of blast slurry, a compressor for
providing a flow of compressed air through an air supply line to a
blast line, and a water pump for pumping water to the pressure pot
to thereby pressurize the pressure pot and drive the blast slurry
downstream out of the pressure pot through a media line to the
blast line where the blast slurry can be entrained in the
compressed air and carried out of a nozzle, the control system
comprising: a control valve configured to shift between an open
state and a closed state to control the water flow to the pressure
pot from the water pump, wherein the control valve is configured to
prevent the water from flowing to and pressurizing the pressure pot
when in the closed state and to allow the water to flow to and
pressurize the pressure pot when in the open state; a blast air
controller disposed on the air supply line upstream of the blast
line, the blast air controller configured to shift between an open
controller state and a closed controller state to control the
compressed air flow to the blast line, wherein the blast air
controller is configured to prevent the compressed air from flowing
to the blast line when in the closed controller state and to allow
the compressed air to flow to the blast line when in the open
controller state; and a blast control switch configured to control
the control valve between the open state and the closed state, and
further configured to control the blast air controller between the
open controller state and the closed controller state; wherein the
flow of blast slurry out of the pressure pot is activated and
deactivated by the water flow to the pressure pot.
20. The control system of claim 19, wherein there is no valve
disposed downstream of the pressure pot to control the flow of
blast slurry through any one of the media line, the blast line, and
the nozzle during blasting
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to U.S. Provisional
Application No. 62/519,235 filed Jun. 14, 2017, and entitled
"ABRASIVE BLAST SYSTEM," the disclosure of which is hereby
incorporated in its entirety.
BACKGROUND
[0002] This disclosure relates generally to abrasive blast systems.
More specifically, this disclosure relates to an abrasive blast
system eliminating an on/off flow control valve downstream of the
pressure pot.
[0003] Blasting systems in the surface preparation industry
generally use dry, wet, slurry, vapor abrasive, or ultra-high
pressure water blast technologies to remove dirt, paint, or rust
from a substrate. Vapor blast systems use a mixture of air, water,
and an abrasive media--such as garnet or walnut shells--to provide
the desired surface treatment. Vapor blast systems often include a
pump and a pressure pot containing an abrasive media having a
density greater than water. Pumping water to the pressure pot
pressurizes it and allows the abrasive media and water to mix. The
pressurized media and water mixture is then plumbed into a conduit
of a high flowing air stream to mix the two streams before
expelling the mixture from a hose and nozzle. The flow of media and
water into the compressed air stream is typically controlled by a
valve located downstream of the pressure pot. The valve is in
direct contact with the mixture of media and water, and is thus
subject to wear. As such, the valve requires frequent maintenance
and/or replacement.
SUMMARY
[0004] According to an aspect of the disclosure, an abrasive blast
system includes a water pump, a pressure pot, an air supply line
extending from an air source, a media line extending from the
pressure pot to the air supply line, a blast line extending
downstream from a junction of the media line and the air supply
line to a nozzle, a control valve, and a blast control switch. The
water pump is configured to pump a flow of water from a water
source to the pressure pot through a water line. The control valve
is configured to shift between an open state and a closed state to
control the flow of water to the pressure pot to control the flow
of blast slurry from the pressure pot to the media line. The blast
control switch is controllable between an activated state and a
deactivated state and is configured to actuate the control valve
between the open state and the closed state.
[0005] According to another aspect of the disclosure, a method
includes generating a compressed air flow and directing the
compressed air flow to an air supply line; pumping, with a water
pump, a pressurizing water flow; and controlling with a blast
control switch, actuation of a control valve between an open state
and a closed state to thereby control the pressurizing water flow
to the pressure pot and the blast slurry flow through the media
line. The air supply line extends to a junction with a media line
that extends from a pressure pot. The media line is configured to
convey a blast slurry flow to the junction from the pressure pot.
The water pump is configured to pump the pressurizing water flow to
the pressure pot through a water line extending between the water
pump and the pressure pot.
[0006] According to yet another aspect of the disclosure, a control
system is for a vapor abrasive blast system having a pressure pot
that stores a supply of blast slurry, a compressor for providing a
flow of compressed air through an air supply line to a blast line,
and a water pump for pumping water to the pressure pot to thereby
pressurize the pressure pot and drive the blast slurry downstream
out of the pressure pot. The blast slurry is driven through a media
line to the blast line where the blast slurry is entrained in the
compressed air and carried out of a nozzle. The control system
includes a control valve, a blast air controller, and a blast
control switch. The control valve is configured to shift between an
open state and a closed state to control the water flow to the
pressure pot from the water pump. The control valve is configured
to prevent the water from flowing to and pressurizing the pressure
pot when in the closed state and to allow the water to flow to and
pressurize the pressure pot when in the open state. The blast air
controller is disposed on the air supply line upstream of the blast
line. The blast air controller is configured to shift between an
open controller state and a closed controller state to control the
compressed air flow to the blast line. The blast air controller is
also configured to prevent the compressed air from flowing to the
blast line when in the closed controller state and to allow the
compressed air to flow to the blast line when in the open
controller state. The blast control switch actuates the control
valve between the open state and the closed state and actuates the
blast air controller between the open controller state and the
closed controller state. The flow of blast slurry out of the
pressure pot is activated and deactivated by the water flow to the
pressure pot.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a block diagram of a vapor blast system.
[0008] FIG. 2 is a schematic diagram of a vapor blast system with a
control valve configured to control the flow of water to the
pressure pot.
[0009] FIG. 3 is a schematic diagram of a vapor blast system with a
control valve configured to control the flow of air to the water
pump.
[0010] FIG. 4 is a schematic diagram of a vapor blast system with a
control valve configured to control the water pump.
DETAILED DESCRIPTION
[0011] FIG. 1 is a simplified schematic diagram of vapor blast
system 10, which is a system that entrains a blast slurry of water
and blast media (e.g. garnet, walnut shells, or any other suitable
blasting media) in a flow of compressed air to perform coating
removal and surface preparation. Vapor blast system 10 includes
compressor 12, blast air controller 14, water source 16, water pump
18, pressure pot 20, control valves 22a-22c, blast control switch
24, nozzle 26, control logic 28, communication lines 29, air supply
line 30, system line 32, water inlet line 34, pressurization line
36, media line 38, blast line 40, and junction 42.
[0012] Compressor 12 is an air compressor that generates a flow of
compressed air to entrain the blast slurry and to power various
components of vapor blast system 10. Compressor 12 is configured to
generate the flow of compressed air whenever vapor blast system 10
is operating. Air supply line 30 extends from compressor 12 to
junction 42. Junction 42 is the location where media line 38 and
air supply line 30 join to form blast line 40. Blast line 40
extends from junction 42 of air supply line 30 and media line 38 to
nozzle 26. Nozzle 26 ejects a spray of entrained blast slurry for
application to a surface.
[0013] System line 32 branches from air supply line 30 upstream of
blast air controller 14 and extends to water pump 18. The
compressed air from compressor 12 flows into air supply line 30. A
blast portion of the compressed air ("blast air") flows downstream
through air supply line 30 to nozzle 26, and a system portion of
the compressed air ("system air") flows into system line 32. System
line 32 provides the system air to water pump 18, and the system
air powers water pump 18. Water pump 18 includes a shuttle valve
that directs the system air to power reciprocation of the piston of
water pump 18. While water pump 18 is described as a pneumatically
powered pump, it is understood that water pump 18 can be of any
desired configuration, such as an electric pump or a hydraulic
pump.
[0014] Blast air controller 14 is disposed on air supply line 30
and is controllable between an open state, in which blast air
controller 14 allows the blast portion to flow downstream to
junction 42, and a closed state, in which blast air controller 14
prevents the compressed air from flowing downstream to junction 42.
Blast air controller 14 is thereby configured to control blasting
by controlling the flow of blast air to nozzle 26.
[0015] Water inlet line 34 extends from water source 16 to water
pump 18. Pressurization line 36 extends from water pump 18 to
pressure pot 20 and supplies the pumped water to pressure pot 20.
Water source 16 stores a supply of water that water pump 18 pumps
to pressure pot 20 through pressurization line 36. The pumped water
pressurizes pressure pot 20 and generates the blast slurry.
[0016] Media line 38 extends from pressure pot 20 to junction 42.
Media line 38 conveys the blast slurry from pressure pot 20 to
junction 42 where the blast slurry is entrained in the blast air
from air supply line 30. The entrained blast slurry is driven out
of nozzle 26 by the blast air. Junction 42 is located at a higher
elevation than the maximum fill level of pressure pot 20 to prevent
the blast media from being gravity fed through media line 38 to
blast line 40.
[0017] Control valves 22a-22c are configured to control the flow of
pumped water to pressure pot 20 to thereby control the flow of
blast slurry out of pressure pot 20. Control valve 22a is disposed
on pressurization line 36 between water pump 18 and pressure pot
20. Control valve 22b is disposed on system line 32 upstream of
water pump 18. Control valve 22c is disposed on water pump 18.
Control valve 22c directly interfaces with water pump 18 and
mechanically controls pumping by water pump 18.
[0018] Control valves 22a-22c are controllable between an open
state, where control valves 22a-22c allow the pumped water to flow
to pressure pot 20, and a closed state, where control valves
22a-22c prevent the pumped water from flowing to pressure pot 20.
Control valves 22a-22c are disposed upstream of pressure pot 20
such that control valves 22a-22c do not interface directly with
either the blast media or the blast slurry. While vapor blast
system 10 is shown as including control valve 22a, control valve
22b, and control valve 22c, it is understood that vapor blast
system 10 need include only one of control valve 22a, control valve
22b, and control valve 22c to control the flow of pumped water to
pressure pot 20.
[0019] Control valves 22a-22c are of any suitable configuration for
controlling the flow of pumped water to pressure pot 20. Control
valve 22a is a water valve on pressurization line 36 that controls
the flow of pumped water to pressure pot 20. As such, control valve
22a directly controls the flow of pressurized water to pressure pot
20. Control valve 22b is an air valve on system line 32 that
controls the flow of system air to water pump 18. Control valve 22b
controls the flow of water to pressure pot 20 by controlling
activation of water pump 18. Control valve 22c mechanically
interfaces with water pump 18 to control the flow of water to
pressure pot 20. In some examples, control valve 22c is a
mechanical device configured to restrict reciprocation of the
shuttle of the shuttle valve that directs the system air within
water pump 18 to power water pump 18. For example, control valve
22c can include a pin that control valve 22c extends and retracts
to inhibit and allow reciprocation of the shuttle.
[0020] Blast control switch 24 is connected to blast air controller
14 and control valves 22a-22c. Blast control switch 24 controls
blast air controller 14 and control valves 22a-22c between their
respective open states and closed states. Blast control switch 24
is configured to be switched between an activated state and a
deactivated state by the user to control the flow of the entrained
blast slurry out of nozzle 26. Blast control switch 24 can
communicate with and control blast air controller 14 and control
valves 22a-22c in any suitable manner. For example, blast control
switch 24 can include a trigger that the user depresses to place
blast control switch 24 in the activated state and that the user
releases to place blast control switch 24 in the deactivated
state.
[0021] Communication lines 29 extend from blast control switch 24
and provide commands to blast air controller 14, control valves
22a-22c, and control logic 28 from blast control switch 24.
Communication lines 29 can be of any suitable form for
communicating commands from blast control switch 24, such as
electronic or pneumatic lines.
[0022] In one example, blast control switch 24 is a pneumatic
switch and blast air controller 14 and control valves 22a-22c are
pneumatically actuated. In such an example, system line 32 can
extend to both blast air controller 14 and control valves 22a-22c
to provide compressed air to blast air controller 14 and control
valves 22a-22c to actuate blast air controller 14 and control
valves 22a-22c between their respective states. Blast control
switch 24 directs the flow of compressed air to both blast air
controller 14 and control valves 22a-22c to control the respective
states of blast air controller 14 and control valves 22a-22c.
[0023] In another example, blast air controller 14 communicates
electronically through either wired or wireless communication
links, such as communication lines 29, with both blast air
controller 14 and control valves 22a-22c. Blast air controller 14
provides an activation signal to blast air controller 14 and
control valves 22a-22c to cause blast air controller 14 and control
valves 22a-22c to shift to their respective open states. Blast air
controller 14 provides a deactivation signal to blast air
controller 14 and control valves 22a-22c to cause blast air
controller 14 and control valves 22a-22c to shift to their
respective closed states.
[0024] Control logic 28 is in communication, via communication
lines 29, with blast control switch 24, blast air controller 14,
and control valves 22a-22c. Control logic 28 is configured to
implement a delay in actuation between blast air controller 14 and
control valves 22a-22c. Control logic 28 can be of any suitable
configuration for implementing a delay between actuation of blast
air controller 14 and control valves 22a-22c. For example, control
logic 28 can include any one or more of a microprocessor, a
controller, a digital signal processor (DSP), an application
specific integrated circuit (ASIC), a field-programmable gate array
(FPGA), or other equivalent discrete or integrated logic circuitry.
In some examples, control logic 28 is an air logic controller such
that compressed air from compressor 12 is the control medium. In
each example, control logic 28 is configured to cause blast air
controller 14 to shift to the open state prior to control valves
22a-22c shifting to the open state, and to cause blast air
controller 14 to shift to the closed state after control valves
22a-22c shift to the closed state. As such, control logic 28
ensures that blast air is flowing through blast line 40 whenever
control valves 22a-22c are in the open state, thereby ensuring that
the blast slurry flowing out of media line 38 is entrained and
carried out of nozzle 26.
[0025] During operation, the user controls the flow of entrained
blast slurry out of nozzle 26 via blast control switch 24. Blast
air controller 14 and control valves 22 are configured to be in a
similar state. As such, both blast air controller 14 and control
valve are in the open state when blasting is desired, and both
blast air controller 14 and control valve 22 are in the closed
state when blasting is not desired.
[0026] When blasting is desired, blast control switch 24 causes
both blast air controller 14 and control valves 22a-22c to shift
the open state. With blast air controller 14 in the open state the
blast air flows through air supply line 30 to junction 42,
downstream through blast line 40 and out of nozzle 26. With control
valves 22a-22c in the open state the pumped water from water pump
18 flows through pressurization line 36 and into pressure pot 20.
The pumped water causes the pressure in pressure pot 20 to rise and
the increased pressure drives the blast slurry out of pressure pot
through media line 38. The blast slurry flows through media line 38
to junction 42 where the blast slurry is entrained in the blast air
and sprayed out of nozzle 26.
[0027] Control valves 22a-22c control the flow of pumped water to
pressure pot 20 in different manners. As discussed above, control
valve 22a is a water valve configured to directly control the water
flow through pressurization line 36. With control valve 22a in the
closed state the pumped water from water pump 18 deadheads at
control valve 22a. With control valve 22a in the open state, the
pumped water flows downstream into pressure pot 20. Control valve
22b is an air valve configured to control the system air flow to
water pump 18. With control valve 22b in the closed state the
system air cannot flow to water pump 18 to power water pump 18, so
water pump 18 does not generate the pressurizing water flow. With
control valve 22b in the open state, the system air flows to and
powers water pump 18, and water pump 18 pumps the pressurizing
water to pressure pot 20. Control valve 22c is a mechanical device
interacting with water pump 18 to control activation of water pump
18. With control valve 22c in the closed state, control valve 22c
physically inhibits the oscillation of the shuttle of water pump
18, thereby preventing the shuttle from directing the system air
that powers water pump 18 such that water pump 18 does not generate
the pressuring water flow. With control valve 22c in the open
state, the shuttle can oscillate and direct the system air such
that water pump 18 pumps the pressurizing water flow to water pump
18.
[0028] In some examples, blast air controller 14 shifts to the open
state prior to control valves 22a-22c shifting to the open state.
For example, blast control switch 24 can be configured to implement
of delay between sending the open command to blast air controller
14 and sending the open command to control valves 22a-22c. Control
logic 28 can also implement the delay. Actuating blast air
controller 14 to the open state prior to actuating control valves
22a-22c to the open state ensures that the blast air is already
flowing through junction 42 and blast line 40 prior to the blast
slurry first reaching junction 42. A uniform flow of entrained
blast slurry is thereby generated at the beginning of the blast
operation.
[0029] The user stops the flow of entrained blast slurry by placing
blast control switch 24 in the deactivated state. For example, the
user can release the trigger of blast control switch 24. In the
deactivated state, blast control switch 24 causes both blast air
controller 14 and control valves 22a-22c to shift to their
respective closed states. The blast air is prevented from flowing
to blast line 40 with blast air controller 14 in the closed state.
The pumped water is prevented from flowing to and pressurizing
pressure pot 20 with control valves 22 in the closed state.
Preventing the pumped water from flowing to pressure pot 20 causes
the pressure within pressure pot 20 to decrease as the blast slurry
flows out of pressure pot 20 through media line 38. The pressure
drops to a sufficiently low level such that the blast slurry is not
driven through media line 38 to junction 42 by the pressure level
in pressure pot 20. As such, shutting off the flow of pressurizing
water to pressure pot 20 also shuts off the flow of blast slurry
out of pressure pot 20.
[0030] Blast air controller 14 to shift to the closed state after
control valves 22a-22c shift to the closed state. For example,
blast control switch 24 can be configured to implement of delay
between sending the close command to blast air controller 14 and
sending the close command to control valves 22a-22c. Control logic
28 can also implement the delay. Shifting blast air controller 14
to the closed state after shifting control valves 22a-22c to the
closed state ensures that the blast air continues to flow through
junction 42 and blast line 40 as the pressure drops in pressure pot
20. The blast air carries any excess flow from pressure pot 20 out
of nozzle 26, thereby preventing an undesired plug of blast slurry
from forming in blast line 40 when blast control switch 24 is
placed in the deactivated state.
[0031] Control valves 22a-22c deactivate the flow of blast slurry
out of pressure pot 20 without directly interacting with the blast
slurry or the blast media. Instead, control valves 22a-22c directly
interface with the flow of pressurizing water, the flow of system
air to water pump 18, or mechanically with water pump 18.
Controlling the flow of blast slurry by controlling the flow of
pumped water to pressure pot 20 prevents control valves 22a-22c
from experiencing wear caused by directly interfacing with the
blast slurry. Vapor blast system 10 does not require any valve in
the direct flow of blast media, on either the media line 38 or the
blast line 40. Blasting media flow is instead controlled entirely
by controlling the flow of water into pressure pot 20. Eliminating
valves in the flowpath of the blast media reduces maintenance
requirements for vapor blast system 10, thereby reducing
maintenance costs and downtime. In addition, positioning junction
42 at a higher elevation than the maximum fill level of pressure
pot 20 prevents any undesired flow of blast slurry out of media
line 38 to junction 42 when the blast air flow is stopped.
[0032] Control logic 28 also increases efficiency and provides
increased spray quality. Control logic 28 ensures that the blast
air begins flowing to blast line 40 prior to the blast slurry
flowing to blast line 40, and that the blast air continues to flow
to blast line 40 after the blast slurry stops flowing to blast line
40. Delaying the flow of blast slurry to blast line 40 until after
blast air is flowing to blast line 40 ensures an even high-quality
spray of entrained blast slurry at nozzle 26 as blasting begins.
Delaying cessation of the flow of blast air to blast line 40 until
after the blast slurry stops flowing to blast line 40 prevents
undesired accumulation of blast media in blast line 40, which can
lead to accumulation of blast slurry in blast line 40 that can
obstruct the flow of material and air and can cause undesired spray
qualities when blasting is reinitiated.
[0033] FIG. 2 is a schematic diagram of vapor blast system 100,
which includes compressor 12, blast air controller 14, water source
16, water pump 18, pressure pot 20, blast control switch 24, nozzle
26, air supply line 30, system line 32, water inlet line 34,
pressurization line 36, media line 38, blast line 40, junction 42,
disconnect 44, system valve 46, pump pressure regulator 48, flow
valve 50, check valve 52, air filter 54, pressure gauge 56,
pressure relief 58, system control line 60a, system control line
60b, pump control line 62, blast control line 64, pressure control
line 66, and control valve 122. Blast air controller 14 includes
air pressure regulator 68 and blast air regulator 70.
[0034] Compressor 12 is an air compressor configured to generate a
flow of compressed air and to provide the flow of compressed air to
air supply line 30. The compressed air splits as it flows through
air supply line 30. Water pump 18 is configured to draw water from
water source 16 and pump the water downstream to pressure pot 20 to
pressurize pressure pot 20. Pressure pot 20 stores a blast slurry
comprised of water and abrasive blasting media. The pressure within
pressure pot 20 causes the blast slurry to flow downstream from
pressure pot 20 through media line 38 and to blast line 40, where
the blast slurry is entrained in the blast air flowing through air
supply line 30. The entrained blast slurry is conveyed downstream
to nozzle 26 and is sprayed from nozzle 26 and applied to the
desired blast surface.
[0035] Air supply line 30 extends from compressor 12 to blast line
40. System line 32 branches off of air supply line 30 and receives
a portion of the compressed air flow from air supply line 30. A
blast portion of the compressed air ("blast air") flows downstream
through air supply line 30 and a system portion of the compressed
air ("system air") flows through system line 32.
[0036] Blast air controller 14 controls the flow of the blast air
through air supply line 30. Blast air regulator 70 is disposed on
air supply line 30 and controls the flow of blast air downstream
through air supply line 30. Blast air regulator 70 is positionable
at any desired position between a fully open position, allowing a
maximum flow of blast air through air supply line 30, and a fully
closed position, preventing any air from flowing downstream through
air supply line 30. Blast air regulator 70 is normally-closed and
is actuated to the open state by the system air when blasting is
desired. Air pressure regulator 68 controls the flow of system air
to blast air regulator 70, and the pressure provided by the system
air determines the degree that blast air regulator 70 opens. The
user controls the blast air pressure via air pressure regulator 68.
As such, air pressure regulator 68 controls the flow of system air
to blast air regulator 70, and blast air regulator 70 controls the
flow of blast air through air supply line 30.
[0037] Air filter 54 is disposed on system line 32 and is
configured to remove contaminants from the compressed air flowing
in system line 32. Disconnect 44 is disposed on system line 32.
Disconnect 44 is a flow control valve that controls the flow of
compressed air into system line 32, and in some examples provides
an emergency stop for vapor blast system 100. With disconnect 44 in
an open state, the compressed air in system line 32 can flow
downstream through disconnect 44 to power and control various
components of vapor blast system 100. With disconnect 44 in a
closed state, the compressed air in system line 32 cannot flow
downstream past disconnect 44 to power the components of vapor
blast system 100 and vapor blast system 100 is thereby prevented
from blasting.
[0038] System line 32 extends downstream from disconnect 44 to
system valve 46 and pump pressure regulator 48. Pump control line
62 is a portion of system line 32 that extends from pump pressure
regulator 48 to water pump 18. Pump pressure regulator 48 controls
the flow of system air to water pump 18 to thereby control the
speed of and the pressure generated by water pump 18. Water pump 18
is configured to draw water from water source 16 through water
inlet line 34 and to pump the water downstream to pressurization
line 36. Flow valve 50 is disposed on pressurization line 36 and is
configured to regulate the flow rate of water from water pump 18 to
pressure pot 20. Flow valve 50 can be of any suitable form for
regulating the water flow, such as one or more needle valves. The
user sets the position of internal components of flow valve 50 to
set the flow rate of the pressurizing water flowing to pressure pot
20. The flow rate of the pressurizing water to pressure pot 20 is
directly related to the flow rate of the blast slurry out of
pressure pot 20, such that the flow rate of the blast slurry is
controlled by controlling the flow through flow valve 50. Check
valve 52 is disposed on pressurization line 36 between control
valve 122 and pressure pot 20. Check valve 52 prevents water and
media from backflowing out of pressure pot 20 to pressurization
line 36.
[0039] Control valve 122 is disposed on pressurization line 36
between water pump 18 and pressure pot 20. Control valve 122 is
controllable between an open state, where the pumped water can flow
downstream through control valve 122 to pressure pot 20, and a
closed state, where the pumped water is prevented from flowing to
pressure pot 20. Control valve 122 is a normally-open valve such
that control valve 122 remains in the open state unless actuated to
the closed state. Control valve 122 can be any suitable valve for
controlling the flow of water through pressurization line 36, such
as a ball valve, a pinch valve, a disk valve, a gate valve, or any
other suitable valve. Control valve 122 controls the pressurization
of pressure pot 20, thereby controlling the flow of blast slurry
out of pressure pot 20.
[0040] Pressure pot 20 is a pressure vessel configured to store the
blast slurry. Pressure gauge 56 is configured to provide an
indication of the pressure level in pressure pot 20 to the user.
Pressure relief 58 is a valve that allows the user to relieve the
pressure within pressure pot 20 prior to opening pressure pot 20.
Media line 38 extends downstream from pressure pot 20 and merges
with air supply line 30 at junction 42. Media line 38 provides the
blast slurry from pressure pot 20 to junction 42, where the blast
slurry is entrained in the blast air flowing through air supply
line 30. Blast line 40 extends from junction 42 to nozzle 26 and
conveys the entrained blast slurry to nozzle 26. Nozzle 26 is open
and, in some examples, does not contain any internal mechanism for
controlling the flow of entrained blast slurry out of nozzle
26.
[0041] Media line 38 is open between pressure pot 20 and blast line
40, and no valve is disposed on media line 38 to control the flow
of blast slurry through media line 38. Instead, the flow of blast
slurry through media line 38 is controlled by the pressure in
pressure pot 20. Junction 42 of media line 38 and air supply line
30 is located at a higher elevation than the maximum fill level of
pressure pot 20 to prevent the blast slurry from being gravity fed
from pressure pot 20 to blast line 40 when blasting is not desired.
In addition, media line 38 is preferably rigid, which further
prevents accumulation of the blast slurry in media line 38 when
vapor blast system 100 is deactivated.
[0042] System control line 60a branches off of system line 32 and
extends to blast control switch 24. System control line 60b extends
from blast control switch 24 to system valve 46. A control portion
of the compressed air from compressor 12 flows into system control
line 60a. Blast control switch 24 is controllable between an
activated state, where the control air can flow from system control
line 60a to system control line 60b through blast control switch
24, and a deactivated state, where system control line 60a is
disconnected from system control line 60b to prevent the control
air from flowing from system control line 60a to system control
line 60b. In some examples, blast control switch 24 is integrated
with or closely located to nozzle 26 such that the same user can
actuate blast control switch 24 and aim nozzle 26. For example,
blast control switch 24 can be actuated between the activated state
and the deactivated state by the user depressing a trigger of blast
control switch 24.
[0043] While blast control switch 24 is described as a pneumatic
controller, it is understood that blast control switch 24 can be of
any desired form for controlling the state of system valve 46. For
example, blast control switch 24 can communicate electronically,
though either a wired or wireless connection, with system valve 46
to control the state of system valve 46. In some examples, blast
control switch 24 can directly communicate with blast air
controller 14 and control valve 122 to control the respective
states of blast air controller 14 and control valve 122. For
example, each of blast air controller 14 and control valve 122 can
be electrically actuated by a solenoid valve, and blast air
controller 14 can provide electrical signals to the respective
solenoid valves to actuate blast air controller 14 and control
valve 122 between the open and closed states.
[0044] Blast control line 64 and pressure control line 66 extend
downstream from system valve 46. Blast control line 64 extends to
air pressure regulator 68 and from air pressure regulator 68 to
blast air regulator 70. Pressure control line 66 extends to control
valve 122. System valve 46 directs the flow of system air to either
blast control line 64 or pressure control line 66 depending on the
state of system valve 46. System valve 46 directs the system air to
blast control line 64 and away from pressure control line 66 when
system valve 46 is in a system-on state. Directing the system air
to blast control line 64 causes blast air regulator 70 to shift to
the open state and causes control valve 122 to return to the open
state, as control valve 122 is normally-open. System valve 46
directs the system air to pressure control line 66 and away from
blast control line 64 when system valve 46 is in a system-off
state. Directing the system air to pressure control line 66 causes
control valve 122 to shift to the closed state and blast air
regulator 70 to return to the closed state, as blast air regulator
70 is normally-closed.
[0045] During operation, compressor 12 is activated and generates
and provides a compressed air flow to air supply line 30. The user
places vapor blast system 100 in operation by shifting disconnect
44 to the open state such that the system portion can flow
downstream from disconnect 44 through system line 32. The blast air
portion flows downstream through air supply line 30 towards blast
line 40. The system air flows through system line 32 to system
valve 46 and water pump 18. The control air flows to blast control
switch 24 through system control line 60a. Blast control switch 24
is normally-closed such that blast control switch 24 prevents the
control air from flowing to system valve 46 through system control
line 60b.
[0046] The system air flowing to pump control line 62 initially
flows through pump pressure regulator 48, which can be set at any
desired position by the user to control the water pressure
generated by water pump 18. The system air flows to and powers
water pump 18. Water pump 18 draws water from water source 16
through water inlet line 34 and pumps the water downstream through
pressurization line 36. The water flows through flow valve 50,
which limits the flow rate of the water to thereby limiting the
flow rate of the blast slurry leaving pressure pot 20, and to
pressure pot 20 through pressurization line 36. Control valve 122
is disposed on pressurization line 36 and controls the flow of
water to pressure pot 20. With control valve 122 in the closed
state, the water deadheads at control valve 122 and does not flow
to pressure pot 20.
[0047] System valve 46 is in the system-off state until blast
control switch 24 is actuated to an activated state, where system
control line 60a is connected to system control line 60b. In the
system-off state system valve 46 directs the system air to pressure
control line 66. The system air flows through pressure control line
66 to control valve 122 and causes control valve to shift to and
remain in the closed state. In the closed state control valve 122
prevents the water pumped into pressurization line 36 from flowing
to pressure pot 20. As such, pressure pot 20 is not pressurized by
the water and the blast slurry does not flow out of pressure pot 20
to media line 38. In the system-off state system valve 46 prevents
the system air from flowing to blast control line 64. Blast air
regulator 70 thus remains in the normally-closed state and prevents
the blast air from flowing downstream through air supply line 30.
As such, with blast control switch 24 in the deactivated state,
both blast air regulator 70 and control valve 122 are in their
respective closed states.
[0048] To initiate blasting, the user actuates blast control switch
24 to an activated state where system control line 60a is fluidly
connected to system control line 60b such that the control air
flows to system control line 60b. System control line 60b provides
the control air to system valve 46, where the control air causes
system valve 46 to shift to the system-on state. In the system-on
state system valve 46 directs the system air to blast control line
64 and prevents the system air from flowing to pressure control
line 66. The system air flows through blast control line 64 to
blast air regulator 70, where the system air causes blast air
regulator 70 to shift to the open state. With blast air regulator
70 in the open state the blast air flows downstream through air
supply line 30 past blast air regulator 70 and to blast line 40.
Without the system air to maintain control valve 122 in the closed
state, control valve 122 returns to the normally-open state. As
such, both blast air regulator 70 and control valve 122 are open
with blast control switch 24 in the activated state.
[0049] With control valve 122 in the open state the pumped water
from water pump 18 flows through pressurization line 36 to pressure
pot 20. The pumped water pressurizes pressure pot 20, and the
increased pressure within pressure pot 20 drives the blast slurry
out of pressure pot 20 and downstream through media line 38 to
junction 42. The blast slurry is entrained in the blast portion of
air at junction 42, and the entrained blast slurry is driven
downstream through blast line 40 and out of nozzle 26.
[0050] To stop blasting the user returns blast control switch 24 to
the deactivated state, such as by releasing the trigger of blast
control switch 24. In the deactivated state blast control switch 24
prevents the control air from flowing to system control line 60b
from system control line 60a. System valve 46 returns to the
system-off state. In the system-off state system valve 46 prevents
the system air from flowing to blast air regulator 70 through blast
control line 64, such that blast air regulator 70 returns to the
normally-closed position, and directs the system air to control
valve 122 through pressure control line 66, such that control valve
122 shifts to the closed state. Control valve 122 prevents the
water from flowing to and pressurizing pressure pot 20 when in the
closed state. Without a flow of pressurizing water the pressure in
pressure pot 20 drops. The decreased pressure at an insufficient
level to drive the blast slurry downstream through media line 38.
Blasting is thus ceased by ceasing the flow of water to pressure
pot 20.
[0051] Vapor blast system 100 includes logic, such as control logic
28 (FIG. 1), to prevent undesired accumulation of blast media in
blast line 40. When system valve 46 shifts to the system-on
position, the logic ensures that blast air regulator 70 shifts to
the open position prior to control valve 122 shifting to the open
position. As such, the blast air flows to and through blast line 40
prior to the blast slurry beginning to flow to blast line 40.
Flowing the blast air through blast line 40 prior to introducing
the blast slurry prevents undesired buildup of blast slurry in
blast line 40 and ensures a smooth, high-quality flow of the
entrained blast slurry out of nozzle 26. When system valve 46
shifts to the system-off state, the logic ensures that control
valve 122 shifts to the closed state prior to blast air regulator
70 shifting to the closed state. Shifting control valve 122 to the
closed state prior to shifting blast air regulator 70 to the closed
state ensures that the blast air continues to flow to blast line 40
as pressure pot 20 depressurizes, thereby preventing undesired
accumulation of blast slurry in blast line 40.
[0052] Vapor blast system 100 provides significant advantages.
Control valve 122 is disposed upstream of pressure pot 20 and
controls the flow of pressurizing water to pressure pot 20.
Controlling the flow of pressurizing water to pressure pot 20
controls pressurization of pressure pot 20 and thus controls the
flow of blast slurry out of pressure pot 20. There are no valves
disposed downstream of pressure pot 20. Blasting is instead
controlled directly by controlling the pressurization of pressure
pot 20. Eliminating valves downstream of pressure pot 20 in the
flowpath of the blast media reduces maintenance requirements for
vapor blast system 100, thereby reducing maintenance costs and
downtime. In addition, positioning junction 42 at a higher
elevation than the maximum fill level of pressure pot 20 prevents
undesired flow of blast slurry out of media line 38. The control
logic ensures that the blast air begins flowing through blast line
40 prior to the blast slurry flowing to blast line 40 and that the
blast air continues to flow through blast line 40 as pressure pot
20 depressurizes, which eliminates clogging and undesired
accumulation of blast slurry in blast line 40.
[0053] FIG. 3 is a schematic diagram of vapor blast system 200.
Vapor blast system 200 includes compressor 12, blast air controller
14, water source 16, water pump 18, pressure pot 20, blast control
switch 24, nozzle 26, air supply line 30, system line 32, water
inlet line 34, pressurization line 36, media line 38, blast line
40, junction 42, disconnect 44, system valve 46, pump pressure
regulator 48, flow valve 50, check valve 52, air filter 54,
pressure gauge 56, pressure relief 58, system control line 60a,
system control line 60b, pump control line 62, blast control line
64, pressure control line 66, and control valve 222. Blast air
controller 14 includes air pressure regulator 68 and blast air
regulator 70.
[0054] Vapor blast system 200 is substantially similar to vapor
blast system 10 shown in FIG. 1 and vapor blast system 100 shown in
FIG. 2, except control valve 222 is located on system line 32
upstream of water pump 18, similar to control valve 22b (FIG. 1).
While control valve 222 is shown as disposed upstream of pump
pressure regulator 48, it is understood that control valve 222 can
disposed at any desired location for controlling the system air
flow to water pump 18, such as on pump control line 62 between pump
pressure regulator 48 and water pump 18.
[0055] Pressure control line 66 extends from system valve 46 to
control valve 222. Control valve 222 controls the flow of system
air to water pump 18. Control valve 222 is a normally-open valve
that shifts to the closed state when system valve 46 is in the
system-off state. Control valve 222 returns to the open state when
system valve 46 is in the system-on state such that system valve 46
directs the system air to blast control line 64.
[0056] Control valve 222 is controlled between the open state and
the closed state to control pressurization of pressure pot 20.
Actuating control valve 222 to the closed state stops the flow of
system air to water pump 18, thereby deactivating water pump 18.
Deactivating water pump 18 prevents water pump 18 from pumping
water to pressure pot 20 through pressurization line 36, thereby
allowing the pressure in pressure pot 20 to drop. The decreased
pressure in pressure pot 20 is sufficiently low such that the
pressure does not drive the blast slurry downstream to blast line
40 through media line 38. Pressure pot 20 remains at the decreased
pressure and the blast slurry remains in pressure pot 20 until
control valve 222 shifts to the open state.
[0057] System valve 46 causes control valve 222 to shift to the
open state when system valve 46 is in the system-on state. In the
open state, control valve 222 allows the system air to flow to and
power water pump 18. Water pump 18 draws water from water source 16
and pumps the water to pressure pot 20 through pressurization line
36. The pumped water increases the pressure in pressure pot 20, and
the increased pressure drives the blast slurry downstream out of
pressure pot 20 through media line 38 to junction 42, where the
blast slurry is entrained in the blast air and driven downstream
though blast line 40 and out of nozzle 26.
[0058] Vapor blast system 200 includes logic, such as control logic
28 (FIG. 1), to prevent accumulation of the blast slurry in blast
line 40. When system valve 46 shifts to the system-on state, the
logic ensures that blast air regulator 70 shifts to the open state
prior to control valve 222 shifting to the open state. When system
valve 46 shifts to the system-off state, the logic ensures that
control valve 222 shifts to the closed state prior to blast air
regulator 70 shifting to the closed state.
[0059] Vapor blast system 200 and control valve 222 provide
significant advantages. Control valve 222 controls the flow of
system air to water pump 18 to control the flow of blast slurry out
of pressure pot 20. Control valve 222 deactivates water pump 18 by
shutting off the flow of system air to water pump 18. Control valve
222 interfaces with only the system air and is not subject to the
wear generated by interacting with the blast media in the blast
slurry, thereby reducing maintenance and replacement costs and
simplifying vapor blast system 200.
[0060] FIG. 4 is a schematic diagram of vapor blast system 300.
Vapor blast system 210 includes compressor 12, blast air controller
14, water source 16, water pump 18, pressure pot 20, blast control
switch 24, nozzle 26, air supply line 30, system line 32, water
inlet line 34, pressurization line 36, media line 38, blast line
40, junction 42, disconnect 44, system valve 46, pump pressure
regulator 48, flow valve 50, check valve 52, air filter 54,
pressure gauge 56, pressure relief 58, system control line 60a,
system control line 60b, pump control line 62, blast control line
64, pressure control line 66, and control valve 322. Blast air
controller 14 includes air pressure regulator 68 and blast air
regulator 70. Water pump 18 includes shuttle valve 72, and shuttle
valve 72 includes shuttle member 74.
[0061] Vapor blast system 300 is substantially similar to vapor
blast system 10 shown in FIG. 1, vapor blast system 100 shown in
FIG. 2, and vapor blast system 200 shown in FIG. 3, except control
valve 322 of vapor blast system 300 mechanically interacts with
water pump 18 to control the flow of pressurizing water to pressure
pot 20, similar to control valve 22c (FIG. 1).
[0062] Pressure control line 66 extends from system valve 46 to
control valve 322. Water pump 18 includes shuttle valve 72 that
includes a reciprocating shuttle member that directs the system air
received from pump control line 62 to power water pump 18. Control
valve 322 inhibits reciprocation of the shuttle member 74 of
shuttle valve 72 when in the closed state to prevent water pump 18
from pumping water to pressure pot 20. For example, control valve
322 can be configured to extend a pin into shuttle valve 72 to
mechanically inhibit reciprocation of shuttle member 74. With
control valve 322 in the open position, shuttle member 74 is free
to reciprocate and direct the flow of system air to power water
pump 18.
[0063] Control valve 322 is normally-open and shifts to the closed
state when system valve 46 is in the system-off state and is
directing the system air through pressure control line 66. Control
valve 322 returns to the open state when system valve 46 is in the
system-on state and is directing the system air to blast control
line 64.
[0064] Control valve 322 is controlled between the open state and
the closed state to control pressurization of pressure pot 20.
Actuating control valve 322 to the closed state deactivates water
pump 18. Deactivating water pump 18 prevents water pump 18 from
pumping water to pressure pot 20 through pressurization line 36,
thereby allowing the pressure in pressure pot 20 to drop. The
decreased pressure in pressure pot 20 is sufficiently low such that
the pressure does not drive the blast slurry downstream to blast
line 40 through media line 38. Pressure pot 20 remains at the
decreased pressure and the blast slurry remains in pressure pot 20
until control valve 322 shifts to the open state and water pump 18
pumps water to pressure pot 20.
[0065] Control valve 322 shifts to the open state when system valve
46 is in the system-on state and is directing the system air to
blast control line 64. In the open state, control valve 322 allows
shuttle member 74 to reciprocate to direct the system air within
water pump 18 to power water pump 18. Water pump 18 draws water
from water source 16 and pumps the water to pressure pot 20 through
pressurization line 36. The pumped water increases the pressure in
pressure pot 20, and the increased pressure drives the blast slurry
out of pressure pot 20 to media line 38, and downstream through
media line 38 to blast line 40.
[0066] Vapor blast system 300 includes logic, such as control logic
28 (FIG. 1), to prevent undesired accumulation of the blast slurry
in blast line 40. When system valve 46 shifts to the system-on
state, the logic ensures that blast air regulator 70 shifts to the
open state prior to control valve 322 shifting to the open state.
When system valve 46 shifts to the system-off state, the logic
ensures that control valve 322 shifts to the closed state prior to
blast air regulator 70 shifting to the closed state.
[0067] Vapor blast system 300 and control valve 322 provide
significant advantages.
[0068] Control valve 322 controls the flow of system air to water
pump 18 to control the flow of blast slurry out of pressure pot 20.
Control valve 322 deactivates water pump 18 by mechanically
deactivating water pump 18. Control valve 322 interfaces with only
the mechanical components of water pump 18 and is therefore not
subject to the wear generated by interacting with the blast media
in the blast slurry. Preventing wear to control valve reduces
maintenance and replacement costs and simplifies vapor blast system
300.
[0069] Although the present invention has been described with
reference to preferred embodiments, 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.
* * * * *