Valve construction for pressurized flow of abrasive granular material

A valve intended primarily for use on the end of a supply hose for directing and controlling a high velocity stream of an abrasive granular material against an object. The valve has a handle with a usual discharge nozzle mounted on one end thereof, with the granular material supply hose being connected to the other end of the handle. A lever is pivotally mounted on the handle and is movable between open and closed positions with respect to the nozzle. The lever has a hand-actuated inner end portion and a nozzle sealing outer end portion. A spring is mounted on the lever and biases the lever toward closed position. A resilient sealing member is mounted on the outer end of the lever and forms a seal completely external of the nozzle against the open discharge end of the nozzle when the lever is in closed position. Magnets may be mounted on the handle and inner end of the lever and are mutually engageable when the lever is in open position to assist an operator in overcoming the biasing effect of the spring.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The invention relates to valves, and in particular to a valve for use in 
directing and controlling a high velocity stream of abrasive granular 
material. More particularly, the invention relates to a valve for a 
pressure-fed sandblaster having external shut-off means on the nozzle 
portion of the valve for controlling the spray of high velocity granular 
material. 
2. Description of the Prior Art 
The use of high pressure air for discharging a stream of an abrasive 
granular material for removing paint and rust from objects, such as car 
bodies, metal parts, building exteriors and the like, has been practiced 
for numerous years, much of which is commonly referred to as sandblasting. 
In this procedure, silica sand, glass beads or other granular materials 
are mixed with a stream of high pressure air and discharged through a 
nozzle which is held either manually or mechanically for directing the 
stream of the abrasive particles against the object being treated. 
More recently, small portable pressure-fed blasters have been devised for 
smaller jobs than the heretofore large buildings, wherein a supply of 
compressed air is connected to a portable tank containing a predetermined 
amount of sand which is mixed with the pressure air stream. A manual valve 
is mounted on the end of a hose for turning on and shutting off the high 
velocity flow of granular material. A nozzle is incorporated in this valve 
for discharging the stream of abrasive particles and directing it against 
the object being cleaned with a sufficiently high velocity. 
These valves use a manually operated ball-type shut-off mechanism in which 
a metal shut-off ball is mounted internally within the valve body and 
controlled by an external rotatable handle. This arrangement 
satisfactorily stops and starts the flow of abrasive material through the 
nozzle. However, problems arise in the use of such valves in that, when 
the valve is not rotated to a fully open or fully closed position, the 
abrasive material will continue to flow throughout the valve and out of 
the nozzle. The abrasive material, upon flowing in a somewhat irregular 
path through the partly opened or closed ball valve, quickly wears away or 
damages the metal ball valve and even the valve body. Thus, in a 
relatively short period of time, the ball or valve body is destroyed if 
operated in such a partly open or closed position, requiring replacement 
of the entire valve. These prior valves also require the use of both hands 
for their operation, one hand for holding the valve and the other hand for 
rotating the control lever. 
An unsafe condition also is presented with these known manually operated 
hand-held valves since the valve remains open if dropped accidentally by a 
workman. The trailing hose and valve, due to the air pressure flowing 
therethrough, could whip about seriously injuring the operating or 
bystander or damaging equipment in the area since the valve remains in the 
open position until manually rotated to off position. 
Therefore, these existing vaves provide both safety and maintenance 
problems and increased cost to the users thereof. 
No valve construction for use with a high velocity stream of an abrasive 
granular material, of which I am aware, had eliminated the problems of 
repeated replacement and damage of the internal shut-off mechanism and the 
elimination of an unsafe condition if the valve is dropped during use, by 
a relatively simple external shut-off sealing member which returns 
automatically to a fully closed or shut-off position if not manually 
restrained in the open position. 
SUMMARY OF THE INVENTION 
Objectives of the invention include providing a valve construction for 
controlling and directing the flow of a high pressure stream of an 
abrasive granular material which has a completely external sealing member 
for stopping the flow of the material from the nozzle outlet opening, 
eliminating the heretofore premature wear of an internal shut-off valve 
control member; providing such a valve constuction in which the shut-off 
sealing member is mounted on a lever which is spring biased toward closed 
position, whereby the valve shuts off completely and automatically if 
accidentally dropped by a workman; providing such a valve construction in 
which magnets are mounted on the valve body and lever operating handle and 
are mutually engaged when the valve is in open position to assist an 
operator in overcoming the return bias of the spring to reduce fatigue on 
the operator; providing such a valve construction in which the external 
shut-off sealing member can be used with a usual nozzle of the type being 
used with the internal shut-off ball valve, thereby eliminating the need 
for special components and eliminating increased cost; providing such a 
valve construction in which the sealing member is an extremely inexpensive 
component, preferable formed of a resilient elastomer material, which if 
damaged by the high velocity stream of abrasive material, can be replaced 
quickly and conveniently by an operator for a fraction of the cost 
heretofore required to replace the entire internally operated valve body; 
providing such a valve construction in which the sealing member lever and 
its pivoting mounting mechanism can be molded easily and inexpensively of 
a synthetic plastic or similar type of material; providing such a valve 
mechanism which can be operated entirely by one hand freeing the 
operator's other hand for performing associated work during the cleaning 
operation; and providing such a valve construction which is relatively 
simple in construction, operation and use, which reduces maintenance 
problems and costs, which is sturdy and durable in use, which achieves the 
stated objectives in a simple, effective and inexpensive manner, and which 
solves provlems and satisfies needs existing in the art. 
These and other objectives and advantages may be obtained by the valve 
construction of the type for use in controlling the flow of an abrasive 
granular material, the general nature of which may be stated as including 
handle means having an outlet nozzle and a supply inlet opening 
communicating with said nozzle, the inlet opening being adapted to receive 
a quantity of an abrasive granular material under pressure, said nozzle 
terminating in a discharge outlet opening for directing a spray of the 
granular material against an object; lever means movably mounted on the 
handle means for movement between open and closed positions; spring means 
biasing the lever means toward closed position; and sealing means mounted 
on the lever means for movement with said lever means, said sealing means 
externally blocking the outlet opening of the nozzle when the lever means 
is in closed position to prevent flow of a granular material from the 
nozzle.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
The valve construction of the invention is indicated generally at 1, and is 
shown in FIG. 1 connected to a length of high pressure air hose 2. A tank 
3 is adapted to receive a predetermined quantity of an abrasive granular 
material, such as silica sand, glass beads, etc. This material is drawn 
into air hose 2 at a connector 4 formed at a junction with a second 
section of high pressure air hose 5. Hose 5 is connected to a source of 
air pressure, such as a compressor (not shown) and may have a control 
valve 6 mounted therein. The particular pressure-fed blaster equipment 
shown in FIG. 1 is merely one type of such equipment with which valve 1 
may be used, and is for illustrative purposes only and forms no part of 
the invention. 
Valve 1 is shown particularly in FIGS. 2-5, with FIGS. 3 and 5 illustrating 
valve 1 in closed (shut-off) and open positions, respectively. Valve 1 
includes a handle, indicated generally at 7, which is adapted to be 
gripped by an operator. Handle 7 includes a short section of preferably 
rigid pipe 8 having a resilient outer gripping sleeve 9 telescopically 
mounted thereon. Sleeve 9 may be formed with a plurality of finger 
receiving depressions 10. Pipe 8 is formed with a hollow interior or bore 
11 and terminates in a threaded inlet end 12 for connection to high 
pressure air hose 2 by a coupling 13. 
A nozzle, indicated generally at 15, is threadably connected to the outlet 
end of pipe 8 (FIG. 4) for discharging an abrasive granular material in a 
high velocity spray which enters inlet end opening 14 of pipe 8 through 
hose section 2. Nozzle 15 is of a usual construction and may be of the 
type presently used with the internal ball-type shut-off valve which is 
being eliminated by valve construction 1. 
Nozzle 15 includes a conical-shaped outer nose 16 having a bore 17 in which 
a ceramic nozzle tip 18 is telescopically mounted. A rubber bushing or 
O-ring 19 abuts the inlet end of ceramic tip 18 and is secured in nose 16 
by the forward end 20 of a threaded coupling, indicated generally at 21. 
Coupling 21 includes a pair of threaded ends 22 and 23 which may be of 
different size diameters, and which are threadably engaged with nozzle 
nose 16 and pipe 8, respectively. Nozzle tip 18 is formed with a hollow 
central bore 24, which terminates in a discharge outlet opening 25. 
In accordance with the invention, a lever indicated generally at 30, is 
pivotally mounted on handle 7 for movement between open and closed 
positions, shown in FIGS. 5 and 3, respectively. Lever 30 is pivotally 
mounted on handle 7 by a pivot assembly indicated generally at 31 (FIG. 
8). Lever 30 preferably is formed of an injection molded plastic or 
similar synthetic material and includes a gripping end rear portion 32 and 
a nozzle seal mounting front end portion 33. Lever ends 32 and 33 form an 
obtuse included angle therebetween, as can be seen in FIGS. 3 and 5. 
Lever end 33 terminates in a pair of spaced flanges 34 (FIGS. 6 and 7), 
which extend outwardly therefrom in a generally perpendicular transverse 
direction with respect to the longitudinal axis of handle 7. A nozzle 
sealing member 36 is mounted within a space 37 which is formed between 
flanges 34 and is adapted to abut the outer end of nozzle tip 18 and seal 
against outlet opening 25, as shown in FIG. 7 when lever 30 is in closed 
position. Sealing member 36 preferably is formed of a short section of a 
resilient hollow tubular material, such as various types of rubber or 
other elastomer and is telescopically mounted on shank 38 of a bolt 39 
between flanges 34. Bolt 39 extends through a pair of aligned holes formed 
in flanges 34 with bolt head 40 abutting one flange and nut 41 and 
associated washer 42 abutting the opposite flange (FIG. 6). 
Various configurations of sealing members 36 may be used with valve 1 and 
may be formed of various materials other than rubber. However, it has been 
found that the more resilient or softer the rubber used for member 36, the 
less harmful effect the abrasive stream of granular material has thereon 
when it contacts member 36 during movement of lever 30 between open and 
closed positions. Likewise, sealing member 36 need not have the tubular 
shape as shown since other configurations may be used to effectively block 
or seal external discharge opening 25 of nozzle tip 18 without departing 
from the concept of the invention. 
Pivot assembly 31 (FIG. 8) is formed by a collar 44 which has a pair of 
spaced upstanding projections 45, each projection being formed with an 
opening 46 for receiving and mounting a pivot bolt 47 therein. Collar 44 
is formed with a central opening 48 for reeceiving threaded end 22 of 
nozzle 15. Collar 44 is clamped against the inner end of nozzle nose 16 
and a hexagonal shaped flange 49 formed on nozzle 15 between threaded ends 
22 and 23 (FIG. 4). Threaded advancement of nozzle nose 16 along threaded 
end 22 securely clamps collar 44 against nozzle flange 49 for mounting 
pivot assembly 31 on handle 7. 
Pivot bolt 47 extends through an opening 50 formed in lever 30 at the 
junction of lever ends 32 and 33 for pivotally mounting lever 30 on bolt 
47. A coil spring 52 is telescopically mounted on bolt shank 51 between 
one of the collar projections 45 and a pair of washers 53. Spring 52 
terminates in a pair of projecting end portions 54 and 55 with end portion 
54 abutting collar 44 and end portion 55 abutting the underside surface 56 
of gripping end portion 32 of lever 30. 
In accordance with another of the main features of the invention, spring 52 
biases lever 30 toward the closed position of FIG. 3 and maintains sealing 
member 36 in sealing engagement with nozzle outlet opening 25 until lever 
30 is manually operated by gripping handle 7 and lever 30, whereupon lever 
end portion 32 is pivoted toward handle 7. 
Another feature of the invention is the mounting of a pair of mutually 
attractable magnets 60 and 61 on handle 7 and lever end portion 32, 
respectively, to assist in reducing the fatigue on an operator's hand when 
using valve 1 over an extended period of time. Magnets 60 and 61 are 
mounted on handle 7 and lever 30 by an adhesive or other attachment means 
and are positioned thereon to be engaged with each other, as shown in FIG. 
5, when lever 30 is moved to open position. The attractive force of 
magnets 60 and 61 attempts to maintain lever 30 is open position by 
overcoming the biasing effect of spring 52, which is biasing lever 30 
toward closed position in the opposite direction. 
The retaining or coupling force of magnets 60 and 61 is less than the 
biasing force of spring 52 to prevent lever 30 from remaining in open 
position upon release of the lever by an operator. Also, it is readily 
understood that only a single magnet 60 or 61 could be used with the 
opposite member being a metallic plate to achieve the desired magnetic 
retaining force. Likewise, other types of retaining latch means could be 
used instead of magnets to reduce the pressure exerted by spring 52 on an 
operator's hand without departing from the concept of the invention. 
The operation of valve 1 is easily seen and understood by an inspection of 
FIGS. 3, 5 and 7. An operator grips handle 7 and lever end portion 32 with 
one hand. Upon exertion of a gripping force on handle 7 and lever end 32, 
end 32 will move toward handle 7 pivoting lever end 33 away from nozzle 
tip 18 from the closed position of FIG. 3 to the open position of FIG. 5. 
A stream 62 of an abrasive granular material is ejected automatically 
under a relatively high pressure against an object to be cleaned thereby. 
The operator merely maintains lever end 32 pressed against handle 7, 
assisted by magnets 60 and 61, throughout the cleaning period. The 
operator merely releases his grip on lever 30, whereupon spring 52 
automatically pivots lever 30 from the open position of FIG. 5 to the 
closed position of FIG. 3. Sealing member 36 (FIG. 7) automatically and 
effectively blocks and seals nozzle discharge end opening 25 preventing 
further flow of abrasive stream 62. 
A typical type of portable pressure-fed sandblaster with which valve 1 may 
be used will have a maximum air pressure of 175 lbs/in.sup.2 with a nozzle 
velocity of 22 CFM, although other pressures and velocity may be used 
satisfactorily with valve 1. 
Valve construction 1 has a number of advantages not believed available in 
existing valve constructions for use in controlling the flow of a high 
pressure stream of an abrasive granular material. Sealing member 36 
completely blocks and seals discharge opening 25 of nozzle tip 18 
externally of nozzle 15. This external seal eliminates the undesirable 
wear of internal valve components, as in prior valve constructions, or the 
use of the valve in a partially open or closed position resulting in 
damage to the valve body by the nonlinear path required to be traveled by 
the stream of material. Furthermore, even should sealing member 36 become 
worn or damaged by the abrasive stream 62 during the repeated opening and 
closing of the valve, or even if valve 1 is operated incorrectly in a 
partially open position, sealing member 36 need only be replaced with a 
similar short section of tubing by removal of nut 41. Such replacement is 
performed at a fraction of the cost and time heretofore required for 
replacing the internal ball valve, and possibly the entire valve body as 
in prior valve constructions. Also, due to the biasing effect of spring 52 
and the method of operating valve 1, level 30 is less likely to be 
operated in a partially open or closed position causing damage to sealing 
member 36, as with prior valve cosntructions. 
Another important advantage of the valve construction 1 is the safety 
feature achieved by the spring biasing of lever 30 to ward closed 
position. Should valve 1 be dropped by an operator during use, or 
inadvertently laid down without moving the valve to a fully closed 
position, lever 30 will pivot automatically to closed position with 
sealing member 36 completely stopping the spray of granular material 62. 
This prevents any whipping action which could occur when a valve is left 
in an open position on the end of a length of high pressure air hose. 
Other advantages are the use of magnets 60 and 61 to reduce the fatigue 
exerted on an operator's hand during use of valve 1 caused by the biasing 
of spring 52 which could become tiring when used for long intervals of 
time. Also, valve 1 is held and operated by only one hand eliminating 
two-hand operation as with prior valve constructions. 
Valve 1 has a minimum number of moving parts and, except for lever 30 and 
collar 44 of pivot assembly 31, the remaining components of valve 1 are 
readily available parts which can be purchased at a relatively low cost. 
Lever 30 and collar 44 also may be molded of an inexpensive plastic or 
synthetic material. 
Although the above description and accompanying drawings describe and 
illustrate valve 1 as being intended for use primarily for a sandblaster 
or other pressure blaster application for use with an abrasive granular 
material, it is readily understood that valve 1 could be used for other 
applications for stopping the flow of a fluid, liquid or other materials 
which are being discharged from a nozzle opening under pressure, and the 
scope of the invention need not be limited to a sandblaster application. 
Accordingly, valve construction 1 is simplified, provides an effective, 
safe, inexpensive, durable and efficient device which achieves all the 
enumerated objectives, provides for eliminating difficulties encountered 
with prior devices, and solves problems and obtains new results in the 
art. 
In the foregoing description, certain terms have been used for brevity, 
clearness and understanding, but no unnecesary limitations are to be 
implied therefrom beyond the requirements of the prior art, because such 
terms are used for descriptive purposes herein and are intended to be 
broadly construed. 
Moreover, the description and illustration of the invention is by way of 
example, and the scope of the invention is not limited to the exact 
details shown or described. 
Having now described the features, discoveries and principles of the 
invention, the manner in which the valve construction is constructed and 
used, the characteristics of the new construction, and the advantageous, 
new and useful results obtained; the new and useful structures, devices, 
elements, arrangements, parts, and combinations are set forth in the 
appended claims.