U.S. patent number 3,625,404 [Application Number 04/829,206] was granted by the patent office on 1971-12-07 for apparatus and method for dispensing particulate material.
This patent grant is currently assigned to Ransburg Electro-Coating Corp.. Invention is credited to Richard O. Probst.
United States Patent |
3,625,404 |
Probst |
December 7, 1971 |
**Please see images for:
( Certificate of Correction ) ** |
APPARATUS AND METHOD FOR DISPENSING PARTICULATE MATERIAL
Abstract
An apparatus capable of dispensing particulate material and a
method for accomplishing the dispensing of the material. The
apparatus includes a fluid-activated means capable of causing
particulate material to be withdrawn from a reservoir at a rate
which is substantially proportional to the fluid flow rate in the
fluid-activated means. A means for dispensing the particulate
material toward an article to be coated is connected to the
fluid-activated means through a conduit. A fluid divider has an
inlet port connected to a source of compressed fluid. The fluid
divider also includes a plurality of outlet ports. One of the
outlet ports of the fluid divider is connected to the reservoir to
thereby provide the fluid flow which activates the fluid-activated
means. Another of the outlet ports of the fluid divider is
connected to the conduit to provide a fluid flow in the conduit
which assists in the movement of the particulate material in the
conduit toward the means which dispenses the material. The fluid
divider may be a device which includes a fluid-splitting member
which divides the fluid flow at the inlet port among the several
outlet ports. The sum of the fluid flows at the outlet ports of the
fluid divider is substantially proportional to the fluid flow at
the inlet port.
Inventors: |
Probst; Richard O.
(Indianapolis, IN) |
Assignee: |
Ransburg Electro-Coating Corp.
(Indianapolis, IN)
|
Family
ID: |
25253848 |
Appl.
No.: |
04/829,206 |
Filed: |
June 2, 1969 |
Current U.S.
Class: |
406/12;
137/625.14; 406/93 |
Current CPC
Class: |
B05B
7/1404 (20130101); B05B 7/1472 (20130101); B05B
12/08 (20130101); B05B 5/1683 (20130101); B05B
12/126 (20130101); Y10T 137/86525 (20150401) |
Current International
Class: |
B05B
12/08 (20060101); B05B 7/14 (20060101); B05B
5/00 (20060101); B05B 5/16 (20060101); B65g
069/06 () |
Field of
Search: |
;222/193,195,485,486
;239/15 ;137/625.14,625.12,625.33,625.5 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Tollberg; Stanley H.
Claims
I claim:
1. An apparatus capable of dispensing particulate material
comprising,
a bed containing particulate material,
a fluid-activated means capable of causing the particulate material
to be drawn from the bed at a rate substantially proportional to
the fluid flow rate in the fluid-activated means,
means for dispensing the particulate material drawn from the
bed,
a conduit connecting the fluid-activated means to the means for
dispensing the particulate material, and
a fluid divider having an inlet port connected to a source of fluid
under an elevated pressure and having a plurality of outlet ports,
one of the outlet ports connected to the fluid-activated means
providing the fluid flow in the fluid-activated means, another of
the outlet ports connected to the conduit to provide a fluid flow
in the conduit which assists in the movement of the particulate
material in the conduit toward the means for dispensing the
particulate material, and the fluid divider including means
activated by a fluid control signal thereby regulating the flow of
fluid from at least one of the outlet ports of the fluid divider so
that the sum of the fluid flows at the outlet ports of the fluid
divider is substantially proportional to the fluid flow at the
inlet port of the fluid divider.
2. The apparatus as claimed in claim 1 wherein the fluid divider
includes a plurality of fluid regulators capable of adjustably
regulating the fluid flow rate supplied to the fluid-activated
means and to the other outlet.
3. The apparatus as claimed in claim 2 wherein at least one of the
fluid regulators is activated by the control signal to thereby
adjustably regulate the fluid flow rate.
4. The apparatus as claimed in claim 1, wherein the particulate
material includes a powdery substance capable of being
electrostatically charged and wherein the dispensing means includes
an electrostatic spray gun capable of electrostatically charging
the powdery substance.
5. The apparatus as claimed in claim 4, wherein the fluid-activated
means includes a fluidized bed containing the powdery substance and
a fluid-actuated pump which draws the powdery substances from the
fluidized bed at a rate proportional to the fluid flow rate through
the pump.
6. A method for dispensing particulate material comprising
dividing a fluid flow into a plurality of fluid flow outputs by
means of a fluid divider activated by a fluid control signal
thereby regulating the flow of fluid from the fluid divider,
supplying one of the fluid flow outputs to a fluid-actuated means
capable of drawing particulate material from a bed at a rate
proportional to the fluid flow rate in the fluid-activated means,
and
combining the fluid flow rates from the fluid-activated means and
from another of the fluid flow outputs in a conduit connected to a
dispensing means whereby the fluid flow rate supplied to the
dispensing means is substantially constant.
7. In an apparatus for dispensing particulate material, means for
dividing a gaseous input into a plurality of gaseous outputs the
sum of which is substantially equal to the gaseous input to the
means, one of the gaseous outputs is connected to a particulate
material-dispensing means and other of the gaseous outputs is
connected to the dispensing means through a source of particulate
material, the dispensing means having a substantially constant
gaseous flow therethrough that is substantially independent of the
particulate material dispensed whereby accumulation of particulate
material in the apparatus is discouraged, the means for dividing
the gaseous flow comprising
a body including an inlet port and a plurality of outlet ports
connected by a bore, the inlet port adapted to be connected to a
gaseous medium source, the outlet ports connected to the
particulate material dispensing means, and
a displaceable gaseous flow-splitting member in the bore of the
body adjacent the outlet ports, the gaseous flow-splitting member
displaceable toward one of the outlet ports and away from the
remaining outlet ports thereby providing gaseous outputs the sum of
which is substantially equal to the gaseous input.
8. The means as claimed in claim 7, wherein the gaseous
flow-splitting member includes surfaces which encourage fluid flow
toward the outlet ports.
9. The means as claimed in claim 8, wherein the gaseous
fluid-splitting member includes a plurality of frustoconical
members having adjacent bases.
10. The means as claimed in claim 9, wherein each of the
frustoconical members have substantially the same dimensions and
substantially the same taper angle and each of the outlet ports
have substantially equal area openings adjacent the frustoconical
members.
11. The means as claimed in claim 10, wherein the outlet ports are
two outlet ports spaced from each other and the openings thereof
are substantially coaxial.
12. The means as claimed in claim 11, wherein the axis of the inlet
port is substantially perpendicular to the axis of the outlet
ports.
13. An apparatus for dispensing particulate material comprising
a bed containing particulate material,
a fluid-activated means in the bed for causing the particulate
material to be drawn from the bed at a rate substantially
proportional to the fluid flow rate in the fluid-activated
means,
means for dispensing the particulate material drawn from the
bed,
a conduit connecting the fluid-activated means to the means for
dispensing the particulate material, and
a fluid divider including an inlet port adapted to be connected to
a fluid under pressure, at least two outlet ports and a fluid
impedance means adjacent the outlet ports, one of the outlet ports
connected to the fluid-activated means so as to provide fluid flow
to the fluid-activated means from the fluid source, another of the
outlet ports connected to the conduit so as to provide a fluid flow
in the conduit assisting in the movement of the particulate
material in the conduit toward the means for dispensing the
particulate material, the fluid impedance means displaceable toward
one of the outlet ports and away from the other outlet port for
predeterminately dividing the fluid flow at the inlet port between
the outlet ports whereby the fluid flow rate to the fluid activated
is adjustable so as to withdraw variable amounts of particulate
material from the bed without effecting the flow rate of fluid in
the conduit
14. The apparatus as claimed in claim 13, wherein the fluid flow
rate to the dispensing means is substantially constant and
independent of the adjustment of the fluid divider.
15. The apparatus as claimed in claim 13 wherein the particulate
material includes a powdery substance capable of being
electrostatically charged and wherein the dispensing means includes
an electrostatic spray gun capable of electrostatically charging
the powdery substance.
16. The apparatus as claimed in claim 15, wherein the
fluid-activated means includes a fluidized bed containing the
powdery substance and a fluid-actuated pump which draws the powdery
substance from the fluidized bed at a rate proportional to the
fluid flow rate through the pump.
Description
The present invention relates to a dispensing apparatus and, more
particularly, to an apparatus capable of dispensing particulate
material and to a fluid-dividing device which may be used as a
component part of the apparatus. In addition, the present invention
relates to a method for dispensing the particulate material.
Generally, a particulate material-dispensing apparatus is connected
to a source of compressed air which serves as the means for
activating a suitable air-activated pump. The pump generally
includes an open-throated venturi tube seated in a reservoir
containing particulate material. As the compressed air flows
through the open-throated venturi tube, particulate material is
caused to be drawn from the reservoir at a rate proportional to the
rate of flow of the air through the venturi tube. The particulate
material is entrained in the air and delivered by the flowing air
to a dispensing device such as a handgun. The handgun causes the
particulate material to be directed toward a surface of an article
to be coated with the material.
The movement or rate of flow of the entraining air emitted at the
nozzle of the dispensing device should be sufficiently high so as
to achieve, among other things, the desired spray pattern, the
desired distribution of the particulate material within the spray
pattern and a uniform layer of the material on the article.
Usually, satisfactory coating of the article with the particulate
material is accomplished by using a hose having an internal
diameter of about 3/8 of an inch and using an airflow thru the
air-activated pump of from about 1.5 to about 2.5 standard cubic
feet per minute (s.c.f.m.).
Generally, the hose has a substantially constant internal diameter
so as to assist in providing the proper airflow rate necessary to
transport the entrained material and to minimize the possibility of
providing sites at which the particulate material may accumulate.
The hose is generally satisfactory for its intended purpose as long
as the airflow rate within the hose remains above a velocity which
discourages accumulation of the particulate material along the
sidewall of the hose. However, if the flow rate of the material
through the hose drops below a minimum velocity due to any one of
several factors such as a reduction in airflow below about 1.5
s.c.f.m. in a hose having a 3/8 inch internal diameter, the
particulate material exhibits a tendency to accumulate along the
sidewall of the hose connected between the reservoir and the
dispensing device. During the interval of time the particulate
material is accumulating along the sidewalls of the hose, the
amount of material being emitted per unit of time by the dispensing
device may be below that which is necessary to coat the article
within the required time interval with a uniform coating of
material having a desired thickness.
When a sufficient amount of the particulate material has
accumulated along the sidewall of the hose, the air pressure behind
the accumulated material may build up sufficiently to provide a
force adequate to cause the movement of the accumulated mass of
particulate material through the hose and out of the nozzle of the
dispensing means. Upon release of the accumulated mass of
particulate material, the material again starts to accumulate along
the sidewall of the hose until sufficient force is provided to move
the mass of accumulated particulate material through and out of the
hose. The release of the mass of accumulated material may be
referred to as "puffing." The accumulation and release of
accumulated particulate material is cyclical. As a result of
substantially instantaneous release of the accumulated mass of
particulate material from the dispensing means, undesirable amounts
of the material may be deposited onto the article. In addition,
"puffing" can cause localized heavy coating of material on the
article and thus the coating tends to be undesirably
nonuniform.
A reduction in the magnitude of the "puffing" problem may be
realized by using a hose having a smaller internal diameter when
the flow rate of the air is reduced. However, an operator may
experience an inconvenience by "shutting down" the operation of the
equipment in order to remove the hose and substitute for it a hose
having a smaller internal diameter.
Therefore, it is an object of the present invention to provide a
means and a method which overcome the above-stated problems.
Another object of the present invention is to provide an apparatus
capable of dispensing particulate material entrained in a fluid
which eliminates the necessity for changing from one hose diameter
to a different hose diameter as the flow rate of the material
through the hose is altered.
A further object of the present invention is to provide an
apparatus capable of dispensing particulate material entrained in a
fluid, the fluid having a substantially uniform flow rate at the
point where the material is dispensed from the apparatus.
Another object of the present invention is to provide an apparatus
capable of dispensing variable amounts of particulate material
entrained in a gaseous medium, the gaseous medium having a
substantially uniform flow rate at the point where the material is
dispensed from the apparatus.
Yet another object of the present invention is to provide an
apparatus for dispensing particulate material which is capable of
depositing a substantially uniform layer of the material onto an
article which may be passed by the dispensing device at a variable
rate of speed.
Yet still another object of the present invention is to provide a
particulate-dispensing apparatus including a fluid divider which
assists in the movement of the material in a conduit towards a
means for dispensing the material.
A further object of the present invention is to provide an
apparatus capable of dispensing particulate material which is
economical to manufacture.
Another object of the present invention is to provide means for
dividing a fluid flow input into a plurality of fluid flow outputs,
the sum of the fluid flow outputs of the means being substantially
equal to the fluid flow input to the means.
A further object of the present invention is to provide a means
having a fluid flow input and a plurality of fluid flow outputs, a
fluid flow input to the means resulting in at least one fluid
output.
A further object of the present invention is to provide a method
for transporting particulate material to a particulate
material-dispensing device wherein the fluid flow rate at the
dispensing device is substantially constant with variable amounts
of particulate material entrained in the fluid flow.
With the aforementioned objects enumerated, other objects will be
apparent from reading the following description and the appended
claims.
In the drawings:
FIG. 1 is a schematic view of the present invention;
FIG. 2 is a partial cross-sectional view of a means for dividing a
fluid flow input into a plurality of fluid flow outputs;
FIG. 3 is a partial cross-sectional view of an embodiment of the
means for dividing the fluid flow into a plurality of fluid flow
outputs; and
FIG. 4 is a schematic view of an embodiment of the present
invention.
Generally speaking, the present invention relates to a particulate
material-dispensing apparatus and method which substantially
eliminates "puffing" of the material and to a means used as a
component part of the apparatus which divides a fluid flow input
into a plurality of fluid flow outputs.
The apparatus is capable of dispensing variable amounts of
particulate material entrained in a fluid medium wherein the fluid
medium has a substantially uniform flow rate under substantially
all conditions at the point in the apparatus where the material is
dispensed. The apparatus includes a fluid-activated means capable
of causing the particulate material to be drawn from a particulate
material reservoir at a rate substantially proportional to the
fluid flow rate in the fluid-activated means. A conduit is used to
connect the reservoir to a device which dispenses the particulate
material. The fluid divider of the apparatus has an inlet port
connected to a source of compressed fluid. The fluid divider
includes at least one outlet port connected to the fluid-activated
means so as to provide a fluid flow in the fluid-activated means
and at least one other outlet port connected to the conduit so as
to provide a fluid flow in the conduit which assists in the
movement of the fluid-entrained particulate material toward the
means which dispenses the material. The sum of the fluid flows at
the outputs of the fluid divider is substantially equal to the
fluid flow at the input of the fluid divider thereby providing a
fluid flow rate in the conduit between the fluid-activated means
and the dispensing means which is substantially uniform and a fluid
flow rate in the fluid-activated means which may be varied so as to
withdraw variable amounts of the material from the reservoir
without harmfully effecting the flow rate of the fluid through the
conduit.
The method of the present invention generally relates to dividing a
fluid flow input into a plurality of fluid flow outputs, which
outputs are substantially equal in total to the input. The divided
fluid is used to provide a fluid flow rate at the dispensing device
which is substantially uniform and which is capable of providing
variable but controlled amounts of particulate material entrained
in the fluid flow.
Referring now to FIG. 1 of the drawing, the apparatus of the
present invention, capable of dispensing a particulate material, is
indicated by the reference numeral 10. The apparatus 10 includes
means 11 which divides a fluid flow input into a plurality of fluid
flow outputs, a fluidized bed 12 which includes a reservoir 27 for
particulate material 13 and includes a suitable fluid activated
pump 14 which draws the material 13 from the bed 12, and a
dispensing device 15 which dispenses the material 13 toward an
article (not shown) to be coated with the material 13.
The input port of fluid divider 11 may be connected to any suitable
source 16 of compressed fluid through a suitable fluid conduit 19.
The source 16 of compressed fluid may include suitable
pressure-regulating devices 17 and 17' which are intended to
compensate for variations in the fluid flow rate supplied by a
suitable fluid compressor 18. The fluid supplied by the fluid
source 16 may be any suitable medium which is capable of being
easily compressed and which is capable of entraining the
particulate material 13. A suitable fluid is a gas such as air and
the like.
The fluid divider 11 may include any suitable means which is
capable of dividing the compressed fluid supplied thereto by the
source 16 into at least two fluid outputs. The sum of the fluid
flow rate at the outputs of the fluid divider 11 is substantially
equal to the fluid flow rate at the input to the fluid divider. In
addition, the fluid divider 11 may include a means (not shown in
FIG. 1) which is capable of varying or adjusting the flow rate of
compressed air from each of the output ports. The structure of the
fluid divider 11 and its operation will be discussed herein
later.
The fluid-activated pump 14 of the fluidized bed 12 is connected to
one of the outlet ports of the fluid divider 11 by way of conduit
21. The fluidized bed 12 further includes a particulate material
reservoir 27 having air chamber 29 which may be equipped with an
air-distributing device 24, an agitator 25 and a membrane 26 which
permits fluidizing air to pass upwardly therethrough and which
prevents the particulate material 13 from passing downwardly
therethrough. The air-distributing device 24 may be connected to
the pressure-regulating device 17' of source 16 of compressed fluid
by any suitable conduit such as hose 28. The air-distributing
device 24, the membrane 26 and the agitator 25 cooperate to
fluidize the particulate material 13. The membrane 26 supports the
fluidized particulate material 13 and maintains the material
separate from the air chamber 29. The fluid-activated pump 14 may
traverse the length of the bed 12 above the air chamber 29 and in
the fluidized particulated material 13. The fluid-activated means
14 may include an open-throated venturi tube (not shown). Although
the opening 23 cooperatively associated with the venturi tube may
be facing upwardly as illustrated in FIG. 1, it is understood that
the opening cooperatively associated with the venturi tube may be
faced to a side of the fluidized bed or faced down as desired. The
movement of air from the source 16 through the open-throated
venturi tube causes the fluidized particulate material 13 to be
drawn into the open-throated venturi tube. In lieu of the agitator
25, the fluidized bed 12 may be equipped with a vibrating member
(not shown). The vibrating member tends to provide a uniform
distribution of particulate material 13 to the open-throated
venturi tube.
A suitable conduit such as a hose 22 may be used to carry the
particulate material 13 from the open-throated venturi tube of the
fluid pump 14 to dispensing device 15.
The dispensing device 15 may be any suitable electrostatic
dispensing device such as a handgun capable of emitting and
imparting an electrostatic charge to the particulate material 13. A
suitable dispensing device 15 is an electrostatic powder dispensing
handgun carrying the nomenclature Assembly No. 322/8446 sold by the
Ransburg Electro-Coating Corp. An electrical power supply 80 is
connected to the electrostatic handgun and should be capable of
supplying up to about 90,000 volts DC at a current of up to about
200 microamperes to the hand gun. A suitable power supply is Power
Supply Assembly No. 231/8910 sold by the Ransburg Electro-Coating
Corp.
Another outlet port of the fluid divider 11 is connected to the
conduit 22 at a location downstream from the outlet orifice of the
fluid-activated pump 14 by means of conduit 20. The flow rate of
air through conduit 20 to the conduit 22 assists in the movement of
particulate material 13 in conduit 22 toward the dispensing device
15. It is seen that a portion of compressed air emitted by source
16 is diverted from the fluid-activated pump 14 to a location which
is between the dispensing device 15 and the pump 14. Generally, the
airflow rate in the conduit 22 from the point where the conduit 20
is connected to the conduit 22 to the dispensing device 15 is
substantially constant and equal to the sum of the airflow rates of
the pump 14 and the conduit 20. However, it is to be understood
that during the operation of the fluid-activated pump 14, the
venturi tube may cause additional air to be drawn thereinto,
thereby increasing the airflow rate in conduit 22 slightly above
the sum of the airflow rates at the outlet ports of the fluid
divider 11.
The present invention contemplates varying or adjusting the flow
rate of air through the venturi tube as desired to thereby vary the
amount of particulate material 13 withdrawn from bed 12 without
materially altering the airflow in conduit 22. Therefore, large or
small quantities of the particulate material 13 may be withdrawn
per unit of time from bed 12 without materially altering the total
fluid flow rate through conduit 22. It is seen that the airflow
rate in conduit 22 is substantially constant under nearly all
conditions thereby obviating the necessity for disconnecting
conduit 22 from the fluid-activated pump 14 and the dispensing
means 15 to alter the diameter of the conduit 22 in an attempt to
minimize the possibility of particulate material 13 agglomerating
or accumulating within conduit 22 to thereby reduce the possibility
of "puffing" of the material 13.
The point at which the hose 20 joins the hose 22 should be as close
to the outlet orifice of the fluid-activated means 14 as is
physically possible. So locating the junction point minimizes the
possibility of the particulate material 13 accumulating at a site
between the outlet orifice of the fluid-activated means and the
point at which hose 20 joins hose 22.
The particulate material 13 may be any dry, powdery substance which
is capable of being fluidized, which is capable of being entrained
in a fluid medium such as air and which is capable of accepting an
electrostatic charge. Suitable powders are thermoplastic powders
such as cellulose acetate butyrate, chlorinated polyether,
polyester, polyethylene, polypropylene, polyvinyl chloride,
polytetrafluoroethylene and the like; thermosetting resins such as
epoxy and the like; and other powdery substances such as commercial
talc, flour, glass, zinc stearate, starch, vitreous enamel and the
like.
Referring now to FIG. 2 of the drawing, the fluid divider of the
present invention is indicated by the reference number 11. As
discussed hereinbefore, the fluid divider 11 provides a means for
dividing the fluid supplied thereto by the source 16 of compressed
air. The fluid divider 11 includes a hollow, generally cylindrical
housing 41 having at least one inlet port 51 and at least two
outlet ports 52 and 53. The housing 41 may be fabricated from any
suitable material which provides good wear and is available at
reasonable cost. Suitable materials from which the housing 41 may
be fabricated are brass, aluminum, stainless steel, reinforced
plastic and the like. Of the several materials from which the
housing 41 may be fabricated aluminum is the preferred metallic
material.
The diameter of the inlet port 51 of the housing 11 and the
diameters of the outlet ports 52 and 53 are illustrated in the
drawing as being substantially the same thereby providing
substantially equal-area inlet and outlet ports. It is thought that
the diameter of any one or all the ports need not be substantially
the same. In addition, it is recognized that the housing may have a
configuration other than the configuration illustrated in FIG. 2.
For example, the housing 11 may have a "U" shaped configuration,
"T" shaped configuration and the like.
As shown in FIG. 2 a displaceable, flow-splitting member 46 is
located adjacent the inlet port 51 and between the outlet ports 52
and 53. The flow-splitting member 46 may include base-to-base
coupled frustoconical-shaped members 47 and 48. Each of the members
47 and 48 possess such a shape and diameter so as to engage or
disengage with chamfers 43 and 44 respectively thereby encouraging,
as the case may be, the airflow from the inlet port 51 to outlet
port 52 or to outlet port 53. It is noted that the fluid divider 11
allows fluid to flow from at least one of the outlet ports under
all operating conditions. For example, substantially all of the
compressed air present at inlet port 51 will flow through outlet
port 52 if the frustoconical shaped member 48 is engaged with
chamfer 44 so as to discourage compressed airflow through outlet
port 53. The flow-splitting member 46 should be fabricated from a
material similar to the material from which the housing 41 is
fabricated to minimize the occurrence of galvanic corrosion.
The housing of the fluid divider 11 may include seats 43 and 44
provided in the housing 41. The seats 43 and 44 may be chamfered at
an angle greater than or less than the angle of the frustoconical
member cooperatively associated therewith. It should be seen that
it is not necessary for either of the frustoconical members 47 and
48 to tightly seal with their respective chamfers 43 and 44. It is
thought that it is only necessary that the frustoconical members
and the chamfers cooperate in such a manner so aS to prevent a
substantial flow of compressed air therebetween. However, it is
recognized that if an airtight seal is desirable, a suitable seal
may be provided between the frustoconical member and its
cooperatively associated chamfer, if desired.
Displacement of the frustoconical members 47 and 48 of the
flow-splitting member 46 may be accomplished by any number of
different techniques. One technique of displacing the member 46 is
by rotating shaft 49 connected to the flow splitting member 46 by
rotating knurled knob 50 so as to turn shaft 49 into or out of
aperture 54 formed in the housing 41. It is seen that displacement
of shaft 49 causes longitudinal displacement of the flow-splitting
member 46. Longitudinal displacement of the flow-splitting member
46 causes the air flow at the inlet port 51 to be diverted to
outlet ports 52 and 53 or only to outlet port 52 or only to outlet
port 53 depending on the location of the transverse axis of the
fluid flow-splitting member 46 with respect to the axis of the
inlet port 51. Positioning the frustoconical flow-splitting member
46 within the bore 55 of the housing 41 as shown in FIG. 2, causes
a reduced amount of compressed air to flow out of outlet port 53 as
compared with the amount of compressed air flowing out of outlet
port 52. Displacement of the flow-splitting member 46 to a position
where the transverse axis thereof substantially coincides with the
axis of the input orifice 51, results in a condition where the
amount of airflow rate from both outlet ports 52 and 53 are
substantially equal assuming that each of the outlet ports have
substantially equal-area outlets. If the transverse axis of the
flow-splitting member 46 is displaced slightly from the axis of the
input port 51 toward the outlet port 52, the airflow ate at outlet
port 53 should be greater than the airflow rate at outlet port 52
assuming, as shown in FIG. 2, that the outlet ports 52 and 53 are
of equal-area. The airflow through outlet port 53 is greater than
the airflow through outlet port 52 since impedance to airflow
through port 52 is greater than the impedance to airflow through
port 53. If the flow-splitting member 46 is displaced to a position
where the sidewall of the frustoconical member 47 engages with the
chamfer 43 formed in the housing 41, the impedance to the airflow
through port 52 is nearly infinite and, therefore, substantially
all of the compressed air will flow from inlet port 51 to outlet
port 53. Displacement of the transverse axis of the flow-splitting
member 46 to the right of the axis of the inlet orifice 51 results
in more compressed air flowing through outlet port 52 than through
outlet port 53. Displacement of the frustoconical member 48 of the
flow-splitting member 46 to a position of engagement with the
chamfer 44 of the housing 41 encourages substantially all of the
compressed air flowing from the source of compressed air 16 to flow
from outlet port 52.
An initial adjustment of each of the frustoconical members 47 and
48 with respect to its cooperatively associated chamfer may be
desirable so that the cooperative relationship between the
frustoconical member and its chamfer provides the desired
restriction for any given position of the frustoconical member with
respect to its cooperatively associated chamfer. To accomplish the
adjustment, frustoconical member 48 may be rotated independently of
member 47 to thereby longitudinally displace member 48 with respect
to member 47 until the desired relationship between the member 48
and its cooperatively associated chamfer 44 is achieved. Member 47
and chamfer 43 would have its cooperative relationship established
by turning shaft 49 into or out of the aperture 54 prior to the
adjustment of member 48 with respect to its cooperatively
associated chamfer. It is understood that the position of member 47
with respect to chamfer 43 should remain unaltered during the
initial positioning of member 48 with respect to their
cooperatively associated chamfers, the members will move together
by rotating shaft 49.
The configuration of one or each of the members 47 and 48 of the
flow-splitting member 46 may be shaped different from the shape
illustrated in FIG. 2. For example, the member 46 and/or the member
47 may have a convexed side configuration, a concaved side
configuration and the like in lieu of the side configuration
illustrated. The chamfers 43 and 44 provided in the housing 41 may
be similarily altered so as to fit with the members 46 and 47 when
the members engage therewith.
With the structural disclosure in mind and by continued reference
to FIGS. 1 and 2 of the drawing, the following analysis of the
operation of the present invention will further serve to amplify
the novelty of the present invention.
Connecting the source 16 of compressed air to the inlet port 51 of
the fluid divider 11 encourages compressed air to flow from the
source 16 through the inlet port 51 to the outlet ports 52 and 53
of the fluid divider. Assuming that the flow-splitting member 46
has its transverse axis substantially coincident with the axis of
the inlet orifice 51, the impedance presented to the airflow to
each port is substantially equal, therefore, the airflow rate
through outlet port 52 and outlet port 53 is substantially equal.
About one-half of the compressed air from source 16 flows to
fluid-activated pump 14 so as to draw the particulate material 13
through the open-throated venturi tube 29 and cause it to flow
entrained in air into conduit 22. The rate at which the material 13
is drawn from the fluidized bed 12 by the fluid-activated pump 14
is proportional to the flow rate of the compressed air through the
venturi tube of the fluid-activated pump. The remainder of the
compressed air is caused to flow directly to hose 22. Hose 22 is
downstream from the fluid-activated pump 14. It should be seen,
however, that substantially all of the compressed air supplied by
the source 16 to the apparatus 10 is transferred to dispensing
device 15 through hose 22.
An operator may vary the amount of material 13 drawn from the
fluidized bed 12 by directing greater or lesser amounts of airflow
rates through the fluid-activated pump 14. The airflow rate
delivered to the fluid-activated pump 14 may be varied by varying
the position of the flow-splitting member 46 of flow divider 11
with respect to the outlet ports 52 and 53. For example, if a
greater amount of particulate material 13 is to be drawn from the
fluidized bed 12 and deposited onto an article, a greater portion
of the compressed air is caused to flow to the pump 14, that is the
airflow rate to the pump 14 is increased, and a lesser amount of
compressed air is shunted to the hose 22, that is the airflow rate
to the hose 22 through line 20 is decreased. If the amount of
particulate material 13 to be deposited on the article is required
to be less, the amount of compressed air caused to flow to the
fluid-activated pump 14 is reduced thereby reducing the amount of
particulate material 13 drawn from the fluidized bed 12; however,
it is seen the flow rate of the compressed air in hose 22 remains
substantially independent of variations in the flow rate at pump
14.
The present invention substantially reduces the possibility of
accumulation of the particulate material 13 within the hose 22
since the airflow rate within hose 22 is above a minimum flow rate
regardless of the amount of particulate material 13 drawn from the
fluidized bed 12 by the fluid-activated pump 14. If a higher
dispensing rate of particulate material 13 is desired, the
flow-splitting member may be moved to a position whereby the outlet
port 52 connected to the fluid-activated pump 14 is supplied with
an increased flow rate of air. The increased flow rate of air
through the venturi tube causes a greater amount of particulate
material 13 to be drawn from the fluidized bed 12; however, the
airflow rate within substantially the entire hose 22 remains
substantially constant thereby significantly reducing the
possibility of "puffing" of the particulate material 13 as it is
emitted by the dispensing device 15. If a lesser amount of
particulate material 13 is desired to be dispensed by device 15,
the flow-splitting member is moved to a position so that the
airflow rate through the venturi tube of the fluid activated pump
14 is reduced so as to draw less particulate material 13 from the
fluidized bed 12 and so that the airflow rate through the hose 20
is increased. It should be noted, however, that the amount of
airflow rate within hose 22, downstream from the fluid-activated
pump 14, remains substantially constant thereby minimizing the
possibility of "puffing" of the particulate material 13 as it is
delivered to the article to be coated.
Referring now to FIG. 3 of the drawing, an embodiment of the fluid
divider of the present invention is indicated by the reference
number 81. As discussed hereinbefore, the fluid divider provides a
means for dividing the fluid supplied thereto by the source of
compressed air such as source 16. The fluid divider 81 includes a
hollow, generally square housing 82 made up of housing half 101 and
housing half 102 fixedly retained together by any suitable coupling
means (not shown) such as bolts and the like. The housing 82 may be
fabricated from any suitable material which provides good wear and
is available at reasonable cost. Suitable materials from which the
housing 82 may be fabricated are brass, aluminum, stainless steel,
reinforced plastic and the like. Of the several materials from
which the housing 41 may be fabricated aluminum is the preferred
metallic material.
The housing half 102 includes at least one inlet port 83 and at
least two outlet ports 84 and 85. The diameter of the inlet port 83
of the housing 82 and the diameters of the outlet ports 84 and 85
are illustrated in the drawing as being substantially the same
thereby providing substantially equal-area inlet and outlet ports.
It is thought that the diameter of any one or all the ports need
not be substantially the same.
A displaceable, flow-splitting member 86 is located adjacent the
inlet port 83 and between the outlet ports 84 and 85. The
flow-splitting member 86 may include base-to-base coupled
frustoconical-shaped members 87 and 88. It should be recognized
that members 87 and 88 may have a shape other than frustoconical
such as conical and the like. Each of the members 87 and 88 possess
such as shape and diameter so as to engage or disengage with
chamfers 89 and 90 respectively thereby encouraging or
discouraging, as the case may be, the airflow from the inlet port
83 to outlet port 84 or to outlet port 85. It is noted that the
fluid divider 81 allows fluid to flow from at least one of the
outlet ports under all operating conditions. For example,
substantially all of the compressed air present at inlet port 83
will flow through outlet port 85 if the frustoconical-shaped member
87 is engaged with chamfer 89, as illustrated in FIG. 3, so as to
discourage compressed airflow through outlet port 84. The
flow-splitting member 86 should be fabricated from a material
similar to the material from which the housing 82 is fabricated to
minimize the occurrence of galvanic corrosion.
The housing 82 of the fluid divider 81 may include seats 89 and 90.
The seats 89 and 90 may be chamfered at an angle greater than or
less than the angle of the frustoconical member cooperatively
associated therewith. It should be seen that it is not necessary
for either of the frustoconical members 87 and 88 to tightly seal
with their respective chamfers 89 and 90. It is thought that it is
only necessary that the frustoconical members and the chamfers
cooperate in such a manner so as to prevent a substantial flow of
compressed air therebetween. However, it is recognized that if an
airtight seal is desirable, a suitable seal may be provided between
the frustoconical member and its cooperatively associated chamfer,
if desired.
Displacement of the frustoconical members 87 and 88 of the
flow-splitting member 86 may be accomplished by any number of
different techniques. One technique of displacing the member 86 may
be accomplished by rotating shaft 91 connected to the
flow-splitting member 86 through threaded block 92 and pin 93,
carried by block 92 and fixedly connected to flow-splitting member
86, by rotating knurled knob 94 so as to turn shaft 91 in recess 95
formed in the housing 82. Shaft 91 and block 92 are carried in
housing half 101. It is seen that rotating shaft 91 causes
longitudinal displacement of block 92 and displacement of pin 93
thereby causing longitudinal displacement of the flow-splitting
member 86. Longitudinal displacement of the flow-splitting member
86 causes the airflow at the inlet port 83 to be diverted to outlet
ports 84 and 85 or only to outlet port 83 or only to outlet port 84
depending on the location of the transverse axis of the fluid
flow-splitting member 86 with respect to the axis of the inlet port
83. Positioning the frustoconical flow-splitting member 86 within
the bore 100 of the housing 82 as shown in FIG. 3, discourages
compressed air from flowing out of the outlet port 84 and
encourages substantially all of the compressed air to flow out of
outlet port 85. Displacement of the flow-splitting member 86 to a
position where the transverse axis thereof substantially coincides
with the axis of the input orifice 83, results in a condition where
the amount of airflow rate from both outlet ports 84 and 85 are
substantially equal assuming that each of the outlet ports have
substantially equal-area outlets. If the transverse axis of the
flow-splitting member 86 is displaced slightly from the axis of the
input port 83 toward the outlet port 85, the airflow rate at outlet
port 84 should be greater than the airflow rate at outlet port 85
assuming, as shown in FIG. 3, that the outlet port 84 and 85 are of
equal-area. The airflow through outlet port 84 is greater than the
airflow through outlet port 85 since impedance to airflow through
port 84 is greater than the impedance to airflow through port 85.
If the flow-splitting member 86 is displaced to a position where
the sidewall of the frustoconical member 88 engages with the
chamfer 90, the impedance to the airflow through port 85 is nearly
infinite and, therefore, substantially all of the compressed air
will flow from inlet port 83 to outlet port 84.
The threaded block 92 may be cylindrical in cross section. The
recess 95 in which the threaded block 92 is slidably displaced
should have the same general configuration as the peripheral
contour of the block to thereby facilitate displacement of the
block therein. It is seen that the axial aperture 96 of the block
92 is threaded so as to mate with the threads formed on the shaft
91.
Rotational displacement of shaft 91 does not result in longitudinal
displacement thereof but rotational displacement of the shaft does
result in longitudinal displacement of the block 92 in the
cylindrical recess 95. The amount of longitudinal displacement of
the block 92 within recess 95 may be governed by, among other
things, the number of threads per unit length of the shaft 91 and
of the block 92.
A pin 93 may be carried by block 92 and fixedly attached to
flow-splitting member 86 at an angle which is substantially
perpendicular to the longitudinal axis of the block. One extremity
of the pin 93 may be threaded. A threaded aperture 98 may be formed
in the flow-splitting member 86 which substantially coincides with
the transverse axis of the flow-splitting member. The threaded
extremity of the pin mates with the threaded aperture 98 of the
flow-splitting member 86. It is seen that rotational displacement
of shaft 91 causes longitudinal displacement of block 92 and
displacement of the pin 93 and hence longitudinal displacement of
the flow-splitting member 86. The pin 93 may be slidably displaced
in guide slot 79 provided by the cooperative relationship of
housing half 101 and housing half 102. One of the several functions
of the slot is to substantially prevent the pin and the block 92
from rotating with the shaft 91 as the shaft is rotatably
displaced. The flow-splitting member 86 is indirectly driven by
rotation of shaft 91 whereas in the embodiment shown in FIG. 2,
rotation of shaft 49 directly drives flow-splitting member 46.
An initial adjustment of the chamfer 90 with respect to the
flow-splitting member 86 may be desirable so that the cooperative
relationship between the flow-splitting member 86 and its
cooperatively associated chamfer provides the desired restriction
for any given position of the flow-splitting member with respect to
its cooperatively associated chamfer. To accomplish the adjustment,
plug 99 sealing one end of bore 100 may be rotated to thereby
longitudinally move plug 99 with respect to the flow-splitting
member 86 until the desired relationship between the frustoconical
member 88 and chamfer 90 is achieved. Frustoconical member 87 and
chamfer 89 would have its cooperative relationship established by
rotating shaft 91 prior to the adjustment of member 88 with respect
to its cooperatively associated chamfer 90. It is understood that
the position of member 87 with respect to chamfer 89 would remain
unaltered during the initial positioning of member 88 with respect
to chamfer 90.
The configuration of one or each of the members 87 and 88 of the
flow-splitting member 86 may be shaped different from the shape
illustrated in FIG. 3. For example, the member 86 and/or the member
87 may have a convexed side configuration, a concaved side
configuration and the like in lieu of the side configuration
illustrated. The chamfers 89 and 90 provided in the housing 81 may
be similarily altered so as to fit with the members 89 and 90 when
the members engage therewith.
Referring to FIG. 4 of the drawing, an embodiment of the present
invention is illustrated which automatically regulates the airflow
rate in a portion of the system. The embodiment is indicated by the
reference numeral 10'. The apparatus 10' includes means 34 which
automatically divides a fluid flow input from source 16 of
compressed air into a plurality of fluid flow outputs, a fluidized
bed 12 which includes a reservoir 27 retaining particulate material
13 and includes a suitable fluid-activated pump 14 which draws the
material 13 from the bed 12, and a dispensing device 15 which
dispenses the material 13 toward an article (not shown) to be
coated with the material 13.
Several of the means which are used in FIG. 1 may also be adaptable
for use with the embodiment illustrated in FIG. 4. Where the means
illustrated in FIG. 1 have been used in FIG. 4, the same reference
numerals have been used to indicate these means. For example, the
fluidized bed 12 of FIG. 1 may be used in the embodiment of FIG. 4.
The structure and function of each of the means illustrated in FIG.
4 which carries the same reference numeral as the means illustrated
in FIG. 1 is identical to the means illustrated in FIG. 1.
The automatic fluid divider 34, connected to source 16 of
compressed air by means of conduit 19, may include a means which is
capable of automatically dividing the compressed fluid supplied
thereto by the source 16 into at least two fluid outputs in
response to a control signal. The control signal is supplied to the
fluid divider by way of conduit 66. A particular pressure of the
control signal may correspond to an event such as a particular rate
of speed of a conveyor (not shown). The pressure of the control
signal may be varied so as to correspond to the varying rate of
speed of the conveyor.
In the embodiment shown in FIG. 4, the flow divider 34 includes at
least a pair of pressure regulators 31 and 32. Regulator 31
includes a control port 60, an inlet port 64 and an outlet port 61.
Regulator 32 includes a control port 62, an inlet port 65 and an
outlet port 63. The sum of the fluid flow rates at the output ports
61 and 63 of the automatic fluid divider 34 is substantially equal
to the fluid flow at the input port to the automatic fluid
divider.
The operation of pressure regulators 31 and 32 is controlled by the
magnitude of the pressure of the control signal present at control
ports 60 and 62 of the regulators. The control signal is provided
by control signal source 64 which is connected to control ports 60
and 62. Assuming that no control signal appears at control port 60
of the pressure regulator 31, regulator 31 is biased to a "closed"
position so that fluid from source 16 connected to the inlet port
64 of regulator 31 is not permitted to flow therethrough. When a
control signal is caused to appear at control port 60 by the
activation of source 64 the regulator 31 is biased to an "open"
position. The amount of compressed air from source 16 which is
permitted to flow through regulator 31 is proportional to the
degree that regulator 31 is biased "open." The fluid flow rate
through pressure regulator 31 from source 16 connected to regulator
31 is proportional to the magnitude of pressure of the control
signal present at control port 60 of the regulator. Assuming that
no control signal from source 64 appears at control port 62 of
pressure regulator 32, the pressure regulator is biased to the
"full open" position causing a fluid flow at output port 63 from
the source 16 through inlet port 65 of the regulator. The
appearance of a control signal at control port 62 causes the fluid
flow at outlet port 63 to decrease in proportion to the magnitude
of the pressure of the control signal provided by source 64.
As illustrated in FIG. 4 of the drawing, a suitable conduit 2
connects the output port 63 of the pressure regulator 32 to the
conduit 22 at a junction just downstream from the fluid activated
pump 14. It is seen that regulator 32 and conduit 20 cooperate to
shunt the air flowing therethrough from the source 16 around the
fluidized bed to hose 22. A suitable conduit 21 connects the output
of pressure regulator 31 to the inlet of the fluid-activated pump
14. The regulator 31 is used to regulate the airflow rate through
the fluid-activated pump 14 and thereby regulate the rate at which
the particulate material 13 is drawn from the reservoir 27 of the
fluidized bed 12.
Hose 22 is used to carry the particulate material 13 from the
open-throated venturi tube of the fluid pump 14 to dispensing
device 15.
The control signal at control ports 60 and 62 of pressure regulator
31 and of pressure regulator 32 respectively are derived from any
suitable source 64 capable of generating a control signal in
response to the occurrence of an event. The source 64 may provide a
control signal having a pressure magnitude which relates to an
event such as a process function. For example, the control signal
may be initiated by a suitable sensor (not shown) which is capable
of acting on the source 64 so as to cause the source 64 to provide
a control signal having a pressure proportional to the event such
as the speed of a conveyor (not shown) carrying articles (not
shown) to be coated past the dispensing device 15. The parameters
of the system may be established so that a stationary conveyor does
not activate the source 64. A deactivated source 64 may be
programmed so as not to provide a control signal thereby causing
pressure regulator 31 to be biased to the "closed" position, that
is preventing fluid flow therethrough from source 16 and causing
pressure regulator 32 biased to an "open" position, that is
permitting substantially all of the compressed air of the source 16
to flow therethrough thereby shunting the compressed air of source
16 around the pump 14 in fluidized bed 12. Since the compressed air
of source 16 is shunted around the fluid-activated pump 14, no
particulate material is caused to be delivered to spray gun 16.
Causing an event to occur which activates the sensor (not shown)
connected to source 64, such as activating the conveyor, source 64
is caused to generate a control signal which is proportional to the
rate of displacement of the conveyor.
The control signal activates the pressure regulator 31 thereby
causing compressed air from source 16 to flow therethrough. The
control signal also causes the regulator to reduce the amount of
compressed air which flows therethrough from source 16. The
increase in airflow rate flows therethrough from source 16 through
regulator 31 is proportioned to the airflow rate through regulator
32 thereby dividing the flow from compressed air source 16 between
conduits 21 and 22. It is seen that as the airflow rate through the
fluid-activated pump 14 is increased, a greater amount of
particulate material will be drawn from the fluidized bed 12, and
delivered to the spray gun 15. Thus, the output of the gun may be
varied according to the speed of the conveyor to maintain a
constant coating thickness on the parts to be coated.
A suitable detachable hose union means (not shown) may be used to
connect the hose 20 from the fluid divider and the hose of the
fluidized bed to the hose 22 connected to the dispensing
device.
The present invention is not intended to be limited by the
disclosure therein, changes and modifications may be made by those
skilled in the art without departing from the spirit and scope of
the present invention. Such modifications are considered to be
within the purview and scope of the invention.
* * * * *