U.S. patent number 3,876,145 [Application Number 05/435,685] was granted by the patent office on 1975-04-08 for apparatus for ejecting a mixture of a plurality of liquids.
This patent grant is currently assigned to Gusmer Corporation. Invention is credited to Frederick E. Gusmer, Joseph E. Hayes, Jr., Carl W. Sundberg, Jr..
United States Patent |
3,876,145 |
Gusmer , et al. |
April 8, 1975 |
Apparatus for ejecting a mixture of a plurality of liquids
Abstract
Apparatus for ejecting a mixture of liquids, e.g. urethane foam,
comprises a cylindrical chamber into which the liquids are
separately introduced under pressure and mixed and ejected from the
open end of the chamber. A reciprocable plunger alternately exposes
the inlets in its rear position and seals the inlets from each
other and purges the chamber in its forward position. The inlets
are axially spaced apart and separated from each other by a throat
that has interference fit with the plunger in the forward position
of the plunger, the plunger having for this purpose an elastic
deformable surface.
Inventors: |
Gusmer; Frederick E.
(Mantoloking, NJ), Sundberg, Jr.; Carl W. (Chatham, NJ),
Hayes, Jr.; Joseph E. (Manasquan, NJ) |
Assignee: |
Gusmer Corporation (Middlesex,
NJ)
|
Family
ID: |
23729380 |
Appl.
No.: |
05/435,685 |
Filed: |
January 23, 1974 |
Current U.S.
Class: |
239/112; 239/569;
239/414 |
Current CPC
Class: |
B05B
15/55 (20180201); B29B 7/7678 (20130101); B29B
7/7438 (20130101) |
Current International
Class: |
B29B
7/76 (20060101); B05B 15/02 (20060101); B29B
7/00 (20060101); B29B 7/74 (20060101); B05b
015/02 () |
Field of
Search: |
;239/112,115-118,113,379,414,415,527,528,569 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Wood, Jr.; M. Henson
Assistant Examiner: Church; Gene A.
Attorney, Agent or Firm: Young & Thompson
Claims
Having described our invention, we claim:
1. Apparatus for ejecting a mixture of a plurality of liquids,
comprising a mixing chamber having an outlet opening and a
plurality of spaced inlets which are spaced different distances
from said outlet opening, means for separately introducing
different liquids into the chamber through said inlets, a plunger
reciprocable in the chamber between forward and rear positions, the
differently spaced inlets communicating with the chamber and with
each other in said rear position of the plunger, and means sealing
against the plunger in the forward position of the plunger to seal
said inlets from each other, the forward end of the plunger being
forward of all said inlets in said forward position of the plunger
and being rearward of all said inlets in said rear position of the
plunger.
2. Apparatus as claimed in claim 1, in which the surface of one of
said plunger and sealing means is an elastic deformable
material.
3. Apparatus as claimed in claim 2, in which the surface of said
plunger is an elastic deformable material.
4. Apparatus as claimed in claim 1, said sealing means comprising
an annular throat in which said plunger reciprocates with an
interference, said plunger being in sealing contact with said
throat in said forward position and exposing all said inlets to
each other in said rear position, said forward end of said plunger
being disposed on opposite sides of said throat in said forward and
rear positions, said inlets being disposed on opposite sides of
said throat.
5. Apparatus as claimed in claim 4, said inlets extending through
slots formed in the ends of separable members that abut said throat
on opposite sides of said throat, said throat closing one side of
each of said slots.
6. Apparatus as claimed in claim 5, said opposite sides of said
throat converging radially inwardly.
7. Apparatus as claimed in claim 6, said slots on opposite sides of
said throat converging radially inwardly.
8. Apparatus for ejecting a mixture of a plurality of liquids,
comprising a mixing chamber having an outlet opening and a
plurality of spaced inlets which are spaced different distances
from said outlet opening, means for separately introducing
different liquids into the chamber through said inlets, a plunger
reciprocable in the chamber between forward and rear positions, the
differently spaced inlets communicating with the chamber and with
each other in said rear position of the plunger, and means sealing
against the plunger in the forward position of the plunger to seal
said inlets from each other, said plunger adjacent said sealing
means comprising a sleeve of elastic deformable material on a metal
rod.
9. Apparatus as claimed in claim 8, said rod having grooves on its
outer surface which are only partially filled by the material of
said sleeve.
10. Apparatus for ejecting a mixture of a plurality of liquids,
comprising a mixing chamber having an outlet opening and a
plurality of spaced inlets which are spaced different distances
from said outlet opening, means for separately introducing
different liquids into the chamber through said inlets, a plunger
reciprocable in the chamber between forward and rear positions, the
differently spaced inlets communicating with the chamber and with
each other in said rear position of the plunger, and means sealing
against the plunger in the forward position of the plunger to seal
said inlets from each other, said sealing means comprising an
annular throat in which said plunger reciprocates with an
interference fit, said plunger being in sealing contact with said
throat in said forward position and exposing all said inlets to
each other in said rear position, said forward end of said plunger
being disposed on opposite sides of said throat in said forward and
rear positions, said inlets being disposed on opposite sides of
said throat, said inlets extending through slots formed in the ends
of separable members that abut said throat on opposite sides of
said throat, said throat closing one side of each of said slots,
said separable member on the same side of said throat as said
outlet opening being carried by a floating packing sleeve through
which said plunger extends in said forward position.
11. Apparatus for ejecting a mixture of a plurality of liquids,
comprising a mixing chamber having an outlet opening and a
plurality of spaced inlets which are spaced different distances
from said outlet opening, means for separately introducing
different liquids into the chamber through said inlets, a plunger
reciprocable in the chamber between forward and rear positions, the
differently spaced inlets communicating with the chamber and with
each other in said rear position of the plunger, and means sealing
against the plunger in the forward position of the plunger to seal
said inlets from each other, there being a plurality of said inlets
for each said liquid, all the inlets for one said liquid being
equally peripherally spaced about said chamber and being the same
distance from said outlet opening.
12. Apparatus as claimed in claim 11, all said inlets for each said
liquid being offset the same distance and in the same direction
from the axis of the chamber.
13. Apparatus for ejecting a mixture of a plurality of liquids,
comprising a mixing chamber having an outlet opening and a
plurality of spaced inlets which are spaced different distances
from said outlet opening, means for separately introducing
different liquids into the chamber through said inlets, a plunger
reciprocable in the chamber between forward and rear positions, the
differently spaced inlets communicating with the chamber and with
each other in said rear position of the plunger, and means sealing
against the plunger in the forward position of the plunger to seal
said inlets from each other, said inlets farthest from said outlet
opening being inclined forwardly and said inlets nearest said
outlet opening being inclined rearwardly.
Description
The present invention relates to apparatus for ejecting a mixture
of liquids, and more particularly to ejecting a homogeneous mixture
of liquids which must be mixed as nearly concurrently with ejection
as possible. The invention has utility in a number of fields, such
as the ejection of foam, of highly exothermic mixtures, and of
thermosetting resin formulations. It will be disclosed, by way of
example, in connection with the ejection of foam, particularly foam
of the urethane type.
For some applications, the present invention will be used to eject
mixtures in a divided form such as spray or droplets or larger
cohesive units. However, it is to be understood that the present
invention is also useful for the ejection of mixed liquids in a
continuous stream.
It is also to be understood that although some of the ejection of
mixed liquids according to the present invention will be against a
solid substrate, it is also within the purview of the present
invention to eject mixed liquids into a partially or completely
enclosed region such as a chamber. Thus, the present invention is
amenable to such applications as spray coating on a solid
substrate, caulking by injection of a continuous stream into a
joint or seam or the like, the insertion of insulation by the
ejection of a continuous or particulate stream into a space to be
insulated, the formation of shaped bodies of foamed or unfoamed
plastics by ejection of a mixture of liquids into a mold cavity,
the formation of unshaped bodies of foamed plastics by ejection of
the mixture onto a moving conveyor, packaging such as polyurethane
packaging, or other processes which will be obvious to persons
having ordinary skill in this art.
The present invention is an improvement on U.S. Pat. No. 3,263,928,
Aug. 2, 1966. In the device of that patent, as in other devices in
this field, liquids have been mixed and ejected by separately
introducing them into a mixing chamber having an open outlet end,
from spaced inlets that open into the chamber at about the same
distance from the outlet along the axis of the chamber, in a region
of the chamber that is swept by a plunger that in its rearward
position exposes the inlets and permits the liquids to flow into
the chamber and mix in the chamber and be ejected from the open end
of the chamber, and upon movement toward its forward position
simultaneously closes all the inlets and then sweeps the remaining
mixed liquids forwardly out of the chamber.
The aim of such devices is to prevent the retention or accumulation
in the chamber of any substantial quantity of the mixture of
liquids. These liquids are ordinarily mutually reactive to set up
to a solid which would impede operation of the device if not
completely purged by the plunger.
It has been found, however, that in practice, the plunger still has
a tendency to stick both in the closed and in the open position. It
has also been found to be difficult, with the known devices, to
maintain good distribution of material across the spray pattern.
Finally, there is a tendency in such known devices, for the
reactive liquids to seep past the parts of the apparatus in the off
position, and to mix and react and impede operation of the
device.
Accordingly, it is an object of the present invention to provide
apparatus for ejecting a mixture of a plurality of liquids, in
which the tendency toward sticking of the plunger in the open
and/or closed position is reduced.
Another object of the present invention is the provision of such
apparatus, which has good distribution of material across the spray
pattern.
Still another object of the present invention is the provision of
such apparatus, in which seepage of the liquids in the closed
position is eliminated.
Still another object of the present invention is the provision of
such apparatus, having improved plunger construction.
Finally, it is an object of the present invention to provide such
apparatus, which will be relatively simple and inexpensive to
manufacture, easy to operate, maintain and repair, and rugged and
durable in use.
Other objects, features and advantages of the present invention
will become apparent from a consideration of the following
description, taken in connection with the accompanying drawing, in
which:
FIG. 1 is a side elevational view of apparatus according to the
present invention;
FIG. 2 is an enlarged cross-sectional view of the valve and ejector
outlet assembly of the present invention;
FIG. 3 is an end view of the rear impinger viewed from the right in
FIG. 2;
FIG. 4 is an end view of the front impinger viewed from the left in
FIG. 2; and
FIG. 5 is an enlarged fragmentary cross-sectional view of the
plunger.
Referring now to the drawing in greater detail, there is shown a
gun according to the invention, indicated generally at 1, and
including a head 3. Conduits 7 and 9 each supplies a different
liquid to head 3. Sources of supply for these different liquids
under pressure to conduits 7 and 9 are not shown but may take any
usual form. An air hose 11 supplies compressed air to an air cap
13. Air cap 13 directs air against and along the exterior of valve
nozzle 67 for the purpose of cleaning the front end of the
apparatus. For this purpose, compressed air can be used at a
relatively low gauge pressure, for example, about 1 to 10 p.s.i.g.
In this way, the accumulation of deposits of reactive material
about the outlet of the spray equipment is avoided. This compressed
air is not intended to assist in atomizing when spraying.
A plunger 15 is reciprocable in head 3. The plunger 15 adjacent its
forward or free end is of cylindrical contour and of uniform
external diameter. Adjacent its rear end, plunger 15 carries an
adjustment nut 17 screw-threadedly thereon. A coil compression
spring 19 bears between adjustment nut 17 and the rear end of a
housing 21 carried by the gun and continuously urges plunger 15
forwardly. A piston 23 is slidable in a cylinder formed in the rear
of the gun. A hollow tubular sleeve 25 extends forwardly from
piston 23 and encompasses plunger 15 to guide and support plunger
15 and also to guide piston 23.
An air hose 27 under the control of valve 29 brings compressed air
to the forward side of piston 23 to force piston 23 rearwardly
against adjustment nut 17 and to force adjustment nut 17 and with
it plunger 15 rearwardly against the action of spring 19. Valve 29
is selectively opened and closed by actuation of an actuating
button 31 carried by the handle 33 of the gun. Depressing button 31
opens valve 29 to admit compressed air 27 to the chamber forwardly
of piston 23, to drive the piston rearwardly until the rear end of
plunger 15 contacts an adjustable plunger stop 35 screw-threadedly
received in the rear of housing 21 and rotatably adjustable to
advance or retract its forward end thereby to fix the rearmost
position of plunger 15. The forwardmost position of plunger 15 is
set by manipulation of adjustment nut 17.
The forward end of plunger 15 is disposed in a mixing chamber 37
within head 3. Mixing chamber 37 has an outlet end 39 and is of
substantially uniform cross-sectional configuration from end to end
thereof, including outlet end 39. In general, it is preferred that
mixing chamber 37 and outlet end 39 thereof have a substantially
uniformly cylindrical shape.
Thus far, the arrangement of the present invention can be generally
as in the above-identified patent. The particular novelty of the
present invention is as follows:
Remembering that in the prior art, the inlets for the different
liquids are generally opposed to each other, in the present
invention, the inlets of the different liquids, shown at 41 and 43
in FIG. 2, are axially spaced apart lengthwise of the chamber 37,
and are separated from each other by the plunger 15 in the closed
position. In the open position, however, when the plunger is
withdrawn to the position indicated for example at x in FIG. 2,
then the inlets 41 and 43 both communicate with the mixing chamber
and the different liquids can enter and mix therein and exit
through the outlet end 39.
An annular throat 45 is externally screw threadedly secured in head
3 and can be rotated into sealingly seated engagement against a
conical shoulder 46 in head 3 and has a radially inwardly extending
annular projection 47 thereon of generally truncated conical
cross-sectional configuration that terminates inwardly in a
radially innermost surface of throat 45 which has an interference
fit with plunger 15. That is, the inner diameter of throat 45 is
less than the normal outer diameter of plunger 15. To accommodate
this interference fit, the forward end of plunger 15 is comprised
by an externally screw threaded metal rod 49 that is surrounded by
a sleeve 51 of elastic deformable material having a low coefficient
of sliding friction, preferably an elastomer and more preferably an
organic elastomer, for example solid polyamide, e.g. nylon. The
outer diameter of the screw threads on rod 49 is greater than the
inner diameter of sleeve 51, so that sleeve 51 in turn has an
interference fit with rod 49. For example, if sleeve 51 were
one-eighth-inch outside diameter nylon tubing with a wall 0.020
inch thick, then the threads of rod 49 could have an outside
diameter of 0.090 inch, so that they are greater in diameter than
the inside diameter of sleeve 51 by 0.005 inch. Similarly, the
inside diameter of throat 45 may for example be 0.0025 inch, .+-.
0.0005 inch, smaller than the outside diameter of sleeve 51.
The interference fit between throat 45 and sleeve 51 prevents
seepage of liquid past throat 45 in the closed position shown in
full line in FIG. 2, and also provides a sweeping or cleaning
action of the throat relative to the plunger in both directions of
movement of the plunger. The interference fit between sleeve 51 and
threaded rod 49, on the other hand, assures retention of sleeve 51
on rod 49; and as the material of sleeve 51 does not entirely fill
up the grooves between the threads on rod 49, as seen in FIG. 5,
these unfilled spaces permit displacement of the material of sleeve
51 radially inwardly as the sleeve passes through throat 45. Thus
the interference fit between throat 45 and sleeve 51 does not cause
a wave or lump of material of sleeve 51 to move axially along
plunger 15. In this way, the arrangement shown in FIG. 5 performs
the unique dual function of properly retaining sleeve 51 on the
plunger, and also of permitting radially inward deformation of
sleeve 51 while passing through throat 45.
Throat 45 is internally screw threaded to receive and retain the
radially outwardly extending flange 53 of a rear impinger 55
through which plunger 15 passes. Flange 53 is slotted at 57 to
permit liquid from inlet 41 to pass through slots 57, and then
through smaller slots 59 to mixing chamber 37. The forward end of
impinger 55 is conical and of the same shape as the adjacent face
of throat 45, so that the adjacent conical face of throat 45 closes
the forward sides of slots 59. Slots 59 are forwardly inclined at
an angle of about 20.degree. and are axially offset as seen in FIG.
3 to produce a desirable vortical movement in chamber 37 to promote
mixing.
On the other side of throat 45, a front impinger 61 is provided,
with a conical rear end traversed by slots 63 to provide
communication for the other liquid from inlet 43 through slots 63
to mixing chamber 37. The rear end of front impinger 61, which is
the left end as seen in FIG. 2, is conical and of the same shape as
the adjacent face of throat 45 and so that face of throat 45 closes
the rear side of slots 63. Slots 63 are rearwardly inclined at an
angle of about 20.degree. and are axially offset as seen in FIG. 4,
to promote a desirable vortical motion for mixing purposes.
The provision of impingers 55 and 61 that bear against opposite
sides of throat 45 and that have slots cut in their ends adjacent
throat 45 with throat 45 closing the slots, greatly facilitates the
provision of openings for the passage of the liquids into the
reaction chamber, because it is much easier to machine slots in the
ends of the impingers, than it would be to provide accurate holes
through a cylindrical sleeve.
The axial spacing of slots 59 and 63 makes it possible to increase
the total number of the slots, and this has several beneficial
results. In the first place, increasing the number of slots and
spacing them apart axially improves the dispersion of the liquid as
it leaves the gun and thus helps to distribute the liquid better
within the spray pattern. In the second place, increasing the
number of slots decreases the cross section of each slot and hence
the cross section of the streams prior to mixing and so facilitates
the fine division and mixing of the streams.
Front impinger 61 is secured to a packing sleeve of elastic
deformable material having a low coefficient of sliding friction,
preferably an elastomer and more preferably an organic elastomer,
such as polytetrafluoroethylene. The rear end of sleeve 65, in
turn, is loosely disposed in nozzle 67 that is screw threadedly
secured in head 3, so that front impinger 61 and the rear end of
packing sleeve 65 float together as a unit relative to nozzle 67,
with the result that the front end assembly is self-aligning and
the problem of maintaining extremely small manufacturing tolerances
is thereby avoided. The front end of packing sleeve 65 seals in
nozzle 67.
To the rear of the mixing chamber, the assembly is completed by a
packing sleeve 69 of a material such as that of sleeve 65, which
may be tightened with a packing adjustment screw 71 screw
threadedly received in a sleeve 73 which in turn is screw
threadedly received in head 3.
In operation, the user of the gun can actuate the device by
depressing button 31, thereby opening valve 29 and causing piston
23 to move to the rear until the rear end of plunger 15 contacts
plunger stop 35. In this position, the forward or free end of
plunger 15 moves to the rear of slots 59 and 63, to the position x
in FIG. 2, and the different liquids that are supplied under
pressure to conduits 7 and 9 rush into mixing chamber 37, where
they are given a rotary or swirling movement with resultant
shearing and mixing of the streams, by virtue of the offset of
slots 59 from each other, and the offset of slots 63 from each
other. The mixing liquids thus move toward and out of outlet end 39
with a largely helical movement. The high kinetic energy of the
stream may cause the stream to subdivide into discrete particles or
drops, or not, depending on process variables well known to persons
in this field. Among these variables is the degree of offset of the
slots from the axis of chamber 37.
When the operator releases button 31, compressed air to the forward
side of piston 23 is cut off and spring 19 forces piston 23
forwardly until the piston contacts the front of its piston
chamber. In this position, which is the position of the parts shown
in FIG. 2, the forward or free end of piston 15 occupies
substantially all of outlet end 39 and preferably protrudes
somewhat out of outlet end 39. By this forward movement of plunger
15, substantially all of the mixed liquid within chamber 37 is
mechanically expelled. If the liquid is of the type that sets up
into a relatively hard substance a short time after mixing, then
the advantages of the present invention will be obvious in that
substantially no mixed liquid will be left in chamber 37 to harden.
On the other hand, the gun will be ready for use again and can
begin to function immediately upon a further retraction of plunger
15. It is thus unnecessary to clean the gun after every actuation,
as substantially no mixed liquids remain in the gun.
The advantage of the operation of the present invention, with its
axially spaced inlets, as compared to the known arrangements with
axially opposed inlets for the different liquids, is as
follows:
In the closed position, the interference fit of throat 45 prevents
any movement of any liquid past the throat along plunger 15, and so
effectively isolates the reactive liquids from each other.
Moreover, in the closed position, it is impossible for any mixed
liquids to move toward the rear packing, because this space is
already occupied by the liquid from inlet 41. Thus the rear packing
is bathed in liquid from inlet 41, which serves as an additional
seal against liquid from inlet 43.
Even in the open position of the parts, the rear packing is
protected from contact by any mixed liquid. This is because the
slots 59 and 63 serve as restrictive orifices, which let down the
pressure of the liquids from inlets 41 and 43, respectively. For
example, if the pressure in both inlets 41 and 43 were, say, 800
psi, and the reduced pressure in chamber 37, by virtue of the
pressure loss due to passage through the slots, were, say, 300 psi,
then it is obvious that the mixed liquid at 300 psi could not
migrate rearward into and contaminate the unmixed liquid from inlet
41 at 800 psi.
Moreover, even plunger 15 cannot carry backward or forward any
liquid on its surface, and thus promote even a small degree of
undesired mixture of liquids, because the interference fit between
plunger 15 and throat 45 wipes plunger 15 clean in both directions
of movement.
It is also to be noted that the forward liquid, that is, the liquid
that enters through inlet 43, is the first to enter the chamber 37
upon rearward movement of plunger 15 and the last to leave the
chamber upon forward movement of plunger 15, that is, the slots 63
are exposed before slots 59 and are closed after slots 59. As a
result, there may be a slight excess of this forward liquid at the
beginning and end of ejection. However, this is not necessarily
undesirable and can in fact even be highly desirable. It is not
necessarily undesirable, because if for example the mixture of
liquids forms a polyurethane and the rear liquid through inlet 41
is the resinous component and the forward liquid through inlet 43
is its activator containing isocyanate, then this slight excess of
isocyanate may itself react with ambient moisture even in the
absence of resin admixed therewith. On the other hand, the fact
that slots 63 are closed later than slots 59 may be highly
desirable, as it ensures that plunger 15 in its closed position, to
the extent that it is wetted at all, will be wetted with the single
liquid from inlet 43, rather than with the reactive mixture that
previously filled chamber 37.
From a consideration of the foregoing disclosure, therefore, it
will be evident that all of the initially recited objects of the
present invention have been achieved.
Although the present invention has been described and illustrated
in connection with a preferred embodiment, it is to be understood
that modifications and variations may be resorted to without
departing from the spirit of the invention as those skilled in this
art will readily understand. Such modifications and variations are
considered to be within the purview and scope of the present
invention as defined by the appended claims.
* * * * *