Note: Descriptions are shown in the official language in which they were submitted.
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BACKGROUND OF
THE INVENTION
The present invention relates to an apparatus and
method for making a post-foaming gel.
Before the present invention, attempts have been
made to add foaming agents, such as pentane/butane mixtures
to gel bases in conventional partly filled pressure vesseli
to make a post-foaming gel. However, any post foaming gel
of cosmetically acceptable stiffness will tend to foam
spontaneously when exposed to atmospheric pressure if it
contains bubbles of air or hydrocarbon. These act as nuclei
for foaming, by expanding and shearing the gel in their
immediate vicinity. This means that pentane/butane mixtures
cannot be incorporated into gel base in a conventional,
partly-filled pressure vessel, even when the headspace is
pressurized with air or nitrogen. Inevitably some of the
water-soluble gas will be entrained in the gel. The
resulting spontaneous foaming makes filling into cans very
difficult and messy. Even then the product will not settle
down on storage to give a satisfactory result.
Taking a potentially 'easy' situation, such as
adding only isopentane(B.Pt. 29C) or n-pentane (B.Pt.
37C), there are still problems. Assuming a good gel is
produced by cold mixing, you will find that at temperatures
around 20C the mixing does vaporise significant amounts
of foaming agent and the resulting gel is foamy.
~ hese bubbly gels are not suitable for packing into
cans because the external propellant used with the cans
gives insufficient pressure to collapse the bubbles on
storage. This is largely due to the fact that these gels
have a yield value such that they resist ~he applied
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pressure (or fail to transmit the full effect to the bubbles).
A post-foaming gel is disclosed in U.S. Patent
3r541r581- A continuous method and apparatus to make a post-
foaming gel is disclosed in U.S. 4~405~489. The filling of an
aerosol can containing an interior plastic bag which holds the
product to be dispensed is disclosed in U.S. 4r589rg52.
The U.S. Patent 4r405r489 discloses metering pumps 24
and 25 having a single device mechaniæm 26 on their own drive
mechanism.
SUMMARY OF THE INVENTION
The present invention provides an apparatus for
making a post-foaming gelr comprising:
means for pumping a gel base;
means for measuring the flow rate of the pumped gel
base;
means responsive to the measuring means for pumping a
foaming agent at a flow rate in a predetermined ratio to the
flow rate of the gel base;
means for introducing the foaming agent to the gel
base; and
means for forming the post-foaming gel or emulsion
from the introducing means.
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The desired ratio of the base and foaming agent is
automatically determined and varied as required.
Preferably the apparatus is flame proof, and is of
significant construction at reduced cost.
The rate of the base pumping means may be controlled,
and preferably means is provided for smoothing out the flow
pulsation from the base pumping means.
Preferably the foaming ayent pumping means is
variable, and there 1~ means for measuring the flow rate of the
foaming agent passing through the foaming agent pumping means.
Preferably the flow rates of the base and foaming
agent can be compared.
Another feature of the invention is the provision o~
means for bleeding air and vapor from the foaming agent.
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The apparatus may include means for storing the foamed
gel or emulsion under pressure, and the gel or emulsion may be
selectively passed to a plurality of storage cylinders.
Maximum and minimum filled conditions of the container may be
determined.
Preferably the apparatus provides a continuous gel manu-
facture with simultaneous can filling capacity.
The pumping means may be interrupted in the event of the
maximum and minimum filled conditions of the container.
Further features will become more fully apparent in the
following description of the embodiments of this invention and
from the appended claims.
In the drawings:
Figure 1 is a diagrammatic view of an apparatus for making
a post-foaming gel of the present invention;
Figure 2 is a diagrammatic view of a pair of storage
cylinders for the apparatus of Figure l;
Figure 3 is a sectional view of a metering pump for the
apparatus of Figure l;
Figure 4 is a sectional view of a storage cylinder for the
apparatus of Figure l; and
Figure 5 is a diagrammatic view of a pneumatic stroke
positioner.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to Figure 1, there is shown an apparatus
generally designated 10 for making a post-foaming gel from a
gel base and foaming agent. The apparatus 10 has a storage
container 12 for retaining the gel base, with the container 12
being connected to a pump 14 by a conduit 16. Typically, the
pump 14 is capabl~ o.f pumping 1,000 liters/hour, and the
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rate of the pump 14 may be manually varied by a control device
18 on the pump 14.
The pump 14 is connected by a conduit 20 to a non-return
valve 22 to prevent passage of the foaming agent to the pump
14 and render the apparatus flame-proof. The valve 22 is
connected by a conduit 24 to a pressure relief
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valve 26 to prevent excessive pressure in the apparatus 10.
~ The gel base is passed through a conduit 28 to a pulsation
dampener 30 to smooth out flow pulsation of the pumped gel
base. The gel base passes from the dampener 30 through a
conduit 32 to a flow meter 34 which determines the flow rate
of the gel base between minimum and maximum limits, such as
a range of 0-1000 liters per hour. The flow meter 34
generates an electrical signal indicative of the base flow
rate. ~he signal is fed to a current-to-pressure convertor
which transforms the electrical Rignal into a pneumatic
signal for a purpose which will be described below. The gel
base then passes through a conduit 36 to a location 38 in
the apparatus 10.
A source of the foaming agent ;s retained in a
container 40, and the foaming agent passes from the
~-container 40 through a conduit 42 to a pump 44 which
maintains the foaming agent in liquid form. The foaming
agent passes from pump 44 through a conduit 46 to a valve
48.
The apparatus 10 has a pneumatic stroke positioner
51 based on a highly responsive, fast acting wedge/cylinder
mechanism which adjusts the setting in proportion to 0.2 to
1 bar (3 to 15 lb/in.2) air signal 49. Failure of the air
signal or absence of air pressure, returns the stroke
setting to zero.
With reference to Figs. 1, 3, and 5, the foaming
agent then passes through a conduit 50 to the pump-head 5i
of a metering pump 52. The pump 52 has a first one-way ball
valve 54 which moves between a first position away from a
seat 56 to permit passage of the foaming agent through the
valve 54 into a chamber 58, and a second position against
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the seat 56 to prevent passage of the foaming agent from the
chamber 58 to the conduit 50. The pump 52 has a second
one-way ball valve 60 which moves from a first position away
from a seat 62 to permit passage of the foaming agent from
the chamber 58 to a conduit 64, and a second position
against the seat 62 to prevent passage of the foaming agent
or gel base from the conduit 64 to the chamber 58. The pump
52 has an elongated cylinder 66 which slidibly receives a
piston 68 connected to a shaft 70, and the piston 68 is
reciprocated in the cylinder 66 while cooperating with the
first and second valves 54 and 60 in order to pump the
foaming agent into and out of the chamber 58. The rate of
reciprocation of the piston 68 is controlled by the
pneumatic signal from the flow meter 3~ in order to control
the pumping rate of the foaming agent at a predetermined
ratio relative to the flow rate of the gel base. The pump
52 i9 callbrated to obtain the desired ratio of gel base and
foaming agent, and the ratio may be changed by suitable
calibrations if desired.
The pumped foaming agent passes through the conduit
64 to a pressure relief valve 72 to prevent excessive
pressure of the foaming agent in the apparatus 10, and the
foaming agent then passes through a non return valve 74
which prevents backward movement of the foaming agent in the ~;
apparatus 10. The foaming agent passes through a flow meter
75 which determines the flow rate of the foaming agent such ;~
that the flow ratio of the gel base and foaming agent can be
compared. The foaming agent then passes through a conduit
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76 to a bleed off valve 78 to bleed off air or vapor while a
manual valve 80 is clo~ed to verify that the foaming agent
is in liquid form. Once air or vapor is bled from the -~
foaming agent, the valve 80 is opened to permit passage of
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the pumped foaming agent to the location 38 to permit
contact with the pumped gel base.
Both the gel base and foaming agent are pumped frcm
location 38 through a conduit 82 to a mixer 84 which may be
a static or dynamic mixer or both. The mixer 84 forms the
post-foaming gel or an emulsion from the gel base and
foaming agent depending upon the conditions of the apparatus
10, such as temperature, The gel or emulsion then passeY
through a conduit ~6 to a valve 8~ for a purpose which will
be described below,
The apparatus 10 has a storage cylinder 90 having a
chamber 92 and a piston 94 slidibly received in the chamber
92, with the piston 94 having a shaft 9~ which extends out
of the cylinder 90. The piston 94 separates the chamber 94
into a first compartment 98 to receive the gel or emulsion
and a second compartment 100 to receive a compressed gas
through a conduit 102 from a source of pressurized gas, such
as 50-100 pounds/~quare inch, which may be varied to control
pressure on the piston 94. The gel or emulsion is pumped
into the first compartment 98 against the pressure on the
piston 94 which is controlled to obtain a pressure in the
preferred range of 60-100 pounds/square inch in order to
maintain the foaming agent in a liquid condition without
vaporizing.
Once the cylinder 90 is full, the valve 88 may be
closed and the gel or emulsion is passed through a valve 104
to suitable containers. In the event o~ the gel, it is
passed into container 106 with an open top after which a
valve is attached to the container 106 for dispensing the
gel once the container 106 is prepared with a suitable
propellant known to the art. In the event of the emulsion,
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it is passed through the activated valves 108 of suitable
containers 110 know to the art in order to obtain a
secondary mixing by the valves 108 and form the emulslon
into the post-foaming gel in the containers 110, The
G contalners are prepared with a suitablo propellant as known
to the art in order to dispense the gel from the containers
110 when the valves 108 are activated.
In a preferred form, with reference to Fig. 2, the
apparatus has a pair of cylinders 90 and 112 of the type
previously described. The gel or emulsion is passed from
the mixer 84 through a conduit 114. The gel or emulsion
passes from conduit 114 through a conduit 116 with a manual
valve 118 associated with the conduit 116 connected to the
container 90. The gel or emulsion also passes from conduit
114 through a conduit 120 with a manual valve 122 associated
with the conduit 120 to the cylinder 112. The valves 118
and 122 may be controlled as desired to sequentially fill
the cylinders 90 and 112, after which the gel or emulsion is
emptied from the cylinders 90 and 112 in a manner as
previously dQscribed. As shown, the conduit 120 may have a
temperature probe 124 in order to measure the temperature of -~
the gel or emulsion.
A preferred form of the cylinder 90 is shown in -~
Fig. 4, in which like reference numerals designate like
parts. In this embodiment, the gel or emulsion G passes
through a conduit 126 into the first compartment ga of the
cylinder 90, in a manner as previously described, and the ;;
gel or emulsion passes from the cylinder 90 out of a conduit
12~ to fill the containers eor dispensing of the product.
As shown, the apparatus 10 has a high level lower switch 130
and a low level upper switch~ 132 which may be activated by
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the position of a pin 134 on the piston shaft 96. When the
cylinder 90 is sufficiently full of the gel or emulsion G,
the switch 130 is activated, and the apparatus, including
the pumps, is turned off to prevent the build up of pressure
in the apparatus when a maximum quantity of the product ls
in the cylinder 90. Normally, the piston 94 of cylinder 90
may be used as a buffer to pass the product from the conduit
126 through the cylinder 90 into the conduit 128 until
activation of the switch 132 is discontinued, and passage of
the product through the cylinder is thereaEter maintained
unle~s the switch 132 is contacted again in which event the
filling apparatus downstream from conduit 128 is switched
off to prevent 'starvation' of gel or e,ilulsion to the
filling apparatus.
The gel base is made in the following manner according
to the formulation set forth below:
(1) Add approximately 20~ of the water to a closed
mixing ves~el.
(2) Add fatty acid Oo the mixing vessel and then the
GMS/color then heat to 80-85 C until all powders are molten.
(3) Add the triethanolamine to the vessel with
agitation to form a soap. Cool to 60C. Add the Hydroxyethyl
cellulose.
-_ (4) Cool to 40C and add the Hydroxypropyl cellulose.
(5) Add the sorbitol solution, with agitation, to the
aqueous soap.
(6) Cool the mixture to 30C, add the perfume with
agitation.
The gel base has the following formulation:
BASE %
Palmitic Acid 8.0 - 10.0
Stearic Acid 1.0 - 3.0
Triethanolamine 5.5 - 7.5
Sorbitol - 70~ solution up to 3.0
Hydroxyethyl cellulose 0.1 - 0.4
Hydroxypropyl cellulose0.05 - 0.15
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- Glyceryl Monostearate 0.4 - 0.6
Perfume q.s.
Coloring Material q.s.
Water to 100~
The ~inished product has the following formulation:
-~ FINISHED PRODUCT
~ase as above 97.0 - 9~.0
Iso-Pentane 1.5 - 1.8
Iso-Butane 0.5 - 1.2
In accordance with the present invention, the
apparatus 10 provides continuous gel manufacture with
simultaneous can filling capacity. The pre~ent invention is
thus an improvement over batch process ~el manufacture due
to reduced production time, and the product can be filled
immediately ~within 1-2 minutes) of being formed.
~; The foregoing detailed description is given for
clearness of understanding only, and no unnecessary
limitations should be understood therefrom, as modifications
will be obvious to those skilled in the art.
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