Note: Descriptions are shown in the official language in which they were submitted.
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A POR~LE ~ DISPENSER
THIS INVEN~ION relates to a portable foam
dispenser. More particularly, it relates to an
apparatus ~or mixing liquid catalyst and resin which
have fast reaction times and congestive properties and
- for spraying the resultant mixture, and to a spray gun.
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According to a first aspect of the invention
there is provided an apparatus for supplying and
dispensing a settable foam mixture, which includes
a high pressure propellant container which is a
metal bottle which, in use, contains a gas propellant;
a pair of low pressure plastic bottles one of
which, in use, contains resin and the other, in use,
contains catalyst;
a spray gun for mixing the resin and catalyst and
for spraying the resulting mixture;
connecting hoses for connecting the metal bottle to
each of the plastic containers and for connecting the
metal bottle and both plastic containers to the spray
gun; and
a valve means for controlling the flow of
propellant from the metal bottle to the plastic bottles
and from the metal bottle to the spray gun, and the flow
of resin and catalyst through the spray gun.
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Further according to this aspect of the
invention there is provided an apparatus as described
above, in which the metal bottle contains a gas
propellant which is at a relatively high pressure and
one plastic bottle contains resin and the other catalyst
and both plastic bottles are unpressurised.
The metal bottle may be at a supply pressure
of about 5 MPa.
~Further according to the invention there is
provided a portable apparatus for supplyinq and
dispensing a settable foam mixture which includes
a propellant container;
a propellant at a suitably high pressure contained
within the propellant container;
an unpressurised resin containeri
resin contained in the resin container;
an unpressurised catalyst containeri
catalyst contained in the catalyst container;
a spray gun;
a connecting means for connecting the propellant
container to the spray gun, the resin container and the
catalyst container;
connecting hoses connecting the resin and catalyst
container to the spray gun; and
a valve means between the propellant container and
the connecting means for supplying, in use, propellant
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to the resin and catalyst containers and the spray gun
at a reduced pressure.
The valve means may include a distribution
valve for controlling the supply of propellant, in use,
to the resin container, the,catalyst container and the
spray gun. The propellant container may be at a supply
pressure of about 5 MPa and the distribution valve may
be such that it supplies propellant to the resin
container , the catalyst container and the spray gun at
a distribution pressure, in use, which is much lower
than the supply pressure. Thus, the distribution
pressure may be in the region of 300 KPa.
The distribution valve may have a first
orifice which restricts the flow of gas from the
propellant container to provide the required drop in
pressure.
:
It will be appreciated that the distribution
valve will have three outlets, one of which is connected
to the spray gun, and the other two being connected to
the resin container and the catalyst container
respectively, by means of the connecting hoses.
It is further to be appreciated that the spray
- gun will operate at a pressure, known as the application
- pressure, as a result of the pressure of the propellant
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utilised by it. Thus, the apparatus may include an
application pressure controL means for controlling the
application pressure of propellant utilised within the
sE)ray gun.
The application pressure control means may
include a first orifice and a second orifice. The first
orifice may be located at the propellant container and
the second orifice may be spaced therefrom and may be
between the propellant container and the interior of the
spray gun. In the foam dispenser application the second
orifice may be located between the spray gun and the
distribution valve. Preferably, the second orifice is
located at the spray gun end of a hose connecting the
propellant container to the spray gun, or in a component
of the spray gun.
Those skilled in the art will appreciate that
the application pressure will be determined by the
balance of the mass flow rate through the first orifice
and that of the second orifice. Since both orifices
restrict the flow of the gas prop~llant, flow is choked
by both restrictions and the mass flow rate through each
is provided by the following equations:-
Mass flow rate =constant x area x upstream stagnation pressure
- . upstream stagnation sonic velocity.
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It will be appreciated that the gas propellant
is used to displace resin and catalyst from the bottles
to deliver the resin and catalyst to the spray gun.
I'hus, the mass flow rate through the second orifice is
equal to the mass flow rate through the first orifice
minus the rate of flow of displacing gas which is
required to displace the resin and catalyst from their
bottles. The rate of flow of displacing gas is
determined by the rate at which the reactants are
consumed, which in turn is a function of the application
pressure.
As the relationship between the application
pressure and supply pressure is strongly related to the
relationship between the areas of the orifices, the
ratio of the areas of the orifices may approximate the
desired ratio of supply pressure to application
pressure.
Further according to the invention, the
distribution valve may be non-reversible. Thus, once
the valve is operated to permit flow of propellant out
of the propellant container, it is not possible to
operate the valve to stop the flow of propellant from
the propellant container. Thus, in one embodiment, the
distribution valve may have a disc that is ruptured, to
permit flow of gas from the propellant container. A
piercing member may then be provided to pierce the disc
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when the apparatus is to be used. As a safety feature,
t:he disc may also be such that, if the pressure in the
propellant container exceeds a predetermined value, it
ruptures. Preferably, the first orifice is located
between the disc and the interior of the propellant
container, so that gas is released from the propellant
container in a controlled manner.
The distribution valve may further be such
that there is an unimpeded flow path from the disc to a
nipple whereby the valve is connected to the hose that
connects it to the spray gun. Further, the spray gun
may be such that there is no further valve means for
controlling the flow of gas from the distribution valve
and through the spray gun into the atmosphere. Thus, a
safety vent flow path is provided between the rupture
disc and atmosphere, that is always open, via the spray
gun, in the event that the disc should rupture because
the pressure in the propellant container exceeds the
predetermined safety value.
As a further feature, the piercing member may
be held in an inoperative position by a safety pin, such
that only when the safety pin is removed can the
piercing member be displaced into an operative position
in which it pierces the disc. The piercing member may
be manually displaceable or may be spring loaded.
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Still further, the distribution valve may have
communication openings through which the gas flows to
the resin and catalyst containers, these communication
openings being blocked by the piercing member when it is
in its inoperative position and being unblocked when the
piercing member is in its operative position. Thus, the
possibility of resin and catalyst coming into contact
with one another in the distribution valve or the
possibility of either entering the valve and blocking it
is minimised.
As a further safety feature, the distribution
valve may have a further disc which is located between
an interior chamber and the exterior and which is
designed to rupture if the distribution pressure within
the chamber exceeds a predetermined value that is
suitably larger than the intended distribution pressure.
Instead, the connecting hoses connecting the
distribution valve to the resin and catalyst containers
or the spray gun may be such that they burst if the
pressure exceeds the predetermined value.
Those skilled in the art will appreciate that
the reactants (the resin and catalyst) are in liquid
form and thus pressure losses in the hoses connecting
the resin and catalyst containers to the spray gun will
be proportional to the velocity of the liquid in the
hoses squared, the density of the liquids, the length of
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the hoses and a friction factor. As it is desirable
that the connecting hoses have the same length, pressure
losses are balanced and minimised by varying the
internal cross-sectional area of the hoses. Thus, the
connecting hoses between the resin and catalyst
containers and the spray gun have suitable internal
diameters in accordance with the required proportion of
reactants to be supplied to the spray gun and the
reactants are then supplied to the spray gun, in the
required proportion virtually independently of the
distribution pressure.
It will be appreciated that the spray gun has
a mixing chamber from which the mixture is sprayed. The
distance to which mixed material will be sprayed (the
projection distance) from the mixing chamber will be
determined by the pressure in the mixing chamber.
In an attempt to ensure that the mixing ratio
between the two reactants is maintained at a particular
desired value, restrictive ducts may be provided between
the mixing chamber and the hoses connecting the spray
gun to the plastic bottles. These restrictive ducts may
have suitable lengths and diameters so that there is, in
use, a substantial pressure drop across the ducts.
Instead of using ducts, suitable orifices may be
provided.
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The apparatus may particularly be used to
provide a phenolic foam, in which case the resin may be
phenol formaldehyde, and the catalyst may be a phenol
sl~lphonic acid. The gas propellant may be nitrogen or
air.
It will be appreciated that the propellant
container and the resin and catalyst containers may be
of any suitable size and shape and of any suitable
materials. In a particular embodiment, the resin and
catalyst containers are plastic bottles which may be
formed in one piece by blow moulding or from two bottle
parts, each of which is hollow and, together form the
bottle. The two bottle parts may be mated to one
another by means of a ring. The two bottle parts may be
identical and each bottle part may have a neck portion
so that the bottle is open at both ends. The ends may
then be closed with caps, each of which has a nipple
whereby the bottle may be connected to the hoses. The
bottle parts may be injection moulded or blow moulded
and they may be of high density polyethylene or
polypropylene.
Still further according to the invention there
is provided a spray gun which comprises two parts, a
first body part and a second part which defines a flow
directing portion, a mixing chamber and a nozzle.
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The parts may be secured together in a
suitable manner. Thus, they may be welded together, 7
they may be held together by a fastener such as a screw
or they may clip together. In the latter case the body
part may have a plurality of projecting legs with hooks
at their end, with the other part having passages
through which the legs may pass, the hooks thereof
engaging a flange portion of the second part.
The body part may define three straight
parallel supply passages through which catalyst, resin
and gas propellant pass, in use. These passages may
open out in a planar surface which mates with a cavity
in the second part which defines the flow directing
portion. This cavity may have two spaced parallel walls
and two angled side walls that are also rounded and may
open into a substantially cylindrical passage in which
there are static mixing formations. The cylindrical
passage may have at its free end, ie. the end remote
from the cavity, a restriction which opens out into an
exit section. The r~estriction should be smooth and have
a converging half-angle in the order of 10 to 30 to
minimise the possibility of an entrance recirculation
bubble being formed,in use, which could induce clogging.
The cylindrical passage may constitute the
mixing chamber. In use, two streams of reactants are
directed into the cylindrical passage by the angled side
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walls, and they impinge on one another in a first part
of the passage, and thus mix with one another.
Two transverse valve members may be provided
in two of the supply passages to control the flow of
resin and catalyst. These valve members may be pivotal
by means of an operating handle. Further, a nipple
member may be provided for the third passage, which has
a restricted opening defined therein. Thus, unless the
gun gets clogged, there is a free flow path for the gas
propellant through the gun.
By means of the invention, a
portable phenolic foam dispenser is provided that is
cheap, reliable and safe.
The invention is now described, by way of
example, with reference to the accompanying drawings, in
which:-
Figure 1 shows a logic diagram of a portable
. .
apparatus for dispensing a phenolic foam, in accordancewith the invention;
Figure 2 shows a plan view of a spray gun of the
apparatus;
Figure 3 shows a side view of the spray gun;
Figure 4 shows a sectioned view of a body part of
the spray gun;
Figure 5 shows a sectioned view of a nozzle part of
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the spray gun;
Figure 6 shows a sectioned view of a pressure
ve!ssel assembly of the apparatus;
Figure 7 shows a longitudinally sectioned view of
an upper body of a distribution valve used with the
pressure vessel;
Figure 8 shows a sectioned view of the upper body
along line VIII-VIII therein;
Figure 9 shows a longitudinally sectioned view of
a lower body of the distribution valve;
Figure 10 shows a sectioned view of a reactant
vessel assembly of the apparatus; and
Figure 11 shows schematically how the apparatus is
stored in a container.
Referring to Figure 1, a portable apparatus
for dispensing a phenolic foam is designated generally
by reference numeral 10. Generally, the apparatus
comprises a propellant container in the form of a metal
bottle 12 which contains nitrogen or air propellant 14
at a pressure of about 5 MPa, a resin container in the
form of a plastic bottle 16 which has a volume of 8
litres and contains resin 18, a catalyst container in
the form of a plastic bottle 20 which has a volume of
2,5 litres and contains catalyst 22, a distribution
valve 24 which controls the distribution of propellant,
a spray gun 26, a connecting hose 28 connecting the
distribution valve 24 to the resin bottle 16, a hose 30
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connecting the distribution valve 24 to the catalyst
bottle 20, a hose 32 connecting the distribution valve
24 to the spray gun 26, a hose 34 connecting the resin
bottle 16 to the spray gun 26 and a hose 36 connecting
the catalyst bottle 20 to the spray gun 26.
In the particular embodiment of the apparatus
that is described, the resin is phenol formaldehyde and
the catalyst is phenol sulphonic acid. The resin has a
viscosity of 450 centipo1se and a density of 1,2 kg per
litre. The catalys~ has a viscosity of 200 centipoise
and a density of 1,4 kg per litre. As indicated above,
the propellant bottle 12 provides propellant at a supply
pressure of 5 Mpa. The distribution valve 24 has a
first orifice 38 which has a diameter of 0.35 mm which
decreases the pressure of the propellant to a
distribution value of approximately 300 Kpa. The
propellant is retained in the bottle 12 by means of a
rupturable disc 40 which is ruptured when the apparatus
10 is to be used, by means of a piercing pin 42. The
disc 40 is of hard brass having a thickness of about
0,05 mm. At all times there is an open flow path
between the interior of the distribution valve 24 and
the connecting hose 32 which connects the distribution
valve 24 to the spray gun 26. The pin 42 is held in an
inoperable position by a safety pin 44.
It is to be appreciated that the spray gun 26
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will operate at a pressure, known as the application
pressure, as a result of the pressure of the propellant
14 passing therethrough. Thus, the application pressure
utilised within the spray gun 26 is also controlled by
the first orifice 38 and a second orifice 52 in the
spray gun 26, which has a diameter of 0,7 mm.
As will be seen below, when the piercing pin
42 is in its inoperative position, there is no
communication between the connecting hoses 28 and 30 or
between either of the hoses 28 and 30 and the interior
of the distribution valve 24. Such communication can
only take place when the piercing pin 42 is displaced to
its operative position. It is also to be noted that the
bottles 16 and 20 are normally not pressurised and that
there is an open flow path between the hose 28 and the
bottle 16, between the bottle 16 and the hose 34,
between the hose 30 and the bottle 20 and between the
bottle 20 and the hose 36. It will thus be appreciated,
that when the safety pin 44 is removed and the disc 40
ruptured by the piercing pin 42, propellant 14 is
supplied to the resin bottle 16 and the catalyst bottle
20 at a distribution pressure of approximately 300 Kpa.
The connecting hoses 28, 30 and 32 are of a
suitable construction so that they will burst if the
pressure therein increases significantly above 300 Kpa.
It will further be understood that the internal cross-
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sectional areas of the hoses 28, 30 and 32 are not
critical and must merely be suitably large to permit
flow of propellant therethrough without any significant
pressure drop.
On the other hand, the length and internal
cross-sectional areas of the connecting hoses 34 and 36
are critical and are used to control the rate of flow of
resin 18 and catalyst 22. It is desired that the flow
rate of resin 18 be three times that of the catalyst 22
and it is also desired that the hoses 34 and 36 be of
equal length. Thus, the hoses 34 and 36 have a length
of 3 meters and the resin hose 34 has an internal
diameter of 16 mm and the catalyst hose 36 has an
internal diameter o~ 10 mm.
It will be appreciated that the distribution
valve 24 is non-reversible, in the sense that once the
disc 40 has been ruptured it is not possible to close
off the bottle 12 and the propellant 14 therein will
discharge.
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Turning now to the spray gun 26 it will be
seen that it has an on-off valve 46 for controlling flow
of resin 18 and a further on-off valve 48 for
~ controlling flow of catalyst 22. The valves 46 and 48
; are operated together by means of a handle 50. The gun
: 26 further has the orifice 52 which, as explained above,
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controls the application pressure together with the
orifice 38. The spray gun 26 also has a resin duct 54
and a catalyst duct 56 for controlling the flow of resin
18 and catalyst 22. The ducts 54 and 56 both have a
length of 30 mm, with the catalyst duct having an
internal diameter of 2,5 mm and the resin duct having an
internal diameter of 4,8 mm.
~ The spray gun 26 has a nozzle part.58 and it
will be seen that the propellant 14 is supplied through
.a straight passage 60 that is in line with and central
to the nozzle part 58. It will be noted that the ducts
54 and 56 are also straight, with the duct 54 being on
one side of the passage 60 and the duct 56 being on the
other side. As is e~plained below, flow of resin 18 and
catalyst 22 are deflected inwardly after they leave the
ducts 54 and 56.
The nozzle portion 58 has a mixing chamber 62
in which there is a static mixer 64. The nozzle part 58
` has an exit 66 with a restriction 68 between the exit 66
and the static mixer 64. The restriction is smooth and
has a converging half-angle of 22,5.
It will thus be appreciated, that when the
apparatus 10 is to be used, the safety pin 44 is
removed, the piercing pin 42 is manually displaced to
pierce the disc 40 and the handle 50 is displaced to
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open the valves 46 and 48. It is not possible for the
operator to vary or control the pressure or flow of
propellant. The resin 18 and catalyst 22 are displaced
from their bottles 16 and 20 to the spray gun 26 where
they are mixed and the mixture is sprayed from the spray
gun 26 as directed by the operator. Although it is
possible for the operator to close the valves 46 and 48
by operating the handle S0, this will not prevent
propellant from venting through the spray gun 26 and, in
the event that the operator should try and close off the
exit 66 with his thumb or the like, there will be a
build up of pressure in the hoses 28, 30 and 32 which
will cause one of them to rupture.
The various components of the apparatus 10 are
now described in more detail.
Referring to Figures 2, 3, 4 and 5, the spray
gun 26 and parts thereof are shown. Referring initially
to Figures 2 and 3, the handle 50 and the nozzle part S8
are shown. The gun 26 also has a body part 70 with
three nipples, two of which , 72 and 74, being visible
in Figure 2. The resin hose 34 is connected to the
nipples 72 and the catalyst hose 36 is connected to the
nipple 74. The nipple 72 and 74 have sizes which
correspond with the internal diameters of the hoses 34
and 36 so that the hoses 34 and 36 cannot be connected
to the wrong nipples 72 or 74 which in turn ensures that
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resin is supplied to the duct 54 and catalyst to the
duct 56. As shown in Figure 3, the operating handle S0
is pivoted ~rom the inoperative position shown in solid
lines, through 90 to the operative position shown in
dotted lines. When the handle 50 is pivoted in this
manner, two spindles are rotated. One of the spindles
76 is shown. When the spindles are rotated, a
transverse bore in each spindle is rotated to be in line
between the nipple 72, 74 and the duct 54, 56
respectively. When the spindles are in their
inoperative position, they block the flow path between
the nipples 72, 74 and the ducts 54, 56 respectively.
Referring to Figure 4, the body part 70 is
shown in more detail. It will be noted that the body
part 70 is made of high density polyethylene with 15%
glass fibre reinforcing. The nipples 72 and 74 are
shown in Figure 4 together with the third nipple 78 to
which the hose 32 is connected. It will be seen that
the orifice 52 is located in the nipple 78 with the
passage 60 being in line therewith. The ducts 54 and 56
are also shown and, as indicated above, the ducts 54 and
56 and the passage 60 are all straight and parallel to
one another with the passage 60 being between the ducts
54 and 56. As indicated above, the ducts 54 and 56 and
the passage 60 open out in a planar face 80.
Referring to Figure 5, the nozzle part 58 is
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shown. The nozzle part 58 is also of hiqh density
polyethylene with 15% glass reinforcing. As seen in
Figure 5, the nozzle part 58 has a frusto-conical
portion 82 and a tubular portion 84.
The frusto-conical portion 82 has a recess
defined by lips 86 with the end of the body part 70
defined by the planar face 80 being snugly received
therein. The body part 70 and nozzle part S8 are
secured together by means of an adhesive, welding or the
like.
The frusto-conical portion 82 has two opposed
parallel planar walls (one of which 88 is designated)
and two angled rounded walls 90 and 92 to define a
cavity. It will be appreciated that the angled wall 90
is aligned with the duct 54 and the other angled wall 92
is aligned with the duct 56 so that streams of resin 18
and catalyst 22 issuing from the ducts 54 and 56 are
deflected by the angled walls 90 and 92 towards each
other and towards the tubular portion 84.
The tubular portion 84 has the mixing chamber
62 which is circular cylindrlcal being defined by a
cylindrical wall 94. It is to be noted that there is
fairly sharp transition between the angled walls 90 and
92 and the cylindrical wall 94 respectively. Thus, ln
use, the deflected streams of resin 18 and catalyst 22
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impinge on one another and with a stream of propellant
14 which flows from the passage 60 so that they mix well
together, with further mixing being provided by the
static mixer 64 (which is an insert and is not shown in
Figure 5). Further, the resin 18 and catalyst 22 react
with one another in the mixing chamber 62 and the
mixture, with propellant bubbles therein, is discharged
from the exit 66 as a foam.
- Figures 6, 7, 8 and 9 are now referred to.
Referring initially to Figure 6, the metal bottle 12
containing the propellant 14 and the distribution valve
Z4 are designated therein. The bottle 12 is o~ an
aluminium alloy.
The distribution valve 24 includes, as
discussed earlier, the disc 40, the piercing pin 42 and
the safety pin 44. The disc 40 is held between a lower
valve body 96 and a disc holder 98. There is an O-ring
100 between the disc holder 98 and the lower valve body
96 the purpose of which is explained below. The lower
valve body 96 and t:he disc holder 98 are both of brass.
It will be noted that the lower valve body 96
has an external screw-thread 102 by means of which it is
screwed into the neck 103 of the bottle 12 and it also
has an internal screw-thread 104 with the disc holder 98
having a complementary external screw-thread.
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An upper valve body 106, which carries the
piercing pin 42, is screwed into the disc holder 98, the
disc holder 98 having an internal screw-thread and the
upper valve body 106 having a complementary external
screw thread.
As is seen in Figure 6, the piercing pin 42
has a lower sharpened portion 108 with a slot 110
therein and a central portion 112 which is slightly
larger than the lower portion 108. Finally, the
piercing pin 42 has an upper portion 114 which is
smaller than the central portion 112, there being a
shoulder 116 between them. The safety pin 44 passes
through a bore in the upper portion 114 and the upper
portion 114 carries a knob 118. The pin 42 is also of
high density polyethylene with 15~ glass reinforcing.
Referring in addition to Figures 7 and 8, it
will be seen that the upper body 106 has two nipples 120
and 122 for the hoses 28 and 30 and a socket 124 into
which an insert (not shown) is inserted, the insert
having a further nipple to which the hose 32 is
connected. The upper body 106 has an internal bore 126
which is transverse to the nipples 120 and 122 and the
socket 124. The bore 126 has an internal step 128 which
is slightly inward of the bottom edge of the socket 124.
A communication opening 130 is provided between the bore
126 and the socket 124 at the step 128 so that there is
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an unimpeded flow path between the bore 126 and the
socket 124 even when the piercing pin 42 is in its
inoperative position as shown in Figure 6. Passages 132
in the nipples 120 and 122 open out in a central part
134 of the bore 126, above the step 128. It will be
understood that the central portion 112 of the pin 42 is
located in the central part 134 of the bore 126 when the~
pin 42 is in its inoperative position. As the central
portion 112 of the pin 42 is a snug fit in the central
part 134 of the bore 126, there is no fluid
communication between the passages 132 and between each
passage 132 and a lower part 136 of the bore 126. It
will further be appreciated, that when the pin 42 is
displaced into its operative position in which it
pierces the disc 40, the central portion 112 of the pin
42 passes into the lower part 136 of the borè 126 and
the shoulder 116 together with the step 128 impede
return of the central portion 112 of the pin 42 into the
central part 134 of the bore 126, which would result in
blocking of the passages 132. As seen in Figure 6, the
pin 42 has a short groove 138 at the upper end of the
central portion 112 to provide a flow path for
propellant into the passages 132 even if the shoulder
116 abuts the step 128.
Referring to Figure 10 the resin bottle 16 is
shown. The bottle 16 is of high density polyethylene
and is formed from two identical parts 140 which mate
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together and are welded together at mating ends 142.
1'he parts 140 each have a neck 144 that is externally
screw-threaded. One end is closed by a cap 146 which has
an integral nipple 148 that is connected, in use, to the
hose 34. The other end is closed by a cap 150 and a
separate nipple 152 which, in use, is connected to the
hose 28. As indicated above, the resin bottle 16 has a
volume of 8 litres.
.. .
. The catalyst bottle 20 is similar in
construction to the resin bottle 16, except that the two
parts 140 are smaller and one end is closed with a cap
similar to cap 146 but with a nipple that has a size
complementary to the internal diameter of the hose 36.
Further, as indicated above, the catalyst bottle 20 has
a capacity of 2,5 litres.
Referring finally to Figure 11, it is shown
that the apparatus 10 also includes a case 154 which has
carrying straps 156. The bottles 12, 16 and 20, the
.:
various hoses and the spray gun 26 being stored in the
case 154. It will be noted that the bottles 16 and are
stored in an upright manner, with their nipples 152 to
which the hoses 28 and 30 are connected being on top, so
that the propellant 14 displaces the resin 18 and
catalyst 22 out of the other, bottom ends of the bottles
16 and 20.
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It will be noted that the bottle 12 is filled
~ith propellant in the following manner. The lower body
96 is screwed into the neck 103 of the bottle 12, the
disc 40 is placed in position and the disc holder 98 is
screwed into the lower body 96. However, the disc holder
98 is not screwed down tightly and a suitable connector
(not shown) connected to a supply of nitrogen or air
under pressure, is screwed into the disc holder 98.
Nitrogen is supplied, and flows past the disc 40 into
the bottle 12. When the bottle 12 is filled to the
required pressure, the disc holder 98 is screwed down
tightly thereby gripping the disc 40 in a sealing
manner. The connector is removed and the upper body 106,
with the piercing pin 42 therein is screwed into the
disc holder 98.
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