Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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"Apparatus for feeding a liquid to an applicator"
This invention relates to apparatus for
feeding a liquid to an applicator, and in particular,
to apparatus primarily intended for painting.
For many years it has been common practice
to apply a liquid to a surface using a brush, the
brush first being dipped in a reservoir of the
liquid and then wiped over the surface to be coated.
For relatively large surf~ce areas, rollers rather
than brushes are used, the roller also being dipped
in a reservoir of the liquid and then rolled across
the surface to be coated. As an alternative to the
use of a brush or roller, a pad has, in more recent
times, sometimes been used: again, the pad is dipped
in a reservoir of the liquid and then wiped across
the surface to be coated.
The mode of application described above is
unduly time consuming because of the necessity to
dip the applicator (brush, roller or pad), in the
liquid at frequent intervals in order to replenish
the supply of liquid on the applicator. This is a
particular problem when the user is standing on a
ladder or a pair of steps which is frequently the
case, for example when painting a ceiling. To
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mitigate this problem it has been proposed in the
case of rollers to increase the liquid capacity
of the roller by providing it with its own small
liquid reservoir' this attempted solution, however,
considerably increases the weight of the roller
making it very tiring to use.
From time to time throughout this century
it has been proposed to provide the liquid
applicator with a connection via a length of tube
to a reservoir of liquid and to feed the liquid
from the reservoir to the applicator by pressure
generated by a pump. This arrangement has the
considerable advantage over the conventional
arrangements described above that a user does not
continually have to replenish the liqu,id on the
applicator nor does the applicator have to be
excessively heavy. These proposed pressurised
arrangements have not, however, proved satisfactory.
If the reservoir of liquid and its associated
pump is placed on the ground during application
of the liquid then a long length of tubing is
required between the reservoir and the applicator
and this can impede the user. If, on the other
hand, the reservoir and pump are carried by the
user then this impedes the user during painting
and is tiring as a result of the weight of the
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reservoir and pump assembly.
It is known to dispense a liquid from a
container using a small capsule of pressurized
gas. For example, soda syphons have ~een available
for some years operating on this principle.
National Can Co~poration have disclosed a paint
apparatus in which a container of paint is pressure
fed by pressurized gas from a capsule to a roller;
in operation the container is rested on the ground
and a long length of tubing connected between the
container and the roller to allow a user to paint
a surface, holding the roller alone. An illustra-
tion of this proposed apparatus appeared on pages
30A and 31A of the Journal.of Paint Technology Vol,
40, No. 521, June 1968. Liquid containers
pressurized by capsules of gas are also described
in United States Patents Nos. 3 352 457 and
3 558 010 assigned to National Can Corporation.
The painting apparatus proposed by National
Can Corporation still suffers various drawbacks.
The use of a long iength of tubing can impede the
user as already mentioned and also this apparatus,
as well as the pressurized arrangements already
described, is difficult to clean and messy to use.
If the painting apparatus includes its own pressure
vessel for containing the paint, the paint must
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first be poured into this vessel and then
after painting, any paint left in the vessel must
be poured out and the vessel, in addition to all
the rest of the apparatus, must be cleaned. The
time saved during painting with the apparatus may-
thus be consumed in extra time spent preparing the
apparatus for use and cleaning the apparatus after
use.
To some extent, the cleaning operation can
be reduced by supplying the paint in its own
pressure vessel to which the pressurizing arrange-
ment is then directly attached, since this avoids
the need to clean the vessel after use. ~owever,
in this case the vessel
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containing the paint must be specially constructed
both to be sure of withstsnding the pressure contained
in the vessel during u~e and to receive the pressuri-
zing arrangement. This greatly increase~ the cost o~ the paint vessel over a conventional paint can.
It is an ob~ect o~ the invention to pr~vide
sn apparatu~ ~or ~eeding a liquid to an applicator,
that mitigates at lea~t ~ome of the disadvantages
described above.
According to a ~irst aspect oi the invention
there is provided an apparatu~ for feeding liquid
under pressure, the apparatus including:
a vessel,
a liquid container received, in use, ~ithin the5 ~essel,
a pressurizing assembly including a housing ~or
receiving a capsule of lique~ied or pressurized gas and
pres~ure reducing means,
a ~irat ilu~d path e~tending from the high pressure
side of the pressure reducing means ~or communicating
with the outlet oi a capsule inserted, in use, in the
housing,
a second ~luid path e~tendin~ irom the low
pressure side of the pressure reducing means into the5 container,
a hand-held applicator ~or coati~g a surface
with liquid, and
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a ~eed conduit, including a ~lexible tube
e~tending between the vessel and ~he applicator, for
tran~ferring liquid from the container to the applicator.
~ he use of a small cap~ule o~ liquefied or
pre~urized gas to provide the pressure in the container
provides an e~tremely compact, light weight a~d conve~ient
pre~surizing arra~gement.
The provision of a contaiGer withia the ~essel
is an important feature, The liquid to be ~ed to an
applicator can be sold in the container which, 6ince
it is, in use, disposed in the outer vessel does not
have to be sure of withstanding pressure a~d can be
oi aimple con~truction. ~ter the liquid has been
fed ~rom the container, the latter can be thrown a~ay
and the vessel doeæ not ha~e to be cleaned,
The top oi the container may be substantially
closed; the feed conduit may pass through the top of
the ~e~sel and the top of the co~ainer to a location
ad~acent the bottom o~ the container; the feed co~d~it
may pass through the container in such a way that the
junction between the cortainer wall and the ~eed conduit
i8 closed over. This inhibits liquid spilling ~rom
the container into the ~essel.
A small hole may be pro~ided in the top o~ the
container to allow gas to flow between the container and
the vessel to equalize the pressure therein. Alter~ati~ely
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a sllt may be provided in the top o~ the contalner.
~ he co~tainer may al80 include a clo~ure member
which can be secured over the top of the container when
the container i~ not in use to 8eal the oontainer. Thls
preserves the l~quid in the container when it i8 not
i~ use and prevents spillage.
~ he bottom of the container may have a w~ll
~ormed therein the end o~ the feed conduit being within
the ~ell.
The pressure reducing mean~ may be adjustable
to vary the pressure, in use, in the vesselr ~he range
oi pressure variation may be limited.
The pres6ure reducing mean~ may include a valv~
member mounted i~ a passage providing communication
bet~een the fir~t fluid path a~d the second fluld path,
the valve member being movable between a first position
in whicn the passage i9 closed and a second position i~
which the passage is open, the val~e member being resilient-
1~ biased, in use, into the first position, and a pistcn
or diaphragm co-operable with the valYe member and movable
away irom one position in which the valve member is held in
the second positio~ by the piston or diaphragm to another
position in which the valve member assumes its ~irst
position, the piston or diaphragm being biased to said
one position by a spring and being biased awag from said
one position to another po~ition by the pres~ure of gas
on the low pressure side o~ the pressure reducing means.
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~he bias force o~ the spring acting on the plston
or diap~ragm may be adjustable, whereb~ the pressure oi
gas required to move the piston or diaphragm away from
sald one position to another position is ad~ustable.
In u~e, a capsule oi liquefied or pressurized
gas i~ located ~n the hou~ing. The ga~ ma~ be carbon
dio~ide or nitrou~ o~ide or any gas which do~s not ha~e
too substantial a deleterious effect on the liquids
with which i~ will come into contact.
The vessel ma~ oomprise a body part and a lid.
The lid mag be mou~ted o~ the body psrt o~ the
vessel such that i~ e~cess pressure develops between
the lid and the body part the ve~sel is ~ented between
the lid and the body part.
A pipe may be provided through the lid to provide
the ieed conduit for transierring liquid ~rom the veseel
to ~n applicator.
~he pre~surizing assembly may be mounted on
the lid.
The vessel may be arranged to be carried b~ a
user without using his hands. In this case the user
ha~ both hands ~ree to operate the applicator or perform
an~ other function.
A handle may be mounted on the vessel, ~he handle
may be of inverted rectangular '~' shape.
A clip may be provided on the vessel for attaching
the vessel to a belt, to enable a user to suspend the
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vessel ~rom hi~ wai~t.
A pre~sure relief valve may be mounted in a wall
of the vessel. The pre~uxe relief valve m~y be mounted
on the lld o~ the vessel. An actuating arrang~ment ~ay be
provided for actuating the pres~ure relief valve each time
the apparatus is a~embled for u~e. Such a~ arrange-
ment sa~eguards against the po~slbility o~ the pre~sure
relie~ valve becoming ~tuck.
Manuall~ operable me~n~ mag be provided for venting
the pre~urized gas in the vessel to return the pres~ure
in the ves~el to atmospheric pressure~ ~he venting means
may be provided by the pre~ure reducing means. ~lter-
natively the venting means may be provided by ~ome other
arrangement, ~or e~ample, by the pressure relief valve~
lhe applicator ma~, ior e~ample, be a pad, a
roller or a brush. ~he length o~ fle~ible tube is
preferably between one and two metres long. The tube
must be long enough to allow a u~er full range o~ move-
ment o~ the applicator but exce~sive length is unde~irable
- 20 as it m~y impede the user7 increa~es the pressure required
to ~eed the liquid and adds to the length o~ tube to be
cleaned. In a particular e~ample o~ the ~nvention the
tube i8 one and a quarter metres long. ~he applicator
i8 preierably provided with a valve ~or controlling the
ilow of liquid along the tube.
~ he ~eed conduit may compri~e a pipe in the vessel
and a ile~ible tube e~tending bet~een the pipe and the
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applicator, one end of the tube bei~g ~itted over one
end of the pipe and the ~unctlon of the tube and the
pipe being a tight fit in an internal recess o~ the
vessel, the tube pa~sing through a bore extending between
the recess and the exterior of the vessel.
According to another aspect o~ the invention
there i8 provided ~n apparatus ~or applying paint or the
like to a surface, the apparatu~ i~cluding:
a vessel,
a hand-held applicator ior applying paint or
the like to a surface,
a fle~lble tube e~tending between the ~essel
and the appllrator,
a substantially closed container received, in
use, within the ve~sel and containiDg pai~t or the
like,
a pressurizing as~embly including a ho~sing for
receiving a capsule o~ liqueiled or pres~urized ga8
and pressure reducing means,
a rirst n uid path e~tending irom the high
pressure side of the pressure reducing means ror
communicating with the outlet of a capsule in~erted,
i~ use, in the housing,
a second fluid path extending irom the low
pressure side of the pressure reducing means into the
container,
means associated with the container for allowing
ilow oi gas between the interior of the ve~el e~ternally
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oi the co~tainer and the interior of the container,
but inhibit1ng flow of paint or the like from the con-
tainer into the interior of the ~es~el e~ternally of
the container, and
a ~eed conduit passing into the vessel from the
e~terior thereo~ and communicating with the interlor
o~ the container for tran~ferrlng paint or the like
from the container to the applicator.
Said mean~ associated with the container may
comprise a small opening 1~ the top of the contalner~
~ he apparatus may ~urther ~nclude one or more
interengaging ~ormation~ on the esternal surface of the
container and the internal sur~ace of the vessel-ior
inhibiting the insertion in the vessel of an unsuited
container.
~ccording to another aspect of the invention
there i8 provided an apparatus for applying paint or
the llke to a sur~ace, the apparatus including:
a vessel,
an applicator for applying paint or the li~e
to a suriace,
. ~ ~le~ible tube e~tending between the ves~el and
the applicator,
a ~ubstantiall~ closed container received, in
uee, within the vessel, and containing paint or the
like,
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a pressurizing assembly ~upported on the ~e~sel
and including a housing for receiYing a capsule of
lique~ied or pressurized gas and pressure reduci~g
means,
a ~irst ~luid path e~tending from the high
pres~urs side Or the pressure reducing means for communi-
cating ~ith the outlet OI a capsule in~erted, in u~e,
in the hou~ing,
a ~econd fluid path extendi~g ~rom the low
pre~sure side of the pre~sure reducing méans into the
container through a small opening in the container wall,
and
a feed conduit connected to the fle~ible tube
and passing through the top o~ the conta~ner to a location
ad~acent the bottom o~ the contai~er~
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By way of example, an apparatus for feeding a liquid to an applicator
will now be described with reference to the accompanying drawings, in which:
Figure 1 i5 a side view of the apparatus.
Figure 2 i5 a sectional side view of part of the apparatus;
Figure 2A is a side view of a closure member associated with a
component shown in Figure 2,
Figure 3 is a sectional side view of another part of the apparatus,
Figure 4 is a sectional side view of a switch included in the apparatus,
Figure S is a sectional side view of a small part of the apparatus
illustrating a modification which may be made to the apparatus of Figure 2,
Figure 6 is a sectional side view of another small part of the
apparatus illustrating another modification which may be made to the apparatus
of Figure 2, and
Figure 7 is a sectional side view of a pressure indicator which may
be incorporated in the apparatus.
Figure 1 shows a vessel 1 of circular cross-section having a body 4
and a lid 5 in which is received a container 2 containing paint 16. The
vessel 1 and container 2 are made of a plastics material. A feed conduit
for the paint is provided
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by a pipe 3 extending from the centre of the lid
5 of the vessel, towards the bottom of the
container. The container 2 has a well 6 formed
in its base and the pipe 3 extends into this well.
A flexible tube 7 which is one and a quarter metres
long is attached to the end of the pipe 3 and leads
to a paint pad 8.
~ pressurizing assembly 9 including a capsule
of liquefied gas and a reduction valve (not shown
in Figure 1) is mounted eccentrically on the lid
5 and pressurizes the vessel 1 and the inside and
outside of the container 2. Also mounted on the
lid 5 is a safety valve (not shown in Figure 1) and
a handle 10 which has two upright limbs extending
from the diametrically opposite parts of the
periphery of the lid 5 and an integral cross-
member connecting the tops of the upright limbs.
Thus, the handle 10 is of inverted rectangular 'U'
shape.
Referring now to Figure 2, which shows the
upper portion of the vessel 1 and the container 2
but does not show the pressurizing assembly 9, the
lid 5 is screwed onto the body 4 of the vessel and
an '0' ring 60 seals the junction between these
parts. The lid 5 has an aperture in which is
received a safety valve 11 in the form of a
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pressure relief valve. The safety valve 11
comprises a grommet 12 and a valve member 13
received in the grommet 12. In its normal un-
operated position shown in Figure 2 the valve
member seals the aperture in the lid 5.
The top of the container 2 is defined by a
lid 170 permanently fitted to the container 2 and
defining a diaphragm 14 which has a central aperture
through which the pipe 3 extends as a close fit
and a small hole 15 which ensures equalisation of
pressure between the inside and outside of the
container but which is not sufficiently large to
allow paint to pass through the hole except at a
very slow rate. The diaphragm 14 is inset from the
top of the container defining a recess above the
diaphragm which receives a sealing plug 80 (Figure
2A) when the container 2 is not in use to seal the
container. While the part 14 is ~eferred to as a
"diaphragm", it should be understood that this
part may be of rigid construction
The lid 5 has a central cylindrical recess
within which the tube 7 is secured to the pipe 3.
To assemble the apparatus the end of the tube 7 is
passed through the lid 5 and fitted over the pipe
3 The tube 7 is then pulled back through the lid
5 drawing the end of the pipe 3 into the recess.
1 1 55802
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The assembly of the pipe 3 and tube 7 are a tight
fit in the recess and seal the junction of the tube
7 and the lid 5~
Referring now to Figure 3 which shows the
pressurising assembly 9, the assembly has a body
18 including a screw threaded boss 19 which passes
through an aperture in the lid S of the vessel 1
and to which a nut is secured to retain the assembly
9 on the lid 5. One or more pegs 89 on the base
of the body 18 engage in corres~onding recesses
(not shown) in the top of the lid 5 and locate the
assembly 9 on the lid 5. The assembly 9 includes
a housing 20 for receiving a capsule 24 of liquid
carbon dioxide. A capsule piercing member 21
including a piercer 42 is received in the body 18
and an 'O' ring 23 seals the interface of the
piercing member 21 and the body 18. T~e end of the
piercing member 21 adjacent the housing 20 has a
bore sized to receive the neck of the capsule 24
and an 'O' ring 45 is seated in the bore to seal
the interface of the capsule neck and the bore.
To insert a capsule 24 into the assembly 9 the
housing 20 is first unscrewed. The capsule 24 is
then placed in the housing 20 and the housin~ 20
brought into position to be screwed onto the body
18. At this stage, the neck of the capsule 24 is
1 1558~2
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in sealing engagement with the piercing member 21
but the capsule is to the left of the position shown
in Figure 3 so that the capsule is not yet pierced.
As the housing 20 is now screwed onto the body 18,
the housing drives the capsule onto the piercer 42
and the capsule is pierced allowing gas to flow along
a fluid path from the capsule through the piercing
member 21 into a chamber 25 defined by the piercing
member 21 and a valve housing 22 which is screwed
onto the piercing member and whose interface with
the piercing member is sealed by an '0' ring 46.
The chamber 25 is the high pressure chamber of an
adjustable pressure reducing valve assembly which
will now be described.
The valve housing 22 slidably receives a
valve member 26 which has a closure disc 27 at one
end which is in the chamber 25 and a head 28 at the
housing 22 and is resiliently biased by a weak
spring 34 against the seat. The right hand end
(as seen in Figure 3) of the body 18 has a bore 30
in which a piston 29 is slidingly received, an '0'
ring 41 being provided around the piston 29 to seal
the interface of the piston 29 and the bore 30. The
bore 30 is closed by a cap assembly 31 screwed onto
the exterior of khe body 18~ The piston 29 is
inwardly biased by a compression spring 32 extending
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between the piston and the cap assembly 31. In the
position shown in Figure 3 the head 28 of the valve
member 26 abuts the piston 29. A chamber 33 is
defined between the valve housing 22 and the piston
29, this chamber communicates with a duct 14 which
extends through the boss 19 of the body 18 and thus
provides a fluid path between the veseel 1 and the
chamber 33.
The cap assembly 31 consists of an operating
member 81 screw-threaded on the body 18, an adjusting
member 82 screwed into an axial passage of the member
81 so that the relative axial position of the members
81 and 82 can be adjusted by screwing the member 82
into the member 81, and a closure member 83 which
fits over the outer end of the axial passage in
the member 81 and which conceals the adjusting
member 82 and al.so locks the adjusting m~mber 82 to
the operating member 81. The spring 32 extends
between the piston 29 and the adjusting member 82,
and the maximum separation of the piston 29 and the
adjusting member 82 is limited by the engagement
of an anchor 84 extending from the piston 29 with
the adjusting member 82.
Before insertion of the capsule 24, with the
pressure in the vessel 1 atmospheric and with the
valve set to provide a finite gauge pressure in the
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vessel 1, the pressure in chamber 33 is atmospheric
so that the piston abuts the end face of the bore
30 nnd the valve member 26 is pressed against the
action of the spring 34 to an open position in which
the closure disc 27 is spaced from the seat on the
valve housing 22. Upon insertion of the capsule 24,
pressurized gas passes through the chamber 25 and
the chamber 33 into the vessel 1. As the pressure
in the chamber 33 then increases to above atmospheric
the piston 29 is pressed outwards against the bias
of the spring 32 to a position in which the force
of the pressure over the face of the piston sub-
stantially equals the force of the spring 32 (there
is also a force applied to the piston by the spring
34 but this is so small as to ~e insignificant).
The pressure continues to increase until the piston
reaches the position shown in Figure 3 at which
stage the closure disc 27 abuts the valve seat of
the valve housing 22 and the flow of gas from the
capsule stops.
When the pressure in the vessel 1 drops, for
example as a result of paint being fed from the
container 2, the force exerted by the spring 32 on
the piston 29 will overcome the force of the gas
pressure and the valve member 26 will be pressed
into the open position. Thus the piston 29 and
802
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spring 32 regulate the pressure in the vessel 1.
During normal operation the operating member 81 is
in the position shown in Figure 3 The pressure
which this produces in the vessel 1 is dependant
upon the axial position of the adjusting member 82
and this position is set in the factory to produce
the desired pressure and the closure member 83 then
positioned over the end of the adjusting member.
For example, screwing the adjusting member 82 towards
the piston 29 increases the compression of the spring
32 and therefore increases the pressure at which
the valve member 26 is moved into the closed position.
In order to set the position to which a user screws
the operating member 81, a flange 35 is provided
around the periphery of the member 81 and this flange
engages a projection 36 on the lid 5 of the vessel
1 when the member 81 is screwed to the pressurized
position.
Another projection 37 is provided on the
lid 5 and engagement of the flange 35 with this
projection 37 limits the outward movement of the
member 81 and prevents the cap assembly being re-
moved after the pressurizing assembly 9 is mounted
on the lid 5~
In the event of the valve member 26 becoming
stuck in the open position, the pressure on the
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piston 29 gradually increases and the piston is moved
outwards against the bias of the spring 32. The
bore 30 however is grooved at 38 so that once the
piston reaches the ends of the grooves compressed
gas can pass around the side of the piston and out
to atmosphere through another groove provided along
the screw threads of the member 81 and the body 18.
As an alternative to providing the groove, the
member 81 may be apertured.
When the operating member 81 is unscrewed so
that the flange 35 abuts the projection 37, the head
84 extending from the piston 29 is compelled, by
engagement with the adjusting member 82, to move
outwardly. Thus even if the piston is inclined to
stick, once the member 81 is unscrewed, the piston
29 will be in its outward venting position.
In the event of both the valve member 26 and
the piston 29 becoming stuck there is still the
safety valve member 13 in the top of the vessel 1
to stop excess pressure developing. Still another
safety arrangement (not shown) may be provided by
deliberately weakening a portion of the vessel 1
so that this portion of the vessel bursts in a
controlled manner when the pressure exceeds a
predetermined level, alternatively the vessel body
4 may be formed such that upon excess pressure
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developing, it distorts destroying the seal between
the vessel body 4 and the lid 5.
Referring again to Figure 1, the paint pad
8 is in some respects similar to a conventional pad
in that it has an outer layer of material 46 supported
on a foam backing layer 47 which has a closed cell
structure so that it does not absorb the paint' the
foam backing layer is in turn attached to a metal
backing plate 48. Unlike conventional paint pads,
however, the metal backing plate has a central
aperture at which the flexible tube 7 terminates
and the foam backing layer 47 contains a series of
passages extending outwardly from the central aperture
and terminating within the layer 46 at a plurality
of locations distributed over the pad.
The flexible tube 7 passes through the handle
49 of the paint pad 8 and an on/off switch or valve
50 and a regulating screw 51 are provided on the
handle 49.
The on/off switch 50 is shown in Figure 4
and comprises a switch member 52 pivotally mounted
intermediate its ends on the handle 49. One end of
the switch mernber 52 presses via a small plate 53
on the tube 7 and the other end is used to operate
2S the switch. In the position shown in Figure 4 the
switch is in the "off" position and the tube 7 is
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squeezed flat. If a user now pivots the switch
member 52 anticlocXwise (as seen in Figure 4),
the member 52 passes through a dead centre position
and then allows the tube 7 to return through its own
resilience to a circular cross~section, The plate
53 reduces the frictional force opposing movement
of the tube 7 and reduces wear on the tube.
The rate of flow of paint through the tube 7
can be controlled by the regulating screw 51.
Screwing in the screw 51 restricts the internal
cross-sectional area of the tube 7 by flattening the
tube. In the innermost position of the screw 51 the
tube may be completely closed.
The operation of the apparatus shown in
Figures 1 to 4 will now be described.
Paint is supplied to a user in the container
2 with the plug 80 sealing over the diaphragm 14.
The user removes the plug 80 and places the container
2 in the vessel 1 and screws the lid 5 onto the vessel
1 at the same time inserting the pipe 3 which is
secured to the lid 5 into the central aperture in
the diaphragm 14. The user then ensures that the
switch 50 on the paint pad is in the "off" position
and inserts a capsule 24 into the assembly 9 as
already described. The vessel 1 may be carried in
the hand by the handle 10 but preferably the handle
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10 is suspended from a belt passed around the waist
of the user since this is less tiring and also leaves
the user with a free hand. The handle 10 may be
provided with a clip (not shown) for attaching the
vessel 1 to a belt. The vessel 1 is pressurized
by screwing in the cap assembly 31.
The user adjusts the rate of flow of paint
with the regulating screw or regulator 51 and is
then able to paint without interruption. The
switch 50 enables the user to start and stop painting
at will.
In the particular example described the
container 2 has a capacity of one litre which is
sufficient to, paint about t,welve square metres of
a surface and the capsule holds four litres of gas
(at atmospheric pressure). The pressurè in the
vessel 1 is normally regulated to be in the range
of between ten and twenty pounds per square inch
above atmosphere while the pressure in the capsule
is of the order of 700 to 900 pounds per square
inch. One capsule contains more than sufficient
gas to discharge all the paint from a container.
In order to recharge the vessel 1 with a
new paint container the cap assembly 31 is unscrewed
to the limit of its movement, this causes the valve
member 26 to close (if it is not already closed) and
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compressed gas in the vessel 1 moves the piston 29
outwards and escapes to atmosphere around the edge
of the piston. Even if the piston 29 tends to
stick it is positively pulled outwards by engagement
o~ the head 84 with the adjusting member 82. The
lid 5 can then be unscrewed, since the vessel 1 must
be at ambient pressure, the pipe 3 withdrawn from
the container 2, the container removed from the
vessel 1, and a new container inserted as described
above. As the pipe 3 is withdrawn through the
diaphragm 14, paint on the outside of the pipe is
wiped off the pipe.
It is helpful for the user to have some
indication that the vessel 1 is pressurized and for
this purpose a pressure indicator as shown in
Figure 7 may be provided. The indicator is mounted
on the vessel lid 5 which is formed with an inwardly
extending circular rib 152 over which a flexible
diaphragm 153 is fitted. The upper face of the
diaphragm 153 carries a projection 154 which is
accommodated in a hole in the lid 5. When the
vessel is not pressurized the diaphragm 153 is
not flexed and the top of the projection 154 is
below the upper surface of the lid 5. Upon
pressurisation of the vessel, however, the diaphragm
154 protrudes from the lid 5, the projection 154 is
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- 21c -
preferably in a colour contrasting with the lid 5
so that it can be easily seen.
After use the apparatus is cleaned. Only the
pipe 3, tube 7 and paint pad 8, however, require to
be cleaned since the other parts of the apparatus do
not come into contact with the paint. Even if the
vessel 1 is inadvertently knocked over during use,
the diaphragm 14 retains the paint in the container
2 so that the vessel 1 does not need cleaning.
~ince both the switch 50 and regulator 51 act
externally on the tube 7 they do not become contaminated
with paint. The paint pad 8 is dismantleable to
facilitate cleaning.
The 'O' ring seals ~re made of a material
which is not affected by the fluid to which they are
exposed in use.
Conveniently the vessel 1, the flexible tube
7, the assembly 9, the handle 10, and the paint
pad 8 are made of plastics materials. For water
based paint the container 2 is preferably made of a
plastics material but, since plastics materials
are attacked by solvent based paints (for e~ample
gloss paints) over an extended period of time, the
container 2 is preferably made of metal if it is
to contain solvent based paints. The container 2
may be made in various other forms. For example the
1 155802
- 21d -
container may be made of cardboard with a metal
foil liner.
It may be desirable to provide means to
prevent the insertion in the vessel of an unsuitable
container, that is one containing a paint of inferior
grade or a grade different to the paint which the
apparatus is primarily intended to feed. Such
means may, for example, take the form of one or more
interengaging ribs and grooves or other formations
on the external surface of the container and the
inner surface of the vessel, or of suitably shaping
1 ~55~02
-22-
the interior contour of the vessel to inhibit the insertion therein of a
container which has other than a matching shape.
If desired a multiplicity of ~alls may be provided on the surface
of the paint 16, the balls each being of a diameter slightly bigger than
the internal diameter of the pipe 3 and having a density very slightly lower
than that of the paint so that they float with nearly all of the ball below
the paint surface. A sufficient number of balls are provided such that
there are two layers of balls across the entire surface of the paint. As
the level of paint in the container 2 drops to a low level the lower layer
of balls approach the bottom of the pipe 3; finally when the paint level is
almost down to the level of the bottom of the pipe 3 the lower layer of
balls reach the level of the bottom of the pipe 3 and one of the balls
becomes located over the end of the pipe 3 preventing further flow of liquid.
This automatic interruption of the paint flow when the container 2 is
almost empty ensures that gas does not enter the pipe 3; if gas were allowed
to enter the pipe 3 this could result in sputtering of the paint from the
pad 8.
In the drawings the pressure vessel 1 is shown with square corners
and straight sides. In accordance with well kn~wn design procedure for such
vessels, however, the corners are preferably rounded off and the sides bowed
outwardly.
After use of apparatus described above, the apparatus may be cleaned
by pumping a solvent, which in the case of water based paints may be water,
through the apparatus using the pressure of the capsule of carbon dioxide.
In the illustrated apparatus a paint pad is attached to the free end
of the tube 7. Ilowever, a paint brush or roller may alternatively be attached,
these devices having an on/off switch and a regulator similar to the paint
pad. When using a brush, the flow of paint may be required to be somewhat
1 1~5~02
- 23 -
slower and this can be achieved by appropriate adjustment of the regulator
on the brush handle. If desired the applicator may be of a modular
construction consisting of a handle incorporating the on/off switch and
the regulator and a plurality of heads including at least one pad, roller
and brush which can be attached to the handle. The on/off switch and the
regulator may be combined into a single control if desired. For the sake
of simplicity the regulator may be omitteu.
A shoulder strap may be attached to the vessel 1 to allow a user to
carry the vessel over his shoulder or any other arrangement may ~e provided
to enable a user to carry the vessel.
The lid 5 may be clamped onto the body 4 of the vessel 1 by a
plurality of toggle clamps, instead of screwing the lid onto the body.
This has the advantage that the '0' ring or diaphragm is not subjected to
a rubbing action upon tightening of the lid 5. Furthermore the toggle
clamps can be spring biased into their closed position in such a way that
if the pressure in the vessel exceeds a predetermined level at least one of
the toggle clamps is forced open and the lid 5 lifts off the vessel body 4.
A particular example of a lifting lid assembly is shown in Figure 5.
In this figure, the vessel body 104 is shown with a lifting lid 105, an 'iO'
ring seal 106 being provided between portions of the walls 104 and 105
which with the vessel 1 unpressurized are overlapping. The lid 105 is
retained on the body 104 by a ring clamp 107 screwed onto the body 104
and a number of springs 108 are provided around the periphery of the lid 105
between the lid 105 and the ring clamp 107. In the position shown in
l~igure 5, the vessel is unpressured, the lid 105 rests on top of the body
104 and the springs 108 are substantially unstressed.
As the vessel 1 is pressurized the lid 105 lifts off the body 104
1 155802
- 24 -
and the spTings 108 become stressed. Under normal operating pressure portions
of the walls lQ4 and lQ5 continue to overlap and the '0' ring 106 seals the
interface there between. Upon excess pressure developing, however, the
springs 108 are further compressed and the lid 105 is lifted clear of the
'0' ring 106 venting the vessel.
In the arrangement shown in Figure 2 the diaphragm 14 has a hole 15
which ensures equalisation of pressure between the opposite sides of the
diaphragm. In place of the aperture, a slit may be provided in the diaphragm,
extending for example radially from the central aperture in the diaphragm.
Alternatively it may be possible to omit both the pin hole and the
slit and rely on the diaphragm flexing in the region of its central aperture
to allow the passage of gas between the diaphragm 14 and the pipe 3.
The diaphragm 14 may, if desired, initially be without the central
aperture. In this case the pipe 3 is provided with a pointed end and is
sufficiently stiff to puncture the diaphragm when it is first pressed
through the diaphragm. It may be advantageous to neck
1 155802
- 25 -
the pipe where it en~age the diaphragm. This may
be advantageous if an anti-sputter arrangement of
a kind which will now be described is employed in
the apparatus shown in Figure 2. The anti-sputter
arrangement consists of providing a compression
spring under the container 2 so that as the container
2 empties of paint it becomes lighter and is lifted
up relative to the vessel 1, and, when the container
2 is virtually empty of paint, the end of the pipe
3 bears against the bottom of the container 2 sealing
over the pipe 3. If desired a resilient member for
example a closed cell foam may be provided on the
bottom of the container 2 under the pipe 3 to
ensure that a good seal is obtained between the
pipe and the container,
Necking the pipe 3 where it passes through
the diaphragm ensures that there is very little
resistance to relative motion of the container 2
and the pipe 3 and also allows free flow of gas
into the container. When the pipe 3 is withdrawn
from the container 2 after use the lower unnecked
portion of the pipe is wiped clean as it passes
through the diaphragm.
In the pressure reducing valve assembly shown
in Figure 3 a piston 29 is used. As an alternative
a diaphragm connected to the wall of the bore 30 and
1 15S802
- 26 -
spring biased in the same manner as the piston 29
could be used. In this case it may not be possible
for gas pressure to be vented through the cap 31.
An alternative way of venting the gas may be to open
the safety valve. The spring 34 which biases the
valve member 26 into its closed position may be
omitted since gas pressure from the capsule 24 can
be used to perform this biasing function.
The housing 20 of the pressure reducing valrve
assembly 9 may be provided with external radially
pro]ecting fins to facilitate screwing and un-
screwing of the housing 20. Also the capsule 24
may be located in the housing 20 in such a way that
when the housing is unscrewed the capsule 24 is
automatically withdrawn from the piercer 42 and
comes away with the housing from which it is then
removed.
The safety valve assembly may be modified
in such a way that every time the lid 5 is secured
to the vessel body 4 the safety valve is tested.
An arrangement of this kind is shown in Figure 6.
In this arrangement the safety valve assembly
consists of a housing 110 in which a valve member
111 carrying a closure member 112 is mounted. A
25 spring 113 biases the closure member 112 onto a
spherical seat formed at the bottom of the housing
110. Upon excess pressure developing the closure
1 155802
- 27 -
member 112 is lifted off its seat venting the vessel.
The interface of the vessel body 114 and screw-on
lid 115 is around the outside of the body and is
sealed by an 'O' ring. On one portion of the top
of the vessel body 114 a ramp shaped cam surface 116
is provided. A lever 117 is pivotally mounted on
the lid 115 at one end and has a cam follower 118 on
the other engaging the top of the vessel body 114.
Intermediate the ends of the lever 117, the lever
touches or is spaced just underneath the lower end
of the valve member 111. As the lid 115 is screwed
onto the body 114, the lever 117 enga,ges the cam
surface 116 once in each revolution of the lid and
this engagement raises the lever 117 lifting the
valve member 111 into its vented position. When
the lid is fully screwed on, the cam surface 116
is arranged to be spaced circumferentially from the
cam follower 118 so that the safety valve assembly
is closed.
Although the apparatus has been described
with reference to the application of paint, it can
be used to apply other liquids to a surface. For
example it can be used to apply preservative to a
wooden surface or for washing surfaces. The apparatus
can also be used to feed liquids to other kinds of
applicators, for example to a spray head. With a
1155802
- 27a -
spray head, the apparatus can be used as a garden
spray apparatus.
