Improvements in Appliances for Spraying Oil Paint, Varnish, and other Viscous Matters upon Surfaces
Year: 1896

page_text: Date of Application, 10th Feb., 1896
Complete Specification Left, 10th Nov., 1896-Accepted, Eth Feb., 1897
PROVISIONAL SPECIFICATION.
Improvements in Appliances for Spraying Oil Paint, Varnish, and
other Viscous Matters upon Surfaces.
We, THE PNEUMATIC PAINTING MACHINE (1895) CORPORATION LIMITED
of 86, Charing Cross Road, in the County of Middlesex, Manufacturers, and
HOWARD CRUNDEN CLEAVER of 3, Eden Street, Hampstead Road, in the
County of Middlesex, Furniture Manufacturer, do hereby declare the nature of
this invention to be as follows:-
This invention relates to improvements in appliances such as described in
previous Letters Patent dated the 20th day of May 1893, No. 10117; for spraying
oil paint, varnish, and other viscous matters upon surfaces to be painted, varnished,
or otherwise coated. Owing to the viscous and adhesive character of the material
to be sprayed it is liable to clog the spraying nozzle and can only with difficulty
be so finely and uniformly atomized as is necessary in order to deposit it uniformly,
smoothly, and lightly upon the surface to be coated. Besides improving the
atomizing action of the blast of air and the avo ding the clogging of the nozzle
the present improvements have for object to enable the action to be brought more
completely under control and to be more easily regulated to avoid waste of air and
to render the air blast available for blowing dust off the surface upon which the
paint, varnish, or other viscous matter is to be sprayed.
With a view to attain these advantages the improved atomizer is so constructed
that the air blast is delivered through a convergent nozzle by which it is directed
in a concentrated jet upon an impact surface perpendicular to the direction of the
air jet, said surface coinciding with the point at which the paint issues so that the
immediate effect of the blast is to flatten the stream of paint upon the impact
surface preparatory to causing it to spread out in the form of a thin film upon
divergingly inclined surfaces adjacent to the impact surface and leading to the exit
or spraying orifice of the atomizer.
The atomizer may consist of a body portion adapted to be connected to the blast
and pipes in such manner as to be readily detachable for cleaning, the paint pipe
communicating with a channel leading to the impact surface where the air jet
impinges on the stream of paint. For convenience of cleaning, this channel is an
open groove covered by a plate detachably secured by a wing nut and screw.
The exit or spraying orifice may be a slit of A, M, semicircular, or other similar
form or of two such formis juxtaposed base to base so that the divergent paint-
spreading surfaces which lead to the orifice form the sides of a cone, pyramid, or a
segment of a cone, pyramid, or other figure (according to the form of the orifice)
having the flattened impact surface at the truncated apex. But whatever may be
the form of the orifice the one boundary of the slit should be an acute arris
(formed by the intersection of the inclined surfaces above referred to with the face
of the atomizer) from which the atomized particles may be readily blown off, and
in order to erable the width of the slit to be varied it is necessary that the one
boundary should be adjustable with regard to the other. This may be conveniently
done by formning the inclined surfaces above referred to on the end of a tongue
having parallel sides and a A, M., or otherwise shaped end, said tongue
being part of the cover plate above referred to and fitting in a correspondingly

page_text: shaped recess in the body portion with which the cover plate is flush. The narrow
slit or spraying orifice left or formed between the end of the tongue and the recess
is varied in width by making the cover plate adjustable so as to cause the tongue
to enter the recess more or less and so regulate the area of the slit. The end of
the tongue is bevelled on the inner side to form the paint spreading surfaces above
referred to. The paint channel terminates just before reaching these bevelled
surfaces so as to expose the impact surface formed by the back of the tongue
which surface is directly opposite and perpendicular to the axis of the air blast
cone so that the air jet impinges directly on the exposed stream of paint which is
at once flattened against the impact surface and spread out in the form of a thin
film on the bevelled surfaces of the tongue until it reaches the acute arris from
which it is blown off by the concentrated action of the blast in a finely atomized
form. Means are provided to check the spreading of the paint except in the
direction of the inclined surfaces and with this object the paint channel euters the
spraying orifice in a direction substantially normal to the direction of the air jet
issuing from the cone and opens therein through a surface which is so inclined that
the back of the stream of paint is first exposed to the jet.
The paint and blast pipes are respectively controlled by stop cocks to regulate
the blast and the flow of paint or other material to be sprayed the two cocks being
coupled so that they will be turned simultaneously, although they are not both
opened at the same moment the thoroughfare of the blast cock being so formed as
to open and give passage to the blast by a very small angular motion before the
paint cock has been turned sufficiently to give passage to the paint. A preliminary
blast of air is thus obtained in advance of the paint which besides being useful to
blow the dust off the work is necessary to ensure the thorough atomization of the
particles of paint first delivered to the atomizer nozzle, since, were the paint to
reach the atomizing point in advance of the air there would be danger of spoiling
the work by depositing clots of imperfectly atomized paint.
A. M. & WM. CLARK,
53, Chancery Lane, London, Chartered Patent Agents.
Improvements in Appliances for Spraying Oil Paint, Varnish, and
other Viscous Matters upon Surfaces.
We, THE PNEUMATIC PAINTING MACHINE (1895) CORPORATION, LIMITED,
of 86, Charing Cross Road, in the County of Middlesex, Manufacturers, and
HOWARD CRUNDEN CLEAVER of 3, Eden Street, Hampstead Road, in the
County of Middlesex, Furniture Manufacturer, do hereby declare the nature of
this invention and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement:-
This invention relates to improvements in appliances such as described in
previous Letters Patent dated the 20th day of May 1893 No. 10,117 for spraying
oil paint, varnish, and the like upon surfaces to be painted and varnished.
The defects which the present improvements are desigued to obviate arise
principally from the fact that owing to the viscous and adhesive character of the
material it is liable to clog the spraying nozzle and can only with difficulty be so
finely and uniformly atomized as is necessary to produce a uniform, smooth, and
light coating upon the surface to be painted or varuished. Besides improving the
atomizing action of the blast of air and the avoidance of the clogging of the
nozzle with paint or varnish, the present improvements have for object to euable

page_text: the action to be brought more completely under control and to be more easily
regulated and also to render the air blast available for blowing dust off the surface
to be painted or varnished immediately before the paint or varnish is atomized and
sprayed thereon.
The improvements are illustrated in the accompanying drawings forming part
of this specification wherein
Figure 1 is an elevation (partly sectional) of the whole apparatus.
Figure 2 is an enlarged longitudinal section of the ejection end of the nozzle.
Figure 3 is an end view of the nozzle, Figure 4 being a similar view with the
adjustable cover plate removed.
Figure 5 shews, to a still further enlarged scale, a rear view of the atomizer.
A is the closed paint container supplied through pipe B and tap a with air under
pressure from an air pump or compressor. B₁ is the flexible continuation of the
air supply pipe connected to the blast pipe of the atomizing nozzle and C is
the paint delivery pipe leading from the bottom of vessel A to the paint pipe c-
of the atomizing nozzle, a chamber D containing a strainer d being interposed in.
the pipe call as described in the specification of the previous patent aforesaid.
The pipes bc are respectively controlled by stop cocks ef to regulate the blast
and the flow of paint, the lever arms ef by which the two cocks are moved
being coupled by a link g so that they will be turned simultaneously. Or instead
of two separate cocks coupled, a single plug having ports corresponding to the
paint and air pipes, and received in a socket to which both said pipes are
connected, may be used. But in either case the thoroughfares are not both opened
at the same moment, the thoroughfare through the plug of the cock e being so.
much larger than that through the cock that it opens to give passage to the
blast by a very small angular motion of its operating lever before the cock f
bas been turned sufficiently to give passage to the paint. A preliminary blast
of air is thus obtained in advance of the paint which, besides being useful to.
blow the dust off the work, is absolutely necessary to ensure the thorough.
atomization of the particles of paint first delivered to the atomizer nozzle since,
were the paint to reach the atomizing point before the air, there would be danger
of spoiling the work by clots of imperfectly atomized paint. The air blast is.
delivered through a conical nozzle by which it is directed in a concentrated
jet upon the point at which the paint issues as hereafter described so that the
immediate effect of the whole volume of the blast is to cause the paint to become.
spread in the form of a thin film upon the divergent surface of the atomizer.
The atomizer consists of a body portion i having sockets at back that fit on the
ends of the pipes be to which the atomizer is attached by the screw stud j
and wing nut ke so as to be readily detachable for cleaning. The bore of the paint
pipe c communicates, through an orifice, with a channel made in the recessed
face of the body portion and leading to the point where the air jet impinges
on the stream of paint and blows it out into a thin film on the divergent paint-
spreading surface of the atomizing nozzle. For convenience of cleaning, this
channel is made in the form of an open groove in the recessed face and is
covered over by a plate m making a paint-tight joint with the face i', the plate m
being held in position by the wing nut k and screw j.
In the form of atomizing nozzle shewn in Figures 2 to 5 the plate m is in one
with a tongue n having parallel sides and a A shaped end, said tongue fitting in a
correspondingly shaped recess in the upper part of the body, with which part
the plate m is Hush. Between the end of the tongue and recess a narrow shaped
slit o is left which is the spraying orifice and the cover plate m is sufficiently
adjustable to cause the tongue to enter the recess more or less and so regulate the
area of the slit o. The A shaped end of the tongue n is bevelled on the inner side
as shewn at n so that the spraying orifice is gradually contracted down to the form
of a narrow slit o. The paint channel terminates just before reaching the bevelled
surfaces n¹ so as to expose an impact surface n² formed by the back of the tongue n
which surface is directly opposite and perpendicular to the blast issuing from the

page_text: cone h so that the air jet issuing from the cone impinges directly on the exposed
stream of paint which is at once flattened against the impact surface n² and spread
out in the form of a thin film on the bevelled surfaces n' of the tongue until it
reaches the acute edge thereof which forms the one boundary of the slit o from
which edge it is blown off by the concentrated action of the blast in a finely
atomized form. The spreading of the paint in the lateral direction from the
point where it is first acted on by the blast is checked by the sides of the
channel being continued beyond the point where the air jet strikes the stream of
paint so that the latter is confined laterally and directed towards the apex of the
tongue. With this object the channel leads in a direction substantially normal
to the direction of the air jet issuing from the cone and opens through a surface s
inclined to that direction so that the back of the stream of paint is first exposed to
the jet.
; or it
It will be evident that the slit o need not necessarily be A shaped. It might
with almost equal efficiency be made of semi-circular form thus
might be of double (or even multiple) A shape thus M; moreover the A shaped
slit might be otherwise duplicated, the two slits being placed base to base thus: (BB
;
in which case the bevelled surfaces n¹ n' of the two slits would form the sides of a
truncated pyramid upon which the paint would be caused to flow and from the
base edge of which it would be sprayed off. Similarly two semi-circular slits
might be placed base to base thus ; the bevelled rear surfaces n' n' then
forming a truncated cone, the film of paint spreading upon said surfaces and being
sprayed off from the base edge by the surrounding annular blast of compressed air.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed we declare that what we
claim is
1. An atomizer for spraying oil paint or varnish, formed by the combination of
an air jet nozzle or cone, an impact surface directly opposite thereto, a paint
supply channel leading as described to the impact surface, divergent paint-spreading
bevelled surfaces leading from the impact surface and terminating in acute edges
forming the one boundary of a narrow slit the other boundary of which is formed
by the enclosing walls of the atomizer substantially as described.
2. An atomizer for spraying oil paint or varnish, formed of an air jet nozzle,
an impact surface directly opposite thereto, a paint supply channel leading as
described to the impact surface, bevelled surfaces leading from the impact surface
and terminating in acute edges forming the A shaped end of a tongue or plate
fitted adjustably within the body part of the atomizer so as to leave between said
acute edges and the opposite walls of the body part a narrow A shaped slit whose
width is variable by shifting the tongue as described.
3. The combination, with the herein described atomizer and with the paint and
air supply pipes, of a double-ported stop-cock or of stop cocks coupled so as to be
moved together, the one for regulating the air supply being adapted to open before
the other so as to enable a preliminary blast of air alone to be directed upon the
work for removing dust and ensure the atomizing of the paint from the outset of
the operation as specified.
Din 10th
C ATL 1000
A. M. & WM. CLARK,
53, Chancery Lane, London, Chartered Patent Agents.