IMPROVEMENTS IN STRAINERS OR PERFORATED PROAL
Year: 1883

page_text: LETTERS PATENT to William Lawrence of St Mary Axe in the County of
Middlesex for an Invention of IMPROVEMENTS IN STRAINERS OR PERFORATED
PROVISIONAL SPECIFICATION left by the said William Lawrence at the
Office of the Commissioners of Patents on the 6th September 1883.
WILLIAM LAWRENCE of St Mary Axe in the County of Middlesex,
MENTS IN STRAINERS OR PERFORATED SURFACES,"
"IMPROVE-
The improvements consist in perforating metal surfaces either flat circular or
conoidal or otherwise as follows:
One means of perforation being to take a plate of metal and place it on a
suitable tool such as the face plate of a large lathe and then turn or cut in it
concentric or convoluted grooves. The grooves or rings being cut in a certain
depth. The plate is then reversed on the face plate in such a manner that rings or
grooves are cut in which will cross the rings or grooves on the back of the plate.
The plate will thus become perforated where these grooves intersect each other.
By this system of perforating, plates or surfaces may be perforated with great
accuracy and very fine perforations may be made. The perforations may be rolled
or partly rolled in by passing plates of metal between ribbed rollers so made that
the ribs on the one intersect those of the other. Metal plates or rolled or cast
metal plates may be finished up with cutting or grinding tools when necessary to
finish or modify the perforations. Or metal plates may be rolled or cast with ribs
only on one side, the plain side may then be cut with grooves and so as to intersect
the grooves or channels rolled or cast in. Or such plates may be formed into pipes
or split cylinders and placed on a mandril suitable for the purpose and have grooves
so turned in it that they may cross or intersect the grooves cast or rolled on the
other or reverse side of the plate; or cylinders may be cast or rolled and turned or
grooved inside and out and the grooves inside and out may either be made to
intersect each other and made as in a right and left handed screw the one channelled
right handed and the other left handed, or they may run parallel with each other
or fit into each other and such tubes or surfaces may be used either in the tubulous
form, or the split tubes may be opened out into the flat form. Or only one side

page_text: may be grooved in this circular form and then when the plate is opened out it may
be placed on the face plate of a large lathe and have concentric rings turned or
chased in it on the reverse side. Such plates may be used in paper making and
forming designs or water marks, and any kind of design may be built up or inlaid
and for a great variety of purposes.
The metal surfaces may be formed into any desired shape and domes or conoidal
shaped strainers may be made and have the grooves turned in them. In cases
where the grooves or channels run parallel with each other the perforations on the
plate are then made either by sawing or cutting fine grooves in any way or at any
angle across the direction of the channels on one or on both sides of the plates, or
the perforations may be made laterally between or on either side of the channels,
also the channels may be of irregular shape and depth. Also in the place of grooves
cut in they may be cast in, or corrugated metal plates may be used and grooves
formed therein, and such corrugated plate may be perforated either before or after
corrugating. Perforated plates with the perforations made laterally will also be
very serviceable for kilns such as for drying malt and hops, the perforations being
lateral will prevent the dust or finer parts from falling through the plates, the
channels in such plates will require to be made larger and deeper than for ordinary
purposes. Perforated plates also having the grooves on the upper and underside
running parallel may also be either cast or built up in which case the channels
would sometimes be intersected by the cross bars which would be required to hold
the whole together and by the ribs of the frames when cast in frames, or panels or
panelled plates. The invention embraces forming any of the above metal surfaces
that may be desirable, into a cylindrical or disc shaped, or other form, suitable for
revolving on a shaft or in any other manner, or for any rocking cradling or other
arrangement. Also said perforated surfaces may be arranged in conjunction with
brushes or air pumps or other arrangements for the purposes of working and
cleansing them.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said William Lawrence in the Patent Office on the 6th March 1884.
WILLIAM LAWRENCE, of St Mary Axe, in the County of Middlesex "IMPROVE-
MENTS IN STRAINERS OR PERFORATED SURFACES
"
My invention chiefly relates to Strainers in which the perforations or
apertures are formed by the intersection of two sets of grooves which cross
each other in parallel planes.
According to my present invention such apertures are produced in a plate of
metal or other suitable material by cutting, rolling, pressing, or stamping
grooves on opposite sides of the said plates.
In the usual way cut Channels, either curved or straight, so that the channels
on the upper and lower side of the plates cross or intersect each other. But for
some purposes I find it preferable to make the upper and lower row parallel with
each other, the perforations being in such case lateral and produced as hereinafter
described This kind of perforations is useful for cylindrical forms, or where a
revolving action and a speedy cleaning of the straining surface is a desideratum.
My Invention also relates to the preparation of thick metal or other plates
previous to the formation of the apertures,
One method of preparing the plate is to roll it so as to form grooves or panels
which may afterwards be finished by cutting, the grooves being either made
continuous or so as to form broken lines. Or I cast grooves or ribs on one side of
the plate or surface so as to reduce the cutting process to one side of the plate.
Also when making the plate of steel I propose to temper them in order to
increase their hardness and durability.
Figure 1 is a plan of a perforated plate having the Grooves on the upper side
curved while those on the underside are straight. Figure 2 is a perspective view
of a plate having the grooves upon the upper side smaller than on the under side-
Figure 3 is a perspective view of a plate having rectangular grooves or channels
formed on the upper and under side-Figure 4 shows grooves formed by flat bars
on the upper side of the plate and narrow triangular bars on the underside thereby
producing slots at the intersection of the upper and lower grooves-In Figures 2, 3
and 4 the upper bars are marked a, the lower bars b and the perforations c
Figure 5 shows a plate with the perforations divided into panels leaving ribs in
the plate which are not touched by the cutting tool. The panels on the upper side
are immediately opposite to those on the underside of the plate, but the grooves
are in an opposite direction-Figure 6 shows a section of a plate provided with
panels previous to the cutting process in which the panels are formed in the
underside of the plate only. Perforated plates, as shewn at Figure 1, are intended
to be used for general straining purposes and for a small thickness of inetal.
This
kind of plate may be fitted into skeleton frames of any desired patterns or designs.
For fineness of perforations this form is particularly applicable, as the grooves may
be curved in section, as shown enlarged in Figure 7, where the extreme thinness of
the groove at the bottom gives a very fine perforation without sacrificing strength.
Thin plates having this kind of perforation may be used for many purposes
instead of wire cloth or woven material-But when it is desirable to make strong
straining plates, such as false bottoms for mash tuns in Breweries, then this
system of making the panels in the plate itself is preferable to using skeleton
panels. The panels, as before described, may be made either by previously rolling
or casting them on the plate, as in Figures 6 and 8, or they may be formed as in
Figure 5 where the grooves are not continuous, and the spaces between the
perforated or grooved parts of the surface form the bars or ribs. The panels (that
is the space between the ribs or inside the rectangles) may form any of the
grooved straining surfaces of the type described, for instance the surfaces shown in

page_text: Figures 2. 3. 4.7 and described above. Figure 9 shows an example of a perforated
plate, where the channels upon the upper and under sides of the plate run parallel
with each other, the perforations in this case being lateral-The channels may be
cast in and then finished upon a planing or cutting machine If the plates are
cast with transverse ribs on the back, then the perforations can he easily cut into
the side of the grooves, but if it is desired to plane the underside as well as the
top, then the transverse strengthening bars should form separate pieces to be fixed.
on the underside after planing and before cutting the lateral grooves. It is
obvious, that the grooves, if continuous, would cut through the metal and so sever
the plates into strips. If, however, the lateral grooves are not cut continuously
and only as slots, then the intermediate spaces are sufficient to hold the whole
together, as in Figure 9, so as to render the transverse bars unnecessary. The
channels on the top side of the plate are marked a, those on the underside b, the
transverse bars c, the slots or perforations d. In Figure 11 a modification is
shewn of a plate the apertures of which are lateral, but not produced by cutting-
In a cast plate such perforations may be made direct in the casting and if
necessary only cleaned out after trimming up the casting. The same will hold
good with Figure 10, in which case the openings are still lateral, but the bars or
the plates generally are in a slanting position: These and other forms of
perforated or slotted surfaces, however as before stated, may be used with
advantage in the cylindrical form where it is desirable to apply rotary motion, the
straining surface being mounted on an axle adapted to turn in bearings. Figures
12 and 13 shew a cylinder adapted to revolve on a shaft. a a shews the
cylindrical straining surface or cylinder-b shows the transverse strengthening
bars, cc the perforations; d shows the shaft and f the arms securing the transverse
bars to the shaft-A portion of the cylinder is supposed to be broken away in
Figure 12 at g to show the construction. This diagram is only intended to show the
method of using the straining surface to construct the cylindrical form of strainer
and is not intended to show the cylinder completed or the washing or cleaning
arrangements, as the latter are not in themselves forming a part of my invention.
This diagram will also serve for other perforated surfaces, such for instance as
shown in Figures 9. 10 and other figures. As before stated, my invention
comprises a system of making straining surfaces in the cylindrical form. I take
a cylinder of metal or a split tube and cut grooves or chases in it, either in rings
or at any convenient angle, the chases on the inner side being made at an angle to
those on the outer, so that the Cylinder may be perforated at the lines of
intersection of the inner and outer_grooves. I may use such perforated surfaces
either in the cylindrical form, or I can open out the cylinder after cutting it
through or parting it, and thus form a flat or otherwise shaped plate, or I may cut
grooves on the outer side of the cylinder only, and then, after opening it out into a
plane, place the plate upon the face plate of a lathe and cut concentric rings, such
as the rings indicated in Figure 1. It is not necessary to describe or show a
diagram of suitable rollers for preparing the plates in the rough, as plates of iron
are already rolled with styles and panels to give a roughened surface for instance,
plates for iron pavements.
I will observe, in conclusion, that I do not claim the improved types of strainers
as far as they are already covered by my letters patent N° 1205 of the year 1883,
but all other forms, modifications or applications of the same.
In witness whereof I, the said William Lawrence have hereunto set my hand