DISTRIBUTEUR A TIROIRS

VALVE

Abrégé anglais

ABSTRACT OF THE DISCLOSURE
A valve for fluid conduits, said valve
including two cylinders arranged parallel to each
other with their circumferential surfaces in
contact, each of said cylinders having a
circumferentially extending semi-circular groove
formed in the surface thereof the depth of which
varies along its length, said grooves defining
an aperture through which, in use, fluid is
constrained to pass, whereby upon rotation of
said cylinders relative to each other the size
of said aperture varies to vary the rate of flow
of fluid through said valve. The cylinders
are rotated in unison in opposite directions by
a pair of identical intermeshing pinion gears,
one of which is caused to rotate by means of a
rack.

Revendications

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A valve for fluid conduits, said
valve including two cylinders arranged
parallel to each other with their circumferential
surfaces in contact, at least one of said
cylinders having a circumferentially extending
groove formed in the surface thereof the depth
of which varies along its length, said
cylinders at the, or each, groove defining
an aperture through which, in use, fluid is
constrained to pass, whereby upon rotation of
said cylinders relative to each other the size
of said aperture varies to vary the rate of flow
of fluid through said valve.
2. A valve as claimed in claim 1, wherein
opposed grooves are provided in the surfaces
of said cylinders to define said aperture.
3. A valve as claimed in claim 1 or 2,
wherein the, or each, groove is of semi-circular
cross-section.
4. A valve as claimed in Claim 1, wherein
means are provided to rotate said cylinders in
unison and in opposite directions.
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5. A valve as claimed in claim 4,
wherein said cylinders have extended support
shafts formed integrally therewith, or
attached thereto, and said means for
rotating said cylinders in unison and in
opposite directions are a pair of identical
pinion gears carried by the respective shaft
extensions and meshing with each other.
6. A valve as claimed in claim 5,
wherein said pinion gears are rotated by
means of a rack meshing with one of said
pinion gears and linearly movable to rotate
said pinion gears and therefore said
cylinders.
7. A valve as claimed in claim 6,
wherein said rack is moved by a fluid operated
ram.
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Description

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This invention relates to an improved
valve which has been developed primarily for use
in association with flexible pipes or conduits
to control the rate of fluid flow therethrough.
The invention is also suitable for general
application in association with rigid conduits
where fine control of the rate of flow is re~uired
and especially in situations where the fluid
flowing through the conduit contains highly
abrasive materials.
There are in existence many types of
control valves for flexible pipes, most of them
being rubber sleeve valves or pinch valves which
work on the principle of squeezing a flexible
rubber sleeve to restrict flow. This causes
the circular orifice to become distorted and
extreme wear occurs at the pinched area due to
rubber in tension at the fluid surface. Flow
control is difficult due to non-linearity of
the closure. Generally, the size of the valve
is large for the passing capacity.
The present invention envisages a valve
for fluid conduits, said valve including two
cylinders arranged parallel to each~other
with their circumferential surfaces in
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contact, at least one of said cylinders
having a circumferentially extending groove
formed in the surface thereof the depth of which
varies along its length, said cylinders at the,
S or each, groove defining an aperture through
which, in use, fluid is constrained to pass,
whereby upon rotation of said cylinders
relative to each other the size of said aperture
varies to vary the rate of flow of fluid through
said valve.
In order that the invention may be more
readily understood it will now be described by
way of example with reference to the accompanying
drawings in which:-
Figure 1 is a dlagrammatic perspective
view of the main elements of a valve according
to the invention,
Figure 2 is an external view of a valve
according to the invention,
Figure 3 is a cross-sectional view on
~: line B-B of Figure 2, and
Figure 4 is a cross-sectional view on
: line A-A of Figure 2.
The valve has a casing 10 made from a
suitable metal which may be aluminium. Within
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the casing there is a valve chamber 12 having
a lining 13 made from a corrosion and abrasion
resistant material such as polyurethane. The
upper and lower covers 14 and 16 of the casing
are provided with recesses 18 having bearings
of nylon or other suitable material to receive
respective shafts 20 and 22.
Valve cylinders 24, 26 are moulded from
a suitable material such as polyurethane directly
onto the shafts 20, 22 and are prevented from
rotation relative to the shafts by respective
flats 28, 30 on the shafts. In a situation
where corrosive material is likely to be encountered,
the shafts 20, 22 are preferably made from stainless
lS steel. The upper ends of the shafts are provided
with square sections 32, 34 on which respective
pinion gears 36, 38 preferably made of nylon are
mounted.
The gears are held in position on the
shafts by means of nutc 40 and washers 42. The
gears 36, 38 are identical and are of such
diameter that their teeth intermesh to ensure
that the shafts 20, 22 will rotate at the same
speed as each other and in opposite directions.
The gears are driven by means of a rack 44 which
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may be made from stainless steel and which is
moved to and fro along its axis to vary the
valve opening by means of a fluid operated
ram, such as an air cylinder, or by other
suitable means.
As best shown in Figures 1 and 4, each of
the valve cylinders 24, 26 has a groove of
varying cross-section formed around its periphery.
Each groove has a minimum depth at point 46
(see Figure 4) and a maximum depth at point 48.
The cross-section of each groove is preferably
semi-circular and the meshing of the gears 36,
38 is so arranged that points 46 of the respective
valve cylinders are in contact when the valve is
I5 closed.
By operation of the rack drive to rotate
gears 36, 38 shafts 20, 22 and valve cylinders
24, 26, it is possible to produce an in-line
flow aperture 50 of circular cross-section
having a diameter from zero to a maximum value
equal to the internal diameter of the input-output
passages 52.
To seal the valve cylinders 24, 26 in
the valve chamber 12, the surface of valve
chamber lining 13 which contacts the valve
.,
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cylinders 24, 26 has a series of serrations
53 formed in it parallel to the axes of the
shafts 20, 22. The relative dimensions of
the valve cylinders 24, 26 are selected to
provide a slight pressure between the crests
of the serrations and the external surfaces
of the valve cylinders.
The sealing of the valve cylinders
24, 26 in the valve chamber is also assisted
by the provision of annular sealing projections
54 on the upper and lower surfaces of each
valve cylinder 24, 26, the projections preferably
- exerting a small pressure against the adjacent
surfaces of the lining.
lS The valve may be connected into a flexible
pipe by cutting the pipe and connecting the cut
ends to the valve casing by means of appropriate
couplings or by the provision of flanges.
It will be clear that the use of the valve
is not restricted to flexible pipes and that it
can be used where appropriate with rigid metal
pipes.
The valve of the invention has application
in many different industries for many different
purposes but, in the case of the present
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applicant, the valve is seen as being useful
mainly in situations where a liquid carrying
lime is to be transported, for controlling
the tails being discharged from a flotation
cell and in concentrate filter feed lines.
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