Note: Descriptions are shown in the official language in which they were submitted.
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SPREADER ASSEMBLY FOR A BULK MATERIAL SPREADER VEHICLE
The present invention relates to a spreader
assembly for a vehicle for spreading anti-icing and/or
abrasive material in bulk, e.g. salt, chlorides in
general, sand, or grit on a road surface.
A spreader vehicle normally comprises one or more
hoppers containing the solid material in bulk; possibly
tanks containing liquid material for mixing with the
solid material; and one or more spreader assemblies,
which are fed with solid material from the hopper, and
spread it on the road surface.
As is known, anti-icing materials, such as salt,
are spread on a road surface to prevent ice forming, and
moving vehicles from losing grip; and abrasive
materials, such as grit, are spread to ensure grip, even
on icy road surfaces.
A spreader assembly normally comprises one or more
feed conduits for drop-feeding salt from the hopper; and
one or more rotating disks with blades, located
downstream from the feed conduits to spread the salt.
The salt, expelled by centrifugal force, covers a spread
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area that fans out from the spreader assembly in the opposite
direction to the travelling direction of the vehicle.
For effective spreading, the spread area is conveniently
controlled by the operator from the vehicle cab.
To improve the anti-icing effect, the solid material may
be expelled moistened with liquid material.
To ensure effective, even anti-icing, it is important,
when liquid material is used, to prevent the moist salt from
forming into large lumps spread too far apart.
WO-A1-2005033417 describes a spreader assembly defining a
salt-liquid mixing chamber, and comprising a first number of
rotary blades to mix the liquid and salt, and a second number
of'blades which receive and spread the moist salt onto the road
surface.
The mixing action of the blades, however, fails to solve
the problem of lumps forming inside the mixing chamber. It is
an object of the present invention to provide a spreader
assembly for a bulk material spreader vehicle, designed to
eliminate the aforementioned drawbacks.
According to an aspect of the invention, there is provided
a spreader assembly for a vehicle for spreading bulk material,
the spreader assembly defining a cavity for receiving the bulk
material; and a rotary disk rotating about an axis and
supporting a number of blades for spreading said bulk material
from said cavity, and expulsion means for directing the bulk
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material from said cavity to said number of blades; and feed
means for supplying a liquid, in that said feed means (26)has
an outlet so located as to moisten said bulk material with said
liquid as said bulk material leaves said cavity along a clear
path produced by the action of said expulsion means (24) when
said material is already detached from said expulsion means
(24).
According to a further aspect of the invention, there is
provided a method of moistening bulk material by means of a
spreader assembly as claimed in any one of Claims 1 to 14, and
comprising a step of moistening said bulk material with a
liquid; the method being characterized in that said moistening
step is performed as said bulk material is directed along a
clear path produced by the action of said expulsion means.
A preferred, non-limiting embodiment of the present
invention will be described, purely by way of example, with
reference to the accompanying drawings, in which:
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Figure 1 shows a rear view of a spreader vehicle
and a spreader assembly in accordance with the present
invention.
Figure 2 shows a view in perspective of the Figure
1 spreader assembly;
Figure 3 shows a larger-scale view in perspective
of a portion of Figure 2 sectioned along vertical plane
111-111 in Figure 2.
Figures 1 and 2 show a spreader vehicle 1 for
spreading bulk material, e.g. salt, and comprising a
hopper 2; and a spreader assembly 3 fitted to vehicle 1
to spread salt onto a road surface.
Spreader assembly 3 comprises a feed conduit 4 with
an inlet 5 positioned to receive the salt from hopper 2;
a frame 6 connected rigidly to an end portion 7 of feed
conduit 4, at the opposite axial end to inlet 5; and a
bladed spreader disk 8 fitted to frame 6 and rotating
about a substantially vertical axis A.
Spreader assembly 3 is preferably fitted to vehicle
1 by means of feed conduit 4, which is designed to
withstand static and dynamic stress produced, for
example, by the mass of frame 6 and spreader disk 8.
Spreader assembly 3 also comprises a casing 9
fitted in rotary manner to frame 6 in an intermediate
axial position between end portion 7 and spreader disk
8; and a preferably hydraulic rotary motor 10 fitted to
frame 6, on the opposite axial side of spreader disk 8
to end portion 7.
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More specifically, frame 6 comprises a rail 11 to
guide rotation of casing 9 about an axis preferably
coincident with axis A.
Rotary motor 10 is fitted to spreader disk 8 in
such a manner as to be protected against the incoming
salt from feed conduit 4.
Rotary motor 10 is conveniently powered by conduits
12 fitted to frame 6 and connectable to the hydraulic
circuit of vehicle 1, so the rotation speed of spreader
.disk 8 can be driver-controlled from the control panel
inside the vehicle cab.
Figure 3 shows a more detailed view of frame 6,
which comprises an arm 13 having an end portion 14
crosswise to axis A and underneath spreader disk 8; and
a top bracket 15 over casing 9.
Arm 13 preferably also comprises a portion 16
parallel to axis A and connected rigidly to bracket 15.
In a preferred embodiment, arm 13 has a hollow cross
section to house at least part of the length of conduits
12 and protect them against the spread material and any
debris thrown up off the road surface by vehicle 1
travelling at high speed.
Bracket 15 defines a surface substantially
perpendicular to axis A, and is connected rigidly to end
portion 7 of feed conduit 4 by two plates 17.
Plates 17 are also connected rigidly to rail 11,
which is preferably annular and surrounds end portion 7
of feed conduit 4.
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,
To cooperate with rail 11, casing 9 comprises a
number of pins P (Figure 2) equally spaced angularly,
and which slide tangentially inside a groove 18 defined
by rail 11 and preferably concentric with axis A.
Casing 9 comprises a tubular portion 19, preferably
coaxial with axis A; and a cover portion 20 extending
radially outwards from an end portion of tubular portion
19, and preferably larger in diameter than spreader disk
8.
Tubular portion 19 is large enough axially to
define a cavity 21 closed at the bottom by spreader disk
8, and open towards feed conduit 4 to receive the salt.
Cover portion 20 defines, with spreader disk 8 and
tubular portion 19, an annular volume 22, which
0 communicates with cavity 21 through an opening 23
defined at least partly by tubular portion 19 and
located downstream from feed conduit 4. Annular volume
22 is open radially to permit salt spreading by spreader
disk 8.
In the embodiment shown, for example, the perimeter
of opening 23 is closed by spreader disk 8.
Spreader disk 8 comprises a first number of fixed
blades 24 inside cavity 21; and a second number of
blades 25 integral with blades 24 and located radially
2.5 outwards of tubular portion 19.
Spreader assembly 3 preferably also comprises a
tank 26 for distributing known liquid solutions on the
salt to enhance its anti-icing effect.
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More specifically, tank 26 defines a storage volume
27 filled through an inlet 28 by a pipe connected to a
circuit on vehicle 1; and an outlet 29 over opening 23.
Tank 26 is preferably fixed with respect to casing 9,
and is mounted inside annular volume 22.
Spreader assembly 3 also comprises an actuating
device for rotating casing 9 and setting opening 23 to
the desired angular position.
The actuating device preferably comprises a rotary
W motor 30 fitted to bracket 15; and a sector gear 31
fixed with respect to casing 9 and meshing with a pinion
connected to rotary motor 30. Alternatively, the
actuating device comprises a hydraulic or electric
actuator.
Spreader assembly 3 preferably also comprises one
or more angular position sensors, which determine the
angular position of opening 23, and transmit a signal to
an instrument in the driver's cab to enable the driver
to control orientation of the salt spread area.
The angular position sensor is preferably a
discrete type, and comprises a counter 32 with a movable
rod 33, which cooperates with a number of angularly
equally spaced projections fixed angularly with respect
to casing 9. Alternatively, the sensor may comprise an
encoder.
Spreader assembly 3 according to the present
invention operates as follows.
As vehicle 1 travels along the road, the driver
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activates a known feed device to feed salt from hopper 2
to inlet 5 of feed conduit 4.
The salt flows into cavity 21, where it is expelled
- evenly and always along the same trajectory,
regardless of the type, quantity, and quality of the
material being spread - through opening 23 into annular
volume 22 by blades 24.
As it flows through opening 23, the salt is
moistened with the solution from tank 26, which
overflows from storage volume 27 to form a homogenous
film.
The salt is therefore moistened after it leaves
blades 24, and cannot flow back into cavity 21.
Preferably, the salt is moistened, after it leaves
M blades 24, along a path through opening 23, so that the
moist grains no longer come into contact with blades 24
and/or do not remain inside cavity 21.
Blades 25 then spread the salt onto the road
surface.
To orient the spread area, e.g. to salt the
overtaking lane when the vehicle is travelling along the
main lane, the driver operates the mechanically or
electrically controlled actuator 30 to move opening 23
or the whole assembly, and controls the position of
opening 23 by means of the angular position sensor.
Blades 24 therefore substantially define an
expulsion device for feeding the salt from cavity 21
through opening 23 into annular volume 22.
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Moreover, opening 23 defines a specific flow
section defining the cross section of salt flow onto
blades 25, which are therefore supplied with salt flow
of regular, constant cross section, by virtue of the
forced expulsion performed by the blades on the inner
disk. This characteristic provides for achieving a
precisely shaped spread area, regardless of the type,
condition, or quantity of the material being spread.
Blades 24 also provide for disposing of any salt
accumulating inside cavity 21.
Spreader assembly 3 according to the present
invention has the following advantages.
Moistening the salt along a clear path to blades
25, i.e. when the grains are already detached from
blades 24, prevents the moist salt from remaining inside =
cavity 21 and being kneaded by blades 24.
Opening 23 defined by the rotary casing 9 provides
for obtaining a precise, adjustable spread area.
Blades 24 provide for smooth expulsion of the salt
from cavity 21, regardless of the type, condition, or
quantity of salt involved.
Casing 9 being lightweight and easy to control,
spreader assembly 3 is compact and lightweight, and can
be connected to vehicle 1 by means of feed conduit 4.
Clearly, changes may be made to spreader assembly 3
as described and illustrated herein without, however,
departing from the scope of the present invention as
defined in the accompanying Claims.
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For example, outlet 29 may be located immediately
upstream from opening 23, so as to moisten the salt as
it is about to flow out of cavity 21 towards blades 25.
In which case, the liquid and salt are mixed inside
cavity 21, but not by blades 24. Moreover, the salt is
directed towards opening 23 by centrifugal force, and
cannot flow back into cavity 21.
Generally speaking, outlet 29 is so located that
the salt is moistened as the individual grains travel
towards opening 23 along a clear trajectory produced
substantially by centrifugal force, i.e. when the grains
are already detached from blades 24.
Preferably, the salt is moistened along a path
defined between the radial ends of blades 24 and blades
25 through opening 23, and the moist grains do not
travel through the expulsion device.
For example, blades 24 may be radially smaller than
tubular portion 19, and outlet 29 may be located
adjacent to opening 23, in the gap between blades 24 and
tubular portion 19.
Alternatively, outlet 29 may be located some
distance from opening 23, and the liquid may be
pressurized to strike the salt when the grains are
already detached from blades 24 and directed towards
opening 23.
Opening 23 may also be fixed with respect to frame
6.
