Note: Descriptions are shown in the official language in which they were submitted.
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IMPROVED VALVE ASSEMBLY
The present invention relates to an improved valve
assembly, in particular for use in household coffee
machine water circulation conduits.
Valve assemblies are known, as described for example
in Patent W002088580, which comprise a casing defining a
fluid flow cavity; and a valve housed inside the casing
to separate a first and a second environment of the flow
cavity hermetically when the pressure in the first
environment exceeds the pressure in the second
environment by an amount above a predetermined threshold
value.
More specifically, the valve substantially comprises
a disk-shaped base member having an opening to permit
fluid flow between the first and the second eravironment
separated by the base member; and an elastically
deformable ring co'operating with the base member to fix
the base member hermetically inside the cavity. The valve
also comprises a flexible shutter having, on the side
facing the first environment, a membrane portion which,
by virtue of fluid pressure, cooperates elastically with
the opening to separate the first and second environment
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hermetically.
As stated, valve assemblies of the above type permit
fluid flow between the first and second environment when
the difference in pressure between the first and second
environments is less than or equal to the predetermined
threshold value.
To this end, the base member also comprises, on the
side facing the first environment, a recess communicating
with the opening and selectively engageable by the
membrane portion to permit fluid flow through the base
member for pressure difference threshold values depending
on the geometry of the recess.
Though efficient and reliable, valves of the above
type still leave room for improvement. In particular, a
need is felt to reduce the number of component parts, so
as to reduce the number of moving parts and simplify
component machining and assembly.
It is an object of the present invention to provide
a valve assembly designed to satisfy the aforementioned
need in a straightforward, low-cost manner.
According to the present invention, there is
provided a valve assembly as claimed in Claim 1.
A preferred, non-limiting embodiment of the present
invention will be described by way of example with
reference to the accompanying drawings, in which:
Figure ]. shows an axial section of a valve assembly
in accordance with the present invention and in the
closed position;
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Figure 2 shows a section along line II-II in Figure
1;
Figure 3 shows an axial section of a further
embodiment of the Figure 1 valve assembly in the closed
position;
Figure 4 shows a section along IV-IV in Figure 3;
Figure 5 shows a top plan view of a detail in Figure
1;
Figure 6 shows a side view of the Figure 5 detaii.
With reference to Figures 1 and 2, number 1
indicates as a whole a valve assembly in accordance with
the present invention, and particularly suitable for use
in household coffee machine water circulation conduits.
Valve assembly 1 comprises a casing 2 defining a
fluid flow cavity 3; and a valve 4 housed hermetically
inside cavity 3 to control flow between two separate
environments 5, 6 of cavity 3 separated by valve 4.
More specifically, casing 2 has an axis A, and
comprises a body 7 and a body 8, which extend axially on
opposite sides towards environments 5 and 6 respectively.
Body 7 comprises an axial fluid conduit 9; and an
axial end portion 10 larger radially than conduit 9 and
Connected to conduit 9 by a radial wall 11.
Similarly, body 8 comprises an axial fluid conduit
12 extending on the opposite side to conduit 9; and an
axia], end portion 13, which is larger radially than
conduit 12, is fixed to portion 10 of body 7 in a manner
not shown, and is connected to conduit 12 by a radial
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wall 14.
Valve 4, shown in more detail in Figures 5 and 6, is
housed coaxially inside casing 2, and comprises a portion
15 which cooperates hermetically with portion 10 of body
7 and permits fluid flow between environments 5 and 6.
More specifically, at its radially outer end,
portion 15 comprises a toroidal portion 18 cooperating
radially and hermetically with portion 10; and an annular
portion 16 no larger axially than portion 18, and
connected at its radial ends to portion 18.
At the join between portion 16 and portion 18,
portion 15 also comprises a number of - in the example
shown, four - axially through openings 23 permitting
passage between environments 5 and 6.
More specifically, openings 23 are equally spaced
angularly about axis A, and each comprise a contour
defined by two radially opposite circumferential portions
31 connected by two angularly opposite radial portions
32.
Portion 15 is bounded axially towards environments 5
and 6 by respective end surfaces 20 and 21. More
specifically, end surface 21 cooperates with a number of
- in the example shown, three - appendixes 22 equally
spaced angularly and projecting axially from wall 14
towards valve 4 to hold valve 4 in position axially.
Valve 4 also comprises a portion 19 varying in
configuration to permit/prevent communication between
environments 5 and 6.
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Portion 19 advantageously also cooperates
hermetically with casing 2, on the side facing
environment 5, to prevent environments 5 and 6 from
communicating fluidically through openings 23.
5 More specifically, at portion 16, portion 19 extends
from portion 15 towards environment 5 to define, with
body 7, a cavity 30 which is cut off fluidically from
openings 23 when the pressure in environment 6 exceeds
the pressure in environment 5 by an amount above a
predetermined threshold value P. Conversely, cavity 30 is
connected fluidically to openings 23,' to permit fluid
flow through openings 23, when the pressure in
environment 6 exceeds the pressure in environment 5 by an
amount below predetermined threshold value P.
i5 More specifically, portion 19 comprises a radially
outer, truncated-cone-shaped profile 24 connected to
portion 16 on the opposite side to environment 5; a
radially inner, concave profile 25; and a circular axial
end 26 cooperating hermetically with wall 11 of body 7.
More specifically, profile 24 diverges towards
environment 5, and, together with profile 25, defines end
26 on the environment 5 side.
Profile 25 comprises a curved portion 27 at portion
16; and a truncated-cone-shaped portion 28 interposed
23 axially between portion 27 and end 26, and diverging
towards environment 5.
More specifically, profiles 24 and 25 are shaped so
that portion 19 has an axial section tapering from
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portion 15 to end 26.
Cavity 30 is therefore bounded by profile 25 of
portion 19 and by wall 11, and is open at conduit 9.
Portions 19 and 15 are defined integrally by one
body and made of flexible material. More specifically,
portions 19 and 15 are preferably made of an organic
polymer compatible with use in contact with food
products, e.g. silicone.
In actual use, when the pressure in environment 6
exceeds the pressure in environment 5 by an amount above
threshold value P, end 26 adheres to wa11. 11 of body 7,
so that cavity 30 is cut off flui.dioally from openings 23
to separate environments 5 and 6 in fluidtight manner.
Conversely, when the difference in pressure between
environments 6 and 5 is less than or equal to threshold
value P, the fluid in cavity 30 detaches end 26 from wall
11, so that cavity 30 is connected fluidically to
openings 23 to allow fluid flow between environments 6
and 5; which characteristic may be used to prevent fluid
stagnating in environment 5 when the pressure in
environment 5 falls as a result, for example, of a
delivery pump connected to cavity 3 being turned off.
Threshold value P, corresponding to the maximum
pressure difference value at which fluid flows both ways
through cavity 3, may obviously be varied by varying the
shape of portion 19.
With no change in the shape of portion 19, threshold
value P may obviously also be varied by varying the axial
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position of wall 11 with respect to end 26.
More specifically, moving wall 11 axially away from
end 26 reduces threshold value P, eventually to zex'o; in
which latter case, valve assembly 1 permits flow from
envirpnment 6 to environment 5 for any pressure
difference between environments 6 and 5.
Conversely, moving wall 11 axially towards end 26
increases threshold value P.
The Figure 3 embodiment shows a valve assembly 1'
similar to valve assembly 1, and the component parts of
which are indicated, where possible, using the same
reference numbers as for the corresponding parts of valve
assembly 1.
Valve assembly 1' differs from valve assembly ]. by
wall 11 comprising a groove 35, which imparts an
undulated shape to wall 11. Groove 35 cooperates with end
26 to separate environments 5 and 6 hermetically, when
the pressure in envirpnment 6 exceeds the pressure in
environment 5 by an amount above threshold value P, and
is disengaged by end 26, to permit fluid flow, when the
pressure difference between environments 6 and 5 is below
threshold value P.
More specifically, groove 35 comprises a number of -
in the example shown, three - contiguous lobes 36 equally
spaced angularly and lying in a plane set back towards
environment 5 with respect to wall 11.
With particular reference to Figure 3, when the
pressure in environment 6 exceeds the pressure in
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environment 5 by an amount above threshold value P, end
26 of portion 19 adheres to groove 35, at each lobe 36,
so that cavity 30 is cut off fluidically from openings 23
to separate environments 5 and 6 in fluidtight manner.
Conversely, when the pressure difference between
environments 6 and 5 is less than or equal to threshold
value P, end 26 does not adhere to groove 35, so that
cavity 30 is connected fluidically to openings 23 to
permit fluid flow between environments 6 and 5.
Threshold value P therefore depends, not only on the
shape of portion 19 and the axial position of wall 11
with respect to port9.on 19, but also on the shape of
groove 35.
The advantages of valve assembly 1, 1' according to
the present invention will be clear from the foregoing
description.
In particular, valve assembly 1, 1' is formed in two
parts, thus reducing the number of moving parts and
relative machining and assembly costs.
Clearly, changes may be made to valve assemblies 1,
11 according to the present invention without, however,
departing from the protective scope of the accompanying
Claims.
