Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
The present invention relates to hoses for use with
perostaltic pumps.
The hoses used with peristaltic pumps are subjected
to much strain and constitute wearing parts which need to
be replaced rather often. It is therefore necessary to
provide hoses which will be-tter withstand the repeated
strains to which they are subjected. Such hoses should
also, on the one hand, wear longer, even though with the
disadvantage that their suction capacity reduces rapidly
and, on the other hand, they should be adaptable to the
conveying of a large number of products.
It is the object of the present invention to fulfill
all these requirements by proposing a new hose for peris-
taltic pumps which is constituted by a tubular central
core produced with no junction plane in rubber or
in elastomer, by a first reinforcement placed on the outer
surface of the core, which is in the form of a gauze with
meshes between 0.5 and 1 mm, oriented so as to form an
angle of between 30 and 60~ (and preferably 451 wlth the
longitudinal axis of the core, by a layer of non-vulcan-
izable gum deposited on the first reinforcement, by a
second reinforcement placed over the said layer of gum,
and by an external sheathing produced with no junction
plane, in rufi~er.
According to a preferred embodiment of the invention,
the thickness ratio between the different constituents of
the hose is such that the reinforcements and the gum layer
are substantially situated at one third of the total
thickness of the hose as measured from the inner surface
of the core. Also, the thickness of the gum layer willadvantageously be equal to 1 mm.
The hose according to the invention further com-
prises at least one end flange, which is produced separate-
~ n rubber, with no junction plane, and is fitted
by bonding-vulcanization on one end of the hose. In the
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case where only one flange is fitted on the hose, said
latter will be advantageously equipped with a stop-collar
in rubber, with no junction plane, said collar
forming a support for a removable flange and being ~itted
by bonding-vulcanization on the other end.
The hose according to the invention finally compri-
ses a guiding ridge which is added on along one of its
external generating lines by bonding-vulcanization.
The invention will be more readily understood on
reading the following description with reference to the
accompanying drawings in which :
- Figure 1 is a longitudinal cross-section of a
hose according to the invention;
- Figure 2 ~s a cross-section along II-II of
Figure l;
- Figure 3 is an external partial view of the cora
equipped with its first reinforcing gauze;
- Figure 4 is a longitudinal cross-section of the
~ complete hose equipped with its collar, flange and
ridge;
- Figure 5 is a cross-section along V-V of Figure 4,
Referring first to Figures 1, 2 and 3, these show
that the hose according to the invention comprises,
starting from the inside, a central core 1, made of
natural or synthet~c rufifier, w~th no
junction plane, i.e. produced by extrusion or rovinq, and
not by molding. It may equally be produced from an elas-
tomer (chloroprene, butylnitrile, a product known under
the trademark "Hypalon"...). The said core is then covered
with a first reinforcement which is in the form of a
gauze of~polyamide, rayon, or a wire netting,... with
meshes of between 0.5 and 1 mm. Said gauze 2 is oriented
with respect to the axis 3 of the tubular core 1 so that
its warps and`wefts form an angle A and B of between 30
and 60 with said axis. Preferably, the angle will be 45.
On this first reinforcement is applied a layer 4 of non-
vulcanizable gum and a second reinforcement 5. The texture
of this reinforcement will be selected in relation to the
characteristics required for the hose and can be identical
to that of the first reinforcement. The resulting assembly
is then covered with an external sheathing ~ in natural
rubber. A composite hose is thus obtained which shows a
number of advantages in view of the hoses known up to now.
For example, the first reinforcement enables the life of the
hose to be, lengthened by restrainin~ the wearing -down of
the core through internal abrasion at the end points of
the area squeezed by the passage of the rollers, which
abrasion can lead to the hose becoming perforated or
breaking. The said first reinforcement further permits limit-
ation f the stresses inside the entire hose assem~ly and
inside the core, especially by forming a holding member
for the material which tends to be carried away by the
rollers squeezing it. The non-vulcanizable gum constitutes
a securing agent, securing the first reinforcement to the
core, the second reinforcement and the external sheathing
to the inside part, and this due to its great plasticity
which enables it to pass through the meshes of the gauzes
and due to its bonding qualities which make it the bonding
element of the entire hose. This gum also protects the
hose against shearin~. Finally, the choice of natural
rubber for the external sheathing is determined by the
high qualities of this material from the point of view
of its elasticity and,of its ready adherence to the remov-
able elements.
It should also be noted that the thicknesses ofthe different constituents of the hose have been deter-
mined so that the gum and the two reinforcements are
situated at about one third of the overall thickness of
the hose, as measured from its internal face. This dis-
94
position is the one which when tested has given the bestresults. Moreover, the thickness of the gum does not ex-
ceed 1 mm, this being the optimal thickness to preser~e
all the qualities of the gum without suffering any of the
drawbacks (amongst which, too great a plasticity which
would affect the behavior of the hose).
Figures 4 and 5 show a hose such as described here-
inabove with the same references but eq~ipped with re-
movable elements. One of these elements is an end flange 7
produced by injection (i.e. with no junction plane) in
natural rubber, and secured by bonding-vulcanization on a
cut-in portion at the end of the hose 1 to 6, At another
end of the hose has also been fitted by bonding-vulcani-
zation a stop-collar 8, which is equally produced by
injection, therefore with no junction plane. Said collar
is provided with a groove 8a in which can be fitted a
removable flange, not shown. Such flange is fitted in
by way of notches provided both in the external side of
the collar 8 and in the flange, in the same was as a
socket type fitting.
Finally, over the whole length of an external
generating line of the hose, is fitted a rib 9 or ridge,
the function of which is to keep the hose centered inside
the pump body. Said ridge is also bonded and vulcanized
and is made of natural rubber.
Besides the advantages mentioned hereinabove, it
will be noted that a hose, produced this way, is more
"nervous", i.e. it retains a better elasticity when in
service, the permanent deformation caused by the
squeezing by the rollers of the pump being limited~ As a
result, the volume of the chamber of the pump is better
supported and the flow is more stable, the shape recove-
ries are more rapid, this permitting higher speeds of
rotation or a better filling of the chambers when vis-
cous products are pumped up, hence a better flow rate,
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It is also possible with the hose according to theinvention to obtain a higher delivery pressure, And
since the hose is produced wlth no junction planes in
any of its constituents, it is more homogeneous and
therefore stronger than a hose produced by assembly or
by folding of a flat piece,
It should also be noted that the material cons-
tituting the core can be selected and be-for example an
elastomer suitable for the product conveyed. Considering
the characteristics of these elastomers, it would have
been impossible to use them as sole constituent of the
hose because, used in very thick layers, these materials
would not withstand the wear and tear imposed upon them,
Finally, the hose is designed so that, as shown in
Figure 4, only the core is in contact with the pumped
product taccounting for the presence of the known
connecting sleeves). Therefore, whatever thè product,
the end members of the hose are made of natural rubber.
It will be advantageous for the length of the hose to be
such that once fitted in the pump body, it is slightly
squeezed at both ends, this preventing r~sk of the
removable parts detaching themselves.
The invention finds an advantageous application in
the production of pumps. It is in no way limited to the
description given hereinabove, but on the contrary cover
any variants that can be brought thereto without depart-
ing from the scope or the spirit thereof.
