[0001] The invention refers to a deshydrating screw press with two or more helical elements,
which avoids partial interference zones of the spirals on the product to treat. By
using the above mentioned elements side by side, a combined effect of complete conical
interference is obtained, in the interspace between shafts, with a push of the two
intersecting spirals, with movement in opposition, which compels the axial advancement
of the product.
[0002] The screw presses are used to deshydrate fibrous materials containing liquid; they
are particularly used in the sugar beat treatment, in fodder deshydratation, to extract
oils and produce meals for fodders from food stuff recovers such as fish and other.
The said presses use two or more helical elements which let the product advance from
an end, pressing it inside a filtering cage from which the liquid gets out steadily,
while the anhydrous residue is discharged from the other end. The present presses
use helical elements with two different diameters and with a fitting in a truncated
cone shape between these elements. This causes a bicylindrical interference space
of the spiral filtering cage, which gives rise to non-interference zones, as well
as other zones with limited interference of the spirals. This intervention difformity
and even of non-intervention of the spiral does not grant a uniformity of pressure
of the product and causes losses of delivery. In particularly, when the helical elements
are used side by side, zones of limited and even of no interference of the spirals
occur, where difficulties can be noted in letting the product advance. Consequently,
this one tends to stagnate and in particular, owing to the lateral over-stressing
caused by the spirals in these zones, heaping may occur with relevant heavy problems.
Moreover the difform advancement of the product causes void spaces which crush and
damage the anhydrous residue. Therefore, one can affirm that the speed allowed by
the installation cannot be completely made most of, because it must be steadily in
conformity with the product to treat and production must steadily be checked to enable
timely intervention.
[0003] These inconveniences are obviated by the present invention which ensures uniformity
in the pressing action of the helical element spiral that is steadily operating with
space interference to wall limit. In the interspace between the shafts of the helical
elements fitted side by side, the system allows the combined effect of complete interference
with push of the intersecting parts of the in opposition turning spirals which compels
the axial forward move of the product. In connection, since there are no zones without
or with limited interference, the system enables to adjust the delivery to the speed
of the propellers. In particular, the smaller space existing in the central intermediate
part between the two helical elements, carried out according to the invention, in
comparison with the one existing in the already mentioned union with truncated-cone
interference, avoids heap-of pro duct; on the contrary, since the two intersecting
spirals operate with complete interference up to the wall limit of the two shafts,
the gradual axial move of the product is ensured.
[0004] Substantially, the product to deshydrate in advancing movement is pressed by the
rotating motion of two or more screw elements with conical shaft 1 and also conical
spiral 2 - total and regular - to operate in a correspondence space to wall limit
of the filtering cage 3. If the helical elements with regular total conical interference
are used side by side, since the lifting upwards of the spiral 2 is in them in accordance
with a like section reduction 4 of its shaft 1, each spiral is allowed to work with
profile continuity up to wall limit of the shaft of the other helical element, thus
avoiding zones of either no or limited interference on the treated product in the
intermediate space between the shafts. Moreover,the movement in opposition of the
two or more pressing elements causes a combined effect of complete interference given
by the two reciprocally intersecting spirals which compels the axial advancing motion
of the product. The filtering cage used for the press with two or more helical elements
consists of two components 5 and 6 connected on slanting converging lines 7 and 8
fitted on interference limit of the two or more intersected spirals.
[0005] An execution version of a deshydrating press, with two helical helements fitted
side by side, is illustrated in the schematic drawings of table 1. With reference
to this table, fig. 1 is the vertical longitudinal section of the press with side
view of a helical element to point out the conical interference spiral which operates
up to wall limit of the filtering cage. Fig. 2 is a partial view of horizontal longitudinal
section of the press, with view from above of the two flanked helical elements to
show the intermediate zone between the two shafts where the interference of the two
spirals can be noted, each one of which is working up to wall limit of the other one's
shaft. Fig 3 is a view of the press transversal section to show the interference
fields of the two spirals.
[0006] For the press operation, motor 9 is started which, by means of transmission 10 with
pulleys 11 and 12, transmits the movements, through reducer 13 on shafts 14, to the
helical elements with conical shafts 1 and conical spirals 2. The biconical filtering
cage is kept, by the modular grupping U-bolts 15 and 16, in the frame 17 on base 18
and is contained in carter 19 complete with inspection lids 20.
[0007] In the executions, the use of helical elements is foreseen with constant profile
shafts and spirals. The components may fitted in different connections and replaced
with other technically equivalent ones.
1) Deshydrating screw press, characterized by the fact that the used helical elements
with total and constant conical interference are fitted side by side, and since the
lifting of the spiral (2) is in them in relation with the like reduction of the shaft
(1) section (4), each spiral is allowed to operare with profile continuity up to wall
limit of the shafts of the other helical conical elements. In this way, the presence
of zones with no or limited interference on the treated product is avoided. Moreover,
the movement in opposition of the two or more pressing elements causes a combined
push antiturning intervention given by the two or more intersecting conical spirals
with constrains the axial forward movement of the product.
2) Deshydrating screw press, as per claim 1, characterized by the fact that the filtering
cage used for a press with two or more helical elements, consists of two of more
components (5 and 6) connected on converging slanting lines (7 and 8) at interference
limit of the two intersected spirals.
3) Deshydrating screw press, as per claim 1, characterized by the fact that the pressing
of the product to dehydrate during advancing is performed by the rotating movement
of either one or more screw elements with conical shaft (1) and conical spiral (2)
with total constant conical interference in order to operate in space of correspondence
at wall limit of biconical filtering cage (3).
