FIELD OF THE INVENTION
The present invention relates to a mechanical descaler in wire rod drawing
plant to remove oxide layers on outer surface of hot rolled wire rods.
BACKGROUND OF THE INVENTION
Hot rolled wire rods used as a raw material for wire drawing industries have a
distinct disadvantage due to presence of scale on their outer surface. The
removal of scale is a pre-requisite for smooth wire drawing.
The methods used for the descaling of wire rods include pickling, reverse
bending etc. A mechanical descaler is one such means that is used for this
purpose. A mechanical descaler is used in wire drawing industry, where wire
rods are drawn into wires with diameter lower than that of the wire rods. It is
based on the principle of reverse bending. In wire drawing industries,
mechanical descalers are placed before the wire drawing machine. A number
of patents related to wire drawing machine are available such as U.S. patent
No. 5097688 to Taylor et al. [1]; U.S. patent No. 6000656 to Tailor et al. [2];
and many others [3,4].
Mechanical descalers used for descaling of wire rods generally comprise of
metallic rollers (pulleys) The wire rod passes over these rollers and bending
takes place. This bending causes breaking and peeling off of the scales from
wire rod surface. There are varieties of mechanical descalers available today
which vary in terms of number of rollers employed, sizes of these rollers and
their orientations with respect to each other.
The challenges with the existing descalers are 360O coverage of the wire rod
surface and high number (five and above) of pulleys employed for descaling.
In addition to this, few descalers, which have lower numbers (two to four) of

rollers, are retrofitted with air or water jets, brushing units etc. for complete
removal of the scales from the surface of the wire rods. The function of the
rollers in mechanical descalers with lower number (e.g. two) of rollers is to
break the scales. The peeling off of the scales is carried out either by
different kind of jets or brushing units. A mechanical descaler with two rollers
for breaking of scale and a jet for removal of scale is covered in U.S. patent
No. 4333275 A to Bernot et al. [5] and many other patents [3,4].
The mechanical descalers used today either employ high number of rollers or
low number of rollers and addition of other different arrangements for the
purpose of descaling. So an invention for the purpose of descaling with low
number of rollers without any other arrangement is unaddressed. The current
invention is a way forward in this direction.
OBJECTS OF THE INVENTION
It is therefore an object of the invention to propose a mechanical descaler in
wire rod drawing plant to remove oxide layers on outer surface of hot rolled
wire rods, which use low number of rollers without auxiliary units for
generating air or water jet and brushing.
Another object of the invention is to propose a mechanical descaler in wire
rod drawing plant to remove oxide layers on outer surface of hot rolled wire
rods, which is simple in structure, efficient, and allows casing mounting of the
rollers.

SUMMARY OF THE INVENTION
Accordingly, there is provided a mechanical descaler in wire rod drawing plant
to remove oxide layers on outer surface of hot rolled wire rods. A mechanical
descaler is used in wire drawing industry, where wire rods are drawn into
wires with diameter lower than that of the wire rods. The mechanical
descalers of the invention consists of rollers for the purpose of descaling.
The rollers used in this invention are mounted on cylindrical shafts each
supported by a pair of bearings. One end of these shafts is attached to flat
plates with through holes. These holes enable the pulley cum shaft assembly
to get mounted on a flat surface. All these assemblies are mounted on a
metallic frame. The orientation of the rollers with respect to each other is
such that no additional arrangements are required for the complete removal
of scale from wire rod surface. This orientation causes descaling from the
surface of the wire rod in successive zones along the peripheral direction as
the wire rod passes from one roller to another. These successive zones
covers complete 3600 of the surface of the wire rod.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Fig.1 shows a cylindrical pulley which has grooves cut on its inner and outer
surface.
Fig.2 shows half portion of a ring split symmetrically along circumferential
plane.
Fig.3 shows a cylindrical shaft attached to a flat plate with circular holes in
it.

Fig.4 shows assembly of the pulley and the ring on the cylindrical shaft with
one end of the shaft attached to a flat plate.
Fig.5 shows an assembly of three pulleys on a frame.
DETAILED DESCRIPTION OF THE INVENTION:
Mechanical descaler is a single unit device. It consists of a plurality of pulleys
for example three which are assembled together on a frame.
The first pulley (1) is a hollow cylindrical object with grooves cut on the inner
and outer curved surfaces. The pulley (1) has one groove (2) of uniform
depth cut on its outer surface throughout its periphery. Three grooves (3,4,5)
are cut on the inner surface. Grooves (4) and (5) have same diameter. The
pulley (1) with half of its portion cut by a lateral plane is shown in figure – 1.
Metallic alloy has been used for fabrication of the pulleys.
A circular ring (6) with its symmetric half cut by a lateral plane is shown in
figure – 2. The outer surface of the ring has a particular profile as pointed by
(7). Metal alloy has been used for the fabrication of this ring.
A cylindrical shaft (8) with one of its end attached to a flat plate (9) is shown
in figure 3. The plate (9) has four circular holes cut through it. This
arrangement can be mounted on a flat surface with the help of fasteners.
The components in figures 1, 2 and 3 are assembled to each other. This
pulley assembly (10) is shown in figure – 4. The circular ring (6) is fitted in
the groove (2) with help of fasteners. The inner grooves (4, 5) of the pulley
are fitted with bearings. The circular shaft (8) is in transition fit with the inner

surface of the bearings. Two more pulley sets (11 & 12) with similar
assemblies are provided.
All the three assembled pulleys (10,11,12) are mounted on a metallic frame
(13) as shown in figure - 5. The plane of the pulleys (10, 12) make an angle
of θ (which is 300) with horizontal plane. The plane of pulley (11) makes an
angle of 900 from horizontal.
The wire rod passes over the first pulley assembly (10) at the beginning and
makes an angle of contact of 1800. The orientation of the second pulley
assembly (11) with respect to the first pulley (10) is chosen such that the
center point of its tension and compression zone is separated by 1200 from
that of the second pulley (11). Similarly the center point of tension and
compression zone of the second pulley (11) is separated by 1200 from that of
the third pulley (12). This has been illustrated in figure - 6. The angle of
contacts made by the wire rod at the second and third pulley (11 and 12) are
also 1800 each.
References
[1] US 5097688 A
[2] US 6000656 A
[3] CN 201989026 U
[4] US 5613286 A
[5] US 4333275 A

WE CLAIM :
1. A mechanical descaler for wire rod drawing to remove oxide layers on
outer surface of hot rolled wire rods, comprising a plurality of pulley
assemblies (10,11,12) mounted on a metallic frame (13), wherein the
plane of the first and third pulley assemblies (10,12) disposed from the
horizontal plane at an angle (9), wherein the second pulley assembly
(11) is at an angle (39) with respect to the horizontal plane, wherein
the wire rods passing over the first pulley assembly (10) at a contact
angle of about 60-2700, wherein the orientation of the second pulley
assembly (11) is selected with respect to the first pulley assembly (10)
such that the center point of the tension and compression zone of the
first pulley assembly (10) is separated by 1200 from the second pulley
assembly (11), and wherein the center point of tension and
compression zone of the second pulley assembly (11) is separated by
1200 from that of the third pulley assembly (12), the contact angle by
the second and third pulley assembly (11,12) with the wire-rod being
1800.
2. The de-scaler as claimed in claim 1, wherein each of the pulley
assemblies (10,11,12) comprises a hollow cylindrical object (1) having
uniformly cut groove (2) at outer curved surface and grooves (3,4,5)
at inner curved surface throughout the periphery;
a circular ring (6) having a profile (7); a cylindrical shaft (8) attached
to a flat plate (9) , wherein each of the pulley assembly is formed by
joining the detachable circular ring (6) in the groove (2) by fastners,
providing bearings on the inner grooves (4,5), and transition fit-up of
the circular shaft (8) with the inner surface of said bearings.

3. The descaler as claimed in claim 2, wherein the component of the
pulley assemblies are made from metal alloy.
4. The descaler as claimed in claim 2, wherein the grooves (4,5) have
identical diameter.