JOURNAL OF FOOD SCIENCE
VOLUME 2 APRIL 2023 ISSN: 2181-385X
119
`
NEW DESIGN OF INTER-SAW GASKET FOR FIBER-SEPARATING
MACHINES
Ibragimov Farxod Xayrulloyevich
Toshkent kimyo texnologiya institutiti, kafedra mudiri
E-mail: Farkhod.Ibragimov.1985@mail.ru
Muhammadiyev D.M
Abstract.
The article presents data on the substantiation of a new design of gaskets for saw gins,
characterized by a lightweight type and a composite structure of individual steel elements (disk with
splines, rim), welded after preliminary assembly.
The steel structure of the inter-saw gasket, as shown by experimental studies on axial
compression, in contrast to aluminum design, is characterized by high strength, less permanent
deformation, increased hardness and the ability to maintain performance for a long time under repeated
operation without violating the technological conditions of ginning.
Keywords
:
fiber-separating machines, saw gin, saw cylinder, inter-saw gasket, saw blade,
straight-sided spline, belt, axial compression, stress, deformation, deformation diagram.
НОВАЯ КОНСТРУКSИЯ МЕЖПИЛЬНОЙ ПРОКЛАДКИ ДЛЯ
ВОЛКОРАЗДЕЛИТЕЛЬНЫХ МАШИН
Аннотация
.
В статье приведены данные по обоснованию новой конструкции
прокладок для пильных станков, характеризующихся облегченным типом и составной
конструкцией из отдельных стальных элементов (диск со шлиsами, обод), свариваемых после
предварительной сборки.
Стальная конструкция межпильной прокладки, как показали экспериментальные
исследования на осевое сжатие, в отличие от алюминиевой конструкsии, характеризуется
повышенной прочностью, меньшей остаточной деформацией, повышенной твердостью и
способностью сохранят работоспособност длительное время при многократной эксплуатации.
без нарушения технологических условий джинирования.
Ключевые слова
:
волокноразделительные машины, пильный станок, пильный цилиндр,
межпильная прокладка, пильный диск, прямосторонний шлиц, ремень, осевое сжатие,
напряжение, деформация, диаграмма деформации.
JOURNAL OF FOOD SCIENCE
VOLUME 2 APRIL 2023 ISSN: 2181-385X
120
`
INTRODUCTION.
The main machine for separating fibers in cotton processing is a saw gin, which consists of a
working div in the form of a saw cylinder (Fig. 1). The saw cylinder includes the most massive and
critical parts - saw blades and inter-saw gaskets. The latter have a diameter of 160 mm and are
designed to increase the hardness of the saws on the working shaft under assembly and operating
loads.
Fig. 1. Saw cylinder of 4DP-130 gin:
1 - washer; 2 –inter-saw gasket; 3 - saw blade; 4 - nut; 5 - shaft
The inter-saw gaskets located between the saws set a predetermined distance between them equal
to 17.05 mm. Taking into account the fact that the axial runout of the saws during rotation as part of the
saw cylinder should be no more than 0.2 mm [1] and strictly pass through the center of the slotted gap
between the grates, increased requirements are imposed on the thickness of the end support surfaces to
the accuracy of the manufacture of inter-saw gaskets.This is due to the fact that when the position of the
saw blades in the slotted gap between the grates is changed due to unacceptable axial runout of the saws
or large elastoplastic deformations of the inter-saw gaskets, the fibers torn off from the seeds and pulled
by the saw teeth through the working surfaces of the grates are damaged.
The use of aluminum alloy for the manufacture of inter-saw gaskets is justified by the fact that
their total weight is included in the dependence for calculating a uniformly distributed load
q
on the
working shaft of the saw cylinder between the supports:
0
l
G
G
G
q
wsg
wsaw
ws
N/mm
(1)
where
ws
G
is the weight of the shaft between the supports, N;
JOURNAL OF FOOD SCIENCE
VOLUME 2 APRIL 2023 ISSN: 2181-385X
121
`
wsaw
G
is the weight of the saw, N;
wsg
G
is the weight of inter-sawgaskets, N;
o
L
is the distance between supports, mm.
The reduction in the weight of the inter-saw gaskets (the number of which depends on the design
of a saw gin and can be 89 or 129), becomes an important factor to ensure sufficient strength, hardness,
and vibration resistance of the working div of the machine. In case of violation of the listed
performance criteria of the saw cylinder parts, the ginning process deteriorates and the quality of fiber
decreases due to their damage.
Silumin [2] is an aluminum alloy with a high silicon content, high casting, technological and
mechanical properties; it is used for the manufacture of inter-saw gaskets. The use for this purpose of
AL9 alloy (special, hypoeutectic silumin with 4 ... 10% Si with the addition of copper, magnesium and
manganese) is caused by its relatively high mechanical properties, which distinguishes it, for example,
from AL2 alloy, when high mechanical strength is not requiredfor castings the elements of complex
shape (Table) [3].
Table
Chemical composition (%) of cast aluminum alloys
Alloy grade
Basic components
Impurities (no more than)
Mg
Si
Mn
Cu
Fe
imp
AL9
0.2-0.4
6.0-8.0
-
-
0.3-1.0
1.0-1.9
AL2
-
10-13
-
-
0.8-1.5
2.2-2.8
Aluminum alloy AL9 refers to heat-treated cast alloys based on silumin AL2 with additions of
Mg and Cu for other alloys. After heat treatment (quenching at
С
0
530
520
in hot water
(
С
0
100
50
), followed by hardening tempering at
С
0
180
50
for 10-30 hours), mechanical properties
are: tensile strength
200
в
MPa
, yield strength
110
Т
MPa
, percentage elongation
%
6
, hardness
HB75, density
68
,
2
3
/
сm
g
.
Duralumin of common composition is used when higher mechanical properties and good
plasticity are required in the hot state, (when using duralumin in forged or stamped form, it is designated
as AK1); other alloys close in composition to duralumin (AK6, AK8) are also used. Mechanical
properties of AK alloys are characterized by tensile strength
460
......
280
в
MPa
and percentage
elongation
%
10
....
7
[3].
JOURNAL OF FOOD SCIENCE
VOLUME 2 APRIL 2023 ISSN: 2181-385X
122
`
METHODS.
Compared with cast aluminum alloys (see table), the strength of AK alloys is 2 times higher and
the percentage elongation is also higher. Given this circumstance, a number of critical parts from
aluminum alloys are made by forging (pistons, impellers, blades, axial compressor disks of turbojet
engines, etc.). These alloys are characterized by a constant creep rate for a long time and a low velocity
of fatigue cracks propagation in parts with stress concentrators.
Thus, the use of forged aluminum alloys is more preferable to casting alloys since they have
higher mechanical properties and greater resistance to the action of repeated fluctuating stresses
characteristic of the operation of the saw cylinder in cotton-ginning machines.
Under the action of the axial force of the saw tightening
o
F
(not less than 2
10
5
N) [4], aluminum
inter-saw gaskets are prone to plastic deformations leading to irreversible changes in the linear
dimensions (thickness of the gaskets), which is an obstacle to their repeated use. A decrease in the
thickness of the inter-saw gaskets inevitably leads to a decrease in the required distance between the
saws, which can cause the side surfaces of the saw teeth to touch the cast iron grates and, to catastrophic
wear of the teeth, as well as to a very dangerous phenomenon - sparking.
The impossibility of repeated use of aluminum inter-saw gaskets is explained by the fact that
with repeated plastic deformations that occur when the saw cylinder is tightened with restored saws after
the teeth crossing to a new size, re-hardening i.e. exhaustion of plastic properties margin of the material
may occur. Cracks may appear, leading to the destruction of a partdue to the increased brittleness in the
surface layer of the gaskets under the action of axial compressive load. Thus, the creation of an effective
design of gaskets for fiber-separating machines is of particular relevance and requires a strictly
scientifically grounded approach when choosing the material and the method for calculating the stress-
strain state, taking into account various schemes for approximating the loading diagram.
JOURNAL OF FOOD SCIENCE
VOLUME 2 APRIL 2023 ISSN: 2181-385X
123
`
Fig. 2. Composite construction of the gin steel inter-saw gasket:
1 – disk; 2– shaft holes; 3 - belt; 4-straight-sided spline; 5 - spline holes.
MATERIALS.
The inter-saw gasket (Fig. 2) contains a disk 1 with a hole 2 for theshaft size and with a
concentrically located belt 3, which determines the thickness of the inter-saw gasket. On the outer
surface of disk 1 with a diameter D (Fig. 3), straight-sided splines 2 are provided, which serve to fix and
connect with a concentrically located belt 4 using holes 5 with an appropriate pitch.
Assembly of a composite structure of a steel inter-saw gasket is carried out by the following
technological operations:
- rolling the belt 4 to form a ring with a diameter D;
- installation of straight-sided splines 2 ofdisk 1 inside holes 5 over the entire surface of belt 4;
- weldingdisk 1 and belt 4, ensuring diameter D.
Fig. 3. Elements of the inter-saw gasket:
1– disk; 2 - straight-sided splines; 3 - shaft hole; 4 - belt; 5 - holes for straight-sided splines
Full-scale compression tests of gaskets made of aluminum alloy (currently used in cotton
factories), and of the proposed composite structures made of carbon steel St3 were conducted. The
choice of the limit values of compressive load is related to the beginning of the material destruction for
aluminum gaskets and the loss of structural hardness, leading to a violation of the original shape of the
steel inter-saw gaskets.
RESULTS AND DISCUSSION.
Experimental studies on uniaxial compression were conducted on a PMM-125 test press, which
has a hydraulic drive for lifting the plunger during the operating stroke and creating the required force
on the test sample. The range of forces generated by the press corresponds to the values
tf
P
20
0
,
JOURNAL OF FOOD SCIENCE
VOLUME 2 APRIL 2023 ISSN: 2181-385X
124
`
tf
50
0
and
tf
125
0
The press design during testing of samples makes it possible to record the
deformation-force dependence on special paper using a diagram apparatus on the control panel of the
press. A measuring complex with additional sensors and fixtures was used to study the loading-
unloading process and deformation components. To increase the accuracy and expand the measurement
area, the measuring complex was improved using computer technology in the PMM-125 test press
system.
A special program allows registering the absolute deformation of the sample in
mm
and the
compressive force in on a computer monitor in real-time of the experiment. After reaching the maximum
value of compressive force max
P
, the specimen destruction begins, followed by a load drop (Figs. 4 and
5). Fracture of the gasket is characterized by delamination, separation of fibers and fracturing; transverse
folds and cracks are formed on the lateral surface of a sample.
The duration of the tests, reflected horizontally, can be set from a few minutes to one hour.
Analysis of the results of experimental studies, presented in the form of a loading-unloading
diagram, showed the following. The greatest compressive force for steel inter-saw gaskets is more than
2 times higher than that for gaskets made of AK5M2 aluminum alloy. A characteristic feature of the
AK5M2 alloy is that at the time of unloading, an increase in the absolute deformation continues (Fig. 4)
due to higher plasticity than the plasticity of a steel sample. A different patternis observed in the loading-
unloading diagram of steel gaskets. Due to the high modulus of elasticity and lower plasticity, the change
in the absolute deformation
l
of the sample is an instantaneous response to the drop in the load and it
literally copies the pattern of load change during unloading (Fig. 6).
Loading-unloading diagrams make it possible to estimate the total absolute deformation
pll
l
corresponding to the destruction of samples and to distinguish in it elastic
у
l
and plastic (residual)
pll
l
deformation:
п
l
у
l
+
пл
l
(2)
In expression (2), total deformation
tot
l
can be considered as destructive deformation
des
l
under the given conditions of deformation in the process of axial compression of the samples under
consideration. If the absolute plastic deformation
pll
l
for steel samples is
%
20
of total
pll
l
then for
samples made of aluminum alloy it is more than
%
40
, which may negatively affect the performance of
the inter-saw gaskets under operating conditions due to significant irreversible changes in the thickness
of the gaskets and disturbances in the normal operation of the saw cylinder of gins and linters.
JOURNAL OF FOOD SCIENCE
VOLUME 2 APRIL 2023 ISSN: 2181-385X
125
`
Taking into account the area of the bearing (contact) surface of the inter-saw gaskets and the
destructive loads max
P
, it is possible to calculatefrom the loading diagram the corresponding normal
stresses max
leading to the sample destruction
A
P
/
max
max
(3)
where
2
4
,
10
12
m
A
- is the area of the bearing surface of a serial gasket made of aluminum alloy;
2
4
,
10
5
m
A
is the area of the supporting surface of the proposed composite structure made of steel
St3.
For steel gaskets:
;
196200
20
max
N
тс
P
2
max
/
4
.
392
mm
N
Foraluminumgaskets:
N
тс
P
107910
11
max
2
max
/
9
.
89
mm
N
Relative residual deformation
res
, calculated considering the thickness of the inter-saw gaskets
mm
h
05
.
17
, showed its significant difference (by more than 3 times):
035
.
0
05
.
17
6
.
0
h
l
пл
ост
(steel gaskets),
111
.
0
05
.
17
9
.
1
h
l
пл
ост
(aluminum gaskets),
Fig. 4. Deformation diagram under axial compression of aluminum gaskets during loading-
unloading
JOURNAL OF FOOD SCIENCE
VOLUME 2 APRIL 2023 ISSN: 2181-385X
126
`
Fig. 5. Deformation diagram under axial compression of steel gaskets during loading-unloading
Thus, as evidenced by full-scale tests for axial compression of inter-saw gaskets, the new
composite structure of the steel gasket undergoes permanent deformation, much less than the
deformation of aluminum gaskets. Therefore, steel gaskets of lightweight design are able to resist
deformation for a long time, maintaining the specified thickness of the gasket. This fact has a positive
effect on the ginning and linting processes since it prevents catastrophic wear of the operating surfaces
of the saw blade teeth at sudden touch with the cast iron grates due to the violation of the regulated gap
between the disks and grates in the operating area of machine.
It should be taken into account that the inter-saw gaskets, being in a stress-strain state as a result
of axial compression during the assembly of the saw cylinder, are subjected to additional torsional
deformation (elastic or plastic ones depending on the load - torque) under operating conditions.
Consequently, the belt of the steel inter-saw gasket, considered as a thin-walled tubular rod, is in a
complex stress-strain state (compression and torsion of a thin-walled pipe). The stress state of a pipe can
be considered homogeneous with nonzero stress components: normal stress
z
and shear stress
z
. On
JOURNAL OF FOOD SCIENCE
VOLUME 2 APRIL 2023 ISSN: 2181-385X
127
`
the basis of the deformation theory of plasticity [7], it is possible to determine these stresses that satisfy
the yield condition
1
2
2
(4)
Where
T
z
/
and
T
z
/
;
T
and
T
are the tensile (compression) and shear yield
points, respectively.
To determine
and
(4), it is enough to know the relative linear
and angular deformations
at a given time of deformation.
The importance of calculating structural elements in the plastic area is justified by the fact that
when the reserve of plasticity is exhausted, destructive processes begin, usually from the surface of the
parts, where the greatest stresses act. In theoretical studies and in practical cases, it is necessary to know
the load under which plastic deformations first appear. The stresses at a given point of the div should
satisfy the plasticity condition [8-9].
Thus, a new design of an inter-saw gasket for fiber-separating machines of the cotton industry
was proposed and substantiated. This design of a gasket is a composite structure with low weight; it
differs in material (St3). The new steel inter-saw gasket, in contrast to the aluminum one, is designed for
multiple uses due to its lower deformability and increased dimensional stability. Production tests have
shown that gins equipped with new steel gaskets provide higher fiber quality and equipment reliability.
JOURNAL OF FOOD SCIENCE
VOLUME 2 APRIL 2023 ISSN: 2181-385X
128
`
REFERENCES
1.
Primary processing of raw cotton / Ed. by E.Z. Zikrieva. - Tashkent: Mekhnat, 1999. –
400 p.
2.
Khamov M.G. Repair, installation and adjustment of cotton-ginning equipment. -
Tashkent. Ukituvchi, 1990.-536 p.
3.
Gulyaev A.P. Metallurgy.-M: Metallurgy, 1986.-544 p.
4.
Miroshichenko G.I. Fundamentals of designing machines for primary processing of
cotton.-M.: Mashinostroenie, 1972. -231 p.
5.
Patent of the RUz. FAP 01182 No. 2 2017, Gasket for cotton ginning machines /.
Mukhammadiev D.M., Ibragimov F.Kh., Akhmedov Kh.A., Primov B. Kh., Mukhammadiev T.D. //
Rasmiy Ahborothnoma -2017.-№-2
6.
IbragimovF.Kh. Development and substantiation of the parameters of a new design of
inter-saw gaskets for cotton-ginning machines: Abstract of the dissertation, Doctor of Philosophy (in
technical sciences) .- Tashkent: TITLP, 2019. – 38p.
7.
Filin A.P. Applied Mechanics of Deformable Rigid Body. In 3 volumes. M: Nauka, 1975.
–V.1-832 p.
8.
F.Kh.Ibragimov, N.B.Mirzayev, O.A.Ortiqov, T.A.Pulatov, A.A.Khamitov and Kh.A.
Akhmedov. Dynamics of plane motion of a rigid div. Turkish Journal of Computer and Mathematics
Education Vol.12 No.7 (2021),1107-1111
https:// journals. tubitak. gov.tr /physics/ index.htm
9.
Mukhammadiev D.M., Ibragimov F.Kh., Mukhammadiev T.D. mathematical simulation
of the movement of a machine unit of a saw cylinder with distributed parameters.
problems of machine
building and reliability of machines 2020, no. 3, p. 94-101
