=Paper= {{Paper |id=Vol-2152/p07 |storemode=property |title=Geometric Modeling and Optimized Design of an Hydraulic System for Concrete Batching Plant |pdfUrl=https://ceur-ws.org/Vol-2152/p07.pdf |volume=Vol-2152 |authors=Lucia Cocilovo, Antonio Fichera, Giuseppe Di Lorenzo }} ==Geometric Modeling and Optimized Design of an Hydraulic System for Concrete Batching Plant == https://ceur-ws.org/Vol-2152/p07.pdf

Geometric Modeling and Optimized Design of an
Hydraulic System for Concrete Batching Plant
Lucia Cocilovo1, Antonio Fichera2, Giuseppe Di Lorenzo2
1
Department of Electric, Electronics and Computer Engineering, University of Catania, Catania (Italy)
2
Euromecc S.r.l., Misterbianco (CT)

Abstract - The present paper describes the geometric turned over 180°. The inside height of the open top 40″
modeling and design and the feasibility study of an innovative container is about 2 m. The minimum closed length of the
hydraulic system that would allows a mobile batching plant to telescopic cylinder needs to be of 1 m to suit the container
improve the safety, to increase the reliability and to reduce the transport truck dimension. Assuming a rails inclination of 70°
concrete working process time. In particular, the present paper from the horizontal plane, the stroke of the cylinder must be of
outlines the dynamic behavior of a telescopic hydraulic cylinder 7 m to permit the skip to travel from the bottom to the top
in order to replace the current lift system (skip). Mechanical along the rails. The table below presents the technical features
theory, principles of hydraulics, geometric modelling and design, of a suitable telescopic cylinder:
using cad software, were used in developing the model of the
telescopic cylinder. Using the spreadsheet software Excel it was
possible to compare dynamic movements of some types of
Table. 1. Technical features of telescopic cylinder
actuators. An approach to a hydraulic batching plant lift systems
is presented, where the results are compared with those obtained Technical features Values and units
from the existing skip.
Load capacity 3000 kg
Keywords - Hydraulic cylinder; Batching plant; 3D modeling; Operating pressure 160 [bar]
Reliability; Safety. Stroke speed 34 [m/min]
Stroke length 7000 [mm]
I. INTRODUCTION
Closed length 1000 [mm]
In a mobile batching plant, the skip is a type of loading Open length 7000 [mm]
system that provides the requirement of small dimensions in
the construction site. The skip is a conveyor lift system Load capacity (Retraction) 1000 [kg]
operated by ropes. Given the issues related to: the operation of Mounting configuration Pivot mounts
the lifting device, the reliability of limit switch sensors, the Mounting condition: incline angle 70°
probability of breaking the ropes and other issues involving Environmental condition Dusty
the use of the skip, it was considered essential to investigate
the behaviour of a hydraulic system. Due to the plant’s System operating temperature -10°C < T < +40°C
requirement of small dimensions in the transport
configuration, suitable for container – transport trucks, the
idea is to replace the skip system with a single-acting II. A BRIEF OVERVIEW OF THE HYDRAULIC SYSTEM
telescopic hydraulic system.
The main elements of the hydraulic system are:
1. 3 phase 4 pole asynchronous electric motor (15
kW) 1450 rpm
2. Internal gear pump (160 bar)
3. Pressure gauge and shut-off valve
4. 4/3- way directional control valve
5. Throttle adjustable valve
6. Pressure relief valve (safety valve)
7. Cooler
8. Exhaust filter
9. Intake filter
10. Oil reservoir tank
11. Pipes
Fig. 1. Transport configuration of mobile batching plant. 12. Single- acting telescopic cylinder (4 stages)
The schematically circuit of single-acting telescopic cylinder
In this configuration, the skip rails and the main frame are
is shown in figure 3.
Copyright held by the author(s).

37
When the control valve is moved in the opposite direction,
connecting the chamber of the cylinder with the tank, oil is
forced to pass by the throttle valve (5), that it regulates the
speed of descent. The telescopic cylinder returns to its initial
retracted configuration, thanks to the gravity, because the
hopper discharges the inert into the mixer and it remains only
the empty hopper of 1000 kg of weight.
The pressure relief valve(6) is placed immediately after the
pump. The spring is adjusted to the maximum working
pressure, in such a way that in case of overpressures, the fluid
is discharged into the reservoir tank.
One of the most important components of the hydraulic
drive system is the telescopic hydraulic cylinder, that is an
actuator which gets its power from pressurized hydraulic fluid
(oil, in this case) and it is used to convert fluid power in
mechanical motion. A single-acting cylinder transfers a
hydraulic force in one direction only and it must be retracted
by gravity (in this specific case).

Fig. 2. Operative configuration of mobile batching plant. III. THE TELESCOPIC HYDRAULIC CYLINDER
Telescopic cylinder is a special design of hydraulic
cylinder which provide an exceptionally long output travel
from a very compact retracted length. It consists of nested
multiple cylinders called sleeves, which slide inside each
other.
A telescopic cylinder is used when a long stroke length
and short retracted length are required.
It normally extends from the largest stage to the smallest.

Fig. 4. Functionality of telescopic cylinder.

Fig. 3. Schematically circuit of single-acting telescopic cylinder. This means the largest stage, with all the smaller stages
nested inside it, will move first and complete its stroke before
A pump, driven by an electrical motor, takes oil from that the next stage begins to move. This procedure will
reservoir and the fluid passes through a filter (9), before to continue for each stage until the smallest diameter stage
enter in the circuit. (plunger) will be fully extended. Conversely, when retracting,
When the 4/3 control valve (4) is in its neutral position, the the smallest-diameter stage will retract fully before the next
telescopic cylinder (11) is hydraulically locked and the pump stage starts to move. This continues until all stages are nested
(2) is unloaded back to the tank (10). Oil filters (8-9), situated back in the main. During the initial extension, the cylinder
in the return line to the tank and before the pump, trap solid extends at the slowest speed and with most force. A smaller
particles while allowing fluid to pass trough [1, 2]. diameter stage will extend next, the cylinder extends faster
When the 4/3 way valve is actuated, the discharged line is with less force.
under pressure because the pump must overcome the force of The cylinder load capacity is calculated considering the
load (3000 kg) to be moved [3]. The oil, passing from the 4/3 smallest sleeve diameter in the assembly.
way valve, feeds the ascent of the cylinder. Gravity return type single-acting cylinder is where the
cylinder extends to lift a weight [4] against the force of gravity

38
by applying oil pressure at the blank end. To retract the From the above-mentioned equations it appears clear that
cylinder, the pressure is simply removed from the piston by the parameters of the simplified model refer to the properties
connecting the pressure port to the tank. of rigid body, kinematic and geometric data; moreover, many
of these parameters are changing in time. A consequent
Table. 2. Technical features of telescopic cylinder difficulty in obtaining an accurate valuation derives; the
valuation of the single force component identified by the eq
N° of stages of telescopic 10 9 6 5
(2) was not possible as during the experimental tests the
cylinder stages stages stages stages displacement signal was not recorded. However, it was
Closed length [mm] 910 1000 1550 1528 looking for identifying the static component of the resistance
Open length [mm] 7055 8000 7800 7073 forces by referring to the time intervals where the signals in
pressure were constant or slowly changed. As these intervals
Working max pressure [bar] 200 160 200 200
concerns, a regression of the external force signal was
Stroke length [mm] 6315 7000 6250 5620 fulfilled as experimentally measured with respect to theoretic
Load Capacity [ton] 6.5 - 28 3 34 - 63 10 - 45 signal which was calculated by considering the pressures in
Stroke speed [m/min] 30 30 30 30 the chambers of the cylinder ( ), using different
Amount of oil [l] 149 - 77.5 80
models.
Φ minimum stage [mm] 68 30 80 88 I Modello: ; da cui: ; (3)
Φ maximum stage [mm] 265 220 192 190
II Modello: ; da cui: (4)
Total weight [kg] 391 - 215 253

The first model assumes the presence of a resistance force
IV. NUMERICAL MODEL OF HYDRAULIC CYLINDER as costant and indipendent from the force levels exerted by the
The continuity equation about oil, which after introduction cylinder.
into the cylinder end runs down the opposite site, can be so The second model assumes instead that the resistance
formulated [5]: forces are proportional to the applied force.
The dynamic behaviour of the system was simulated
assuming the theoretic force as input variable and the force
(1)
exerted by the cylinder , experimentally measured, as signal
With: in output. The same problem of a missing recording of the
- i=1, 2, ..., 10 stages displacement signal occured again. Therefore the choice to
realize an empiric model trying to minimize the number of
- , useful thrust surfaces in the cylinder [m2] freedom degrees was taken. After repeated numerical
simulations,it was noticed that a model with a unique pole and
- , opening and closing speed of the extensions zero was the most effective: only with three degrees of
- , volume of fluid entering / leaving the cylinder [m3] freedom (the static benefit and the position of the pole and
zero), it is indeed able to interpolate effectively the
- , pressures in the cylinder inlet / outlet chamber [Pa] experimental data, always provided an index of correlation r2
- Compressing equivalent modulus (thus considering superior to 0.85 Analysis of telescopic cylinder dynamic
the fluid, the air contained in it, etc) movements
Supposing that the oil mass in the hydraulic cylinder can By comparing cylinder features it was selected the 10-
be omitted and act as a rigid body, Newton's second law of stages cylinder to examine in depth its dynamic movements.
motion finds out that:
Table. 3. Stages diameter of 10-stages cylinder
N° of stages Diameter [mm]
(2)
1 68
With: 2 88
- a acceleration of the extensions 3 107

- x extension direction 4 126
5 145
- B coefficiente di smorzamento viscoso [Ns/m]
6 165
- coulomb friction force [N] 7 187
- external force [N] 8 210
9 236
- m equivalent mass of moving parts [kg]
10 265
- force that includes all the resistive forces [N]

39
Table. 4. Areas, volumes and speeds of each stage.
N° of stages Sleeve cross section Sleeve volume Speed sleeve
area [mm2] [mm3] [mm/s]
1 3632 0.002 3590
2 6082 0.004 2144
3 8992 0.006 1450
4 12469 0.008 1046
5 16513 0.011 790 Fig. 6. Space-time chart 10-stage cylinder.
6 21383 0.014 610
From the analysis of the above performance chart the
7 27465 0.019 475 research was focused on finding a more linear extension of the
8 34636 0.024 376 cylinder, reducing the difference between the initial and the
9 43744 0.030 298 final extension speed.
10 55155 0.038 236 The figure 7 was analyzed the space-time chart trend of the
ropes lifting system (skip). The next step was to find a
Total 0.161
cylinder with a similar space-time chart.

An Excel table was created to find relationships between
different variables related to cylinder movements. It was used
to calculate each stage velocities and then the results were
analyzed creating different graphs.
The extension speed shows a slowly increasing trend as a
function of the extension time, while, when the cylinder
extends to the last stage (the plunger- Ø minimum stage), it
reaches the highest speed.

Fig. 7. Space-time chart rope lifting.

Using SolidWorks ver. 2016, it was created a 3D design of
the 10-stages telescopic cylinder, in order to analyze
movements and to check its dimensions such as retracted
length, stroke, etc. The design started by modeling every
single part, then the final 3D assembly model was created.
In Fig. 8 you can see cut view and front view of 10 stage
cylinder. Fig. 9 show axonometric view of 10 stage cylinder in
maximum extension.

Fig. 5. Sleeves Speeds - 10-stages telescopic cylinder.

It was possible to create a chart from the worksheet data to
show the telescopic cylinder performance.

(a) (b)

Fig. 8. (a) 10-stages cylinder; (b) Section view.

40
Table. 5. Diameter and sleeve length of 4- stage cylinder
Numbers of stages Diameter Sleeve length
[mm] [mm]
1 107 1750
2 126 1750
3 145 1750
4 165 1750

Table. 6. Areas, volumes and speeds of four stage
N° of Sleeve Cross Sleeve Volume Sleeve Speed
stages section area [m³] [mm/s]
[mm²]
1 8992 0.015 935
2 12469 0.021 674
3 16513 0.028 509
Fig. 9. Maximum extension10-stages cylinder.
4 21383 0.037 393
Total 0.161
The 3D ball joint model is created using technical design
and data from a company that produces hydraulic cylinders
From the space-time chart it was possible to analyze the
and components. We have chosen this type of interface to
theoretical performance of this 4-stages telescopic cylinder.
reduce the problem of misalignment and transversal force that
Then it was made a comparison graph between the skip and
they can reduce the lifting force and increase the friction
the cylinder space-time charts.
coefficient t [6 - 9].
It was created a design of a 4-stages telescopic cylinder
take into account the effect of friction and functional
Tolerancing [10, 11]. It was found that the latter space-time
cylinder chart is more similar to the linear skip’s chart.

(a) (b)

Fig. 10. (a) Ball joint; (b) Ball joint assembled on last stage.

(a) (b) Fig. 12. Comparison chart between rope lifting and 4-stages cylinder.

Figures below show the design of the 4-stages telescopic
cylinder with some details views.
In order to find the perfect cylinder features to realize a
space-time trend chart as linear as possible, it was chosen a
plunger’s diameter of 107 mm, that can lift up to 3000 kg.

Fig. 11. (a) ball seat; (b) ring, (c) ball.

Using Excel a new space-time chart was obtained
considering a cylinder with a fewer number of stages.

41
V. HYDRAULIC DRIVE SYSTEM LAYOUT
A hydraulic drive system is a drive or transmission system
that uses pressurized hydraulic fluid to power hydraulic
machinery. A hydraulic drive system consists of three parts:
• Power supply section: a hydraulic pump driven by an
electric motor;
(a) (b) • Power control section : valves, filters, piping, etc
using to guide and control the system;
• Drive section : a hydraulic actuator using to drive the
machinery.
This system is used where the telescopic cylinder piston is
returned by the gravity force. With the 4/3-way directional
control valve in neutral position (5), pump flow passes though
the valve and back to the storage/fluid tank (1) also known as
reservoir. The liquid, is generally high density incompressible
oil. It is filtered to remove dust or any other unwanted
particles and then pumped by the hydraulic pump.
The oil filtration unit is also often contained in the power
supply section. Impurities can be introduced into the system as
a result of mechanical wear, too hot or too cold oil or external
environmental influences. For this reason, filters are installed
in the hydraulic circuit to remove dirt particles from the
hydraulic fluid. Water and gases in the oil are also disruptive
(c)
factors and special measures must be taken to remove them.
Fig. 13. (a) Detail of the top; (b) Detail of a cut view of the top;
Valves are devices for controlling the energy flow.
(c) 4-stages telescopic cylinder - fully extended. They can control and regulate the flow direction of the
hydraulic fluid, the pressure, the flow rate and, consequently,
In order to find the perfect cylinder features to realize a the flow velocity.
space-time trend chart as linear as possible, it was chosen a With the 4-stages telescopic cylinder, it is possible to have
plunger’s diameter of 107 mm, that can lift up to 3000 kg. lower speed at the end of the stroke with a minimum stage
Using Excel it was created a comparison space-time chart diameter (d) of 107 mm. The piston surface is:
between two different trends: 4 and 10 stages cylinders. The
next figure shows a comparison chart between the skip and the (5)
other two types of cylinders trends. The cylinder total load capacity is 3000 kg. However to
By comparing the above charts is possible to observe that increase the plant safety an higher weight is considered to
dynamic motions of 4-stages cylinder are better than a 10- select the correct pump. Considering a safety weight of 4000
stages type because the former has a less accentuated speed kg the max operating pressure is:
trend, the line has a reduced slope, and the trend chart is more
similar to the skip’s chart. For the above reasons the 4-stages (6)
cylinder was selected to be fitted in the hydraulic system while
the 10-stage configuration was rejected. Due to the possible oil leakages and other leaks in the
system, system operating pressure is increased up to the safety
value of 60 bar. The stroke time of the telescopic cylinder is
given by the stroke of the cylinder per the cylinder speed (t=
34 m/min):
(7)

The flow rate is:
(8)
Q = 504,53 [l/min].
If the pump couples with an asynchronous 4 pole three-
phase self-braking electric motor operating at 1450 rpm, the
capacity of the pumps is:
Fig. 14. 10 Stage cylinder speed; 4 Stage cylinder speed and Skip speed. (9)

42
The choice of the pump is approached by researching [9] Calì, M., Oliveri, S. M., Sequenzia, G. & Fatuzzo, G.
Companies producing internal hydraulic gear pump, which is (2017). An effective model for the sliding contact forces in
the best option to be fitted in the hydraulic system. a multibody environment. In Advances on Mechanics,
Design Engineering and Manufacturing pp. 675-685.
Springer, Cham.
VI. CONCLUSIONS [10] Capizzi, G., Sciuto, G.L., Napoli, C., Shikler, R. and
In the paper was described geometric optimized design of Woźniak, M. (2018). Optimizing the Organic Solar Cell
an hydraulic system that would allows a mobile batching plant Manufacturing Process by Means of AFM Measurements
to improve the safety, to increase the reliability and to reduce and Neural Networks. Energies, 11(5), pp.1-13.
the concrete working process time. In particular, the present [11] Beritelli, F., Capizzi, G., Sciuto, G.L., Napoli, C. and
paper outlines the dynamic behavior of a telescopic hydraulic Scaglione, F. (2018). Rainfall Estimation Based on the
cylinder in order to replace the current lift system (skip). Intensity of the Received Signal in a LTE/4G Mobile
Due to troubleshooting and maintenance issues regarding Terminal by using a Probabilistic Neural Network. IEEE
the hydraulic system and difficulties in controlling the Access. Online. DOI: 10.1109/ACCESS.2018.2839699 .
cylinder’s retraction speed, a double acting cylinder could be [12] Tran, X. B., Hafizah, N., & Yanada, H. (2012). Modeling
an option to solve technical problems. However, even with the of dynamic friction behaviors of hydraulic cylinders.
application of this device, there is a need of continue Mechatronics, 22(1), pp. 65-75.
maintenance program to make the cylinder operable and safe [13] Calì, M., Oliveri, S.M., Ambu, R. & Fichera, G. (2017).
for a long period of time without dangerous sudden failure An Integrated Approach to Characterize the Dynamic
[12], in particular way for sealing gaskets, subjected to sliding Behaviour of a Mechanical Chain Tensioner by
contact force, infact is extremely important to maintance the Functional Tolerancing. Strojniški vestnik - Journal of
optimal operating tolerance standard [13], and contact with the Mechanical Engineering. pp. 245-257.
metal surface of the extensions and therefore the seal [14].
[14] Yang, M., Shaoping, W. (2011). Failure Diagnosis of
Possible future developments for the present work could
be oriented in researching new applications of telescopic Hydraulic Lifting System Based on Multistage Telescopic
hydraulic systems to be applied in other concrete plants with Cylinder. In Fluid Power and Mechatronics (FPM), 2011
different technical requirements. International Conference IEEE. pp. 828-834.
[15] Calì, M., Zanetti, E. M., Oliveri, S. M., Asero, R.,
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