1.
HYDRAULIC SYSTEM
Hydraulic system:
A industrial hydraulic system is fluid circuit based on hydrostatic principle that uses
pressurized hydraulic fluid to power hydraulic machinery.
There are 2 types of hydraulic circuits used in fluid power applications.
Open Loop Circuits:
These are circuits where the inlet of hydraulic pump and the actuator(or valve)
return are connected to a hydraulic reservoir.
Closed Loop Circuits:
These are circuits where the motor return is connected directly to the hydraulic
pump inlet .

2.
• Hydraulic system installed in gasification unit is Open Loop Circuits supplied by
M/s Rexroth.
• Hydraulic system in unit-3 is divided into 3 verticals
1.Power pack
2.Working field circuit
3.Recirculation unit

3.
Hydraulic oil reservoir Main header pump
Discharge filter
& NRV
Field
working
circuit
Main header
accumulator
Line
accumulator
filter
Bearing
flushing line
Return
line PSV
Power pack
Drain
line

4.
Hydraulic reservoir
 Tank capacity-6000 lit
 Material- Stainless steel with tank inside Epoxy coated.
 Design for atmospheric pressure & temp 20-70o c
 Reservoir divide with main pump suction chamber & Return line
chamber.
 Oil chambers are provided by 4o slope from centre to out word for
easy removal of dirt particle.
 Reservoir Fitted with two breather for filtration & dehumidification of
intake air.

5.
 Reservoir maximum & minimum oil level
>68%– warning HH
>65%– warning H
> 33%– warning L
>24%– warning LL
 Reservoir maximum & minimum oil Temperature
>62oc– warning HH
>60oc – warning H

6.
HYDRAULIC OIL
 HFDR-46 synthetic oil is used in our hydraulic system.
Properties of HFDR-46
 Fire resistant hydraulic fluid based on selected phosphate esters
Good lubrication performance and anti-wear properties.
Excellent oxidation stability.
Prevention of foaming and very quick air release

7.
Main Hydraulic pump
• 4 no's of Multiaxial piston pump installed considering 3 no's pump
in continuous operation & 1 pump for standby condition.
 Type-A4VSO180 Variable displacement type pump.
 Capacity-223 l/m
 discharge pressure-110kg/cm2,
 Efficiency-93.5%
 Best operating viscosity range 16 to 43 centistoke.
Require Minimum Cleanliness level ISO 20/18/15

8.
NAS & ISO 4406 interconversion
Maximum Contamination Limits (per 100 mL)
Size range in microns
Approximate
ISO 4406
Equivalent
NAS 1638
code
5-15 µm 15-25 µm 25-50 µm 50-100 µm Over 100 µm
— 00 125 22 4 1 0
— 0 250 44 8 2 0
12/10/7 1 500 89 16 3 1
13/11/8 2 1000 178 32 6 1
14/12/9 3 2000 356 63 11 2
15/13/10 4 4000 712 126 22 4
16/14/11 5 8000 1425 253 45 8
17/15/12 6 16,000 2850 506 90 16
18/16/13 7 32,000 5700 1012 190 32
19/17/14 8 64,000 11,400 2025 360 64
20/18/15 9 128,000 22,800 4050 720 128
21/19/16 10 256,000 45,600 8100 1440 256
22/20/17 11 512,000 91,200 16,200 2880 512
23/21/18 12 1,024,000 182,400 32,400 5760 1020

9.
DICHARGE & RETURN LINE FILTER
• General: Filter clogging indicators to be evaluated only when fluid
temperature is higher than 30o C.
• Each discharge line of main pump Fitted with 10 micron filter.
> 5 kg/cm2 – warning H
> 7 kg/cm2 - warning HH
• Return line fitted with 10 micron filter.
> 2 kg/cm2 - warning H
> 4 kg/cm2 - warning HH

10.
ACCUMULATOR SECTION
Main accumulator
• 2 no's accumulator having each capacity 180 L.
• Accumulator fitted with 8 no's (8*75=600 l) of nitrogen cylinder.
Line Accumulator
• Total 4 no's of line accumulator present at 5 meter & 21 meter
• Each capacity 30 litre .

11.
WORKING FIELD CIRCUIT
Pressure
reducing
valve
solenoid DC
Valve
Flow control
Circuit
selection
Actuator
Mimic panel
accumulator Pressure
reducing
valve
Optional Valve

12.
PRESSURE REDUCING VALVE
• 2 pressure reducing valve in parallel connection (Size-NG20)
• General pressure setting 65kg/cm2 & 67kg/cm2
• Extra pressure reducing valve for dv6,dv2,dv4 & ash lock bottom cone.
• General pressure setting for reducing valve is 30kg/cm2.
SOLENOID OPERATED DC VALVE
• we are using 4/2 or 4/3 DC solenoid valve with hydraulic pilot line operated.
• Always we have extra solenoid DC valve for avoiding any malpractice situation.
FLOW CONTROL
• Meter in type flow control are installed in our hydraulic circuit.
• Main purpose of this meter in type circuit is velocity control in our actuator.

13.
CIRCUIT SELECTION
• Each circuit has 2 no's of solenoid operated DC valve.
• Out of which we can choose running & isolation of any DC valve by manual ball
valve.
ACTUATER
• In our circuit only linear type actuators are used with different size.
• Every actuator Fitted with cushioning for avoiding damage of piston seal &
equipment.
• Maximum speed of actuator is .2m/sec.
• Gasifier area operating actuator hydraulic pressure.

14.
Sl no Equipment actuator name Operating pressure
1 Coal feeding chute 65kg/cm2
2 Coal lock top cone 30kg/cm2
3 Coal lock bottom cone 65kg/cm2
4 Ash lock top cone 65kg/cm2
5 Ash lock bottom cone 30kg/cm2
6 DV1 valve 65kg/cm2
7 DV2 valve 30kg/cm2
8 DV5 valve 65kg/cm2
9 DV6 valve 30kg/cm2
10 PV1 valve 65kg/cm2

15.
RECIRCULATION PART
Hydraulic oil
Reservoir
Recirculation
pump
Filtering Unit Cooling unit
Main pump
bearing
flushing line
Temp sense
bypass line
Filling
pump
NRV

16.
RECIRCULATION PUMP
• 2no’s of Screw pump(1 running & 1 standby) are used for cooling purpose having
capacity 110 l/min.
• Working pressure 10kg/cm2 & efficiency 93.5%.
• Self priming type screw pump with triple screw.
FILLING PUMP
• 1 no of Screw pump is used for filling purpose having capacity 13l/ min.
• Working pressure 5kg/cm2 & efficiency 93.5%.
FILTERING UNIT
• We are using 6 micron duplex filter for recirculation unit .
• > 2 kg/cm2 - warning H
• > 4 kg/cm2 - warning HH

17.
COOLING UNIT
• We are using shell & tube type Heat exchanger for cooling purpose
with 1 stand by condition.
• Cooling water flow 100 lit/min at maximum 35ocentigrade.
• Cooling water inlet to the heat exchanger control by thermostatically
reservoir temperature.
Daily pm check list

18.
FREQUENT PRBLEMS
• Leakage from hydraulic hose.
• Looseness of QRC
• Malfunction of solenoid DC valve.
• Increase of hydraulic oil temperature.
MAJOR FAILURE
• Recirculation pump seal failure.
• Main header pump flow problem.

19.
THANKS