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 .
• Hydraulic system installed in gasification unit is Open Loop Circuits supplied by
• Hydraulic system in unit-3 is divided into 3 verticals
2.Working field circuit
Hydraulic oil reservoir Main header pump
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
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
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
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
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.
Best operating viscosity range 16 to 43 centistoke.
Require Minimum Cleanliness level ISO 20/18/15
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
• 2 no's accumulator having each capacity 180 L.
• Accumulator fitted with 8 no's (8*75=600 l) of nitrogen cylinder.
• Total 4 no's of line accumulator present at 5 meter & 21 meter
• Each capacity 30 litre .
WORKING FIELD CIRCUIT
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.
• 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.
• 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
• In our circuit only linear type actuators are used with different size.
• Every actuator Fitted with cushioning for avoiding damage of piston seal &
• Maximum speed of actuator is .2m/sec.
• Gasifier area operating actuator hydraulic pressure.
Filtering Unit Cooling unit
• 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.
• 1 no of Screw pump is used for filling purpose having capacity 13l/ min.
• Working pressure 5kg/cm2 & efficiency 93.5%.
• We are using 6 micron duplex filter for recirculation unit .
• > 2 kg/cm2 - warning H
• > 4 kg/cm2 - warning HH
• 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
Daily pm check list
• Leakage from hydraulic hose.
• Looseness of QRC
• Malfunction of solenoid DC valve.
• Increase of hydraulic oil temperature.
• Recirculation pump seal failure.
• Main header pump flow problem.