SES320-1800 Insulating Oil Purifier

Available as a skid or in numerous mobile packages, this completely customizable 1800 GPH conditioning system prepares mineral and Ester-based insulating fluids for service.

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This compact, mobile insulating oil conditioning system is designed for single pass conditioning of new and in-service (Group I & II) insulating fluids, increasing voltage values (dielectric strength) by removing dissolved water, dissolved gas, and solid matter contamination. The SES320-1800 includes vacuum dry out capabilities and can be used to vacuum filling. 

SES320-1800 Highlights

30 GPM/6840 LPM

160 kW Electric Heating (Std)

1200 Cfm Vacuum System (Std)

6.5 PSI Inlet NPSH

70 PSI Discharge Pressure


More Specifications

SES320 1800 1000X1000


Mineral OilNatural Ester Fluids

Processing Rate

1800 GPH
6840 LPH

De-rate processing rate and heating capacity by 25%

Dielectric Strength
(ASTM-D1816-84A 1 mm gap)

>65 KVA

>60 KVA

Moisture Content

100 ppm reduced to < 10 ppm
50 ppm reduced to < 5 ppm

100 ppm reduced to < 25 ppm

Total Gas Content

12% reduced to < 0.25%
10% reduced to 0.15%

10% reduced to < 0.25%

Particulate Content

99.9% > 1 micron
97.8% > 1/2 micron

99.8% > 1 micron

Processing Temperature

Min 120F° / 49C°
Max Limit 190F° / 88C°

Min 160F° / 71C°
Max Limit 190F° / 88C°

Processing Vacuum Level    

1.5 torr – 0.3 torr

1.0 torr – 0.1 torr


Typically built to order, the SES320-1800 and can be customized to any requirement 

Standard Flow Circuit

  • Automatic internal recirculation – no valves to adjust
  • Automation degas chamber level control
  • Discharge pressure is automatically controlled and adjustable to 70 psi
  • Discharge adjustable from 0 – 100% of circulation rate
  • Built-in hose suck back and drain capability

Oil Pumping System

  • Two pump systems. (Inlet pump standard
  • Direct mount low-speed positive displacement screw pumps
  • Viton mechanical seals
  • External relief valves

Electric Heating Systems

  • Low watt density heating does not degrade oil
  • 32 Kw heater banks
  • Heater banks can be disabled at the control panel to reduce amperage requirement if necessary
  • Digital PID individual bank control scheme provides smooth accurate generator friendly operation
  • Oil flow and over temperature safety interlocks provided

Filtration System

  • Coarse inlet pump strainer provided
  • Dual ASME code filter housings provide two-stage particulate filtration. 3 & 0.5 micron
  • High efficiency pleated synthetic filter media
  • 99.8% efficiency
  • Local dirty filter gauges standard
  • Automatic air bleed standard

Degasification System

  • Three stage dispersal system
  • Single-pass performance
  • 316 Stainless Steel chamber shell and interior components
  • Automatic non-pilot operated level control system
  • Primary dispersing system
  • Transparent chamber cover on system 
  • Safety high-level overflow shutdown interlock switch
  • Low-level warning switch
  • Fiber optic foam control system
  • Automatic vent

Vacuum System

  • Two-stage system
  • System capacity is sized at 0.5 torr for 1.25X the maximum oil conditioning vapor load.
  • Vacuum system blank off pressure is < 0.05 torr
  • Vacuum systems can be isolated for dedicated transformer evacuation
  • 304 stainless steel vacuum system piping
  • Vacuum booster pump inlet safety oil trap w/ shutdown interlock is provided. Protects vacuum booster pump from the chamber or transformer overflow
  • Rotary piston or rotary screw vane backing vacuum pump
  • Direct drive Roots-style rotary lobe pump vacuum booster pump

Local Instrumentation 

  • Inlet Suction Gauge
  • Inlet Temperature Gauge
  • Filter Inlet & Outlet Gauges
  • Dirty Filter Gauges
  • Chamber Manifold Vacuum Gauge
  • Discharge Pressure Gauge
  • Discharge Temperature Gauge
  • Flow Rate Meter
  • Dual Register Positive Displacement Flow Totaling Meter

Electrical System

  • All control packages are built to NEMA and IEC specifications
  • Main Power Disconnect Breaker
  • 100% Circuit Breaker Protection
  • IEC Motor Starters and Overload Protection
  • Circuit Breaker Protected Heater Contactors
  • Individually Controlled Banked Heaters
  • System Hour Meter
  • Vacuum Pump Hour Meter
  • Alarm Horn
  • Amp Meter
  • Phase Indicator

Standard Control System

  • The PLC controlled system uses a NEMA 4, 15” color touchscreen operator interface to graphically illustrate the system flow path and provide oil & vacuum pump, heating system, and automatic valve control. Pumps, heaters, and automatic valves status are indicated graphically. The system annunciates alarms visually and audibly. Additional screen pages are provided for maintenance, troubleshooting, alarm logging and data logging. Remote monitoring is optional.
  • Traditional switch and pilot light interfaces and relay logic are optional 


Control System Information:

  • HMI Status & Control Displays:
    • All Motors
    • All Heater Banks
    • All Actuated Valve Positions
    • All Alarms
    • All Warnings
    • Oil Temperature Set Point
  • HMI Displayed Instrumentation:
    • Inlet Pressure
    • Outlet Oil Flow Rate
    • Outlet Out Total Gallons
    • Outlet Pressure
    • Degas Chamber Vacuum Level
    • External Vacuum Line Vacuum Level
    • Heater Outlet Temperature


  • Skid mounted with a recessed deck plate for drip collection.
  • System design facilitates easy access for maintenance and operation.
  • Piping
    • All oil piping is welded carbon steel w/ butt weld or socket fittings. All vapor and water piping is stainless steel with w/ but weld or socket weld fittings. Maintenance connections use bolted flanges or O-ring sealed unions. Threaded unions are not used. Threaded connections are kept to a minimum.
  • Instrumentation Tubing
    • Oil filled tubing is 1/4" carbon steel w/ carbon steel compression fittings.
  • Electrical Conduit
    • A combination of ridged and liquid-tight flexible conduit is used to provide a watertight easy maintenance wiring system

 Flow Circuit

  • Variable speed circulation rate on the 600, 900, and 1200 sizes
  • Higher discharge pressures are available

Oil Pumping System

  • Inlet oil booster pump for evacuated transformer circulation

Electric Heating System

  • Discharge heating system for post degas temperature boost. 
  • Oil Fired Heating Systems
    • Duel zone scheme provides discharge heating capabilities

Filtration System

  • Dirty filter alarms
  • Oversized inlet housing
  • Filter housing isolation valves and bypass piping 

Degasification System

  • Level transmitter for control system display

Vacuum System

  • Internal bypass booster pumps are available on 1800, 2400, and 3000 GPH systems
  • Redundant backing pumps are available on 1200, 1800, 2400 and 3000 GPH System
  • Redundant vacuum systems are available on 1200, 1800, 2400 and 3000 GPH System
  • Inter-stage refrigerated condensing systems for piston and vane backing pumps.
  • Fail closed external vacuum line actuated valves
  • Actuated vacuum system valves for automatic control panel configuration
  • Vacuum line evacuation cold traps with automatic defrost
  • Transformer vacuum and hot oil spray manifolds


  • Remote Digital Transformer Vacuum Gauge (760 torr – 0.01 torr
  • Inlet Moisture & Temperature monitor  
  • Outlet Moisture & Temperature Monitor
  • External Vacuum Line Dew Point Monitor 
  • Discharge Oil ISO Cleanliness Monitor 
  • Discharge Oil Total Gas Content Monitor

Control & Electrical System Options

  • HMI Displayed Instrumentation:
    • Inlet Temperature
    • Inlet Moisture (ppm)
    • Outlet Temperature
    • Outlet Moisture Content (ppm)
    • Degas Chamber Oil Level
    • Remote Transformer Vacuum Level
    • Vacuum Line Dew Point
    • System Amp Draw
    • Oil Storage Tank Level
    • Discharge Total Gas Content
    • ISO Cleanliness Classification
  • Switch & Pilot Light Control Package
    • Relay logic 
    • Illuminated LED Process Status Schematic
    • Pilot lights are provided for alarm condition indication
  • Data logging
  • Remote Monitoring for  IOS, Android, and Browser devices
    • Remote troubleshooting and logic updates  

Integrated Oil Storage

Process integrated onboard oil storage can be provided. Typically used for transformer top off, extra fill oil storage, Earthwork make up oil.

  • Standard sizes are 150 & 225 gallons
  • 304 SS construction.
  • Interconnecting piping permits inboard oil processing through the storage tank
  • Standard Equipment:
    • Inlet & discharge valves
    • Safety high-level switch with control system interlock
    • External level gauge
    • Drain valve
  • Optional actuated supply and return valves for HMI processing mode configuration

Fullers Earth Treatment Options

The SES320 conditioning system can be designed to accommodate a standalone Fullers Earth treatment skid. When used together, the combined process can be used to regenerate in-service oils group III oils.  The Fullers Earth adsorbent process is used to reduce Total Acid Number (TAN) values, remove oxidation by-products, and degraded oil sludge, and restore color values.  For permanently installed Earth treatment see the SES320R reclamation system.

  • Optional provisions to accommodate a standalone Fullers Earth treatment skid provides the following:
    • Earth system supply and return connections down steam of the inlet heating system
    • Inlet pumping system design changes to accommodate the earth system oil pressure requirements.
    • Variable speed circulation rate is provided to optimize the earth system contact time.
  • Optional inhibitor mixing and injection system
    • Used to restore oil oxidation inhibitor additive removed by the Earth system process.

Hose Storage Options for Mobile Applications

  • Skid integrated horizontal easy access hose storage assembly
    • Stores up to (5) 4” x 20’ straight vacuum hose assemblies
    • Stores up to (8) 2” x 20’ straight oil hose assemblies
  • Vertical hose storage assembly
    • Stores up to (4) 4” x 15’ straight vacuum hose assemblies
    • Stores up to (8) 2” x 15’ straight oil hose assemblies
  • Live hose reels with low-speed electric or crank rewind
  • Storage only hose reels with low-speed electric or crank rewind

The SES320-1800 has numerous mounting options 


  • Straight Truck Mounting
    All straight truck chassis and bodies are custom ordered to accommodate the equipment option package, maximum terrain, load, weight distribution and towing requirements. Maximum straight truck box length is 28FT.  
  • Skid Mounting
    Built-to-order skid-mounted equipment can normally be built to meet customer footprint and access requirements.  Consult SESCO with special requests.
  • Enclosed Deck over Axle Cargo Trailer Mounting
    Unlike a standard cargo trailer, the equipment deck on a “deckover” cargo trailer rides above the axle assembly and incorporates a leaf spring or air bag suspension. The “deckover” design accommodates wider, longer, and heavier equipment payloads. All “deckover” cargo trailers are specifically engineered to accommodate equipment load and weight distribution to provide optimum towing conditions. Weight capacities (GVRW) range from 20,000 to 30,000 Lbs. SESCO will provide the trailer size and weight capacity options available for the system being quoted.
  • Dry Van Trailer Mounting
    The size and weight capacities of a dry van trailer accommodate a wide variety of options and equipment accessories.  Dry van trailer packages are specifically engineered to accommodate equipment loading axle weight distribution regulations.