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MO Series Oil Coolers for Turbines
Shell-and-tube MO series oil coolers — MO-05, MO-2, MO-2.5, MO-4, MO-10 and MO-20 — for steam turbine lube oil systems. Selection by heat load, manufacturing to specification and equivalent replacement without piping changes. Calculation and quotation within 1–2 business days.
Role in the turbine lube oil system
Why oil cooler performance directly affects turbo unit reliability
An oil cooler is an oil/water heat exchanger that removes heat from turbine oil in the turbine lubrication and control system. Oil lubricates turbine and generator bearings, heats up and returns to the oil tank; the oil cooler keeps oil temperature stable within the specified range regardless of unit load and season.
If heat exchange surface is oversized or insufficient, turbine operation is affected immediately: oil overheating reduces bearing load capacity and accelerates oil ageing; undercooling and unstable temperature worsen control performance. MO frame size is therefore selected strictly for the heat load of each lube system.
- Stable oil temperature — maintaining bearing operating conditions for turbine and generator.
- High heat transfer efficiency — maximum heat removal at moderate hydraulic resistance.
- Site-specific selection — surface calculation and MO frame size from actual parameters.
- Compatibility — manufacturing to existing connection dimensions.
Series and frame sizes: MO, MOV, MRU, DC
Oil cooler design variants and MO series frame sizes
| Series | Design | Application |
|---|---|---|
| MO series | Shell-and-tube, oil/water | Basic version for lube oil systems of low- and medium-power steam turbines |
| MOV series | Water/oil shell-and-tube | Lubrication and sealing systems of steam turbines and turbogenerators; water inside tubes, oil in shell side |
| MRU series | Floating-head shell-and-tube | Compressors and gas turbines, viscous oils; removable tube bundle for easy cleaning |
| DC series | Air cooling (oil/air) | Mainly power transformers; rarely used in steam turbine lube systems |
MO series frame sizes: MO-05MO-2MO-2,5MO-4MO-10MO-20
Small frame size
MO-05 · MO-2 · MO-2,5
Low-power turbines, mechanical drive turbines, auxiliary lube systems with small oil flow.
Medium frame size
MO-4 · MO-10
Medium-power turbogenerator sets, main and standby oil coolers in block layout.
Large frame size
MO-20
High-power turbo units with high heat load in lubrication and control systems.
Exact heat exchange surface, oil and water flow for each frame size are confirmed via the questionnaire for your turbine — this eliminates selection errors.
Heat load selection: calculator
Enter oil flow and temperatures — get an indicative heat load and required heat exchange surface. The result is preliminary; the exact frame size is fixed in the technical specification.
Oil cooler selection calculator
Indicative heat load and heat exchange surface estimate — the exact MO frame size is confirmed via the questionnaire
Input data
From the turbine lube oil system (manual/regulations)
Indicative result
Oil temperature drop15 °C
Heat load218 kW
Mean temperature difference24.5 °C
Required heat exchange surface9.9–35.5 m²
Nearest MO series frame size is selected by calculated surface area:
МО-05МО-2МО-2,5МО-4МО-10МО-20
Simplified calculation (k = 250–900 W/m²·K, oil cp ≈ 2 kJ/kg·K). Final selection — via questionnaire including fouling, water type and layout.
What next?
- We confirm oil flow, temperatures and cooling water type via the questionnaire.
- We select the MO frame size (or a replacement for your existing unit) and tube material.
- Quotation with price, dimensions and lead time within 1–2 business days.
Replacement and equivalent selection
Replace outdated or failed units without modifying piping and foundations
1
Send the mark and datasheet of the current oil cooler or its parameters: heat exchange surface, oil and water flow, connection dimensions.
2
We verify characteristics and, if needed, prepare a dimensional drawing from connection sizes.
3
Select an MO frame size (or manufacture an equivalent) with the same mounting dimensions — no piping changes.
4
Agree tube material for your cooling water type and operating conditions.
Tube materials and design options
Material selected for cooling water type and operating conditions
Brass L68, LAMsh
Classic solution for fresh cooling water: good thermal conductivity and proven reliability.
Stainless steel 08Kh18N10T
For aggressive media and higher corrosion resistance requirements for the tube system.
Copper-nickel alloys
For seawater and mineralised water where maximum corrosion and erosion resistance is required.
Block design
Main and standby oil coolers on a common frame with switching without turbine shutdown.
Regulatory references: GOST 31842-2012 (shell-and-tube heat exchangers), GOST 20689-80 (lube system water requirements), GOST R 51573-2000 (brass tubes), GOST 9941-81 (stainless steel tubes), GOST 5632-2014 (corrosion-resistant steel grades).
Delivered supplies
Turbine auxiliary equipment for power and industrial facilities
RUSTRADE supplies oil coolers and turbine auxiliary equipment for CHP plants, sugar and chemical production, oil refining and other facilities with on-site generation. See delivered projects with parameters and results in the cases section.
Frequently Asked Questions
We've collected answers to the most common questions from our clients. If you haven't found an answer to your question — contact us.
Contrary to common belief, the number in the MO series marking is not equal to the heat exchange surface area in m². For MO-2.5 / MO-4 / MO-6.3 / MO-10 it relates to the nominal cooled oil flow rate (roughly hundreds of litres per minute: MO-2.5 ≈ 100 l/min, MO-4 ≈ 160 l/min, MO-10 ≈ 400 l/min), while for some variants it is a sequential model index per the manufacturer's technical specifications. Exact surface area, oil and water flow values depend on the manufacturer and are confirmed via the questionnaire for your turbine.
These are different designs for different applications. MO — shell-and-tube oil/water coolers, the basic version for steam turbine lube oil systems. MOV — water/oil shell-and-tube coolers for turbine and turbogenerator lubrication and sealing systems (water inside tubes, oil in the shell side). MRU — floating-head shell-and-tube units for compressors and gas turbines, convenient for cleaning and viscous oils. DC — air-cooled units (oil/air), used mainly for power transformers and rarely in steam turbine lube systems.
Selection requires oil flow rate, oil inlet and outlet temperatures, cooling water temperature and type, and connection dimensions. From these we calculate heat load and required heat exchange surface, then choose an MO frame size. A preliminary estimate is available in the calculator on this page; final selection is done by our engineer.
Yes. We manufacture oil coolers to match existing connection dimensions and nozzle locations, allowing replacement of outdated or failed equipment without changing piping or foundations. To select an equivalent, send the mark and datasheet of the current unit or its key parameters.
Depending on cooling water type: brass grades L68 and LAMsh (GOST R 51573-2000 tubes), stainless steel 08Kh18N10T (GOST 9941-81, composition per GOST 5632-2014) and copper-nickel alloys such as MNZh5-1 (GOST 10092-2006). Brass is common for fresh water; copper-nickel alloys and stainless steel for aggressive or seawater. Tube material is selected for your site conditions.
GOST 9916-77 on turbine oil coolers is withdrawn; units are manufactured per industry technical specifications (e.g. TU 108-1454-87) and general shell-and-tube heat exchanger standards — GOST 31842-2012. Cooling water requirements for steam turbine lube systems are covered by GOST 20689-80 (typically fresh water not above 35 °C). The exact regulatory package is fixed in the manufacturing specification.
Standard MO series oil coolers: 2–4 months from technical specification approval; block or custom versions — 3–5 months. Quotation within 1–2 business days after calculation. Warranty — 24 months from commissioning.
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All Questions & Answers
Answers to frequently asked questions about turbogenerator units, delivery times and cooperation terms
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