Coolers that keep lube oil, engine water, compressed gas, charge air and motor windings at the right temperature. Designed and built by AMI Exchangers as new units or like-for-like replacements, and supplied and supported in the GCC by Petromarsh.
Tap a part to see what it does. The red line is hot oil on the shell side, the blue line is cooling water making two passes through the tubes.
Water boxes. The front box splits the water into two passes with a partition plate, and the rear box turns it round. Both bolt off, so the tubes can be cleaned with the oil side still closed.
Tubesheets. Hold the tube ends and separate oil from water. A leak here mixes the two fluids, so the tube joints are expanded or welded and pressure tested.
Tubes. Water flows inside, oil outside. Tube material is chosen for the water: copper-nickel or titanium for seawater, brass or stainless for fresh or tower water.
Baffles. Make the oil cross the tubes back and forth. Oil is viscous and transfers heat poorly, so baffle spacing has a large effect on cooler size and pressure drop.
Shell. Contains the oil. Oil pressure is normally kept higher than water pressure, so a tube leak puts oil into the water rather than water into the oil.
Nozzles. Oil and water connections, flanged to your piping class. On a replacement they are placed to match the old unit, so no pipework changes are needed.
Vent and drain. The vent lets trapped air out when filling, and the drain empties the oil side for maintenance. Trapped air cuts the cooling surface.
Zinc anode. A sacrificial anode in the water box corrodes in place of the tubesheet and box when seawater is used. Check it at each inspection and replace it when it is largely consumed.
Skid base. The cooler sits on saddles bolted to the skid of the lube oil console or engine package, with lifting points for installation.
Engines, compressors, turbines, motors and generators turn part of their power into heat. A cooler moves that heat into water or air, so oil keeps its viscosity, gas is cool enough to compress further, and windings stay below their insulation limit.
Hot oil from bearings and gearboxes passes over the tubes on the shell side, steered by baffles. Cooling water in the tubes takes the heat. A thermostatic valve often bypasses part of the oil to hold the supply temperature steady.
An engine's jacket water circuit is closed and treated. A cooler passes its heat to raw water, seawater or a central cooling loop. Both sides are water, so a plate or a shell-and-tube unit can be used.
Intercoolers and aftercoolers cool gas between and after compression stages. Charge air coolers cool turbocharged air before it enters the engine. Motor and generator coolers cool the air circulating inside the machine with a finned-tube water coil.
Each machine has its own cooling duty and its own failure risk. Pick a type to see what it does, where it is used and what to watch for.
Cools the lube and control oil of rotating machines. It is usually a shell-and-tube with oil on the shell side, or a plate cooler where the specification allows. Critical machines have two coolers, one running and one on standby.
Gas turbine and compressor lube oil consoles in GCC gas plants and power stations.
Cools the treated water that circulates through the engine block and cylinder heads. The heat goes into seawater, cooling tower water or a central fresh water loop.
Standby generator sets and gas engine power plants.
Cooling gas between compression stages cuts the power needed for the next stage. An aftercooler cools the gas after the last stage, so moisture condenses and can be drained before the dryer or the process.
Instrument air and process gas compressors.
Cools air after the turbocharger, so the engine takes in denser air and burns fuel more efficiently with lower exhaust temperatures. It is usually a finned-tube core in a casing, cooled by water. Recoring is common when fins foul or tubes leak.
Marine engines and engine-driven power plants.
An air-to-water cooler mounted on top of or beside a large motor or generator. Air circulating inside the machine passes through a finned-tube coil, and water in the tubes removes the heat. Double-tube designs with leak detection keep water away from the windings.
Large drive motors on seawater lift and injection pumps.
On ships, platforms and coastal plants a central cooler passes the heat of the closed fresh water loop into seawater. Only this cooler sees seawater, so only it needs titanium or copper-nickel. The other coolers run on clean fresh water.
Offshore platforms and marine vessels in the Gulf.
The oil side is rarely the problem. The cooling water decides the tube material, and in the Gulf that is often warm seawater with high chlorides.
| Part | Fresh or tower water | Seawater | Special cases |
|---|---|---|---|
| Tubes | Admiralty brass, copper, carbon steelSB-111 · SA-179 | Copper-nickel 90/10 or 70/30, aluminium brass, titaniumSB-111 C70600 · C71500 · SB-338 | Stainless or duplex for wet acidic gas; finned tubes for air-side coolersSA-213 · SA-789 |
| Tubesheets | Carbon steel or naval brassSA-516 · SB-171 | Naval brass, copper-nickel or titanium-cladSB-171 · explosion clad | Stainless for wet gas coolersSA-240 · SA-182 |
| Shell | Carbon steelSA-516 Gr 70 · SA-106 Gr B | Carbon steel, on the oil sideSA-516 Gr 70 | Stainless where gas is wet and acidicSA-240 316L |
| Water boxes | Coated carbon steel or cast ironepoxy lined | Coated steel, bronze or rubber-lined, with anodesanodes in zinc or soft iron | Fabricated to match the original on a replacement |
| Gaskets | Compressed fibre or elastomer on water boxes, spiral wound on oil and gas flangesASME B16.20 · B16.21 | ||
The machine standard sets what the cooler must do. The vessel code sets how it is built. We follow both, plus your company specification.
Lubrication, shaft-sealing and oil-control systems for special-purpose machinery, including twin coolers and transfer valves.
Mechanical rules for shell-and-tube coolers, with API 660 for petroleum and gas service.
Pressure vessel rules for shell, water boxes and nozzles.
CE marking for Europe. UKCA under the Pressure Equipment (Safety) Regulations 2016 for the UK.
Compressor standards that set the requirements for intercoolers and aftercoolers in the package.
Cooling method codes for rotating electrical machines, such as IC81W for an air-to-water cooler.
Classification society rules for coolers on ships and offshore units.
Copper alloy and titanium tube specifications for seawater duty.
Non-destructive testing, and certified mill certificates for every pressure part.
Your engineers red-line our drawings, you approve the design twice before production starts, and you can witness the tests. Tap a step to see what happens and which documents you receive.
AMI Exchangers builds compressor coolers, motor and generator coolers, charge air coolers and marine coolers, and has completed more than 25,000 projects for power, marine and oil and gas clients. Petromarsh is their exclusive representative in the GCC.
For a replacement, the nameplate, the old drawing or a few photos and dimensions are usually enough. For a new cooler, send the items on the right.
