What Are the Parts of a Centrifugal Compressor Called?
A photo guide to the main components of an IHI-type centrifugal air compressor.
When you talk with a service engineer or order spare parts, it helps to know the exact names of the components inside a centrifugal (turbo) air compressor. Below are the main parts, with photos and a short explanation of what each one does.
1. Inlet Guide Vane (IGV)
Adjustable vanes at the compressor inlet. They control how much air enters the machine and pre-swirl the flow, which keeps the compressor efficient and stable at partial load.
2. Tilting Pad Journal Bearing
High-speed support bearings made of several tilting pads. They hold the rotating shaft with an oil film and run stably at impeller speeds — a critical spare part for every overhaul.
3. Shaft Seal & Vibration Monitor Probe
Shaft seals prevent oil leakage along the rotating shaft; vibration probes watch the shaft movement in real time and protect the machine from bearing damage.
4. Inlet Scroll
The spiral inlet casing that guides air smoothly from the IGV into the first-stage impeller. Its shape directly affects compressor efficiency.
5. Diffuser
Sits right behind each impeller. It slows down the high-speed air leaving the impeller and converts velocity into pressure — one of the key parts that decides compressor performance.
6. Thrust Collar
Transfers the axial forces of the rotor to the thrust bearing. Worn thrust collar surfaces are a common finding during overhauls.
7. Coolers (Air / Oil)
Bundle-type heat exchangers that cool the compressed air and the lubricating oil. Blocked or leaking cooler bundles are the most frequent cause of high-temperature alarms.
8. Impellers
The heart of the compressor. High-speed impellers add energy to the air stage by stage. Impeller condition (fouling, erosion, cracks) decides the performance of the whole machine.
9. Bull Gear & Pinion Gear
The gearbox speed-increasing gears: the bull gear driven by the motor spins the pinions at impeller speed. Gear tooth condition and bearing clearance must be checked at every major service.
10. Coupling
Connects the motor shaft to the gearbox input shaft. A worn coupling causes vibration and misalignment — always inspect it during yearly maintenance.
Bonus: Easy gearbox inspection
On IHI-type gearboxes, simply removing the gear cover exposes all moving parts — bull gear, pinion gears, shaft seals, bearings — so they can be inspected quickly without removing air or water piping.
Need any of these parts?
Turbomax supplies alternative spare parts for all components above — impellers, diffusers, tilting pad bearings, thrust collars, seals, cooler bundles, gearbox gears and couplings — for IHI T2A / TXA / TRA / TRE / T3A / TRX / TA-series and Cameron / Atlas Copco / Hanwha compressors. Send us your part name or photo for a fast quotation.