Principle of the centrifugal compression

Air or gas gain kinetic energy, that is, velocity, as they go through an impeller.
The air or gas introduced into the impeller turns at a right angle to the direction of its primary inlet
and is spread through a diffuser while gaining centrifugal force through the rotator and showing a rapid rise in pressure.
As a result, the air or gas that passed the impeller enters the diffuser with reduced velocity and increased pressure.
This process introduces velocity or kinetic energy from the rotator into the diffuser,
a fixed object, and transforms it into fixed energy or pressure.
The air or gas that came through the diffuser completes its transformation into pressure at a volute.

Centrifugal Air Compressor Korea

pressure generation curve

Centrifugal Air Compressor Korea

comparision with other compression

Centrifugal Compressor PD Compressor
Compression
Principle

A turbo-type compressor works not through the volume
displacement method but the continuous flow method, which enables the production of high-quality pressed air without oil and pulsation. Its compression principle is as follows:

1. Air flows in at high speed through the inlet through a fast-rotating impeller.

2. The air that flows in at high speed has velocity energy.

3. As the air that flew in through the impeller enters the diffuser, the velocity energy of the air is transferred into potential energy (pressure increased).

In the two cylinders (low-pressure and high-pressure), a piston reciprocates to reduce the volume of the inhaled air to obtain the required pressure.

Positive displacement type :

The movement of the motor needs to be changed from a circular motion to a straight-line motion; many moving parts are needed for a power transmission device; the straight-line motion inevitably results in vibration and abrasion of many parts.

Operation During continuous operation, the pressure in the system is automatically detected, and the operation is implemented in the automatic loading or unloading state depending on the amount of the required air at the time. An automatic regulating system also needs to be attached to adjust the amount of the required air, and many parts are subject to abrasion; sudden and frequent malfunction occurs, posing a serious challenge for continuous operation.
Power
Consumption

Only little abrasion is seen at the power connecting part unlike in a reciprocating movement; high efficiency can be maintained, which leads to power saving.

As an air inhalation adjustment device is attached, one can use only the required amount of air, thereby resulting in electricity cost reduction.

The ampere level plummets under 60% when unloading; electricity cost can be saved in a no-load state.

With the abrasion of many parts used for a reciprocating movement, the efficiency rapidly falls under 70% after one or two years, requiring high power consumption.

With this rapid drop in efficiency and need for frequent part replacement, the global market for this kind of compressor shows a declining trend.

Foundation
and
installation
work

There is little vibration during operation; foundation work and anchoring are not required at all.

Only power connection, air piping, and coolant (water cooling) piping are required for the machine; no additional equipment is needed to be installed by the customer.

With the inevitable vibration from a reciprocating movement, special concrete work and anchoring are needed, which entail a large workforce and high cost.

i.e., required resources for a 300 HP compressor :

Workforce : 6–7 I Period : 10–15 days I Cost : KRW 3,000,000 Particular attention is needed when placing the equipment near walls and installing inlet pipes and the like to prevent mesomerism caused by vibration.

Maintenance

When shipped from a factory, the required parts are fully assembled in a package, which makes the test run easier; there is no abrasion because the direct friction does not decrease the efficiency after long-term use.

With the compressor’s simple structure, service for operation is extremely simple, which leads to low maintenance cost. Safe and automatic operation equipment is fully provided; perfect for unmanned operation.

Overhauling is required at least once a year to replace parts including a piston ring or valve packing; frequent maintenance is needed, whereas the margin of efficiency decline is broad.
Vibration The compressor’s rotation system always maintains balance at a certain level and does not entail vibration; a foundation work is not required, which saves foundation work cost. The machine vibrates because of reciprocating movement; a sturdy foundation is needed.
Efficiency No contact in the compression process and no abrasion; high performance can be maintained even during long-term operation. The reciprocating movement of a piston in a cylinder causes the abrasion of a piston ring or the like; the performance declines remarkably after long-term use.
Pulsation

The compressor’s rotation compression system does not entail pulsation of the discharged air.

Therefore, the diameter of the pipe through which the air is discharged may be small; a receiver tank might not be required depending on the purpose of use.

The reciprocating movement of a piston leads to the pulsation of the discharged air; pipes with long diameters are needed, and a receiver tank must be provided.

The pulsation of the air leads to machine vibration.

Discharge
temperature
The discharge temperature is relatively low, at about 110°C and 40°C before and after going through an aftercooler. The discharge temperature is 150°C or higher; an aftercooler with a large capacity must be installed.
Occupying
space
The compressor includes a motor and control box equipped inside, which occupy very little space. Compared to a turbo compressor with the same horsepower, the equipment needs to occupy about two to four times more space.
Noise Produces less noise than the reciprocating type with the same horsepower, which is generally at 85 dB or lower. Low-speed rotation generates low-frequency noise, which is hard to reduce; mesomerism caused by vibration amplifies the noise.

Main Features

Centrifugal Air Compressor Korea

Non -
Contact rotation

Centrifugal Air Compressor Korea

Non -
contact compression

Centrifugal Air Compressor Korea

Non -
use lubricant

structure

It has the following core parts : the impeller that compresses the air,
a high-speed motor that rotates the impeller at high speed, and a foil air bearing that supports the rotating parts.

Centrifugal Air Compressor Korea

core components

Centrifugal Air Compressor Korea

Impeller

Centrifugal Air Compressor Korea

foil air bearing

Centrifugal Air Compressor Korea

High speed motor