Products and Services

Product : KOBELCO

Design Features >
Operator Interface/ PLC >
Additional Specs about Installation & Controls >
Sample Compressors >

About the Kobelco KNW Series:

The Kobelco KNW Series assembly is designed and constructed to exacting quality standards. These standards result in assemblies with long operating life, minimum maintenance, and low operating costs.

High Quality, Quiet and Attractive :

The Kobelco KNW Series oil-free rotary screw air compressor is designed, manufactured, assembled, and tested in the United States and is delivered ready for operation. The two-stage rotary screw compressor provides completely oil-free air because no oil is allowed in the compression chambers.
Both compression stages employ a new-patented Super Rotor design, which is acknowledged to be the most efficient, two-stage, oil-free rotary screw air compressor on the market. This new asymmetric rotor profile provides the lowest power consumption per cubic foot of compressed air.
The efficiency is further enhanced by a unique load/unload control system that is simple and trouble free.
The compressor air-end is a heavy-duty, two-stage design with each stage driven by a common gear. These components are arranged in a single modular design to form a compact unit which is mounted on vibration isolators to a structural steel base. No special foundation considerations are required.

Simple and Efficient with High Reliability :

Precision machined timing gears are mounted on each rotor shaft to maintain accurate clearances between the rotors. The bearings are anti-friction type for long life and smooth operation. The electric motor is directly coupled to the input drive shaft through a flexible coupling.
Axial thrust is reduced by incorporating an air pressure operated thrust balance piston on each stage. This arrangement minimizes thrust loading thus increasing bearing life.
The state-of-the-art programmable microprocessor controller maximizes operating efficiency and versatility. Kobelco’s sound attenuated enclosure assures quiet operation. Doors are hinged and pinned allowing easy removal for inspection and maintenance.

Design Features

High Efficiency Rotors

The new patented Super Rotor profile is the most efficient in the industry. The machined forged steel rotor sets have the most precise tolerances in the industry. FDA approved rotor coating further increases volumetric efficiency. In addition, the new profile provides 20% more displacement per revolution thus lowering rotor speeds and increasing bearing life.

Dual Vent Seals with Stainless Steel Rings

Each shaft seal consists of floating stainless steel rings and an oil labyrinth inserted between the rotor chamber and the bearings. Each seal is buffered by gas from the compression chamber which is purged to atmosphere ensuring that no lubricating oil or its vapor can enter the compression chamber.

Lubrication of Gears and Bearings

Lubrication prior to start-up, during operation and after shutdown is supplied by an independent motor driving gear pump. Compressor operation is not allowed until oil pressure is established. During the coast down period the oil pump continues to provide full lubrication until the compressor stops. This design increases gear and bearing life and is not standard on competitive units.

Capacity Control Valve

The efficient and simple capacity control system is a load/unload type with a direct operating disc valve and no discharge air recalculation. During unloading the bleed-off air is released to atmosphere through a muffler. This eliminates the need for a bleed-off cooler and the associated problem of condensed moisture entering the inlet of the compressor. The control is an electro-pneumatic device. No oil, hydraulic cylinders, or rolling diaphragms are used in the operation of this valve.

Load and Unload Control

This control provides energy efficient operation while eliminating adjustments and minimizing maintenance. When the compressor unloads the brake horsepower drops to approximately 18% of full load, significantly reducing overall energy cost. The compressor will shut down after operating unloaded for a period of time and will automatically restart on pressure demand.

Top of the page>

Kobelco Operator Interface / PLC

Versatile Display

Graphics Touch Screen Display - Readable in sunlight; 16 shades of gray allow crisp graphics and easy to read compressor data.
Trending - Three (3) configurable graphs for historical trending. Two (2) pressures or temperatures are displayed on each graph.
Package outlet air temperature display and alarm.
Service notification for air and oil filter.
Color display available as option.

Versatile Communications

Allen Bradley Micro Logix 1500 PLC Standard.
The Allen Bradley PLC allows for connection to DCS, FMS or SCADA connection by network or modem.
Ethernet Option: Allows connection to intranet for data monitoring and alarm or event notification via e-mail. Ethernet option has built in web hosting for internet connection and alarm or event e-mail notification.

Operator Interface and PLC

The Kobelco KNW Series Oil-Free Rotary Screw Air Compressor uses an Allen-Bradley Programmable Logic Controller (PLC) to control and monitor compressor operations.

Graphics touch screen display
Sunlight readable grayscale or color
Event alarm log
Pre-alarm warnings
Panel adjustable set points - temperature and pressure
Password security
Real time clock
Alternate temperature units - degree F. or degree C.
Continuous temperature displays
Maintenance reminders
Configurable graphs for trending
Ethernet option
Connection to DCS, FMS or Scada by network or modem

Top of the page>

Installation and Start-Up Supervision:

A factory trained field representative will supervise installation and start-up. This same representative will also train your maintenance personnel in the operation and maintenance of the assembly. Our commitment is to provide a trouble free, reliable installation of which we can both be proud.

Factory Monitored Maintenance Program:

Compressor performance parameters are recorded by the customer on factory-supplied forms and then examined monthly by factory experts at no charge.

Controls and Instrumentation:

Service Indicators

Air inlet filter condition indicator
Oil filter condition indicator
Oil level gauge
Routine maintenance

Pressure Indicators

First stage air discharge pressure gauge
Second stage air discharge pressure gauge
Oil pressure gauge

Temperature Indicators

First stage air discharge
Second stage air inlet
Second stage air discharge
Lube oil

Additional Indicators

Stand-by mode light
Oil pump run light
Fan run light
Compressor run light
Compressor load light
Alarm light
Hour meter - running time
Hour meter - load time
Manual unload light and switch

Safety Devices:

All safety shutdowns are indicated by message on display and alarm light.

Compressor motor overload shutdown and light
Oil pump motor overload shutdown and light
Fan motor overload shutdown and light
High first stage air discharge temperature shutdown and light
High second stage suction temperature shutdown and light
High second stage air discharge temperature shutdown and light
High oil temperature shutdown and light
Low oil pressure shutdown and light
High cabinet temperature shutdown and light
Starter failure light
Temperature pre-shutdown alarm

Additional Devices:

Start/stop push buttons
Lamp test
Audible alarm
Acknowledge switch
Reset Switch
Common alarm contracts for remote indication
RS485 network connection for DCS/FMS systems

Additional Features:

Packaged Assembly
Air-cooled or water-cooled
Integral air-cooled or water-cooled aftercooler with moisture separator and automatic drain
Cabinet ventilating fan
Easy access for maintenance
Removable hinged doors
Low installation cost
Few connections required for installation - compressed air, condensate drains, electrical and water (when required)
Control settings easily accessible
Full voltage motor starter (460 volt standard)
CSA certified panel