CENTRIFUGAL AIR COMPRESSOR WITH MOTOR
Air Compressor Packaged unit including motor driver. Includes inlet air filter, inlet throttle valve, bypass throttle valve, bypass silencer, compressor*, intercoolers**, aftercooler, automatic condensate removal system with condensate bypass valve, lube oil system, continuous baseplate, spacer coupling and guard, induction motor, vibration shutdown system, protection and regulation system, compressor mechanical test run and check valve.
- *The nominal 110 PSIG discharge machines have four stages of compression.
- The nominal 325 PSIG discharge machines have five stages of compression.
- **The four stage machines have three intercoolers.
- The five stage machines have four intercoolers.
The centrifugal compressor shall be a complete packaged machine. Packaging shall be consistent with good accessibility for maintenance. All equipment is heavy-duty, industrial design for long operating life.
The compressor shall be the integral gear type, directly connected at a low-speed to it's driver.
The compressor shall deliver oil-free air as specified below:
- Capacity at inlet 1,200 - 40,000 ICFM
- Barometer 14.4 PSIA
- Inlet Pressure 14.1 PSIA
- Inlet Temperature 95° F
- Relative Humidity 60%
- Cooling Water Temperature 80° F
- Discharge Pressure 100/110/125 PSIG
Compressor capacity and discharge pressure as specified above must be guaranteed with no negative tolerance in accordance with API-617 (American Petroleum Institute) specification. Brake horsepower at the motor coupling when operating at rated conditions is guaranteed with a tolerance of ± 4%.
INTEGRAL GEAR CENTRIFUGAL COMPRESSOR PACKAGE
- Compressor shall be multi-stage type with intercooling between stages.
- Compressor gearbox is to be designed for good accessibility to gears, bearings, oil seals, and air seals. All compressors must be horizontally split gear case design. Design must allow maintenance of compressor parts without affecting shaft alignment.
- Compressor casings or scrolls to be cast steel or cast iron.
- Impellers shall be the radial or backward-leaning bladed, open inducer type, made of wear and corrosion resistant stainless steel. Impellers, pinions, and bull gear to be dynamically balanced and overspeed tested at 110% of maximum continuous operating speed during compressor factory test.
- All scrolls and intercoolers to be pressure tested at 150% of working pressure.
- Speed increasing gear shall be single step, high speed helical type and designed in accordance with AGMA standards. Pinion teeth to be hardened and ground.
- Axial impeller thrust shall be absorbed by Kingsbury type thrust bearings on the pinions to provide safety in case of compressor surging or stonewall operation. Bull gear thrust bearings shall be babbitted, tapered, land type. Anti-friction bearings are not acceptable.
- High speed pinion bearings shall be the anti-whip, tilting shoe type bearing or hydrostatic squeeze film. Bearing shall allow low vibration level operation with compressor unloaded to 12-15% no load
- All bearings and each gear mesh shall be pressure lubricated.
- Compressor shall deliver oil free air and avoid oil leaks by use of labyrinth type, non-wearing seals. A separate horizontally split labyrinth oil and air seal with an open air space between seals is preferred to insure oil free air delivery. If a combination air/oil seal is supplied, a seal buffer air system shall be furnished to maintain the compressor oil free during start-up and unloaded operation periods. Carbon ring seals are not desired.
- Intercoolers shall be the tube and shell, extended surface type with air in the shell and water in the tubes. Tubes shall be 5/8" OD or 3/8" OD admiralty or copper material with aluminum or equal, fins.
- Intercoolers shall be packaged on compressor base so they are accessible for maintenance and/or removal without major disassembly, disturbing air piping, and disturbing compressor
shaft alignment. Straight tubes which can be mechanically cleaned in place are preferred.
- Intercoolers shall be constructed and stamped in accordance with ASME Code for Unfired Pressure Vessels, where applicable.
- D. Adequate moisture separation facilities shall be included with the intercoolers to allow efficient removal of condensate. Vortex, inertial, or demister pad systems are acceptable.
- Lubrication system mounted and assembled on compressor base. System consists of:
- Oil reservoir with minimum five minute retention time.
- Main and auxiliary oil pumps, each with different driver. Acceptable drivers are separate electric motor, air motor, steam turbine or main shaft.
- Oil coolers, tube and shell type.
- Full flow oil filter, 10 micron size.
- Necessary oil pressure regulator, carbon steel piping, fittings, and gauges.
- Low oil pressure switch to start auxiliary oil pump on decreasing pressure.
- Low oil pressure switch to shut down compressor in case oil pressure decreases to dangerous level.
- High oil temperature switch to shut down compressor in case temperature increases to unsafe level.
- Flexible gear shaft coupling, grease lubricated, or nonlubricated disc type coupling with coupling guard
COMPRESSOR CONTROL SYSTEM
A compressor control system shall be furnished to automatically operate the machine as a base load unit and further operate the machine efficiently on intermittent duty, loading and unloading the unit as required.
The control system shall include regulation of the compressor throttle valve to prevent overloading the drive motor during periods of low ambient temperature. The components listed below shall be included as a minimum in the control system:
1. Inlet butterfly valve and pneumatic operator or inlet guide vane.
2. Blow-off valve, pneumatic or electric operated.
3. Discharge check valve.
4. Pressure switch and other instruments required to actuate load and unload valves.
5. Controller, transducer, pneumatic relay and other instruments required for operation of the motor overload control.
6. High interstage air temperature shut down switch.
7. Non-contact inductance probe-type vibration monitor system with one probe for each impeller furnished. Probes are preferred to be mounted in overhung shaft area immediately behind the impellers. Monitor shall be double setpoint type for separate alarm and shut down features.
8. Compressor control panel, NEMA 1 enclosure, wall or machine mounted, complete with indicating lights for auxiliary pump operation, pressure switches, temperature switches, vibration monitor, panel power, and permissive safe starting. Also includes discharge pressure gauge, control reset button, alarm silence button, auxiliary pump test button.
Compressor driver motor shall be voltage as required, 3 phase, 50 or 60 cycle, open, drip proof induction type. Class B insulation, 90°C rise at full service factor of 1.15 or 1.25. Motor shall have sleeve or anti-friction bearings and meet NEMA design criteria. Motor shall be mounted on compressor base.
Compressor package at all operating conditions shall have a noise level which is in strict accordance with the requirements of OSHA. Compressor noise measurements are to be made at points one meter from the equipment following the procedures of the CAGI-PNEUROP Test Code.
The following accessories shall be furnished:
1. Two stage inlet air filter/silencer including weather hood for outdoor installation.
2. Inlet and discharge flexible connections for compressor air piping.
3. Condensate traps for intercoolers and aftercoolers.
4. Pipeline type, straight tube, air aftercooler with moisture separator. Designed for 15°F air exit approach temperature with 80°F cooling water. Aftercooler to be ASME Code stamped.
5. Blow-off air silencer. Mounted directly on blow-off valve remote from compressor for maximum noise attenuation.
Compressor shall be given a full operating test at the factory to determine its mechanical and aerodynamic characteristics. Vibration levels should be recorded at various speeds, including 10% over-speed, to
assure the location and safe magnitude of critical speeds. Compressor air capacity, pressures, and temperatures shall be measured and recorded. Horsepower will be determined using ASME Test Code procedures. Compressor surge point and stonewall condition shall be demonstrated during the test. A test curve related to guarantee conditions will be submitted to the purchaser.
Use the Table - Graph below to select the model to meet requirements.
A Number of Custom Performances, Designed from Standard Components
- Two-stage TA compressors for glass manufacturing, and pharmaceuticals.
- Three-stage TA for large manufacturing, textile fiber, and process applications.
- Four-stage TA and MSG® for chemical processing needs.
- Packaged five- and six-stageMSG® models are available for soot blowing electric utilities and high pressure boosting.
- Four-stage double gearboxMSG® compressors for high pressure liquifying and soot blowing service.
- Three pinion single gearbox or double gearbox TA and MSG® arrangements for combined service compressors and high pressure applications.