Emerson VSSG, VSG manual RTDs and Pressure Transducers, Control System, Theory of Operation

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This is a continuous cycle.

Section 2 • Theory of Operation

suction. The discharge temperature of the compressor must be kept a minimum of 30°F (or 17°C) above the dis- charge gas dew point to prevent the condensing of liq- uids in the oil separator. The oil separator shell and legs must be insulated when the gas stream has a high prob- ability of having condensables.

Oil in the gas compressor unit serves three primary pur- poses. They are compressor lubrication, sealing clear- ances between moving parts, and heat removal result- ing from heat of compression and friction. Initially, oil flow is driven by a mechanical gear pump (7). Once the system reaches design conditions, the oil pump is shut off and oil flow is maintained by differential pressure in the gas system.

As the oil is separated from the gas in the oil separator, it is pumped or syphoned through an oil cooler (9), then filtered through a single (11) or dual oil filters (15) and back to the injection port of the compressor (14). The standard oil cooler is a shell and tube water cooled heat exchanger (9). The other option is to air cool oil remotely through a finned fan heat exchanger (8).

Furthermore, to collect oil from the coalescing side of the oil separator (12), a line is installed between the oil separator and the compressor. By opening the shut-off valve (6), this will allow oil dripping off the coalescing fil- ters to be fed back to the compressor. In addition, the oil cooler (8 or 9) is piped in parallel to the oil temperature control valve (oil mixing vlave) (10), which acts as a by- pass valve.

On units with a full-time oil pump, oil pressure is regu- lated by the oil pressure regulator (12). It controls up- stream pressure to the compressor bearings and should be adjusted to hold the oil pressure at 20 psig above suc- tion pressure. Excess oil not required for bearing lubrica- tion is passed through the regulator and back into the oil separator (13).

This is a continuous cycle.

RTDs and Pressure Transducers

Resistance Thermometers (RTDs) and pressure trans- ducers are instruments used to measure temperatures and pressures at specific locations on the gas compressor unit, see Figure 1-2. Gas Compressor Unit Components. RTDs are typically mounted on the suction pipe, dis- charge pipe, oil separator and oil filter outlet pipe. Pressure transducers are typically mounted on the block and bleed assembly and directly on the suction pipe. The pressure transducers measure suction pressure, inlet and outlet oil pressure, and oil separator pressure.

Control System

The gas compressor unit is controlled by a Programmable Logic Controller (PLC) panel. This PLC panel’s main func- tion is to control the gas compression system from the data that it receives from the sensors around the unit. Refer to Compact Logix PLC manual (35391CL) for addi- tional information.

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VSG/VSSG • Installation, Operation and Maintenance Manual •Vilter/Emerson • 35391SSG

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Contents Installation, operation & maintenance manual VSG/VSSG compressor unitPage VSG/VSSG Standard Vilter Warranty Statement Vilter Manufacturing LLC Important MessageREAD CAREFULLY BEFORE INSTALLING AND STARTING YOUR COMPRESSOR Table of Contents Section 3 InstallationSection Title Section 1 General InformationSection 5 Maintenance/Service Section 6 TroubleshootingSection Number Section 4 OperationSection 7 Warranty and Parts List of Tables and FiguresAppendices Table/FigureFigure 3-12. Installation of Coolers - Next to Buildling Section 1 General Information How To Use This Manual Section 1 General Information Gas Compressor Unit Model Designations Figure 1-1. Gas Compressor Unit Model DesignationSection 1 General Information System Unit Identification Figure 1-2. Gas Compressor Unit Components 1 of Section 1 General InformationCompressor Unit Component Identification Figure 1-2. Gas Compressor Unit Components 2 of Section 1 General Information Component Identification Continued Figure 1-2. Gas Compressor Unit Components 3 ofSection 1 General Information Piping & Identification Component Tags 3-Way Thermostatic Valve Symbols and IdentificationsPosition Transmitter High Side Float Valve Steady-Mount Bulb & Capillary 1 - 10 / Blank Section 2 Theory of Operation Gas FlowOil Life and Oil Flow Figure 2-1. Gas Compressor Unit P&IDThis is a continuous cycle RTDs and Pressure TransducersControl System Section 3 Installation Delivery InspectionRigging and Lifting of Compressor Unit Figure 3-1. Rigging and Lifting PointsLong Term Storage Recommendations The following are recommendations regarding long term storageAIR COOLED OIL COOLERS Compressor Unit Inspections Prior to Storage or InstallationRecommended Onsite Tools LONG TERM STORAGE LOG Compressor has been placed in operation as ofFoundation Foundation MaterialsConsiderations Prior to Starting Building the FoundationCompressor Unit Installation of both Check the ability of the soil to carry the loadLeveling and Grouting recommendations for setting, precautions, mixing, andAdditional Information Codes and Standards Figure 3-6. Housekeeping Pad Dimension Detail - Top View 2 - # CLOSED TIES CENTER LINE 5 - # 6 VERTLEVEL COMPRESSOR UNIT HOUSEKEEPING PADSPiping 010Ä5*4+0- 214176 4%1//0&& 14 175-2+0 10%46 $#5Table 3-2. Maximum Allowable Flange Loads Nozzle Dia. inFz lbf Fy lbfONE FAN DIAMETER NOT PREFERRED HOT AIR RECIRCULATION PREFERRED Figure 3-14. Cooler Placement and SpacingFigure 3-13. Discharge Elevation of Coolers Pressure Testing Initial Oil Charging Using Non -Vilter OilsUnit Oil Charging and Priming Do not hydro test compressur unit. Failure to complyBypass Valve Normal Operating Level Maximum NON-Operating LevelMinimum Operating Level SUCTION INLET CLOSEOIL MIXING OPEN VALVESection 3 Installation Initial Oil ChargingPriming Remote Oil Cooler and Piping REMOTEMOTOR SUCTION INLETOIL FILTER OPEN Section 3 Installation Pre Start-Up Pre Start-Up Checklist15. Verify that all valves are in the open position Section 3 Installation Start-Up Section 4 Operation OperationOil Inspection Dual Oil FiltersControl System Calibration Stopping/RestartingStarting, Stopping and Restarting the Compressor Starting Calibrate Slide Valve ActuatorsFigure 4-2. Actuator Assembly Section 4 Operation Figure 4-4. Slide Valve Calibration Screen Compact Logix PLC Figure 4-5. Photo-chopperCapacity Table 4-1. Command Shaft Rotation SpecificationsAngle/Slide Travel Oil Temperature Control Valve Oil Mixing Valve Operation 18. Press the “Set Max” buttonFail Position Purging with Dry Nitrogen 10. Close discharge bleed valve while still purging OIL SEPARATOR Purging with Dry GasPressure Indicator Section 4 Operation Figure 4-12. Suction Bypass Valve and Equalizing Solenoid Suction Oil Figure 4-13. Suction Oil Charging ValveCoalescing Oil Return Line Setup Table 5-1. Maintenance/Service Schedule Oil CircuitUnit ControlSection 5 Maintenance/Service Maintenance/ServiceMaintaining Proper Operation Compressor Unit Isolation forCompressor Unit Leak Check Oil System Components Oil Sampling Use Vilter Oil Analysis Kit VPN 3097A to collect an oilsample for analysis. For an example, see Figure 5-2. Fill Send samples immediately to the oil analysis lab afterOil Charging Oil Filter Replacement Single Oil Filter AssemblyDual Oil Filter Assembly Oil DrainingVent Valve Drain Valve Inlet Shut-Off Valves Centering Strap Coalescing Filter ReplacementCoalescing Filter Oil Pump Strainer View From Back of Oil Pump StrainerSize Drive Coupling Form-Flex BPU Hub InstallationTable 5-3. Shaft and Hub Distances Drive Center Member Installation and Alignment 17. Install set screw in hub cap to secure key in keyway of shaftAngular Alignment Table 5-5. Disc Pack Installation Torque SpecificationsTable 5-4. Hub Clamp Bolt and Set Screw Torque Specifications Drive Coupling Type C Sure-Flex Replacement Drive Coupling Form-Flex BPU Center Member and Hub RemovalCompressor Replacement Table 5-6. Clamping Bolts and Set Screw Torque SpecificationsLock Washer Compressor Shaft Bearing Float Inspections Figure 5-11. Bearing Axial Float InspectionGate Rotor Float and Gate Rotor Bearing Float Inspection Table 5-7. Maximum Bearing FloatFigure 5-12. Bearing Radial Float Inspection Figure 5-13. Gate Rotor FloatTable 5-8. Gate Rotor Float Figure 5-14. Gate Rotor Bearing FloatApplied Force Rigidly attach dial indicator Use bolt for fulcurm Gate rotor bearing float being measuredSection 5 Maintenance/Service Gate Rotor and Support Clearance Figure 5-15. Gate Rotor and Support Clearance - Minimum ClearancesFigure 5-16. Gate Rotor and Support Clearance - Measuring Gate Rotor Support Gate Rotor Gate Rotor Support Gate RotorGate Rotor Support Gate Rotor Straight Edge Straight Edge Straight EdgeTable 5-9. Gate Rotor Tool Sets Gate Rotor Assembly Replacement All VSG & VSSG Compressors ExceptVSG 301-701 Compressors Figure 5-17. Gate Rotor Assembly Removal and Tools Figure 5-18. Gate Rotor Assembly RemovalFigure 5-19. Gate Rotor Assembly and Tools Figure 5-20. Gate Rotor and Shelf ClearanceGate Rotor Assembly Replacement VSG 301-701 Compressors ONLY Figure 5-21. Gate Rotor Assembly BreakdownFigure 5-23. Gate Rotor and Shelf Clearance Figure 5-22. Gate Rotor Thrust BearingFigure 5-24. Gate Rotor Blade Assembly Gate Rotor DisassemblyFigure 5-25. Gate Rotor Blade Installation Figure 5-27. Thrust Bearing Installation Figure 5-26. Gate Rotor Thrust BearingSlide Valve Actuator Assembly Replacement Figure 5-28. Roller Bearing AssemblyFigure 5-29. Command Shaft Seal Command Shaft Assembly ReplacementCommand Shaft Seal Replacement Figure 5-30. Command Shaft Seal Installation Section 6 Troubleshooting ProblemSolution Table 6-1. Slide Valve Actuator Troubleshooting Guide 1 ofTable 6-1. Slide Valve Actuator Troubleshooting Guide 2 of Table 6-2. Slide Valve Actuator LED Blink Codes* 1 of Flash PatternMeaning er before the calibration procedure was completed. The actuator will not move while this error code is displayed. To clear the errorcalibrate the actuator. If this error has occurred and the cause was not the loss of 24V power during calibration, possible causes areTable 6-3. Troubleshooting Guide - General Problems & Solutions 1 of Table 6-3. Troubleshooting Guide - General Problems & Solutions 2 of Table 6-3. Troubleshooting Guide - General Problems & Solutions 3 of 6 - 8 / Blank Section 7 Warranty and Parts Warranty Claim ProcessingOn Site Service Support Warranty does not cover labor and extraneous expensesRemanufactured Gas Bare Shaft Compressor Process Request a “VSG Single Screw Compressor Rebuild Form”Torque Specifications for 17-4 Stainless Steel Fasteners ft-lbs Appendix A Torque SpecificationsTorque Specifications ft-lbs Appendix B Motor Compressor - General Storage Instructions Appendix C Oil Analysis Report EvaluationPRODUCT ANALYSIS REPORT No Action RequiredAppendix D Recommended Header Piping INLET ON BOTTOM Appendix E Recommended Remote Air Cooled Oil Cooler PipingOUTLET ON TOP Blank
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