Details

1. Introduction
The Compressor Test Rig is engineered to evaluate and characterize oil-flooded rotary screw compressor lubricating oils under realistic, controlled conditions. Its primary function is to run an oil-injected rotary screw compressor—typically an Atlas Copco GA 15 A 13 (or
equivalent)—in a closed loop, while continuously monitoring pressure, temperature, flow, and related parameters. By subjecting test oils (ISO VG 32–100) to sustained operation, downstream components can be inspected to draw conclusions about oxidation stability,
wear properties, and overall performance under load.

Key objectives include:
 ● Oil Performance Assessment: Determining oxidation tendency and longevity of compressor oils.
 ● Data-Driven Diagnostics: Capturing real-time data (pressure, temperature, flow) via an integrated DAQ/PLC system for post-test analysis.
 ● Safety and Standards Compliance: Designed to meet the European Machinery Directive 2006/42/EG (CE) or equivalent Indian standards, with interlocks, safety relief valves, and emergency shutdowns.

2. Technical Specifications

  

    
Parameter
    
Specification
  
  

    
Compressor Type
    
Oil-flooded rotary screw (Atlas Copco GA 15 A 13 or equivalent)
  
  

    
Motor Power
    
15 kW (20 HP)
  
  

    
Input Voltage
    
415 VAC, 3-phase, 50 Hz, 63 A
  
  

    
Maximum Discharge Pressure
    
12.5 bar (nominal); safety relief at 14 bar
  
  

    
Maximum Flow Rate
    
71 CFM (≈ 120 m³/h) at 130 °C
  
  

    
Oil Grades Supported
    
ISO VG 32, 46, 68, 100
  
  

    
Oil Tank Capacity
    
500 L, vertical steel vessel (IS 2062 E 250 BR), hydro-tested to 15 bar
  
  

    
Flow Meter Range
    
0–150 LPM (turbine type, 4–20 mA output)
  
  

    
Pressure Transmitters
    
Suction: 0–2.5 bar abs (Wika S20)
Discharge/Reservoir: 0–16 bar gauge × 4 (Wika S20)
  
  

    
Temperature Transmitters
    
0–150 °C (Wika TR 10 × 5, 6 mm probe)
  
  

    
Cooling System
    
Oil cooler + circulation pump (≤ 130 °C outlet); air cooler + separator downstream
  
  

    
Reservoir Safety Valve Setpoint
    
14 bar (drain at 12.5 bar via angle-seat valve)
  
  

    
HMI/DAQ Hardware
    
PLC: Siemens SIMATIC S7-1200
Industrial PC: Intel i7, 8 GB RAM, 1 TB HDD, Windows 10 Pro, 21″ TFT monitor
  
  

    
Control Panel (VFD)
    
Schneider ATV212, 22 kW, 3-phase, with MCCBs, overload relays, pushbuttons, tower light, E-stop
  
  

    
Safety Interlocks
    
Over-temperature (> 130 °C → VFD shutdown), over-pressure (> 14 bar → relief), low oil level alarm
  
  

    
Footprint (Approx.)
    
2.5 m × 1.5 m × 1.8 m (composite of compressor skid, panels, reservoir)
  
  

    
Compressor Skid Dimensions
    
1.3 m × 0.78 m × 1.2 m
  
  

    
DAQ Cabinet Dimensions
    
0.6 m × 0.8 m × 1.8 m
  
  

    
VFD Control Panel Dimensions
    
0.8 m × 0.3 m × 1 m
  
  

    
Reservoir Dimensions
    
Ø 1 m × 1.2 m
  
  

    
Material of Construction
    
Skid: IS 2066 MS plate (10 mm) + ISMC-100 channels; Reservoir: IS 2062 E 250 BR steel; piping: SS/PK
  
  

    
Paint/Coating
    
Powder coat on skid; primer + anticorrosive topcoat on reservoir
  
  

    
Instrumentation Accuracy
    
Pressure: ± 1 % FS (Wika 233.50.100)
Temperature: ± 0.5 °C (Wika TR 10)
  


3. Main Functional Blocks
The rig is divided into four primary subsystems, each forming a cohesive test loop:
 1. Compressor Assembly 
  - Machine: Oil-injected rotary screw compressor driven by a 15 kW electric motor.
  - Operation: Carries test oil through internal bearings and screws, then discharges oil-laden air into the separator.

 2. Power Control Unit (VFD Panel)
  - Variable Frequency Drive: Schneider ATV212 (22 kW, 3-phase) regulates motor speed to maintain setpoints for pressure, temperature, or flow.
  - Electrical Panel: Houses MCCBs, pushbuttons, tower light (red/yellow/green), emergency stop, and interlocks for motor over-temperature, over-pressure, and fault conditions.

 3. Data Acquisition & Control (DAQ/PLC)
  - PLC: Siemens SIMATIC S7-1200 for all analog/digital I/O.
  - HMI/Industrial PC: Advantech industrial computer (Intel i7, 8 GB RAM, 1 TB HDD, Windows 10 Pro) with proprietary software screens for real-time monitoring.
  - Sensors:
   ▪ Pressure transmitters (Wika S20, 0–2.5 bar abs; 0–16 bar gauge) at suction, discharge, and reservoir.
   ▪ Temperature transmitters (Wika TR 10, 0–150 °C, 6 mm probe) before/after oil cooler and at compressor discharge.
   ▪ Flow meter (turbine type, 0–150 LPM, 4–20 mA output) on the oil circuit.
   ▪ Energy meter (as per requirement) to measure electrical power consumption.

4. Air/Oil Cooling & Storage
  - Oil Cooler + Circulation Pump: Maintains oil inlet temperature to compressor; controlled by VFD to keep outlet ≤ 130 °C.
  - Air Cooler + Separator: Cools compressed air and separates oil before storing in reservoir.
  - Reservoir: 500 L vertical steel vessel (IS 2062 E 250 BR), hydro-tested to 15 bar, with lifting hooks, drain valve (½″ BSPM), and gauge ports (¼″ + ½″ BSPM).
  - Safety Valve: Set at 14 bar on reservoir; drains automatically at 12.5 bar via angle-seat valve.

4. Detailed Hydraulic Circuit (see in attached documents)
A closed-loop oil circuit passes as follows:
 1. Oil Injection: Oil from tank (“Cold Oil”) is pumped into compressor bearings.
 2. Discharge Separation: Mixed oil + air enters the air/oil separator; oil drains back to tank; air passes through the air cooler.
 3. Oil Cooling: Separated oil flows through an oil cooler (temperature transmitters 6.3/6.4).
 4. Flow Meter (7.0): Measures oil flow (0–150 LPM).
 5. Sampling Point: Allows manual oil sampling for lab analysis.
 6. Safety Valve (8.0): Protects circuit from overpressure beyond 14 bar.
 7. Oil Tank (9.0): 500 L capacity; equipped with level indicators, drain, and inspection ports.
 8. Return to Compressor: Oil recirculates to compressor’s injection port (pressure transmitter 5.1 reads 0–16 bar gauge).

The hydraulic schematic labels:
● 1.0 = Compressor suction
● 2.0 = VFD panel
● 3.0 = Energy meter
● 4.0 = Suction pressure transmitter
● 5.1–5.5 = Pressure transmitters on discharge/reservoir
● 6.1–6.6 = Temperature transmitters around coolers
● 7.0 = Flow meter
● 8.0 = Safety valve
● 9.0 = Oil reservoir
● 10.0 = Auto drain valve on reservoir
● 11.0 = Pressure gauge
● 12.0 = Air dryer (for clean compressed air supply)
● 13.0 = Optional instrumentation (e.g., dew-point sensor).

5. Mechanical and Structural Components
1. Base Skid & Frame
 o Fabricated from ISMC-100 channels (legs) and 10 mm thick MS base plate (IS 2066), welded per approved drawings, powder-coated.
 o Lifting hooks (16 mm thick MS) at four corners, rated for safe jack and crane handling.

2. Air Reservoir & Manifold
 o Shell and dish ends: IS 2062 E 250 BR, ellipsoidal ends, hydro-tested to 15 bar.
 o Manifold blocks machined from MS; fitted with ½″ BSPM sockets, dye-penetrant tested.
 o Painted in primer + topcoat; 24 hr dry time.

3. Piping & Fittings
 o High-pressure rated tubes (SS/PK) and fittings connecting compressor, cooler, reservoir, and valves. All joints leak-tested at 18 bar.
 o Auto-drain valve (Parker/Festo, ½″ BSPM) on reservoir bottom; air-operated angle-seat valve (Parker/Festo, ½″ BSPM) for pneumatic control.

4. Cooling Package
 o Oil and air coolers sized to maintain oil ≤ 130 °C (critical shutoff at 130 °C).
 o VFD-controlled fan/motor assembly for variable cooling based on discharge temperature.

5. Instrumentation Mounting
 o Pressure gauges (Wika 233.50.100, 0–21 bar, 1 % FS) on suction/discharge lines and reservoir.
 o Gauges/transmitters mounted on SS sockets (SA-105, 3000#) with isolation valves.
 o Flow meter (turbine, 1″ BSPF) mounted downstream of oil cooler.
 o Temperature transmitters in 6 mm thermowell, inserted before/after oil cooler and at discharge.

6. Electrical & Control Architecture
 ● Power Input: 3-phase, 415 VAC, 63 A (customer-supplied).
 
 ● VFD Panel:
     - Schneider ATV212 (22 kW).
     - MCCB, overload relays, fuses, contactors, motor protection.
     - Pushbuttons: START, STOP, RESET; Emergency Stop (mushroom head).
     - Tower light (green = ready, yellow = running, red = fault).
 
 ● PLC/DCS Cabinet:
     - Siemens S7-1200 CPU with analog inputs for 4–20 mA loops (pressure, temperature, flow).
     - Digital I/O for interlocks, alarms, motor/valve control.
     - SMPS and MCBs per schematic.
     - Ethernet link between PLC and industrial PC.
 
 ● HMI/Industrial PC:
     - 21″ TFT monitor, keyboard, mouse.
     - Graphical interface with mimic diagram showing real-time tank level, oil temp, pressures, alarm status.
     - Logging of all parameters; export to CSV/Excel for post-test analysis.
 
 ● Safety Interlocks:
     - Over-temperature (oil > 130 °C → VFD shutdown).
     - Over-pressure (reservoir > 14 bar → safety relief valve, alarm).
     - Low oil level → interlock to stop compressor.
     - Password protection on HMI to prevent unauthorized changes.

7. Bill of Materials (Key Items)


  

    
Item No.
    
Part Number
    
Description
    
Make/Model
    
Qty
  
  

    
1
    
2A3876P0001
    
Oil-Injected Rotary Screw Compressor, 20 HP/15 kW
    
Atlas Copco GA 15 A 13
    
1
  
  

    
2
    
2A3876P0002
    
VFD (22 kW, 3Ø)
    
Schneider ATV212
    
1
  
  

    
3
    
2A3876P0003
    
Energy Meter (as required)
    
Standard
    
1
  
  

    
4
    
2A3876P0004
    
Pressure Transmitter, 0–2.5 bar abs
    
Wika S20
    
1
  
  

    
5
    
2A3876P0005 (×4)
    
Pressure Transmitter w/ Cooling Element, 0–16 bar
    
Wika S20
    
4
  
  

    
6
    
2A3876P0006 (×5)
    
Temperature Transmitter, 0–150 °C
    
Wika TR 10
    
5
  
  

    
7
    
2A3876P0007
    
Flow Meter, 0–150 LPM (Turbine Type)
    
Standard
    
1
  
  

    
8
    
–
    
VFD (Additional, as per requirement)
    
Standard
    
1
  
  

    
9
    
2A3876P0009
    
Oil Tank, 500 L, 15 bar, Vertical Mount
    
Neometrix
    
1
  
  

    
10
    
2A3876P0010
    
Pressure Gauge, 0–21 bar, 1 % FS
    
Wika 233.50.100
    
1
  
  


8. Quality Assurance & Testing Protocols
8.1. Factory Acceptance Test (FAT)
Before dispatch, each rig undergoes:
 ● Hydraulic Integrity: Leak test at 18 bar; all piping/fittings confirmed leak-proof.
 ● Pressure/Temperature Accuracy: Calibration certificates for all transmitters from NABL-accredited labs.
 ● Visual Inspection: Dimensions (≈ 1.3 m × 0.78 m × 1.2 m for compressor skid), correct labeling, mounting of pushbuttons and gauges.
 ● Air Reservoir: Hydro test certificate, welding records, lifting hook integrity, correct port sizes (¼″ × 2, ½″ × 2, inlet/outlet 1½″ × 2).
 ● Safety & Interlocks: Emergency stop, alarm buzzer, tower light, motor interlock, relief valve verification, HMI password protection.
 ● Functional Test:
   • Ramp VFD stepwise; verify compressor startup.
   • Oil cooling performance: record inlet/outlet temps (40–84 °C range); ensure ≤ 130°C cutoff.
   • Pressure tests: log suction, operating, and discharge pressures every 10 min; confirm reservoir drains at 12.5 bar, relief at 14 bar.

8.2. Site Acceptance Test (SAT)
After installation at BPCL (within three weeks):
 ● Mechanical Installation Check: Verify foundation, leveling, alignment per site layout.
 ● Electrical Hookup Verification: Confirm incoming power (3 Φ 415 VAC, 63 A), earthing for power/instruments, and cable routing.
 ● Functional Run: Full-load run for 4,000 hr (minimum expected compressor reliability) under supervised conditions.
 ● Documentation Handover:
   1. Hard/soft copy of User Manual & Maintenance Manual (× 2 each).
   2. Complete technical drawings (GA, circuit, BOM).
   3. Compressor test certificate, 2-year warranty certificate.
   4. Training for BPCL operators by Neometrix service engineers.

9. Operational Workflow
1. Start-Up Sequence
 ● Verify oil level in tank; fill to mark.
 ● Close reservoir drain valve.
 ● Switch on VFD panel; set VFD parameters (target RPM/pressure).
 ● Power up PLC/PC; launch HMI application.
 ● Press “START” on HMI; VFD ramps to set speed; compressor spools up.
 ● Monitor oil inlet/outlet temperatures; adjust VFD-controlled fan if needed.

2. Data Logging
 ● HMI logs values every second: suction pressure, discharge pressure, reservoir pressure, oil temp, ambient conditions, flow rate.
 ● Alarm thresholds: oil temp > 130 °C (VFD shutdown), reservoir pressure > 14 bar (safety valve lifts).

3. Shutdown Sequence
 ● Reduce VFD speed gradually via HMI.
 ● Allow compressor to coast to idle under no-load.
 ● Open angle-seat valve to release reservoir pressure.
 ● Turn off VFD → PLC → main power.
 ● Drain residual oil via sampling point; collect for lab analysis.
 ● Log final test report (oil temps, pressures, run hours, energy consumption).

10. Materials of Construction & Safety Features
 ● Structural Steel: IS 2062 E 250 BR for skid, reservoir shell, support structures.
 ● Welding Standards: Qualified welders; Dye Penetrant Testing on critical joints.
 ● Coating: Powder coat on skid; primer + anticorrosive paint on reservoir.
 ● Safety:
   - Emergency pushbutton on VFD panel and DAQ cabinet.
   - Tower light (green = ready, yellow = running, red = fault).
   - Audible buzzer for alarms.
   - Over-temperature and over-pressure interlocks.
   - Password protection on operator interface.

11. Consumables & Maintenance Considerations
 ● Compressor Oil: Test grades (ISO VG 32, 46, 68, 100) supplied by BPCL.
 ● Filters:
   - Inline oil filters; replace every 200 hr.
   - Air dryer cartridges; change every 6 months or on moisture alarm.
 ● Coolant: Water/glycol mixture for oil cooler (if ambient > 35 °C).
 ● Recommended Spare Parts:
   - Pressure transmitter (one spare per range), temperature sensor (one spare).
   - V-belt set (if belt-driven); O-rings and gaskets for flanges.
   - Fuse/circuit breakers for VFD/PLC.
   - Tower light bulbs, HMI-PC backup storage.

12. Reporting & Deliverables
After each test run, deliverables include:
1. Oil Performance Report
 ● Oil inlet/outlet temperatures vs. time.
 ● Pressure curves (suction, discharge, reservoir).
 ● Flow rate vs. time.
 ● Observations (surges, pressure drops, abnormal temp rise).

2. Compressor Log
 ● Total run hours, VFD RPM profile, energy consumption (kWh).

3. Non-Conformance & Maintenance Log
 ● Sensor/calibration deviations.
 ● Leak or safety valve activations.
 ● Maintenance performed (filter changes, coupling checks).

4. Final Summary
 ● Conclusions on oil oxidation and suitability.
 ● Recommendations for next test cycle or oil change intervals.

In summary, this Compressor Test Rig is a fully integrated, CE-graded platform designed to:
 ● Run a 15 kW oil-flooded rotary screw compressor under controlled conditions.
 ● Cool and separate oil/air, then recirculate test oil for extended runs (≥ 4,000 hr).
 ● Log comprehensive data via PLC/DAQ and industrial PC HMI.
 ● Adhere to safety standards (pressure relief, interlocks, emergency stops).
 ● Provide with robust, repeatable testing of compressor lubricants.