Compressor Test Rig, closed-loop to 12.5 bar.

Product overview

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

• 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.

Detailed technical specifications

Detailed hydraulic circuit

A closed-loop oil circuit passes as follows:

• Oil injection: oil from tank ("cold oil") is pumped into compressor bearings.
• Discharge separation: mixed oil + air enters the air/oil separator; oil drains back to tank; air passes through the air cooler.
• Oil cooling: separated oil flows through an oil cooler (temperature transmitters 6.3/6.4).
• Flow meter (7.0): measures oil flow (0–150 LPM).
• Sampling point: allows manual oil sampling for lab analysis.
• Safety valve (8.0): protects circuit from overpressure beyond 14 bar.
• Oil tank (9.0): 500 L capacity; equipped with level indicators, drain, and inspection ports.
• Return to compressor: oil recirculates to compressor's injection port (pressure transmitter 5.1 reads 0–16 bar gauge).

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 · 13.0 = optional instrumentation (e.g. dew-point sensor).

Mechanical and structural components

• Base skid & frame: fabricated from ISMC-100 channels (legs) and 10 mm thick MS base plate (IS 2066), welded per approved drawings, powder-coated. Lifting hooks (16 mm thick MS) at four corners, rated for safe jack and crane handling.
• Air reservoir & manifold: shell and dish ends in IS 2062 E 250 BR, ellipsoidal ends, hydro-tested to 15 bar; manifold blocks machined from MS, dye-penetrant tested; painted in primer + topcoat.
• Piping & fittings: high-pressure rated tubes (SS/PK) connecting compressor, cooler, reservoir, and valves, all joints leak-tested at 18 bar; auto-drain and air-operated angle-seat valves (Parker/Festo, ½″ BSPM).
• Cooling package: oil and air coolers sized to maintain oil ≤ 130 °C, with VFD-controlled fan/motor assembly for variable cooling based on discharge temperature.
• Instrumentation mounting: pressure gauges (Wika 233.50.100, 0–21 bar, 1% FS) on SS sockets (SA-105, 3000#) with isolation valves; flow meter (turbine, 1″ BSPF) downstream of oil cooler; temperature transmitters in 6 mm thermowells before/after oil cooler and at discharge.

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; START/STOP/RESET pushbuttons; emergency stop; 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; Ethernet link between PLC and industrial PC.
• HMI/industrial PC: 21″ TFT monitor with mimic diagram showing real-time tank level, oil temperature, pressures, and alarm status; logging of all parameters with 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.

Quality assurance & testing protocols

Factory Acceptance Test (FAT). Before dispatch, each rig undergoes hydraulic integrity leak testing at 18 bar, calibration verification for all transmitters from NABL-accredited labs, dimensional and visual inspection, air reservoir hydro-test and lifting-hook checks, and a full safety/interlock functional test — VFD ramp-up, oil cooling performance (40–84 °C inlet/outlet range, ≤ 130 °C cutoff), and pressure logging with confirmation of reservoir drain at 12.5 bar and relief at 14 bar.

Site Acceptance Test (SAT). After installation, mechanical and electrical hookup are verified, followed by a supervised full-load run for 4,000 hr (minimum expected compressor reliability), with handover of user/maintenance manuals, complete technical drawings, compressor test certificate, warranty certificate, and operator training by Neometrix service engineers.

Operational workflow

• Start-up: verify oil level, close reservoir drain valve, power up VFD and PLC/HMI, press START on HMI to ramp the VFD and spool up the compressor, and monitor oil inlet/outlet temperatures.
• Data logging: HMI logs suction/discharge/reservoir pressure, oil temperature, ambient conditions, and flow rate every second, with alarms at oil temp > 130 °C and reservoir pressure > 14 bar.
• Shutdown: reduce VFD speed gradually, allow the compressor to coast to idle, release reservoir pressure via the angle-seat valve, power down VFD/PLC/main power, and drain residual oil for lab analysis.

Materials of construction & safety features

• Structural steel: IS 2062 E 250 BR for skid, reservoir shell, and support structures, with qualified-welder joints and dye-penetrant testing on critical welds.
• Coating: powder coat on skid; primer + anticorrosive paint on reservoir.
• Safety: emergency pushbuttons on VFD panel and DAQ cabinet, tower light, audible alarm buzzer, over-temperature and over-pressure interlocks, and password-protected operator interface.

Consumables & maintenance considerations

• Compressor oil: test grades ISO VG 32, 46, 68, 100.
• Filters: inline oil filters replaced every 200 hr; air dryer cartridges changed every 6 months or on moisture alarm.
• Recommended spares: spare pressure/temperature transmitters, V-belt set, O-rings and gaskets, VFD/PLC fuses and circuit breakers, tower light bulbs, and HMI-PC backup storage.

Reporting & deliverables

Each test run delivers an oil performance report (temperature and pressure curves, flow rate vs. time, and abnormal-event observations), a compressor log (run hours, VFD RPM profile, energy consumption), a non-conformance and maintenance log, and a final summary with conclusions on oil oxidation and recommendations for the next test cycle.

Conclusion

In summary, the 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 for extended runs (≥ 4,000 hr), log comprehensive data via PLC/DAQ and industrial PC HMI, adhere to safety standards, and provide robust, repeatable testing of compressor lubricants.