ASML 879-0054-002 PROTEUS 150SST Fluid Flow Switch

The ASML 879-0054-002 is a PROTEUS 150SST fluid flow switch, also referenced as 858-8140-003 and 156282. This device is used to monitor the flow of cooling water or other fluids in ASML lithography systems, providing a safety interlock if flow drops below a preset threshold, preventing overheating of lasers and optics.

Technical Specifications

• Part Number: 879-0054-002

• Model: PROTEUS 150SST

• Alternative References: 858-8140-003, 156282

• Fluid Type: Water, deionized water, ethylene glycol mixtures

• Flow Range: 1–30 L/min (adjustable set point)

• Set Point Accuracy: ±5% of reading

• Hysteresis: 10% of set point

• Contact Type: SPDT relay, 24 V DC / 1 A, or 120 V AC / 0.5 A

• Process Connection: 3/4 inch NPT female

• Material: 316L stainless steel body, PTFE seals

• Temperature Range: 5°C–80°C

• Pressure Rating: 10 bar max

Functional Description

The flow switch operates on the paddle-type principle: a spring-loaded paddle is deflected by the fluid flow; when flow exceeds the set point, the paddle actuates a microswitch. The set point is adjustable via a screw on the top of the housing. The switch provides a normally open and normally closed contact, allowing both alarm and safety shutdown functions.

Installation and Piping

Install the flow switch in a horizontal pipe section with at least 10 pipe diameters of straight run upstream. Ensure the arrow on the body points in the direction of flow. Use thread sealant suitable for the fluid. Connect the electrical wires to the terminal block inside the housing; use a cable gland for strain relief. The switch must be grounded to prevent electrical noise.

Calibration and Adjustment

To set the flow switch, run the system at the desired minimum flow and adjust the set screw until the switch just changes state. Confirm by reducing the flow slightly; the switch should return to its original state with the appropriate hysteresis. A flow meter should be used during calibration.

Maintenance and Troubleshooting

Inspect the paddle for wear or fouling annually. Clean the paddle with a soft brush if deposits are present. Check the electrical contacts for oxidation. If the switch fails to trip, check for debris blocking the paddle or a broken spring. The MTBF is approximately 50,000 cycles.

Integration with ASML Systems

This flow switch is commonly used in the cooling circuits of lasers, lenses, and power supplies in PAS 5000/2500 and TWINSCAN systems. It interfaces with the system’s alarm logic, triggering a shutdown if coolant flow is insufficient.

Environmental and Safety

RoHS compliant. The switch is designed for use with non-hazardous fluids. It meets IP65 for dust and water ingress. Operating temperature range as specified.

Technical Support

ASML provides installation instructions, calibration procedures, and a troubleshooting guide. Replacement paddles and O-rings are available.

Conclusion

The ASML 879-0054-002 PROTEUS 150SST Flow Switch is a reliable and adjustable device for monitoring critical cooling flows, helping to protect expensive optical and electronic components from thermal damage.