Shimadzu FA-4A-M2 Flow Alarm

Shimadzu FA-4A-M2 Flow Alarm (NEW)

The Shimadzu FA-4A-M2 is an electromechanical flow alarm engineered specifically for critical fluid circuit supervision. Manufactured in Kyoto, Japan by Shimadzu Seisakusho Ltd., this instrument detects interruption, drop, or loss of lubrication oil and hydraulic fluid across primary machinery feed lines.

The unit operates on a magnetic displacement principle: line flow drives an internal mechanical float/vane against an adjustable counter-balance, magnetically triggering an isolated microswitch enclosure without direct fluid contact. This construction prevents fluid ingress into electrical housings, eliminating boundary leakage risks under marine engine room vibration, pressure spikes, and fluctuating viscosity.

Model Details:

• Manufacturer / Brand: Shimadzu Seisakusho Ltd. (Japan)
• Model: FA-4A-M2
• Part Number / MPN: FA-4A-M2 (Terminal Code: 4P-3.5)
• Equipment Classification: Mechanical Fluid Flow Monitoring Switch / Oil Flow Alarm

Technical Specifications

Terminal Allocation Breakdown

• Terminal 1 (COM): Common input line for power supply/signal loop.
• Terminal 2 (NC – Flow OK): Normally Closed contact under active positive flow; opens upon flow failure.
• Terminal 3 (NO – Flow Alarm): Normally Open contact under active flow; completes the circuit to trip annunciator buzzers, automated shutdown relays, or central alarm systems (AMS) upon flow stoppage.
• Terminal 4 (GND / Shield): Dedicated casing ground connection for earthing and electrical noise suppression.

Key Features

1. Magnetic Coupling Isolation: Isolates the internal fluid passage from the electrical microswitch housing, eliminating moving mechanical seals and preventing fluid leakage into wiring compartments.
2. Heavy-Duty 600V / 20A Switching Core: Capable of driving direct industrial trip coils and secondary contactors without interposing buffer relays.
3. Viscosity-Tolerant Float Geometry: Engineered to resist false alarms caused by transient changes in oil viscosity during cold engine start-ups and bunkering transfers.
4. Vibration-Damped Switching Mechanism: High-shock microswitch internals rated for continuous low-frequency structural vibration typical of low-speed, two-stroke marine propulsion engines.
5. Non-Corrosive Marine Construction: Finished with an anti-corrosion industrial finish suitable for harsh, salt-laden marine engine room environments.

Applications

• Main Marine Engine Lubrication: Monitoring cylinder oil feeds, piston cooling circuits, and crosshead bearing oil manifolds on MAN B&W, WinGD, and Sulzer engines.
• Auxiliary Diesel Generators: Continuous flow monitoring on Yanmar, Daihatsu, and Wärtsilä generator sets.
• Marine Reduction Gears & Stern Tube Systems: Interlocking lubrication supply lines on shaft line bearings and reverse reduction gearboxes.
• Centrifugal Oil Separators: Safeguarding sealing water, oil supply, and discharge loops on Alfa Laval, Westfalia, and Mitsubishi purifiers.
• Industrial Hydraulics & Power Plants: Standby lube pump trip initiation and dry-run safety lockouts in turbine plants and heavy presses.

Frequently Asked Questions

Can the Shimadzu FA-4A-M2 be used with high-viscosity heavy fuel oil (HFO)?

The unit is optimized for medium and high-grade mineral oils, lubricating oils, and light marine diesel fuels. While HFO can flow through the unit, fuel with high asphalt content and operating temperatures exceeding 90°C can cause sludge accumulation around the internal float mechanism, requiring frequent manual flushing.

How do I adjust the flow alarm trigger point?

Trip point adjustment is performed via the internal mechanical tensioner accessible under the protective switch cover. Loosen the setpoint locknut, adjust the calibrating screw to the desired threshold against your line flow meter, and re-torque the locknut to prevent drift caused by vessel vibration.

Is the electrical microswitch compartment isolated from pipeline fluid pressure?

Yes. The FA-4A-M2 utilizes an indirect magnetic coupling mechanism. The internal fluid chamber is hermetically sealed from the electrical terminal housing, preventing fluid ingress even if system pressures fluctuate up to 1.0 MPa (10 bar).

Can this unit wire directly to PLC analog I/O modules?

No. The FA-4A-M2 is a discrete electromechanical switch outputting dry contacts (NO/NC), not a 4–20 mA or 0–10V analog transmitter. Connect the contacts directly to digital PLC inputs (DI) or hardwired relay safety interlocks.