Flowserve Argus FK75M Floating Ball Valve ANSI 150/300

Flowserve Argus FK75M floating ball valve overview

The Flowserve Argus FK75M (written FK 75M on the datasheet) is a split-body floating ball valve for on-off service in ANSI Class 150 and Class 300 pipelines. It is designed to API 6D, ANSI B16.34 and BS 5351, uses a superfine-finished ball, an anti-blow-out stem and spring-loaded seats with cavity relief, and is fire safe to BS 6755 and API 607.

The manufacturer highlights a clear separation between sealing and bearing functions, which gives long life and low operating torque. The stem is supported in bearings so the stem seals are free of operating loads. This page describes the FK75M as a series: the final valve is defined by size, class, bore, body and ball materials and seat type. Seven Star LLC is an independent supplier in Muscat and supports Flowserve valve enquiries in Oman and the GCC.

FK75M technical specifications

The standard material combinations are listed in the table further down this page.

How the FK75M floating ball works

In a floating ball valve the ball is not fixed on trunnions; it is held between two seats and is pushed against the downstream seat by line pressure. The FK75M adds spring-loaded seats so that sealing is also available at low pressure, and a cavity-relief feature protects the valve against pressure built up by liquid trapped between the ball and body when the valve is closed.

The pad-mounted ball and the bearing-supported stem keep the sealing function away from the mechanical loads on the stem. The stem uses a double-seal system and the anti-blow-out design keeps the stem inside the body if the gland is lost. An anti-static device maintains electrical continuity between ball, stem and body, which is important in hydrocarbon service.

Where the FK75M fits in the Flowserve valve range

The FK75M handles the mid-size, moderate-pressure end of Argus on-off ball valves. Sizes or classes outside the datasheet list need a different valve series, which we can help identify. For automated lines the FK75M is typically combined with a pneumatic or electric actuator on the ISO 5211 plate and with limit switches. Control duties requiring throttling are normally handled by control valve ranges rather than floating ball valves.

FK75M selection and ordering checklist

• Nominal size DN and ANSI class (150 or 300), and full or reduced bore
• Line fluid, temperature range, maximum pressure and differential pressure
• Body material: low-temperature carbon steel or stainless steel
• Ball and stem material, matched to corrosion and erosion risk
• Seat: PTFE for general use, hardfaced metal seats for abrasive or high-temperature duty
• Seal material: PTFE, FPM or MFQ
• Fugitive emission or fire-safe certification required
• End connection, face-to-face and flange standard
• Operation: lever, gearbox or actuator with ISO 5211 size
• Accessories: limit switches, locking device, extended wrench, stem extension, steam jacket, drain and vent connections

Installation, commissioning and maintenance

Check the installation orientation against the manufacturer instructions for the valve, and flush the line before first operation to avoid scoring the ball or seats. Support the pipe so the valve body is not loaded by pipe strain.

For commissioning, cycle the valve several times, check the gland for leakage and confirm limit-switch positions. Standard maintenance covers stem seal adjustment, periodic cycling of rarely operated valves and checking the actuator linkage. The split-body construction allows seat and seal replacement, so seat kits and body seals are the spare parts to hold for critical lines.

Typical FK75M applications in Oman and the GCC

The combination of API 6D, fire-safe design and low-emission stem sealing makes the FK75M suitable for oil and gas pipelines, refinery and petrochemical process lines, fuel and utility headers and power plant services. Low-temperature carbon steel bodies are listed for colder duties, and stainless steel bodies for corrosive media. In Oman and the GCC, heat, dust and coastal humidity should be considered for actuator enclosure ratings, paint and external fasteners.

FK75M standard material combinations

The datasheet recommends these combinations as preferred for short delivery. Stem and body seals are PTFE with Celastic, and seat springs are stainless steel in all four.

Information to send with an FK75M RFQ

• Size, class, bore type and quantity
• Process fluid, pressure and temperature
• Body, ball and seat material or the standard material code
• Actuation type and signal or power supply
• Required certificates, fire-safe and emission test requirements
• End-user specification or tag list if available

Documents and quotation

A datasheet for the FK75M is attached on this page. Please send the size, class and material code you need so that we can confirm availability and arrange a quotation.

Seven Star LLC is an independent supplier and does not claim any official status with the manufacturer.