Flowserve Valtek MaxFlo 4 Eccentric Rotary Plug Control Valve

Overview

The Flowserve Valtek MaxFlo 4 is a high-performance eccentric rotary plug control valve designed for the process industry. It combines a large flow capacity, standard hardened trim and shaft blow-out protection in a compact rotary body, and it is available in sizes from 1 to 12 inch (DN 25 to 300), in ASME Class 150, 300 and 600 and in PN 10, 16, 25, 40 and 63. With a rangeability of up to 160:1, a temperature range of -50 °C to 400 °C and ANSI/FCI 70-2 Class IV or Class VI shutoff, the Valtek MaxFlo 4 covers a broad band of liquid, gas and steam control duties where a globe valve would be larger, heavier or more expensive.

Seven Star LLC supplies the Valtek MaxFlo 4 with its actuators and positioners to refineries, gas plants, petrochemical units, power stations and water facilities throughout the Sultanate of Oman and the GCC, with engineering support in Muscat. Our team works with process and instrument engineers on sizing inputs, trim selection and actuator choice, and coordinates complete valve assemblies for new projects and replacements in Muscat, Sohar, Duqm and Salalah.

Operating Principle of the Valtek MaxFlo 4

In the Valtek MaxFlo 4, a double-offset eccentric plug rotates into the seat at an angle that eliminates sliding over the seat surface. As soon as the shaft starts to turn, the hard stainless steel plug lifts off the seat, so no breakout torque is required and seat wear is kept low. Flowserve states that this reduces maintenance requirements and costs, and that a tight Class VI shutoff is easily obtained with the soft seat design. The shaft is connected to the plug through a polygon connection, which is stronger and more precise than a keyed or pinned joint, reduces backlash and withstands greater shock loads under torque reversal.

As general engineering background, eccentric rotary plug valves sit between globe and butterfly valves: they offer much of the control precision and shutoff of a globe valve, but with a straight-through rotary flow path that gives higher capacity per size and lower actuator thrust. Flowserve notes that the open flow path of the Valtek MaxFlo 4, without the shaft obstructing the flow, provides as much as 70 % more Cv than competing designs, which in many cases allows a smaller, more economical valve to be selected.

Engineering Design of the Valtek MaxFlo 4

Bodies are made in A216-WCC carbon steel or A351-CF8M stainless steel (1.0619 and 1.4408 for DIN), with flanged or wafer ends to ASME B16.5 raised face or RTJ, or EN 1092-1. Face-to-face options include the ISA 75.08.02 short pattern and an ISA 75.08.01 globe-length flanged body, which makes the Valtek MaxFlo 4 an easy drop-in replacement for an existing globe control valve. Plug and seat are available as standard, hardened or soft seat versions, and trims are offered in 100 % area and reduced sizes. The seat is shimless for simple assembly, the separate bonnet ensures positive anti-blowout and accommodates multiple packing options, and the flanged end post allows easy maintenance.

Packing choices include PTFE V-ring, braided PTFE, graphite, SureGuard XT, Garlock SVS, LATTYflon and LATTYgraf in single, twin, vacuum, live-loaded, fire-safe and O-ring arrangements, meeting TA-Luft, ISO 15848-1 and EPA requirements. An optional integral noise-reduction plate, fitted inside the body, reduces noise by 5 to 10 dBA on gas service without changing the valve length. Actuation is by the Flowserve NR diaphragm, VR piston or SuperNova rack and pinion actuator, with the Logix 420 digital positioner as standard and other Logix and XL-90 positioners as options.

Key Features of the Valtek MaxFlo 4

The Valtek MaxFlo 4 offers the following benefits in control valve service:

• Sizes 1 to 12 inch (DN 25 to 300), ASME Class 150 to 600 and PN 10 to 63.
• High flow capacity from an unobstructed flow path, allowing smaller valve sizes in many cases.
• Rangeability up to 160:1 for wide turndown control.
• Double-offset eccentric plug lifts off the seat immediately, with no breakout torque and low seat wear.
• Polygon shaft-to-plug connection for precise, backlash-free and shock-resistant control.
• Blow-out-proof shaft to ASME B16.34 as standard on every valve.
• Class IV metal-seat or Class VI soft-seat shutoff to ANSI/FCI 70-2.
• Globe-length body option and integral noise-reduction plate reducing noise by 5 to 10 dBA.

Industrial Applications

Flowserve designed the Valtek MaxFlo 4 as a general-purpose process control valve suitable for most applications in continuous process industries. In Oman and the GCC it is a practical choice for level, pressure and flow control loops in refineries and gas plants, steam and condensate control in utilities, slurry-tolerant and viscous liquid services in chemical units, and globe valve replacement projects where existing piping must be retained. Its compact rotary design also suits skid-mounted packages built by fabricators in Sohar, Rusayl and Duqm.

Seven Star LLC supplies the Valtek MaxFlo 4 as a complete assembly and can align it with other Flowserve products already installed, such as the Valtek Mark One globe control valve and the Logix 3800 digital positioner. Where electric actuation is preferred for associated isolation valves, the Limitorque MX multi-turn actuator is also available through our team.

Technical Specifications

The following data is taken from the Flowserve product brochure:

How to Order

To request a formal quotation for the Valtek MaxFlo 4, send Seven Star LLC your control valve data sheet or the fluid, flow range, pressures, temperature, line size, rating and required shutoff class. Our engineers in Muscat will coordinate sizing, trim and actuator selection, confirm delivery and support installation anywhere in Oman or the GCC. The Flowserve product brochure is available for download on this page.