Mark708 MAX Series
Maximum Inlet Pressure Diaphragm Control Valve
The Mark 708 MAX is designed specifically for fractional flow control — situations where you need tight, precise regulation at relatively low flow rates. The key differentiator over standard control valves is the rolling diaphragm, which keeps the effective actuator area constant throughout the entire stroke, resulting in a truly linear response to input signal changes rather than the drift you'd see with a flat diaphragm.
The "MAX" designation refers to the expanded pressure rating — up to 1,000 psi inlet pressure in carbon or stainless steel bodies, which is significantly higher than typical diaphragm valves and opens it up for high-pressure process applications.
On the applications side, the spec sheet calls out pilot plants, test stands, R&D, dosing, injection, and venting as primary use cases. The combination of high inlet pressure tolerance, exotic alloy trim options (Hastelloy, Monel, Titanium, Stellite), and an oxygen-clean option also makes it well-suited for chemical processing, oil & gas, and pharmaceutical/biotech environments.
Applications & Industries
- Pilot plants & R&D
- Dosing & Injection
- Venting Applications
- Chemical Processing
- Pharma & Biotech
- Oil & Gas
- Rolling diaphragm design ensures that the effective diaphragm area remains relatively constant, regardless of valve stem position
- Spring-loaded TFE-Chevron packing maintains a proper compression while minimizing excessive friction
- Bolted body/bonnet connection
- Guide trim – extended orifice and plug guiding are standard and offers improved shutoff and accuracy equivalent to heavy duty trim options of competitors
- Quick change trim
- Size: 1″ (DN25)
- Body Materials: B61 Bronze, WCB Carbon Steel, CF8M Stainless Steel
- Bonnet Materials: CF8M Stainless Steel
- Body Seals: Teflon Gasket
- Soft Seat: Peek, available for 6.5 Cv
- End Connections: FNPT standard, others available
- Flow Capacity: 6.5 Cv, 10 Cv
- Maximum Operating Pressure (FNPT): up to 500 psi (BR) or 1000 psi (CS/S6) max inlet @ 100°F
- Pressure @ Maximum Operating Temperature (FNPT): 350 psi max inlet @ 450°F (BR), 1000 psi max inlet @ 450°F (CS), 990 psi max inlet @ 450°F (CS)
Shutoff: Class IV hard seats, Class VI soft seats
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Mark 708 Series
Precision Control, Fractional Flow Control Valve
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