Fractional Flow Control Valves
Pneumatic and Electrically Actuated Control Valves for Precision Micro-Flow Applications
LowFlow fractional flow control valves deliver accurate, repeatable control at very low flow rates. With pneumatic or electric actuation in line sizes 1/4" to 1" (DN8–DN25) , the Mark 708 family covers Cv values from 0.00001 to 4.0. With Cryogenic and high-pressure options, LowFlow valves can handle applications at temperatures ranging from -425°F (-254°C) to above 1000°F (538°C) and inlet pressures up to 8000 psi (552 bar). They are built for pilot plants, R&D facilities, OEM equipment, dosing systems, and analytical instrumentation. Contact us for assistance in finding the right one for your process.
Mark 708 Series ⟶
Precision Control, Fractional Flow Control Valve
Mark708 MAX Series ⟶
Maximum Inlet Pressure Diaphragm Control Valve
Mark 708SH Series ⟶
Short Pattern Fractional Flow Control Valve
Mark 708BS Series ⟶
Bellow Stem Seals Fractional Flow Control Valves
Mark 708CR Series ⟶
Extended Bonnet Fractional Flow Control Valve
Mark 708DP Series ⟶
Double Packing Fractional Flow Control Valve
Mark 708HP Series ⟶
High Pressure Control Valve
Mark 708HPA Series ⟶
High Pressure Angle Control Valve
Mark 708HT Series ⟶
Finned Bonnet Fractional Flow Control Valve
Mark 708MV Series ⟶
Motor Control Valve; 1/4″ – 3/4″ (DN8 – DN20); Globe - Class IV or VI
Mark 709 Series ⟶
Three Way Control Valve
8000 Series ⟶
Heavy Duty Control Valve
8000BS Series ⟶
Bellows Stem Seals, Control Valve
8000CR Series ⟶
Cryogenic, Control Valve
8000T Series ⟶
Three Way Control Valve
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Engineered for Precision Micro-Flow Control
In fractional flow service, even small deviations in valve response can compromise process integrity, product quality, or safety, so accuracy and repeatability come first. LowFlow valves combine rolling diaphragm actuation, guided trim, and quick-change trim for consistent performance in liquid, gas, and steam service across a wide range of temperatures and pressures.
Key Features
- Cv range: 00001 to 4.0 (Kv: 0.000009 to 3.4)
- Rolling diaphragm actuator: consistent stroke force, low hysteresis
- Quick-change trim standard at Cv ≥ 0.05 in-line trim change, no special tools
- Bolted body and bonnet: valve stays in line during trim changes and maintenance
- Spring-loaded TFE/Chevron packing: reliable stem seal across a broad temperature range
- Guided trim standard for precise, repeatable positioning
- Globe seat: ANSI Class IV or Class VI shutoff
- Pneumatic actuation: 3–15 psi or 6–30 psi; split ranges available with positioner
- Electric/motor actuation available (Mark 708MV Series)
- Optional side – or top-mounted positioner
- Body materials: Carbon Steel, 316/316L SS, Hastelloy C, Monel, Alloy 20
- End connections: NPT, BSPT, BSPP, Socket Weld, Integral Tube, Welded Flange
- Certifications: CRN (Canadian Registration) and ATEX (reference individual products for certifications)
Available Series
| Model | Key Feature | Typical Applications |
|---|---|---|
| Mark 708 | Standard precision model | Pilot plants, R&D, OEM equipment, dosing, and injection systems |
| Mark 708MAX | Maximum inlet pressure diaphragm | High inlet pressure process systems |
| Mark 708SH | Short-pattern design | Space-constrained installations |
| Mark 708BS | Bellows stem seal | Fugitive emissions control, hazardous service, and test stands |
| Mark 708CR | Cryogenic extended bonnet (-425°F) | Liquid CO₂, hydrogen, and nitrogen applications |
| Mark 708DP | Double packing | Government projects, hazardous service, and pilot plants |
| Mark 708HP | High-pressure design | Hydrocarbon processing, chemical processing, and offshore injection |
| Mark 708HPA | High-pressure angle-body design | High-pressure industrial systems and offshore injection |
| Mark 708MV | Motor (electric) actuated | Skid builders, research laboratories, and dosing systems |
| Mark 709 | Three-way configuration | Mixing, diverting, and bypass applications |
| 8000 Series | Heavy-duty construction | Corrosive and harsh environments, dosing, injection, and venting |
| 8000BS | Heavy-duty bellows stem seal | Hazardous service, fugitive emissions control, and industrial plants |
| 8000CR | Heavy-duty cryogenic design | Liquefied gases, liquid CO₂, and low-temperature service |
| 8000T | Heavy-duty three-way configuration | High-capacity blending, bypass systems, and heat exchangers |
Applications and Industries Served
| Industry | Application |
|---|---|
| Chemical Processing, Refining & Petrochemical | Pilot plants and process scale-up |
| Pharmaceutical & Biotech, Laboratories | R&D test stands and laboratory systems |
| Industrial Manufacturing | OEM analyzers, dosing systems, and custom equipment |
| Oil & Gas, Chemical Processing | Chemical injection and additive dosing |
| Power Generation, Semiconductor & Electronics | Analytical instrumentation and sampling systems |
| Oil & Gas, Aerospace & Defense | Cryogenic service applications — Mark 708CR, down to -425°F (-254°C) |
| Refining & Petrochemical, Power Generation | High-temperature service above 1000°F (538°C) |
| Food & Beverage, Supercritical Extraction | Supercritical CO₂ processing and extraction |
| Aerospace & Defense | Hydrogen fuel cell and propulsion test stands |
Why Choose LowFlow
Fractional flow control is our specialty it’s all LowFlow does. Every model is engineered around micro-flow performance.
- Purpose-built Cv range from 0.00001 to 4.0 in a compact 1/4″–3/4″ body
- Fifteen standard series spanning standard, cryogenic, high-temp, high-pressure, bellows seal, double packing, three-way, and heavy-duty service
- In-line trim change without tools or process shutdown, reducing maintenance downtime
- Exotic alloy bodies for corrosive or high-purity process fluids
- ATEX and CRN certified
- Part of Richards Industrials alongside Jordan Valve, Steriflow, Marwin Valve, Bestobell Steam Traps, Equilibar, and other precision flow control brands
Request Technical Assistance
Our engineering team provides valve sizing, Cv selection, material recommendations, and OEM integration support for fractional flow applications.
Contact us to discuss your requirements.