Selection Criteria And Operating Guidelines For Electric Fluorine-lined Gate Valves

The lined globe valve is designed for throttling, not just isolation. For corrosive media lines needing precise flow adjustment, this valve type is correct. Gate valves lack throttling capability; butterfly valves offer limited rangeability. A lined globe valve provides control precision with a fluoropolymer liner that resists corrosion and contamination. The selection decision depends on whether the process requires regulation or simple shut-off.

Globe vs. Gate: Different Functions

Internal construction determines primary function.

○ Globe valve – Disc moves perpendicular to seat, creating a variable orifice. This provides near‑linear flow characteristic for throttling. Fluid changes direction twice, causing higher pressure drop but better control.

○ Gate valve – Gate moves parallel to seat, offering full‑bore opening when fully open. It provides minimal pressure drop but poor throttling. Using a gate valve for flow control erodes seat and disc.

For corrosive media, a lined globe valve combines throttling with a fluoropolymer liner protecting all wetted surfaces, enabling precise flow adjustment without metal corrosion or contamination.

Liner Material Selection for Throttling Service

Choose liner based on fluid composition and temperature.

● PTFE lined globe valve – Polytetrafluoroethylene resists most acids, bases, and solvents up to 150°C. A ptfe lined globe valve handles hydrochloric acid, sulfuric acid, and organics. Low friction reduces wear during continuous throttling.

● PFA lined globe valve – Perfluoroalkoxy offers similar resistance with lower permeation and higher temperature (180°C). A pfa lined globe valve suits wet chlorine, bromine, and halogens. The denser PFA surface blocks molecular penetration, extending service life. Multiple pfa lined globe valves are common in chlorine feed systems where reliability is paramount.

● Lined globe valve selection – Choice between PTFE and PFA depends on temperature, permeation risk, and cycling frequency. For high‑purity applications, PFA minimizes ion leaching and particle generation.

Electric Actuation for Precise Control

Motorized actuation provides accurate positioning and remote operation.

◆ Electric actuator – Converts electrical signal (4‑20mA or 0‑10V) into mechanical rotation. Drives stem up/down, positioning disc with high repeatability. Enables PLC or DCS integration.

◆ Fail‑safe options – Some include battery backup or spring‑return for fail‑closed/open during power loss.

◆ Modulating vs. on‑off – For throttling, select modulating actuator with continuous positioning. On‑off suits isolation only.

Flow Characteristics and Rangeability

▪ Linear characteristic – Flow changes proportionally with stem travel. Suits constant pressure drop systems.

▪ Equal‑percentage – Flow changes by percentage of current flow. Suits varying pressure drop, providing stable control across operating range.

▪ Rangeability – Ratio of maximum to minimum controllable flow. Lined globe valves offer 30:1 to 50:1, superior to butterfly valves (10:1 to 20:1), enabling finer control at low flows.

Selection Criteria Summary

Installation and Operational Guidance

➤ Flow direction – Install flow‑to‑open (under disc) for better shutoff and reduced seat wear; also smooths throttling.

➤ Avoid cavitation – For high pressure drops, consider multi‑stage or anti‑cavitation trims to prevent liner damage.

➤ Actuator sizing – Select torque based on max differential pressure at closed position. Oversizing prevents stalling; undersizing causes positioning errors.

➤ Periodic calibration – Check position feedback and travel limits during maintenance to ensure accurate control and prevent over‑travel.

Temperature and Pressure Parameters

► PTFE liners – max 150°C (302°F)
► PFA liners – max 180°C (356°F)
► Pressure rating – Class 150 (PN10/PN16)
► Shell test – 1.5 × nominal rating
► Seat leakage – ANSI/FCI 70‑2 Class IV or VI (depends on liner)

Final Selection Logic

For corrosive media lines requiring precise flow control:

1. Define fluid composition, temperature, and flow range.

2. Determine if throttling or isolation is primary.

3. Select PTFE for general acids; PFA for halogens and permeation‑sensitive services.

4. Choose electric actuation for automated control; specify modulating for continuous throttling.

5. Verify flow characteristic (linear or equal‑percentage) matches process dynamics.

6. Confirm actuator sizing and fail‑safe requirements.

This structured approach ensures a lined globe valve delivers precise, corrosion‑free flow control in demanding chemical processes. The fluoropolymer liner and electric actuation provide the accuracy and reliability required for critical applications.

FVF Electric PTFE Lined Globe Valve

• FVF Lined globe valve is fully lined with fluorine materials.It has good anti-corrosive function and it is a better choice to shut-off in corrove pipeline.
• Globe valve refers to the valve with disc driven by stem along the central axis to make lifting movement, is a common block valve,used to connect or throttle medium.
• It has the advantage of compact structure, flexible on-off, strong corrosion resistance, trip shorted and widely applicated in chemical, petroleum, pharmaceutical, food, metallurgy, paper, hydropower, environment protection etc.
• They can be equipped with handwheels or can be actuated with electric or pneumatic actuators. A full range of accessory items are available including limit switches, solenoid valves, positioners and manual override devices.

Product Parameter

Materials of Main Parts

Technical Specification