Fluorine-lined gate valve is a type of valve with a fluoroplastic inner lining, specifically designed for highly corrosive media. Its core structure and application characteristics are as follows:

?I. Definition and Structure?

?Opening and Closing Structure?

The opening and closing element of a fluorine-lined gate valve is the gate plate, whose movement direction is perpendicular to the fluid flow. It only supports fully open or fully closed operations and cannot be used for flow regulation?1. The sealing surface of the gate plate is usually wedge-shaped, with the wedge angle adjusted according to valve parameters (e.g., 2°52' at room temperature). Gate plates are divided into integral rigid gate plates and slightly deformable elastic gate plates; the latter can compensate for machining deviations to improve sealing performance?15.

?Lining Material?

The inner wall of the valve body is lined with fluoroplastics such as polytetrafluoroethylene (FEP/F46) and polychlorotrifluoroethylene (PCTFE/F3). These materials, with their high chemical inertness, resist corrosion from strong acids (e.g., sulfuric acid, hydrochloric acid, aqua regia), strong alkalis, and organic solvents?23.

?II. Classification and Working Principle?

?Structural Classification?

?Sealing Surface Type?: Classified into wedge-type gate plates (single gate plate, double gate plate, elastic gate plate) and parallel gate plate type (single gate plate, double gate plate)?15.

?Stem Design?: Rising-stem gate valve (stem movement visible during lifting/lowering) and non-rising-stem gate valve (stem rotation not visible)?5.

?Sealing Mechanism?

When closing, the gate plate is pressed against the valve seat by the medium pressure to achieve self-sealing; some models require external force for forced sealing. The rising-stem structure converts the handwheel rotation into the linear movement of the gate plate through trapezoidal threads?15.

?III. Performance Advantages?

?Corrosion Resistance?

The fluoroplastic lining can withstand most chemical media, including concentrated acids, strong oxidants, and organic solvents, with a wide applicable pH range?23.

?Temperature Adaptability?

The applicable temperature range is generally -50℃～150℃; some materials (e.g., PTFE) can withstand high temperatures of up to 260℃ for short periods?34.

?Sealing Performance?

The soft-sealing structure combined with precision machining achieves low leakage or even zero leakage, making it particularly suitable for harsh working conditions?45.

?IV. Application Scenarios?

?Industrial Fields?: Used for full-open/full-close control of corrosive media in industries such as petrochemicals, pharmaceuticals, dyes, and acid production?13.

?Medium Types?: Sulfuric acid, hydrofluoric acid, chlor-alkali, organic solvents, etc.?24.

?V. Installation and Maintenance?

?Installation Specifications?

Double-gate plate valves must be installed vertically (stem vertical, handwheel at the top)?1;

For models with a bypass valve, the bypass valve must be opened first to balance the pressure difference and reduce the opening/closing torque?15.

?Operation Precautions?

The fully open position is marked by the top of the stem; usually, it is necessary to turn back 1/2～1 turn to prevent jamming caused by temperature changes?5;

Lifting the valve using the handwheel or transmission mechanism is prohibited, and collision should be avoided?1.

?Maintenance Requirements?

Valves that are operated frequently need to be lubricated at least once a month?1;

Regularly check the integrity of the lining layer to prevent medium penetration from causing corrosion of the metal shell?34.

?VI. Selection Reference?

?Model Example?: For example, Model Z41F46 has a nominal pressure of ≤2.5MPa and an applicable temperature range of -29℃～180℃?5.

?Material Selection?: Select FEP (resistant to organic solvents) or PCTFE (resistant to oxidizing acids) based on the characteristics of the medium?23.

With the above design, fluorine-lined gate valves combine the strength of the metal structure with the chemical stability of fluoroplastics in highly corrosive environments, making them key control components for high-corrosion working conditions.