Check valve series

[Overview]

Fluorine check valve is a kind of check valve lined with polytetrafluoroethylene (PTFE, commonly known as "fluoroplastic") or its derivative materials (such as FEP, PFA) inside the valve body (including key parts such as valve cavity, valve seat, valve core sealing surface, etc.). The core function is to use the medium's own pressure to automatically prevent fluid backflow, with It realizes corrosion resistance to strong corrosive media through fluoroplastic lining, which is widely used in chemical industry, pharmaceutical, metallurgy and other strong corrosion conditions.

Nominal pressure: PN0.6~PN2.5MPa

Nominal diameter: DN15~DN400

Applicable temperature: -196℃~260℃ (PTFE), -80℃~200℃ (FEP)

Applicable media: strong acid (hydrochloric acid, sulfuric acid, nitric acid), strong alkali (sodium hydroxide, potassium hydroxide), strong oxidizing agent (peroxide, sodium hypochlorite), organic solvent (methanol, ethanol, acetone)

Core advantages (strong corrosion resistance as the core)

1. Extreme corrosion resistance: The fluoroplastic lining is resistant to almost all common corrosive media, which solves the problem that ordinary metal check valves (such as stainless steel and cast iron) are easily corroded and have a short life in strong acid and strong alkali, and the service life can reach 3 to 5 times that of ordinary valves;

2. Reliable sealing: The fluoroplastic sealing surface has good elasticity and self-lubricating properties, which not only has a low sealing leakage rate, but also reduces the wear of the valve core and seat (especially suitable for media containing trace impurities);

3. Wide scope of application: temperature resistance covers extreme cold (-196℃) to medium and high temperature (260℃), which can be adapted to a variety of working conditions from low-temperature liquid corrosive media (such as liquid chlorine) to medium-temperature corrosive gases (such as sulfuric acid steam at 150℃);

4. Low maintenance cost: the fluoroplastic lining is wear-resistant and aging-resistant, and there is no need to replace the seal frequently under normal use; and the lining surface is smooth, the medium flow resistance is small, and it is not easy to scale (reduce the number of cleaning and maintenance).

Products and services that meet fluid control requirements

Each process, each facility, and each environmental constraint has its own special requirements. Therefore, Dongyan offers a comprehensive range of products covering different performance levels, pressures, different functions and different materials.

Detail

Key points of selection and maintenance

1. The key to model selection (to avoid corrosion resistance failure):

Matching media for lining materials: strong acid / high temperature choose PTFE, high viscosity / need welding choose PFA, low temperature / high toughness demand choose FEP;

The structural form matches the caliber and pressure: small caliber (DN≤80), low-pressure selection lifting type (good sealing), large caliber (DN≥100), medium and high pressure selection type (small circulation resistance);

Confirm the characteristics of the medium: If the medium contains particles, you need to choose the "fluorine-lined check valve with filter" (filter material 316L to prevent particles from entering the valve cavity); if the medium is prone to crystallization, you need to choose the "insulated jacket fluorine-lined check valve" (the jacket passes steam or hot water to prevent crystal blockage).

2. Maintenance points (extend the life of the lining):

Reverse installation is prohibited: It must be installed according to the arrow marking of the valve body. Reverse installation will cause the lining to be peeled off by reverse pressure and even the valve body will crack;

Avoid sudden cold and sudden heat: the temperature change rate is ≤5℃/min, to prevent the lining from being too large between the heat expansion and cold shrinkage of the substrate and peeling off;

Check the lining regularly: disassemble and check the lining every 6 to 12 months for bulging, cracks or peeling (especially near the flange sealing surface). If damage is found, the lining should be replaced in time (cannot only be repaired to avoid local corrosion diffusion);

Cleaning and lubrication: If the medium is prone to scaling, the valve cavity should be rinsed regularly with water or neutral solvent; the core stem (if any) of the lifting check valve should be applied to "fluoroplastic special grease" (such as perfluoropolyether grease every 3 months to avoid jamming.