Longfor Enterprises Inc.

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Welcome to Longfor Enterprises Inc.

Longfor Enterprises Inc. offers gas sampling bags of various materials combined renovated, patented valves for collecting a wide range of gas and aqueous samples. We also carry PTFE lab ware.

our line of products includes:


FEP Bags;

PVDF Bags;


EVOH bags;

Fluolar bags;

DEVEX Foil Bags;

PTFE Labware.

Polyfluoro film has superb chemical inertness, ultra low adsorption and ultra low permeation. Polyfluoro film gas sample bags can handle and store various highly corrosive and highly active gaseous and liquid samples. They are widely used in petrochemical industry and environmental protection areas.

Currently there are three most popular types of poly fluoro films that are used to manufacture gas sample bags. Polyvinyl fluoride (PVF, such as Tedlar) film has a long history in making gas sample bags. Polyvinylidene fluoride (PVDF) is another type of poly fluoro film. The third type of poly fluoro film is called fluorinated ethylene propylene copolymer (FEP), such as Teflon FEP made by DuPont Co. The mechanical strength and chemical inertness of PVF film are slightly lower than that of PVDF films. Both PVF and PVDF have similar properties of gas adsorption and permeability. FEP film has superb chemical inertness, ultra low gas adsorption and low permeability. FLUODE gas sampling bags are excellent substitute of PVDF bags. DEVEX Foil gas sampling bags have excellent mechanical strength, low permeability and good chemical inertness. DEVEX and DEVEX Foil gas sampling bags can handle a wide range of non corrosive, weak corrosive and light sensitive gas samples.

Most valves used gas sampling bags have an O-ring inside to prevent leakage. The O-ring is the one source of contamination and is not ideal for VOC analysis. Some valves use silicone grease to improve the sealing property. Silicone grease may increase background level when analyzing low level gas samples. In order to overcome the above-mentioned drawbacks of valves, our team redesigned the valves. The designs of valves are patented or patent-pending in different countries around the world. BY using precision moulding technology, our valves are manufactured with high precision and convenient to use. To avoid cross-contamination, there is no any rubber seal to contact with gas sample; and the authenticity and integrity of the sample are protected during storage, especially suitable for extra low level (ppb) gas analysis. There is no silicone grease used in the fittings therefore silicone background is avoided in GC-MS analysis

Our films used to make gas sample bags are supplied by a renowned world-class manufacturer. We have strict total quality control systems in place to assure that all products are high quality.