PCTFE Gasket,PCTFE Washer for LNG Cryogenic Sealing
PCTFE is well suited for cryogenic parts such as ball valve seats & seals.
We can supply the PCTFE washer and PCTFE parts according to the drawings
Polychlorotrifluoroethylene (PCTFE or PTFCE),PCTFE (originally known as Kel-F) is a thermoplastic chlorofluoropolymer with the molecular formula (CF2CClF)n, where n is the number of monomer units in the polymer molecule. It is similar to polytetrafluoroethene (PTFE), except that it is a homopolymer of the monomer chlorotrifluoroethylene (CTFE) instead of tetrafluoroethene. It has the lowest water vapor transmission rate of any plastic.
PCTFE is a kind of perfect sealing material under low temperature, high vacuum system and high pressure working conditions. It has excellent rigidity, low temperature resistance, cryogenic fluid resistance, and airflowresistance.
In terms of cryogenic sealing, two main polymers used on the market are : PCTFE – polychlorotrifluoroethylene – and PTFE – polytetrafluoroethylene – and more specifically MPTFE, i.e. modified PTFE (TFM® or NXT®).
These polymers are very much in demand, particularly in cryogenic sealing systems, thanks to their properties at very low temperatures. They offer better ductility and also important load-bearing characteristics in environments where all other materials are very brittle, including metals.
In terms of the choice of sealing material for cryogenic valves, many characteristics are required, namely :
- rigidity characteristics adapted to obtain effective sealing at very low and ambient temperatures,
- Fast recovery after load removal,
- high wear resistance and low friction,
- Toughness and strength depending on the application,
- Low thermal expansion to avoid thermal mismatch with adjacent metal components,
- high thermal conductivity to allow rapid temperature equalization with all surrounding components.
- the widest possible operating range of temperature and pressure.
LNG – Liquefied Natural Gas – is a mixture of hydrocarbons composed mainly of methane, but with varying levels of ethane, propane, butane and other gases present in natural gas. In general, LNG has a boiling temperature between -166°C and -57°C at atmospheric pressure.
