ZFV provide both API 609 A series butterfly valve and API 609 B series butterfly valve. Generally the API 609 A series butterfly valve is concentric design, with soft seat material . Mainly soft material include NBR, EPDM, Viton, PTFE etc.. Soft seat butterfly valve is excellent in seat sealing performance, which means 0-leakage in corrosive servise using .
The limitation of soft seat butterfly valve is temperature or some special service, normally this kind of valve is not used in particle servise using, also not used in high temperature.
Below is a general explanation for using temperature for soft seat material :
In case the valve have to be used in partical service and high temperature, we suggest API 609 B series metal seated butterfly valve, with eccentric design ( which is also named offset type butterfly valve: double offset type valve and triple offset type butterfly valve )
Or you may contact us by email or telephone mentioned on our website if any question, our engineer shall provide professional suggestion for your case.
Zhejiang Zhengfeng valve