Metal bellow seals in HF
Metal bellow seals in HF
(OP)
Dear all,
At this time we are upgrading some of our seal systems from single to dual seal, mainly because of security improvements.
In applications of Hydrofluoric acid (HF) we have received proposals that specify a dual Type B seals (metal bellow)with plan API 53B.
Our experience in this applications is seal Type A with API plan 32/53B.
Some of you have experience with metal bellow seals in HF?
Advantages and disadvantages?
Can we to use only the API 53B without the API 32 plan?
At this time we are upgrading some of our seal systems from single to dual seal, mainly because of security improvements.
In applications of Hydrofluoric acid (HF) we have received proposals that specify a dual Type B seals (metal bellow)with plan API 53B.
Our experience in this applications is seal Type A with API plan 32/53B.
Some of you have experience with metal bellow seals in HF?
Advantages and disadvantages?
Can we to use only the API 53B without the API 32 plan?





RE: Metal bellow seals in HF
What is the proposed barrier fluid?
RE: Metal bellow seals in HF
Thanks for your comments.
The proposed barrier fluid for the plan API 53B is isobutane, the same that we use for some other pumps with HF.
RE: Metal bellow seals in HF
RE: Metal bellow seals in HF
I noticed that nobody mentioned using a Plan 52 unpressurized seal. Good... Iron fluorides from the flare header tend to end up in the reservoir contaminating the buffer fluid and causing seal failures.
RE: Metal bellow seals in HF
RE: Metal bellow seals in HF
HF service requires either killed carbon steel or Monel metal to combat against corrosion. Edge welded metal bellows from any reputable seal manufacturer i.e. AES, Crane, Burgmann etc will not be available. Whilst you may use a plan 32, you risk assessment should cater for loosing the flush.
The most common selection is a Monel pusher either face to back or back to back reverse pressurised and a Plan 53B. Very reliable solution.
RE: Metal bellow seals in HF
Not sure where the above information about bellows was obtained from, but you can get edge welded metal bellows from most reputable seal manufacturers that will withstand HF service. However, they are not usually standard items and not typically recommended for reasons already stated; pusher seals are preferred.