Hydrofluoric Acid…

If you know what it is then it may seem like we are teaching you to “suck eggs” (in the words of our marketing people) but if you don’t you might be surprised at just how damaging this acid is.  Classed as a mild acid, Hydrofluoric Acid is highly toxic and highly corrosive; so corrosive in fact, that it dissolves glass, ceramics and metals so handling this fluid does present a series of challenges.

One of the problems presented is the toxicity of Hydrofluoric Acid….  Coverage the size of the palm of your hand is enough to kill you.  The burn isn’t instant, it develops over a number of hours and once it has got to that stage it is ordinarily too late.  Some of our customers who manufacture this acid equip all personnel with an antidote which is applied immediately after contamination because you will not have time to seek medical attention so a pump which does not leak is vital, and does not leak fluids or vapours is essential.  Magnetic drive pumps do not feature seals and do feature a zero-vapour loss design making them the ideal choice for fluids like this.

Secondly, the corrosive nature of Hydrofluoric Acid means it is not suitable for a metallic pump – not even the strong ones – Stainless steel, super duplex and even titanium are all completely ineffective and will lead to a catastrophic failure of the pump.

PVDF and ETFE however are extremely effective, the acid is not corrosive to plastics.  Polyvinylidene fluoride (PVDF) is known for its non-reactive properties and is used in applications which require the highest levels of purity whereas Ethylene tetrafluoroethylene (ETFE) is highly resistant to corrosion across a variety of temperatures.

So now we have established we need a magnetically driven pump that has been either wholly manufactured or lined in a polymer plastic – not necessarily a problem because we have these on the shelf in our Wellingborough workshop – but what about other equipment?

Where will you be mounting your pump?  On the ground? On a baseplate? Does it need to be raised? Is a traditional steel baseplate the right choice for an acid which is corrosive to metal?

By choosing a magnetic drive pump, you have already significantly reduced the risk of leakage and toxic vapours entering the atmosphere so you can be forgiven for thinking your choice of mounting the pump is not as important because your pump isn’t going to leak; but this doesn’t mean we shouldn’t think about what happens if there is a failure?

Obviously, the easy answer to the team here is to include a polymer concrete baseplate; these baseplates are still a relatively new addition to the UK market so not many people talk about them.  Baseplates are manufactured with a silicon dioxide ceramic, quarts aggregate and resin blend which gives them a tight finish, exceptional vibration damping and enviable resistance to corrosion.  The silicon quartz ceramic is not the same as standard ceramics or glass so it is not prone to the same weaknesses making it the right choice for Hydrofluoric Acid applications.  Admittedly, polymer concrete baseplates wouldn’t stand up to full immersion because this acid is particularly toxic and corrosive, but if that happens then your fluid handling solutions will most definitely not be your primary concern.

Choosing the right pump for your application can sometimes be an easy choice to make but sometimes we need some guidance and support which is where we can help.  There are many ways to connect, but if you call 01933 674777 an experienced engineer will be hand to offer support and advice for your next project.