Super Air Knives Are Ideal For Super Aggressive Environments

Hydrochloric Acid. Sodium Hydroxide. Nitric Acid. Hydrogen Peroxide. Whether you know it or not, these are all commonly used around the house as tile/grout cleaners, drain openers, lawn fertilizers, and disinfectant for cut & scrapes, respectively.

They’re also used in a variety of industrial applications, such as the making of plastics, glass, pharmaceuticals, and wastewater treatment, respectively…all of which also have applications for which EXAIR Corporation’s Intelligent Compressed Air Products provide safe, efficient, and quiet solutions for.

Stainless Steel Super Air Knife Kits include the Air Knife itself, a Shim Set, an Automatic Drain Filter Separator, and a Pressure Regulator. The Air Knife & Shim Set are all Stainless Steel (grade 303 or 316, depending on which is specified) construction.

Consider the Super Air Knife: If you need one that’ll stand up to contact with hydrochloric acid, you’re looking for PVDF construction. Nitric acid is a different story – our 303SS, 316SS construction Super Air Knives are well suited for those applications.

On the other end of the (pH) spectrum, any of those materials are suitable for exposure to Sodium Hydroxide. PVDF is still the best choice, as the Stainless Steels will be subject to discoloration or slight corrosion, depending on the concentration.

PVDF Super Air Knife Kits include the Air Knife itself (PVDF body, Hastelloy C-276 hardware, and PTFE Shims,) a PTFE Shim Set, an Automatic Drain Filter Separator, and Pressure Regulator.

Acids and bases aside, oxidizers are also very corrosive, especially in higher concentrations.  Hydrogen peroxide is a commonly used oxidizer in industries as diverse as pulp & paper, soap & detergent, and water sterilization.  Like other chemicals, compatibility depends on the concentration, but like nitric acid & sodium hydroxide, our PVDF Super Air Knives are still the best, but the Stainless Steel models are still acceptable.

These are just a few, very basic, examples of chemical compatibility.  If you have an application that calls for installing one of our compressed air products in an area where you’re concerned about corrosion, give me a call.

Russ Bowman
Application Engineer
EXAIR Corporation
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Submarines, Shipwrecks, Air Knives, and Corrosion

Monday was a notable day in naval warfare history. On February 17th, 1864, the H.L. Hunley sank the USS Housatonic, a Union sloop that was blockading the harbor in Charleston, South Carolina, during the American Civil War. In doing so, the Hunley became the first combat submarine to sink a warship in battle. Unfortunately, they never returned.

Treasure hunters and archaeologists searched for the sunken vessel in the years following the war. Despite grand efforts, one even spurred by a $100,000 reward offer from legendary showman P.T. Barnum, the ship and crew were lost to history until 1995. So many people had mistakenly thought they’d found the wreckage that when underwater archaeologist Harry Pecorelli actually did find it, he radioed to his boat, “I don’t know what it is, but it is definitely not the Hunley.” Because of this, the preservation group, Friends Of The Hunley, have affectionately dubbed him “the first person to have never found the Hunley.”

In 2000, the intact ship was raised and placed in a specially built tank, where the conservation team immediately went to work. Because of her iron construction and age, this turned out to be an engineering (mechanical and chemical) feat like no other. Over the next four years, precision excavation efforts allowed the team to exhume the remains of the crew, and they were buried with full military honors in the spring of 2004. They still haven’t proven conclusively why the Hunley sank, but as restoration work continues, she may give up her final secrets yet, as long as they can keep corrosion at bay.

hunley in tank

The prevalent use of aggressive chemicals in certain manufacturing processes today can likewise take their toll on equipment made from materials that aren’t compatible for use in these environments. As advances have been made in the development of these chemicals, metallurgists and materials engineers have kept pace in the field of corrosion resistance. EXAIR has taken full advantage of these innovations by offering our Super Air Knives in a variety of materials that can stand up to just about whatever you can throw at them:

Two grades of Stainless Steel are available: Type 303 is well suited to mildly corrosive environments. Type 316 offers even better corrosion resistance, and is often specified in the food, pharmaceutical, and surgical product industries. Both are also good to 800°F (427°C).

PVDF (Polyvinylidene Fluoride) Super Air Knives are resistant to harsh conditions where UV light, inorganic chemicals, solvents, ozone, weather, fungi, chlorinated hydrocarbons, strong acids, and/or salts are present. They are equipped with PTFE shims, 316SS pipe plugs, and Hastelloy C-276 hardware for superior performance in the most aggressive environments.  These are rated for temperatures up to 275°F (135°C).

Of course, if your application doesn’t concern any of these, our Super Air Knives in aircraft grade aluminum construction are perfect for general purpose applications in standard conditions. Just about wherever you need to install it, though, EXAIR has a Super Air Knife that is up to the task. Try us.

Russ Bowman
RussBowman@EXAIR.com
@EXAIR_RB