Tag: corrosion resistant

EXAIR Offers An Easy Way to Improve Your Metal Dipping Process

Published on by John BallLeave a comment

A company had a process where they galvanized metal sheets to protect them from corrosion.  The system consisted of six baths to properly coat the metal.  In order, it was a caustic wash, water rinse, pickling, water rinse, flux solution, and then zinc galvanizing.  The sheets were 126” (3.2 meters) wide, and the sequence consisted of the parts being dipped into each bath for a certain length of time.  The parts would then be raised above the solution to drip prior to moving to the next bath.  This customer was looking for a better way to improve the process as well as to help reduce the drips and runs from the hot galvanizing, which were manually “rubbed” out before hardening.  They contacted EXAIR to find a solution. 

With similar applications, EXAIR has a great product for non-contact wiping flat surfaces. We call them Super Air Knives.  I wrote a blog similar to this on a much smaller scale; “How a Super Air Knife Helps with Metal Etching“. The Super Air Knives use compressed air to generate a force at varying degrees.  With the engineered design, we are able to add free ambient air at a rate of 40:1.  For every one part of compressed air, the Super Air Knives can entrain 40 parts of ambient air.  With the Super Air Knives, we can generate a laminar flow to give an even force across the entire length.  So, it is easy to set the correct force for different types of liquids and viscosities. 

With the caustic solution and corrosive environment, I recommended our Super Air Knife in 316 Stainless Steel material for superior anti-corrosion qualities.  EXAIR stocks 316 stainless steel Super Air Knives in many lengths.  For this application, the width to cover this metal sheet was a bit outside our longest single air knife, which is 108” (2.7 meters).  But, EXAIR does offer a Coupling Kit as a way of making our Super Air Knives even longer as multi-unit assemblies.  We can couple the Super Air Knives together to reach across, and still keep the flow even.  For this application, I recommended model 110054SS-316, 54” (1,372 mm) and model 110072SS-316 (1,829 mm) to be joined together with our coupling kit, model 10900SS-316, to accommodate the 126” (3.2 meters) width required for the application.   

The customer decided to place one set of coupled Super Air Knives on each side of the material for the caustic bath, pickling bath, flux bath, and hot dip galvanizing bath.  They mounted them above each tank, blowing at a compound angle, in and down toward the dip tank.  The Super Air Knives would be turned on automatically only when the metal sheet was being removed from the solution.  The excess liquid is forced back into the same dipping tank the material is drawn from.  With a regulator, our customer is able to control the amount of force to get the best results without overusing the compressed air.  Another benefit they enjoyed was that as more solution is removed from the material between each bath, the less liquid that is transferred from one solution bath to the next; thus, reducing cross-contamination dramatically.

After installing Super Air Knives in their system, they started to see a vast improvement in their process.  The excess drips were removed without surface issues, and they were able to extend the life of their rinse tanks by 40%.  As an added bonus, the Super Air Knives decreased the time at each bath, improving productivity without the additional labor cost.  Less waste and faster production times are the solutions that the EXAIR Super Air Knives provide the customer.  If you have a similar application and want to discuss how we can improve your dipping process, please speak to our Application Engineers.  We’d be happy to help.

John Ball
Application Engineer
Email: johnball@exair.com
Twitter: @EXAIR_jb

Photo: textured galvanized iron by makamuki0.  Pixabay Content License

316 Stainless Steel Products- Always in Stock

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Metallurgically speaking, stainless steel is a steel alloy with the highest percentage contents of iron, chromium and nickel, with a minimum of 10.5% chromium content by mass, and a maximum of 1.2% of carbon by mass.

Stainless steels are widely regarded for the corrosion resistance that they exhibit. As the chromium content is raised, the corrosion resistance increases as well. The addition of molybdenum also increases the corrosion resistance to reducing acids and against pitting attacks in chloride solutions. By varying the chromium and molybdenum content, different grades of stainless steel are produced with each suited for varying environments. Due to the resistance to corrosion and staining, stainless steel is ideal material for many applications, especially in the food, pharmaceutical, and chemical industries.

The 300 series stainless steels are considered chromium-nickel alloys and is the largest group and most commonly used. Of the different compositions within the 300 series family, Type 304 stainless is the most widely used followed by Type 316, which has 2% molybdenum added to provide greater resistance to acids and to localized corrosion caused by chloride ions.

Table below shows the nominal composition by mass content for 316 stainless steel

316 SS Table

Because 316 stainless steel provides a high level of corrosion resistance, resists pitting, and has good strength properties, EXAIR manufactures many of its products from 316 stainless steel material so that they can be used in the harshest of environments.

Of the EXAIR products these are available off the shelf in 316 stainless steel- Super Air Knife, certain sizes of Adjustable Air Amplifiers, numerous Air Nozzles, Line Vacs including the Sanitary Flanged style, NEMA Type 4X and Hazardous Location Cabinet Coolers. If you need one of our other products such as the Super Air Wipes or Vortex Tubes made in 316 stainless steel, just let us know. Of course we also have them made from Type 303 stainless steel, in stock and ready for shipment (and aluminum, too!)

gh_stainless-steel-super-air-knife-750x696.jpg
316 Stainless Steel Super Air Knife

And, you don’t have to wait months or even weeks, as we keep all of these in stock, ready for shipment.

If you have questions about any of the 15 different EXAIR Intelligent Compressed Air® Product lines, feel free to contact EXAIR and myself or any of our Application Engineers can help you determine the best solution.

Brian Bergmann
Application Engineer
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Twitter: @EXAIR_BB

Many Air Knife Materials and Shim Options to Suit Your Application

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The EXAIR Super Air Knives are used in many applications ranging from part drying, to web cleaning, to conveyor blowoff, and many other uses. For most processes, the aluminum models provide the performance required and withstand the environmental conditions present.

Ambient temperature limits for the aluminum models is 180°F (82°C). EXAIR also offers the air knives in types 303 and 316 Stainless Steel, which increase the temperature limit to 800°F (427°C) and provides a great degree of corrosion resistance. For the harshest, most corrosive environments, an air knife constructed of Polyvinylidene Fluoride (PVDF) with a temperature limit to 275°F (135°C) is available.

Super Air Knives
Aluminum, Stainless Steel and PVDF Super Air Knives

But what can we do about those applications where the increased corrosion resistance isn’t needed and the temperatures do not approach anywhere near to 800°F (427°C)?

The solution to this situation is an aluminum air knife with a custom stainless steel shim. The aluminum material is rated to 400°F (204°C) and the shim is good to 800°F (427°C) so this knife can be used in those hotter environments up to 400°F (204°C). This option helps to keep the cost of the knife low, by utilizing the lower cost aluminum for the body and cap.

The table below details the materials of construction options for the Super Air Knife – a wide array of material offerings to suit even the hottest, harshest conditions.

Air Knife Temperature Table

We recommend consulting with an Application Engineer to review the application, process, and environmental conditions, and we can present best options.

And don’t forget, the shims can be further customized for special blowoff requirements. See the blog that my colleague, Russ Bowman, posted here.

If you have questions about Super Air Knives or any of the 15 different EXAIR Intelligent Compressed Air® Product lines, feel free to contact EXAIR and myself or any of our Application Engineers can help you determine the best solution.

Brian Bergmann
Application Engineer
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Twitter: @EXAIR_BB

Where Can’t I Use An EXAIR Super Air Knife?

Published on by Russ BowmanLeave a comment

Considering the material options available, there are very few places you CAN’T use a Super Air Knife. Most often, we find those to be due to extreme elevated temperature, like this one:

A caller from a glass manufacturing company wanted to replace a drilled pipe in a cooling application. Thing is, glass makers deal with their product in molten form, which is HOT…the ambient temperature that this drilled pipe is exposed to reaches 800°C, or 1,472°F.  Because of the temperature, and corrosive atmospheric elements (SO2 is also present, as if the heat wasn’t bad enough,) they have to replace the drilled pipe every so often, and wanted to explore other solutions.

Now, this was a rare case where a Super Air Knife would not have necessarily offered an improvement over a drilled pipe:

  • The air flow from the drilled pipe is primarily straight from their compressed air system.  Since the Super Air Knife entrains air from the surrounding environment at a rate of 40:1, the resultant flow would be very close to the 800°C ambient temperature…and not as effective at cooling as the much cooler compressed air supply temperature.  It wouldn’t have helped to reduce consumption if it simply didn’t work.

The Super Air Knife takes a supply of compressed air (1), discharges it through a gap that runs the length of the Air Knife (2,) and entrains an enormous amount of “free” air from the surrounding environment (3.)

  • Another great thing about the Super Air Knife is that it’s dramatically quieter than any other method of compressed air blowing.  Of course, if you find yourself in a 800°C sulfur dioxide environment, hearing protection is the least of your concerns.

    When supplied at 80psig, the EXAIR Super Air Knife produces a hard hitting, powerful curtain of air, with a sound level of only 69dBA.
  • EXAIR Super Air Knives (and all of our Intelligent Compressed Air Products) are compliant with OSHA Standard 1910.242(b) which limits the outlet pressure of a compressed air blowing device used for cleaning to 30psi…this protects personnel from high velocity debris and air embolisms.  Again, not a concern in an unoccupied (and uninhabitable) space.

Again, that’s a rare case…a very specific exception to a broadly inclusive rule, in light of the options EXAIR offers.  Consider:

  • Aluminum Super Air Knives are durable, lightweight, and suitable for most any installation in a typical industrial/commercial environment.  They’re good to 180°F (82°C) and are fitted with stainless steel fasteners to eliminate corrosion in damp environments.  The polyester shim can be replaced with a custom stainless steel shim, increasing the temperature rating to 400°F (204°C) if needed.
  • Type 303 Stainless Steel Super Air Knives offer higher tensile strength, and are good to 800°F (427°C.)  They are popular in applications with factors like high heat, corrosive environments, frequent spray down cleaning, outdoor installations, etc.
  • Type 316 Stainless Steel Super Air Knives are often specified in food and pharmaceutical applications, due to their even higher resistance to chemical attack and pitting.  They’re also rated to 800°F (427°C) and have the same high tensile strength as the Type 303 Stainless Steel models.
  • Some situations call for better corrosion resistance than these high grades of austenitic stainless steels – and that’s where EXAIR’s PVDF Super Air Knife comes in.  Fitted with PTFE shims and Hastelloy© C-276 hardware, they are especially well suited for processes involving the harshest of corrosive agents, such as electroplating, solar cell manufacturing, and lithium ion battery production, just to mention a few.  They would, in fact, be ideal for the SO2 environment at the glass factory, if it weren’t for the temperature…they’re rated to 275°F (135°C.)

Performance is identical, regardless of construction materials, and all EXAIR Super Air Knives come in lengths from 3″ to 108″ (except PVDF…those go up to 54″ lengths) and ship quickly from our well maintained inventory.  Aluminum and Stainless Steel models can be coupled together for even longer flow lengths.  Plumbing Kits and Universal Air Knife Mounting Systems make for easy and quick installation, and all Super Air Knife Kits come with an Automatic Drain Filter Separator, a Pressure Regulator, and a Shim Set for reliability, clean air flow, and total performance control.

If you need a reliable, cost effective, safe, quiet, and efficient curtain of air, EXAIR’s Super Air Knives are what you’re looking for.  If you’d like to discuss a particular application and/or product selection, give me a call.

Russ Bowman
Application Engineer
EXAIR Corporation
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