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FAQs: Air Knife

Below is a list of Frequently Asked Questions relating to our Air Knife. If you need additional help with your application and/or can't find an answer to your question, please call our factory at 1-705-770-4455 or email an Application Engineer at support@stream-tek.com.

      1. Will the Air Knife operate with a blower?
      No. The Air Knife is designed to use only compressed air. Blowers are very noisy, large, and expensive with 3" to 6" connections. They simply will not produce enough force to operate our Air Knife.
      2. Can I cut the Air Knife to a custom length?
      No. The Air Knife is precision machined, cutting it would expose the internal design with no way to reseal the air knife. With that said, custom sizes can be machined upon special request.
      3. Can I connect the cold end of a Vortex Tubes to an Air Knife?
      No. This would cause an airflow restriction which would instantly produce back-pressure in excess of 5 PSIG! When this back-pressure is exceeded, performance of the Vortex Tube will be negatively impacted. The hot end of the Vortex Tube on the other hand can withstand a pressure up to 30 PSIG (depending on the cold fraction).
      4. What is the recommended pressure that should be used with the Air Knife?
      Always try to use the lowest pressure that is possible for your application. Always use a pressure regulator to increase force/airflow to the point where your application problem is rectified. The maximum pressure of the Air Knife is 250 PSIG.
      5. How do I mount the Air Knife?
      Rigid compressed air pipe is the best way to mount the advanced air knife (air curtain). If this is not possible, there are multiple 1/4-20 mounting holes located on the back of the Air Knife.
      6. Can you make Advanced Air Knives over 54" or other lengths you do not stock?
      Yes. We have the capabilities to manufacture up to 109" long Air Knives. In addition, any length air knife can be machined upon special request. Lead time for custom orders is typically 2-3 weeks.
      7. What temperatures can your Air Knives withstand?
      Aluminum Air Knife:
      275°F (135°C)

      Stainless Steel (Type 303) Air Knife:
      400°F (204°C)

      Stainless Steel (Type 316) Air Knife:
      800°F (427°C)

      * Temperatures that exceed 800ºF (427ºC) could produce intergranular corrosion which could eventually plug the air gap opening
      8. There isn't enough airflow coming out of my air knife! Do i need more shims?
      Before you increase the standard gap opening of .002", it's important to ensure your Air Knife is working properly. The low flow can be caused by a clogged filter, undersize lines, undersized air compressor, restrictive fittings or even particles clogging up the gap between the air knife body and cap.

      To verify that full line pressure is available, install a pipe-tee along with a pressure gauge at any one of the inlets of the air knife. If full line pressure is present and additional flow is needed, turn off the compressed air supply and disassemble your air knife. Be sure to clean the air knife body, cap & shim before reassembling with the additional shim. Tighten each screw to 7.5 ft/lbs.
      9. My Air knife has dead spots. What can i do?
      Each and every air knife that leaves our facility is tested to ensure proper flow characteristics. We suggest that you examine the below (3) three possibilities that may cause these dead spots.

      i) Inspect air knife for direct contamination and/or clogging. Cleaning instructions are found in the Installation & Maintenance sheet supplied with your air knife.
      ii) Screws may have been over tightened during reassembly or mounting. Screws should be tightened to 7.5 ft/lbs.
      iii) Air knife may be undersupplied. Do not use undersized lines, filters or restrictive fittings that may not allow enough airflow into the plenum chamber of the air knife.
      10. How can i get more force out of my air knife?
      A higher force of air flow can be achieved by increasing the volume of air that's being throttled through the air knife. There are (2) two ways to do this:

      i) Increase the supply pressure. Maximum safe level is 250 PSIG!
      ii) Install additional shim(s).

      ** Both of the above will have a direct effect on the volume of compressed air that is required to supply your air knife. Therefore proper plumbing modifications should be taken into consideration.
      11. Which way does the airflow form your air knife need to be pointed?
      The STREAMTEK Air Knife is not position sensitive. It is effective when pointed in any direction.