A manufacturer of synthetic roof shakes contacted me about a cooling application.  Their style of roof shake is made of a synthetic compound that is molded to look like cedar or stone in a variety of different colors.  They contacted EXAIR because they were getting a “bump” on the face of the roof shake.  It was determined that the vacuum cups used to move them were causing the defect.  The molded product did not have enough time to cool before the 2” (51mm) vacuum cups created an impression on the face.  In order to keep the quality department from rejecting the parts, they would have to wait for them to cool sufficiently before they could move them, costing them money.

The part was coming out of the machine at 300 deg. F (149 deg. C).  With the cycle time of the operation, they needed to try and cool the part just enough to harden the material before the vacuum was applied.  This would insure that the synthetic material would not deform.  The molding process created two shakes at a time.  A robot arm with the vacuum system would grab each shake using two suction cups.

Converting the size of the area to cool, I was able to calculate the estimated time to reduce the temperature to 200 deg. F (93 deg. C).  (This was from a previous blog, “Let’s Cool Things Down with Heat Transfer Equations”).  I recommended the 3225 Vortex Tubes.  It would only take 1 second to cool to the desired temperature.  And that was plenty enough time for this operation to resist the vacuum pressure.   I also recommended the model 3902 generator kit.  It would give the customer the ability to change the cooling capacity from 650 to 2,800 BTU/hr (164 to 706 Kcal/hr) for different weights and styles of roof shakes.  The Vortex Tube generators are easy to change for quick changes in cooling capacity.  I also suggested the 5901 single point hose kit to aim the cool air to the exact location.

EXAIR stocks our catalog products; so, the customer was able to be in full production status without defects within 24 hours of talking to an Application Engineer.

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