Harp Screen Installation & Removal 101 – Tips from Samscreen

Samscreen, Inc. has long been recognized as the leading manufacturer of piano wire screens, also known as harp screens, for the portable screening market. We manufacture harp screens for all makes and models of portable screening plants, and can custom manufacture screens for special applications and machines. Our experienced customer service staff can help you make sure you get the proper screen and the proper fit.

Samscreen suggests some instructions regarding the installation and removal of harp screens. The following are the some of the most important steps to kept in mind:

Harp Screen Installation

  • Remove the Samscreen from the box. Be careful with heavy wire screens as they are packed under tension and may spring out when unrolling them.
  • Place the first hook at the anchor end of the screen box. Make sure that it seats itself correctly.
  • Pull the screen towards the tension end of the screen box. Spread the moving profile strips to match up with the cross members of the screen box.
  • Place the free hook in the tension envelope and insert the spring/tension bar. Make sure that the tension bar is all the way to the back of the hook and seated properly.
  • Take up the slack in the screen by tightening the tension nuts. When the wires in the screen have initially straightened make sure the anchor end hook is still seated, that the profile strips are located right above the cross members and that the tension bar is seated correctly in the back of the tension hook.
  • Start to tension the screen. Use two turn increments and rotate the order of tightening. Continue to tighten in this manner until the screen is taut. It is normal for center wires to tighten first and then the outside wires. If you experience the opposite loosen the screen and check that the spring bar has been inserted the correct way.
  • Proper tension is achieved when all the wires on the screen are tight. It should be possible to run your fingers over the screen and pluck individual wires and hear them sing.
  • Make sure that the profile strip has seated itself correctly over the cross members and that it is straight across the deck. Run the machine for one or two hours, the stop it and check tension on the screen again. Tighten again if necessary.

Harp Screen Removal

  • Turn screening plant off and wait for the screen box to stop vibrating and all moving parts to stop moving.
  • Go to the tension end of the screen box and loosen the tension nuts on the side of the screen box. If there are four nuts loosen them in half turn increments and in rotation until the tension is off the screen you are removing. If there are two nuts, loosen them in half turn increments also. Once the tension is released, it is OK to remove the nuts completely. If the tension “UBOLT” can fall away from the machine leave the nuts turned one or two threads.
  • Remove the piano wire screen from the tension envelope. This may be achieved by hitting the spring or tension bar with a rubber mallet. If you have removed the tension nuts completely, stay clear of the hook and spring bar as they exit from the tension envelope.
  • Remove the spring bar from the hook. If the clearance is available simply leave the spring bar in position and push the screen towards the anchor end. If the clearance is not available, slide the spring bar through the tension take up slot in the screen box sides.
  • Pull the hook from the anchor end and discard the screen in a suitable container. Check the tension and anchor ends of the screen box for material build up that may interfere with the installation of the new screen. Also check the cross members for any wear, looseness or bends. If any of these conditions exist, they must be repaired prior to installation of the new screen because un-repaired they will have a negative effect on the service life of the screen.

Of course, our friendly customer service staff is always available to answer any questions you might have. Please feel free to call us at (888) 344-3653 for assistance.