Replacing the Double Delta Seals

To replace the double delta seals on the pistons, do the following:

  1. Remove the backing plate. Refer to Removing and Installing the Backing Plate for more information.
  2. If equipped, remove the center plate. Refer to the ultra valve gate hot runner manual (If Equipped) for more information.
  3. Remove the valve stem assemblies. Refer to Removing and Installing Valve Stems for more information.
  4. For each valve stem assembly that requires new double delta seals, do the following:
    1. For VG-LX/EX hot runners only, remove, clean and inspect the piston cylinder. If the piston cylinder is damaged, replace it immediately.
      Figure 1. Piston Cylinder Inspection

      1. Good Piston Cylinder

      2. Damaged Piston Cylinder

      CAUTION:

      Mechanical hazard – risk of damage to the equipment. Do not damage the pistons when removing the seals. This will later diminish the integrity of the new seals.

    2. Remove the outer and inner seals from the piston.
      Important:

      Pistons must be cleaned before new seals are installed. Any debris or grease present will shorten the service life of the seals.

    3. Remove any loose debris or grease from the piston and surrounding area.
    4. Install the interior O-ring seal into the seal groove by rolling it over the piston. No tools are required.
      Figure 2. Installing the Inner O-Ring Seal

      1. Piston

      2. Inner O-Ring Seal

    5. Place the seal installation tool on top of the piston.
      Figure 3. Installing the Outer O-Ring Seal

      1. Seal Installation Tool

      2. Outer O-Ring Seal

      3. Piston

    6. Install the outer O-ring seal by pushing the seal over the seal installation tool until it sits over the interior O-ring seal.
    7. Remove the seal installation tool.
    8. Slide the piston installation tool over the piston to compress the seals. This will protect the seals from damage when the piston cylinder is installed.
    9. Inspect the piston assembly for damage, debris or grease.
      Note:

      The piston cylinder is easier to install when it is installed shortly after the piston installation tool is removed.

    10. For VG-LX/EX hot runners only, install the piston cylinder.
  5. Install the valve stem assemblies. Refer to Removing and Installing Valve Stems for more information.
  6. If equipped, install the center plate. Refer to the Ultra Valve Gate Hot Runner Manual for more information.
  7. Install the backing plate. Refer to Removing and Installing the Backing Plate for more information.
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