Plastic Insert

Plastic Insert

Tube insert is inserted into the end of a heat exchanger tube to provide protection to the Tube mouth ends of a shell & tube type heat exchanger. The purpose of the tube insert is to either be sacrificial to the effects of inlet-end erosion, corrosion, impingement, or induce a fluid to fall on the ID of a tube in a falling film exchanger, or transfer extremely high heat past the tube sheet to the exchanger tubes.

The following problems take place in the Shell & Tube Type Heat Exchangers

  • Tube-end erosion/corrosion
  • Stress Corrosion Cracking
  • Crevice corrosion
  • Localized pitting
  • Ammonia grooving
  • Improper tube expansion
  • Weakened tube-to-tube sheet joints

For the above problems, VP Engineers (VP ENGINEERS) offers its most cost-effective tube repair, Shield/Seal, also known as a tube insert or ferrule. Although inserts are typically only 6" - 12" long, some applications have required Shield lengths up to 14 feet! Unfortunately, some exchangers suffer from full-length problems. In this case, VP ENGINEERS Full Length Tube Liners can be a very attractive alternative to a partial or full re-tubing.

Material of Construction (MOC):

Plastics : Nylon ( Polyamide ), LDPE, PP.

Plastic Inserts comes with two types of head design


Bonnet Head which is used when the tube slightly projects for about 3 to 5 mm outside the Tube sheet. The Bonnet Head encapsulates the projection in such a way that the high velocity impingement does not affect the Tube mouth end & thus ensures the longevity of tube mouth end & Tube.

Flared head

Flared Head which is used when the Tube does not project outside the Tube sheet. Plastic Inserts are generally preferred in Surface Condensers of a Power Plant. Nylon Tube Inserts can be used up to 150 Deg. C, for some special applications even PTFE Tube Inserts are used for temperatures up to 250 Deg C. Plastic Tube Inserts in different type of Heat Exchangers of different duties for Temperatures up to 800 Deg C.

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