Manufacturing Process



HLB manufactures its GRP pipes with its original Self developed filament winding equipment. Wind the mandrel surface until it reaches a guaranteed thickness with resin-saturated glass fiber. The equipment winds around the mandrel from end to end with fiber glass at the physically optimal winding angle so each fiberglass thread crosses over each other. Once the pipe is fully wound, it is dried and removed from the mandrel and further processed to fit the application.
This process is essential to achieving unity and high quality in GRE/GRP pipes.

Hand Lay-up

The hand lay-up technique is a common way to produce GRE / GRP pipes. First, a release gel is sprayed on the mold surface, which is further covered with a surface mat with a thickness of 0.3~0.5mm. Then, roving cloth is applied to the extent that the intended thickness/strength is achieved. Hand lay-up features a broad application for complicated designs and for small and large pipes, and is mainly used to fabricate fittings such as elbows and reducers.

Joint Method

  • Bell and spigot

    Bell and spigot Adhesives are sprayed to the processed end and inserted.
    Bell and Spigot is time-efficient and precise, and can withstand high pressures.

  • Butt and wrap

    Butt and wrap The end of each side to be grinded and lamination will be implemented on this butt joint.
    Butt and Wrap is highly processable, easily modified, and optimal for adjustment work.

  • Flange joint

    Flange joint Flanges are manufactured in ANSI, JIS and DIN standards like other steel pipe flanges, and are compatible to be flanged with pipes of other materials.

  • Double O-Ring Expansion coupling joint

    Double O-Ring Expansion coupling joint Double O-ring Expansion coupling joints are usually used to reduce external stress, and are connected with Double O-rings and Lock-keys.
    Mainly used in ballast systems subjected to sagging / hogging.