Design and manufacture of long fiber thermoplastic composite frost plate for water meter protection

Long fiber thermoplastics (LFT) composites have been increasingly used in various applications because they possess great mechanical properties and excellent processability. Other advantages of using LFT composites include low cost and exceptional corrosion resistance, enabling them to be candidates for corrosion-prone applications. This work focuses on the design, validation, and prototyping of a water meter frost plate using long glass fiber reinforced thermoplastic composites. Before prototyping, the LFT composite frost plates were modeled with finite element analysis for iteration and evaluation. The deflection and stresses responses under normal and freezing operation conditions were simulated to validate the functionalities of a slip-on feature, resistance to nominal water pressure, and self-sacrifice capability. After validation of the functionality of self-sacrifice and protection of the water meter, frost plates were prototyped with an extrusion compression molding process using LFT glass fiber reinforced polyphenylene sulfide (glass/PPS) and LFT glass fiber reinforced nylon 66 (glass/nylon 66). The molded LFT composite frost plate was tested in normal and frozen operation conditions to evaluate its performance. It was found that the designed frost plate was able to prevent water leakage from normal water pressure and protect the water meter as designed by fracturing at the bolt area when the water freezes. The fracture location matched well with the maximum stresses observed from the modeling result. It is concluded that LFT composites can be an alternative material to replace the metallic counterpart to provide protection for the water meter during freezing conditions.