ANSI HI 9.3-2000 pdf download Pumps – Polymer Material Selection
9.3.3 Polymers Materials
9.3.3.1 Introduction Table 9. 5 is a guide for the selection of polymers, both thermoplastic and thermoset, suitable for exposure to various liquids. The continuous temperature rating shown should result in no attack on the polymer by the liquids. For temperatures exceeding these ratings, even for a short period, consult the manufacturer. The tensile strength and modulus of elasticity of polymers decrease significantly with increasing temperature and are the primary limitations for application. The other application criteria is the resistance to corrosion by the liquid. This resistance depends on the concentration of corrosive chemicals and the temperature of the liquid.
Two types of polymer materialsthermoplastics (TP) and thermosets (TS) are used in polymer pumps. Thermoplastics are usually thin wall members with lower allowable temperatures, and pressures. They are smaller weight pieces and melt when excessive heat is applied to them. Thermosets can be heavy wall, high pressure, large components and char when excessive heat is applied. Typical characteristics of pump construction of two polymer types are as follows, These characteristics are for a preliminary guide only. Depending on design, these values may be higher.
Both thermoplastics and thermosets are usually internally reinforced by the addition of glass or carbon fibers. The addition of the reinforcement can double the tensile strength in many of the polymers. When selecting materials for a liquid, the limiting criteria may be the attack of the liquid on the reinforcementnot the polymer.
Table 9.5 assumes the addition of glass or carbon fiber reinforcement. Since this guide is for a pump (pressure boundary parts), the limiting temperature is shown only for continuous applications. This guide does not apply to lined pumps. If a polymer is not recommended, it is identified as NR. When no data was available a dash (-) is indicated. Polymers are also used for non-pressure parts such as wear rings and bushings, and may have higher temperature ratings than shown.
9.3.3.2 Polymers Used Table 9.5 identifies eleven different polymers which are used in pump construction. These are as follows: