Why would valves and pump seals continually failing?
Repeated failure of valve seats or O-rings and internally flushed mechanical pump seals is normally because of an incompatibility with propylene glycol and the valve and seal components. It is less likely that the fluid has been contaminated by a solvent. See below for comments about materials compatibility and more specifically about pump seals. • In general, Buna N represents one of the least compatible elastomers with propylene glycol based fluids such as DOWFROST™ HD inhibited propylene glycol. See the attached article which talks in general terms about compatibility and suggests a maximum temperature of 90 F for Buna N. Note that typical recipes for elastomers contain, besides the polymer, curatives, reinforcing fillers (e.g. carbon blacks, diatomaceous earth), sometimes metal oxides and other processing aids as necessary. The use of these different compounding materials in formulating elastomeric components can have a significant effect on the performance of the elastomer in serv
