A limitation of inspectable plate exchangers is related to the duration of gaskets, and the maximum temperatures they can bear, that varies depending on the kind of elastomer employed along with their specific chemical resistance. Some example:
These values must be coupled with the effective working pressures: at higher temperatures, rubber softens indeed and therefore is able to sustain reduced working pressures. There are gaskets able to bear working pressures up to 21 bar, but their flexibility changes and declines anyway with the aging of the gasket. Duration and sealing capacity of the elastomer can as well be compromised by factors such as temperature and characteristics of the fluids, process conditions, suspended particles and an improper employ of cleaning fluids. These factors could cause the wear and breaking of gaskets, compromising the functioning of the exchanger.
A proper suitable maintenance schedule is then highly recommended in order to periodically check the status of gaskets, providing their substitution in case of deterioration. Possibly along with a cleaning of plates and thermal transfer surfaces and an overall check of the conditions of the exchanger. Aimed to this it could also be very useful to equip the exchanger with proper condition monitoring systems.
Thinking about maintenance and working life cycle of plate heat exchangers, clip gaskets are finally a truly valid alternative compared to glued gaskets, because they can be removed in case of opening and cleaning of the exchanger, and then mounted back in place rapidly and without the need of glues.