Tough and heavy fluids are a significant challenge for pump dispensers. Due to the resistance of a viscous fluid, gaps are easily created in the fluid during pumping - the pumping action suddenly stops.

Joma therefore favours the vacuum pump system. The overflow sleeve, which rests on the fluid, prevents unwanted air pockets and transports liquids and even highly viscous fluids evenly through the standpipe. It seals cleanly against the container wall and hygienically prevents the contents from drying out.