HIGH PRESSURE HOMOGENIZER

A high pressure homogenizer for flowable substances charged with particles, having a high pressure chamber and a homogenizer unit that is located fluidically downstream thereof and, by swirling, expands the fluid to be homogenized which has previously been brought to a pressure of more than 500 bar in the high pressure chamber, and a plunger pump associated with the homogenizer unit, the plunger of which plunger pump pressurizes the high pressure chamber, wherein the high pressure homogenizer has a low pressure chamber which surrounds the plunger shaft to cool the plunger and which has an operating pressure of PN≤25 bar, wherein the low pressure chamber and the high pressure chamber are separated from each other by a seal which is penetrated by the plunger, the seal being a throttle gap which is formed between the plunger shaft and a bushing that does not contact the plunger shaft, the ratio S/L of the length to the radial annular gap height of the throttle gap being ≤0.0015.