What is the difference between a sealed and a Nonsealed system

With sealed systems, the capacity of the pump is determined by the time required to evacuate the system to a set vacuum level. This is called the evacuation time of the pump and is normally specified in milliseconds per litre (ms/l).

With non-sealed systems (lifting of porous materials) the case is different. To maintain the desired vacuum level the pump must have the capacity to pump away the air leaking in. By establishing the leaking flow, it is possible, by reading the pump data, to find the right pump for the application in question.

 

When the leakage occurs through a porous material or in an unknown way, the flow can be established by a test with a vacuum pump. The pump is connected to the system and the obtained vacuum level is read. (It should be at least -40 kPa (-12inHg)). The flow that is pumped away at this vacuum level can be seen on the page of the particular pump (in the Vacuum Automation catalog). This flow roughly corresponds to the leaking flow.