A central vacuum system (CVS) is designed to serve a number of users who are connecting and disconnecting from the CVS unpredictably. When they do, this creates sudden pressure changes. An example is that, when a filtration is completed, air can flow freely through the filter and into the vacuum system because the liquid no longer serves to “plug” the vacuum port. In essence, it creates a leak into the vacuum system that persists until the port is closed. Since a vacuum system with a leak is not very effective at providing vacuum, this condition reduces the vacuum available on the CVS for other users, interfering with their work. The same effect occurs when boiling begins in an evaporative application. The sudden flow of vapor reduces the vacuum level within the system. For other users of the network, the changes from desired conditions can cause “bumping” and possible sample loss, or less than optimal vacuum conditions. It is even possible for cross-contamination to occur. Cross-contamination happens when gas or chemical vapor drawn into the vacuum system at one port actually flows out of the vacuum system at an adjacent port that has been operating at a lower pressure (greater vacuum) than that available in the lines after another port is open, or evaporation begins at another location. Clearly, this poses a risk to the integrity of the work of scientists using a CVS. The video below demonstrates the potential risk of cross-contamination in a traditional lab vacuum system.
VACUU·LAN networks are likewise designed to accommodate a number of simultaneous users who are connecting and disconnecting from the network unpredictably. However, VACUU·LAN networks are designed to minimize the pressure variations within the network when users open and close vacuum ports. Besides providing stable vacuum to scientists, this also minimizes the potential for interference between users and cross-contamination.