Negative pressure blanketing

Below is an example diagram of SUPPRESSURE SUPPRESSION with INERTGAS. Negative pressure blanketing is used to maintain a slight negative pressure compared to the atmosphere in storage tanks, stirred tanks or other volumes. This effectively prevents the escape of toxic or hazardous product.

The two necessary vacuum regulators are usually set and sealed, for example: Vacuum regulator -40 mbar Vacuum limiter -10 mbar. The minimum difference between the two set values should be at least 15 mbar. If nitrogen, and therefore product loss, is to be minimized, the two setting values should be set further apart. This prevents nitrogen from being added even by small temperature fluctuations.

The outlet volume from the tank determines the capacity of the vacuum regulator; the capacity of the vacuum limiter must be matched to the inlet volume.

The fan draws the tank into the negative pressure range through the open vacuum limiter. When -10 mbar is reached, the vacuum limiter closes. If the tank is then emptied, the pressure drops further. At a pressure of -40 mbar, the vacuum regulator supplies nitrogen and keeps the vacuum constant.