Brownell is back with the ideal solution to protect fluids particularly sensitive to moisture contamination, such as brake fluids and transformers oils. Presence of water vapour in the air leads to condensation, which modifies the fluid properties, as the boiling temperature, considerably decreasing its performance. Depending on the fluid chemical composition and on the ambient temperature, moisture can also cause corrosion problems and formation of ice. But tanks must also be protected from overpressure and vacuum conditions generated by warming/cooling cycles of the fluid inside the tank and emptying/filling operations. In order to prevent the pressure build-up, the tank must be vented.
Tank Vent Dryers can be simply installed with a direct connection to an existing breather or vent pipe and, as the name says, operates in two different modes allowing the tank to “breathe” while protecting its content from external contamination.
During emptying, air is drawn into the tank passing through the desiccant contained in the main body of the Tank Vent Dryer. This forced path prevents water and other contaminates to reach the content of the tank. In addition, the outlet vent cover located on the top of the mounted bracket allows gas to exit preventing build-up in pressure following filling operations.
Extra precaution might be observed in order to achieve pressure equalisation by installing pressure relief valves on the connecting pipe.
A later version of the Tank Vent Dryer (Extended Life) includes a user adjustable atmospheric bypass control in the design.
The normal function of the valve disc is to raise when the internal pressure exceeds the operating pressure, as it can be seen in the picture on the right.
The bypass control allows to raise or lower the valve disc, thus regulating the amount of atmospheric air that mixed with the dry air that has passed through the desiccant before entering the tank. This operation will prolong the life of the desiccant while regulating the relative humidity level.
The Extended Life version of the Tank Vent Dryer is ideal when filling/empting operations are conducted on the tank at frequent intervals.
Tank Vent Dryer proved to be an extremely versatile product.
Available in various configurations, materials and size, it can be wall mounting (models 605, 610 and 615) or floor mounted (models 620, 630). The main body is available in mild steel or in stainless steel indicated for more aggressive environments. In addition, this product is suitable for tanks of considerable size, with a capacity up to 500,000 litres.
Tank Vent Dryer can be filled with a variety of adsorbent products according to the customer requirements, including silica gel Envirogel and molecular sieves.
Envirogel can adsorb moisture up to 30% of its weight and the desiccant colour change from orange to green is a clear signal that the desiccant is saturated and need to be replaced. A UV stabilised polycarbonate clear window installed on the body allows visual reading of the saturation level of the desiccant and a label located on the window indicates when the desiccant should be replaced.
Molecular sieves instead are suitable for those applications in which very low dewpoints are required. It adsorbs moisture up to 20% of its weight and has high adsorption efficiency at high temperatures. Molecular sieves, due to their formation, can selectively adsorb moisture and other contaminates. Due to the fact that no colour change occurs when molecular sieves are saturated, this version has a humidity indicator card fitted on the window of the desiccant container in order to provide similar visual colour change indication available for silica gel.
When the desiccant is saturated, it can be easily replaced by simply removing the desiccant holder. The desiccant can be replaced or reactivated and Brownell offers specific Refills Packages available for every model.