Lids for Fume-Tight Tanks: What Are My Options?

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Poly Processing manufactures a wide variety of storage tank systems compatible with many different chemicals, including fuming chemicals that must be securely sealed when stored. For these chemical applications the use of a fume tight lid is usually required. Here’s a closer look at how a fume tight lid functions, when one might be required, and what options are available to meet your chemical storage needs.

Fume Management is Essential in Chemical Storage 

Most of the chemical storage tanks in use that Poly Processing manufactures are vented to atmosphere. That means that the lid is on, but isn't completely sealed. Instead, the tank's vent goes either straight to atmosphere or through a building out into the atmosphere.More corrosive or dangerous chemicals cannot be allowed to vent in this way because they are harmful if ingested or inhaled and can attack materials outside of the tank.That's why fume tight lids are used for some chemicals.

Hydrochloric Acid Must Be Sealed When Stored 

One example of a chemical that requires a fume tight lid is Hydrochloric Acid, a chemical used to lower the pH of water and as an emulsion breaker in industrial wastewater treatment. The lid is used to protect people and the environment from the harmful fumes and the chemical’s corrosive nature. If it were to leak in a building, for instance, it would eat away at the metal and other materials inside the building.

How Fume Tight Lids Work With Scrubbers 

A fume tight lid keeps chemical fumes from being vented out. Poly Processing accomplishes this by designing a tank with a vent line attached to a scrubber. The lid is sealed with a gasket system so that the fumes must go through the vent line.

Normally a base chemical or water is put into the scrubber so that as the fumes vent through it, they are then neutralized. Then the scrubber can safely vent out to the surrounding atmosphere.

Four Main Types of Fume Tight Lids 

There are four main sizes for fume tight lids that Poly Processing uses.

The 7-inch and 10-inch fume tight lid each thread on and are molded on smaller tanks. The 17-inch and 24-inch lids are sealed with chemical bolts with molded plastic heads. The bolts are available in stainless steel, Alloy C-276 and titanium. Gasket materials available include EPDM, Viton®, Viton® GF, XLPE or Buna. The 17-inch model is often used on 19-inch manways as well. Fume-tight manway cover is required for HCl applcations.

For more information on fume tight lids and which lids will work for your specific application, contact Poly Processing today.