Standard filter bags are typically manufactured with a metal ring, either galvanized carbon steel or stainless steel, sewn in the top of the filter bag Handles are also sewn in.

Another design incorporates a molded plastic top. These tops typically are polypropylene r polyester with the handles molded in. Various types of tops are available to fit specific manufacturers? housings.

The top can be sewn or welded to a sewn bag in one case or supplied in an all-welded construction with either glazed polyester or polypropylene felt in another option.

All-welded advantages include:

• There are no needle holes hence efficiencies are increased.
• No sewing thread is used resulting in the elimination of the possibility of silicone contamination due to thread.
• The glazed finish and fused edges of the bags greatly reduce or eliminate fiber migration.