Cast 319 aluminum blast gates are available in both half and whole versions, 2" to 22". Blast gates are used to either control a branch of a system, a run to a specific machine or for balancing. The collar of the whole gates are tapered to allow for a tolerance on the exact diameter of the duct. Half gates are usually used in a retrofit of a system where a 180 degree section is cut out of the duct and the collar is intended to straddle the duct.
Custom fabricated gates are available in carbon steel, stainless steel with rolled collars or angle rings according to your specification or ours.