Near-Zero-Water Blackening System

The In-House Tru Temp black oxide system from Birchwood Technologies is deisgned for metal finishers facing water restrictions. According to the company, finishers can operate the system using almost no rinse water via the Near-Zero water recycler that re-uses the rinse water in the process line, reducing water consumption by 99 percent. This capability enables black oxide finishers in water-restricted areas to continue critical metal finishing operations while observing tight water usage guidelines. The recycler can be installed on a new Tru Temp line or into an existing line as a retrofit.

According to the company, a normal 100-gallon Tru Temp line with three flowing tanks, each using approximately 2 gpm of water, would consume approximately 63,000 gallons when operated for one shift per day for one month. With the Near-Zero system, the rinse water could be recycled and reused in the process tanks for approximately one month before changing the media filter and changing the water, the company says. A 100-gallon size tank line would require approximately 600 gallons of water each time the system is purged.

The Near-Zero system is designed for Tru Temp process lines with tank sizes ranging to 200 gallons and is pre-engineered for fast setup. According to the company, the system can be integrated into most tank lines in only a few minutes.

The Tru Temp in-house process produces mil spec/RoHS-compliant black oxide finishes with a 30-minute application time. The bath operates at 200°F and forms a non-dimensional, quality black magnetite finish on all types of tooling and machined components. Because the process uses a short cycle time, it streamlines part movement, improves control of finished part inventory and enhances ISO accountability, the company says.