Uniweld Nitrogen Flow Indicator NV1

The Uniweld NV1 is a nitrogen flow indicator used to verify purge flow during brazing operations.

Purging refrigerant tubing with nitrogen during brazing is standard practice, and the flow indicator confirms it is actually happening.

The purpose of the purge is to displace the air inside the tube while it is heated. Copper heated in the presence of oxygen forms a black cupric oxide scale on the internal surface. That scale is brittle, flakes off in service, and circulates with the refrigerant, where it blocks metering devices and strainers and contaminates the compressor.

The scale forms only on the inside, so a joint that looks perfect externally may have produced a substantial quantity of it.

The flow required is small. A gentle, continuous flow is sufficient to displace air, and excessive flow cools the joint, disturbs the flame, and can blow the molten filler out of the joint.

Judging that small flow without an indicator is difficult, which is the problem the tool solves. It gives a visible confirmation that gas is flowing and roughly how much.

An outlet must be provided for the purge gas to escape, otherwise pressure builds and no flow occurs regardless of the regulator setting.

Confirm the indicator suits the flow range and connections in use, verify flow before applying heat, and maintain the purge until the joint has cooled.

Brand

Uniweld

SKU

NV1

Category

Flow Indicators

Weight

1.1 lbs

Dimensions

7.50" x 3.50" x 2.20"

Price

$75.00

Availability

In stock

Rating

4.1 / 5.0