Definition

A steam distribution arrangement of many parallel dispersion tubes on a common header; gives a short absorption distance in wide sections and short straight ducts (example: Neptronic Multi-Steam™).

Detailed Explanation

A steam distribution rack (multi-tube manifold) is a distribution arrangement made of many parallel dispersion tubes connected to a common header. Because it injects steam through many tubes spread across the section, it gives a much shorter absorption distance than a single-tube distributor. In the Neptronic range this arrangement corresponds to the Multi-Steam™ SD/HD/HDR (vertical tubes on a header) and, for the SKD, the jacketed Multi-Tube and the Mini Rack for reduced duct height. All are custom-built to the duct or AHU size.

Why It Matters

In wide or tall sections a single distributor concentrates steam in one region, the plume lengthens and part of the duct is under-humidified. Multi-tube distribution solves this: (1) even steam distribution across the section, (2) a smaller plume from each tube and a short absorption distance, (3) feasibility in air handlers with little straight duct after the distributor. Per manufacturer data, Multi-Steam™ has an absorption distance under 1 m.

Practical Example

In a wide air handler with only a short straight section after the distributor, the plume from a single-tube distributor can reach the first filter. A Multi-Steam™ built to the AHU size is used instead; steam is injected through vertical tubes spread across the section and, per manufacturer data, the absorption distance falls below 1 m. Tube count and spacing are set by the manufacturer from steam flow and section.

Engineering Note

The Multi-Steam™ is centred side to side in the duct or across the coil face of an AHU; the header comes pitched towards the condensate outlet from the factory, so the bracket only needs to be level. A sealed duct section or drained drip pan beneath it is recommended against water damage. The condensate outlet is connected to drain through an S-type trap whose height exceeds the system static pressure by at least 51 mm (Neptronic Multi-Steam manual).

NKT Application Link

NKT supplies Neptronic Multi-Steam™ and SKD multi-tube distributors together with SKE4, SKS4 and SKD humidifiers, and supports distributor selection from duct dimensions and air data.