Overview
This page describes the upper windcatcher box used to feed air into the ember detector intake system.
The purpose of the box is simple: it takes wind from any direction, turns that airflow downward, and sends it through a duct into the lower detector box, where the detector samples the moving air for embers, ash, smoke, or hot particles.
The system is designed to improve sampling under outdoor conditions by actively gathering and directing airflow instead of relying on embers or smoke drifting passively past the detector.
{This text and attachments were generated after interaction by CGPG 5.2}
System layout
The intake system has two boxes:
- Box 1: Windcatcher box The upper box. This has four side openings and contains the internal funnel and baffles.
- Box 2: Detector box The lower box. Air from Box 1 travels down through ducting into this box, passes through the detector zone, and leaves through a lower outlet or light trap.
Key dimensions and features
| Item | Value / description |
|---|---|
| Internal box size | 430 mm wide x 230 mm deep x 190 mm high |
| Number of side apertures | 4 |
| Aperture size | 150 mm wide x 60 mm high |
| Aperture position | One centred on each face, with top edge 15 mm below the top of the box |
| Funnel top opening | 300 mm x 150 mm |
| Funnel bottom opening | 115 mm x 57.5 mm |
| Funnel vertical drop | 110 mm |
| Funnel construction | 4-panel riveted aluminium funnel |
| Internal baffles | 4 local baffles, one behind each aperture |
| Ducting | Flexible all-metal aluminium duct, arranged as an S-bend to the detector box |
How it works
Wind enters through one or more of the four side openings. Just behind each opening is a small angled baffle plate. These baffles perform three functions:
- they reduce straight-through cross-drafts,
- they turn the airflow downward,
- they direct the air toward the central funnel.
The funnel then collects that air and narrows it into the outlet below. From there the airflow passes through the duct into the lower detector box, where the ember detector samples it.
Because the box has four openings, it does not depend on the wind coming from one exact direction. Whichever face is windward can admit air, and the baffles and funnel then guide that air into the detector path.
Main fabricated parts
The windcatcher box contains:
- four side apertures cut into the box walls,
- four internal baffles riveted behind those apertures,
- one four-panel tapered funnel made from sheet aluminium,
- one lower duct outlet connection leading to the detector box.
The funnel is made from:
- two Panel A parts
- two Panel B parts
These are riveted together along their seam tabs to form the complete tapered transition.
Assembly summary
Assembly is straightforward.
- Mark and cut the four side apertures in the aluminium box.
- Cut the four baffles from sheet aluminium using the templates.
- Rivet the baffles inside the box behind the apertures so they slope inward and downward.
- Cut the four funnel panels using the full-scale templates.
- Fold the seam tabs and rivet the funnel panels together in the numbered order shown in the assembly pack.
- Place the completed funnel centrally inside the box above the lower outlet.
- Support the funnel using the outlet collar, brackets, or straps as required.
- Attach the flexible duct below and route it down to the lower detector box.
The funnel does not reach the side walls of the box, so it is not intended to be riveted directly to those walls. It needs its own support arrangement.
In simple terms
This device is a wind-fed air collector for the ember detector system. It is intended to:
- accept wind from any direction,
- reduce straight-through drafts,
- turn air downward,
- concentrate the flow through a funnel,
- and deliver that air to the detector chamber below.
It is therefore a practical sheet-metal intake system designed to improve the reliability of ember or hot-air detection under real outdoor wind conditions.
Fabrication files
The following fabrication documents are available:
If these files are stored elsewhere on the site, replace the links above with the final URLs or PmWiki attachment paths.
Notes
- Print templates at 100% actual size.
- Do not use Fit to page.
- Check the calibration line before cutting material.
- The detector-side duct interior may be darkened with matte black paint to reduce reflections.