TDR vs near-infrared moisture measurement
Near-infrared sensors are non-contact, extremely fast and completely unaffected by abrasion, because nothing touches the material. That is a real advantage. The trade-off is that NIR reads the surface.
Surface layer vs material volume
NIR measures by reflecting infrared light off the material and reading the response. Light does not penetrate far into wet sand, so the measurement describes the surface it illuminated.
TDR sends a guided electromagnetic pulse through the material adjacent to the probe and reads it in layers. The portable SONO M1 reads through roughly a litre of material rather than the face of the pile.
On free-flowing material falling off a belt, the surface is continuously renewed and the gap narrows. On a stockpile, in a bin, or anywhere material sits, surface and bulk moisture diverge — and it is the bulk number that goes into your mix.
Where each one wins
The material is moving and thin
Falling streams, thin belt layers, and processes where you cannot mount anything in contact with the material. No wear, no head replacement, no mechanical intrusion. Also the right answer where the material would destroy a contact probe.
The material sits, or you need a handheld
Stockpiles, bins, silos, hoppers and mixers, where a surface reading will not represent the bulk. And any application needing a portable spot check — there is no non-contact way to measure the inside of a pile from a handheld.
Comparing a NIR quote against ours?
Send it over. If NIR is genuinely the better fit for your installation we will tell you — we would rather lose the order than have you measuring the wrong thing.
Houston, Texas · Most quotes answered within one business day