Steam alone doesn’t actually penetrate quickly or kill the weed efficiently – that’s why you need saturated steam and boiling water to create thermal shock in the weeds.
Steam can be created at any temperature above the ambient atmospheric temperature. Think of a warm spa outside on a winter’s day. Steam vapour actually has very little benefit in weed control. Our first Steamwand in 1997 generated small volumes of hot water and steam. The hot water killed the weeds slowly and the steam was just vapour. It was too slow to ever become commercial.
Whereas, our patented method of delivering a depressurised mixture of saturated steam and boiling water (Satusteam©) at boiling point cooks vegetation utilising the principle of Thermal Shock.
Thermal Shock occurs by rapidly heating the weed by applying 98-100°C (212°F) water and or wet steam for just 0.1 seconds. This causes the cells to literally explode, cooking the exposed vegetation instantly. The thermal shock delivered at temperatures above 98°C / 209°F is 2-3 times more efficient than lethal heat (temperatures below 98°C) which hot water systems rely on.
The reason our system of killing weeds using Thermal Shock works so effectively is because water is brilliant at transferring heat. Think about it like this. Imagine you’ve turned on the oven to 300°C (572°F) and you put your arm in there. You’ll feel the heat instantly, but it’ll take a few minutes for it to actually start burning you. Now imagine pouring 100°C (212°F) water on your arm, it will burn instantly and deeply penetrate, blister, and you’ll need treatment.
Our wet steam or Satusteam© is delivered at low pressure, at the end of an insulated lance and hose; and doesn’t even splash on your boots; so it’s very safe for operators and anyone nearby, including the general public.
Whilst we haven’t dropped the legacy of our first named Steamwand machine, we don’t actually use steam. We use Satusteam®©.
Robin Proctor flattens weeds in Maui with Satusteam©