Flat tank or auto blow torches have a special fascination for me, I have seven of them ATM with one more arriving soon thanks to Papaw.
I don't know which company made the first flat tank torch, but Clayton & Lambert supplied the the US government with many thousands of gasoline torches. At the governments request they designed a special flat tank torch to fit in a government tool kit.
These were made by most torch manufactures and became known as auto torches, because of the popularity with mechanics, being narrow they where useful for working in cramped spaces in a automobile. They would also fit in tool boxes much better than the larger torches.

This is a Turner No. 418. One of my oldest flat tanks 1918. You can see the swing out stand to make the torch less prone to falling over.

Here's an Otto Bernz from around 1932, most older torches have the pump in the handle rather than the tank.
A Wall Mfg. Supply Co. 1950

The easy to spot Unique Mfg. Co. steel tank torch. 1947

Keep a look out for flat tank torches for me guys, especially those with pumps in the handles.
The older models will often have solder all around the bottom and top of the tank, this looks like a rather rough repair but the torch was made like this.
Cheers
Batz