Here more links about soviet flamethrowers on tanks with good photos
T-26 different variants
https://tanks-encyclopedia.com/ww2/s...chemical-tanks
BT tanks
http://forum.worldoftanks.eu/index.p...weapon-setups/
https://en.topwar.ru/173655-himicheskij-tank-hbt-7.html
Soviets before war sometimes created not specialised tanks but a regular with gun with special flamethrower as a addition with small tanks on mud breakers.
This installation was able for a few short bursts and installed on BT tanks instead of MG in hull. This tanks wasn't even consider as a specialised tanks. They were normal tanks in units with optional extra installation like OT-7 from picture.
Don't forgotten also about second type of use for flamethrower tanks they were used for build smoke screens to cover other tanks by soviet. So flamethrower can easy produce smoke instead of flame.