Dear boulfiza,
The only difference that in case of Gate valve you can open the valve gradually and you can use it as partly opened valve but in case of ball valve you can open it with quarter turn (90°) – it may cause Water Hummer -, Ball valve its not recommended to use as partly opened valve...
Check "The Chemical Engineer's Resource Page"
www.cheresources.com
or www.cimberio.com an Italian Valve Manufacturer for the Types of Valves, For any specific questions please contact me at: eyadhamideh@yahoo.com
Thanks
Hi
there is a special tools for that cleaning called Pneumatic Descalers with stiff extensible rods for heat exchanger tubes.
for detals pls visit www.mausitalia.it
With Best regards