The difference between handle operated butterfly valve and worm gear operated  butterfly valve

Question: Hello, Bundor Valves, I need to purchase several butterfly valves, for water passing, pressure 10 kg, size DN50, skilled workers recommend me to use handle operated butterfly valve and worm gear operated  butterfly valve, I now know that the price of them is different,  the price of the worm gear operated butterfly valve is higher. I would like to ask, apart from the price, what is the difference between the handle operated butterfly valve and worm gear operated  butterfly valve?

Answer: The difference between the handle operated butterfly valve and worm gear operated  butterfly valve is mainly in the driving method, and some differences in use due to different driving methods.
The handle operated butterfly valve uses the handle rod to directly drive the butterfly plate to open and close, and the switch is quick but laborious. The worm gear operated  butterfly valve passes through the gear drive to butterfly plate. Although the switch is slower, it saves effort.
Therefore, if the pressure in the pipe is high, the operation of the handle operated butterfly valve is particularly laborious. Worm gear operated butterfly valves are commonly used in engineering. In addition to labor saving, the worm gear operated butterfly valve has a longer service life than the handle operated  butterfly valve in an environment with high switching frequency.
The handle operated butterfly valve is generally used in small-diameter pipelines, because the small-diameter torque is smaller, the opening and closing is relatively labor-saving, and the cost is also low. When the stem torque is greater than 300N.M or the diameter of the butterfly valve is greater than 200MM, it is more suitable to use a worm gear operated butterfly valve.