The butterfly valve is a device to stop or regulate the flow of water into a canal, increasing or reducing the passage section by a plate called "butterfly" that swivels. By reducing the passage area increases the pressure drop across the valve, reducing the flow. This type of valve is characterized by a low pressure drop when fully open.

The butterfly valve is a device to stop or regulate the flow of water into a canal, increasing or reducing the passage section by a plate called "butterfly" that swivels. By reducing the passage area increases the pressure drop across the valve, reducing the flow. This type of valve is characterized by a low pressure drop when fully open.

This valve consists of a cylindrical body with two flanges at it sends that snap into the pipe, and a cover plate which seals off the water. These valves are often used generally lock closure in front of another regulator or in front of a central turbine. The valve body can be rolled or cast material and has two holes diametrically opposed to its bearings allow the shaft passes through the gland to prevent water leakage. This shaft is keyed to the cover plate in their rotation, which provides the mechanism makes opening and closing of the valve. The cover plate is shaped like a lentil, in case of being a Lenticular valve,  but hollow inside forming reinforced boxes, these efforts are attached to the front and back wall sand a cylinder that passes through the disc that houses the shaft which produces a shift to disk and it has to be 81 º.

The sealing is carried out by rubber bands around the outer disk, which are fastened with stainless screws that disk material and are attached to a ring located in the valve body, also of stainless material, when the disc is in position closed.

There are two types:

Lenticular valve

Valves biplane