Valves are tools that direct, control or regulate the flow of a fluid.
They can allow or interrupt the flow, regulate the flow or pressure rate and their body has inlet and outlet ports, inside of which there is a moving element for flow regulation or interruption.
In this video we’ll explain how butterfly valve works and watching videos in our playlist you’ll find out all types of valves around you.
For over ten years Jaes Company has been providing industrial spare parts and offers every type of valve from leading producers.
Butterfly valve gets its name from the shape of the plug and how it moves.
The plug is disc-shaped and the stem passing through it reminds of a butterfly. To obstruct the flowing, the disk make a 90° rotation on the normal axis to that of the piping run, like butterfly’s wings.
The flow comes to a full stop when the disk sealing presses against the seat on the inside diameter of the valve body. Most valves are soft-seated in elastomeric material against which the disk seals.
If the butterfly valve is designed for extreme conditions, it consists of two metal sealing rings, one on the plug and one on the seal seat.
The stem has no hermetic seals (that can be the stuffing box with some packing gland or O-ring seals), in order to avoid leakages contaminating the operating liquid or to impede that the liquid corrodes the interior mechanical parts of the valve.
The butterfly valve body construction varies in the ways they are joined:
- the double flanged valve: two bored flanges ensure a free connection of the flanged pipes by bolts.
- the Wafer-style valve: four centring through-holes allow to use the same bolts for both pipes;
- the Lug-style valve: multiple threaded centring bores secure the valve with several bolts and no nuts;
- the Butt-welding Ends: both ends of the valve body are welding-ready to be joined to the pipes.
The butterfly valve is a rotary motion valve, which means that 1/4 turn of the disk is enough to fully open or fully close the flow. This is also why it’s called fast-acting valve.
If the valve is big, it is actuated by a handwheel connected to the stem through a gear train increasing the torque and making the tightening easier at the expense of speed.
Instead of a lever or a handwheel many valves use actuators, that can be electromechanical (with an electric motor) or pneumatic actuators (with pneumatic piston).
Butterfly valve is well-suited for handling large flows of liquids or gases at relatively low pressures or at high temperatures, and for handling of slurries or liquids with large amounts of suspended solids. They are often used in water and even oil pipelines. They are also a common part in internal combustion engines, in both carburettor and throttle body, for regulation of air and mixture flow rate. Thus the position of butterfly valve determines the power of the engine.
To know more of how cars work, watch our videos in the playlist about car’s world.
Compared to ball valve, plug valve, gate valve and globe valve, butterfly valve has three main advantages: lower costs of maintenance, savings in weight and space. As a matter of fact, it is usually suited for big projects, that can highlight its qualities.
Here you can see an actual butterfly valve, easy to recognise by the plug shape; after watching the video could you guess the exact valve type?
Do you know how many types of valves we use every single day? Watch the videos in our playlist and will find out all types of valves around you.
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