Question: What are the high performance valve and its features and application?

Answer:   The conventional butterfly valve is rubber lined concentric butterfly one used only at low pressure (<1.6 MPa). Its disk axis is at the center of the flow passage and seating belt. This kind of valve is sealed by jamming the rubber seat between disc and body under the action of external force. This sealing is usually called enforced sealing. The defects are :

1. Difficult to control the sealing pressure ratio;
2. Too much of wear and short service life.
3. Low operation pressure .
4. Limit applicable media, as water, gas and oil .
5. Big torque.

Originated from space technology, the high performance butterfly valve was developed in 70s, its features are:

1. The disc rotation center is offset from axis of pipeline and the sealing plane, which makes the disk being swung out upon opening, thereby eliminating the usual wear points at the top and bottom of the valve seat.
2. The seat of the HP butterfly valve, such as SNJ’s is of flexible lip type design, which uses the fluid sealing principle to attain reliable sealing, thus completely different from the enforced sealing principle of the conventional butterfly valve.
3. Long service life( up to 1 million cycles reached in testing) ; Low torque (about 30% lower than the conventional butterfly valve’s); higher operation pressure(to 10 MPa) ; and wide range of applicable media.

Invention of this kind of butterfly valves opens up possibilities for replacing gate valves with butterfly valves in a greater range of pressure service. With only one third of the weight of gate valves, about two thirds of the price of the corresponding gate valves, HP butterfly valves will surely have a bright future in the industrial field.