SEALS FOR VALVE SHUTTERS OF HYDROELECTRIC SYSTEMS

Scenario

In large dams, hydroelectric plants the flow regulation is governed by cone or spherical valves. Their correct work is essential for the regulation of the entire system, as any operating problems can also cause a stop in electricity production with serious consequences.

Challenge

An ATP’s customer, leader in the construction of hydroelectric plants,  designing a new conical valve asked us to study a seal for the shutter. In particular, the seal had to be able to maintain reliable operation and low friction conditions, even in case of big seals and therefore large contact surfaces.

Solution

First of all, the ATP technical team analyzed the application and organized a team for the co-design with the customer, so that in the development of the solution both the specific knowledge of the control valves and of s and seals and plastic and elastomeric materials could be capitalized.

TECHNICAL DATA:

• Pressure: from 0.5 to 30 bar
• Stroke: 12mm
• Fluid: filtered river water
• Seals dimensions: 1150

Analyzing the operating characteristics of the valve, friction reduction and management (control) resulted to be conditioning parameters. The dimensions of the gasket determined large sliding surfaces which generated high friction that needed to be reduced as much as possible. Also due to the large size it was very expensive to create a test bench to test the forces generated in the application.

Thanks to the FEM analysis, our designers were able to test the different profiles and in this way

Optimize the sizing of the seal taking in consideration the frictional forces

Calculate the friction forces generated at defined pressure levels.

The theoretical calculation of the sliding surface has made it possible to calculate the probable friction forces generated and therefore to size the actuation of the valve shutter.

The seal was made of SINTEK HTPU, a special anti-abrasion polyurethane that allows a long operating life of the gasket and excellent resistance to breakage, even in the presence of not completely filtered water.

Testimony

«“We are very satisfied with the result obtained, in the field test the frictions reacted exactly as the FEM analysis predicted“. Customer’s Technical Designer

Consult our general catalog for the recommended materials depending on the operating conditions.