Hydropower seals - Import export

Servo motors in hydropower plants normally operate water hydraulically. These servo motors perform the functions of opening, closing and control of shutoff and regulating devices and must be able to maintain the setting position at any prevailing pressure.

Kaplan turbines are typically used for river power plants on calm waters. The blade angle runner blades (Kaplan blades) is adjustable. The pressure of the water flow, which is controlled by the guide vanes of the upstream wicker gate, can then be efficiently converted into energy. The bidirectional MANOY® system seal WP, type 444, in the form of a continuous ring was developed to protect the hydraulic adjustment device and prevent hydraulic fluid leakage. Type 449 is particularly useful for maintenance work because rather than being continuous in circumference, the seal is open and has a guide blade.

Penstocks are used to discharge the headwater from a reservoir. Due to thermal and dynamic effects on the pipelines which are usually run underground in the mountain, compensation for expansion is necessary. By fitting an expansion joint, slow creep movements, eccentricity, dilation and also pipe misalignment can be reliably absorbed. The MANOY® system seal WP, type 436, was specially developed for leakagefree operation of an expansion joint.

Spherical valves are installed upstream of the turbine as shutoff devices specifically for high pressures at the end of the penstock. Their main function is to close off the penstock during normal shutdown or load shedding of the turbine. The seal is a metal sliding ring which is generally moved by water hydraulics. The MANOY® system seal WP, type 434 (outer sealing) and the inner sealing type 439, were developed for sealing of the sliding ring. The profile dimensions can be customized for maintenance or specific requirements.

Pelton turbines are used in hydropower plants with a high head. The sealing system specifications are equally high.Control of the turbine output is infinitely variable from part to full load by adjusting the nozzle spear valve. The control unit for linear adjustment of the jet needle can be protected against water and silt infiltration by the MANOY® system seal WP. Types 466 and 486 (both inner sealing) were specially developed for these applications. Types 461 and 481 are for outer sealing configurations. In the context of design, types 481 and 486 must have a split housing. All versions can be supplied with customized profile dimensions for existing groove designs.

Pivot pins are found on shutoff devices such as spherical valves, butterfly valves, hollow jet valves and plunger valves. These valves are generally used for opening and closing and occasionally to control the flow rates by oscillating movement. The greaselubricated sliding bearing is protected against water infiltration by a seal on the inside. The seal also prevents the grease leaking into the inside to prevent water contamination. The MANOY® system seal WP, type 418, was developed for this application. To prevent leakage of grease from greased bearings, the unidirectional MANOY® system seal WP, type 456, is also installed.