Needle valves | Slide valves | IPH (Indian Pneumatic & Hydraulic)

IPH Bypass Valves for Hydro Turbines

Bypass valves are an important component of the MIV bypass line in a Hydroelectric turbine setup. They are used to equalise the upstream-downstream pressure for opening the main inlet valves, and is a critical application.

Initially designed primarily as an import replacement, our valves are now in use for the past 25+ years at various hydropower plants in India and all over the world.

There are two main types of valves manufactured by us, Slide valves and Needle valves. Out of these, being the newer technology, Slide valves are nowadays preferred. The is partly due to the stainless steel construction with inbuilt servomotor, as well as the ability to safely manage very high water heads of 1000-1100 meters. A brief description is provided below :

Type 1 : Slide valves for Hydro turbine main inlet valves (MIV/PPV - Spherical/BFV )

IPH Slide valves are compact stainless steel valves, with a body-integral hydraulic servomotor, as well as a straight-through flow path.

It is used for dissipating the kinetic energy of the water flowing at high velocity through the penstock, resulting in the equalisation of water pressure at both ends of the MIV, for safe MIV opening.

These valves are manufactured with finely machined seats, ensuring zero leakage through the metal-metal contact sealing. A robust design ensures high performance, with our valves active in projects with 1000-1100 meters water head, previously possible only by importing valves at a very high cost.

Multiple design choices are available, chosen based on site conditions such as high silt or high acidity etc, as well as other options such as those based on economic considerations.

Contact us for designing such Bypass valves, which are installed in hundreds of Hydro-electric projects around the world. We also carry out repairs of OEM valves, where feasible

Type 2 : Needle Valves (Angular flow) for Hydro turbine main inlet valves (SPV/BFV)

Angular flow needle valves are a legacy design, used in many projects installed decades ago. They are generally suitable for low water head applications, and are now superseded by slide valves.

IPH needle valves have an angular flow path, with a separate hydraulic servomotor used to drive the needle stem. Depending on flow velocity, the angular path can be between 90 to 150 degrees.

These valves have a cast housing, with an adequate inner chamber for optimal spread of the water energy. Along with a bottom energy dissipater plate and finely machined valve seat, this ensures a good metal-metal seal. Mounted separately on top of the valve, the hydraulic servomotor is relatively easy to service.

Metal seats are offered in both removable and in-body options, depending on flow parameters, silt content etc. Servomotors are optionally offered with spring force

We also carry out repairs of needle valves, with reworking/reinstallation of valve seats, along with servomotor reconditioning.