How a balancing valve works

Balancing valve is designed to create and maintain a fixed hydraulic resistance in water heating systems and water distribution networks for heating, cooling, or water supply.

Creating hydraulic resistance is usually necessary to balance (properly distribute the fluid) according to the needs of each branch of a branched network.

Static balancing valves are used only in systems with a stable and unchanging hydraulic mode. That is, in systems where the water flow rate [m³/h] remains constant throughout the entire operating cycle.

The operating principle of the balancing valve is based on reducing the flow passage for the fluid moving through the pipeline. Balancing valves are manufactured based on either a ball valve or a globe valve. The most common are balancing devices based on the globe valve. The operation of a globe-type balancing valve is explained on this page.

The operation principle of the balancing valve is based on changing the flow opening by the shutter-seat pair. A threaded stem is located in a plane perpendicular to the pipeline axis, with a shutter pivotally fixed on it. The shutter's plane is parallel to the pipeline axis. Inside the valve body, a fixed threaded nut is provided, forming a pair with the stem.

Turning the adjustment handle transfers torque through the stem and the fixed threaded nut, converting it into linear movement of the shutter, which moves from the fully closed to the fully open position. In the fully closed position, the shutter tightly presses against the seat in the valve body, hermetically blocking the flow.

Depending on the operating medium parameters, tight flow shut-off by the balancing valve is achieved by sealing between the shutter and seat using PTFE or rubber rings, or in a metal-to-metal design.

Changing the flow opening affects the valve’s hydraulic resistance – the flow capacity (Kv) of the balancing valve changes. The relationship between flow capacity and shutter position is given in the technical specifications.

The main difference between a balancing valve and a shut-off valve is that the balancing valve can operate in an intermediate shutter position, whereas a shut-off valve should be used only in fully open or fully closed positions.