Hydraulic efficiency: a holistic approach and stainless steel to reduce pressure drop
True hydraulic efficiency is never a matter of a single component. A hydraulic system is a complex network in which every element significantly influences performance, energy consumption and long-term reliability.
One of the primary goals of a well-designed system is the reduction of pressure drop. Pressure drop represents a loss of pressure caused by the resistance the system opposes to fluid flow. It is divided into:
- distributed losses, caused by fluid friction along the pipework;
- localised or concentrated losses, generated by valves, bends, fittings, filters and other accessories.
In both cases, pressure drop requires higher operating pressure and therefore higher energy consumption by the pumping systems.
The key role of valves in system efficiency
One of the most effective tools for assessing the impact of valves on hydraulic efficiency is the flow coefficient Kv.
The Kv value indicates the water flow rate (m³/h) that passes through a valve generating a pressure drop of 1 bar between inlet and outlet. It is therefore a parameter that relates two fundamental quantities: flow rate and pressure drop.
The relationship linking these elements is:
Kv = Q / √ΔP
where:
- Q is the flow rate in m³/h
- ΔP is the pressure drop in bar
Using this formula it is possible to compare valves of different sizes, types and construction characteristics, identifying the one best suited to the system.
The Kv value does not depend exclusively on the nominal diameter. For the same size, valves with more efficient geometries can offer lower pressure drop and therefore higher flow coefficients.
A valve designed with optimised hydraulic geometries reduces localised pressure drop, lightening the workload of the pump and lowering energy consumption and improving the energy efficiency of the system.
The Idrja check valves are a perfect example of design oriented towards hydraulic performance, thanks to:
- wide and smooth flow passages;
- reduced friction;
- thin wall sections;
- high-quality TIG welds.
The product philosophy developed for hydraulic efficiency in valves has also guided Mondeo in the manufacture of stainless steel manifolds. Thin wall sections and TIG welding limit pressure drop and contribute to the optimisation of hydraulic circuits.
This naturally applies to stainless steel hydraulic fittings as well, since this material allows high-quality machining and clean, smooth, irregularity-free internal surfaces that correspond to a fluid and consistent flow.
Pipework also makes a difference
Pipe sizing directly affects distributed pressure drop:
- undersized pipes increase fluid velocity and friction;
- oversized pipes entail unnecessary costs and space;
- non-optimised bends, joints and reducers generate additional turbulence and resistance.
Correct pipework design:
- reduces the pressure required of the pump;
- optimises fluid velocity;
- limits noise and water hammer;
- contributes to lower energy consumption and more stable operation.
Frequently asked questions about pressure drop
How can pressure drop be reduced?
The energy efficiency of hydraulic systems requires careful design that considers both distributed and localised pressure drop. To reduce localised pressure drop it is important to choose valves that, for the same size and type, have a higher flow coefficient.
How much can be saved with efficient valves?
Using valves that ensure low pressure drop allows energy savings of up to 20%. Evaluating the flow coefficient also enables correct valve sizing and is therefore part of the overall hydraulic circuit optimisation; it should also be noted that stainless steel valves, in addition to guaranteeing low pressure drop, are very long-lasting, which helps reduce replacement and maintenance costs.