Flow divider – supplying two circuits with just one pump

The flow divider is used for the efficient distribution of pressures and flows. The purpose of the flow divider is to split a volumetric flow into different partial flows. Conversely, the component can also be used to combine different volumetric flows back into a single flow. This is why these components are also referred to as flow dividers/combiners.

Purpose of the flow divider

The main task of the flow divider is to reduce the number of pumps required. This lowers the costs for the setup and maintenance of a hydraulic system. Especially in serially manufactured systems, their use contributes to a significant reduction in production costs and provides a competitive advantage, as end customers can expect lower maintenance and repair costs.

Types of flow dividers

Two design types are available for flow dividers:

• Piston flow divider
• Gear flow divider

The piston flow divider is technically relatively simple. It is a branch piece without additional technical components. The volumetric flow is fed in on one side and is distributed via various openings into the branch lines. In the process, pressure or flow velocity is lost in the volumetric flow.

The rotary flow divider, usually designed as a gear flow divider, is technically more complex. This component has a small gear pump inside that helps maintain the pressure and flow velocity of the incoming volumetric flow.

Compared with a standard gear pump, there are two differences. First, the rotary flow divider only compensates for a pressure loss and can therefore be significantly smaller and thus more cost-effective than a conventional hydraulic pump. Second, rotary flow dividers also have multiple outlets, so pressure compensation and splitting of the volumetric flow take place within a single component.

Design structure of flow dividers

Piston flow dividers generally have only two outlets and consist of a robust housing made of hardened steel or aluminum, depending on the pressure the system is to be subjected to. In theory, multiple piston flow dividers can be connected in series to increase the number of outlets; however, this continuously reduces pressure and flow velocity.

Rotary flow dividers maintain pressure and flow velocity, are adjustable, and can be equipped with up to eight outlets. They are required when the incoming volumetric flow must be distributed to multiple partial flows without change. Despite their higher technical complexity, rotary flow dividers are robust and resistant to contamination. They are very efficient, but cost considerably more than a piston flow divider.

Applications of flow dividers

Flow dividers are used in large, complex hydraulic systems where only one or very few hydraulic pumps have to supply many actuators.

Because they distribute the volumetric flow evenly, the same pressure and the same flow velocity are present at every point in a hydraulic system. Based on this constant value, these parameters can be precisely controlled at specific points by using pressure-reducing valves or shut-off valves.

Construction machinery, especially excavators, wheel loaders, material handlers, or telehandlers, often has to operate multiple actuators. Slewing gear, drive, lifting gear for the boom, the tool opening mechanism, or cab lift hydraulics are usually operated by the same hydraulic system. Here, a flow divider can help keep the number of hydraulic pumps as low as possible. This reduces the overall system costs.