Engineering solutions provider BMG, which distributes hydraulic valves manufacturer Hydraforce’s range of proportional valves in Southern Africa, works closely with Hydraforce engineers and customers in diverse industries, to design and manufacture customised hydraulic control solutions.

These solutions enhance performance, value and durability of mobile equipment.

“A thorough understanding of the latest fluid power technologies is critical for the design of efficient and cost-effective hydraulic sysXVtems. Coupled with technical expertise, is the need for the selection of high-performance valves and controllers, which must be installed and supported by a team of hands-on specialists,” says BMG fluid technology and high pressure divison product manager Ryno Landman.

He states that BMG supplies a range of HydraForce electro-proportional valves which is suitable for use in many applications in the agriculture, construction, materials handling, fluid conveyance, mining and quarrying sectors.

“Hydraforce hydraulic cartridge valves and controls are subjected to rigorous field testing and are proven for dependable operation in heavy-duty conditions. Efficiency, response times and signal integrity are optimised using Pulse Width Modulation (PWM) digital signal logic,” explains Landman.

PWM works by pulsating direct current and varying the amount of time that each pulse stays on, to control the amount of current that flows to a device. PWM is digital, which means that it has two states – on and off.

“The main advantage of PWM is that power loss in the switching devices is negligible. When a switch is off, there is virtually no current and when it is on and power is being transferred to the load, there is a minimal voltage drop across the switch.”

BMG’s range of Hydraforce proportional valves includes flow control and pressure compensating flow regulator valves, directional control and pressure control valves, with a focus on proportional control.

According to BMG fluid technology specialists, unlike directional control valves, which allows full flow when energised, proportional control directional valves control flow proportional to an electrical input signal. In pressure regulating or limiting valves, this signal corresponds to a pressure setting.

Proportional valves provide a change in output pressure or flow in the same ratio as the change in the input signal. For example, a 4 mA to 20 mA input signal may correspond to a 50 bar to 200 bar pressure setting. If the input signal is 4 mA, then the output pressure setting will be 50 bar. As it gradually increases to 20 mA, so too does the pressure setting increase to 200 bar.

This feature offers machine cycles, which are safely operated at greater speeds, with controlled start and stop characteristics.