The Case Drain Filter Dilemma

CA50A recent arrival on ‘Planet Brendan’ who works for Bosch Rexoth’s ‘Large Hydraulic Drives’ division in Sweden (a.k.a. Hagglunds division) wrote me this after reading my “6 Hydraulic Mistakes….” report:

“I would have liked more information on why you shouldn’t have filters on the drain line on piston pumps. We actually use that solution in our drive units and we … Read more

Hydraulic Accumulator Maintenance, Testing and Recertification

Bladder and diaphragm accumulatorGas-charged accumulators are a common feature of modern hydraulic systems. They carry out numerous functions. These include energy storage and reserve, leakage and thermal compensation, shock absorption and energy recovery. But while accumulators present a number of advantages in hydraulic system operation, and can provide many years of trouble-free service, they are a maintenance item.

For example, the correct gas … Read more

Is it OK to Connect Supply Voltage to a Proportional Valve Coil?

FTDRE-prop-press-reducerOne of our members wrote me this question:

“One of our customers has a new wheeled excavator. The auxiliary circuit on this machine is controlled by an electronic proportional foot pedal which sends its signal to an ECU. This ECU then sends a variable voltage to 2 proportional solenoids located on the auxiliary circuit sandwich on the main DCV. But … Read more