Common failure modes in Hydraulic Flow Dividers

Hydraulic flow dividers can be described as the unnoticed heroes in synchronized movement. They ensure that motors and cylinders operate in unison, regardless of load fluctuations. However, as they are situated at a crucial junction within an electrical circuit, their failure could bring an entire process to a halt.

Understanding why these components fail and what causes them is essential to transition from repairs that are reactive to a proactive maintenance approach. Here are the most frequent failure mechanisms that can be found in both the spool-type and gear-type flow dividers.

1. Internal Bypass (Volumetric Inefficiency)

The most common issue encountered in flow divisors is the loss of synchronization due to internal leakage.

• The Sign: One cylinder or motor always lags behind the others, or the whole system is struggling to keep up when under a lot of pressure.

• The reason: Over time, the internal clearances between walls and gears (in the gear type) or spools, as well as the housing (in the spool type), increase because of wear. This causes liquid to "slip" over the mechanism instead of being weighed.

• A Culprit: Usually,y the cause is a contamination by fluids. Fine particles act as water sandpaper, which is used to scratch the surface of the machine and reduce the precision.

2. Mechanical Seizure

When the flow divider "locks up," it is often a devastating event for the device.

• The Signs: Total loss of flow to a branch or two, typically followed by a loud noise from the valves for relief or a sudden increase in pressure.

• The Reason: In a gear-type divider,s it is common for this to happen when a substantial chunk of debris gets inside the casing and blocks the moving elements. In spool-type separators, the spool can turn out to be "lacquered" or tangled up in one spot.

• The Culprit: High heat or chemical breakdown of the oil (varnishing). When the temperature of hydraulic oil is higher than its ideal operating temperature, the oil can leave an adhesive residue that binds precision components together.

3. Pressure Spikes and Housing Fatigue

Flow dividers are frequently subject to extreme pressure fluctuations, particularly in systems that have high-speed cycling.

• The Signs: External oil leaks or visible cracks in the housing of the divider.

• The Reason: Material fatigue. If the system has regular hydroshock (water hammer) or water hammer, the aluminum or cast iron part of the body may eventually experience hairline fractures.

• The Reason: Incorrectly set relief valves or the absence of accumulators that soften the pressure fluctuations. If the divider has been designed for 3000 PSI, but it is frequently experiencing fluctuations of up to 4,500 PSI and more, its life span will be reduced by 70 to 80 percent.

4. Cavitation Damage

Cavitation is known as the "silent death" of hydraulic systems. It is often undetected until the damage is massive.

• The Signs: An unusual "marbles in a blender" sound emanating from the divider. It also causes pitting on the metal surfaces inside.

• The Reason: If the inlet flow is limited or the liquid is excessively viscous (cold begins), there will be vapor bubbles within the oil. If these bubbles are moved to the high-pressure side, that is, the part divider falls in enough force to microchip the metal.

• It's the Culprit: Poorly sized inlet pipes, clogged suction strainers, or operating the equipment in extreme cold conditions without an appropriate warm-up cycle.

5. Uneven Load Intensification

It is less a problem of the component as such, but more of a problem with the circuit design, which can cause the destruction of the component.

• The Signs: Blown seals or ruptured hoses on a specific part of the division.

• The reason: If one cylinder is stopped mechanically and the other cylinders are moving, the flow divider continues to attempt to "push" fluid into the cylinder that is stalled. This could cause an pressure increasing effect, where the pressure inside that particular line is significantly greater than the output of the pump.

• A Culprit: Lack of individual port relief valves. Each flow divider circuit should at least have a relief valve at every outlet port to stop intensification from damaging the divider as well as the actuators.

If you think your flow divider may be failing, take a look at these three factors first:

1. Fluid Cleanliness Are the ISO particle count in line with the specifications of the manufacturer?

2. Casing Drain Flow For dividers made of gears, increasing the case drain flow can be an indication of a "smoking gun" to reduce internal wear.

3. Temperature Differential: Make use of an infrared thermometer. The divider, which is warmer than the rest of the circuit, could be affected by an excessive bypass.