The eHydroCOM represents a generational shift in reciprocating compressor capacity control — from hydraulic actuation and bypass valves to all-electric, digitally controlled electromagnetic valve actuation. Traditional HydroCOM systems use hydraulic oil pressure to hold suction valves open; eHydroCOM eliminates the hydraulic power unit entirely, replacing it with an electromagnetic actuator mounted directly on each suction valve. A microprocessor in the actuator controls the electromagnetic coil with precise crank-angle-referenced timing, holding the suction valve open for exactly the portion of the compression stroke needed to reduce capacity to the process demand. No oil connections, no cooling water, no hydraulic maintenance — just power and a CAN bus communication cable.

How does the reverse-flow principle save energy compared to bypass control?

In a reciprocating compressor with bypass (recycle) control, the compressor always compresses 100% of its design capacity — the excess gas is simply vented back to suction through a recycle valve. This means the compressor consumes full power regardless of process demand. With eHydroCOM's reverse-flow principle, the suction valve is held open during the early portion of the compression stroke. During this period, the piston rises but gas flows backward through the still-open suction valve to the suction manifold — no compression work is done. The valve closes at the crank angle corresponding to the desired capacity, and only the remaining gas volume is compressed. At 50% capacity, approximately 50% of the compression energy is saved — a near-linear relationship between capacity reduction and energy savings that bypass control cannot achieve.

What distinguishes the XD variant from the HD?

Frequently Asked Questions

Can eHydroCOM be retrofitted to existing HydroCOM-equipped compressors?

Yes. The eHydroCOM actuator shares the same mounting footprint as the hydraulic HydroCOM actuator on the suction valve. The retrofit involves: removing the hydraulic actuator, hydraulic hoses, and HPU; installing the eHydroCOM electromagnetic actuator on each valve; mounting the FPSU/ePU power supply cabinet; and connecting the CAN bus communication cable between actuators, power supply, and the DCI/eCIU interface unit. The TDC sensor and compressor interface to the DCS/PLC typically remain unchanged. The primary site modification is removing the hydraulic infrastructure — oil reservoir, pump, filters, and cooling circuit — which frees floor space and eliminates an entire maintenance category.

What happens if power to the actuator fails?

The eHydroCOM actuator is designed fail-safe: without electrical power, the electromagnetic coil cannot hold the suction valve open. The valve reverts to its normal spring-closed position and the compressor runs at 100% capacity — the same behavior as a de-energized HydroCOM or an unloaded compressor with the unloading system disabled. This ensures that a control system failure does not shut down the compressor or the downstream process, though it does mean the process will receive full flow until the control system is restored.