Details

Introduction
Automated Hydraulic Control Valve Test Bench – Flow, ΔP, Leakage, Response & Hysteresis
In mobile and industrial hydraulics, a valve is not “just a component”—it’s the control authority of the whole machine. Flow metering accuracy decides whether an excavator feels smooth or jerky; leakage decides whether a system holds load safely; response time decides whether a closed-loop controller behaves or hunts; and pressure drop decides whether you lose power to heat instead of useful work. That’s why a serious valve test stand must do more than “make pressure and show a gauge”—it must reproduce real operating conditions, measure the right signals with repeatable automation, and produce records that engineering and quality teams can trust.
Neometrix’s Automated Hydraulic Control Valve Test Bench is built as a universal, automated test rig for validating a wide range of mobile sectional valves and industrial electrohydraulic/proportional valves, combining high hydraulic power, multi-channel instrumentation, and software-driven test sequencing with data logging. 

What makes this platform valuable for both production and R&D is that it supports the full lifecycle of valve validation: incoming inspection, calibration/tuning, performance characterization, endurance verification, and troubleshooting after field feedback—all using repeatable sequences and archived datasets. This is especially important when you need to compare valve-to-valve variation across batches, validate a new spool/sleeve combination, or prove compliance to a customer specification with test records that can be reviewed months later.

What this machine is designed to test
The platform is structured to support both mobile valve banks and industrial proportional / electrohydraulic valves, including (typical examples from the attached valve families):
Mobile valves
• CMA (Thor twin spool sectional valve system) 
• CLS180 sectional valve system / valve banks 
These valve families typically require multi-port routing, stable supply conditions, and the ability to validate behaviors that only appear when multiple functions interact (flow sharing, saturation, compensation stability). The platform is built to handle such complexity with structured procedures rather than ad-hoc manual testing.

Industrial valves
• SiCV (Screw-in Cartridge Valves) 
• Two-stage proportional electrohydraulic directional control valves (pilot + mainstage) 
• Electrohydraulic directional control valves for Size 3 and Size 5 formats 
Industrial valve testing typically emphasizes repeatable command/response characterization, fine leakage validation, calibration logic (including LVDT-based calibration where applicable), and clean dynamic response records. This stand supports those workflows through automation and robust data acquisition.

The result is one test platform that can cover:
• single valves (cartridge / subplate / proportional valves), and
• multi-section valve banks (1 to many sections), including the behaviours that only appear when multiple functions are active (flow sharing, compensation, saturation effects).

In practice, this means a single test installation can support multiple programs in parallel—production EOL checks for one valve family, while engineering runs deeper characterization on another—without rebuilding the entire test strategy from scratch.

With suitable fixtures and routing, the bench can be tuned for virtually any hydraulic control valve architecture—directional, pressure-control, and flow-control—covering cartridge, subplate, and manifold-mounted designs (including common variants such as relief, reducing, sequence, counterbalance/load-holding, and priority flow control valves).

Core test capabilities
This test stand is not limited to a single “pressure test”. It is designed for a broad mix of static, quasi-static, and dynamic validation, such as:
• Endurance testing (cycling under defined pressure/flow conditions) 
• Pressure drop testing across flow ranges 
• Hysteresis / command-to-flow behaviour 
• Leakage testing up to high pressure 
• Response time testing (dynamic step response) 
• Max flow verification 
• Pull-in current / drop-out voltage checks (electrohydraulic valves & coils) 
• Flow accuracy, flow sharing, and flow compensation tests (especially for sectional valves) 

Beyond the named tests, the platform’s value comes from how these tests can be combined into programmed sequences—for example: warm-up → bleed/flush → pressure-drop mapping → hysteresis sweep → leakage check → dynamic response snapshots → endurance cycling → post-endurance leakage and hysteresis comparison. That structure is what turns test data into engineering decisions.

For CLS180 valve banks specifically, the attached production test procedure includes structured steps like inlet pressure drop checks, metering performance with hysteresis curves, compensation validation by ramping pressures and monitoring flow stability, and internal leakage checks. 

High-level technical capability envelope
The platform is specified for high hydraulic power and broad operating windows so you can run both mobile and industrial valve protocols on one system.
Typical capability highlights
• Hydraulic supply capability referenced up to ~400 LPM and ~420 bar (application dependent) 
• Operating oil temperature window suitable for controlled repeatability during test execution 
• Filtration cleanliness reference aligned to production-grade valve testing expectations 

From a practical test-lab perspective, this envelope matters because it lets you test:
• low-flow fine metering behavior and higher-flow functional limits,
• mid-pressure behavior and high-pressure integrity checks,
• cold start behavior and temperature-stabilized repeatability (where viscosity effects are controlled).
This combination is especially important when your end customer expects consistent behavior across temperature bands and long duty cycles.

System architecture that enables “real testing” (not just pressurization)
1) Hydraulic power pack and flow generation
The stand is built around a multi-motor, multi-pump architecture so it can generate:
• high flow,
• stable pressure control, and
• repeatable ramps / profiles for dynamic tests.
This architecture allows the system to operate efficiently at different duty points—running smaller power stages for conditioning/low-flow tests, and scaling up for high-flow or high-load events. It also supports better stability in control loops, because the system is not forced to run at an extreme operating point for every test type.

Example configuration references include:
• Multiple main motors and secondary motors for staged power delivery 
• Multiple main pumps and secondary pumps (variable + fixed displacement) 
• Large reservoir capacity and high heat-rejection oil cooler to keep temperature stable during long runs 

2) Test area interfaces and plumbing flexibility
To reduce setup time and to handle different valve families, the rig provides multiple supply and work port arrangements 
This kind of interface flexibility matters for real operations because valve testing is fixture-driven: faster changeovers mean higher throughput and less risk of plumbing errors. It also helps when you’re testing different port configurations (P/T/A/B/LS/drain), pilot supply needs, or valve banks with section-specific routing.

3) Electrical drive and valve actuation support
Modern EH valves require more than “24 V DC” — they require correct current drive, PWM, CAN behaviours, and signal conditioning depending on family.. 
CLS180 testing references different actuation needs (EH controlled, hydraulic pilot, manual linkages, pneumatic actuation) depending on valve bank configuration. 
In practice, this ensures the bench is not limited to one actuation style. It can support electrohydraulic spools, hydraulically piloted stages, or setups where the actuator/control is provided externally but the bench performs controlled hydraulic loading and measurement.

4) Instrumentation, HMI, and data logging
The platform is designed around multi-channel measurement and logging—flow, pressure, temperature, command signals—so each test produces a time history that can be reviewed, plotted, and archived for QA traceability.
This is critical not only for R&D, but also for production: if a valve fails a criterion, you want a record you can inspect—was it instability, sensor drift, a plumbing issue, an electrical actuation anomaly, or a genuine valve defect? Proper logged traces make that diagnosis fast.

Typical test workflow on the stand
1.  Valve identification + fixture mounting
▹ Mount the UUT (single valve or valve bank) on the appropriate fixture/manifold.
▹ Connect P/T/A/B/LS and any pilot or drain lines as required by the valve family.

2.  Conditioning
▹ Warm up oil to the defined temperature range.
▹ Bleed / flush sequences (common in proportional valve protocols) to remove entrained air and stabilize measurement. 

3.  Conditioning is where a lot of “bad test results” are prevented. Air entrainment, unstable viscosity, and incomplete thermal stabilization can create false instability, noisy signals, and misleading leakage behavior. A disciplined conditioning step protects both the test result and the valve itself.

4.  Automated test execution
▹ Select the valve family / test procedure.
▹ Run automated steps (ramps, dwells, step commands, cycling) while logging data.
Automation matters because it enforces consistent ramps, dwell times, and command profiles—ensuring the same test today matches the same test next month.

5.  Result packaging
▹ Data saved with test metadata.
▹ Graphs exported for inclusion in final reports and customer documentation.
This step is where the stand becomes a production tool: consistent naming, consistent structure, consistent evidence packages—useful for audits, customer acceptance, and internal validation.

Test suite details (website-friendly, technical, and “reads interesting”)
Below is a catalog-style description of what the stand can run. I am intentionally not over-focusing on numeric limits inside each test description—the goal here is to convey variety and seriousness of validation while staying technically correct.
A) Pressure drop & flow characterization (ΔP vs Flow)
Purpose: Quantify energy losses through the valve metering path and validate whether a valve meets the expected hydraulic efficiency across flow ranges.
What the stand does:
• Sweeps flow through defined operating points
• Measures inlet/outlet/work-port pressures
• Builds ΔP trends and ΔP vs flow curves (for cartridge valves and directional valves)
• Enables comparison of pressure-drop behavior between valve variants, spool/sleeve options, and manufacturing batches
• Supports repeat runs at stabilized temperature to separate “true valve behavior” from viscosity effects







B) Hysteresis testing (command ↑ and command ↓ behaviour)
Purpose: Validate whether the valve responds consistently when approaching a target from increasing vs decreasing command (a major driver of controllability and “feel” in mobile machines).
What the stand does:
• Slowly ramps command from zero to max and back to zero
• Logs flow vs command and generates a hysteresis curve
• Helps identify sticky spool behavior, biased neutral, or friction-driven nonlinearity
• Supports “before/after” comparisons when tuning deadband, flow gain, or pressure gain
CLS180 procedures explicitly describe this style of hysteresis curve measurement during section flow metering performance testing. 





C) Max flow verification
Purpose: Confirm the valve reaches expected rated flow under specified command conditions (and identify incorrect spool/sleeve combinations or tuning issues).
Where it matters:
• Sectional valves (CLS180/CMA) where each section must meet its metering expectation
• EH valves where sleeve/spool combinations define rated flow windows
• Ensuring production consistency: a “small shift” in max flow often signals a real assembly or calibration issue

D) Leakage testing (internal and external)
Purpose: Leakage is not just a quality metric—it directly impacts:
• load holding safety,
• thermal efficiency,
• machine drift, and
• ability to meet neutral stability requirements.

What the stand validates:
• External leakage (assembly integrity under pressure)
• Internal leakage at work ports / critical seals (especially on valve banks)
• Leakage changes after endurance cycling (a strong indicator of wear or seal degradation)
• Neutral/position-specific leakage behavior (useful in fine control valves)


E) Response time / dynamic behaviour
Purpose: Determine how fast the valve reaches the commanded position/flow (critical for closed-loop performance and stability).
What the stand does:
• Applies step commands / shaped commands
• Measures flow/pressure response over time
• Flags sluggishness, overshoot, oscillation, or instability

• Provides evidence traces that support controller tuning decisions and field issue diagnosis


F) Pressure impulse / cycling tests
Purpose: Validate robustness under repeated pressure events and confirm stable behaviour across repeated cycles.
What the stand does:
• Runs programmed pressure impulses and cycling sequences
• Logs pressure/flow response and any drift over time
• Helps reveal weak points that steady-state tests can miss (seals, dynamics, recovery stability)
• Supports comparison of event-to-event repeatability (an important QA indicator)





G) Pull-in current & drop-out voltage tests (electrical behaviour under load)
Purpose: Confirm the valve’s electrohydraulic actuation behaves correctly—especially important for coils, drivers, and integrated electronics.
This is explicitly listed as a test capability in the manual. 
In production, these tests help quickly isolate whether an issue is hydraulic (spool friction, contamination) or electrical (coil characteristics, driver behavior, wiring/shielding). For field troubleshooting, pull-in/drop-out evidence often pinpoints intermittent electrical faults that would otherwise be blamed on hydraulics.



H) Flow sharing and anti-saturation behaviour (multi-section valve banks)
Purpose: This is where a true mobile valve test stand earns its keep. When multiple sections are commanded together, the system must:
• distribute flow correctly,
• maintain controllability, and
• avoid function “stealing” or instability.
The FAT procedure includes dedicated flow sharing / anti-saturation style evaluations (multiple sections at defined pressure drops and commands). 
These tests are especially valuable for:
• validating priority functions vs non-priority functions,
• confirming consistent behavior with combined demands,
• ensuring predictable machine motion under multi-function operation.





I) Flow compensation (pressure compensation stability)
Purpose: Validate that a section’s metered flow stays stable even as inlet or load pressure changes—critical for predictable machine motion.
CLS180 procedures include compensation validation by ramping pressures and recording flow variation. 
This is one of the most practical “real world” tests for mobile hydraulics, because it replicates what happens when an actuator load changes mid-motion. A good compensation curve means the operator feels consistency; a bad curve means jerks, stalls, or unexpected speed changes.



Supported valve families 
Here’s a simple “what the stand is intended to cover” summary using your attached valve documents:
• TP-CMA: EOL rig capability requirements for Thor twin spool sectional valve system (pressure capability, flow needs, UUT electrical supply). 
• TP-CLS180: production test procedure for CLS180 valve banks, including inlet tests, metering curves, compensation checks, leakage validation, etc. 
• TP-SiCV: sample cartridge valve test procedure including pressure-drop/flow relationship reference. 
• TP-873461: two-stage pilot valve EOL; includes valve description and test conditions. 
• TP-873462: two-stage main valve EOL; includes valve intro, test conditions, and procedures. 
• TP-873463 (Size 3) and TP-873464 (Size 5): EOL procedures for size-specific EH valves including LVDT flow calibration logic and sleeve/spool flow mapping. 

With suitable fixtures and routing, the bench can be tuned for virtually any hydraulic control valve architecture—directional, pressure-control, and flow-control—covering cartridge, subplate, and manifold-mounted designs (including common variants such as relief, reducing, sequence, counterbalance/load-holding, and priority flow control valves).


  

    
Parameter
    
Typical Specification / Configuration
  

  

    
System type
    
350 kW automated valve test stand for mobile and industrial valve testing
  

  

    
Max power consumption (reference)
    
~430 kW
  

  

    
Main electrical supply
    
3-phase, 440 VAC (reference)
  

  

    
DAQ supply
    
Single phase, 220 VAC (reference)
  

  

    
Operating fluid
    
Hydraulic mineral oil VG-32
  

  

    
Operating temperature window
    
~20°C to 75°C (reference)
  

  

    
Reservoir capacity
    
~1200 L
  

  

    
Cooling
    
Plate type oil cooler (reference)
  

  

    
Motors
    
Multiple main and secondary motors
  

  

    
Pumps
    
Multiple variable and fixed displacement pumps
  

  

    
Filtration (reference)
    
Pressure, return, and drain filtration as per manual
  

  

    
Test capability envelope (reference)
    
Up to ~400 LPM and ~420 bar (application dependent)
  

  

    
Valve families supported
    
CMA, CLS180, SiCV, two-stage proportional valves (pilot + main), size-3 and size-5 electrohydraulic valves
With suitable fixtures and routing, the bench can be tuned for virtually any hydraulic control valve architecture—directional, pressure-control, and flow-control—covering cartridge, subplate, and manifold-mounted designs (including common variants such as relief, reducing, sequence, counterbalance/load-holding, and priority flow control valves).