Contamination Control Contamination Control in in Dynamic - - PowerPoint PPT Presentation

Contamination Control Contamination Control

in in Dynamic Operating Environments Dynamic Operating Environments

Charlie Juhasz Charlie Juhasz Technical Director Technical Director Scientific Services Scientific Services Inc. Inc. SSI SSI

Why Contamination Control ? Why Contamination Control ?

Contamination determines life cycle cost Contamination determines life cycle cost

  Wear rates, service life

Wear rates, service life

  Reliability, Mission Readiness

Reliability, Mission Readiness

  Maintenance costs

Maintenance costs

  Operating costs

Operating costs

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Contamination Control Contamination Control

  Starts with system design

Starts with system design

  Involves every component

Involves every component

  Cannot be accomplished by filtration alone

Cannot be accomplished by filtration alone

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Requirements for effective Requirements for effective contamination control contamination control

  Design optimized for contamination control

Design optimized for contamination control

  Design optimized for the intended function

Design optimized for the intended function

  Clean components before assembly

Clean components before assembly

  Clean assembled system (roll off cleanliness)

Clean assembled system (roll off cleanliness)

  Filtration optimized for dynamic operations

Filtration optimized for dynamic operations

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Characteristics of Modern Characteristics of Modern Hydraulic Systems Hydraulic Systems

  Small

Small reservoir volume (relative to flow rate)

reservoir volume (relative to flow rate)

  Most

Most of the fluid in the system is in constant

• f the fluid in the system is in constant

recirculation recirculation

  Pump

Pump output adjusts to system demand

• utput adjusts to system demand

  Duty

Duty cycle includes random flow changes;

cycle includes random flow changes; low, and zero flow. low, and zero flow.

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  Contamination level in the fluid is not

Contamination level in the fluid is not homogenous and varies throughout the duty homogenous and varies throughout the duty cycle cycle

  In normal operations, volumes of cleaner fluid

In normal operations, volumes of cleaner fluid are intermingled by volumes of more are intermingled by volumes of more contaminated fluid contaminated fluid

  All components in a re-circulating system will

All components in a re-circulating system will be exposed to contaminants released by any be exposed to contaminants released by any

• f the components, including the filter
• f the components, including the filter

Characteristics of Modern Characteristics of Modern Hydraulic Systems Hydraulic Systems

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Contamination in a Hydraulic Contamination in a Hydraulic System System

  Average contamination levels determine wear

Average contamination levels determine wear rates rates

  Maximum contamination levels cause operational

Maximum contamination levels cause operational failures failures

  Operational failure occurs when the contamination

Operational failure occurs when the contamination level exceeds the tolerance threshold of a critical level exceeds the tolerance threshold of a critical component component

  Sensitive components are at risk when they are

Sensitive components are at risk when they are exposed even to short periods of increased exposed even to short periods of increased contamination contamination

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Sensitive components will fail when their contaminant Sensitive components will fail when their contaminant tolerance level is exceeded, regardless of the length tolerance level is exceeded, regardless of the length

• f time they operate in a clean environment
• f time they operate in a clean environment

Contaminant Sensitivity Contaminant Sensitivity

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What do filters do? What do filters do?

  Capture

Capture some some of the built in,

• f the built in, ingressed

ingressed, or wear , or wear generated contaminants generated contaminants

  Do not retain

Do not retain all all of the captured contaminants

• f the captured contaminants

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Total Filter Performance Total Filter Performance and Fluid Cleanliness and Fluid Cleanliness

Contamination level in the fluid downstream Contamination level in the fluid downstream

• f the filter is a function of:
• f the filter is a function of:

  Capturing Efficiency Capturing Efficiency   Retention Efficiency Retention Efficiency

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Filters must be rated for their ability to Filters must be rated for their ability to control contamination, control contamination, and maintain it and maintain it below the specified maximum below the specified maximum during the during the entire duty cycle entire duty cycle Rating Filters

Rating Filters

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The Multipass Test The Multipass Test

  Re-circulating system (Closed Loop) Re-circulating system (Closed Loop)   All contaminant passing through the filter is returned All contaminant passing through the filter is returned to the filter to the filter   Full flow through the filter Full flow through the filter   Constant challenge (contaminant injection constant Constant challenge (contaminant injection constant relative to the flow) relative to the flow)   All contaminant injected is accounted for either in the All contaminant injected is accounted for either in the filter, or suspended in the fluid filter, or suspended in the fluid SSI SSI

Filter Tests and Ratings Filter Tests and Ratings

  The ISO 16889, it

The ISO 16889, it’ ’s predecessor ISO 4572, ISO DIS s predecessor ISO 4572, ISO DIS 23369, MIL PRF 8815, and other filter test 23369, MIL PRF 8815, and other filter test specifications in common use; are specifications in common use; are filter ratings filter ratings

  They are intended to determine the

They are intended to determine the relative ranking of relative ranking of filters filters under arbitrary laboratory conditions under arbitrary laboratory conditions

  These specifications do not relate filter performance

These specifications do not relate filter performance to fluid contamination levels in a dynamic operating to fluid contamination levels in a dynamic operating system system

  MIL PRF 8815 doesn

MIL PRF 8815 doesn’ ’t yield any useful information t yield any useful information relating to the ability of the filter to control relating to the ability of the filter to control contamination in a dynamic operating system contamination in a dynamic operating system SSI SSI

Dynamic Filter Efficiency Dynamic Filter Efficiency

(DFE) (DFE)

A method of relating the total performance A method of relating the total performance

• f the filter to the contamination level in the
• f the filter to the contamination level in the

fluid under dynamic operations: fluid under dynamic operations:

  Capturing Efficiency

Capturing Efficiency

  Retention Efficiency

Retention Efficiency

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What is DFE? What is DFE?

  Variations in contamination levels are inherent

Variations in contamination levels are inherent to dynamic operating conditions prevailing to dynamic operating conditions prevailing during the duty cycle during the duty cycle

  Variations in contamination can exceed safe

Variations in contamination can exceed safe levels during normal operations levels during normal operations

  DFE is the test used to determine the maximum

DFE is the test used to determine the maximum contamination level a filter can control in a contamination level a filter can control in a dynamic operating system dynamic operating system

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DFE Rating DFE Rating

The DFE Rating

• f

a filter defines its The DFE Rating

• f

a filter defines its performance in terms of the fluid cleanliness it performance in terms of the fluid cleanliness it can maintain under dynamic operating conditions can maintain under dynamic operating conditions

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10 20 30 40 50 60 70 80 90 100 00:01:33 00:05:48 00:10:03 00:14:21 00:18:39 00:22:55 00:27:13 00:31:31 00:35:47 00:40:03 00:44:21 00:48:39 50 100 150 200 250 4µ 5µ 6µ 10µ 14µ 20µ 25µ dP

• Poly. (4µ)
• Poly. (5µ)

Example, filtration Efficiency

Scientific Services, Inc Scientific Services, Inc

Charlie Juhasz Charlie Juhasz Technical Director Technical Director Scientific Services Inc. Scientific Services Inc. SSI SSI

Economic Considerations Economic Considerations

• Cost of operating with contamination

Cost of operating with contamination in the system in the system

• Filter Effectiveness

Filter Effectiveness

• Economic Benefits

Economic Benefits

4.5% 10.5% 60.5% 18.1% 6.5% 0% 10% 20% 30% 40% 50% 60% 70% 1 2 3 4 5+ % Samples

USN, USMC & USCG ground aircraft ≥ class 5. USN, USMC & USCG ground aircraft ≥ class 5. Class 3 considered max acceptable Class 3 considered max acceptable

NAVAIR Class ~ Increasing Contamination

Army Helicopter Hydraulic Fluid Samples

(FY01)

Contaminated Contaminated Hydraulic Components Hydraulic Components

CH-47D Integrated Lower Control Actuator (ILCA) Components

Electrical 5% Mechanical Operation 20% Leaking 59% Mechanical Wear 16% Failure Code

Annual Helicopter Cost Annual Helicopter Cost

26 Critical Hydraulic Parts 26 Critical Hydraulic Parts

CCSS Annual Demand & Average Overhaul Cost (FY04) CCSS Annual Demand & Average Overhaul Cost (FY04)

UH-60 1396 A/C AH-64 742 A/C CH-47 429 A/C OH-58D 382 A/C

$25.9M $3.3M $5.3 $11.2M Total = $45.7M

Per Fleet

$12,400 $8,800 $15,100 $18,500

UH-60 AH-64 CH-47 OH-58D

Per A/C

2410 Failure Codes (FY04)

Per industry data, ≈75% of failures are due to contamination.

CCSS Annual Demand & Average O/H Cost

Fiberglass Filters are Not Effective in Dynamic Environments

Increased Flow (1.5 x Nominal) Time: 40 Sec

• Flow rate changes cause trapped particles to re-entrain in fluid.
• Similar results are produced by:

– Pressure changes – Helicopter vibrations – Pump pulsation (ripple) – Fluid temperature changes

Steady Flow (1.5 x Nominal) Time: 80 Sec Steady Flow (Nominal) Time: 0 - 30 Sec Downstream

• f Filter

Upstream

• f Filter

Dynamic Test at SSI (FY01)

Mil F 8815 /7 -12 Element Mil F 8815 /7 -12 Element

MIL F 8815/3-12 Housing MIL F 8815/3-12 Housing

Efficiency & Capacity Variations depending on the cycle frequency and the method used for testing 52 76 77 30 3.57 4.03 4.88 2.57 10 20 30 40 50 60 70 80 90

0.1 Hz- DFE 0.1 Hz -ISO-Pall-unsynchronized Steady Flow Dynamic Filtration Efficiency (DFE) - 3 min High Flow-3 min Low Flow

Minimum Efficiency -% (or) Capacity -gms

• Min. Efficiency @ 5

microns Capacity -gms@ 90 psid

Tested Element- Typical Glass Media - conforming to (AN 6235-4-Pall 9020) size-Aftermarket 6 mic(c)

TEST #S: 020081/83/88/181;TEST DATE: May 2002

Filter Rating: 12 mic. Steady Flow Tests test # s/ particle mic sizes> 6 10 14 20 ln030037 93.08 99.9 99.99 99.99 ln030036 93.91 99.97 99.99 99.99 ln030034 94.04 99.93 99.99 99.99 average 93.67667 99.93333 99.99 99.99 standard deviation 0.520801 0.035119 1.3487E-06 1.3487E-06 coeff variation-% 0.6% 0.04% 0.00% 0.00% Average Filtration Efficiency -NO flow changes -steady

Repeatability within the Test Lab on an identical Element

(using the closed- loop Dynamic Filtration Efficiency Test Stand at SSI Labs)

Conclusion: The variation in efficiency from element to element is acceptable .The variation is comparable to round robin tests on elements tested with ISO 16889 -steady flow test procedure

Dynamic Flow Tests test # s/ particle mic sizes> 6 10 14 20 ln030029 84.93 93.2 99.9 99.9 ln030028 92.2 99.93 99.99 99.99 ln030030 92.15 99.89 99.99 99.99 average 89.76 97.67333 99.96 99.96 standard deviation 4.182977 3.874072 0.051961524 0.051961524 coef variation-% 4.7% 4.0% 0.1% 0.1% Lowest Filtration Efficiency after the flow change

Conclusion: The variation in efficiency from element to element is acceptable .The variation is comparable to round robin tests on elements tested with ISO 16889 -steady flow test procedure

Repeatability within the Test Lab on an identical Element

(using the closed- loop Dynamic Filtration Efficiency Test Stand at SSI Labs)

Particle Size Vs. Efficiency-Average- Steady Flow Filter Effciency test on SSI's test stand (similar to ISO 16889-except for closed loop recirculation-dirt injection)

20 40 60 80 100 120 1 10 100 Particle Sizes- Microns Efficiency -% time weighted avg. ln030037 ln030036 ln030034 COV-% on micron size at 99.5% efficiency is << 5%

Efficiency variation from Element to Element using DFE Procedure-dynamic test (Cycling Flow) on SSI's Test Stand

20 40 60 80 100 120 1 10 100 Micron Sizes-microns Efficiency -lowest- after the flow change from low to high LN030028 LN030030 LN030029 COV-% on micron size at 99.5% efficiency is << 5%- `

Particle Counts 3 mic (c) - up and down stream of restriction at ~3 mg/liters upstream presure: 110 to 450 psi, downstream pressure 84-180 psi cyclic flow: 12 gpm to 8 gpm @ 3 min on and 3 min off

2000 4000 6000 8000 10000 12000 14000 5 10 15 20 25 30 35

test time - minutes

# of particles /ml

upcount1 dncount1 ISO max limit 3 mg/l ISO min limit 3 mg/l

Filter Performance Steady Flow Filter Performance Steady Flow

Filter Performance Changing Flow Filter Performance Changing Flow