DFE - Testing Filters Under Real-Life Conditions, Part 4 of 4

Posted by Jim Harlan on Tue, Jul. 18, 2017

Throughout the first three entries in this series we've discussed the difference in two filter element testing methods, ISO16889 and DFE. We've also illustrated how many elements fall short of their stated beta ratio under dynamic flow conditions. Today we'll wrap it up with simulated cold start tests.

DFE Multi-Pass: Cold Start Contamination Retention

Once the element has captured enough contaminant to reach approximately 90% of the terminal ΔP (dirty filter indicator setting), the main flow goes to zero and the injection system is turned off for a short dwell period. Then main flow goes to maximum element rated flow accompanied by real time particle count to measure retention efficiency of the contaminant loaded element. The dynamic duty cycle is repeated to further monitor the retention efficiency of the filter element after a restart.

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Topics: hydraulic fluid, ISO 16889, ISO Fluid Cleanliness Codes

DFE - Testing Filters Under Real-Life Conditions, Part 3 of 4

Posted by Jim Harlan on Tue, Jul. 11, 2017

Last week we covered the differences between the ISO16889 Filter Test Procedure and the DFE Filter Test Procedure. This week we illustrate the difference between elements engineered to retain particles during dynamic flow conditions and those that are engineered only to pass the ISO16889 test.

Quantifying Contaminant Capture and Retention

Figure 2 compares the performance of two identical high efficiency glass media filter elements, one tested to ISO16889 multi-pass and the other to the DFE multi-pass method. The graph expresses the actual number of particles 6μ[c] and larger counted downstream of the filter element from several data points during the tests.

Filter A2 was tested at a constant flow rate and maintained a steady efficiency throughout the test. Filter A1 was cycled between max rated flow rate and half of rated flow with a duty cycle consistent with that of a hydraulic system. The downstream counts for Filter A1 varied and were highest during changes from low flow to high flow. The peaks represent counts taken during flow change and the valleys represent counts taken after each flow change. The alternating high peaks represent counts taken during changes from low flow to high flow. As the amount of contaminant captured by Filter A1 increased, the downstream counts increased most dramatically during the flow changes from low to high. Filter element A1, not properly designed to retain previously captured contaminant during dynamic system conditions, can become a dangerous source of contamination as it captures and then releases concentrated clouds of contaminated fluid.

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Topics: hydraulic fluid, ISO 16889, ISO Fluid Cleanliness Codes

DFE - Testing Filters Under Real-Life Conditions, Part 2 of 4

Posted by Jim Harlan on Tue, Jun. 27, 2017

Last week we briefly discussed how filter elements are rated by manufacturers. This week we're discussing the industry standard ISO16889 multi-pass test and Hy-Pro's standard, the DFE test.

Current Filter Performance Testing Methods

To understand the need for DFE it is important to understand how filters are currently tested and validated. Manufacturers use the industry standard ISO16889 multi-pass test to rate filter efficiency and dirt holding capacity of filter elements under ideal lab conditions.

Figure 1 depicts the test circuit where hydraulic fluid is circulated at a constant flow rate in a closed loop system with and on-line particle counters before and after the test filter. Contaminated fluid is added to the system at a constant rate. Small amounts of fluid are removed before and after the filter for particle counting to calculate the filter efficiency (capture). The capture efficiency is expressed as the Filtration Ratio (Beta) which is the relationship between the number of particles greater than and equal to a specified size (Xμ[c]) counted before and after the filter. In real world terms this test is the equivalent of testing a filter in an off-line kidney loop rather than replicating an actual hydraulic or lube system. It’s basically a filter cart test.

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Topics: hydraulic fluid, ISO 16889, ISO Fluid Cleanliness Codes

DFE - Testing Filters Under Real-Life Conditions, Part 1 of 4

Posted by Jim Harlan on Tue, Jun. 20, 2017

The Dynamic Filtration Efficiency (DFE) Test is Hy-Pro's standard for testing filter elements. Throughout this 4 part series we'll discuss what it is, why it matters and why elements engineered with this test in mind outperform others in real-life applications.

First, let's start with the basics...

Why are filters used? How are they rated?

All hydraulic and lube systems have a critical contamination tolerance level that is often defined by, but not limited to, the most sensitive system component such as servo valves or high speed journal bearings. Defining the ISO fluid cleanliness code upper limit is a function of component sensitivity, safety, system criticality and ultimately getting the most out of hydraulic and lube assets.

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Topics: hydraulic fluid, ISO 16889, ISO Fluid Cleanliness Codes

Hydraulic Pump Reliability

Posted by Jim Harlan on Tue, Feb. 21, 2017

The Problem

Pumps are the heart of hydraulic systems. When the pump fails, the entire system is down until the pump is operational again. This poses a serious threat to any operation relying on hydraulic systems for productivity. Recently, a hydraulic valve manufacturer was losing 25 pumps a year on their centralized hydraulic system at a cost of $2,440 each. That’s only the pump cost, when you account for maintenance resources, lost oil and lost production each failure costs ~$25,320.

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Topics: hydraulic fluid, contamination, fluid cleanliness, dirt, iso cleanliness codes, ISO 4406, filtration, Fluid Analysis

Cleanliness Requirements for Fluid Transfer

Posted by Jim Harlan on Tue, Feb. 07, 2017

The Problem

Today’s oil suppliers are often required to provide fluid at or below a specified ISO Cleanliness Code. One such supplier was experiencing short filter element life (15 days) on the system (7 element multi-round housing) used to achieve the required ISO Cleanliness Code of 18/16/13 in a single pass as 15W-40 oil is transferred from their bulk storage tanks to tanker trucks for delivery.

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Topics: hydraulic fluid, contamination, fluid cleanliness, dirt, iso cleanliness codes, ISO 4406, filtration, Fluid Analysis

Gearbox Lube Oil - Aluminum Refinery

Posted by Jim Harlan on Wed, Dec. 14, 2016

The Application

An Australian aluminum refinery was consistently performing premature gearbox lube oil changes on 7 base drive units due to oil and particulate contamination. With an average operating ISO code of 20/18/16 and average water levels of 4742ppm, the 360 liters / 90 gallons of ISO VG320 gear oil was being changed far too often. Cost per gearbox oil change (excluding crane, lost production, labor) is $17,962.60 which adds up to $125,738.20 for all 7 units.

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Topics: hydraulic fluid, contamination, fluid cleanliness, dirt, hydraulic filters, iso cleanliness codes, ISO 4406, fluid samples, filtration, Fluid Analysis

Hydraulic Valve Performance Test Stands & Clean Oil

Posted by Jim Harlan on Tue, Nov. 29, 2016

The Application

A hydraulic valve manufacturer required pristine fluid (< 14/12/9) to test flow across an 80 micron orifice on their test stand. Gross amounts of contamination in the fluid would skew the test results, invalidating any data collected. The system held 100 l (26.4 gal) of ISO VG 32 fluid with a flow rate of 25 lpm (6.6 gpm).

Through observing the manufacturer’s sampling practices, discussing fluid handling best practices and interpreting their lab reports; 3 independent problems were identified:

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Topics: hydraulic fluid, contamination, fluid cleanliness, dirt, hydraulic filters, iso cleanliness codes, ISO 4406, fluid samples, filtration, Fluid Analysis

Video: Your Lab Reports Are Probably Wrong - Here's How To Save Them

Posted by Scott Howard on Tue, Aug. 16, 2016
When looking at a lab report it is assumed the information on the report is accurate. A certified lab will not usually make an error in the report, but if so it is obvious and easily fixed. Ever hear the saying "By the time the lab gets the report the error has already been made?" For the most part this is true. Where people are led off course is believing the particle count on the lab report is the gospel. This is natural, but unfortunately not always the case with a bottle sample unless you already employ the techniques listed in the video below.
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Topics: hydraulic fluid, fluid cleanliness, dirt, hydraulic filters, ISO 16889, iso cleanliness codes, ISO Fluid Cleanliness Codes, diesel, ISO 4406, fluid samples, filtration

Vacuum Dehydrator Called On To Save Fishing Season

Posted by Jim Harlan on Fri, Apr. 15, 2016

One of our V1S vacuum dehydrators was recently put to the test in a marine application with hydraulic oil contaminated by more than 2500 ppm of water. Sink or swim? Find out below.

The Problem- When a seal fails on your net hauler hydraulics out at sea, the costs and lost profits stack up quickly. In this instance, salt water began entering the hydraulic fluid on a 245 ft (75 m) purse seiner through a seal leak, rendering the net hauler out of commission. Faced with frequent fluid exchanges at a cost of $9300 plus disposal, or worse, substantially larger lost profits from downtime for replacement of the seal, the vessel owner was in desperate need for a solution to allow him to continue operating without fear of malfunctioning equipment.

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Topics: hydraulic fluid, contamination, water in oil, fluid cleanliness, water, dirt, Water Contamination, hydraulic filters, maintenance, fluid samples