InterTech Solution For Testing Carbon Canisters

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Single Station Leak Test Stand for Testing Carbon Canisters

idc single station leak test stand for carbon canisters

idc single station leak test stand for carbon canisters

The InterTech M1075 Mass Flow Leak Detector with early pass controls the leak test cycle.

  • The downstream test method allows for fast test times independent of temperature and carbon out gassing effects.
  • The machine is designed ergonomically for ease of operator use.
  • Canister configurations are tested to an 8.0 sccm limit at 20 kPa (2.9 psig), in approximately 10 seconds.
  • With this leak test solution from InterTech, Gage R&R meets stringent quality requirements of less than 20%.
  • Proven InterTech leak test instrumentation and fixture designs ensure production efficiencies.

 

Follow the InterTech India blog for more solutions on leak and functional testing.

InterTech has its sales and demonstration offices in Chennai, India. For sales enquiries, you may contact us at;

Mobile: +91 994 032 0718

eMail: ajay@intertechdevelopment.com

Land phone: +91 44 4211 2525

 

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InterTech M1075 – for unsurpassed leak testing speed and accuracy

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An InterTech Design Report

Our diesel engine mass flow technology shortens test cycle time by finding leaks faster to enhance manufacturing efficiency and process – significantly. Download the full report in a PDF format at:DR129_R1

The Challenge

Develop a production line solution to detect and repair leaks prior to hot testing. Eliminate the possibility of leak-associated defects getting through the system. Deliver accurate results in seconds, while not wasting time and money on hot test repeats.

InterTech M1075 – for unsurpassed leak testing speed and accuracy - using Mass Flow, Pressure Decay & Differential Pressure Testing

InterTech M1075 – for unsurpassed leak testing speed and accuracy

The InterTech Solution

InterTech M1075 dry air tests both the water side and the oil side of an engine block at the same time, up to twice as fast as other available options.

The water side includes engine block passages, water pump, heater housing, thermostat housing, associated hoses and the coolant half of the lube-oil cooler, creating a cavity of about 12 liters. The oil side includes engine block passages plus, front and rear gear fly wall housings, crankshaft seals, oil pan, intake manifold and the oil half of the lube-oil cooler.

This creates a cavity of up to 180 liters depending on engine model. The InterTech testing system avoids problems of pressure fluctuation in the supply line by using isolated air reservoirs. Because it is independent of plant air supply, it provides a direct and stable measurement of leakage.

The InterTech system simultaneously pressurizes both cavities and the reservoirs: the oil cavity to 2.5 psi with a reject limit range of .2 lpm to1.4 lpm (user selectable); and the water cavity to 10 psi with a reject limit of 25 sccm.

Any leakage causes the leaking cavity to lose pressure and the InterTech mass flow transducer reads the flow rate.

 

For a customised quote for your leak testing problems, contact our Indian office in Chennai at 044 – 4211 2525 / +91 994 032 0718 / +91 98409 14544

You may also email our Sales Reps in India at ajay@intertechdevelopment.com / ram@intertechdevelopment.com

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Leak testing 101 – Part 1

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Not too long ago, when you wanted a product to be leak-proof, you simply put it under water, made sure it didn’t bubble, and thereby concluded there were no leaks. Such “bubble testing” takes time and depends on the operator’s ability, making it totally inappropriate for the modern production environment. Also, it doesn’t generate the quantitative measurements that are the lifeblood of quality assurance engineering.

Dry-air leak testing methods—some of which can detect leaks as small as 0.01 standard cubic centimeters per minute (sccm)—are the methods most commonly used today by a wide range of industries—from medical devices, to automotive, to appliances, and aerospace, among others. These dry air methods enable quality managers to define leaks quantitatively.

“No leaks allowed” standards are concepts of the past. There are a variety of dry air leak test methods and best-practice techniques for each type of method, which will enable compliance to ISO 9001 and comparable quality management standards to be achieved. Generally speaking, these dry air leak test methods include;

  • Pressure testing
  • Differential pressure-decay testing
  • Mass flow leak testing

In addition, tracer gas testing and especially helium mass spectrometer leak testing, are used in more demanding applications where leaks as small as 10-5 standard cubic centimeters per second (sccs) must be detected in a production environment. If one truly understands leak testing application requirements and best practice techniques for these various leak test methods, the selection of which type of testing to perform is a rather straightforward matter.

The first step in designing a leak testing solution is to correctly define what the leak limits are. Leak testing applications laboratories begin with an engineering analyses of a specific application to determine and quantify how much a product or component can leak. Often, correlation studies are performed to verify if it is possible to use dry-air test methods instead of hydraulic fluids. Sample parts are tested as part of an initial engineering analysis. These determine the production requirements and leak standards to be achieved so that quality engineering of test solutions can begin. The first step in this process is to select the leak testing method that is the best match to application requirements.

In this “Leak Testing 101” series we will discuss the various dry air leak testing methods and the issues and techniques that affect testing costs and gauge repeatability and reproducibility (GR&R).

First, let’s take a look at the pros and cons of pressure-decay testing.

The big plus of pressure-decay testing—or at least the thought behind it—is that the leak detectors for pressure-decay leak testing have the lowest upfront cost. It is probably for this reason that the method is still in use, although in many applications the real costs of pressure-decay testing are actually much higher than many realize.

In the pressure-decay method for leak testing (see figure 1), a part is pressurized, the test circuit is isolated, and the pressure drop associated with a leak is measured. A transducer reads the pressure change. Calculations then convert these time/pressure readings into a measure of leakage rate. The higher costs of pressure-decay testing stem from the difficulties inherent in the test methodology. Pressure-decay leak testing is relatively difficult because measurements are highly vulnerable to changes in testing conditions such as drafts or temperature and there are often difficulties in determining the volume of test parts and test circuits, which must be known in order to calculate results.

Pressure Decay Method of Dry Air Leak Testing

Pressure Decay Method

Also, pressure-decay leak testing requires two measurements of pressure with sufficient elapsed time between measurements. When speed of testing is an issue, this built-in delay makes the pressure-decay method less desirable. More important, the two measurements and the time lapse significantly increase the potential for measurement error. The amount of time you need to wait between measurements varies. Sometimes, long intervals between measurements can make for extreme accuracy, but these long wait times are typically not practical. The larger the part volume, the longer it takes to measure the pressure drop. Moreover, very large flows are also impractical with pressure decay, because when pressure drops very fast, it will probably not be measured accurately.

Thus, although pressure-decay leak testing instruments have a relatively low upfront cost, the extra time it takes to perform testing (if the results are reliable enough for the given application) is another expense that needs to be factored in to overall cost. It can still be the best leak test method for a specific application, but the trend lines are in the other direction. Most applications now require tighter GR&R even for very low leak rates, often with large volume parts, and with a desire to keep test cycle times to the bare minimum to cut overall testing costs.When you factor all these considerations in, it often leads one to use other leak test methods instead.

In the upcoming issues of this “Leak Testing 101” series I will discuss differential pressure-decay testing, mass-flow leak testing, temperature compensation issues, and many other topics. By the conclusion of Leak Testing 101, my goal is to bring all quality managers up to speed on the real factors that affect leak testing cycle times, costs, and reproducibility.

If you would like your specific questions on best practices for leak testing (and other testing topics) to be discussed in future articles, please leave your comments and suggestions in the Comments area below.

ABOUT THE AUTHOR

Jacques Hoffmann’s picture

Jacques Hoffmann

Jacques Hoffmann is founder and president of InterTech Development Co., a world leader in test-centric assembly specializing in automated leak and functional testing with mass flow, hydraulic, helium, or pressure decay technology (ISO-17025 accredited). InterTech Development Co.-engineered solutions are used by hundreds of quality management, product design teams, and manufacturers worldwide and the company’s worldwide support organization maintains offices in North America, Asia, and Europe.

Note:  The above article has been reproduced from an article written by the author for Quality Digest

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Learn more about turnkey hydraulic testing systems

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When your production focus is vehicular manufacturing—automotive, diesel or off road—there is no shortage of challenges when it comes to hydraulic testing.

Quite often one is dealing with a high production rate requirement usually in excess of 150 parts per hour. Conversely, individual part test time must be completed in a matter of seconds.

Blink-of-an-eye production rates ensure that traceability is a fundamental necessity and, combined with a programmable marking system, remain a manufacturer’s most important quality control ally. But ensuring that you have such systems in place is another challenge.

Overlaying these issues is the reality that today you are likely manufacturing for global markets. So for example, while durability and reliability are always issues, they are even more so when a given part you are testing in-line has to be as reliable in Quebec as it is in Qatar.

Clearly, manufacturers who rely on an automated, up to date turnkey system for hydraulic testing are sleeping better this evening. So what do these systems look like? And what are the key features and benefits justifying the investment you will make in a turnkey system? Let’s consider a few applications that explore these questions.

The first functional test stand automatically tests, marks and sorts hydraulic solenoid valves. Of course, the hallmark of a forward thinking turnkey system is flexibility, so this modular design accommodates future product configuration changes.

In operation, the solenoid valves are automatically transferred from the test station to the marking station where programmable marking automatically identifies each part for traceability.

Then on to the unload station for classification based on test results; in this case there are three accept bins and one reject bin. Rejects are automatically unloaded into a separate bin with discharge verification to eliminate the possibility of shipping defective product. Test data is stored by serial number to document the supplier’s quality assurance program for a series of Six Sigma moments a QC manager would have to admire.

For maintainability, ready access to all machine components is provided. And today’s turnkey system must be user friendly. This one incorporates a Windows test program to allow the authorized engineer to easily change all test parameters (accept/reject levels, duty cycle, duty cycle increments) and interface with LAN data collection devices.

A turnkey system such as this one gives a manufacturer complete control and management of a hydraulic test station.

Relief Valve Hydraulic Functional Test Stand

This turnkey system is built for speed—automatically testing, marking and sorting a family of valves at 152 pph. Temperature control of the test fluid was critical for accurate testing, and to meet automotive industry requirements for test R&R. So a closed loop system was designed to maintain consistent fixture temperature (100 F ± 3 F).

The instrumentation performs eight tests:

  • unseat (1,600 psig) and reseat (1,400 psig) at minimum flow
  • pressure at maximum flow
  • low pressure integrity test at 20 psig
  • high pressure leakage at 2,000 psig max
  • low pressure at 100 psig max
  • internal seat leakage of 900 psig
  • O ring check at 6 psig (air test)

What goes into this high-speed system? At its heart is modular instrumentation for flexibility and ease of maintenance. Test parameters are programmed to meet industry requirements, automatically selected, and sequentially performed. Dial transfer of parts, automated handling and sequencing of tests minimizes cycle time.

Through a fail-safe protocol, only accepted parts are marked, while automatic unloading and sorting prevents rejects from continuing down the production line. Reliability, which is always an issue, is ensured by repeatable positioning, a barrel cam indexer and interlocked motions. As in the prior example, tests may be easily modified through Ethernet connectivity to meet changing customer conditions and requirements.

Safety is always a concern when fluids are in the mix. So the stand is designed to contain oil spillage. Redundant monitoring systems are part of the design as well, shutting the machine down in case of heater failure or excessive pressure loss.

Finally this hydraulic test stand and turnkey system incorporates SPC capabilities. Test results and stats are displayed on a monitor in real time and sorted on disk in spreadsheet compatible format for analysis.

Testing Design Requirements

If design requirements for a hydraulic test are unclear, incomplete or somehow inadequate, trouble brews. What do clear and well thought out design requirements look like? Consider this example for a high pressure valve performance test.

Safety first is job one in a test where extremely high pressure is demanded to accurately measure incremental flow force. So the enclosure is designed and interlocked to ensure operator safety with a part under test at 40,000 psi.

All hydraulic lines from the pump to the fixture are contained in a separate housing to protect against ruptures. A liquid air over oil intensifier is used to bring the 0.5 liter rail volume up to test pressure.

A test stand should be designed with ease of operation in the forefront. So the intensifier drive air regulator is brought to the front of the machine for easier operator adjustment. A pressure relief valve is provided on the drive air regulator to ensure the maximum hydraulic pressure is not exceeded, and a small hydraulic pump is required to replenish the rail volume in between tests. A small air to oil cooler is incorporated to keep hydraulic fluid temperature at factory ambient temperature 72 to 104 F.

Finally, the fixture must work under extremely high pressure and measure flow force on valve stem lifts in increments of 0.005 millimeters. In this particular scenario, it consists of the following steps:

Implement a Piezo-electric load cell to reduce the compressive distance to 1 micron/1.05kN.

  • Accurately measures the fixture and valve stem compression and provide 10 valve lift stops in 5 micron increments.
  • Position the valve preload spring above the solenoid so that it will not influence the test system.
  • Program the data acquisition computer for the Piezo electric load cell.
  • Provide data collection points for all sensors with adjustable target time and averaging width.

In the final analysis, hydraulic testing is always challenging. But with a well thought out plan for a turnkey system, thorough preparation, clear design and testing requirements, you can reach the high product quality standards that your company aspires to achieve.

Full article details – click here IDC-Quality NDT-Article-2012 Turnkey hydraulic testing systems

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