Multi-Channel Leak Testing Done Right - Uson

Let’s face it everybody wants to get more done with less. Whether we are talking staffing, robots, AI or automated assembly lines – the more you can do faster, the better. The same, of course goes for leak testing. As it’s our business, we know that for some (many) manufacturers, leak testing is a necessary but not so popular activity. It often happens at the end of the manufacturing process and can become a bottleneck.

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Factory throughput is a major challenge facing production engineers and woe betide the quality control team that makes that challenge even harder. The leak testing bottleneck can be improved by adding more testers, but a a price or by finding a way to test several parts or assemblies at the same time. Multiple parts are often connected to a common test port using a manifold in the attempt to increase testing throughput.

The manifold approach to leak testing has two serious drawbacks. First, the manifold and the parts themselves create a large volume. The increased volume reduces sensitivity causing longer test times, which is precisely what multiple testing was trying to solve. Given what I just wrote a few sentences ago that doesn’t seem the smart solution does it? But wait, there’s more….

Because the parts are connected to one common air source, the tester has no way to identify which parts failed. A failure in any part demands a second test. This re-testing takes even more time.

Sprint mD Multi-Channel Testing Capabilities

Uson has several leak testers that can deliver multi-channel concurrent testing, Optima vT, Vector and Sprint mD. Let’s look at the Sprint mD as it is the most economical and effectively serves the medical device market where high volume production of small parts and devices is common place. Sprint mDcan be configured as a four-channel pressure decay tester with four independent sensors and test circuits contained in one compact machine. Four parts are independently tested at the same time without a manifold.

Each part tested has its own bar graph and status window on Sprint’s large liquid crystal display.  The operator knows exactly which parts failed. No re-testing. Because the four test circuits are independent, the volume remains small and the test is much faster than a manifold-type test.

Using the Sprint mD is similar to running four testers at the same time. But it’s better because Sprint costs so much less than four machines.

How it Works

The Sprint mD tester works like this:

• Product [P] is attached to the four test ports either manually or by automated machinery. (Figure 1)
• The test is initiated by pressing Sprint mD’s start button or by remote input.
• Sprint mD pressurizes the four parts with the fill valve [V1] then traps air in each separate test circuit between the product and the valve.
• Trapped air pressure in each of the four test circuits is measured by an individual pressure sensor [S].
• If any of the four parts fail, Sprint’s large gauge dial turns red and a signal is sent to the I/O port.  Sprint mD’s high definition display shows exactly which parts pass and which parts fail.(Figure 2)
• The Sprint mD display shows all four channels at the same time.Each channel (test port) has its own bar graph and status indicator.
• The large color display is easy to read under varying lighting conditions showing the status during each test, the display indicates fill, stabilization, test and dump during the respective cycle period.
• In an automated operation, the pass fail information is sent to SprintmD’s I/O port on the back of the machine.

Applications

This multi-channel tester is an extremely flexible machine with the ability leak test a broad range of products. From small to large, rigid to flexible, Sprint mD is perfectly suited to the challenge of accurate testing that is both fast and affordable. The Sprint mD can be used to test either multiple products or products that have multiple parts.

Goto saimr to know more.

Other Sprint Models

Although you can use the four-channel machine to test fewer channels, if you don’t need all four channels, SprintmD is also available in two and three channel configurations.

Mass Flow

A Sprint mD’s four channel Sequential tester can test four parts using mass flow in series. One mass flow transducer tests four parts one after the other for leakage, blockage, or for correct flow rate.

Features

• Extremely fast
• 16 Programmable Inputs/Outputs
• Local authentication, audit logs, test setup, statistics, real-time data, self-test diagnostics
• Large 8.5” color touch screen LCD with a rich dashboard-style user interface
• Tests large or small volume parts
• Can use as a 1-4channel tester
• Perfect for bench or automation
• Small footprint (10 x 12 Inches)
• 24-bit ADC for high-resolution pressure measurement
• Easy to program and calibrate
• Many available options!

Contact us for more information about the Sprint mD’s Multi-Channel leak testing capabilities or reach out to your local Uson Representative.

-article by Sam Myers, Retrotec

Reducing air leaks in duct systems plays an essential role to ensure efficient HVAC system operation. This keeps operating costs down and occupants comfortable. The duct tester equipment used to test for air leaks in duct work is made up of a calibrated fan, high precision manometer, tubing to connect the manometer to the fan, and flexible duct to connect the duct tester to the HVAC system. The technology applied to commercial duct testers has greatly improved over the past decade. What used to be a large blower bolted to a wheeled hand truck can now be easily carried by one worker in a case with a shoulder strap; all without sacrificing power. However, even with some of the most powerful duct testers out there, more fan power is needed for extremely large HVAC cabinets to reach a desired test pressure. Some of these cabinets can be the size of a mobile home, which is far too large for a single duct tester to handle. Some testers are making their own duct testers with a larger blower, though accuracy is greatly reduced and uncertainty is increased when this route is taken. The test pressure for commercial duct leakage tests varies from project to project. This pressure is typically specified by the mechanical engineer who designed the system. Test pressures typically range from 3 to 10 in. W.C. In order to pass the test, an air handler or air handler and trunk must be at or below a certain flow (CFM) at a given pressure (in. W.C.).

Currently, there is only one accurate method for testing large HVAC cabinets where more than one duct tester is needed. It is similar to the process that is used to test commercial building enclosures with multiple blower door fans. This requires connecting multiple fans and digital manometers together and using software to ensure all of the fans are running at the same rate. The software then aggregates the readings together from each manometer to provide a total leakage amount once the desired pressure is reached.  

In the diagram below, you can see three duct testers connected to one large commercial air handler cabinet. Each duct tester has it’s own digital manometer that reads fan pressure, duct/cabinet pressure, and ambient pressure. This is done with color coded tubing represented by the curved lines that begin at the top of the manometer and plug into the fan (green and yellow) and air handler (blue). The lines that turn at a 90 degree angle represent Cat 5 cables. Notice that the manometer on top connects to the fan with a yellow Cat 5 cable, but none of the others do. That’s because this first manometer on the line is the dominant manometer. It plugs into the fan, then that fan is plugged into the next fan. This repeats until all of the fans are daisy chained together with Cat 5 cables. This setup allows all of the fans to run at the same speed at the same time so they work together to reach a desired pressure. This also prevents the fans from fighting each other. Since the control signal is coming from one dominate manometer, all of the fans are following orders from the same source. The rest of the manometers are still needed to read fan pressure from the fans they are connected to and report back to the software. Each of these manometers uses a Cat 5 cable that plugs into the bottom of the manometer with the other end plugged into a router. The router is then plugged into the laptop which allows the tester to use FanTestic software to control all aspects of the test from one location. The software also ensures that all of the fans and manometers are responding as they should. The tester can keep an eye on each of the manometers at once and run the entire system at the push of a button to complete the test and generate a report. Below is an example of the test analysis table that is included in the test report generated by the software. These test reports also comply with the SMACNA HVAC Air Duct Leakage Test Manual.

Another benefit to learning the multi-fan process for testing large HVAC systems is that it can open the door to additional opportunities. Once you familiarize yourself with the software and setting up the fans and manometers, you can then perform air tightness tests on large building enclosures. The same software is used and you set up everything in a similar fashion. The only difference is you swap out the duct tester fans with blower door fans. Of course there is also the building preparation work that is involved, but the testing process is very similar. Learning the equipment and software is half the battle.

For more multi channel air leakage testerinformation, please contact us. We will provide professional answers.