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Thanks for the feedback! Glad it has been helpful. That is the mission!

Steven! That often results from the part being warm and the air pressurizing the part heating up. The transducer is seeing negative pressure during the test. If there is a large surface area the part could be retracting after pressurization reducing the available space and increasing the pressure in the test part. The transducer (should) zero at the start of every test. If there is pressure in the part at the beginning of the test the zero will be elevated and during the stabilization the pressure could go below the zero point. In this case make sure the part is vented or has no pressure prior to starting the test. Bad transducer calibration is another option. Using the self-test cap on a CTS unit or capping off any other type of tester should allow you to test it out. Good luck!

We can configure the CTS Sentinel I28 Leak Test Instrument with a Mass Flow Sensor for upstream measurements. We will be glad to discuss in more detail. Send your contact information to sales@capexsales.com

Hi Joe - Sure thing! adobe.ly/3souCxa

The results of your trial are as expected. Remember that with pressure decay or differential pressure decay, we are measuring pressure change. Any outside influences that effect a pressure change in the part will alter the results. Heat expands the air in the part, therefore increasing the pressure or making it appear not be leaking. Cooling contracts the air in the part, therefore decreasing the pressure in the part. Good work and thanks for sharing your study. Russ

@@russsorrells-BOSThanks for reply. For differential pressure decay method (comparing master and work side)it is obvious increasing the temperature in work side shows negative reading as pressure also increases in that side which push diaphragm towards master side. As you mentioned cooling contracts the pressure , we decreased the temperature in work side only ,reading need to show in positive but it is showing negative,why?

In my experience, positive pressure leak testing is more sensitive and repeatable than vacuum decay. This is not always the case but I am only basing my answer off of my experience. How I have tested this in the past was with a leak standard that flowed 3 sccm @ 5 psi. I tested with the leak standard at positive pressure (5 psig) and negative pressure (5 psiv). The positive pressure was more accurate than the negative pressure. Please keep in mind this was an unscientific experiment and only my findings on the specific application. Both testing methods work well and are effective at identifying leaks. The decision to use one versus the other often has to do with the part sealing requirements. If the part has a large opening the vacuum helps to seal the part versus the positive pressure pushing against the sealing surface. Also, parts that are hermetically sealed are often tested in vacuum chambers looking for a pressure rise in the chamber indicating a leak from the part. Hope this is helpful!

@@russsorrells-BOS Thank you for your reply. I have query. The leakage (pressure drop) from the components will remain the same or change if we maintain same temperature but varying atmospheric pressure means i am checking the components in different country with same temperature. Will the leakage will differ if we perform leak testing process like once by+50kpa and performing under same condition in vacuum -50Kpa? Your reply was in relative to flow i am talking about the pressure drop.Hope you got this.

Mus - Mass flow might be the most appropriate technology for testing a laryngeal tube depending on what you are attempting to detect. Do you want to verify the volumetric flow through the tube or attempting to evaluate for a leak? For volumetric flow, you might consider using low-pressure and a high-flow flow meter. It is important that the tubing from the flow meter that seals on the part is larger in diameter than the part you are testing to avoid flow restrictions. You would need to establish a reject limit. The other portion of the Laryngeal tube is the bladder. The bladder will be more challenging to test because it blows up like a balloon. We would recommend an inside out test for this type of test. You would pressurize the bladder inside of a restrictive chamber and measure pressure rise in the chamber. These are the methods I would recommend based on my limited knowledge of laryngeal tubes. Good luck and I hope this is helpful!

@@russsorrells-BOS it's reply helpful sir! Thank you for answering 😊

Hello Luis! The goal with a master part is to simulate the production parts. For example, if your part is a one liter plastic bottle, you will want to use a bottle consistent with the bottle you will be testing versus a stainless steel part that has a one liter volume. For calibration you will want to use your seals, parts with similar material and configuration. Keys to calibration = simulating thermal effects, production part seals, part expansion (plastic parts in particular), and volume changes. We want to take into account all variables during calibration. Doing so will help ensure we have a more repeatable and reliable test. Hope that helps! Feel free to ask questions!

JP TV, I don't have direct experience with the ATEQ testers. The most common technology utilized by ATEQ is differential test technology. Choosing the appropriate test technology is driven by a number of different factors. CTS offers differential pressure decay, pressure decay, and mass flow technologies. Have an awesome day and sorry for the delayed response!

Heard ATEQ are superior to CTS because of how the units are mastered.

Sup Mike! Sorry for the delay. Setting your worst negative leakers aside can definitely be a strategy for ensuring that you are utilizing the ideal part as the master. The "Ideal" master part is a part that represents the parts that will be tested on the equipment but is leak free. I encourage customers that are calibrating their equipment for the first time to select any part to calibrate the equipment with and then test at least 30 other parts (documenting the leak rate of each part). After processing all 30 parts they should select the most negative part as the master part and recalibrate the equipment with that part. Hope that is helpful. Thanks for the question!