Case Studies:

Vacuum Chamber Leak Test of Automotive Reflectors
Pressure Decay Leak Testing of Brake Caliper Assemblies
Leak and Backpressure Occlusion Test of Automotive Part with Check Valve
Vacuum Decay Leak Testing for Brake Housings
Testing Radiator Tubes for Leaks
Leak Testing Large Capacity Tanks

Vacuum Chamber Leak Test of Automotive Reflectors


The customer manufactures automotive reflectors that function in pairs (left and right). The reflectors consist of a welded front and back panel with a slight air space between. The need was to concurrently test each pair for leakage. As an in-process test, it is also important that the test be semi-automated, quick and easy to perform.

A TME Solution-C Vacuum Chamber Leak Test system was designed consisting of a two-port vacuum chamber tester paired with a semi-automated test fixture.

The test fixture is comprised of a fixed base with two custom machined cavities and rubber O-ring seals to conform to the size and shape of the test items. The fixture is operated by means of a two-hand anti-tie-down start switch system for operator safety. The test is performed within a chamber that uses vacuum to create a differential pressure on the test part and detect leakage from the test part into the chamber. If air from the part enters the chamber an increase in chamber pressure indicates the leakage. The Solution leak tester detects this leakage of air ("vacuum decay"), thus indicating a leak. The test instrument is equipped with an internal vacuum generator.

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Pressure Decay Leak Testing of Brake Caliper Assemblies

A manufacturer of brake caliper assemblies needed to perform a high pressure leak test on two configurations of the assemblies.

The leak test system provided consists of the TME Solution leak tester (high pressure model) and a test fixture adjustable to accommodate two configurations of brake caliper assemblies. The test fixture is designed to restrain the caliper actuation cylinders when pressurized. The caliper is connected to the TME Solution test instrument via a manually actuated seal connector. The test fixture accommodates other configurations of brake caliper assembly by removing and replacing the central fixture body.

When the operator attaches the instrument's air input line to the caliper and presses the "Start" button, the TME Solution tester will automatically perform a pressure decay leak test on the part. A decay of pressure beyond the customer's acceptable test limit indicates a failed leak test actuating a red indicator and available alarm.

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Leak and Backpressure Occlusion Test of Automotive Part with Check Valve

A company that manufactures automotive parts needed a leak test method for a part containing passages connected by a check valve. It was necessary to test both the integrity of the part and to confirm that the check valve was operating properly.

A two-port TME Solution leak and flow test instrument was modified to perform three linked tests on the part:
1. A standard pressure decay leak test. In this test, the inlet and outlet ports were blocked and the part was pressurized on both sides of the check valve. Decay in the pressure during the test time indicates a leak in the housing of the part.
2. A backpressure occlusion test at a higher pressure on one side of the check valve to confirm that it is opening properly. In this test the outlet ports are blocked and pressure is applied to one side of the check valve.
3. A second backpressure occlusion test on the other side of the check valve at a lower pressure to confirm that it is closed. In this test pressure is applied to the other side of the check valve.
The instrument cycles through the three tests and reports the test results on the screen.

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Vacuum Decay Leak Testing for Brake Housings

An automotive supplier manufactures brake housings. A leak test system was needed to provide vacuum decay leak tests on two configurations of the brake housings. The test parameters included a very long test time at a very minimal vacuum level.

TME designed a custom test system comprised of a TME Solution single port Leak Tester, a test fixture that will accommodate either of the part configurations, and an external vacuum pump. The fixture is comprised of a moveable test platform on which the test part fits over a central base. By placing manual clamping pressure on the test part, a seal is completed at the base of the housing. The housing is then evacuated to the desired vacuum level by the external vacuum pump and the test is run. At the end of the extended test time (during which the external vacuum pump is turned off), the Solution test instrument will display the vacuum decay that has taken place during the test time. A green "Pass" light will indicate a good part, and a red "Fail" light will indicate a leaking part.

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Testing Radiator Tubes for Leaks

The customer manufactures radiator tubes and needed a leak test system. The test required an 80-psig test pressure and a very fast cycle time in order to keep up with automated production of 370 units per hour. The TME Solution™ with four port concurrent leak testing and Memory Reference Curve technology was interfaced with an enclosed fixture that would hold four tubes. The Memory Reference Curve is a technology that allows the operator to store the decay curve of an acceptable unit in the instrument's memory. The TME Solution™ then tests four tubes concurrently, compares their decay curve with the reference in its memory and identifies any parts that are leaking with an audible and visual failure indicator. Testing at 80 psig normally requires an extended stabilization time, but using the Memory Reference Curve all but eliminates this time, making possible a five second cycle time. This cut the customer's overall test time in half.

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Leak Testing Large Capacity Tanks

A company required a method for leak testing large capacity tanks after hydrofluoric acid washdown.

This TME Solution test instrument is designed to detect a leak in the tank using the pressure decay method. A testing cap was specially designed to seal the tank and allow it to be pressurized. After the washdown the sealed tank was further pressurized to a preset test pressure and held at that pressure for a preset test time. Decay of the pressure beyond the acceptable limit indicates that the tank fails the leak test. The tank was then to be vented, the test cap removed, and disposition made of the tank as per the customer's process.

The testing cap consisted of a threaded cap designed with acid-resistant materials to provide a leak-tight seal to the inlet pipe of the tank to be tested. This cap was provided with a quick-disconnect containing a sealing valve that is used to pressurize the tank before washdown and again to perform a pressure decay leak test after washdown. Two connector lines were provided, one to enable initial pressurization from the customer's regulated air supply before washdown and for venting if necessary, and one to enable the pressure decay leak test and post-test venting of the tank. Also provided was a gauging connector that could be connected to the testing cap after the tank has been pressurized if confirmation of tank pressure is necessary.

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