Case Studies:
Pressure Decay Testing of Cast Housings with Multiple Orifices
Four-Up Pressure Decay Chamber Testing of Solenoids
Non-Destructive Vacuum Decay Leak Test Fixture for Cast Housings
Multiple Use, Versatile Pressure/Vacuum Decay Tester
Concurrent Pressure Decay Leak Tests on Paired EGR Valve Housings
Pressure Decay Testing of Cast Housings with Multiple Orifices
 The customer needed a means to leak test aluminum castings at two stages of manufacture: unassembled (with various orifices), and after assembly (with only one unsealed orifice), identifying porosity, cracks, pits, and other potential casting failures
TME proposed a system comprised of a TME Solution Leak Tester combined with a semi-automatic, single application fixture. When testing the unassembled casting, the test part is inserted into the fixture, pneumatic cylinders automatically seal the orifices and the item is pressurized. If there is a leak anywhere in the assembly, air will leak through, lowering the internal pressure. The Solution leak tester detects this leakage of air ("pressure decay"), thus indicating a leak. To test the assembled casting, a shut-off valve on the fixture is closed, disabling specific sealing cylinders for orifices that have been sealed during the assembly of the part, leaving active only the cylinder that will seal the remaining orifice.
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Four-Up Pressure Decay Chamber Testing of Solenoids
 A manufacturer of solenoids requested a test system designed to concurrently test four solenoids for leakage and mark the "good" parts after testing. The pressure decay test must challenge two "O" rings inside the body of the solenoid. It was important that test time be minimized and it was also required that any failed parts be "locked" in place until released by a supervisor. In addition, it was necessary that all test data be transmitted by Ethernet to a LAN.
The TME Solution four port leak tester with an Ethernet adapter card was combined with a custom test fixture designed to perform a pressure decay chamber leak test on the solenoids. A test chamber is created by inserting the plunger end of the solenoid into a double-D shaped cavity with a rubber sealing ring that creates a sealed air space when the solenoid is firmly seated. This chamber encloses the plunger area of the solenoid, and the chamber is then pressurized. If the "O" rings inside the solenoid body do not leak, the pressure inside the test chamber does not drop, but if the "O" rings allow air to leak through the body of the solenoid, it will leak through the base to atmosphere and the test instrument will record a drop in pressure in the test chamber, thus identifying a leak. "Good" parts are marked with a slight dimple on the side of the solenoid body, and "reject" parts are locked into the test station until a manager unlocks the station with a key.
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Non-Destructive Vacuum Decay Leak Test Fixture for Cast Housings
 A manufacturer of cast aluminum housings needed a cost effective, easy to use, reliable and sensitive means to a perform vacuum decay leak test. The system would need to be adaptable to accommodate future configurations of the housing.
A test system was designed using the TME Worker vacuum Leak Tester and a custom designed semi-automatic, single application fixture. The fixture is equipped with a removable test module so other housing configurations can be tested using test modules provided by the end user. The system was also provided with two calibration sub-assemblies with calibrated leaks of 1.0 cc/min @ -2.8 psi and 2.1 cc/min @ -2.8 psi at the customer's request
Once the test part is inserted into the fixture and the test begun, pneumatic cylinders automatically seal the part from three directions and the item is evacuated by means of the instrument's internal vacuum source. If there is a leak anywhere in the assembly, air will leak into the test item, raising the internal pressure. The Worker leak tester detects this leakage of air ("vacuum decay"), thus indicating a leak.
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Multiple Use, Versatile Pressure/Vacuum Decay Tester
 A company that manufactures a variety of electronic components required a test instrument with the flexibility to perform either vacuum or pressure decay leak tests, both individually and in linked sequence.
 The TME Solution model was equipped with two control regulators, one controlling tests which use positive gauge pressure (0.5 to 15.0 psig), and the other controlling tests which use vacuum (negative gauge pressure, 1.0 to 25 inHg). The regulators are individually set from the instrument's display menu. The instrument was also equipped with a switching valve that allows the "linking" and operation of two different test modes, thus enabling a wide variety of uses for the customer.
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Concurrent Pressure Decay Leak Tests on Paired EGR Valve Housings
 This TME Solution Leak Test System is designed to perform a pressure decay test on the right and left sides of EGR valve housings. The test is performed concurrently on both sides in a semi-automated test fixture that seals housing outlets, pressurizes the housings, and tests for decay of the pressure inside the valve housings. The semi-automated fixture is designed with a two-hand anti-tie-down start mechanism for operator safety. After completion of the leak tests, GOOD parts are automatically marked before the test parts are released by the fixture. In addition to the concurrent testing of paired housing sets, the test system is programmable to test one side or the other independently.
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