Medical Bag & Bladder Leak Testing
The customer needed to perform 100% testing of various sizes of IV Bags for leakage. They had been using a photohelic pressure gauge based test instrument which would pressurize the part to a single pressure for a very lengthy fill step time. Afterward, the bag was isolated from the pressure source and the test step would begin by measuring the pressure within the Bag under test. The Bag would only fail if the gross pressure inside it, as indicated by the photohelic gauge needle, dropped below a minimum overall pressure as set by a limit flag on their test system by the end of the test step. The customer was unhappy with:
CTS Tooling Solution:
To alleviate both the excessive volume and most of the compliance/stretch problems, CTS designed a single restraining plate fixture consisting of two rigid metal plates which spaced closely together. The IV Bag is slid between these two restraining plates prior to the start of the test process. This allowed a dramatic reduction of the volume of air required to fill the part to target pressure. Also, the fixture limited much of the elastic compliance/stretch of the Bag while at test pressure. The inside surfaces of each restraining plate was lined with a porous material so as to be sure not to allow any sidewall leaks to be masked by the restraining plates when the Bag was inflated.
CTS Instrument Solution:
CTS utilized their Sentinel Blackbelt leak test instrument to perform the test. The Blackbelt allows storage of up to 99 programs which allowed the customer to have pre-programmed unique setups (including all test timers and limits) for each model of IV Bag. This test was performed using a Parent test program which managed two sequential child programs to accomplish the following: Slightly over-inflate the Bag to pre stretch the bag, followed immediately by reducing to target test pressure via the target test pressure regulator and then performing the pressure decay test on the part.
Other Features of this Application:
A single electronic regulator could have been used instead of the two manual regulators on the Blackbelt instrument.
The restraining plate fixture was installed with multiple CTS OD Connects with stainless steel ID support mandrels to automatically seal on the soft port tubes welded into the header of the Bag and mate it to the test port of the instrument.
If the part passes the leak test, the Connects automatically release the part to the operator. If the test fails, the part is securely held in the Connects and requires a reset action of some kind (operator pressing the Stop button or requiring a key reset) to unlock the part. This action is used to prevent the inadvertent placement of the failed Bags into the passed-part area.
This same technology is often used in testing: