Development Report Walker Barrier 10 Ergoclean Gloveport Interface And Single Piece Gauntlet Performance Testing March 25, 2005 Revised August 21, 2007 Dynamic Design Pharma, Inc.
1. Walker Barrier Gloveport Interface The GIT-LC glove integrity tester must be capable of interfacing to all standard gloveport designs in the industry. One of these designs is Walker Barrier s Ergoclean standard 10 inch molded gloveport. 1.1. Gloveport part number: GPA-UL-10VL 10 inch molded Ergoclean gloveport assembly. 1.2. Sealing problems with standard design Although sealing very well from inside the isolator, the gloveport has a sealing issue when pressurized from the outside to inflate the glove. Figure 1 shows the leak path. Figure 1. Leak path in standard gloveport design Comments: 1.2.1. The leak path shown clearly does not allow the simple attachment of a sealing plate to the outside of the gloveport. 1.2.2. The small O ring that schematically should yield the required seal, is not reliable enough to assure a good seal, particularly along the straight sides of the gloveport. 1.3. Solution of sealing problem with standard design 1.3.1. A simple modification to the standard design gloveport corrects this sealing problem. Figure 2 shows the modification. Page 2 of 11
ADDED "O" RING Figure 2. - Leak path elimination with standard O ring 1.3.2. The added O ring is a standard 6 mm cord diameter silicone seal and it is bonded to the gloveport outer ring using clear silicone RTV adhesive. 1.3.3. Simple tightening of the top and bottom clamping screws was found to be insufficient to assure a reliable seal. 1.3.4. Clamping force all around the circumference of the gloveport is necessary. See interface design for means of meeting such requirement. 1.4. Interface design Figure 3 shows a gloveport interface design that yields good clamping force all around the gloveport, only requires only the addition of the above mentioned O ring to the gloveport, making field retrofit of existing systems quite simple. Page 3 of 11
INTERFACE ASSEMBLY ADDED CLAMPING PLATE LOCKDOWN T-SCREWS SEAL ADDED "O" RING Figure 3. - Gloveport interface design 1.4.1. The interface plate assembly clamps onto the outer body of the gloveport with six Tee-screws located around the circumference of the gloveport. 1.4.2. A stainless steel clamping plate is sandwiched between the isolator wall and the gloveport external ring. A silicone gasket may be required for those applications where the isolator wall is made of glass. 1.4.3. The tightening action of the Tee-screws compresses the added O ring and the interface plate O ring with a resulting reliable seal. 1.5. Description of mock up A mock up of the above interface was fabricated to prove the concept. 1.5.1. The gloveport was mounted on a ½ inch thick polycarbonate plate. Installed per manufacturer s instructions. 1.5.2. A 6mm O ring was bonded to the gloveport outer ring using clear silicone RTV adhesive. 1.5.3. The interface plate was fabricated of ½ thick clear polycarbonate and a 6mm O ring was bonded to its face to seal up against the gloveport outer ring. 1.5.4. Pneumatic connections were added to the interface plate to connect ot the GIT-LC tester. Page 4 of 11
1.5.5. To simulate the clamping plate, six each 3/8-16 studs were attached to the mounting plate. Cross bars between the studs were used to apply clamping force onto the interface plate. Page 5 of 11
2. Gloveport Interface Figure 4. - Mock up of interface 1.5.6. Repeated testing of the mock up proved that the design described above is solid in that it will deliver a simple, consistent and reliable interface to the gloveport under test. 1.5.7. The mock up was attached to the gloveport numerous times and it never failed to produce predictable results after each connection. 2.1. Figure 5.0 shows the Ergoclean gloveport connected to the GIT-LCA glove integrity tester while in operation. 2.2. Figure 6.0 shows the gloveport as modified to accept the gloveport interface. Notice the blue clamping ring that is added to the assembly and features the threaded hole onto which the interface is attached. 2.3. Figure 7.0 shows the interface installed onto the gloveport. Visible are the pneumatic connections to the glove tester and the holding handle to facilitate interface installation. Page 6 of 11
Figure 5.0 Page 7 of 11
Figure 6.0 Page 8 of 11
Figure 7.0 Page 9 of 11
3. Gauntlet testing Positive pressure Testing of the single piece gauntlet under positive pressure, meaning that the isolator is under negative pressure for containment applications. 3.1. Two different gauntlet types were tested. 3.1.1. Hypolon 10 inch gauntlet, color white. Somewhat stiff gauntlet that seems to easily take set, for example folds, pleats. Somewhat smooth outer and inner surfaces. 3.1.2. Neoprene 10 inch gauntlet, color black. Rubbery material, dull on hand side and shiny and sticky on the isolator side. Very pliable, does not crease easily. 3.2. Issues found 3.2.1. Because of the geometry, the main body of the gauntlet continues to expand (stretch) once pressure is applied. As a result, leak testing can only be performed at low pressure values. 3.2.2. Confining the body of the gauntlet resolves this problem but is not reasonable for positive pressure testing (gauntlet located inside the isolator). On the other hand, it is possible to achieve that in negative pressure mode (gauntlet outside the isolator inside a vacuum chamber). See note on this subject later. 3.2.3. Because of the low test pressure, the gauntlet s is slow in taking the required stable shape that is necessary for a reliable leak test. A stabilization pressure sequence, at a higher pressure than the leak test pressure, was added to take place before the leak test sequence. 3.3. Process parameters 3.3.1. Test Pressure: 350 pa 3.3.2. Stabilization Pressure: 420 pa (20% higher than leak test pressure) 3.3.3. Leak test flow rate: 50 Sccm 3.3.4. Inflation time: 60 seconds approx. (see note 1). 3.3.5. Pressure stabilization time: 60 seconds 3.3.6. Leak test time: 240 seconds 3.3.7. Total leak test time: 360 seconds (6 minutes) Note 1: This time indicates starting from a totally deflated gauntlet. This time can also be greatly reduced by adding an inflating ring to the gloveport interface hardware. 3.4. Performance testing results 3.4.1. Claimed orifice size detection capability: 250 um (0.010inch) diameter 3.4.2. Confidence level of no false positives: > 3 sigma (99%) 3.4.3. Confidence level of hole detection: > 4 sigma (100%) Page 10 of 11
Note: The above confidence levels and claimed detection capability are very conservative. The process parameters can be adjusted to slightly reduce the confidence level and achieve either a shorter cycle time or a reduction of the size of the orifice that the system will reliably detect. 4. Gauntlet testing Negative pressure Testing the gauntlet under negative pressure, for aseptic applications that have positive pressure inside the isolator, offers the possibility of drastically improving the system s performance. 4.1. The gauntlet is reversed to the outside of the isolator and placed inside a vacuum chamber. 4.2. The vacuum chamber includes restraining surfaces that conform to the gauntlet body (cone). 4.3. Restraining surfaces must be of porous material. 4.4. Preliminary testing confirms that much higher pressure levels can be applied to a restrained gauntlet. 4.5. Performance capability should approach that of a standard glove in a cuff/sleeve/glove system 4.6. For reference, such performance is: 4.6.1. Orifice detection size: 100 um (0.004 ) diameter 4.6.2. Pressurization time: 60 seconds 4.6.3. Leak test time: 120 seconds 4.6.4. Total leak test cycle time: 120 seconds (3 minutes) 4.7. Development of this type of interface has not been completed at this time. 5. Summary Based on the above, the following points can be made. 5.1. A reliable interface to Carlisle Ergoclean gloveports has been developed and the concept proven. 5.2. Gauntlet testing under positive pressure (isolator negative) can be reliably conducted by the system, given the performance and parameter specification listed above. Page 11 of 11