Caps and Closures FAQs

General Questions

• Do the rubber stoppers in the Wheaton^® range contain natural rubber latex?

  Stoppers made from natural red rubber and stoppers made from chlorobutyl-isoprene blend contain natural rubber latex. All of the other stoppers are latex-free. This is also the case for lyophilization stoppers.

• What is the maximum dry-heat temperature that Wheaton^® stoppers can withstand?

  Stoppers made from silicone or FKM can withstand dry-heat temperatures up to 200°C. All of the other stoppers can withstand dry-heat temperatures up to 100°C. It should be noted that all of the stoppers can be steam autoclaved at 121°C. The given temperature limits are for dry heat environments.

• Which Wheaton^® stopper is usually used when packaging contact lenses in serum vials?

  Our item 224100-178 is made from silicone and was originally referred to as the contact lens stopper.

• Can I steam autoclave aluminum crimp seals?

  Yes. The aluminum seals can be steam autoclaved at 121°C at 15 psi for 30 minutes.

• Which cap lining material provides the best gas/moisture barrier properties?

  If compatible with the product, a metal foil liner would provide the best barrier to gas and moisture transmission.

Equipment

• What tubing size and pump settings should I use to get the best accuracy when using Omnispense peristaltic pumps?

  The best accuracy can be obtained by using the smallest size tubing ID and the slowest pump speed setting. Unfortunately, this selection takes the longest to dispense the requested volume. Each user must decide on the dispense time vs accuracy that best suits their requirements.

• What is the easiest way to attach the glass sinkers to the peristaltic pump tubing?

  Dipping the end of the tubing in warm water should make it easier to attach the glass sinker.

• How many pump heads can be attached to the Omnispense Elite Dispenser?

  One additional pump head can be attached (stackable pump head for 2.3 mm wall tubing - Wheaton^® item W375022).

• Can I use the handset from the Omnispense Plus Dispenser with the Omnispense Elite Dispenser?

  Yes, but it will not work as it does with the Omnispense Plus. The “Start” key on the handset will be the only working key and it will start and stop the dispense cycle. It will no longer pause a dispense cycle.

• How can I obtain the best calibration possible when using the Unispense Pro Dispenser?

  The manual states “for best results, the pump should run for a minimum of 15 seconds. The longer the run time the more accurate the calibration”. This provides the unit with more rotation/ml data to use in its calculations. Also, set the calibration motor speed to what will more closely match the actual dispensing motor speed. The breaking dynamics of the motor is affected by the speed of the motor. This also holds true for the Omnispense Elite Dispenser.

• How can I remove a stored process parameter that is no longer being used from a register?

  A stored process parameter cannot be erased. However it can be over-written by entering zeros for the functions, which would alert the user the stored process parameter is not usable. This is also true for the Omnispense Elite Dispenser.

• What are the part numbers for the replacement drive belts for the 9-Deck Wheaton^® Modular Roller Apparatus 348968-A?

  The (2) motor belts are Wheaton^® item number I052719. The (16) deck belts are Wheaton^® item number I052734. The (36) stretch belts are Wheaton^® item I052737.

• Which Roller Apparatus will provide a digital readout for the bottle speed?

  Presently, only our R2P Roller Systems provide a digital display of the bottle speed.

• On the large roller bottle systems, what is the difference between “modular” and “production” spacing?

  The production spacing is designed for maximizing space. The spacing between roller decks is shorter. This means it is a bit more difficult to move bottles in and out of the deck, but more bottles can be accommodated with the same space. The modular spacing makes it easier to insert and remove bottles.

• What is the maximum weight that can be placed on the Roll-In Incubator shelf?

  36kg

• What is the difference between the Wheaton^® Cell Optimizer Bioreactor System and the Wheaton^® Mini-Pilot Plant Bioreactor System?

  The only difference is the vessel size. The smaller vessels (3 liter or less) are called Optimizer Systems and the larger vessels (10 – 45 liters) are called Mini-Pilot Systems.

• Can I convert my 11mm Hand Crimper so it crimps 20mm seals?

  Although it is possible to convert your crimper by replacing the internal crimping jaws and plunger, it is not advisable. Manufacturing uses special fixtures to help assemble the components.

• My crimping head will not close around the 20mm aluminum seals with the plastic closure.

  There is a special crimping head for the aluminum seals with the plastic closures that is often termed a “Flip-Off” crimping head. Please make certain your crimping head has the jaws with the internal recess for the plastic button that is part of the seal.

• How can I determine what size crimper I have if there are no markings on the crimper?

  The easiest way would be to measure the diameter of the plunger. The plunger is approximately the same diameter as the seal and contacts the top of the aluminum seal during a crimping operation.

• What is the most likely cause of indentations on the sides of a crimped aluminum seal?

  Usually it is caused by over-tightening. Try adjusting the crimping tool for a looser seal.

• Are the peristaltic pump silicone tubing assemblies steam autoclavable?

  Yes. The recommended autoclave cycle is 121°C at 15 PSI for 20 minutes. It is recommended to flush the tubing with distilled water just prior to autoclaving.

• Can the peristaltic pump silicone tubing be sterilized by irradiation?

  Yes. The suggested dosage is 25 kGy. The polypropylene nozzles and glass sinkers that attach to the tubing cannot be irradiated.