Zahm & Nagel 5000 New Style Headspace Air Tester
Headspace “Air” Testers for Cans & Bottles
This instrument is recommended for testing air content where greater speed and accuracy is required. It is automatically adjustable to various size bottles and cans and is available in one and three liter sizes. The parts list and line drawing should be used for assembly and as a reference for ordering replacement parts.
[Note: Headspace “air” is defined as atmospheric air picked up during the brewing process. These instruments do not measure dissolved oxygen.]
To assemble, use a little lubricant on the stem of the burette (5003-25) and the level bottle (5047) and immerse the connection tubing (5052) and the rubber coupling (5046) in hot water to facilitate insertion of the tubing. Now connect the rubber coupling (5046) to the center stem of the burette and connect the other end of the coupling to the hose nipple (5057) of the Whitey valve (5055). Connect the connection tubing (5052) to the side stem of the level bottle (5047). Assemble the burette clamp (5006) around the burette and fasten in place on the support rod(5016).
Warning: Caustic Solution is used in the operation of this instrument. This solution may cause severe burns to the operator if not handled with care. Wear goggles and protective clothing while operating this instrument.
The instrument is now ready for operation but should first be tested for any gas leaks that may occur at various connections. This may be accomplished by pressurizing the instrument and applying a soapy solution to the various connections and joints. The instrument may also be submerged in a glass tank of water, and leaks observed in this manner.
The generally accepted temperature for gas analysis is 77ºF/25ºC. Therefore, it is good practice to bring samples to this temperature prior to testing. The volumes of CO² gas may be determined by taking the maximum pressure reading during the test and then, immediately after the test, inserting a laboratory thermometer into the sample and recording the temperature. The CO² content can be determined from any standard temperature/pressure relationship chart using the above information.
- Close the Whitey valve (5056), open the burette cock (5005) and put approximately 100cc’s of water in the level bottle(5047), elevating the same above the burette so as to allow the water to run down into the burette to the bottom of the calibrations.
- Close the burette cock and lower the level bottle to its stand (5050)
- Place a small beaker of water under the rubber seal (5045) and lower the cross bar (5024) so as to submerge the rubber seal in the water. Note: The cross bar is lowered by depressing the lock pates (5026) on each side of the cross bar and pushing downwards. When the lock plates are released, the cross bar will remain firmly locked in position.
- Open the Whitey valve (full). This will cause the water top be drawn upward through the Whitey valve, displacing any trapped air in the system. Tap the tubing to release air into the burette
- Close the Whitey valve and remove the beaker from the piercing needle (5042A)
- Open the burette cock and allow the water to return to the level bottle. Discard the water.
- Replace the water in the level bottle with caustic solution, filling it approximately half full. Note: Wear protective clothing and goggles when using caustic solution. A 20% solution of either Potassium Hydroxide or Sodium Hydroxide is recommended for air testing. (* A weaker solution may be used, but the tests will take longer and fewer tests can be performed.) To make a 20% solution, slowly add 100 grams of Potassium or Sodium Hydroxide crystals to 500 cc’s of distilled water and store in a sealed jar. The above solutions may also be purchased from any laboratory/chemical supply company
- Raise the level bottle to fill the burette completely and close the burette cock. To prevent overflow, the caustic trap(5079) is furnished for attachment at the top of the burette. While filling the burette, check the plastic connection tubing(5052) and work out any air bubbles that may be present
- Place the bottle or can to be tested on the base pad (5022) and lower the cross bar to the point where the rubber seal just touches the top of the container.
- Depress the lock plates and push the cross bar rapidly downwards until the container is pierced.
- Release the lock plates. The cross bar will remain locked in place with the rubber seal compressed to prevent leakage at the point of piercing. Be careful not to trip the lock plates after piercing as only a slight upward pressure on the lock plates will release the cross bar.
- Hold the instrument at the bottom of the base with the right hand while the left hand holds both the guide rod (5017)and support rod (5016). Shake the instrument with a rapid back and forth motion until maximum gauge pressure has been obtained. Note: The burette is very fragile and may break if it comes in contact with an object while shaking the instrument. Also, be sure that the level bottle and stand are located in such a manner that they do not tip over while shaking the instrument.
- Open the Whitey valve (5056) and allow gas to flow into the burette, reducing the gauge pressure to 5 psi or less. Shake the instrument a few times to allow absorption of CO² gas by the caustic solution. It is also advisable to invert the instrument and allow the gas that was released into the burette to be absorbed in the larger bottom bulb of the burette. The shaking of the instrument allows for more build up of gas in the test container and for the next release of gas into the burette.
- Open the Whitey valve and repeat the above process again. Usually eight or ten shakes are enough to remove most of the air in the sample. For very accurate work, however, the operation should be continued until a constant air reading is obtained. When making the air reading in the burette, the level bottle should be raised so as to bring the liquid in the burette and level bottle to the same level.Air Readings: If air readings tend to increase after a period of testing, the caustic solution may be diluting and should be replaced with a fresh solution. The number of tests that can be expected from the caustic solution may vary according to the strength of the solution being used.
- Close the Whitey valve and release the lock plates by pressing them in an upward direction and then raise the cross bar to a level that will allow the removal of the container.
Care of Instrument
Cleaning of the Instrument
When the tests have been completed, the instrument should be cleaned as follows:
- Close the Whitey valve and open the burette cock and allow the caustic solution to drain into the level bottle. Discard the caustic solution if it has become weak or, if still good, store in a sealed glass container for future use.
- Open the Whitey valve, fill the level bottle with warm water and raise the level bottle above the top of the burette. Fill the burette with warm water until it overflows at the caustic trap.
- Lower the level bottle and allow the water in the burette to drain through the Whitey valve and also back into the level bottle. Repeat step #2 several times or until all traces of caustic solution have been drained from the burette and fittings.
- The pressure gauge should be removed from the gauge adapter (5039), rinsed in warm water and then dried.
Note: Caustic solution will eventually discolor the Tygon™ Plastic connection tubing (5052) and also cause deterioration of the rubber coupling (5046). If this condition occurs, the parts should be replaced.
Calibration of Pressure Gauge
The pressure gauge should be tested for accuracy at the beginning of each shift. Procedures for re-calibration are sent with the instrument and are available upon request from Zahm & Nagel Co.