1Tedra gas sampling bagPrecautions for use
Operating Specifications
On/off valve operation: When the valve stem rotates clockwise to the end, it is closed, and when it rotates counterclockwise to the end, it is open. It can only be fully opened or fully closed and cannot adjust the flow rate.
Inflation pressure: The inflation pressure should not exceed 3KPa. It can be visually observed that the airbag is fully inflated, but it is not very tight when pressed with fingers. Overpressure filling may cause the airbag to burst and be damaged.
Usage temperature: The general usage temperature range is -30 ℃ to+110 ℃, but the temperature range varies for different interface types, such as PTFE interface from -60 ℃ to+150 ℃, and plug valve interface from -20 ℃ to+80 ℃.
Keep away from sources of fire and sharp objects: When storing and using, keep away from open flames and high temperatures, and avoid contact with hard objects to prevent puncturing the membrane material.
Sampling and Preservation
Sampling volume: When sampling and cleaning, please do not exceed 80% of the calibrated volume. Taking a 1L sampling bag as an example, the sampling volume should not exceed 0.8L.
Storage time: The storage time of gas samples in the sampling bag should not be too long, which is related to the detection time limit, gas composition type, temperature and humidity, pressure, etc. required for experimental analysis. Generally speaking, inert pure gas can be used as a temporary storage container, and it is recommended to store it for no more than 72 hours; It is recommended to store ordinary standard gases, flue gases, environmental atmospheres, etc. for no more than 24 hours.
Light shielded storage: For low concentration volatile organic compounds (VOCs) such as chlorinated hydrocarbons, it is recommended to use black sampling bags, which can effectively avoid changes in components caused by photocatalytic oxidation and ensure the authenticity of the sample.
Cleaning and repeated use
Cleaning method: Before using the new sampling bag, rinse it with high-purity nitrogen 3-5 times, and let it stand for 30 minutes after each rinse. The reusable sampling bag needs to be vacuum cleaned to a vacuum degree of -0.1MPa, maintained for 10 minutes, and then filled with high-purity nitrogen gas. Repeat this process three times.
Reuse requirement: The sampling bag can be reused, but it must undergo multiple replacements and cleaning. It is recommended to collect the same type of sample from the same sampling bag and not mix them together. For sampling components with concentrations of ppbv and high residual components, it is recommended to use them after long-term ventilation aging. By repeatedly inflating and exhausting pure air and high-purity nitrogen, the aging effect will be better at 60 ℃.
Transportation and Storage
Transportation requirements: Tedra sampling bags can be transported without being lowered and packaged with strict protection. Due to the lack of elasticity of the sampling bag, it may be subjected to compression and collision during transportation. For safety reasons, it is recommended that the inflation amount not exceed 50% of its own volume.
Storage conditions: Unused bags should be stored in a clean environment and placed in sealed outer bags to prevent the adsorption of pollutants.
Interface and Connection
Interface connection: Various interfaces should be connected to instruments, equipment, and devices using corresponding soft rubber hoses for transition.
Sampling method: Needle sampling can be used, and a high elasticity silicone rubber sampling pad is used for needle sampling. When the needle is pulled out, immediately pinch the sampling pad slightly to facilitate the closure of the puncture site and ensure airtightness.
2、 Frequently Asked Questions and Answers
What should I do if the sampling bag leaks?
Inspection method: Inflate the sampling bag under pressure overnight, and check the pressure the next day to determine if there is any air leakage.
Solution: The leaking sampling bag cannot be used for sampling. If repair is required, please contact the supplier.
How to deal with high background values in sampling bags?
Initial use handling: It is recommended to fill the sampling bag with 80% clean air or high-purity nitrogen and repeatedly inflate and exhaust 2-3 times during initial use.
Sampling and processing of trace components: For sampling of trace components, it is recommended to inflate the sampling bag and perform 50 ℃ constant temperature aging for 2-3 hours. If the background is still high after the first three steps and cannot meet the sampling requirements, it is recommended to perform dynamic aging under humidified conditions and prolong the aging time until the background drops to a suitable concentration.
Can the sampling bag collect corrosive gases?
Suggestion for selection: When collecting or storing corrosive gases, it is recommended to choose full plastic switch valve airbags.Tedra gas sampling bagCan be used to collect and preserve various corrosive gaseous and liquid samples.
Can the sampling bag be mailed?
Mailing requirement: The Tedra sampling bag can be transported without being lowered and packaged with strict protection.