The liquid ammonia sampler achieves safe and accurate liquid ammonia sampling through pressure control, valve operation, and separation devices. The core principles include pressure differential driven injection, quantitative separation, and temperature control. During sampling, the pressure difference between liquid ammonia and the air inside the steel cylinder is utilized to control the injection amount of liquid ammonia by accurately opening the valve. At low temperatures (boiling point of liquid ammonia -33.34 ℃), liquid ammonia rapidly vaporizes, and the internal design of the steel cylinder ensures a smooth injection process.
Operating Specifications
Equipment inspection: Confirm the airtightness of the sampler, with a focus on checking the valves, interfaces, and sealing gaskets. If aging or cracks are found, they should be replaced immediately.
Check whether pressure gauges, flow meters, and other instruments are within their valid calibration period to ensure accurate display.
The sampling bottle needs to undergo pressure testing and drying treatment to avoid contamination caused by residual moisture and impurities.
Protective equipment: Operators must wear chemical protective clothing, gas masks, acid and alkali resistant gloves, and goggles. Direct contact with equipment without protection is strictly prohibited.
Emergency eye wash stations, sprinkler systems, and neutralizing agents (such as dilute sulfuric acid solution) should be prepared at the sampling site to ensure that emergency facilities can be accessed within 30 seconds.
System replacement: After connecting the sampling pipeline, first open the exhaust valve of the sampler and introduce nitrogen or dry compressed air to replace the air in the pipeline. The replacement time should not be less than 5 minutes to prevent impurities from reacting with liquid ammonia.
After the replacement is completed, slowly open the sampling valve and control the flow rate at 0.5-1L/min to avoid pipeline impact and leakage caused by too fast a flow rate.
Sampling control: Maintain a stable standing posture during the sampling process and avoid facing the sampling port directly.
Closely observe changes in the pressure gauge, and if there is a sudden drop in pressure or abnormal noise, immediately close the valve to investigate the leakage point.
After the sampling volume reaches the scale, close the sampling valve first, and then close the exhaust valve to prevent the backflow of liquid ammonia.
Sample transfer: When disconnecting the sampling bottle from the pipeline, it is necessary to first release pressure to atmospheric pressure and quickly seal the bottle mouth with a special sealing cap to avoid ammonia vapor evaporation.
The outer wall of the sampling bottle should be wiped clean with clean water to prevent residual liquid ammonia from corroding or polluting the environment.
Leakage disposal: In case of minor leakage, immediately close the upstream and downstream valves, blow with nitrogen, and replace the seals.
If the leakage is large, start the emergency plan, evacuate people, dilute the ammonia vapor with spray water, and block the leakage point.