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Introduction

The following technique was developped with an aim of controlling the accuracy of measurement techniques of NH₃ concentration used within animal housings. Thus to check the signal of a censor or to compare two different sensors.

the principle consist in pouring ina container of a known dimension and capacity a liquid containing ammonia in solution with a pH and a temperature given while preserving a known volume of air above the surface of the liquid. One ventilates the air above the liquid in a controlled way. The quantity of ammonia contained in the outgoing air of the container passes by the censor to control, and in a sulphuric acid solution of a known title and volume in the presence of an acido-basic indicator (orange methyl).

By knowing the heat-transferring surface, the ventilation flow, the normality and the volume of the sulphuric acid used as well as the time of neutralization, one can calculate the ammonia concentration of the outgoing air of the container as well as the ammonia emission at the liquids surface.

Equipment

(The final assembly will represent the figure below):

• Circuit of compressed air or pump with controlled flow
• Adjustable pressure reducer between 0 and 5 bars
• Stopping Valve
• Manifold for connections with several containers
• Standard Flowmeter rotameter or capillary, with control valve
• Scale of adjustment from 0 to 1 l/min or 0 to 10 l/min
• Cylindrical container (polypropylene can of 35 liters or polypropylene barrel of 80 liters with closing seals tight under a pressure of approximately 0.05bar
• Flexible PVC Tubes diameter inside 3 mm and 5 mm
• Connections for these tubes: normal connections and connections “T”
• Sample Tubes: capacity 50ml, diameter 20 to 22 mm
• Gauged Pipettes two graduations 1,2,5 and 10 ml
• Graduated flasks, graduated test-tubes and laboratory balances
• Bottle, feet, grips, nuts , stoppers, etc
• Equipment to be checked

Guideline details

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