Why are acetylene cylinders only used in the upright position?

Acetylene cylinders are specifically designed to be used in the upright position to prevent acetone from being pulled out of the cylinder. Acetylene is dissolved in acetone within these cylinders under pressure, and maintaining the cylinder upright ensures that only the gas is released when the valve is opened. If the cylinder is tilted or used in a horizontal position, acetone could be expelled along with the gas, resulting in not only an inefficient gas supply but also a significant safety hazard. This is critical because acetylene is highly flammable, and the presence of acetone could lead to dangerous situations during handling or usage. Thus, the upright positioning is essential for both the safe and effective use of acetylene in various applications.