It means he thinks you are lovely. that's a beautiful compliment, but it doesnt necessarily have to mean more than that. It means he secretly likes you and doesn't have the courage to tell you that he likes you to your face. could just be flirting to see what you're reaction would be like.
Medical air is also used during anesthesia as a substitute for nitrous oxide to reduce the high concentration of oxygen exposure. While the source of medical air may be a manifold with a bank of compressed air cylinders, most hospitals use a compressor system. This article will refer to installations with air compressors. An illustration of a typical medical air plant is provided for your reference throughout this article's discussion.
The purpose of the compressor is to circulate the refrigerant in the system under pressure, this concentrates the heat it contains. At the compressor, the low pressure gas is changed to high pressure gas. This pressure buildup can only be accomplished by having a restriction in the high pressure side of the system. This is a small valve located in the expansion valve.