A check valve, clack valve, non-return valve or one-way valve is a valve that normally allows fluid (liquid or gas) to flow through it in only one direction. Check valves are two-port valves, meaning they have two openings in the body, one for fluid to enter and the other for fluid to leave.
Some causes of cold intolerance are: 1  Anemia. 2  Anorexia nervosa. 3  Blood vessel problems, such as Raynaud phenomenon.  Chronic severe 1  illness. General poor health.  Underactive thyroid 1  (hypothyroidism) Problem with the hypothalamus (a part of the brain that controls many body functions, including body temperature)
Rating Newest Oldest. Best Answer: There are many types of virus that can cause a cold, so no cold is identical to another. In addition, our ability to fight a cold varies from person to person and time to time. So colds can last for anything between a couple of days to well over a week of sore throat, fever, blocked nose and other miserable symptoms. But as a rough guide, colds have usually run the worst of their course within a week, and you should certainly be well on the way to recovery by ten days.