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)
Cold weather conditions play no role except as mentioned below about absolute humidity levels in the winter. One of the expert scientists (Bill Nye) said that you can not catch a cold from being cold; you catch a cold from germs and being cold has nothing to do with it.Plenty of tests have been conducted proving this.old weather conditions play no role except as mentioned below about absolute humidity levels in the winter. One of the expert scientists (Bill Nye) said that you can not catch a cold from being cold; you catch a cold from germs and being cold has nothing to do with it. Plenty of tests have been conducted proving this.