A manometer It is a device used to measure the Pressure : that is, the physical magnitude that reflects the force exerted by a body on a surface unit. With these instruments it is possible to check the pressure of a gas or a liquid.
Many pressure gauges are usually responsible for registering the gauge pressure which is the difference between the actual pressure and the atmospheric pressure . For this they take the atmospheric pressure as a reference and then determine the difference between the actual fluid pressure. It should be noted that the atmospheric pressure is the pressure made by the atmosphere on the bodies that are immersed in it: at sea level, its normal value is of 1013 mbar or 760 mm Hg .
There are two large types of pressure gauges. The analog gauges exhibit the pressure measured by a needle, while the digital pressure gauges they have an LCD screen where they present the result .
Pressure gauges are used, for example, to measure the pressure of tires of the vehicles. Checking this pressure is very important: the tires must have the pressure suggested by the manufacturer to ensure their adhesion to the pavement, avoid excessive wear and not encourage excessive consumption of gas . Since the tires lose pressure gradually but steadily, it is essential to appeal to a pressure gauge to perform the check-up periodically.
To measure the blood pressure , meanwhile, a tensiometer or blood pressure cuff . It is an element that has a pressure gauge, a stethoscope and an inflatable bracelet and is used to record diastolic pressure and systolic pressure.