The safety valve is a special valve that is in a normally closed state under the action of external force. When the pressure of the medium in the equipment or pipeline rises beyond the specified value, it discharges the medium to the outside of the system to prevent the medium pressure in the pipeli

1. Intake disorders: Respiratory diseases such as asthma are typical cases of hypoxia caused by intake disorders, which will seriously affect life, study and work when they occur. In addition, oxygen-deficient environments such as basements with no ventilation and indoor spaces without ventilation i

There is such a class of gases, which are very inert in the atmosphere and difficult to react with other substances to form compounds. They are called noble gases, also known as noble gases. Next we will introduce the least rare of the rare gases, argon (Ar). Argon is colorless and odorless. It cann

1. The advantage of Ar+He argon is that the arc combustion is very stable and the spatter is extremely small. The advantages of helium are high arc temperature, high heat input to the base metal, and fast welding speed. The advantages of both can be obtained by adding a certain amount of helium with