A compressed air system is always equipped with a pressure vessel. This is a container whose purpose is to store gases or liquids under the action of compressed air. Vessels are made of different materials. They are chosen based on the type of medium that will be stored in them. They are mainly manufactured from carbon steel powder coated on top. This is a versatile option and the cheapest. It is worth remembering that if you want to extend the life of the equipment and protect it from corrosion, you should use a protective layer with condensate and also use hot-dip galvanisation. However, buying a stainless steel pressure vessel ensures that this problem is avoided. In addition, it maintains high air purity. It is quite an expensive choice, but we are assured that the tank will serve us for years, thanks to its unique quality. In order to produce a spherical or cylindrical tank, forged or rolled parts are welded together. The lack of proper precautions can adversely affect certain properties of the steel. Current standards prescribe the use of high impact steels, particularly when operation is carried out at low temperatures. The equipment is also divided into vertical and horizontal positions. The choice depends on the amount of space available. There are different sizes and temperature ranges for the tanks. It is worth noting that the selection of the right equipment depends on the need of the specific installation, which is required by the capacity of the compressor and the receiver of the pressure value. Additional equipment to support proper operation and safety are:
- a manometer that monitors the pressure inside the unit
- safety valve to protect the tank against excess pressure
- condensate drain, which releases accumulated excess condensate
Due to the risk of accidents during operation, pressure vessels must meet all safety requirements and be notified to the UDT (Office of Technical Inspection). This allows operation in compressor units and tank installations. Production, design and operation are governed by regulations covering various parameters, including operating temperature, safety factor, susceptibility to corrosion, maximum operating pressure and minimum design temperature. The completed design is tested using ultrasonic testing, radiography and also pressure testing. In contrast, tanks used for lacquers and paints are used together with an automatic or manual gun for coating larger areas or in production. The shape of the tank depends on preference, but the most well-known are tanks made of cone, cylinder or ball parts. The most common is the cylinder with caps, which are called heads. The heads can be hemispherical or concave. In the old days, more complicated shapes were used, making it difficult to analyse the devices in terms of safety and handling. They were also much more difficult to construct. Because of the high pressures, tank failures can be very dangerous. The most commonly encountered situations include:
- use of equipment at higher (than permitted) pressures
- inadequate installation design
- corrosion
- using the tank above the permitted temperature scale
How do you look after the cylinders?
The result of such working conditions can be to put your life and the lives of your employees at risk. To ensure safety at work you should:
- do regular maintenance
- working pressure gauge on the tank
- approval by the Technical Inspection Authority
- functioning safety valve
- regular emptying of condensate from the tank
- not exceeding the pressure
