The tanks are used for location of the propellant components (oxidizer or fuel).
Structurally, the tanks are cylinders that consist of:
- a body;
- an upper and a lower bottoms;
- devices inside the tank.
The tanks can be made in the form of individual sections for location of oxidizer and fuel, and in the form of a single propellant section where the oxidizer and fuel manifolds are separated by an intermediate bottom. The typical structures of the tanks are presented in fig. 1-4.
The following equipment is located inside the tanks:
- the sensors of the propellant flow rate control system;
- the sensors of the filling level control system;
- the intaking devices for cavitation-free propellant flow rate;
- the dampers (lateral and longitudinal);
- the devices of uniform gas spraying for tanks pressurization etc.
The tanks are equipped with hatches for mounting of the structural elements located inside the tanks.
The grooves of the harness and the pipelines are made on the external side of the tanks.
The following materials are used for production of the tanks:
- aluminium alloys AMg 6, AMg 6N, AMg 6M, AMg 6NN;
- steels 12X18 N10T, 12X18 N10T-VD.
The materials are subject to ultrasonic testing for finding the internal defects in metal.
Bimetallic adapters are used for transition from the aluminium elements of the structure to the steel elements. The adapters are made by stamping of bimetallic sheets or by friction welding. The bodies of the tanks and load-carrying structures are made of "wafer" shells (fig. 5) produced of the plates of necessary diameter and welded by arc or by resistance welding.
After that, mechanical milling of the cells is performed using machines with the software and a follow-up system that controls the spread of the thickness in the production process.
At present, the tanks of 14 m³ - 210 m³ volume are produced with 1500 mm, 3000 mm, 3900 mm diameters of the shells made of the plates of 20-31.5 mm thickness.