Innovative DUO COMB® pumping station and tank shells of glass composite
Glass composite bodies of pumping stations are made of cylindrically shaped elements of glass plastic composite that are produced by using modified glass fiber forming technology. The process allows to make a Duo Comb® wall which is reinforced with internal stiffeners (internal stiffening ribs) and provides the necessary mechanical resistance of the pumping station housings under heavy loads caused by the soil and ground water pressure.
Duo Comb® wall advantages:
- the glass composite housing is stiffer and stronger, can be used in deeper depths and bigger diameter pumping stations (bending stress fracture of fibreglass Duo Comb® composite, compared with glass plastic, increases up to 1.7 to 2.3 times, and decay deflection decreases 1.8 -2.6 times – increasing the strength and flexural rigidity of the composite structure);
- twice the protection against leakage (due to the improved technological process at internal stiffening ribs, the strength and stiffness margin of the cylindrical pumping sewage container increases by approximately 2-fold compared to standard single wall containers)
- resistance to creep deformation (when bending fracture stress is increased from 1.7 to 2.3 times, and decay deflection is reduced from 1.8 to 2.6 times, the composite creep deformation and fracture risk of the structure is dramatically reduced, while the composite dimensions remain stable for a longer period of time);
- able to deform and resistant to concentrated loads (Duo Comb® walls with internal rigidity ribs provides high reliability of design; in case of damage of any one layer of the composite wall, the design product does not lose its functional properties);
- glass composite housing is more rigid and stronger, it can be used in a greater depth and bigger diameter of pump stations;
- more plastic and lighter housing structure is resistant to shock (double housing bottom of the pumping station provides unique protection against unforeseen shock loads and allows the reconstruction of the equipped sewage pumping station in the event of damage);
- adaptability to individual needs.
Due to mechanical compression, bending and connecting loads the housing of pumping stations and storage tanks of glass-plastic often cracks, therefore, in order to make changes to the supplied equipment or to connect additional elements to the housing (ladders, measuring equipment, etc.), it is necessary to have expensive specific plastic extruding equipment.
Safe operation of pumping structures depends on mechanical properties of fibreglass identified during mechanical tests, and their proper evaluation during the design elements.
Tests were carried out in accordance with the Republic of Lithuania and the EU standards (LST EN ISO 527-4, plastics):
- Determination of tensile properties (LST EN ISO 14126, fiber reinforced plastic composites);
- Determination of compressive properties in the plane direction (LST EN ISO 14125+AC, fiber-reinforced plastic composites);
- Determination of flexural properties (LST EN ISO 179-1: 2010, plastics);
- Determination of impact bending properties (Charpy method).