The hydrostatic test of large-diameter heat-transfer-fluid(HTF) pipe has always been a difficult point in parabolic trough solar thermal power plants

in which the blind plate is the most important weak link. For the large-diameter HTF pipe of the parabolic trough solar thermal power plants

using the conventional flat welded blind plate easily causes swelling and deformation of the blind plate

and weld cracking

leading to failure of the water pressure test and even safety problems. To solve this problem

the different calculation methods of hydrostatic test blind plate were studied and compared. Combined with the design of hydrostatic test blind plate in practical projects at home and abroad

a new method combing double-reinforcement-ring and radial strengthening rib was developed in this paper to improve the stiffness of blind plate

reduce the plate thickness and strengthen the welding. The results indicated that

the design of the integral butt welding blind plate with double-reinforcement-ring combined with radial strengthening rib not only improves the stiffness of the blind plate effectively

but also reduces the thickness of the blind plate from 70 mm to 27.3 mm

which is equivalent to 39% of the original thickness. For the hydrostatic test of large-diameter HTF pipe of parabolic trough solar thermal power plants

the optimized blind plate exhibited better applicability

and it was successfully applied to the construction process of foreign solar thermal power stations.