Direct solar steam generator and method of shuting down a direct solar steam generator

Abstract

A direct solar steam generator is provided. The direct solar steam generator includes a solar evaporator having an evaporator circuit for circulation of a working fluid, an evaporator inlet pipe for supplying fluid to the evaporator circuit and an evaporator outlet pipe for collecting the working fluid exiting the evaporator circuit, and a solar concentrator for concentrating solar energy towards the evaporator circuit. The direct solar steam generator also includes a fluid arrangement configured to allow forming a static liquid seal in the outlet pipe using the working fluid.

What is claimed is: 
     
         1 - 17 . (canceled) 
     
     
         18 . A direct solar steam generator comprising:
 a solar evaporator including an evaporator circuit for circulation of a working fluid, an evaporator inlet pipe for supplying fluid to the evaporator circuit, and an evaporator outlet pipe for collecting the working fluid exiting the evaporator circuit;   a solar concentrator for concentrating solar energy towards the evaporator circuit; and   a fluid arrangement configured to allow forming a static liquid seal in the outlet pipe using the working fluid.   
     
     
         19 . The direct solar steam generator as recited in  claim 18  wherein the fluid arrangement is configured for transferring the working fluid in liquid state into the outlet pipe to form a static liquid seal of the working fluid in the outlet pipe. 
     
     
         20 . The direct solar steam generator as recited in  claim 19  wherein the fluid arrangement includes at least one by-pass valve for controlling flow fluid transferred from the inlet pipe to the outlet pipe. 
     
     
         21 . The direct solar steam generator as recited in  claim 18  wherein the fluid arrangement is configured for transferring fluid from inlet pipe to outlet pipe with by-passing the evaporator circuit. 
     
     
         22 . The direct solar steam generator as recited in  claim 18  wherein the fluid arrangement includes a by-pass pipe connecting the fluid inlet pipe to the steam outlet pipe with by-passing the evaporator circuit. 
     
     
         23 . The direct solar steam generator as recited in  claim 22  further comprising at least one inlet valve for controlling fluid flow entering inlet pipe. 
     
     
         24 . The direct solar steam generator as recited in  claim 23  wherein the by-pass pipe connects the inlet pipe upstream of the at least one inlet valve. 
     
     
         25 . The direct solar steam generator as recited in  claim 22  further comprising at least one outlet valve for controlling fluid flow exiting outlet pipe. 
     
     
         26 . The direct solar steam generator as recited in  claim 25  wherein the fluid arrangement is configured for creating a static liquid seal upstream of the at least one outlet valve. 
     
     
         27 . The direct solar steam generator as recited in  claim 25  wherein the by-pass pipe connects the outlet pipe upstream the at least one outlet valve. 
     
     
         28 . The direct solar steam generator as recited in  claim 25  wherein the outlet pipe drops between the evaporator circuit and the at least one outlet valve. 
     
     
         29 . A solar power plant comprising at least one of the direct solar steam generator as recited in  claim 18 . 
     
     
         30 . A method of shutting down a direct solar steam generator comprising a solar evaporator including an evaporator circuit, an evaporator inlet pipe and an evaporator outlet pipe, and a solar concentrator for concentrating solar energy towards evaporator circuit, the method comprising:
 forming a static liquid seal in the outlet pipe during or after the shut down of the steam generator.   
     
     
         31 . The method as recited in  claim 30  wherein the forming the static liquid seal includes transferring working fluid in liquid state into the outlet pipe to form a static liquid seal of working fluid in the outlet pipe. 
     
     
         32 . The method as recited in  claim 30  wherein the forming the static liquid seal includes transferring fluid from the inlet pipe to the outlet pipe with by-passing the evaporator circuit. 
     
     
         33 . The method as recited in  claim 30  further comprising closing the inlet pipe and closing the outlet pipe. 
     
     
         34 . The method as recited in  claim 30  wherein fluid is transferred from upstream an inlet valve closing the inlet pipe to upstream an outlet valve closing the outlet pipe.