Dual-circuit series counterflow chiller with intermediate waterbox

Abstract

A dual refrigeration circuit watercooled chiller has its respective evaporators and condensers interconnected by waterboxes such that the first circuit tubes discharge into the respective waterbox and the flow of water then passes from the respective waterboxes to the respective evaporator/condenser tubes of the second circuit. Instrumentation is attached to the waterboxes to enable the measurement of the leaving temperature differential to provide improved control. Since the first and second circuit tubes are separate and independent, both serviceability and flexibility in design are substantially enhanced.

1 . A chiller system of the type having first and second refrigeration circuits with each refrigeration circuit having a compressor, a condenser, an expansion device and an evaporator and with the respective evaporators in the first and second circuits having a plurality of tubes to conduct the flow of fluid to be cooled, and with the respective evaporators of the first and second circuits being interconnected in series relationship such that the fluid to be chilled passes serially through the respective evaporators of the first and second, circuits, comprising:
 a waterbox interconnected between the evaporators of the first and second circuits and having a unitary reservoir for conducting the flow of fluid from the tubes in the evaporator of the first circuit and to the tubes of the evaporator of the second circuit.   
   
   
       2 . A chiller system as set forth in  claim 1  wherein each of said first and second evaporators includes an intermediate tubesheet, and wherein said intermediate waterbox is interconnected between said tubesheets. 
   
   
       3 . A chiller system as set forth in  claim 2  wherein said intermediate waterbox is cylindrical in form and is connected to said tubesheets at the respective circular ends of the cylinder. 
   
   
       4 . A chiller system as set forth in  claim 3  wherein said waterbox has a plurality of holes formed longitudinally between its opposite ends and further wherein bolts are passed through the tubesheets and through said holes. 
   
   
       5 . A chiller system as set forth in  claim 1  and including temperature measurement instrumentation connected to said waterbox to measure the temperature of the water therein. 
   
   
       6 . A chiller system as set forth in  claim 1  wherein the respective condensers of the first and second circuits are connected in series and are watercooled and include a waterbox interconnected between the condensers. 
   
   
       7 . A chiller system as set forth in  claim 6  wherein said evaporators of first and second circuit are adapted to conduct the flow of cooling water in counterflow relationship to the flow of cooling water in the condensers of the first and second circuits. 
   
   
       8 . A dual-circuit chiller, comprising:
 a first circuit having a compressor, a condenser, an expansion device and an evaporator, with the evaporator having a plurality of tubes for conducting the flow of water to be cooled from an inlet end to an outlet end of the tube;   a second circuit having a compressor, a condenser, an expansion device and an evaporator with the evaporator having a plurality of tubes for conducting the flow of water to be cooled from an inlet end to an outlet end of the tubes; and   an evaporator waterbox fluidly interconnected between said first circuit tube outlet ends and the second circuit tube inlet ends, such that water to be cooled flows from said first circuit tube outlet ends, into said evaporator waterbox and then into the second circuit tube inlet ends.   
   
   
       9 . A dual-circuit chiller as set forth in  claim 8  and including a first intermediate tubesheet surrounding said first circuit tube outlet ends and a second intermediate tubesheet surrounding said second circuit tube inlet ends and further wherein said waterbox is connected to said first and second intermediate tubesheets. 
   
   
       10 . A dual-circuit chiller as set forth in  claim 9  wherein said waterbox is cylindrical in form. 
   
   
       11 . A dual-circuit chiller as set forth in  claim 10  wherein said cylinder has holes formed longitudinally between its end surfaces and further wherein bolts pass through said first and second intermediate tubesheets and through said holes to secure the waterbox to said first and second intermediate tubesheets, respectively. 
   
   
       12 . A dual-circuit chiller as set forth in  claim 8  and including temperature measurement instrumentation attached to said waterbox for measuring the temperature of the water therein. 
   
   
       13 . A dual-circuit chiller as set forth in  claim 8  wherein said condensers of said first and second circuits are watercooled and are connected in serial flow relationship and further include a condenser waterbox interconnected between the condensers of said first and second circuits. 
   
   
       14 . A dual-circuit chiller as set forth in  claim 6  wherein the flow of water in said evaporators is in counterflow relationship with the flow of water in said condensers.