Auxilliary reservoir for a liquid system

Abstract

A liquid system for circulating a liquid through a circulation loop includes a liquid pump, a primary liquid reservoir and an auxiliary liquid reservoir. The liquid pump pressurizes liquid within the circulation loop. The primary liquid reservoir has a primary variable volume expandable to accommodate volumetric expansion of pressurized liquid up to a threshold volume. The auxiliary liquid reservoir has an auxiliary variable volume expandable only after the threshold volume is exceeded up to a maximum volume.

1 . A liquid system for circulating a liquid through a circulation loop, the liquid system comprising:
 a liquid pump for pressurizing liquid within the circulation loop to circulate the pressurized liquid through the circulation loop so that the pressurized liquid transfers heat to and from locations along the circulation loop, the pressurized liquid within the circulation loop having a volume that varies due to thermal expansion from an initial volume to a threshold volume, and from the threshold volume to a maximum volume;   a primary liquid reservoir in fluid communication with the circulation loop and having a primary variable volume expandable in response to volumetric expansion of the pressurized liquid due to thermal expansion up to the threshold volume; and   an auxiliary liquid reservoir in fluid communication with the circulation loop and having an auxiliary variable volume expandable in response to volumetric expansion of the pressurized liquid due to thermal expansion only after the threshold volume of the pressurized liquid is exceeded and expandable up to the maximum volume;   wherein the liquid fills the liquid system, and air is omitted from the liquid system.   
     
     
         2 . The liquid system of  claim 1  wherein the primary variable volume accommodates volumetric expansion of the liquid across operating pressures of the liquid pump up to a threshold pressure. 
     
     
         3 . The liquid system of  claim 2  wherein the auxiliary variable volume accommodates volumetric expansion of the liquid above the threshold pressure up to a maximum pressure. 
     
     
         4 . The liquid system of  claim 3  and further comprising:
 a relief valve connected to the circulation loop and configured to open above the maximum pressure. 
 
     
     
         5 . The liquid system of  claim 3  wherein the auxiliary liquid reservoir comprises a spring-charged bellows having a spring with a spring force that yields above the threshold pressure. 
     
     
         6 . The liquid system of  claim 5  wherein the primary liquid reservoir comprises a bootstrap reservoir. 
     
     
         7 . The liquid system of  claim 6  wherein the liquid pump and the primary liquid reservoir are packaged in a common housing and the auxiliary liquid reservoir is packaged in a separate housing. 
     
     
         8 . The liquid system of  claim 6  wherein the primary liquid reservoir includes a level sensor for determining a volume of fluid within the primary liquid reservoir. 
     
     
         9 . The liquid system of  claim 1  and further comprising:
 a liquid load connected to the liquid pump through the circulation loop; 
 wherein the liquid load imparts a thermal input to the pressurized liquid. 
 
     
     
         10 . A liquid system comprising:
 a circulation loop;   a liquid pump configured to pressurize liquid within the circulation loop wherein the liquid fills and circulates through the circulation loop to transfer heat to and from locations along the circulation loop, and air is omitted from the circulation loop;   a primary reservoir in fluid communication with the circulation loop and configured to expand in volume in response to volumetric expansion of the liquid due to thermal expansion under pressure within the circulation loop up to a threshold pressure; and   an auxiliary reservoir in fluid communication with the circulation loop and configured to expand in volume in response to volumetric expansion of the liquid due to thermal expansion only after the threshold pressure is exceeded;   wherein activations of the primary reservoir and the auxiliary reservoir in response to volumetric expansion of the liquid due to thermal expansion are staged such that utilization of volumetric capacity of the auxiliary reservoir occurs only after volumetric capacity of the primary reservoir is maxed out.   
     
     
         11 . The liquid system of  claim 10  and further comprising:
 a liquid load connected to the liquid pump through the circulation loop; 
 wherein the liquid load imparts a thermal input to the liquid. 
 
     
     
         12 . The liquid system of  claim 11  wherein the auxiliary reservoir comprises a spring charged bellows having a spring with a spring force that yields above the threshold pressure. 
     
     
         13 . The liquid system of  claim 12  wherein the primary reservoir comprises a bootstrap reservoir integrated into a housing of the fluid pump, and the auxiliary reservoir is packaged in a separate housing. 
     
     
         14 . The liquid system of  claim 12  wherein the primary reservoir includes a level sensor for determining a volume of fluid within the primary reservoir. 
     
     
         15 . The liquid system of  claim 10  wherein the auxiliary reservoir expands to a maximum volume after the primary reservoir expands to a threshold volume. 
     
     
         16 . A method of accommodating expanding liquid in a closed fluid circulation loop, the method comprising:
 circulating pressurized liquid in a closed fluid circulation loop using a pump, wherein the liquid transfers heat to and from locations along the closed fluid circulation loop, and wherein the pressurized liquid fills the closed fluid circulation loop and air is omitted from the closed fluid circulation loop;   expanding a volume of a primary reservoir connected to the closed fluid circulation loop up to a threshold volume in response to thermal expansion of the pressurized liquid to a threshold level; and   sequentially expanding a volume of an auxiliary reservoir connected to the closed fluid circulation loop up to a maximum volume in response to thermal expansion of the pressurized fluid from the threshold level to a maximum level.   
     
     
         17 . The method of  claim 16  wherein the volume of the primary reservoir is expanded to a threshold pressure and the volume of the auxiliary reservoir is expended after the threshold pressure is reached. 
     
     
         18 . The method of  claim 17  wherein the step of expanding the volume of the primary reservoir comprises expanding a bootstrap reservoir integrated with the pump. 
     
     
         19 . The method of  claim 18  wherein the step of expanding the volume of the auxiliary reservoir comprises expanding a bellows-type reservoir having a spring that yields at the threshold pressure.