▁characteristics ▁of ▁a ▁half ▁co il ▁jack et ▁perm its ▁faster ▁disp lacement ▁of ▁the ▁heat ▁transfer ▁fluid ▁in ▁the ▁jack et ▁( typ ically ▁less ▁than ▁ 6 0 ▁seconds ). ▁This ▁is ▁des irable ▁for ▁good ▁temperature ▁control . ▁It ▁also ▁provides ▁good ▁distribution ▁of ▁heat ▁transfer ▁fluid ▁which ▁avoid s ▁the ▁problems ▁of ▁non ▁uniform ▁he ating ▁or ▁cool ing ▁between ▁the ▁side ▁walls ▁and ▁bottom ▁d ish . ▁Like ▁the ▁single ▁jack et ▁design ▁however ▁the ▁in let ▁heat ▁transfer ▁fluid ▁is ▁also ▁vulner able ▁to ▁large ▁oscill ations ▁( in ▁response ▁to ▁the ▁temperature ▁control ▁val ve ) ▁in ▁temperature . ▁ ▁Constant ▁flux ▁cool ing ▁jack et ▁ ▁The ▁constant ▁flux ▁cool ing ▁jack et ▁is ▁a ▁relatively ▁recent ▁development . ▁It ▁is ▁not ▁a ▁single ▁jack et ▁but ▁has ▁a ▁series ▁of ▁ 2 0 ▁or ▁more ▁small ▁jack et ▁elements . ▁The ▁temperature ▁control ▁val ve ▁oper ates ▁by ▁opening ▁and ▁closing ▁these ▁channels ▁as ▁required . ▁By ▁varying ▁the ▁heat ▁transfer ▁area ▁in ▁this ▁way , ▁the ▁process ▁temperature ▁can ▁be ▁reg ulated ▁without ▁alter ing ▁the ▁jack et ▁temperature . ▁ ▁The ▁constant ▁flux ▁jack et ▁has ▁very ▁fast ▁temperature ▁control ▁response ▁( typ ically ▁less ▁than ▁ 5 ▁seconds ) ▁due ▁to ▁the ▁short ▁length ▁of ▁the ▁flow ▁channels ▁and ▁high ▁velocity ▁of ▁the ▁heat ▁transfer ▁fluid . ▁Like ▁the ▁half ▁co il ▁jack et ▁the ▁he ating / co ol ing ▁flux ▁is ▁uniform . ▁Because ▁the ▁jack et ▁oper ates