A method of high pressure, high shear processing of a fluid, the method comprising the steps of: providing at least one isolator (24, 52) for selectively containing and discharging a second fluid, the at least one isolator further including an isolator wall (81, 91) defining a chamber (89, 99), a separator (22, 50) positioned in the chamber and movable between a first end of the chamber and a second end of the chamber, the separator engaging the isolator wall (81, 91) to further divide the chamber into a first sub-chamber (26, 56) and a second sub-chamber (28, 58) that are in pressure communication with each other but are not in fluid communication with each other, a first sub-chamber inlet valve (10, 43) in fluid communication with an ultrahigh pressure pump and the first sub-chamber (26, 56), a first sub-chamber outlet valve (12, 42) in fluid communication with the first sub-chamber (26, 56), a first check valve (16, 48) in fluid communication with the second sub-chamber (28, 58) to allow fluid to enter the second sub-chamber (28, 58), and a second check valve (14, 44) in fluid communication with the second sub-chamber (28, 58) to exhaust fluid from the second sub-chamber (28, 58); providing a processing unit in fluid communication with the second check valve (14, 44) of the at least one isolator (24, 52); alternately directing a first fluid at a pressure of at least 1.38 × 10 8 Pa (20,000 psi) into the first sub-chamber (26, 56) and directing the second fluid into the second sub-chamber (28, 58), wherein directing the first fluid into the first sub-chamber (26, 56) causes the second fluid to be discharged from the second sub-chamber (28, 58), through the second check valve (14, 44), and through the processing unit; and collecting the second fluid after it has passed through the processing unit. providing at least one isolator (24, 52) for selectively containing and discharging a second fluid, the at least one isolator further including an isolator wall (81, 91) defining a chamber (89, 99), a separator (22, 50) positioned in the chamber and movable between a first end of the chamber and a second end of the chamber, the separator engaging the isolator wall (81, 91) to further divide the chamber into a first sub-chamber (26, 56) and a second sub-chamber (28, 58) that are in pressure communication with each other but are not in fluid communication with each other, a first sub-chamber inlet valve (10, 43) in fluid communication with an ultrahigh pressure pump and the first sub-chamber (26, 56), a first sub-chamber outlet valve (12, 42) in fluid communication with the first sub-chamber (26, 56), a first check valve (16, 48) in fluid communication with the second sub-chamber (28, 58) to allow fluid to enter the second sub-chamber (28, 58), and a second check valve (14, 44) in fluid communication with the second sub-chamber (28, 58) to exhaust fluid from the second sub-chamber (28, 58); an isolator wall (81, 91) defining a chamber (89, 99), a separator (22, 50) positioned in the chamber and movable between a first end of the chamber and a second end of the chamber, the separator engaging the isolator wall (81, 91) to further divide the chamber into a first sub-chamber (26, 56) and a second sub-chamber (28, 58) that are in pressure communication with each other but are not in fluid communication with each other, a first sub-chamber inlet valve (10, 43) in fluid communication with an ultrahigh pressure pump and the first sub-chamber (26, 56), a first sub-chamber outlet valve (12, 42) in fluid communication with the first sub-chamber (26, 56), a first check valve (16, 48) in fluid communication with the second sub-chamber (28, 58) to allow fluid to enter the second sub-chamber (28, 58), and a second check valve (14, 44) in fluid communication with the second sub-chamber (28, 58) to exhaust fluid from the second sub-chamber (28, 58); providing a processing unit in fluid communication with the second check valve (14, 44) of the at least one isolator (24, 52); alternately directing a first fluid at a pressure of at least 1.38 × 10 8 Pa (20,000 psi) into the first sub-chamber (26, 56) and directing the second fluid into the second sub-chamber (28, 58), wherein directing the first fluid into the first sub-chamber (26, 56) causes the second fluid to be discharged from the second sub-chamber (28, 58), through the second check valve (14, 44), and through the processing unit; and collecting the second fluid after it has passed through the processing unit.