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KrosFlo® KML TFF System

The KrosFlo® KML System is designed for upstream bioreactor perfusion using tangential flow filtration (TFF), with a single-use, non-pulsating, levitating magnetic pump.
     • 1.5L - 100L volume

Featuring a low shear magnetic levitating pump for improved cell viability, the KrosFlo® KML TFF System is ideal for upstream perfusion managing 1.5L to 100L working volume bioreactors.  Combined with gamma sterilized single-use ProConnex® Flow Paths, the KrosFlo® KML System delivers high protein production during lengthy TFF perfusion operations.

The KrosFlo® KML System enables faster process development facilitating multiple tests and processes, accurate process definition and execution consistency. Fully integrated and ready to use out of the box, the system includes precise and reproducible control and documentation of TFF processes.


The KrosFlo® KML TFF System is a completely integrated system with a color touchscreen to display key parameters. There are visual and audible alarms with safety interlocks to ensure process parameters are maintained. The system comes with two auxiliary peristaltic pumps, two auxiliary scales for precise the management of the flow dynamics are sold separately. A retentate control valve manages TMP by adjusting the pinch distance between the plunger and the tubing, and an ultrasonic retentate flow meter that clamps on the tubing. To prevent cells from settling and forming a gel layer on the membrane lumen, the KrosFlo® KML System adjusts through a PID control loop from the flow meter. Further advancements include automatic back pulsing features and USB port for real time data collection.

Fully integrated

Includes filters, pumps, scales, process monitors, flow meters, software and graphic display


Multiple modes

TFF Perfusion, 5 additional TFF modes, 1 manual mode. Scale sizes selected by the user


2 filter module configurations, 4 membrane chemistries, 3 effective filter lengths

easy User controls

Pressures, flows, weights and process overview with end user set-point functionality. 

Ready to use

Out of the box functionality, short time to system proficiency


Compatible with KrosFlo® TFF perfusion systems from process development to commercial manufacturing


Repligen develops and manufactures products for the biopharmaceutical industry under an ISO 9001 quality management system. We focus on the timely delivery of high quality, consistent and robust products, to ensure business continuity for our customers.

about Repligen Manufacturing


Enhanced through an engineering design process, ProConnex® Flow Paths are customized, configurable and complete assemblies for tangential flow filtration.  Designed for use with hollow fiber and/or flat sheet TFF systems, the assemblies are sterile, fit for upstream or downstream processing and manufactured in compliance with ISO guidelines in an ISO 7 clean room.

ProConnex® Flow Paths

Automated Process Control Modes

Perfusion mode, five system process control modes and one manual operation mode are available with the KrosFlo® KML TFF System.

Mode Primary Application  
  Perfusion Mode Cell Culture perfusion  
  Manual Mode Simple concentration of the process solution  
C Concentration Mode 

Simple concentration of the process solution
Automated flushing of the hollow fiber filter

C/D Concentration / Diafiltration Concentration and then diafiltration of the process solution in succession  
C/D/C Concentration / Diafiltration / Concentration Diafiltration of the process solution with one buffer before concentration of the process solution a second time  
C/D/D/C Concentration / Diafiltration / Diafiltration / Concentration Diafiltration of the process solution with two different buffers in succession before concentration of the process solution a second time  
CFC Constant Feed Concentration Concentration of the solution while maintaining a constant feed weight  

Compatible Filter Modules

Volume Inlet/ Outlet Side
Effective Length (cm) Total
Length (cm)

MiniKros Sampler

MiniKros-Sampler.png Batch TFF of small volumes 3 L -15 L 0.75" TC 0.75" TC 1 x FL
2 x FL
3 x FL
490 – 1000 cm2
1000 - 2200 cm2
1600 - 3400 cm2


MiniKros.png Pilot-scale TFF 5 L - 50 L 1.5" TC 0.75" TC 1 x FL
2 x FL
3 x FL
0.16 - 0.31 m2
0.32 - 0.65 m2
0.51 - 1.0 m2

See Hollow Fiber Membrane Types

Scalable from benchtop to production

The KrosFlo® family of TFF Systems for perfusion cell culture supports scale up from process development to commercial manufacturing.


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  • Flow Range 350 ml/min to 13 LPM at 7000 RPM @ 15 psig (1 bar)
  • 0-9000 RPM range with 300 watt power supply
  • FDA approved materials, USP Class VI, Animal BSE/TSE Free Material
  • PLC with color 8.4" touchscreen HMI
  • 0-40° C Operating Range
  • CE/UL/cUL marked
  • Automation Direct DL06 PLC with 800x600 Resolution HMI
  • Splash-proof

Integrated Detachable
Pro-Connex® Flow Path Stand

Designed to hold gamma sterilized single-use Pro-Connex® Flow Path assemblies

2 Integrated Peristaltic Pumps

  • Flow ranges from 0.16 to 347 ml/min
  • Permeate pump sequenced for back-pulsing in the Perfusion mode
  • RS232 communication
  • Integrated power within single connection to KML

Retentate Control Valve

  • Non-invasive to process stream
  • 4-20 mA control

Ultrasonic Single Pass Retentate Flow Meter

  • Measures flow up to 20LPM +/- 5%
  • Calibrated for Dow Pharma tubing at 35°C


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