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KrosFlo® KR2i TFF System

A proven turnkey benchtop system for lab-scale process development, the KrosFlo® KR2i Tangential Flow Filtration (TFF) System is fully integrated and easy to use with walkaway automation.
       •  2ml - 15L volume
       •  13 cm2 - 5000 cm2 filtration area

TFF for lab-scale process Development

Designed for low volume, high concentration applications, the KrosFlo® KR2i TFF System from Repligen is designed for robust downstream ultrafiltration and microfiltration during purification and formulation development.

The KrosFlo® KR2i enables faster process development facilitating multiple tests/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 with volumes from 2mL to 15L, and filtration areas from 13 cm2 to 5000 cm2.


The fully integrated KrosFlo® KR2i TFF System features a digital peristaltic pump, graphical LCD display, digital pressure monitor, KR2i Pump head, automatic backpressure valve, filter module stand, and KF Comm real-time data collection software. Highly configurable and versatile, the KrosFlo® KR2i utilizes a number user-defined set-points to run complex application processes with numerous built-in safety alarms and stops. The system can run up to two stackable pump heads for higher flow rates.

KrosFlo® KR2i System
with Hollow Fiber Filters

2ml - 10L volume
13 cm2 - 3700 cm2 filtration area

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NEW! KrosFlo® FS Systems
with Flat Sheet Cassettes

140 ml - 15 L volume
0.1 - 0.3 m2 filtration area

KrosFlo® FS Systems

Fully integrated

Includes filters, pumps, process monitors, software and graphic display


ProConnex® custom flow paths, 4 filter module configurations, 4 membrane chemistries, 3 effective filter lengths


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


Use with hollow fiber filters or flat sheet cassettes

Ready to use

Out of the box functionality, short time to system proficiency

KONDUiT walkaway automation

KONDUiT add-on module for automated process value indication for conductivity, UV and temperature


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.

Walkaway TFF Automation

KrosFlo® KR2i with KONDUiT

Perform efficient, automated downstream tangential flow filtration with volumes from 2mL to 10L. Fully integrated and easy to use out of the box, the KrosFlo® KR2i TFF System delivers precise and reproducible control and documentation of tangential flow filtration processes.

Automatic Back pressure Control Valve

Unique to Repligen, the KrosFlo® Back Pressure Control Valve is key to integrating and automating the TFF process, reducing operator process management time and TFF processing time.

  • Automatically adjusts tubing pinch distance according to user-defined set-points for inlet, retentate, permeate or transmembrane pressures (TMP) when attached to the ProConnex® flow path
  • Maintains a uniform TMP throughout the process run, decreasing membrane fouling
  • Controls the permeate pressure and flow during microfiltration applications
  • Releases and tightens the pinch valve as solution viscosity increases or decreases during a process
  • Can be set to start pinching from the open, middle, or closed position
  • Compatible with tubing sizes 13, 14, 16, 25, HP15, 17, HP24, 18, HP35, 36, and HP36


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


KF Comm 2 Software, backward compatible with legacy KrosFlo® KR2i and KrosFlo® KMPi Systems, is conveniently installed on any computer using the Windows Operating System. The software is comptaible with Chrome, Mozilla, Firefox and Microsoft Explorer browsers and is always current with automatic software and firmware updates. 

  • Proprietary software optimized for KrosFlo® TFF Systems
  • Validated for GMP Processes with optional 21 CFR Part 11 option
  • Intuitive workflow with 13 modes of operation

KF Comm 2 Software

Compatible hollow fiber Filter Modules

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


MicroKros.png Process characterization,
Small-volume TFF in a laboratory
1-100 ml MLL FLL 1 x FL
2 x FL
3 x FL
13 – 20 cm2
26 - 59 cm2
41 - 92 cm2


MidiKros.png Process development at small scale 100 ml - 3 L FLL FLL 1 x FL
2 x FL
3 x FL
75 – 190 cm2
155 - 390 cm2
245 - 610 cm2

MidiKros TC

MidiKros-TC.png Process development at pilot scale 100 ml - 3 L 1/2" TC FLL 1 x FL
2 x FL
3 x FL
75 – 190 cm2
155 - 390 cm2
245 - 610 cm2

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

KONDUiT Add-on Monitor

Monitor and evaluate conductivity, UV and temperature for automated process controls. KONDUiT is an add-on module ready to use with the KrosFlo® KR2i and KMPi TFF Systems, with the ability to scale from 2mL to 500L process volumes.

KONDUiT adds:

  • End point conductivity control for UF /DF
  • End point UV control for diafiltering free drug from drug delivery particles
  • End point UV control for concentration of certain molecules
  • UV alarm for membrane breakthrough
  • A260 and A280 light sources available

*UV components sold separately



Conductivity Range 0.1 to 100 mS/cm
Temperature Range 0-70°
Pressure Range up to 75 psi (5 bar)
Dimensions (L x W x H): 7¾" x 4¾" x 4½" 
Weight 1.6 kg 

Scalable from lab-scale to process-scale

The KrosFlo® family of TFF Systems for concentration and diafiltration supports scale up from process development to commercial manufacturing.

Systems, Components and accessories

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  • IP 33 Enclosure
  • 600 RPM pump with reversible drive
  • 90-260 Vrms @ 50/60 Hz
  • Standard Easy Load 3 Pump Head for precision tubing L/S number 13, 14, 16, 25, 17, and 18 provided.
  • (Optional) Easy Load 3 pump head for high performance tubing L/S numbers 15, 24, 35, 36
  • ETL listed and CE/UL/cUL marked
  • Pump Drive Dimensions: 10.5 in x 8 in x 8 in


  • Measures and displays 4 pressures: Feed Pressure, Retentate Pressure, Permeate Pressure, Transmembrane Pressure (TMP)
  • User-defined pressure alarms and stop set-points
  • Available with different connector types (Luer and TC)  and selected materials of construction (PS, PC)


Maintain user-defined feed weight set-points, and total permeate mass during TFF processes.

KrosFlo® KR Jr Auxiliary Pump

Auxiliary pumps automatically increase or decrease buffer/product addition to feed reservoir.


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