Close-Coupled pumps brochure

Close-Coupled pumps brochure

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Watson-Marlow 521VI/RELC, 521I/RELC, 521F/RELC, 521FX/RELC: 0-2 bar IP55 pumps fitted with LoadSure low-pressure element pumpheads

521 close coupled pumps offer IP55 ingress protection for light industrial environments. They offer rugged, industrial pumping, with all the pumphead features of cased drives, but at the lowest whole-life cost.

520REL low-pressure LoadSure element pumphead features large swept volume with sprung rollers for high accuracy

Chemically-resistant polyphenylene sulphide track and rotor, and stainless steel rollers and bearings

Low rotational speeds greatly increase tube life and system reliability

Clutched rotor for rapid, effortless tube loading

Rugged, tool-unlockable guard

521VI varmeca521VI Varmeca close coupled drives bring 10:1 speed control, constant torque output and total reliability to the industrial environment. The drive offers 230V and 400V three-phase power options, plus 110V and 230V single-phase. Control is by a large speed knob and forward/reverse switching.

Varmeca integral inverter offering 10:1 control ratio: 63 rpm, 220 rpm and 275 rpm maximum speeds

Stop/forward/reverse control and analogue or digital remote control. There is a PROFIBUS option


521F close coupled pump521F Fixed speed drives are three-phase powered

There is a choice of speeds: 60 rpm, 213 rpm and 291 rpm

Flow rates from 2.5 ml/min to 4,600 ml/min

Other speeds are available on request


521FX Duplex fixed speed521FX Duplex fixed speed drives have twin pumpheads allowing two channel pumping.

There is a choice of speeds: 55 rpm and 183 rpm

Flow rates to 860 ml/min from each channel

Twin 520R2C pumpheads for balanced flow in two channels


521F/REMC521I Inverter-controlled, variable speed drives include a stand-alone Siemens inverter to control pump speed.

Inverter can be mounted beside the pump or remotely

Three speed ranges: 6-60 rpm; 21-213 rpm; 29-291 rpm

Flow rates to 4,600ml/min


  521F 521V 521P
Industry approved motors with 2 standard gearing speeds
Supplied with free standing variable frequency drive (VFD)  
Speed start/stop forward/reverse keypad control with remote control features    
Speed control ratio   10:1 5:1
VFD input power 230/3/60, 460/3/60, 115/1/60 in either NEMA 1 or NEMA 4X    
Standard integral gearmotor 3 phase 230/460V 60Hz TEFC  
Optional 115/1/60    
Optional gearbox and NEMA C motor  
Optional explosion proof (XP) motor  
Four vane pneumatic motor with speed limiting    
Optional FDA approved white epoxy paint
Optional baseplate mounting


Close coupled drives offer rugged, industrial, quality pumping, with all the pumphead features of cased drives, but at the lowest possible whole-life ownership cost.

Datasheet download


Manual download

 521F/RELC, 521I/RELC, 521VI/RELC, 521FX/RELC

521 REL Closed Coupled


LoadSure® Element tubing flow rates, ml/min(gph)
Tube Material Speed 3.2mm 6.4mm 9.6mm

Pumpsil, Sta-Pure PFL, Neoprene
6-57rpm 10-105(0.2-1.7) 40-400(0.6-6.3) 90-905(1.4-14)
  23-227rpm 40-400(0.6-6.3) 155-1560(2.5-24.7) 360-3590(5.7-57)

Marprene TL, Bioprene TL
6-57rpm 10-95(0.2-1.5) 40-380(0.6-6.0) 85-865(1.3-14)
  23-227rpm 40-380(0.6-6.0) 155-1560(2.5-24.7) 345-3430(5.5-54)

Tubing and hoses for your industry

  • Contact Us

    To order this product please contact us on:

    Tel: +1 978 658 6168 and Toll free +1 800 282-8823

    You can also send us an email or find your nearest distributor