Sealless Magnetic CoupledMultistage Centrifugal Pumps

Type HZM / HZMR / HZMB

ourcontribu

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protection

Containment shell protection

The clearances between drive rotor and motorsupport lantern respectively between bearingbracket and containment shell are arranged suchthat rubbing of the magnets on the containmentshell will be avoided, even in the case of wornout ball bearings.

Magnetic coupling

The single elements of the multipolar magneticcoupling are manufactured of permanent magnetmaterial "Cobalt Samarium" with unlimited life-time. The magnets in the driven rotor are com-pletely encapsulated, not in contact with liquid.Power is transmitted to the hermetically sealedliquid end by a bank of external magnets. Innerand outer magnet rings are locked together bymagnetic forces and work as a synchronouscoupling. The inner magnet ring transmits therequired torque direct to the impeller. Overload ofthe magnetic coupling and slipping will not causedemagnetization if temperature monitoring isavailable. The magnetic drives are designed forelectric motors, direct on line starting. Should asubsequent increase of motor power be required,i.e. when installing larger impellers, the nominalpower of coupling can be increased with additio-nal magnets.

The maximum drive power of HZM / HZMR-pumps is approximately 220 kW @ 2900 rpm(350 HP @ 3500 rpm).

General

DICKOW-pumps of series HZM are seallessmultistage horizontal centrifugal pumps, drivenby a synchronous permanent magnetic coupling.The static containment shell forms a closedsystem with hermetically sealed liquid end.

Application

Magnetic driven HZM-pumps are designed toimprove plant and personnel safety, especiallywhen handling toxic, explosive or other dange-rous liquids which react on contact with theatmosphere. For all these services the contain-ment shell replaces the double acting mechanicalseal with external fluid reservoirs and the neces-sary control equipment. HZM-pumps thereforeoffer exceptional benefits to the chemical, petro-chemical and allied industries, and protect theenvironment.

Max. capacity and differential head:

50 Hz - appr. 500 m3/h and appr. 380 m60 Hz - appr. 500 m3/h and appr. 460 m

(appr. 2200 gpm and 1500 ft)

The maximum operating temperature is 200°C.

Hazardous area

Together with the required Ex-drive motors, theHZM-pumps can be applied in hazardous areaGroup II, Category 2. The pumps meet the basicsafety and health requirements of Explosion-proof Directive 94/9 EC and are suitable forplants with increased safety requirement.

For close coupled pumps (HZMB) the contain-ment shell temperature is limited when usingex-motors. The values are available on request.

Design / Casing

HZM-pumps are multistage between bearingsring section pumps with closed impeller, endsuction and top discharge flange. Suction anddischarge casing are provided with sturdy feetfor mounting on base plate.

Containment shell

The containment shell is designed as a pressuri-zed vessel to separate the pumpage from theatmosphere.

The containment shell is not used as an additio-nal bearing holder. No dynamic stress occurs.

The containment shell is bolted to the bearinghousing in a manner that allows removal of thebearing bracket (HZM-pumps) respectively of thedrive motor (HZMB-pumps) together with thedrive rotor without draining the pump.

safety ring

containment shell

bearing bracket

S4 = 0,5 mm S1 = 1,0 mm

magnetic fied

drive rotor

drive magnetscontainment shell

driven rotor

adhesive

adhesive

Impellers, NPSH-values

When operating hermetically sealed pumps, cavi-tation must be avoided by all means. This appliesespecially for handling hydrocarbons, condensa-tes and other low boiling liquids.

For lowest NPSH-values, the impeller of the firststage is designed as a suction impeller withenlarged eye.

Balanced thrust loads

The thrust loads of the closed impellers arebalanced by throttle gap and relief holes.The balancing of residual loads is effected bythe balancing disc on pressure side.

The front side of the balancing disc is pressuri-zed by the pump pressure p1. The rear disc side

is connected with the pressure side of the firstpump stage via an external pipe. According tothe rotor position and the adjusting gap S, acounter force is created by the differential pres-sure between front and rear side of the balancingdisc. This counter force acts against the residualload towards the containment shell such that nothrust loads occur. No thrust bearings are requi-red. The start-up rings keep the pump shaft inposition during start-up and shut-off.

Monitoring

Connection for temperature detection element forcontainment shell surface temperature is availa-ble as standard. Dry running protection andmonitoring of ball bearings and containment shelltemperature with the patented "mag-safe" systemis highly recommended.

Double sleeve bearings

The pump shaft is carried by wetted sleevebearings. Standard material is pure SiliconCarbide with diamond layer, providing limiteddry-run capability. SiC is highly resistant tocorrosion and wear and can be used for all kindof liquids, also for solid containing products.The SiC-components are shrinkfitted or elasti-cally beared by tolerance rings and thereforeprotected against shock and thermal stress.

Internal cooling flow

When the pump is in operation, eddy currentsare developed inside the metallic containmentshells and converted into heat in the magnetarea.

In order to avoid inadmissible temperature rise ofthe pumped fluid, this heat is dissipated throughan internal cooling flow.

Outer ball bearings

The drive shaft of the HZM-pumps is carried bygenerously dimensioned antifriction bearings,grease filled for lifetime and protected against theatmosphere by a lip seal.

The drive rotor of HZMB-pumps is mounted onthe motor shaft. That means, additional bearings,elastic coupling and coupling alignment are notrequired.

The drive shaft of HZMR-pumps is carried bygenerously dimensioned oil lubricated antifrictionbearings. The bearings are rated for 25000operating hours. The oil bath is protected againstthe atmosphere by a contactless labyrinth seal.Oil level is controlled by constant level oiler. Theoil chamber is sealed from the magnet chamberalso by labyrinth seal.

p2 < p1

stationary

balancing disc, rotatingand floating with rotor

circulation channelintermediate flange

containmentshell

HZM-Design containment shell protection

internal magnets external magnets

containmentshell

bearing bracket

diffuser

grease lubricatedball bearings

sleeve bearing,discharge side

discharge casingstage casing

suction casing

sleeve bearing,suction side

closed impeller

Optional designsType HZMR – with oil lubricated bearing bracket

mag

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oil b

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bear

ing

brac

ket

Type HZMB – close coupled design

mag

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mot

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Issu

e 12

.11

Technical changes reserved. Printed in Germany. 100-02.12 S&W

DICKOW PUMPEN KGPostfach 125484465 Waldkraiburg · GermanyTel. ++ 49 86 38 6 02 0Fax ++ 49 86 38 6 02 200 + 6 02 201info@dickow.de / export@dickow.dewww.dickow.de

Performance range

Performance curves for the individual pump sizes,also for 1750 / 3500 rpm, with NPSH-valuesand power consumption, are available onrequest.