Dirt and air separatorfrom ArmstrongArmstrong has added its DAS dirt& air separator to the Air andExpansion Control Line.

The separator is designed toeliminate entrained air andseparate dirt particles associatedwith the start-up andmaintenance of hydronic systemsand uses a robust stainless steelcoalescing medium, which directsdirt particles of all sizes tocollect in the chamber at thebottom of the unit. It also allowsthe removal of micro-bubblesand entrained air through the airvent located at the top.

The new DAS from Armstrong ismanufactured to ASME code,and the company claims that it isone of the first products with awelded head that also providesASME certification as a standardfeature in the Separator productclass.

Products for hazardous environmentsNeptune Chemical Pump Co.,Inc. has expanded its range ofseries 500 ‘dia-PUMPs’ withexplosion-proof motors andNEMA 7 stroke positioners foruse in hazardous environments.

Neptune dia-PUMPs areh y d r a u l i c a l l y - a c t u a t e ddiaphragm pumps that provideleak-free metering of a widevariety of corrosive, flammableor hazardous liquids.

The explosion-proof model isaimed for use in oil-and-gas, CPI,and a wide variety of otherextreme environments.

The Series 500 features checkvalves that are removable forinspection or cleaning withoutdisconnecting piping. Withcapacities from 0.03 gph to 80gph simplex and 160 gph duplex,the pumps can handlepressures up to 3,000 psi. TheSeries 500 pumps have the abilityto adjusted by micrometer dial,while running, through 100% oftheir operating range.

The pumps also also featureNepture’s variable oil by-pass™stroke adjustment, which canimprove valve performance overvariable linkage designs. Thepump’s liquid end can beconstructed of 316SS, Alloy 20,PVC or Kynar.

Neptune’s range of explosion-proof motors and stroke positioners for use inhazardous environments.

Rotary Power, based inNewcastle-upon-Tyne, UK is nowsupplying the A range opencircuit and C range chemicalmetering axial piston pumps, fullycertified to comply with the ATEXDirective 94/9/EC.

The pumps are suitable forGroup II, Zone 1 hazardousenvironment applications, thecompany says.

The A range axial piston opencircuit pumps and motors whichare available in displacementsfrom 11.5 cc to 125 cc/rev aredesigned for heavy-dutyapplications. The constructionallows operation on a wide rangeof fluids including mineral oils,water emulsions, water glycolsand phosphate esters, RotaryPower claims, making it suitablefor diverse and arduousapplications such as subsea andoffshore.

The C range pumps are suitablefor all types of polyol blends andisocyanates used in thepolyurethane foam market.

www.worldpumps.com WORLD PUMPS September 20056

n e w s p r o d u c t a n d s e r v i c e s

ATEX certification forrotary power pumps

Concentric Pumps Ltd haspatented a new design of sealshroud to combat the problem ofleaking seals and consequentbearing failure in automotivewater pumps, the company says.

The new Concentric designincorporates a shroud, normallyof pressed steel, inserted into thepump housing to form a pressurechamber around the seal. Thisprovides a better, more stableenvironment for the seal,dramatically reducing silicateformation and consequently therisk of failure. It also reduces the

cost of both housing and seal,Concentric says. The uniquefeature of the Concentric patentis the number of aperturesaround the periphery of theshroud which allow relatively highpump outlet pressure within thechamber. The space between theshroud and the pump shaft isdesigned to ensure evendistribution of the coolant flowover the seal, while maintainingpressure.

The new design is the first toaddress the problem of localixedboiling of the coolant at the

sealing faces, the companyclaims. Boiling leads to theformation of silicates which canprogressively degrade the sealfaces, but it can be avoided byraising the pressure around theseal and hence the boiling pointof the coolant. At 6000 rpm theConcentric shroud will increasecoolant boiling point by around25°C.

The high pressure achieved by theshroud also helps to avoid theproblem of dry running whichcan occur when low pressurescause the coolant to vaporize,Concentric reports. The resultinghigh temperature leads to‘thermal rotation’ or distortion ofthe primary sealing ring, againencouraging silicates to form anabrasive film on the seal faces.

In addition to its technicaladvantages, the Concentricshroud is suitable for volumemanufacturing and will allow theuse of a less expensive seal. It canalso form the pump locationdiameter, so reducing the cost ofmanufacturing the housing andoff-setting the on-cost of theshroud itself.

Concentric Pumps’ new seal shroud which forms a pressure chamber aroundwater pump seals.

New water pump shroud can reduce failures