Zenith Pumps H-Series Gear Pumps

1 Zenith PumpsH-SeriesGear PumpsInstallation,Care And MaintenanceZenithHigh-TemperatureGear PumpsHigh Volumetric EfficiencyMaximum efficiency is achieved with optimum operating clearances and assured under pressure by built-in alignment PulsationUnique design offers virtually pulselessflow without valves or flexible elements to hinder ConstructionGround and lapped components for close control of operating Pumps2 Thoroughly read and understand this entire manual before installation and operation of 1926, Zenith Pumps was approached by the synthetic fiber industry to design a pump to provide a precise, pulseless,repeatable flow and assure better qualitycontrol. The options then were the same as those in the chemical process industrytoday diaphragm, lobe, coarse gear , pis-ton, plunger and screw Pumps .

2 Each hadproblems with pulsation, flow inaccuracies,multiple seal areas and slip, which requiredconstant calibration, high maintenance andextended Pumps met the challenge anddesigned a rotary external gear pump ofunique precision and Type:Rotary external spur gear , single : Refer to pump Speed: 3-180 rpm depending upon application conditions and fluid : To 645 F (350 C),(950 F maximum with special fasteners and seals).Manufacturing techniques were devel-oped to hold tolerances to .00005", andan inter-nal pressure relief mechanismassured reliable precision metering. Thepump s simple design of only three mov-ing parts two metering gears and adrive shaft provided long life and easy years since, Engineers haverelied on Zenith to provide precision fluid handling solutions for their most difficult pumping applications.

3 Zenithgear Pumps can be found wherever precise, pulseless, repeatable meteringof fluids is AccuracyStable, repeatable flows are assuredeven under varying conditions of pressure, viscosity, and Temperature CapabilityOperating temperatures to 950 F (510 C).Maximum LifeOnly three moving parts; components are through-hardened tool and die steels to 62 HRc or better. Replaceablesleeve bearings for low-cost H-Series metering Pumps consistof two gears rotating in mesh within aclosely fitted housing that is comprised ofthree plates. The center gear plate fitsclosely around the outside diameter of themetering gears. The front and rear platessand-wich the center plate and restrictaxial movement of the gears.

4 Power istransmitted to the gears by the drive shaftwhich is either a through shaft, as in thepacking gland type pump, or a shaft witha tang that engages a universal seal cou-pling. The coupling is both a connectionto external power and the rotating mem-ber of a mechanical two seal designs, mechanical face seal and packing seal, have differentoperating requirements. As mentionedabove, the mechanical face seal designconsists of a rotating universal seal cou-pling that seals against a fixed seal all-metal seal design is dependentupon sufficient inlet pressure (usually 25 -50 psi) to force the inner rotating couplingagainst the outer stationary anchor. Thisdesign is commonly used in abrasive fluidor high temperature the metal seal requires sufficientinlet or working pressure to be effective, apacking seal design is also with this type of seal can have twoto four packing rings.

5 Common availablematerials are Grafoil and Teflon. To sealeffectively, fluid must be able to travel axially along the shaft. Weepage in thesepumps is a common occurrence andshould be Pumps are precision instruments requiring skilled and careful maintenance . Constructed of high-quality tool and die steels such as AISI D2, M2, M4and CPM-M4, or other high-performancealloys, they are tempered after heat treat-ment to hardnesses ranging from HRc 58to HRc 64. Since the thermal expansionrates for all three steels are almost identicaland are otherwise entirely compatible, it ispossible to combine them so as to takeadvantage of their best qualities in themost economical Type D2 toolsteel is often selected for the side andcenter plates as it offers good abrasionresistance, and it is the most economicalof the three steels we most commonlyuse.

6 Type D2 will also provide a higherdegree of corrosion resistance than M2 or portion of the side plate subject to the most wear is the shaft bearing hole, which has an easily replaceable,inexpensive sleeve bearing that can bemade of the extremely wear resistant Type M4 tool steel. Types M2 and CPM-M4steels are commonly used for the meteringgears, drive shaft, and universal seal coupling, due to their superior torsionalstrength and abrasion resistance for theseitems that are the most critical to propermetering H-Series Pumps are rear ported. Fluidenters the pump through a port drilled intothe rear side plate (the side opposite thedrive shaft). The fluid fills the exposed geartooth volumes and is transported aroundthe outer diameter of the gear pocket.

7 Asthe gears mesh together, the fluid is dis-placed in a very precise amount outthrough the discharge port that is drilledalongside the inlet port in the rear plate. Since Zenith Pumps are not self-prim-ing, a flooded suction is usually the mini-mum inlet pressure required. However,when high-viscosity fluids are used, moretime is required to fill the tooth a result, the inlet pressure must beincreased, or the gears must rotate at aslower speed to ensure complete volumefilling and to prevent Pumps rely on the metered fluid for lubrication of internal bearingareas. The pump should never beallowed to run dry or be allowed to runwith non-lubricating fluids such as of the close clearances in thebearing areas, lack of sufficient lubricationcan cause pump seizure or some othercatastrophic can occur across the faces of thegears from the high-pressure side to thelow-pressure side.

8 The amount of slipdepends on four factors: fluid viscosity,speed, differential pressure, and pumpclearances. Under reasonably stableoperating conditions, slip is repeatableand predictable,and pump operation canbe adjusted to Zenith H-Series are designed for high-temperature and high-pressure operation. As such, operating tempera-tures to 950 F can be achieved. Whenoperating at temperatures above ambient,heat jackets should be used and pumpsshould be heated slowly and uniformly toavoid warpage and internal should be carefully unpacked tomake sure that the shipment is complete. If any items are missing or damaged, thefreight carrier and Zenith should be the pump is composed of steel, it is a precision instrument.

9 Dropping thepump or hitting with a non-yielding materialcan cause serious damage to the compo-nents. All materials are through-hardened to maximum hardness resulting in a brittlematerial. Treat them as you would anyother precision gaging Pumps are shipped filled with arust preventative oil. Flush the oil thoroughlywith a cleaning solvent. It may be necessaryto disassemble the seal arrangement toremove all traces of the oil, but disassembleonly if flushing, the pump should be lubri-cated internally for start-up purposes. Poura suitable high-temperature lubricant intothe inlet port. Rotate the metering gearsuntil lubricant appears at the discharge the pump to a block with a flat-ness of true flat to.

10 0001" convex and a surface finish of 4 to 8 rms to preventleakage between the pump and bolts should be a Grade 8 orbetter. Make sure mounting bolts are lubri-cated with a high-temperature anti-seizecompound such as DAG Dispersion # should be alternately torqued ineven increments up to Zenith s recom-mended limit for the bolt size used. SeeTable 2 on page 10 for torque following is a brief standard installation procedure. For special applications, considerations, or simply to ask our advice, please contact ourApplications Engineering prepare the pump for use:1) Always flush out the plumbing system before connecting the ) Filters should be installed prior to the pump inlet that filter ideally to half thepump running ) Turn Pumps by hand before running.