triplex pump part 1

Triplex PumpTraining Module

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December 1999

Schlumberger Confidential

Introduction

This module introduces you to the Dowell PG Series of Triplex Pumpscommonly used in our Cementing, Acidizing and general pumpingwork. The aim is to give you a thorough understanding of the ratings,limitations, care and maintenance of one of the most important piecesof machinery used by Dowell. More than 90% of our revenue ispumping related. So you need to know all about our Triplex Pumps,caring for them and maintaining them according to our standards.

Objectives:

To provides an overview of the Triplex Pump, its main componentsand operating principles.

To describe the basic specifications and ratings of the Triplexpump.

To review the lubrication system for this piece of machinery.

To discuss STEM operations.

To explain and teach the proper care and maintenance of theTriplex Pump and its ancillary equipment, including how to repacka fluid end correctly.

The Appendix includes color diagrams of the Triplex Pump andFluid End, with part numbers. There is a Trouble-shooting Guidefor the more common problems you might encounter in everydayservice, relevant Maintenance Bulletins.

1.0 An Overview of the Triplex Pump

The Triplex Pump is the general name given to any type of pumpassembly having three (cylinders) plungers. By the same reasoning,the Quintiplex Pump will have five cylinders and the Duplex Pump(seen working as mud pumps) will have two cylinders.


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December 1999


Triplex Fluid End


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December 1999


Quintuplex Fluid End


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December 1999


The purpose of any pump is to convert mechanical energy, provided bymotors, engines, turbines and other prime movers into fluid energy asefficiently as possible. The pump assembly has to be light, compact,simple and easy to maintain whilst providing the efficiency and the powerrequired. It is the most efficient type of pump for pumping abrasive ladenfluids at high pressures (1000 psi and above) and requiring the leastmaintenance is the Reciprocating Plunger type pump. For maximumsmoothness (no pulsations), at least 3 plungers are required for properbalancing of the load.

Most Reciprocating pumps such as the Triplex pump are considered tobe positive displacement pumps, this means that as the pump is working,100% of the fluid that enters each cylinder will exit each cylinder. In aCentrifugal Pump fluid exiting the pump can be stalled and the fluid inthe pump will relieve to the suction side of the pump. In the Triplex pumpthe fluid on the discharge side cannot be stalled, as the plunger will applyas much force as that being applied to through the power-end. This is thereason we must utilize safety devices such as burst disc in the suctionvalves of the Fluid end and Over-pressure shut-downs on the controls ofthe Triplex pumps.

Every type of pump assembly has a designed operating limitation basedon pressure, rate or horsepower ratings.


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December 1999


There are mechanical limitations as to how much horsepower can besupplied to any given pump, and the pump cannot add or create any morehorsepower than what is put into it.

A simple explanation is:

Horsepower output = Horsepower in efficiency lost.

Conventional prime movers output their power by means of rotation andtorque on a shaft. A pump assembly needs to convert this rotationalpower by some means into fluid hydraulic power, which is measured bythe combination of volume of output and pressure at that output rate.

Most types of plunger pump assemblies have 3 main components:

1. A Speed Reducer to reduce the input shaft rpm, i.e. to change the highspeed low torque shaft output from a prime mover to a low speed hightorque shaft input to a pump. Dowell uses Chain Cases and gear typespeed reducers.

2. On a reciprocating pump, a device called the Power End converts thisrotational power into reciprocating power, which is transferred to theFluid End to transfer the power to the fluid.

3. The Fluid End receives the power from the Power End, and by usingthe plungers, fluid received at low pressure is forced or pushed by theplungers so that it exits the fluid end at a much higher pressure.


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December 1999


Dowell uses various combinations of transmissions, chain cases andpower ends to cover our range of pumping requirements efficiently. By far,the most commonly used pump in our business is the PG Series ofTriplex Pumps, which we use to pump fluids such as cement slurries andcorrosive fluid systems at high pressures and rates.

1.1 The Chain Case

Most of Dowell's Triplex Pumps (with the exception of Turbine-drivenunits and some Stimulation units) use Chain Cases as the first stage ofinputting power from the output shaft of a prime mover, which could be anengine/transmission combination, or a electric motor being used to drive apump.

The Chain Case performs 2 important functions:

1. The chain case provides flexibility when mounting the Pump assemblyin different locations with respect to the prime mover output shaftcenter-line. Chain case can be assembled to accept the input fromether side and mounted on either end of the power end as seen in thepicture below.


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2. The chain case converts a low torque high rpm engine output to a hightorque low rpm output more suited to the requirements of the powerend. The ratio of reduction on a P.G. Series Pump is 1:675 (sprocket27-40 tooth)

This drawing shows a typical chain case. A chain travels over the uppersprocket mounted on the pump pinion shaft (40 teeth) and over the lowersprockets driven by the prime mover (27 tooth). When the prime moverrotates the lower input shaft, the chain transmits the power to the upperoutput (pinion) shaft and rotates it as well. This shaft then transfers therotation to the Pinion Shaft of the power end. The different diameters ofthe two sprockets in the chain case acts to reduce the prime moversoutput speed (rpm) and increase the torque input to the pump.

Each chain case is secured to the chassis or skid by means of a pair ofTorque Rods. They prevent the chain case from moving when power isapplied.


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1.2 Power End

The Power End functions very much the same way as does a crankshaftin a conventional motorcar engine. The output shaft of the chain case isactually the P.G. Series pump pinion shaft. The pinion shaft drives thecrankshaft via the crankshaft bull gears. The gear ratio between thepinion shaft and bull gears is 1:4.31 (on the P.G. series pump). By usingeccentrics the rotation of the Mainshaft is changed into a reciprocatingaction. This reciprocating force is transferred to the Connecting Rodsand Crossheads, which in turn move the plungers in the Fluid End.


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Most of the load on the triplex pump assembly is taken by the Power End,especially by the Eccentrics. It can be easily seen that the Crossheadsand Connecting Rods exert a force back to the eccentrics while pumpingunder pressure, and if this force exceeds a certain design limit, the powerend will quickly fail. This limitation is commonly called the Maximum RodLoading.

One of the limiting factors of Rod load is the amount of force that theConnecting rod can withstand before the lubrication is squeezed out frombetween it and the eccentric bushing causing metal-to-metal contact.When this occurs, failure is imminent.

The centerline of the Main Shaft in relationship to the centerline of theeccentrics determines the length of the Stroke of the power end.

There are basically three types of power ends made by Dowell.

They are:

(a) The 5-inch stroke (PG Series with Rod Load = 110,000 lbs), rated at285 BHP (Brake Horsepower) input and are the most commonly used incementing operations. They are available in either Steel for offshoreapplication or Magnesium for truck applications where weight is aconsideration.

(b) The 6-inch stroke (PC, PT with a Standard Rod Load = 195,000lbsand the upgraded version with Rod load = 237,000) and PQ Serieswith Rod Load = 165,000 LB)


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(c) The 8-inch stroke (PD Series with Rod load = 115,000 LB).


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Most of the P Series power ends except for the PG Series are beingphased out as the new generation of power ends and fluid ends will taketheir place. The Gardner Denver GD 700 Lite Weight is one of thereplacement power ends being installed on some of the new equipmenttoday.

The GD 700 is available with ether a right angle drive gear as shown above andalso available with the standard direct drive into the pinion shaft


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December 1999


Two other common type of Power ends are:

OPI (Odessa Pump Inc) which was the original Manufacture of thisCrankshaft style Fracturing Triplex pump in the early 70s. Later othermanufactures made similar versions of the OPI style power end. Dowellat the time was purchasing the power ends but manufacturing our ownfluid ends to use with the OPI power ends.

In the past Gardner Denver has purchased a number of themanufactured OPI style Power Ends and today GD manufactures theGD1250, GD2000 as replacements for the OPI 1300 and 1800 seriespower ends. The Number indicates the Max Brake Horsepower input. Forexample GD 1250- 1250 brake horsepower input.

The GD 1250 power ends have a Rod Load rating = 200,000 lbs.


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The GD2000 power end have a Rod Load rating = 237,000 lbs. This is adirect replacement for the OPI 1800 power end.

The SD2000 Power Ends were manufactured for Dowell by TwentiethCentury Manufacturing for use with the In-Line Fluid ends. Although thelife of the In-Line fluid end was short lived the SD2000 with its 325,000 LBRod Load was refitted to accept a cross-bore style fluid end and is a verygood Frac pump in our fleet today.


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1.3 Fluid End

The Fluid End of the pump assembly is the part of the pump, whichreceives fluid at low pressure, applies horsepower to the liquids, anddischarges the liquid at high pressure. The mechanical pumping action isagain very similar to that of a conventional piston-type internalcombustion engine or a reciprocating piston type air compressor. Thistype fluid end is referred to as a Cross-Bore Type fluid end because thetwo borings intersect each other to create the cylinder.


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As the plunger is drawn towards the Power End (suction stroke), thepressure inside the chamber between the Suction and Discharge Valvesis reduced. This causes the suction valve to lift and the fluid to be drawninto the suction manifold, through the suction ports, around the suctionvalves, and into the chamber. At this moment, the suction valve is openedby the fluid entering the fluid end, and the discharge valve is kept closedby its check valve-type action and the discharge valve spring.

When the plunger starts to move in the opposite direction towards theFluid End (discharge stroke), the fluid inside the chamber, beingincompressible is forced out. The suction valve closes immediately like acheck valve, and the fluid then lifts the discharge valve from its valve seatand is forced out around the discharge valve and into the pump dischargechamber.

The usual suction or intake pressure is low (about 30 psi) but thedischarge pressure can be in the range of thousands of psi. Some FluidEnds made by Dowell are rated to work at 15,000 psi working, pressureand some can even go as high as 20,000 psi.


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December 1999


The plungers, in the fluid end, receive energy from the power end. Eachtime the main shaft makes one revolution, all the plungers in the pumpmakes a complete cycle (i.e. a stroke forward and backward). Therefore,by counting the revolutions of the main shaft and multiplying the RPM(revolutions per minute) times a volume factor, we can get a volumeamount in BPM (barrels per minute), liters per minute or accumulativeamount of fluid pumped. This volume is only a mechanical indication ofvolume, not an actual volume, so if the supply to the pump is restricted,the volume calculated this way can be inaccurate. That is why in Dowellwe also use absolute volume measures like unit displacement tanks.

Fluid ends are designed for specific series of power ends, that is, thestroke length of the fluid end is always the same as the stroke length ofthe power end. Fluid ends are manufactured with various plungerdiameters for each series of power end. Plunger diameters range from thesmallest diameter of 2 inch to the largest of 7 inch. Obviously, thelarger the plunger diameter, the larger the volume of liquid displaced perstroke of the plunger(s). However, the largest diameter plunger does notnecessarily mean the best. By making simple calculations, it can be seenthat for a particular Maximum Rod Load (as limited by each power endseries), the maximum pressure the fluid end can pump is limited by thediameter of the plungers. So, the larger the plunger diameter, the lower isthe Maximum Pressure Rating of the fluid end. Should the Fluid End beused to pump fluids in excess of its designed working pressure rating, thefirst component of the triplex assembly that will fail is the power end.Therefore, it is extremely important that the fluid end is not taken beyondits maximum pressure ratings. Failure will occur because the forceexerted on the eccentric bushing (bearing) and the crosshead pin bushingcauses the lubrication to be squeezed out creating a metal-to-metalcontact. Once this occurs there is no reversing the damage andcatastrophic failure is inevitable.


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Each type of fluid end can easily be identified by a code of letters andnumbers, which are stamped on each fluid end. An example: a fluid endstamped TG06 would mean it is a 3 3/4 diameter plunger rated at amaximum working pressure of 10,000 psi and a maximum output of 5.8BPM for a 5 inch stroke (PG series) pump. There is also a serial numberstamped with the code to keep track of individual fluid ends. The fluid endspecifications, identification codes, volume factors, plus the rate andmaximum pressure ratings for each fluid end are given in the appendix ofthis manual, the Dowell treating Equipment Manual or on a "quickreference" card ratings shown below for different power end series:

Power end data:

Power end = 5 stroke PG series

Maximum rod loading = 110,000 lb

4.32 ratio, internal gears

Fluidend

Plungersize/diameter(inches)

Standardmaximumpressure

(Psi)

Pumprate

(Bpm)

bbl/rev.

Pinion

Shaft

bbl/rev

Mainshaft

TSO 2-1/2 20,000 2.6 0.00170 0.0074

TRO 3 15,000 3.7 0.00245 0.0106

TGO 3-3/4 10,000 5.8 0.00383 0.0166

TLO 4-1/2 7,000 8.3 0.00552 0.0238

THO 5 5,500 10.3 0.00681 0.0294

Power end data:

Power end = 6 stroke MD 1000




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December 1999


Fluidend



(Psi)

Pumprate

(Bpm)

bbl/rev.

Pinion

Shaft

bbl/rev

Main shaft

M 3 20,000 7.1 0.00308 0.0127

F 3-3/4 12,200 11.1 0.00482 0.0199

E 4-1/2 8,500 15.9 0.00694 0.0286

D 5 6,800 19.7 0.00856 0.0353

Power end data:

Power end = 6 stroke MD 1000



Fluidend



(Psi)

Pumprate

(Bpm)

bbl/rev.

Pinion

Shaft

bbl/rev

Mainshaft

M 3 20,000 5.3 0.00232 0.0127

F 3-3/4 12,200 8.3 0.00363 0.0199

E 4-1/2 8,500 12.0 0.00523 0.0286

D 5 6,800 14.8 0.00645 0.0353


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December 1999


Power end data:

Power end = 8 stroke GD 700 series


10:1 Ratio

Fluidend



(Psi)

Pumprate

(Bpm)

bbl/rev.

Pinion

Shaft

bbl/rev

Mainshaft

FGD 3-3/4 15,800 7.9 0.00265 0.0265

XGD 4 13,900 9.0 0.00301 0.0301

EGD 4-1/2 11,000 11.4 0.00381 0.0381

HGD 5 8,900 14.1 0.00471 0.0471

IGD 5-1/2 7,400 17.1 0.00570 0.0570

YGD 6 6,200 20.3 0.00678 0.0678


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Power end data:



6:1 Ratio

Fluidend



(Psi)

Pumprate

(Bpm)

bbl/rev.

Pinion

Shaft

bbl/rev

Mainshaft

FGD 3-3/4 18,000 7.9 0.00441 0.0265

XGD 4 16,000 9.0 0.00502 0.0301

EGD 4-1/2 12,500 11.4 0.00636 0.0381

HGD 5 10,000 14.1 0.00785 0.0471

IGD 5-1/2 8,400 17.1 0.00950 0.0570

YGD 6 7,000 20.3 0.01130 0.0678

Power end data:

Power end = 8 stroke PD 1250 series


5.0 Ratio, internal gears

Fluidend



(Psi)

Pumprate

(Bpm)

bbl/rev.

Pinion

Shaft

bbl/rev

Mainshaft

TTO 2-1/2 20,000 3.1 0.00235 0.0118

TMO 3 15,000 4.4 0.00339 0.0170

TFO 3-3/4 10,500 6.9 0.00530 0.0265

TEO 4-1/2 7,500 9.9 0.00763 0.0381

TDO 5 6,000 12.2 0.00942 0.0471

TNO 5-3/4 4,500 16.2 0.01246 0.0623

TJO 6-3/4 3,500 22.3 0.01716 0.0858

TKO 7-3/4 2,500 29.4 0.02263 0.1131


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Power end data:

Power end = 8 stroke OPI 1800, HD 2000 series

Maximum rod loading = 195,000 lb (standard), 237,000 (upgraded)

6.353 : 1 Ratio

Fluidend



(Psi)

Pumprate

(Bpm)

bbl/rev.

Pinion

Shaft

bbl/rev

Mainshaft

FOPI 3-3/4 17,500 8.7 0.00417 0.0265

EOPI 4-1/2 12,000 12.6 0.00600 0.0381

HOPI 5 10,000 15.5 0.00741 0.0471

IOPI 5-1/2 8,000 18.8 0.00897 0.0570

UOPI 6-1/2 6,000 26.3 0.01253 0.0796

JOPI 6-3/4 5,500 28.3 0.01351 0.0858

Power end data:

Power end = 11 SD 2000 series, In-line pump

Maximum rod loading = 350,000 lb (standard)

8.4958: 1 Ratio

Fluidend



(Psi)

Pumprate

(Bpm)

bbl/rev.

Pinion

Shaft

bbl/rev

Mainshaft

H-205 5 16,500 14.5 0.0647

I-255 5-1/2 13,500 17.5 0.0783

U-265 6-1/2 10,000 24.5 0.1094


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Power end data:

Power end = 11 SD 2000 series, Cross Bore pump

Maximum rod loading = 350,000 lb(standard)

8.4958: 1 Ratio

Fluidend



(Psi)

Pumprate

(Bpm)

bbl/rev.

Pinion

Shaft

bbl/rev

Mainshaft

H-205 4-1/2 20,000 12 0.0536

I-255 5-1/2 15,000 17.5 0.0783

U-265 6 12,500 21.2 0.0946

Note: Pumps volumetric efficiency = 97%

Many fluid end parts such as valves, valve seats, springs are interchangeablewith fluid ends of different series (stroke length) pumps. Other parts such aspackings, adaptor rings, spacers, gland nuts and lantern glands are alsointerchangeable for use in pumps with plungers of the same diameter regardlessof the stroke length. (A chart showing interchangeable parts is included in theappendix:


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PG Series Fluid End Assembly


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The GD lite weight series fluid ends utilize a different concept in fluid endadaptability. They use a stuffing box as shown below that threads into the fluidend, this stuffing box is were the packing seals seat. Some have different sizestuffing boxes as listed below. The pressure rating will due to the power endsRod load Rating. The same fluid end will fit on a GD 700 or GD 1250 powerend.You should reference either the Treating Equipment manual or the Pump Cardvia the Web for the latest and most accurate ratings.

The High Pressure Fluid End

3-3/4- (FGD) not Stuffing Box design (Conventional Design)

The Medium Pressure Fluid End

4-1/2- (EGD)

5 - (HGD)

5-1/2 (IGD)

The Low Pressure Fluid End

5-1/2 (IGD)

6 (YGD)

6-1/2 Under development

Incidentally the new fluid ends were designed to accept and use the samepacking and brass as that used in the same size fluid end in the PG seriesPower End.

The plungers are different.


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10:1 Ratio

Fluidend



(Psi)

Pumprate

(Bpm)

bbl/rev.

Pinion

Shaft

bbl/rev

Mainshaft

FGD 3-3/4 15,800 7.9 0.00265 0.0265

XGD 4 13,900 9.0 0.00301 0.0301

EGD 4-1/2 11,000 11.4 0.00381 0.0381

HGD 5 8,900 14.1 0.00471 0.0471

IGD 5-1/2 7,400 17.1 0.00570 0.0570

YGD 6 6,200 20.3 0.00678 0.0678



6:1 Ratio

Fluidend



(Psi)

Pumprate

(Bpm)

bbl/rev.

Pinion

Shaft

bbl/rev

Mainshaft

FGD 3-3/4 18,000 7.9 0.00441 0.0265

XGD 4 16,000 9.0 0.00502 0.0301

EGD 4-1/2 12,500 11.4 0.00636 0.0381

HGD 5 10,000 14.1 0.00785 0.0471

IGD 5-1/2 8,400 17.1 0.00950 0.0570

YGD 6 7,000 20.3 0.01130 0.0678


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2.0 Specifications and Ratings for the PG Series Triplex Pump

2.1 Chain caseCase Steel (fabricated)Chain Diamond 80-4Ratio 27:40RPM Maximum input 2240 RPMRPM Maximum output 1512 RPMRated HP 353Rotation Normal rotation is counter clockwise facing drive end of

the triplex pump pinion shaft.Coupling input: spicer 1700 series drive flange output: chain case

sprocket mounted on triplex pump pinion shaft.Weight 500 lbs (227 kg)

The Chain Case can be extended by adding a spacer and increasing thechain length. Most Dowell Twin Pump Cement Units (CPS, CPT) use astandard 23.15" center-to-center Chain Case for the Down Hole Pump,which has a chain that is 90 pitches long. The Mixing Pump uses anextended Chain Case (6" extension section) which increases the ChainCase length to 29.15" center-to-center and uses a chain that is 95 pitcheslong. Both chains are known as Quad 80 chain, which means 80 pitch(length from pin to pin) and 4 links wide.


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Typical Twin P.G. Pump Layout

The torque arms are designed to stabilize and control the reaction of the torquebeing applied through the chain case. The torque arms are to be adjusted asfollows. The torque arms have left hand threads on one end so they will changelength when rotated. Set one of the torque arms to the desired position. Assuringthe driveshaft clears all obstructions. Then adjust the other torque arm in anydirection to tighten and lock the chaincase into position. Tighten all locking nutsin position.


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2.2 Power EndPump Model PG05 (steel)

PG03 (magnesium)Type Single Acting Triplex Reciprocating

Positive DisplacementConfiguration Horizontal-in-LineStroke 5"(127mm)Maximum Input Speed 2240 RPMMaximum Mainshaft Speed 350 RPMMaximum Pinion Shaft Speed 1512 RPMMaximum Rod Load 110,000 lbs (50 tonnes)Maximum Recommended Oil Temperature 160 degF (70 deg C)Maximum Input Horse Power (HP) 353 HPRated Output Hydraulic Horsepower 300 HHP (224 kW)Mechanical Efficiency (with Chain Case) 85%


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The P.G. Pump can be configured in two different ways so that the powerend can be driven from the left or right hand side. These twoconfigurations do not require different parts but is distinguished by theway the pinion shaft is installed in the power end frame. When changingthe position of the pinion shaft the timing gears must be re-timed.

Note:

There are a few instances where the P.G. series power end turns in theopposite direction (Reverse Rotation). This is not common, but you willfind it on units where the two P.G. Pumps face each other (mirror image)and are driven by conventional diesel engines.

triplex pump part 1

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