Piston Pump b737

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Vickers®

Engine-Driven Pump for Boeing's B737-600/700/800/900P/N 849589Model PV3-240-18



2 EATON Aerospace Group TF500-23A October 2013

Eaton’s Vickers® part number

849589 (model PV3-240-18)

main Engine-Driven Pump (EDP)was specifically designed to

meet the requirements of the

Boeing 737-600/700/800/900

aircraft. This state-of-the-art

engine-driven pump offers

superior performance, higher

horsepower to weight ratio,

and lower operating costs.

It delivers 37.5 gpm (142 L/min)

at 3750 rpm and a 2850 psi

(19651 kPa). The design of the

pump is drawn from Eaton’s

Vickers product line of highly

reliable 2.40 cu/in displacement

pumps and has significant

reduction in weight and volume.

Model PV3-240-18 incorporates

the field proven, reliable model

PV3-240-2 and -10 pump

rotating components together

with improved reliability and

weight reduction technology

developed from the B777

engine-driven pump program.

Many piece parts from thecurrent model PV3-240

production models are

incorporated in the new unit,

which reduces spare parts

inventory requirements.

DESIGN FEATURES

Model PV3-240-18 incorporates

numerous design features to

improve the reliability and

maintainability of the unit.

Increased Fatigue Strength

All castings are designed for

improved fatigue characteristics

through specific structural

design based on finite element

analysis and use of improved

casting materials.

Proven Shaft and Yoke

Bearings

All bearings used in modelPV3-240-18 EDP carry the

same part numbers as model

PV3-240 series. This will

reduce spare parts inventory.

Hollow Drive Shaft

The drive shaft is hollow for

weight reduction. The internal

surface created by the weight

reduction is coated for

corrosion control.

Improved Cylinder Block

MaterialThe cylinder block is machined

from ductile iron to minimize

wear in the drive spline and

piston bores. Bronze plating

on the cylinder block surface

provides a durable bearing

surface for wear against the

tool steel valve plate.

Proven Yoke Design

The yoke used in model

PV3-240-18 is an exact “mirror

image” of the field provenmodel PV3-240-10 series yoke.

This is due to the fact that

model PV3-240-18 is a counter

clockwise rotation unit in the

Boeing 737-600/700/800/900

application. All material strength

requirements are identical. The

design allows for the use of

mid-grip helical thread locking

inserts. This eliminates the

need for time consuming safety

wiring of the shoe retaining

plate threaded fasteners.

Sleeved Actuator Piston Bore

A removable AISI 52100

bearing quality steel provides

the bearing surface for the

actuator piston.

Balanced Blocking ValveThe outlet blocking valve is

hydraulically balanced for rapid

response and ease of manufac-

ture. Viscous dampening of the

blocking valve piston retards

the closure rate to allow suffi-

cient decompression time for

the system outlet fluid prior to

valve closure.

Pressure Compensator

Stepped diameter seal glands

simplify assembly/disassembly

and minimize the risk of seal

damage. Double back-up rings

provide improved seal support

under high pressure condi-

tions. The pressure compen-

sator design also incorporates

viscous dampening to improve

dynamic stability.

Centrifugal Boost Impeller

Swept blade boost impeller

provides higher flow capability,

allowing for a smaller size

impeller.

Flange Mounted Electrical

Depressurization Valve (EDV)

The EDV is flange mounted

using two (2) threaded

fasteners. Step diameter seal

glands reduce the possibility

of seal damage during

assembly.

Removable Valve Plate

Separable valve plate design

allows for ease of assemble and

optimized material selection.

Single-piece Housing

The single-piece housing

design simplifies maintenance

tasks, reduces package

weight, and minimizes

envelope requirements. Most

importantly, it eliminates the

parting line between the

housing and the valve block.

Leakage from the high

pressure parting line seals at

this interface has traditionally

been one of the highest

causes of removal of model

PV3-240-2 and -10 series units.

Part Commonality

Model PV3-240-18 design

utilizes many parts common to

other Eaton models. This will

reduce the operators’ sparepart stock requirements.

Engine-Driven Pump Model PV3-240-18

Boeing 737



EATON Aerospace Group TF500-23A October 2013

BASIC PUMP OPERATION

The aircraft’s engine rotates

the pump drive shaft, and the

connected cylinder block and

pistons. Pumping action is

generated by piston shoes

which are restrained and slide

on the shoe bearing plate in

the yoke assembly. Because

the yoke is at an angle to the

drive shaft, the rotary motion

of the shaft is converted to

piston reciprocating motion.

As the piston begins to withdraw

from the cylinder block,

system inlet pressure forces

fluid through a porting arrange-

ment in the valve plate into

the cylinder bore. The piston

shoes are restrained in the

yoke by a piston shoe retaining

plate and hold-down retainer

during the intake stroke.

As the drive shaft continues to

turn the cylinder block, the

piston shoe continues

following the yoke bearingsurface. This begins to return

the piston into its bore, toward

the valve block.

The fluid contained in the bore

is precompressed then

expelled thought the valve

block outlet port. Discharge

pressure holds the piston shoe

against the yoke bearing

surface during the discharge

stroke and also provides the

shoe pressure balance and

fluid film through on orifice in

the piston and shoe

sub-assembly.

Engine-Driven Pump Model PV3-240-

Typical Pump Characteristics

A representative speed of 3750 rpm was used in developing curves





With each revolution of the

drive shaft and cylinder blockeach piston goes through the

pumping cycle described

above, completing one intake

and one discharge stroke.

High-pressure fluid is ported

past the blocking valve to the

pump outlet. The blocking

valve is designed to open and

remain open during normal

pump operation.

Internal leakage keeps the

pump housing filled with fluid

for lubrication of rotating parts

and cooling. The leakage is

returned to the system

through a case drain port. The

case relief valve protects the

pump against excessive case

pressure, relieving it to the

pump inlet.

CONTROL FEATURES

Normal Pumping Mode

The pressure compensator is a

spool valve that is held in the

closed position by an adjustable

spring load. When pump outlet

pressure (system pressure)

exceeds the pressure setting,

3025 psi (20857 kPa), and the

spool moves to admit fluid

from the pump outlet into the

actuator piston. (In the

schematic on page 5, the

pressure compensator is

shown at cracking pressure,

i.e., pump outlet pressure just

high enough to move the

spool to begin to admit fluid to

the actuator piston.)

At pump outlet pressures

below 3025 psi (20857 kPa), itis held at its maximum angle

in relation with the drive shaft

centerline by the force of the

yoke return spring. Decreasing

system flow demand causes

outlet pressure to become

high enough to crack the

compensator valve open and

admit fluid to the actuator

piston. This control pressure

overcomes the yoke return

spring force and strokes the

pump yoke to a reducedangle. The reduced angle of

the yoke results in a shorter

stroke for pistons and

reduced displacement.

The lower displacement

results in a corresponding

reduction in pump flow. The

pump delivers only that flow

required to maintain the

desired pressure in the

system. When there is no

demand for flow from the

system, the yoke angle

decreases to nearly zero

degrees stroke angle. In this

mode, the unit pumps only its

internal leakage.

Thus, at pump outlet pressure

above 3025 psi (20857 kPa),

pump displacement decreases

as outlet pressure rises. At

system pressure below this

level, no fluid is admitted

through the pressure

compensator valve to theactuator piston and the pump

remains at full displacement,

delivering full flow. Pressure is

then determined by thesystem demand.

Depressurized Mode

When the solenoid valve is

energized, outlet fluid is ported

to the EDV control piston on

the end of the compensator.

The high pressure fluid pushes

the compensator spool beyond

its normal metering position.

This removes the compensator

from the circuit, and connects

the actuator piston directly tothe pump outlet.

Outlet fluid is also ported to

the blocking valve spring

chamber. This equalizes

pressure on both sides of the

blocking valve causing it to

close due to the force of the

blocking valve spring. This

isolates the pump from the

external hydraulic system.

The pump strokes itself to

zero delivery at an outlet

pressure that is equal to the

pressure required on the

actuator piston to reduce the

yoke angle to nearly zero. This

depressurization and blocking

feature can be used to reduce

the load on the engine during

start-up and, in a multiple

pump system, to isolate one

pump for check out purposes.





DISPLACEMENT

CU IN / REV

RATED

SPEED

(RPM)

3750

RATED INLET

PRESSURE

(PSIA)

3

@ 6 GPM

RATED DISCHARGE

PRESSURE

RATED

DELIVERY

RATED INLET

TEMPERATURE

225ºF

(107.2ºC)

FLUID

BMS-3-11

MAXIMUM

WET WEIGHT

PV3-240-18A AND

PV3-240-18 MOD. A

MAXIMUM

WET WEIGHT

PV3-240-18 AND

PV3-240-18 MOD. B

10.76(273.30)

5.54

(140.71)

3.06(77.72)

.443 (11.25)

9.36 (237.74)

7.62 (193.54)

32.9 LBS

(14.92 KG)

32.0 LBS

(14.51 KG)37.5 GPM

(142 L/M)2.403025 PSIG

(2087 KPA)

1.81(45.97)

Dimensions shownin inches (mm)




5.0(127.0)

.143 (10.49)

.750 (19.04) .094 (2.387)

.60 (15.23)4.87 (123.69) MAX

.90 (22.86)

3.14

(79.75)

2.05

(52.09)

.49

(12.44)

.27

.07

(6.85)

(1.77)

4.5 (114.30)

4.3 (109.21

2.96

(75.18)

2.32

(58.92)

.11 (2.79)

.34 (8.6

.14 (3.5


Dimensions shownin inches (mm)



Copyright © 2013 EatonAll Rights ReservedForm No. TF500-23A(Supersedes PN140-13)October 2013

EatonAerospace Group9650 Jeronimo RoadIrvine, California 92618Phone: (949) 452 9500Fax: (949) 452 9990www.eaton.com/aerospace

EatonAerospace GroupFuel & Motion Control Systems Division5353 Highland Drive

Jackson, Mississippi 39206-3449Phone: (601) 981 2811Fax: (601) 987 5255

Piston Pump b737

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