Vickers® Engine-Driven Pump for Boeing's B737-600/700/800/900

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 the current 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 model PV3-240-18 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 Material The 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 proven model 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 Valve The 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’ spare part stock requirements.

Engine-Driven Pump Model PV3-240-18

Boeing 737

EATON Aerospace Group TF500-23A October 2013 3

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 bearing surface. 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.


Typical Pump CharacteristicsA representative speed of 3750 rpm was used in developing curves



With each revolution of the drive shaft and cylinder block each 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), it is 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 reduced angle. 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 the actuator piston and the pump remains at full displacement,

delivering full flow. Pressure is then determined by the system 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 to the 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.





DISPLACEMENTCU IN / REV

RATEDSPEED(RPM)

3750

RATED INLETPRESSURE

(PSIA)3

@ 6 GPM

RATED DISCHARGEPRESSURE

RATED DELIVERY

RATED INLET TEMPERATURE

225ºF (107.2ºC)

FLUID

BMS-3-11

MAXIMUMWET WEIGHT

PV3-240-18A AND PV3-240-18 MOD. A

MAXIMUMWET 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)2.40

3025 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 (8.63)

.14 (3.55)


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

Documents

Vickers® Engine-Driven Pump for Boeing's B737-600/700/800/900