Woodward 20 Series Rotary Gear Pumps

Note: Because of different pump sizes, there can be multiple part numbers for each reference number.

Woodward 20 Series Rotary Gear Pump Parts and Reference Numbers:

Reference Numbers are taken from Woodward manual 15001H (Rotary Gear Pumps Woodward Hydraulic Governors Manual 15001H)

This information can come in handy as customers evaluate the status of their existing pumping systems.

Brazed Tank - Inside

Some customers have expressed concerns over the riveted tanks used on early 20 Series Pumps. While the exact factors of safety and modern day code compliance may be in question, it should be noted that the tanks are not just riveted together, they are also brazed as shown in the two photos below.

Size 26 V Belt Kit

The original chain drive systems provided with some 20 Series Pump systems have proven to be problematic. A replacement system has been designed to change the chain system to a V-Belt system. A kit can be provided based on the following information: pump size, pump serial number, motor shaft size, motor frame size.

Chain Drive Replacement System:

    1) AGC Supplies a Reconditioned Pumping Element Assembly
    2) Customer Removes Old Pumping Element Assembly
    3) Customer Installs New Pumping Element Assembly
    4) Old Pumping Element Assembly is Returned to AGC

The replacement/exchange process consists of four steps:

The loss of pumping ability does not mean that the system must be replaced. The degradation in pumping ability is usually the result of excessive end clearance and tolerance issues within the pumping element chamber.

After many years of service, the 20 Series pump may begin to lose its ability to pump effectively. This becomes apparent when the pump is required to pump air into the accumulator during the pump balancing procedure.

Cutaway View of a 20 Series Pump

       Parts and Gaskets Required for Routine Maintenance
       Maintenance Recommendations
       Pump Air/Oil Balancing Procedures
       Replacement Exchange Program - Pumping Elements
       Drive System Replacement - Chain to V-Belt Drive Upgrades
       On Site Service and Support

Typical 20 Series Pump

The size of the pump is important for proper support. The pump size and serial number are marked on the side of each pump tank.

     Size 21
     Size 23 1/2 to 24 1/2
     Size 25 to 26 1/2
     Size 27 to 27 1/2

These pumps were supplied in multiple sizes:

A unique feature was its ability to recharge its own air head. With proper maintenance and care even the oldest models can continue to provide reliable service well into the future.