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CASE STUDIES:

48" Diameter Sewage Pump Impeller

Problem:

The impeller for one of N.Y.C. main sewage pumps was found "Practically Destroyed".

Possible Solutions:

• Get a new impeller from the manufacturer. This involved a waiting period of 48 - 52 weeks, a good long term
solution, which meant having the pump out of service for (1) one year.

• Call in several vendors so that they could offer a more viable solution. Every vendor practically gave up;
saying that since more than half of the impeller was missing, there was nothing that could be done.

Frontline’s Solution:

Rebuild the impeller as close as possible to the original dimension. The customer provided Frontline with a drawing
of the impeller and we went to work. See detailed description below.

This is what was left over

of the 48"

diameter impeller.

We had a foundry cast a

ring and set it at the

right height following

a customer's

dimensional drawing.

Following the existing

profile, we built a vane

made out of reinforced plaster. Then we cut out the

vane and sent it to a

foundry to be reproduced.

The foundry cast

(4) four identical vanes

(2-shown in photo).

We then trimmed off

the existing impeller

vanes uniformly.

The (4) four new vanes

were carefully set in place

and welded to the ring

and to the hub.

The I.D. and O D. of the

suction ring was then machined according to the manufacturer's specifications.

The impeller was then put thru an extensive phase of hand grinding to bring the

(4) four vanes to a uniform and dimensionally

symmetric profile.

A stainless steel wear ring was then "shrunk on" and

pinned to the impeller.

The impeller was

then secured to a shaft

provided by the customer.

Impeller and shaft assembly being lifted and secured

onto the balancing machine.

Operator getting ready

to dynamically balance

the rotor.

The Results Were:

The entire job took only 5 1/2 weeks, allowing the customer to put a very important piece of equipment
back on line at a fraction of the original cost estimate, and with a much shorter downtime than originally anticipated.

Frontline Industries, Inc. | 990 Chancellor Avenue | Irvington NJ 07111 | 800.890.7325 | e-mail: info@frontlineindustries.com