Problem Solving Article: THE PUMP THAT WOULDN'T 

The First Article in a Series of Problem Solving Articles in an Industrial Setting

The pump that wouldn't pump was located below a tank into which olives passed on their way from storage to processing. The pump was supposed to be able to pump non-food grade olive oil from the tank to an oil collection tank for further processing into livestock feed.

The pump was piped to allow suction from collection points at the top of the tank during operation and from the bottom of the tank after the tank was mostly emptied. The discharge pipe to the storage tank was over 300 feet long.

Unprocessed olive oil congeals to a lard-like substance and will adhere to the insides of pipes and totally block the pipe if not cleaned. The discharge pipe had a steam pipe connection to keep the pipe open and cleaned.

As the Maintenance Supervisor of a recently reopened olive cannery, it was my responsibility to identify the problem and correct it. When the pump was not able to pump the olive oil, it was dumped into the plant waste water system.

The waste water discharged into a 100,000 gallon collection tank where some of the oil was inefficiently scraped from the top of the of the waste water before the waste water was discharged into the Tulare County waste water collection, treatment and disposal system.

The county did not want the olive oil and other solids that the plant was disposing of in the waste water. The county imposed a progressively escalating scale of fees on the materials in the waste water. 

These fees, when coupled with the total amount of waste water, ran into the hundreds of thousands of dollars per year for the plant. This money came directly from the bottom line and every dollar spent meant a lot of olives had to be sold to make up for those dollars.

None of the mechanics had told me the pump was not working. I noticed the oil being dumped into the waste water drains one day and asked the shift mechanic what the problem was.

The mechanic turned on the pump and showed me that the shaft of the motor was turning but nothing was being pumped. He explained the system to me and showed me the piping. He told me that it had not worked for six months or more prior to the plant shutdown and sale.

The next day I resolved to investigate the system and find out what was going on. I wanted to reduce those fees paid to the County.

When I turned the pump electric motor on I checked that the shaft was indeed turning. I used a flashlight because the pump and motor were in the shade of the tank.

From past experience I knew that a shaft can break. The motor shaft was broken right at the point where the shaft entered the pump.

I called the electricians and mechanics on duty to show them the problem. This exact problem has only occurred three times in my career, however, it can be a real ballgame breaker when it does occur.

The electrician and mechanic locked out the motor power supply and replaced the motor and pump with a new set. When we ran the pump, it still would not pump anything.

We figured that the pipeline was plugged with congealed oil and needed to be steam cleaned. The steam line had not heat so we traced the pipe back to a shut supply valve and opened it.

Steam immediately started coming from the pump. The local valve and two non-return valves were probably stuck in the open position.

We shut the steam supply valve and locked it off. After bleeding of the steam in the lines, the mechanic pulled the local steam valve and the non-return valves. 

All three valves were the wrong type for handling the steam temperature and pressure. All the valves were replaced with the correct type and we were ready to try to steam open the discharge pipe.

The steam was opened into the pipe and gradually the pipe started warming up in the direction of the collection tank. Clearing the pipe took four hours and the pump worked after the pipeline was cleared.

I wrote a procedure for pumping the oil and cleaning the pipe after each pumping session. The procedure was laminated and posted at the site for mechanics and production operators to use during operations.

The problem was successfully solved and reduced the plant's grease and solids discharge into the waste water.

Feel free to copy this article in it's entirety as long as you include the credits below. Thank you for spreading the knowledge.

Author: Larry Bush 
Profile: Electrician in industrial, construction, marine, and food industries for 47 years, with 22 of those years in management.
URL: http://www.reliability-consultant.com