Attività

My wife often asks me why I still do consulting work. She wonders why I happily leave the comfort of my office to crawl all over hot, dirty, smelly hydraulic equipment.

For starters, I actually enjoy it. Secondly, it keeps me sharp. But perhaps most importantly, it keeps me in touch with the issues that hydraulic equipment users must grapple with.

One of the lessons I've learned over the years is that in the early stages of a consulting assignment, it is better to ask good questions rather than dispense good advice.

Pump Failures

A recent client had a series of catastrophic pump failures. These pumps were achieving less than half their expected service life. So naturally, the company wanted some answers. At our first meeting, the client opened proceedings with a brief history of the machine and an account of the events leading up to the failures. He then pushed a stack of oil analysis reports across the table.

Ask the Basic Questions

After taking notes on what I'd just been told, I fired off my first question: "What is the system's normal operating temperature?" The response was stunned silence. Client shrugs his shoulders.

"OK, what is the system's usual operating pressure range?" Blank look from client. "I don't know; we don't monitor either of those things."

At the end of this meeting, we walked through the control room. Both the operating pressure and temperature were displayed on the default PLC screen – albeit along with a lot of seemingly more important production information. Say no more.

Gathering Information

This information is easy to collect. It can give valuable insight to the health of your equipment and is essential data if failure analysis is required. Here is how I recommend you accomplish this task:

First, you need an infrared thermometer, also called a heat gun. If you don't have one, you'll need to invest around 100 bucks to get one and then familiarize yourself on how to use it.

Next, using a permanent marker or paint stick, draw a small target on the hydraulic tank below minimum oil level and away from the cooler return. Label it 1. This marks the spot where you'll take your tank oil temperature readings.

By the way, the purpose of these targets is that regardless of who takes the temperature readings, they'll be taken from the same place each time.

Install a pressure gauge or transducer to record operating pressure if one is not already available. If the system is a closed-circuit hydrostatic transmission, install a similar device to record charge pressure.

With that accomplished, now draw up a table like Table 1 to record the date, time, ambient temperature, operating temperatures and operating pressure(s). Note that there is little point in recording the temperature across the heat exchanger if the fan or water pump isn't running. And, charge pressure is relevant only to closed-circuit hydrostatic transmissions.

In terms of compiling this data, it's a good idea to take readings on the hottest and coldest days of the year, and on a couple of average-temperature days in between. This provides a baseline of information. Beyond that, taking readings at regular intervals – each day or shift, for example – can provide early warning of impending problems. And if the system starts to give trouble, taking a set of readings will reveal if the machine is operating outside its normal parameters.