WHEN TO USE DYNAMIC EQUIPMENT BALANCING TO INCREASE SERVICE LIFE

By Rod Garing

WHEN SHOULD I GET MY EQUIPMENT BALANCED?

Equipment needs to be balanced when it’s new or has been pulled for rebuilding or repair.

It is critical that new equipment is balanced to ensure a long trouble-free service life. Differences in castings, including voids, density and porosity, can contribute to unbalanced rotors on new equipment. Machining and fabrication tolerances also play a role in unbalanced rotors.

Equipment that has been in service for an extended period of time can develop an unbalanced rotor. Buildup from deposits, corrosion and wear contribute to this unbalance.  Cavitation in pumps can also accelerate an unbalanced condition.

WHY IS EQUIPMENT BALANCING SO IMPORTANT?

Unbalanced rotors cause stress on the supporting structure of the equipment—this includes bearings, seals and shafting. Bearings will experience an increased load resulting in decreased service life. Unbalanced rotors also produce vibration, which causes a number of issues. Vibration may cause seal faces to separate or cause bounce resulting in cracked faces and seal failure. Vibration also increases fretting under the oil seals and mechanical seals resulting in shaft damage.

Dynamic balancing minimizes stress and vibration in order to increase service life of the equipment. It is one of the most cost effective ways to provide value to industrial equipment owners.

OTP Industrial Solutions is pleased to assist equipment owners with their dynamic balancing requirements. Please contact us to discuss your balancing needs.

NET POSITIVE SUCTION HEAD (NPSH) 101

By Dan R. Benjamin

Anyone who has studied a pump performance curve has seen several components on the graph below. There is usually a vertical axis that depicts pressures and a horizontal axis that depicts flow rates. Additional components include efficiency, horsepower and impeller diameters. There may also be a curve labeled NPSH or NPSHr.

pump performance curb

NPSH = Net Positive Suction Head
NPSHr = required
NPSHa = available

Every pump installation has a certain amount of NPSHa and every pump has a certain amount of NPSHr at each given performance point. Simply put, pumps need positive pressure on the suction side in order to “push” the liquid being pumped into the suction of the pump. That push comes from the sum of all the positive influences on the liquid to be pumped at the source. These positive influences include atmospheric pressure and the actual height of the liquid above the pump suction. Additional factors to consider include both temperature and characteristics of the liquid.

NPSH PROBLEMS

Pump performance problems can occur if NPSHa is not properly considered when selecting a pump for a given application. The NPSHa has to be calculated and compared to the NPSHr, as supplied by the pump manufacturer.

If there is not enough NPSHa, numerically expressed as a number greater than the NPSHr, you can expect the pump to cavitate which shortens its useful life and limits its performance. If the pump you have selected cannot be reconsidered, there are several solutions. The feasibility of these solutions can only be considered when evaluating specific installations.

POSSIBLE SOLUTIONS

  • Raise the liquid level on the suction side which increases the vertical height
  • Lower the temperature of the liquid being pumped (vapor pressure)
  • Physically lower the pump
  • Physically raise the tank on the suction side
  • Increase the diameter of the suction piping

QUESTIONS?

Learn more about NPSH and how to improve the performance of your pumps by calling your OTP Industrial Solutions Sales Engineer. Our experts have answers to all your pump questions.

TRIPLE R OIL CLEANING SYSTEMS: A COMPLETE SOLUTION

By Shane Takaki – Triple R America

THE ENGINEER’S COMPROMISE

Ask an engineer to design anything and the response will typically be, “You can have good, you can have fast, you can have cheap; pick two.”

When faced with the challenge of cleaning oil, Triple R’s engineers chose a design that’s good and economical, compromising on speed. Triple R’s bypass oil cleaning systems are designed to take a slow trickle of oil through a 114 mm medium, delivering perfectly clean oil: good and economical. In fact, with Triple R oil cleaning systems your oil can become cleaner than new.

There will be those who say that they already have filtration on their system and don’t need any more. The vast majority are owners of spin on, inline filters. The engineers of this type of filter made a different choice: they chose fast and cheap. These filters take 100% of the flow, so they do their work in one pass. The compromise is that it is impossible to clean efficiently so fast.

Take note that many of these inline filters come with incredible micron ratings. A rating of 1 micron absolute means that in a test environment, in a single pass, the largest particle that can pass through the filter is 1 micron. Note also that ISO has moved away from such tests because they do not reflect actual usage. To the end user, test results from a single pass are largely useless, so ISO developed beta testing, a multi-pass test that better reflects actual usage conditions. This is why Triple R espouses beta testing; it provides the user with information that is relevant to the customer’s needs.

INSTALLATION BY APPLICATION

There are three ways that Triple R oil cleaning systems can be installed. All are a kidney loop, returning to tank, but the oil cleaning systems differ to fit the applications. The most common installation is from a high pressure line in a hydraulics application. Triple R BU series housing tees off a working pressure line, often immediately after the pump, and returns to tank. This system incorporates a pressure compensated flow control valve to reduce the flow to a trickle. (An integrated check valve ensures that the pressure inside the housing stays within spec.) The oil flows slowly over the top of the filter element, down through 114 mm of medium to the bottom of the housing, where it returns to tank.

The second installation is in a low pressure system, such as engine lubrication. In an engine, oil from the pump goes through the oil gallery, is fed into the Triple R AL series housing, and again flows slowly from the top of the filter element down through 114 mm of medium to the bottom, where it returns to tank. This system does not require a flow control valve or a check valve and so is more economical.

Finally, we have systems that install completely offline, drawing from tank and returning to tank. These systems have their own pump and motor, making them completely independent of the equipment while cleaning the oil thoroughly and completely. Contamination never sleeps, and Triple R’s SE series of offline systems doesn’t either.

COMPREHENSIVE PRODUCT LINE

From its simple beginnings, the Triple R product line has grown to be able to accommodate all kinds of oil in a wide variety of applications. Our M series filter elements are commonly used in (high pressure) hydraulics applications where filtration requirements are very high. Our E series filter elements are recommended for (low pressure) engine applications where longer maintenance intervals and extending oil life are priorities. In applications where it is impractical to use system pressure to feed the oil cleaning system, Triple R offers a system complete with its own pump and motor.

Triple R complements our filtration technology with product families of vacuum dehydrators, centrifuges, magnet conveyors, oil separators, water separators and the Quicktron (an air bubble remover). With this complete product line, Triple R is able to meet all of your oil cleaning needs.

Contact your local authorized distributor, OTP Industrial Solutions, for more information on Triple R products and the solutions they can provide to you.