07252017Tue
Last updateTue, 25 Jul 2017 1pm

i

How to Choose the Best Rapid Prototyping Method

How to Choose the Best Rapid Prototyping Method

As new products are designed, including ...

Monitoring Valve Health via the Internet

Monitoring Valve Health via the Internet

Most valve end users are already using s...

Valves in Oxygen Service

Valves in Oxygen Service

In his presentation at VMA’s 2017 ...

Thermal Spray Coating

Thermal Spray Coating

Q: What are the pros and cons of us...

Subscribe SUM17

FREE SUBSCRIPTION*

•  Print magazine
•  Digital magazine
•  VALVE eNews
Read the latest issue

*to qualified valve professionals in the U.S./Canada

The Weekly Report

New Products

  • ja-news-2
  • ja-news-3

Industry Headlines

IHS Market PMI Index Reached Four-Month High in July

Tuesday, 25 July 2017  |  Chris Guy

July data revealed a further acceleration in business activity growth across the U.S. private sector. At 54.2, up from 53.9 in June, the seasonally ad...

Readmore

Loading...
Advertisement
i

Web Only

The Actuation Selection Process

The Actuation Selection Process

Tuesday, 25 July 2017  |  Carlos Gamero

A common misconception in our industry is that actuating a valve is as simple as putting the most cost-efficient actuator on top of your valve of choi...

Readmore

Loading...

Industry Headlines

Badger Alloys Joins VMA as Associate Member

6 DAYS AGO

This week the Valve Manufacturers Association (VMA) welcomes Badger Alloys as an official associate supplier member. This is VMA’s fourth new member in 2017.

Located in the heart of Milwaukee and founded in 1966, Badger Alloys offers single source capabilities for custom castings. The company pou...

Readmore

Thermodyn Joins VMA as Associate Member

6 DAYS AGO

This week the Valve Manufacturers Association (VMA) welcomes Thermodyn Corporation as an official associate supplier member. This is VMA's third new member in 2017.

In 1979, Thermodyn began business with the dual purpose of selling A.W. Chesterton products and manufacturing high-temperature elastomers ...

Readmore

U.S. Fuel Ethanol Production Continues to Grow in 2017

19 HOURS AGO

Through the first six months of 2017, U.S. weekly ethanol production averaged 1.02 million barrels per day (b/d), an increase of 5% over the same period in 2016. On a weekly basis, U.S. ethanol production set a record of 1.06 million b/d in the week of January 27, 2017, and it has averaged near or a...

Readmore

LyondellBasell to Build the World's Largest PO/TBA Plant

3 DAYS AGO

LyondellBasell has made the final investment decision to build the world's largest propylene oxide (PO) and tertiary butyl alcohol (TBA) plant in the Houston area. The project is estimated to cost approximately $2.4 billion, representing the single-largest capital investment in the company's history...

Readmore

IHS Market PMI Index Reached Four-Month High in July

-1 DAYS AGO

July data revealed a further acceleration in business activity growth across the U.S. private sector. At 54.2, up from 53.9 in June, the seasonally adjusted IHS Markit Flash U.S. Composite PMI Output Index signaled the strongest rate of expansion since January.

The pickup in business activity growth ...

Readmore

IMF Lowers 2017 Growth Forecast for U.S.

20 HOURS AGO

The growth forecast in the United States has been revised down from 2.3% to 2.1% in 2017 and from 2.5% to 2.1% in 2018, according to the IMF’s World Economic Outlook. While the markdown in the 2017 forecast reflects in part the weak growth outturn in the first quarter of the year, the major fa...

Readmore

Grease for Motor Actuator Maintenance

Maintaining the right amount of grease inside motor actuators that use grease for lubrication is a vital part of valve maintenance, and can save time and money by preventing problems before they happen. Inadequate lubrication is often the culprit in a malfunctioning motor actuator, and understanding how to effectively manage grease in motor actuators can be a simple way to keep costs down and to keep actuators out of the repair shop.

Motor actuators must have the correct amount and type of grease in the gear case to provide for trouble-free operation.

 

Getting Inside
The first step is getting inside the actuator. Actuators have from two to four grease plugs to allow adding and checking the level of grease. The quality, quantity, and consistency of the grease in the actuator should initially be checked every 18 months, then at a frequency derived from the results. This inspection must be accomplished through these grease plugs.

Motor actuators are built to operate on the partial immersion principle. What matters is whether or not the "worm" is totally immersed in grease. This is to ensure that the efficiency of the worm/worm gear set is operating at its highest level, because this gear set is the most inefficient gear set in the actuator, operating at about 20% to 25%.

Due to the heat of the sun or system operation, the gear box is pressurized, which is why just filling up the gear box with grease causes the grease to push through the seals and into the motor windings and/or into the limit switch compartment.

To determine the correct amount of grease to add to a gear box, perform an inspection by using one of the many "fill and drain" plugs to ensure the worm is totally immersed in grease. When the actuator is mounted in a different orientation, the amount of grease needed to totally immerse the worm will change.

If your actuator is disassembled for repairs or rebuilding, these grease plugs should all be removed, cleaned, and reinstalled. Sometimes these plugs will be corroded in the housing and must be drilled out. Due to the metal chips that will fall into the grease, don't drill them out during operation. Instead, remove them during the rebuild when the inside is exposed.

The drive sleeve in an actuator extends through the housing on both the bottom and top sides. A seal is used to prevent leakage of grease at this penetration. The lower drive sleeve is held in place by a seal retainer, which is installed and removed, from the bottom of the actuator. This seal retainer is held in place by screws, bolts, or just a press fit on different sizes of actuators.

When the actuator is disassembled for repair or rebuild, this seal retainer does not need to be removed to fish out the seal and replace it. However, it should be removed to allow the rebuilt drive sleeve to be installed first. If the seal is installed first, and then the drive sleeve, there is no way to ensure that the seal is not nicked or rolled during the drive sleeve installation.

Grease in the main gear box will not flow into the clutch housing compartment of the actuator, so this compartment must also have grease added to cover the motor pinion/worm shaft clutch gear set. Fill this area just enough to cover the gear set-not too full.

The actuator can be mounted in any position since it has a totally sealed gear case. However, mounting positions that would cause vulnerable areas of the actuator (e.g., motor and limit switch compartment) to be saturated with grease in the event of a seal failure are not recommended.

The Right Grease
Use only the correct type when adding grease to your actuators. This means the grease must:

 

  • contain an "EP" additive
  • be suitable for the temperature range needed
  • be water and heat resistant and non-separating
  • not create more than 8% swell in Buna N or Viton seals
  • not contain any grit, abrasive, or fillers
  • not slump-preferred NLGI grade 0 to 1
  • not be corrosive to steel gears, ball, or roller bearings
  • have a dropping point above 316° F for temperature ranges of -20° F to 150° F.

In addition to the above, keep in mind that grease is made up of a filler (soap) and oil. Different types of fillers are used and not all types will mix well with each other. If you are going to add grease, use the same type of grease in the gearbox or ensure the new grease is compatible.

Regularly checking the level and quality of grease inside motor actuators will provide results that speak for themselves. Quite literally, proper lubrication makes a motor actuator function more smoothly, and keeps it lasting longer and working at maximum efficiency at very little cost.

  • Latest Post

  • Popular

  • Links

  • Events

Advertisement

Looking for a career in the Valve Industry?

ValveCareers Horiz

To learn more, watch the videos below or visit ValveCareers.com a special initiative of the Valve Manufacturers Association