Hi all, still new to the ultrasound world and I have been addressed by one of our techs with a good question and was wondering if any one could provide some experienced insight. Under normal conditions there is usually some change in dB's when adding Grease, up or down! We've recently come across a small groupe of Vacuum pumps that frequently come in and out of load. When the tech had come back from this particular route he said there had been No change in dB levels after adding 10 pmps at one gram per pump and at what point do you stop adding grease. Any help is greatly appreciated

JD,

Have you calculated the volume for the bearings in question? I have some vacuum pumps that require 8 ounces of grease for proper lubrication.

Ken Culverson

In addition to Ken's comment, I would add that the background ultrasound level on bearing housings can vary with load on machines like vacuum pumps, rotory positive displacement blowers and pumps. The backgound ultrasound level on some types of machines may not be low enough to detect the reduction of friction and impacting associated with lubrication.

Walt

JD,

We have a U/E grease caddy that was bought for our department earlier in the year. We have so far not thought it was as effective as was advertised. I have much better luck using our ultra sonic gun and greasing but as mentioned earlier we watch our grease amounts closley.DB levels seem to be more consistant on the ultra sound gun than watching the light bar level on the grease caddy.

Regards, Dave Dane

Sometimes using the ultrasonic gun (your Ultraprobe and Contact Probe) may sound better especially if you are using the UP9000. The sound quality of the UP2000 or UP9000 as well as the SDT 170 is much better than using the less sensitive Grease Caddy contact. In the past I have written about using the Ultraprobe 2000 and contact probe for lubricating bearings. Depending upon which unit you have (2000 or 9000) set the sensitivity to a mid-range. Shoot HALF-STROKE of the grease gun or equivalent shot if using an air assist gun. After shooting the initial shot of grease watch the needle (UE2000) or decibels (UE9000), if the sound level or db's goes down shoot another half-stroke, repeat until the sound level starts to go upward. When this happens stop give it several seconds (15-30 sec.'s depending upon ambient temp, longer for colder areas) to come back to the previous reading or less. If it does not after 15-30 seconds stop lubricating. Sometimes you and I cannot pick-up the subtle differences when it occurs, sometimes due to the machinery background noise you will not hear a difference. Again the analog or digital display sound level (db's) will help you see the difference.
The SDT-170 has an Acoustic Lubricator Adaptor (I designed and made for SDT). It is now made of solid metal body good attenuation and is coupled with the SDT-170 contact probe. Here you have the sensitivity of the contact probe and the ultrasonic unit, coupled to the acoustic adaptor which mates to the zurk fitting. The SDT procedure I would suggest would be to take either the SDT-150 or SDT-170 and (with or without the adaptor) touch the grease fitting or a point on the motor and note the decibel reading on the display. Shoot HALF-STROKE of the grease gun or equivalent shot if using an air assist gun. After shooting the initial shot of grease watch the decibels (dBUv or db's), if the sound level or db's goes down shoot another half-stroke, repeat until the sound level starts to go upward. When this happens stop give it several seconds (15-30 sec.'s depending upon ambient temp, longer for colder areas) to come back to the previous reading or less. If it does not after 15-30 seconds stop lubricating. Sometimes you and I cannot pick-up the subtle differences when it occurs, sometimes due to the machinery background noise you will not hear a difference. Again the digital display and sound level (db's) will help you see the difference.
Good Luck....Keep up the good work.

P.S. Have you ever been called by the company that overhauls your motors and were told, "If you guys would quit over-lubricating your motors, we would not have to overhaul your motors."? Over-Lubrication kills motors!

Hello JD,
one of the key points I make in my teaching in this subject is to make absolutely sure that there is actually something which can be greased behind that fitting. Manufacturers of machines and maintenance people frequently leave grease fittings in place when the bearing has been changed or the grease path is not connected, or even in one case I found connected the wrong way round.
Any of these possible options would also explain your technicians difficulty.
I'm sorry if this sounds stupid, but it has caught me out before and I believe that a good expert is someone who has made all the mistakes possible in a very narrow field

Thanks Tom...Absolutely, I have seen this before several times. It happens more times then is reported. I was at one facility not too long ago and the tech's were trying to force grease into a sealed bearing. In that case you could tell in a couple of pumps as the grease kept streaming out along side the lube fitting. A zurks fitting was screwed in place, the repair facility just screwed-up.

Hi all, just wanted to say thanks to you all for your time and feedback.

ddane, our thoughts are mutual!

Jim, That is exactly the phone call I would like to avoid.

Tom, I'm going to visit repair facility and I will be sure to discuss what information is on and what needs to be on the reports of our rebuilt motors.

Thanks Again

PS: Would Frequency have any bearing in an instance like this?