Sign up Calendar Latest Topics Donate
 
 
 


Reply
  Author   Comment   Page 2 of 2      Prev   1   2
RustyCas

Avatar / Picture

Admin
Registered:
Posts: 1,810
Reply with quote  #16 
Infrared?  You can get the Flir C2 Pocket Cam for $500 if you don't have one already.
__________________
"The trend is your friend"
Danny Harvey

Sr. Member / Moderator / Supporter
Registered:
Posts: 1,402
Reply with quote  #17 
Dave,

Don't forget your strobe.
RRS_Dave

Sr. Member / Supporter
Registered:
Posts: 216
Reply with quote  #18 

Yes, I thought of the strobe, but under their lighting, I'm not sure what it will do. I'm going to take it anyway.
Hadn't thought of infrared, since I'm not sure the "marshmallows" can generate any frictin on itself, however, I won't rule anything out since I don't know anything anyway [wink]
thanks,

D

RRS_Dave

Sr. Member / Supporter
Registered:
Posts: 216
Reply with quote  #19 
Well, here is the deal. The feeders that I thought I knew something about, turns out I knew nothing.
Here are the feeders that they wanted me to look at.  

http://www.meyer-industries.com/pdf/vibratoryconveyor/VFII-Multi%20Purpose%20Conveyors.pdf

I have some pictures I will post in a couple days when I get a break. Basically, as far as I can tell, there is a frame that has an exciter mounted to it (some have two, depending on size of conveyor) with many groups of 3 "springs" (look like absorbers) fastened to the frame and to a conveyor on the other end (I saw some with conveyor above frame and some with conveyor below frame, and 1 that had the conveyor running through the middle of the frame.). In no instances is the motor or the electromagnetic drive coil (on a small conveyor with 4 absorbers on each side) powering the conveyor directly. I felt of the frame with the drive motor attached and felt very little vibration. They drives were in the 2 HP range running at 1785 and tunable from around 56 hz to 62 hz. You can also move the eccentrics on the ones I was directly looking at to achieve a higher amplitude to run more (deeper) product through. Seems the conveyors were weak at the attaching point of the fiber springs, and they would crack the stainless which warranted repairs.
The "marshmallows" they were concerned about were the isolators that were between the frame and the floor. They changed these out after 5 years, but no one seems to know why. I can only guess that the vibration was being felt in the catwalks, and the conveyors were losing their "umph" (this was about the time they started upping the frequency and changing the eccentrics to a larger throw). After seeing the setup, and understanding what they wanted to check, I could do a simple vertical vibes check below the isolators to ascertain some level of vibes at the frequency being used, and watch for that to trend up. How high is too high would be a subjective measure the first time or two, but then I'm now so sure it would be cost effective seeing the MTBF was around 5 years or maybe more.

Has anyone else ran into these in the food industry? If so, what has been your experience?
I have a video I took of the thing working...... a bunch of absorbers doing work. Hmmmmmm


D
Walt Strong

Sr. Member
Registered:
Posts: 889
Reply with quote  #20 
Dave,
I worked on a vibratory bowl feeder and a razor blade manufacturing plant. I worked on a linear vibratory conveyor at a small powerplant that burned tires, and the conveyor transferred whole tires.

If you want to learn more about these devices then search: vibratory feeder natural frequency tuning

You should see this reference:

Assembly Automation and Product Design
By Geoffrey Boothroyd

See Chapter 3

Pasted from <https://books.google.com/books?id=XFtgaNFzMHQC&pg=PA47&lpg=PA47&dq=vibratory+feeder+natural+frequency+tuning&source=bl&ots=2kedRz5hdU&sig=5kBuILLtgfrfcHWVtVtOCa0qLjM&hl=en&sa=X&ved=0ahUKEwjzyoyDqsLTAhWBQCYKHalHCOgQ6AEIYTAH>

The structural natural frequency of the feeder is often set slightly above the driving frequency so that the feed rate is less sensitive to load on the conveyor/feeder. Broken springs or deterioration of the isolation mounts can change the natural frequency and adversely affect feed rate or change in vibrations transmitted other structures.

Walt

Danny Harvey

Sr. Member / Moderator / Supporter
Registered:
Posts: 1,402
Reply with quote  #21 
Dave,

I wouldn't be surprised to find that they overtightened the "marshmallows".

I've only worked on this type of device once and it was a spiral feeder that conveyed pellets vertically. 

I don't recall what the desired phase relationships were but I did cross channel across the motors (eccentrics on both ends) and between the two drives.

I'm not sure if I have any notes but I'll look around.

I called the manufacturer and asked around until I found someone who knew what to look for.

In my case the perceived problem was not cracking at the mounts but one location where the material conveyed slower than the rest of the spiral. When the client found out what would be needed to figure out why, it became much less of a problem so we don't have a resolution.

Cracked mounts sounds like maybe the wrong springs.
RRS_Dave

Sr. Member / Supporter
Registered:
Posts: 216
Reply with quote  #22 
The isolators don't have any bolts or nuts on them to tighten them with, all the ones I was shown were just sandwiched between the resonating frame and the floor mount. I asked how big the studs were that had to be sticking up that held these isolators in place and the guy I was with didn't know. He had never seen them out, but had been told the unit had to be jacked up in order to remove the isolators. I was somewhat confused because there was no real defined "problem" that had occurred or that could be pointed to that made them want to check on these isolators. I tried to put words in their mouths about losing flow because of the isolator getting hard and passing frequency through instead of isolating it like it should, but could never get a thorough answer.
I will continue to peruse this beast, and ask others around (probably the operators or the operations engineer of this section) and see what problems they have. Maybe one of them can be attributed to these losing their isolating ability. I don't know, but with only four of them on each unit I looked at, I am thinking that if there is a problem attributed to them, I would be hard pressed to not recommending changing all four instead of trying to pinpoint one them. All of them see the same environment as the others. I wouldn't think one would go bad that the other three wouldn't be far behind.

Thanks for the link Walt. I will peruse this and become much more familiar than I am. You can take the boy out of the country, but hard to take the country out of the boy.

D
Previous Topic | Next Topic
Print
Reply

Quick Navigation:

Easily create a Forum Website with Website Toolbox.