Seal Repair 1

[YoYo2000]

Hi,

What does it mean to have a phonographic finish on the seal face?

And why does this happen?

Thanks in advance for help.

 

[JJPellin]

A phonographic finish or the phenomenon of phonographing are descriptions of circumferential scratches or grooves on a face. If you are referring to a mechanical seal face, phonographing would suggest abrasive particles got between the faces and scratched the surfaces as the seal was rotating. If you are referring to a static sealing surface (a gasket surface) a phonographic finish might be deliberately applied to provide better sealing against the gasket. This is most common on piping flange faces used with spiral wound gaskets.

Johnny Pellin

 

[YoYo2000]

Does the seal face go shiny?? The customer said it was phonographic..i dont see any scratches but he area of contact between the washer and the seat, on the SiC seat, is very shiny? Why is that so?

 

[JJPellin]

There are two common finishes applied to mechanical seal faces. They are mirror finish and matte finish. A mirror finish is most common in my industry because it allows the face flatness to be evaluated using a monochromatic light source and a flat reference (optical flat). A matte finish can have some advantages in terms of film thickness of the running seal. For some of our seals, we require that a mirror finish is applied, the face flatness is evaluated using an optical flat and then the matte finish is applied.

I have never heard of anyone deliberately applying a phonographic finish to a mechanical seal face. Perhaps they intended to say matte or mirror. If the face is very shiny, it sounds like a mirror finish.

Johnny Pellin

 

[JJPellin]

If you are looking at a seal face that has failed in service, the wear track may appear to be shiny. But, under the appropriate magnification, there could be phonographing damage in the form of fine circumferential scratches. These might not be clearly visible with the naked eye.

Johnny Pellin

 

[flexibox]

If you have a shiny face you probably had dry running!

 

[YoYo2000]

I thought it meant there were some solid particles that got in between faces and scratched them..flexibox..why with dry running does it produce the shiny face? What is the logic behind it?

 

[flexibox]

When you have solids, the particles imbed into the soft surface and act as a grinding wheel in operation. When you say phonographic finish, what can happen is that as the faces grind into each other, the fluid film is lost and you get the shine on the faces. Sometimes you see blueing due to heat generation. So if you have a gramaphone finish due to abrasive particles then it is likely to have lost fluid film resulting in a shine on the faces.

Perhaps you should give us the full duty conditions and perhaps add a photo of the faces. Is this water application?

 

[Compositepro]

A phonographic finish is a continuous spiral groove that can accomplish pumping of the seal fluid due to seal rotation. It allows for better fluid lubrication of the seal faces while reducing leakage.