piston pump seals 1

[ian600]

Hello ,

I am seeking clarification regarding both the extent and also the distribution of the interference between the seals on a piston pump and the metal parts . I am seeking to quantify both properties .
In my work I manufacture piston pump seals . The seals are machined from solid bar using a CNC lathe and the seal geometry is generated on a CADCAM system . Typically I refer to vees arranged in a stack .
I do service work on piston pumps and I find that the reliability engineers & reliability fitters are only able to provide samples , not drawings . The drawings of the seals are not usually available .
I am seeking to ensure that the seals which I manufacture meet the standard in these respects with the right amount of interference . I’m keen to discuss this matter with anyone who knows...

 

[micalbrch]

I think that will not work if you must guarantee the correct tolerance. When the seals are installed in the piston and the piston covers (or whatever metal parts you will find) are tightened, the seals get some primary tension (between 0.1 and 0.3 mm as an example). This tension is important for the correct sealing of the seals. That means the dimensions of the single seals are different from the dimensions after installation. Furthermore you need to know the correct dimension of the counter part, too. This is usually the cylinder liner. They are machined inside and as long as you do not know the tolerance there, you will never know what the correct dimension shall be.

Perhaps somebody here has a more positive advice.