O-rings Failing?

[danhelgerson]

If you have a problem with static seals leaking over time, you may want to look at the energy loss in the system.

I had a discussion with a plant engineer in which he told me that O-rings leak but NPT fittings do not. On further examination, it was learned that there is a great amount of heat being generated by the poor design of the hydraulic system. A large heat exchanger masks the problem. The reservoir temperature is at 120° F. However, the oil is brown from being “burnt”. The heat is being generated within the valve manifold as the fluid goes from high pressure to low pressure across the relief valve. This heat is sufficient to continue the cure of the O-rings which become brittle and flat. The O-rings loose their ability to seal and the valves continually weep at the manifold connection.


Dan Helgerson CFPS, AFPI, AJPP

http://www.cfpsos.com

 

[budt]

Dan wrote;

"it was learned that there is a great amount of heat being generated by the poor design of the hydraulic system."

Until there are trained persons in plant that can design and maintain Fluid Power systems the above diagnosis will be normal.

Until industry stops depending on Fluid Power salesman or distributor to design circuits much of the the equipment using Fluid Power will be below par and over heating is just one of the problems.

Of course we could use Viton "O" Rings, at 4 times the cost, to stop the leaks but it wouldn't help the brown smelly oil situation.


Bud Trinkel CFPE
HYDRA-PNEU CONSULTING, INC.
fluidpower1 @ hotmail.com

http://www.fluidpower1.us

 

[danhelgerson]

Thanks Bud.
It will also help when industry learns the value of having trained people on their own staff to protect them from bad design. The company mentioned in my note is relatively small but it can be demonstrated that they have lost $2,000,000 over the last 10 years in wasted energy because of poorly designed and poorly understood hydraulic systems. We have not even begun to address the losses in the pneumatic systems. All of this could have been avoided with a knowledgeable fluid power person on staff or if, as you imply, a competent engineer had been invited in to oversee or upgrade the designs.

One of the ironies is that the company thinks it cannot afford to have a trained fluid power person on staff. Wasting $2-$300,000/year in energy costs seems to illustrate the fact that ignorance is more expensive than knowledge.

Dan Helgerson CFPS, AFPI, AJPP

http://www.cfpsos.com