[TheForge] heavy metal math/c frame press

[Andy Vida]

"David E. Smucker" wrote:

> In 30 plus years I have seen one pump blow up... No fire no or other
> damage just messy.

	Hydraulic oil is a non-compressible fluid, as is water.
	This means that zero energy is stored in its mass as
	it comes under pressure.  The only stored energy in
	the hydraulic system will be located in the conduits
	as they expand under load.  These are comparatively
	very rigid, therefore energy buildup in them is small
	in terms of volume.

	Once a line fails the pressure falls to zero virtually
	instantaneously. The capacity of the pump to maintain
	pressure across a drop (the point of failure) is a
	direct function of its volume output.  These pumps are
	by definition low volume/high pressure affairs, therefore
	their ability to maintain pressure across that drop is
	basically nonexistent.

	Also consider that the point of failure will continue to
	expand if a high load continues to be applied to it,
	requiring ever higher volume flow to maintain pressure.
	This constitutes in inherent failsafe system.
	
	If one's hand were to be situated directly on the point
	of failure of a 10KPSI line, I would say there was a 
	definite chance for significant injury via poisoning
	(hydraulic fluids are toxic).  Otherwise, the pressure
	drop is so rapid that no significant danger is posed by 
	the mechanical action of the fluid.  Shrapnel from a 
	failing hard line is another story, but lines are designed
	specifically not to fail in that fashion.

	-Andy