[TheForge] Upside down Press - oh what a tangled web we weave

[Bruce Freeman]

I can see how flammability of hydraulic fluid could be a concern, but why not go with a non-flammable hydraulic fluid in that case.  See below:
Bruce
NJ

from: www.uniqema.com/lubricants/lit/lub4/page5.html 

4-5. Types of Hydraulic Fluids
a. Petroleum. Petroleum-based oils are the most commonly used stock for hydraulic applications
where there is no danger of fire, no possibility of leakage that may cause contamination of other products,
no wide temperature fluctuations, and no environmental impact.
b. Fire resistant. In applications where fire hazards or environmental pollution are a concern, waterbased
or aqueous fluids offer distinct advantages. The fluids consist of water-glycols and water-in-oil
fluids with emulsifiers, stabilizers, and additives. Due to their lower lubricity, piston pumps used with
these fluids should be limited to 20,670 kPa (3000 lb/sq in.) Furthermore, vane pumps should not be used
with water-based fluid unless they are specifically designed to use such fluids.
(1) Water-glycol. Water-glycol fluids contain from 35 to 60 percent water to provide the fire
resistance, plus a glycol antifreeze such as ethylene, diethylene, or propylene which is nontoxic and
biodegradable, and a thickener such as polyglycol to provide the required viscosity. These fluids also
provide all the important additives such as antiwear, foam, rust, and corrosion inhibitors. Operating
temperatures for water-glycol fluids should be maintained below 49 EC (120 EF) to prevent evaporation
and deterioration of the fluid. To prevent separation of fluid phases or adverse effects on the fluid
additives, the minimum temperature should not drop below 0 C (32 F). 0 0
(a) Viscosity, pH, and water hardness monitoring are very important in water-glycol systems. If water
is lost to evaporation, the fluid viscosity, friction, and operating temperature of the fluid will increase. The
end result is sluggish operation of the hydraulic system and increased power consumption. If fluid
viscosity is permitted to drop due to excessive water, internal leakage at actuators will increase and cause
sluggish operation. A thin fluid is also more prone to turbulent flow which will increase the potential for
erosion of system components.
(b) Under normal use, the fluid pH can be expected to drop due to water evaporation, heat, and loss of
corrosion inhibitors. The fluid pH should be slightly alkaline (i.e., above pH8) to prevent rust. However,
because of their volatility and toxicity, handling of the amine additives that stabilize the pH is not
recommended. Therefore, these essential additives are not usually replenished. Fluids with pH levels that
drop below 8 should be removed and properly discarded.
(c) Make-up water added to the system must be distilled or soft deionized. The calcium and
magnesium present in potable water will react with lubricant additives causing them to floc or come out of
solution and compromise the fluid's performance. When this condition occurs the fluid is permanently
damaged and should be replaced. To prolong the fluid and component life, water added to the system
should have a maximum hardness of 5 parts per million (ppm).
(2) Water-oil emulsions
(a) Oil-in-water. These fluids consist of very small oil droplets dispersed in a continuous water phase.
These fluids have low viscosities, excellent fire-resistance, and good cooling capability due to the large
proportion of water. Additives must be used to improve their inherently poor lubricity and to protect
against rust.
(b) Water-in-oil. The water content of water-in-oil fluids may be approximately 40 percent. These
fluids consist of very small water droplets dispersed in a continuous oil phase. The oil phase provides good
to excellent lubricity while the water content provides the desired level of fire-resistance and enhances the
fluid cooling capability. Emulsifiers are added to improve stability. Additives are included to minimize
rust and to improve lubricity as necessary. These fluids are compatible with most seals and metals
common to hydraulic fluid applications. The operating temperature of water-in-oil fluids must be kept low
to prevent evaporation and oxidation. The proportion of oil and water must be monitored to ensure that the
proper viscosity is maintained especially when adding water or concentrated solutions to the fluid to make
up for evaporation. To prevent phase separation, the fluid should be protected from repeated cycles of
freezing and thawing.
(c) Synthetic fire-resistant fluids. Three types of synthetic fire-resistant fluids are manufactured:
phosphate esters, chlorinated (halogenated) hydrocarbons, and synthetic base (a mixture of these two).
These fluids do not contain water or volatile materials, and they provide satisfactory operation at high
temperatures without loss of essential elements (in contrast to water-based fluids). The fluids are also
suitable for high-pressure applications. Synthetic fluids have a low viscosity index, anywhere from 80 to -
400, so their use should be restricted to relatively constant operating temperatures. When required to
operate at low temperatures, these fluids may require auxiliary heating. Synthetic fluids also have high
specific gravities so pump inlet conditions must be carefully selected to prevent cavitation. Phosphate
esters have flash points above 204 EC (400 EF) and auto-ignition temperatures above 483 EC (900 EF),
making these fluids less likely to ignite and sustain burning. Halogenated hydrocarbon fluids are inert,
odorless, nonflammable, noncorrosive, and have low toxicity. Seal compatibility is very important when
using synthetic fluids. Most commonly used seals such as Nitrile (Buna) and Neoprene are not compatible
with these fluids.

>>> davesmucker at hotmail.com 8/26/2005 2:31:41 PM >>>
I think "Chuck's Design" is the safest one out there.  Especially getting 
all of the hydraulic below the hot metal where it can be shielded.  I don't 
know of a blacksmith killed or badly burn with a press accident but it may 
very well happen.  I know of several very bad industrial accidents of this 
type.  Hot metal and a spray of hydraulic oil do not go well together.

By the way -- SACK of Germany has made some very large industrial forging 
press of this design.  Union Electric Steel and Forging in Pittsburgh has 
one.  SACK is now part of the SMS Demag AG group.

Dave