Engine Cooling Tank First Patent for D.C. Stover
When Stover Manufacturing & Engine Co. founder Daniel C.
Stover died in 1908, he left behind a legacy of invention and innovation, with
more than 100 patents to his name. The various companies — there were 10 all
told — established by D.C. Stover between 1862 and 1916 manufactured a broad
spectrum of agricultural and consumer goods.
Most of us associate Stover with gas engines, the first of
which were produced experimentally as early as 1895, with full commercial
production commencing by 1902. It’s known that Stover acquired many of the
patents needed for engine production, but he was awarded several patents for
his own work, including his very first, Patent No. 722,767, awarded March 17,
1903, “Apparatus for Cooling the Cylinders of Gasolene-Engines.”
As can be seen in the accompanying patent drawing, Stover’s
design for an engine cooling tank with control valves was more evolutionary
than revolutionary, perhaps reflecting his common sense approach to products.
The patent focused on Stover’s use of a pair of coupled valves that could be
opened and closed as needed to regulate the flow of cooling water from a
cooling tank to a stationary engine and back.
Extremely simple in design, and by extension execution,
Stover’s scheme featured little more than a system of levers and valves, the
levers opening and closing cut-off valves at the top and bottom of a cooling
tank. Although it’s not stated in the patent, it can be assumed from the lack
of any pumping apparatus in his patent drawings that Stover was operating under
the thermosiphon principle, where convection causes the heated water to rise,
siphoning cooler water behind it.
In Stover’s design, the valves and actuating levers are all
contained within the cooling tank. This has two obvious advantages. One would
be protecting the mechanisms inside the cooling tank where, it would seem, they
would be less likely to be inadvertently moved or damaged. The other, and one
which Stover specifically noted in his application, is the advantage of using
water pressure to help seal the valves on their seats. Located outside the
tank, the valves would be holding back against water pressure. But located
inside the tank, water pressure would help to hold the valve plates against
their seats, ensuring a better seal.
One aspect that does seem curious, and is not addressed in
the patent description, is the location of the main actuating lever inside the
tank, accessible only by opening the top of the cooling tank. It would seem
desirable for the lever to protrude from the top so the operator would not have
to be in direct proximity to hot water. Then again, practical experience
suggests it would be rare for the water to reach scalding temperatures, and
this was, after all, a very practical design.
Know of an interesting
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