Friday, November 11, 2011


Washington Island, Wisconsin -

Back on September 17, I had posted information about a piece of old machinery, thought to be associated with a steam vessel that might have repowered at Richter's Point on Detroit Island.

That location is where it was uncovered in sandy soil by Dr. Rod Johnson, property owner, who then offered it to the Jackson Harbor Maritime Museum.   It would be, judging from old photos, at least 100 years old, as that was when this tip of Detroit Island directly across from the present island ferry docks was active with fishermen and their craft.

We could only guess at how the heavy cast iron piece was used, and so I asked if readers had any ideas.

Responses came from several people, each with experience and background in marine matters (well, one is a lawyer with an avid interest in all things maritime, old and new).

David Foss, engineer for the Interlake fleet and retired Senior Chief Engineer, U.S. Navy, identified it as a steam pump, and went further to guess it might have been removed from the L.P. Hill.   I suspect David might have had a photo that identified the Hill moored at the Detroit Island dock.  There are several old Detroit Island photos (copy machine copies, actually) I have that show many fishing craft moored to the Richter Point fishing docks, and in one, a very large steam tug.  Other, much larger, cast iron parts are half-buried beneath the existing dock, too heavy and awkward to move.

Lew Clarke, retired attorney with a great deal of time on the water as a kid riding along with Chris Anderson on the Wisconsin, did recognize it as a pump, and he recited some working pressures that passed me by.  Lew did not think such a piece was ever used as a boiler feed water pump, however, and for that we will give him only a B+.

Eric Bonow, also a Great Lakes sailor and mate on Interlake ships, looked up some helpful information and sent along copies from that literature describing the type of pump found on Detroit Island.  Most surprising is that this design is apparently so timeless in marine applications (and elsewhere, too) that nearly the identical pump to the one now at the Jackson Harbor museum can be ordered from the internet.  According to a Gardner Denver site, this Duplex Steam Pump can be air, steam or gas driven, and has application for boiler feed, oil service, water service, or general service, with pistons and valves of different materials depending upon specific intended use.

The topmost illustration was copied by Eric from the Audel Power Plant Engineers Guide c. 1945, 1948.

From pages of a book titled Practical Marine Engineering, c. 1918, also sent by Eric, we learn more about this type of pump and why it was versatile in steam application:


In early marine practice the flywheel pump was a favorite type, and was used for all ordinary purposes where an independent pump was required, as for boiler feed, fire purposes, or for general purposes on shipboard.  This pump consisted essentially of horizontal steam and water cylinders with the piston and plunger on a common rod and moving together.  Attached to the rod was a crosshead with connecting rod leading to a crank and shaft carrying a fly wheel.  The fly wheel served to carry the pump past the dead points, and the shaft served to carry an eccentric which actuated a simple slide valve on the steam cylinder.
  This type of pump, however, has almost entirely disappeared from modern practice, its place being taken by the direct acting pump with its greater compactness of form and better adaptation to the conditions of service.
  Now consider briefly the essential features of this type of pump, with a few examples drawn from modern practice.
  As illustrated in Fig. 325, the pump is horizontal and consists of two cylinders, one for steam and one for water, carried on a common piston rod.  The steam end is operated by means of a suitable valve gear as a simple reciprocating engine, and this communicates the same movement to the pump plunger or piston.  Each end of the water cylinder is provided with both inflow and outflow valves, as shown, and thus the pump becomes double acting --- that is delivering on each stroke alternately from one end and then the other.
  For operating the steam ends of pumps of this type, a great variety of ingenious valve gears have been devised.
  The need of especial devices arises from the fact that there is no rotating part and no chance to use an eccentric, and that the valve cannot be operated directly from the main piston rod.  Where it is thus required that a single set of principal moving parts be self operating, the valve gear usually consists of the following features:   (listed) ..."

Complete copies of the literature provided by Eric were passed along to Kathleen Morris, Director for the Jackson Harbor museum.

There you have it:  more than you ever cared to know about this steam pump, a design for the ages!
  -  Dick Purinton

1 comment:

Bill Tobey said...

That IS interesting, Dick. YouTube has a bunch of short duplex steam pump videos. Here's one .....