Jensen and Co (Birkenhead)
1886 Engineering provided drawings of 'a double-cylinder non-condensing screw engine constructed by Messrs. Jensen
and Co., engineers, Birkenhead. In the section,
Fig. 3, a a are the working cylinders with their
respective pistons, b is a central chamber containing a
vertical shaft d, which is driven from the main shaft
by a pair of gun-metal mitre wheels with double
helical teeth. The upper end of this shaft is constructed in such a manner as to receive the slide with
pin e, to which both the valve rods are pivotted
direct, and which works the slide valves o o in the valve
chest c. The arrangement is such that the travel of
the valves can be varied and the point of cut-off regulated (the lead being kept constant) by shifting the
position of the pin e, this being effected by means of
the bell-crank with links and the sleeve g, actuated by
the spindle h and crossbar i, which latter is worked up
and down by the starting wheel with screw ; it will
thus be seen that the wheel above the cylinders starts,
stops, reverses the engine, and gives different grades
of expansion.
The engine illustrated has cylinders 6 in. in diameter
and is supplied with steam by a horizontal boiler 4 ft. in
diameter by 5 ft. long. It is fitted into a steam launch
45 ft. long by 9 ft. beam, built to the order of Messrs.
Scott, Sinclair, and Co., African merchants, Liverpool.
The boat obtained on trial a speed of 11 miles an hour,
and has been at work on the Gold Coast for about twelve
months. We may add that a number of engines on
this system have been manufactured (including some
high-pressure tandem compounds and compounds with
intermediate receiver), and these are working successfully in England and abroad; we hope at a future time to
give illustrations of Messrs. Jensen's compound engine.'[1]