Improvement relating to the Tubes of Water-tube Steam Generators.
Year: 1899

page_text: Date of Application, 18th July, 1899-Accepted, 2nd Sept., 1899
COMPLETE SPECIFICATION.
Improvement relating to the Tubes of Water-tube Steam Generators.
I, GUSTAV DÜRR, Mechanical Engineer, of Grafenbergerchaussee 84, Düssel-
dorf, Germany, do hereby declare the nature of this invention and in what
manner the same is to be performed to be particularly described and ascertained
in and by the following statement:-
-
This invention relates to a device for closing the lower or narrow ends of
inclined water tubes commonly known as field tubes.
In the accompanying drawings, Fig. 1 is an axial section through the narrow
or lower end of a water tube embodying this invention; Figs. 2 to 5 represent
modifications.
In the case of ordinary field tubes, drawn in" at their closed ends, the
removal of mud and scale from the contracted parts has not been feasible hitherto
without difficulty, even though the tubes were inclined. Neither could those
sediments be driven out of the tubes by means of a blast, as this would have
necessitated the unscrewing of the closing devices.
These inconveniences are obviated by the arrangement shown in the accom-
panying drawings. The tubes are here reduced gradually-in fact conically--
so that the lower side of the reduced portion takes a horizontal or but slightly
inclined direction, and that the whole of the water must flow out of the
tubes when the closing device is unfastened or removed. Over the conical
ends rings are drawn at the rear of the boiler to close the flues; each tube
being, by means of such ring, supported at the rear end in the usual manner,
within the latticed or grid-like wall, or the like, u. A plate which has aper-
tures approximately corresponding to the diameter of the rings r is then mounted
on the grid-like wall w. The plate is lined with asbestos a, extending a little
beyond the edges of the said apertures, so that the asbestos is in direct contact
with the rings.
The closing or fastening device employed consists either of a screw-cap k
fitting over the reduced and screw-threaded tube-end, or of a screw-plug screwed
into an extension of the ring r.
The tube is tightly closed by the screw-cap, either at the end of the tube
against which presses a special packing disc u, or the tight joint is on the super-
posed ring r against which the cap abuts.
The edge of the cap and the ring are formed in a manner calculated to secure
a tight joint, (see Figs. 2-4).
Tightness is ensured between the screw-cap and the tube end, either by the
said cap itself, or through the medium of a washer u. Where a washer, such
as u, is employed, it may be provided with a prismatic projection or head, which
admits of its being turned, so as to ensure a tight fit. To enable the water to
be drawn off, where screw-caps are used, lateral apertures are provided in the
tubes (Fig. 2) which become free, when the cap is slightly turned backwards;
and where the packing is effected by means of washers u, apertures o are made
in the cap (Fig. 1). Where screw-plugs are used, as represented by Fig. 5, the
apertures are in either case made in the ring, so that here also, when the plug

page_text: is slightly turned back, the water or steam (as the case may be) may escape
through the said apertures o.
As shown by Fig. 5, in order to enable the steam and water to be readily
discharged outside, if necessary, a tube s may be provided, such tube being
connected with a collar t secured to the ring by a set-screw or other suitable
means.
Having now particularly described and ascertained the nature of the said
invention, and in what manner the same is to be performed, I declare that what
I claim is:
1. In water-tube steam generators having inclined tubes with conically
reduced rear ends, the combination of an inclined tube, with a supporting ring
or collar (r) mounted on the tube at or near its rear end and adapted to support
the tube in the rear-wall, a removable cover (2) provided with openings for
the supporting rings, and a screw-cap or screw-plug adapted to close the lower
end of the said tubes, substantially as described.
2. In water tube steam generators having inclined tubes with gradually
contracted rear ends, supporting rings and closing caps or screw-plugs, a water
tube having either in the side of the tube itself, or in the closing cap or in the
supporting ring an orifice o so arranged, that it serves as a water outlet, after
the closing cap or the screw-plug has been loosened or partly withdrawn, and
that it will be closed by tightening the said plug or cap, substantially as
described.
3. In water-tube steam generators having inclined tubes contracted and closed
at their rear ends, the various devices for forming a tight joint at the rear ends
of the tubes and for emptying the same, as described and illustrated by the
drawings.
Dated thi 1041 L
起 T 1
1000
FAIRFAX & WETTER,
Agents, 37 and 39, Essex Street, Strand, London.