A Method of Securing the Tubes of Steam Boilers in Tube Plates to Prevent them Becoming Overheated.
Year: 1892

page_text: Date of Application, 15th Nov., 1892
Complete Specification Left, 20th July, 1893-Accepted, 9th Sept., 1893
PROVISIONAL SPECIFICATION.
A Method of Securing the Tubes of Steam Boilers in Tube Plates to
Prevent them Becoming Overheated.
I JOHN PHILLIPS 4 Corona Road, Burnt Ash Hill Lee, S.E. Engineer do
hereby declare the nature of this invention to be as follows:-
I propose to form bosses or nipples projecting a sufficient distance on the water
side of the tube plates, so that they may be surrounded by water; these bosses or
nipples are bored, or otherwise prepared to receive the ends of the tubes; the tube
ends being secured into the bosses or nipples by any of the usual means.
Dated this 14th day of November 1892.
JOHN PHILLIPS.
COMPLETE SPECIFICATION.
A Method of Securing the Tubes of Steam Boilers in Tube Plates to
Prevent them Becoming Overheated.
I JOHN PHILLIPS 4 Corona Road, Burnt Ash Hill, Lee, S.E. Engineer 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:-
My present invention relates to forming bosses or nipples projecting a sufficient
distance on the water side of the tube plates, so that they may be surrounded by
water, these bosses or nipples are bored, or otherwise prepared to receive the ends
of the tubes; the tube ends being secured into the bosses or nipples by any of the
usual means, namely roller expanders, or drifts, also by screwing them in. To
effect this 1 form the tube plate with bosses or nipples as shewn by the drawing, of
such shape that when they are bored out, surfaces will be left, into which the tubes
are secured. In order that these bosses & tube ends may be sufficiently protected
by the surrounding water it is only necessary to make them extend a short distance
from the surface of the plate; the form given to the bosses, after boring, being
sufficient to resist the pressure arising from the tool used for expanding the tubes.
It has been found that when a straight or ordinary tube plate is alternately
heated and cooled in the process of stoking, that the holes in the tube plate become
distorted, so that the tube no longer fits the hole, and consequently leakage takes
place; more difficulty is found from the use of thick tube plates than from thin,
owing to the greater inequality of temperature between the inner and outer sides
of the plate respectively.
By my method it will be seen that a thinner plate than usual can be employed,
preferably about seven sixteenths of an inch thick, as the curved formation of the
plate produced by the projecting bosses adds materially to the strength, whilst
affording sufficient bearing surface for the tube ends; overheating is also prevented
by these bosses projecting into the water, and their form offers a less line of
resistance to the heat which strikes against the inner end of the tube and plate, to.
pass through than with the usual fat tube plates, in which the temperature at
different distances through the plate is not uniform.
The accompanying drawing illustrates my invention similar parts in all the
figs. being shewn by the same reference letters.
Fig. I. shews a sec. of tube end & plate as usually made.
Fig. II. shews a sec. of tube end & plate according to my method.
Fig. III. shews a sec. of tube plate with the boss or nipple formed by the

page_text: dies, and before being bored. The dotted lines shew the size of the hole to be
bored for reception of the tube.
My plan for forming the bosses is as follows-
Having selected a plate of mild steel, copper or other ductile material, of the
intended thickness, preferably 7 inch, small holes are drilled in the centres of the
intended positions of the tube holes, the plate is then placed under a power press,
hydraulic or other, which is fitted with a bed die having the form intended to be
given to the outside of the boss or nipple, the plunger of the press is fitted with a
die having a conical form to suit the shape of the inside of the boss; on closing
the dies the bosses will be formed.
The bosses can be pressed either singly or in any number according to the power
of the press; my method requiring the plate to be so little bent enables it to be
effected on a cold plate of suitable quality, if desired this plate could be afterwards
annealed. The bosses can also be formed by machining them from a plate of the
required thickness by the use of circular cutting tools. In some cases cast steel,
or malleable cast iron or other cast metal may be used, the tube holes being
subsequently bored, but the bosses should be formed of the same shape as when
pressed from a plate.
I am aware that prior to my invention a Patent No. 6148, A.D. 1891, has been
granted having a similar object in view. But as this is for flanges bent down at
right angles to the surface of the tube plate, and with thin plates as illustrated &
described, there would not be sufficient resistance to the expanding action of the
tubing tool, to secure a perfect joint between the tube end and the flange on the
tube plate.
This plan I disclaim, my method allows the use of thicker plates, as the plate
only requires to be depressed sufficiently to form the intended bosses or nipples, at
the same time the angular distance through the bosses when bored out is sufficiently
long to support the ends of the tubes; a larger space than usual is not required
between the tubes, and the form given to the bosses strengthens them to resist the
pressure arising when expanding the ends of the tubes into the holes bored in
the bosses.
Although inch steel plates are preferably used other thicknesses can be
adopted, but the bosses should only be of sufficient depth as to allow the tube ends
being surrounded by water.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is-
An improved form of tube plate to receive the ends of tubes of steam boilers
by forming suitable bosses or nipples & boring them out, substantially as illustrated
and described.
Dated this 10th day of Tal 1000
JOHN
PHILLIPS,
4, Corona Road, Burnt Ash Hill, Lee, S.E.