IMPROVEMENTS IN GRATE BARS FOR STEAM BOILERS AND OTHER FURNACES
Year: 1884

page_text: We, JOHN STEPHENSON of Toftshaw Lane Dudley Hill near Bradford in the
County of York, Grate Bar Manufacturer, and WILSON TOPHAM of Vulcan Works,
Dudley Hill, Ironfounder, do hereby declare the nature of our Invention for
IMPROVEMENTS IN GRATE BARS FOR STEAM BOILERS AND OTHER FURNACES, to
be as follows:-
-
The object of this invention is, to effect certain improvements upon Letters
Patent granted to James Raper and John Stephenson on the 7th day of February
1871 and numbered 319.
In the Letters Patent above quoted the middle and side bars are made of equal
thickness of metal at the top or face of the grate bar diminishing in thickness
downwards and the top of the cross ribs are made thinner than the middle and
side bars and diminish in thickness downwards. These unequal thicknesses of
metal when cast together we find a great source of weakness in the bar through
unequal expansion and contraction causing the cross ribs to break off from the
middle bars.
In our present improvement we make the middle and side bars and the cross
ribs all one equal thickness of metal on the top or face of the grate bar, thus
preventing the unequal expansion and contraction and its results. This also
secures to us a much larger area or air space on the top of the grate surface.
We also claim in our present improvement the middle and side bars and cross
ribs being all one thickness thus reducing the liability to burn away. To
compensate for the loss of strength consequent upon the reduction of the thickness
of the middle and side bars at the top we give a greater thickness of metal at the
bottom reducing in thickness towards the top of the bars.
D
1007
JOHN WAUGH,
Agent for the said John Stephenson
and Wilson Topham.

page_text: We JOHN STEPHENSON of Toftshaw Lane Dudley Hill near Bradford in the
County of York, Grate Bar Manufacturer, and WILSON TOPHAM of Vulcan Works
Dudley Hill, Ironfounder do hereby declare the nature of our invention for
IMPROVEMENTS IN GRATE-BARS FOR STEAM BOILERS AND OTHER FURNACES, and
in what manner the same is to be performed to be particularly described and
ascertained in and by the following statement :-
The object of this invention is to effect certain improvements upon Letters
Patent granted to James Raper and John Stephenson on the 7th day of February
1871 and numbered 319.
In the Letters Patent above quoted the middle and side bars are made of equal
thickness of metal at the top or face of the grate bar, diminishing in thickness
downwards, and the top of the cross ribs are made thinner than the middle and
side bars, and diminish in thickness downwards also.
These unequal thicknesses of metal when cast together we find a great source of
weakness in the bar, through unequal expansion and contraction, causing the cross
ribs to break off from the middle and side bars.
In our present improvement, we make the middle and side bars and the cross-ribs
all one equal thickness of metal on the top or face of the grate-bar, thus preventing
the unequal expansion and contraction and its results. This also secures to us a
much larger area or air space on the top of the grate surface, and reduces the
liability of the bars burning away. To compensate for the loss of strength
consequent upon the reduction of the thickness of the middle and side bars at the
top, we give a greater thickness of metal at the bottom, reducing in thickness
towards the top of the bars, and in order that our invention may be better
understood we have appended one sheet of drawings in which Fig 1 represents the
plan view or fire side of our improved grate-bar. Fig 2 is a view of the underside,
and Fig 3 is a cross section through line a. b.
The middle and side bars A and cross ribs B are grooved on the fire side of the
grate, and are made all one equal thickness on the top or face side, by which a
larger air space C is obtained, thereby reducing the liability of the bars burning
away or breaking with unequal expansion or contraction; and in order to
compensate for the loss of strength consequent upon the reduction in thickness of
the middle and side bars and to equalize the contraction in cooling after being
heated in the furnace we give a greater thickness of metal at the bottom at A¹
reducing the thickness towards the top of the bars.
Having now particularly described and ascertained the nature of our said
invention, and in what manner the same is to be performed we declare that what
we claim is:
Grate bars in which the middle, side, and cross bars or ribs are made of equal
thickness of metal at the top or fire side, and the middle and side bars thickened
at the bottom substantially in the manner and for the purpose described.
Dated this 30th day of Santambon 1001.
WAUGH & CHAPMAN,
Agents for the Applicants.