Improvements in or relating to the Coverings of Hand Holes in Steam Chests, Headers, Boilers, Economisers, or other Vessels.
Year: 1891

page_text: Date of Application, 9th July, 1891
Complete Specification Left, th Apr., 1892-Accepted, 14th May, 1892
PROVISIONAL SPECIFICATION.
Improvements in or relating to the Coverings of Hand Holes in
Steam Chests, Headers, Boilers, Economisers, or other Vessels.
I, JOHNSON MILLS of Swinton Park near Manchester in the County of
Lancaster Engineer do hereby declare the nature of this invention to be as
follows:-
This invention relates to the coverings for hand holes for use in steam chests,
headers, boilers, economisers, or other vessels in which pressure is contained, and
the object of this invention is to construct a cap or cover that will form a perfectly
tight joint, and in the event of any defect in the several parts in connection with
cover will prevent the sudden outflow or explosion of steam or other contents
through said hole.
In this invention I form the hand hole in the boiler or other vessel, preferably of
an elongated or oblong form. I place round near the edge, and on the inner side of
Baid hole, or on the claw edge of clamp hereinafter described, a ring of asbestos or
other suitable packing material. I form a clamp of a concave form with a claw
edge of an elongated or oblong shape corresponding to the shape of hand hole but
Bomewhat larger than said hole, so as to form an internal cover terminating with a
shank or spindle.
I insert the aforesaid concave end into the boiler or other vessel, by passing
the narrow part of concave end through the wider part of band hole, and then
turning the concave end round so that the claw edge rests on the ring of
asbestos or other packing herein before described, with the shank passing through
the hole to the outside and terminating in a screwed end.
I form the centre portion of shank by turning said shank so as to fit thereon a
cap or cover to the outside of hand hole with the edges of said cover resting on the
outer edge of hand hole.
The screwed end of shank is of smaller diameter than the hole in aforesaid
clamp so as to pass easily through said hole, and may when preferred be formed
with a rivet passing through the centre and rivetted to the concave portion of
clamp and also to the extreme end of screwed spindle, in order to afford greater
security in case of fracture.
1 secure the herein before described concave end of clamp that is placed over
hand hole on the inside of vessel, and also the cap that is placed over the outside
of hand hole, by means of a nut fitted on screwed end of shank or spindle, which
when tightened effectually prevents any escape of steam or other contents, by
compressing the aforesaid ring of asbestos or other packing material between the
claw edge of clamp and the inside of plate of boiler or other vessel.
By these means the effect of increased pressure in the boiler or other vessel is to
cause a tighter joint irrespective of any defect in the bolte, screws, or other parts
in connection with cover, or the destruction of the outside cover, as the concave
form of the internal cap or cover would prevent the sudden explosion of steam or
outflow of contents.
Thind an Oh Jow of Ta1– 1900.

page_text: COMPLETE SPECIFICATION.
Improvements in or relating to the Coverings of Hand Holes in
Steam Chests, Headers, Bollers, Economisers, or other Vessels.
1, JOHNSON MILLS of Bank Top, Swinton Park near Manchester in the County
of Lancaster 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 :—
This invention relates to the coverings for hand holes for use in steam chests,
headers, boilers economisers or other vessels in which pressure is contained, and
the object of this invention is to construct a concave or hollow metallic cap or
cover with a shank or shanks formed thereon in one piece by which a perfectly
tight joint may be obtained without the aid of an outside cap or cover, and in the
event of any defect in the several parts in connection with cover, will prevent the
sudden outflow or explosion of steam or other contents through said hole. I attain
this object by the means hereinafter described and as illustrated in the accom-
panying two sheets of drawings.
In the several views therein shown similar letters refer to similar parts.
Fig. 1 represents the side view of an oval or oblong cap or cover constructed
according to this invention.
Fig. 2 is a transverse section of the same in connection with a boiler or other
plate, and
Fig. 3 is a plan view of said cap or cover.
In this invention I form the hand hole a in the boiler. or other vessel > of an
elongated or oblong form. I construct a cap or cover c of a concave or hollow
form with a claw edge c¹ of an elongated or oblong shape as represented in Fig. 3,
corresponding to the shape of hand hole in a boiler or other vessel but somewhat
larger than said hole, so as to act as an internal cover with a shank or spindle c³
forming part of cover, projecting through the hand hole to the outside.
I form the aforesaid cover or clamp c, and. the shank or spindle e' dependent
therefrom in one piece, either of cast steel, wrought steel, wrought iron or other
suitable material.
I place round near the edge, and on the inner side of said hole, or on or
under the claw edge of clamp herein before described, a ring of asbestos or other
suitable packing material d. I insert the hollow end of the clamp c into the boiler
or other vessel by passing the narrow part of said hollow end through the wider
part of hand hole a and then turning the end round so that the claw edge c¹ rests
on the ring of asbestos or other packing d'herein before described with the shank
and the screwed end c³ passing through the hole to the outside. I fit thereon a
clamp or cross bar e which I place over or across the outside of hand hole d with
the edges of said clamp resting on or near the edge of hand hole.
The screwed end of shank is of smaller diameter than the hole et in aforesaid
clamp or cross bar e so as to pass easily through said hole.
Isecure the hereinbefore described concave end of cover c that is placed over
hand hole a on the inside of vessel and also the clamp or cross. bar e that is placed
over the outside of hand hole, by means of a nut fitted on screwed end c³ of
shank or spindle which when tightened effectually prevents any escape of steam
or other contents by compressing the aforesaid ring of asbestos or other packing
material & between the claw edge c¹ of clamp c and the inside of plate b of boiler
or other vessel.
In a modification of my invention when the herein before described cover is
required of larger dimensions, I construct said cover with two shanks or spindles c³,
as represented in Figs. 4 and 5 on drawing.
By the use of an oblong cap or cover such as herein before described the hand
holes in boiler or other vessel are not required to be bored as it is not necessary for

page_text: the cap or cover to be an exact fit, any slight irregularity in shape being neutralized
by the washer d which is placed on the inside of the vessel; the flanged edge c¹ is
able to be retained entire in consequence of the oval or oblong form of cover c
which enables said cover to be passed through the hole in the manner herein before
described; the outside clamp or cross bar is only required to fix the cover and not
to form a joint.
By these means the effect of increased pressure in the boiler or other vessel is to
cause a tighter joint irrespective of any defect in the bolta, screws, or other parts
in connection with cover, or the destruction of the outside cross bar e.
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 :-
Covering the hand holes in steam chests, headers, boilers, economisers or other
vessels by the use of a concave or hollow cap or cover of an oblong or oval form
such as c, Fig. 3, with a shank or shauks such as formed thereon in one piece in
the manner and for the purpose substantially as herein before described.
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THOMAS PRESCOTT,,
53, Arcade Chambers, St. Mary's Gate, Manchester,
Agent for Applicant.