IMPROVEMENTS IN SAFETY VALVE APPARATUS
Year: 1885

page_text: We VINCENT NEWTON COWBURN of 489 Grey Mare Lane Openshaw near
Manchester in the County of Lancaster Engineer and ALFRED JOHNSON of
Weaverham Grange Hartford in the County of Chester Gentleman do hereby
declare the nature of our invention for IMPROVEMENTS IN SAFETY VALVE
APPARATUS to be as follows:-
This invention has for its object the improvement of that description of safety
valve apparatus commonly known as Cowburn's safety valve and more particularly
to that kind which formed in part the subject of the Letters Patent granted to
Thomas Cowburn dated the 10th day of June 1871 N° 1546 and which class of
apparatus is characterised by the use of a series of small valve passages to increase
the circumferences and lessen the areas so as to use less weight; extending the
inlets for the escape of steam and to gain various advantages.
According to our present invention we arrange a number of valves of the
character described in the specification of the said Thomas Cowburn before
mentioned equidistant around a circle and properly weighted by a series of
superposed adjustable weights and this group or series of valves are caused to
rise by the partial revolution of a piece or ring carrying inclined planes, or
inclined surfaces, and this partial revolution is imparted to the piece with inclined
planes by means of a central stem or rod which also carries at its upper end the
central valve which relieves pressure arising from low water and indicates that
condition, and the other end of this stem carries a projection or part adapted to
counterbalance a pivotted lever connected to the float resting upon the liquid which
float is to be the prime mover of the apparatus in order to let off steam to prevent
overpressure or to set in operation the central valve to let off steam of too high
pressure arising from low water and thus indicate that condition in the generator.
The motion in a rotatory direction to the ring or piece carrying the inclines, which
move the grouped separate steam valves imparted by the rise of the central valve
stem, is derived from curved courses into which a stud or projection from said stem
engages and follows as it is raised by the float lever and provision is also made for
this lever and its connections being made adjustable and applicable in one, or
another direction, to meet the circumstances of the case.
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page_text: By these means we are enabled to adapt our invention not only to the purposes
of indicating and relieving too high pressures in steam generators but also to
indicate the dangerous or too low level of water in such vessels with equal facility
as well as to adapt this class of apparatus to forms of steam generators to which
previously such application had been difficult or inconvenient in practice, in order
to prevent explosion.
Another advantage which we ensure by our invention is the security it affords
against tampering with the valves to prevent escape of steam when the proper
maximum has been reached in the generator. .

page_text: We VINCENT NEWTON COWBURN of 489 Grey Mare Lane, Openshaw near
Manchester in the County of Lancaster, Engineer, and ALFRED JOHNSON of
Weaverham Grange Hartford in the County of Chester Gentleman, do hereby
declare the nature of our invention for IMPROVEMENTS IN SAFETY VALVE APPARATUS,
and in what manner the same is to be performed, to be particularly described.
and ascertained in and by the following statement :-
'
This invention has for its object the improvement of that description of safety
valve apparatus cominonly known as Cowburn's safety valve and more particularly:
to that kind which formed in part the subject of the Letters Patent granted to
Thomas Cowburn dated the 10th day of June 1871 No 1546 and which class of
apparatus is characterized by the use of a series of small valve passages to increase
the circumferences and lessen the areas so as to use less weights; extending the
inlets for the escape of steam and to gain various advantages.
According to our present invention we arrange a number of valves A of the
character described in the specification of the said Thomas Cowburn before
mentioned equidistant around a circle and properly weighted by a series of
superposed adjustable weights as described in the said former specification, or by
means of hollow weighted containing vessels B slung at B¹ on the valves A as
shewn closing the passages A2 and this group, or series, of valves A are caused
to rise by the partial revolution of a piece, or ring, C, loosely fitted (at c¹) so as
to enable D to slide therein, so as to be capable of rotation on the circular part k
of the framing K carrying inclined planes c, or inclined surfaces, and this partial
revolution is imparted to the piece C, with inclined planes c, by means of a central
stem or rod D of square cross section from 1 to 2 sliding loosely in an upper square
central cross-head C¹, having spaces left between its arms and tube Cs for steam to
pass freely away, which rod D also carries at its upper end the central valve E
which valve by opening the passage A' relieves any pressure that may arise from
low water and indicates the existence of that condition of things in the
generator H. I, I shews the water line. The other end of this stem D carries a
weight which constitutes the load put upon the central valve E, this stem D
also carries a projection d, or double pin part. A weight e³ is adapted to counter-
balance, through the instrumentality of short arms e¹, e¹ pressed down thereby, the
pivotted levers F connected by stems F1 to the floats G resting upon the liquid.
C³ is a lower bearing or guide to rod D. These floats as is obvious are the prime
movers of this apparatus when the object is to let off steam so as to prevent
excessive pressure or to set in operation the central valve E to let off steam on low
water occurring and thus indicate that condition in the generator. The desired
motion in a rotatory direction to the ring or piece C carrying the inclines c which
move the grouped separate steam valves A imparted by the rise of the central
valve stem E, is derived from curved courses h, h' arranged at opposite sides of
rod D and engaging each one of the opposite ends of the pin d (shown the farther
side one in full lines and the other the nearer side one in dotted lines) into which
curved courses this stud or projection d from said stem D engages and follows as it

page_text: is raised by the float levers F and provision is also made for this lever and its
connections being made adjustable and applicable in one, or another direction, to
meet the circumstances of the case.
An arrow or finger or other indicator applied to the dish rim k¹ and indications
on the rotating part C will serve to indicate deviations from the normal working
level of the water line in the boiler or generator. The dish will serve to catch
and retain water that may flow over from the valves.
By these means we adapt our invention not only to the purposes of indicating
and relieving too high pressures in steam generators by the rising of valve E and
parts D and e², independently but also to indicate the dangerous or too low level of
water in such vessels with equal facility and so that both operations may be
performed simultaneously or independently as circumstances may require insuring
means of escape for the steam and without necessity for the use of ponderous
appliances which previously were employed occupying great space, as well as to
adapt this class of apparatus to forms of steam generators to which previously
such application had been difficult or inconvenient in practice, in order to prevent
explosion.
Another advantage which we ensure by our invention is the security it affords
against tampering with the valves to prevent escape of steam when the proper
maximum has been reached in the generator.
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 :-
The manufacture and use of the improved construction of safety valve adapted to
indicate and relieve too high pressures in steam generators and to indicate lowness
of water therein either simultaneously or independently, substantially as described
and shewn in the drawings.
Dated this 4th day of June 1886.
WM BROOKES & SON,
Agents for the said Vincent Newton Cowburn 30
and Alfred Johnson.