Improvements in Pressure Pumps.
Year: 1890

page_text: Date of Application. 16th May, 1890
Complete Specification Left, 16th Feb., 1891-Accepted, 2nd May, 1891
PROVISIONAL SPECIFICATION.
Improvements in Pressure Pumps.
I, CHRISTOPHER KINGSFORD, of Wheatley Lodge, Erith, in the County
of Kent, Engineer, do hereby declare the nature of this invention to be as
follows:-
My invention relates to improvements in pressure pumps and is particularly
applicable to pumps wherein the pressure or resistance increases as the work
proceeds that is where the power required to raise the ram of for example a
hydraulic press is insignificant at first but increases as the tram rises; for this
purpose I employ several plungers controlled by springs as hereafter described and
preferably arranged concentrically one within another, or in such manner that as
the work progresses and the resistance to be overcome increases or becomes
greater, the effective area of the pump plunger or plungers is or are automatically
diminished.
According to my invention, and a convenient way of carrying the same into effect,
is to provide a plunger which is generally solid, being headed or flanged at its lower
or acting end and held at its other end by a key or otherwise to a reciprocative
guide head operated by a hand lever or power. This plunger, hereafter for the
purposes of this Specification called the central plunger, passes centrally through a
second plunger of superior external diameter also flanged or headed at its lower end
and of less length than the central plunger. At its upper end the second plunger
is provided with a gland and there is also a helical spring which acts between the
reciprocative guide or cross-head and the second plunger holding the lower end of
the latter against the head of the central plunger.
A third and still shorter plunger is also provided sliding over the second plunger
and of superior external diameter; the lower end of the third plunger is held
against the flanged or headed end of the second plunger by a second helical spring
acting between the framework of the pump and against the cover of a gland with
which the third plunger is provided at its upper end.
The two helical springs may be separated by a piece of tube or other suitable
contrivance which limits the stroke of the plungers.
It is optional whether the springs abut against the framework of the pump or
against the reciprocative cross-head herein before described. In multiple plungers
both or either may be adopted but generally the former is best when the pump is
actuated by a crank and the latter by a lever.
The third plunger works through the gland of the force pump cylinder so that on
motion being communicated to the reciprocative guide head, the upward motion of
the latter will carry with it the central, second and third concentric plungers
compressing the spring of the third plunger, and the reverse motion will cause the
combined areas of the three plungers to act simultaneously for forcing the liquid.
As however the resistance in the pump becomes greater than the expansile force
of the spring of the third plunger the latter plunger will be held in its upmost
position and the effective area of the plunger will be the area of the central plunger
plus the area of the second. When the resistance increases still more the helical
spring of the second plunger will become similarly compressed and the effective area
will be still further decreased to that of the central plunger.
I do not however limit myself as to the number of concentric plungers employed,
nor to the form of springs although those described are conveniently applied. In
some cases I may provide separate plungers of different sectional areas that is
plungers not arranged one within another concentrically, and I then actuate such

page_text: plungers from a lever or crank or levers or cranks through the medium of springs
so that as the resistance increases the plungers will be consecutively thrown out
of action.
Thoth def M. 1900
CHRISTOPHER KINGSFORD.
By Brewer & Son,
33, Chancery Lane, London, Patent Agents.
COMPLETE SPECIFICATION.
Improvements in Pressure Pumps.
I, CHRISTOPHER KINGSFORD of Wheatley Lodge, Erith, in the County
of Kent, 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 invention relates to improvements in pressure pumps and is particularly
applicable to pumps wherein the pressure or resistance increases as the work
proceeds that is where the power required to raise the ram of for example a
hydraulic press is insignificant at first but increases as the ram rises; for this
purpose I employ several plungers controlled by springs as hereafter described and
preferably arranged concentrically one within another, or in such manner that as
the work progresses and the resistance to be overcome increases or becomes
greater, the effective area of the pump plunger or plungers is or are automatically
diminished.
My invention will be best understood by describing same with reference to
the accompanying drawings.
Figure 1 is a longitudinal vertical section of a pressure pump constructed
according to one modification of my invention and a convenient way of carrying the
same into effect is to provide a plunger A which is generally solid, being headed or
flanged as shown at B at its lower or acting end and held at its other end, by a key
or otherwise to a reciprocative guide head C operated by a hand lever D, or power.
This plunger A, hereafter for the purposes of this Specification called the central
plunger, passes centrally through a second plunger E of superior external diameter
also flanged or headed at its lower end E, and of less length than the central
plunger A. At its upper end the second plunger E is provided with a gland F, and
there is also a helical spring G which acts between the reciprocative guide or
crosshead C, and the second plunger E, holding the lower end of the latter against
the head of the central plunger A.
A third and still shorter plunger H is or may be also provided sliding over the
second plunger E, and of superior external diameter; the lower end of the third
plunger H is held against the flanged or headed end E¹ of the second plunger E, by
a second helical spring I, acting between the framework J, of the pump and against
the cover of a gland K, with which the third plunger H is provided at its upper end.
The two helical springs may be separated by a piece of tube or by other suitable
contrivance which would limit the stroke of the plunger. It is optional whether
the springs abut against the framework of the pump or against the reciprocative
cross head hereinbefore described. In multiple plungers both or either of the
above arrangements may be adopted, but generally the former is best when the
pump is actuated by a crank and the latter by a lever.
The third plunger H works through the gland L of the force pump, cylinder M,
so that on motion being communicated to the reciprocative guide head C, the
upward motion of the latter will carry with it the central A, the second E and
third H concentric plungers, compressing the spring I of the third plunger (being
abutted against the framework) and the reverse motion will cause the combined
areas of the three plungers A E H, to act simultaneously for forcing the liquid.

page_text: As however the resistance in the pump becomes greater than the expansile force
of the spring I, of the third plunger H, the latter plunger H will be held back or
in its upmost position and the effective area of the plunger will be the area of the
central plunger A, plus the area of the second plunger E.
When the resistance increases still more, the helical spring G of the second
plunger E will become similarly compressed and the effective area will be still
further decreased to that of the central plunger A.
I do not however limit myself as to the number of concentric plungers employed,
nor to the form of springs, although those described are conveniently applied. In
some cases I may provide separate plungers of different sectional areas, that is
plungers not arranged one within another concentrically, and I actuate such
plungers or pistons from a lever or crank, or levers or cranks through the medium
of springs, so that as the resistance increases the plungers will be consecutively
thrown out of action.
The following figures will illustrate some of the various modifications under
which my invention is capable of being applied.
Figure 2 shows a double acting pressure pump constructed according to my
invention pumping on the up and down strokes until the pressure in the large barrel
equals the power of the springs; in this case the centre plunger A is formed with
a tail piece A', which passes through a gland F and pushes down the large plunger
or plungers and leaves it or them when the pressure equals that of the springs,
which it never exceeds in the large barrel or spring box S said spring box may be
screwed on to the barrel of the pump, by adjusting which the power of the springs,
contained therein, may be augmented or diminished. It is obvious that when the
resistance equals the power of the springs I and G, the plungers H and E will
respectively cease to follow the tail piece A', and the plunger A will act as an
ordinary plunger pump.
Figure 3 shows in longitudinal section a pump which becomes double acting as
soon as the large plunger or plungers cease acting. The concentric plunger E
acted upon by the spring G will force a superior quantity of liquid at each stroke,
due to its large area, until the resistance equals the power of the spring, as in the
modifications hereinbefore described, whereupon the plunger A with its enlarged
portion A', will work as an ordinary differential double action pump, the area of A¹
being double that of A.
Figure 4 shows also in longitudinal section a modified arrangement with two
barrels M and M'worked alternately, the plunger E in the large barrel being acted
on by a spring. The combined areas of both the small and large plungers A and E
are effective until the pressure in the large barrel equals the resistance of the
spring when the plunger E remains at the top of the stroke, while the sleeve C
actuated by the lever D slides up and down on the rod E', by which sleeve C, the
spring is compressed without moving the plunger E, except to displace the liquid
drawn by the plunger A in its upward stroke, the pump M¹ acting as a suction
pump to supply the small pump M with the liquid.
Figure 5 shows a modification wherein the central plunger passes through the
larger plunger or plungers, as in the modification shown at Figure 1 pulling it or
them up against the spring or springs until the pressure equals the springs when it
becomes an ordinary single plunger pump, the effective area being that by which
the plunger A exceeds that of the tail piece A¹. By this arrangement the springs
are compressed by the upward stroke, which makes it more
suited for pumps worked
by a crank motion.
In
Figure 6 illustrates a modification of the arrangement shown at Figure 2 in its
action, but as the barrel is not divided it has to sustain the maximum pressure.
this arrangement the piston or plunger E is pushed down by the plunger A com-
pressing the spring, the re-action forcing the liquid out of the upper part of the
pump. When the resistance equals the elastic force of the spring, the piston E
ceases to act.
It will be seen that I have shown Figures 3, 4, 5 and 6 with only one extra

page_text: plunger, controlled by one spring in each case, but it is obvious that one or more
concentric plungers, with their accompanying springs, may be employed according
to the requirements of the work to be done.
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 I do not
claim any particular form or construction in pressure pumps, nor do I limit myself
to the use of steel springs as other elastic or compressible materials might be sub-
stituted, but what I claim as my improvements in pressure pumps is :-
1. The adaptation or application thereto of springs or flexible bodies to work or
give motion to plungers of large area, while the pressure against the pump is
comparatively low, which plungers cease to act when the pressure equals the
power of the said springs, a plunger of less area continuing to operate all sub-
stantially as set forth.
2. The construction, arrangement and method of action of pressure pumps
wherein several plungers are controlled by springs substantially as hereinbefore
described and illustrated with reference to the accompanying drawings together
with any mere modification or modifications thereof.
Dated this 16th day of February 1891
.
Witness:
E. G. BREWER,
33, Chancery Lane, London.
CHRISTOPHER KINGSFORD.