Improvements in or relating to Steam Engine Air Pumps.
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
Improvements in or relating to Steam Engine Air Pumps.
I, WILLIAM HAMILTON MARTIN, of 110, Dockquay, Flushing, in the Kingdom
of Holland, Engineer to the Royal Shipbuilding & Engineering Company, "The
Scheldt," Flushing, do hereby declare the nature of this invention to be as
follows:
This invention has reference to improvements in or relating to steam engine
air pumps of the kind in which the barrel is formed with valveless inlet openings
and has working in it a valveless piston or bucket adapted to serve as a piston
valve, such as those of the type known as "Edwards' patent air-pumps." With
these pumps undue pressure may be caused to arise in the condensers to which
such pumps are connected owing to the air pump piston or bucket occupying
such a position in its barrel as to close the inlet openings and so cut off all com-
munication between the condenser and the atmosphere while the engine is not
at work and steam from another source or sources is being discharged into the
condenser. In some cases, condensers are provided with snifting valves, but with
such valves there is great liability of air leaking into the condenser and of water
of condensation escaping therefrom, and an object of this invention is to obviate
such defects for which purpose I provide a relief valve of suitable size between
the condenser or the suction chamber of the air pump such valve being adapted
to open and establish communication between the same and the hot well upon
the pressure in the condenser becoming excessive. In one arrangement I form
the hot well in one with the pump casing and place its upper portion in com-
munication with an annular chamber around the inlet openings to the barrel by
means of pipe or passage, the upper open end of which is fitted with a water
sealed relief valve. This valve may be forced on to its seat by a spring and have
attached to it a spindle that extends through the cover of the hot well or of the
discharge chamber of the pump, so that said valve can be controlled by hand
from the outside if desired. Another defect of air pumps of the kind to which
this invention relates is that, when from any cause the condenser becomes
charged with water so as to drown the pump, the bucket, on descending, will form
a very perfect vacuum under the head valves, and as no air can find its way into
the barrel and the duration of port opening is usually too short to allow the water
to completely fill the barrel, and destroy the vacuum, as it would in an ordinary
air pump, a violent shock will occur on the upstroke when the surface of the water
strikes the head valves and their seats.
For the purposes of avoiding these shocks which are detrimental to the pump
and connected gear I propose to fit to the barrel of the pump, at some little

page_text: distance above the inlet openings to the barrel, a comparatively large and accur
ately loaded air or automatic snifting valve; the position of the valve is such
that if the pump be working under normal conditions, the valve will not admit
air to the barrel owing to the fact that, under such conditions, from the time the
bucket leaves the head valve seat air will commence to leak past it and, by the
time the bucket uncovers the passage to the snifting valve, will have so far reduced
the vacuum as to prevent the pressure of the atmosphere overcoming the load
upon said valve. The load on the snifting valve may be so adjusted as to prevent
air passing into the barrel through said valve uselessly, but that if no air should
pass the bucket owing to there being water only under it, a high vacuum wi!!
be maintained on the downstroke of the bucket until it passes the snifting valve,
when a certain amount of air will be drawn into the barrel, and will act as a
cushion on the upstroke, thus preventing the violent concussion which would
otherwise take place, on the water coming into contact with the head valves and
their seats.
In another arrangement. I propose to place the lower portion of the air pump
barrel in communication with 'the upper part of the condenser by means of an
open pipe or passage arranged so as to communicate with the pump barrel at the
same point as the snifting valve in the arrangement above described.
In some cases where the condenser is placed sufficiently high to prevent the
communicating pipe getting charged with water I prefer to employ the last
described arrangement.
I, WILLIAM HAMILTON MARTIN, of 110, Dockquay, Flushing, in the Kingdom
of Holland, Engineer to the Royal Shipbuilding' Engineering Company, "The
Scheldt," Flushing, 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: --
66
This invention has reference to improvements in or relating to steam engine
air pumps of the kind in which the barrel is formed with valveless inlet openings
and has working in it a valveless piston or bucket adapted to serve as a piston
valve, such as those of the type known as Edwards' patent air-pumps." With
these pumps undue pressure may be caused to arise in the condensers to which
such pumps are connected owing to the air pump piston or bucket occupying
such a position in its barrel as to close the inlet openings and so cut off all com
munication between the condenser and the atmosphere while the engine is not
at work and steam from another source or sources is being discharged into the
condenser. In some cases, condensers are provided with snifting valves, but with
such valves there is great liability of air leaking into the condenser and of water
of condensation escaping therefrom, and an object of this invention is to obviate
such defects for which purpose I provide a relief valve of suitable size between
the condenser or the suction chamber of the air pump and the hot well, such
4

page_text: valve, being adapted, to open and establish communication between the same and
the hot well upon the pressure in the condenser becoming excessive. The accom-
panying drawing, is a vertical section of a construction of pump according to this
invention. 1 is the pump barrel with inlet openings. 2 and discharge or head
valves 3; 4 is the valveless piston or bucket. The hot well 5 is formed in one
with the pump casing 5" and its upper portion is in communication with the
annular suction chamber 6 around the inlet openings 2 to the barrel by means
of pipe or passage 7, the upper open end of which is fitted with a water sealed
relief valve 8. This valve may be forced on to its seat by a spring 9 and have
attached to it a spindle 10 that extends through the cover 11 of the hot well, or
of the discharge, chamber of the pump, so that the valve 8 can be controlled by
hand from the outside, if desired.
On the descent of the piston or bucket of an air pump of the kind referred to
when from any cause the condenser becomes charged with water so as to drown
the pump, the bucket forms a very perfect vacuum under the head valves, and,
as no air can find its way into the barrel and the duration of port opening is
usually too short to allow the water to completely fill the barrel and destroy the
vacuum, as it would in an ordinary air pump, a violent shock will occur on the
upstroke when the surface of the water strikes the head valves and their seats.
For the purpose of avoiding these shocks, which are detrimental to the pump
and connected gear, the barrel 1 is fitted, at some little distance above its inlet
openings 2 with a comparatively large and accurately loaded air, or automatic
snifting valve 12, the position of which is such that, if the pump be working
under normal conditions, the valve will not admit air to the barrel owing to the
fact that, under such conditions, from the time the bucket leaves the head valve
seat air will commence to leak past it and, by the time the passage to the snifting
valve 12 is uncovered, will have so far reduced the vacuum as to prevent the pres-
sure of the atmosphere overcoming the load upon said valve. The valve 12 is
loaded by means of a spring 12" the presence of which may be so adjusted as to
prevent air passing into the barrel through said valve uselessly; but if no air
should pass the bucket owing to there being water only under it, a high vacuum
will be maintained on the downstroke of the bucket, until it passes the snifting
valve, when a certain amount of air will be drawn into the barrel and will act
as a cushion on the upstroke, thus preventing the violent concussion which would
otherwise take place on the water coming into contact with the head valves and
their seats.
In another arrangement, the lower portion of the air pump barrel is placed in
communication with the upper part of the condenser by means of an open pipe
or passage arranged so as to communicate with the pump barrel at the same point
as the snifting valve 12 in the arrangement above described. In some cases
where the condenser is placed sufficiently high to prevent the communicating
pipe or passage getting charged with water I prefer to employ the last described
arrangement.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
claim is:
1. The combination with a steam engine air pump of the kind referred to, rf
a relief valve adapted to control communication between the suction chamber of
the pump, or the condenser connected therewith, and the hot-well, into which said
pump discharges substantially as described for the purpose specified.
2. An air pump of the kind referred to, the casing of which is provided with
a passage from the suction chamber to the hotwell, said passage being controlled
by a relief valve substantially as described and shown.
3. An air pump of the kind referred to, the barrel of which is fitted above its
inlet openings with a loaded air or automatic snifting valve or an open pipe or

page_text: passage communicating with upper part of condenser, substantially as described
and shown.
4. An air pump of the kind referred to constructed substantially as described
with reference to and shown in the accompanying drawing.
Dated this 17th day of September 1898
For the Applicant,
W. LLOYD WISE,
46, Lincoln's Inn Fields, London, W.C., Chartered Patent Agent.