Improvements in Vacuum Pumps.
Year: 1893

page_text: Date of Application, 24th June, 1893
Complete Specification Left, 8th Mar., 1894-Accepted, 14th Apr., 1894
PROVISIONAL SPECIFICATION.
Improvements in Vacuum Pumps.
WILLIAM PRICE ABELL Tooley Park, Hinckley, England, and also of
L'Union House in the County of Essequebo, British Guiana Whitworth Scholar,
Engineer, do hereby declare the nature of this invention to be as follows:-
The object of this invention is firstly to connect the two ends of a vacm. pump
at the completion of each stroke in such a way that when the vacm. in the end
just beginning to opperate exceeds that in the end in which the stroke has just been
completed the ports making the connection are closed automatically, & thus prevent
waste & facilitate the efficiency of the pump. Secondly the application of a
compensating or bye pass gear to existing vacuum pumps & thereby rendering
them more efficient.
To accomplish the aforementioned object, I connect the two ends of an ordinary
vacuum pump by means of a port. This port is closed by one or more valves,
(preferably two) each valve is alternately opened mechanically at the end of the
pump's stroke by a projecting lever, or some suitable moving part, preferably the
plunger, the other valve being opened outwards by the greater vacuum at
the completed end. Consequently, when the vacuum in the end just beginning to
operate exceeds that in the end just completed, this valve closes & thus severs the
connection between each end. On the return stroke the operation is reversed, &
the valve that closed automatically by the difference of vacuum, is now opened
mechanically by the lever, & the valve that was last opened mechanically, is now
closed automatically by the difference of pressure on the completion of the other
end of the stroke.
I preferably use differential tappet or seat valves, but can use the ordinary
slide valve. By this invention, each end of the pump is provided with bye pass
valves, which operate at each end of the stroke, by which the detrimental effects of
clearance & absorbed air are almost entirely overcome.
Such an arrangement has a twofold advantage. The delivery air entrapped in
the water & clearance space at the end of the stroke is transferred from where it is
detrimental (by preventing the suction valves from opening at the commencement
of the return stroke) to where the pressure is required, i.e., on the delivery side of
the plunger, thus ensuring a larger volume of air being sucked in & consequently
a more perfect vacuum created than would otherwise be the case.
Dated this 23rd day of June 1893.
WILLIAM PRICE ABELL.
5
COMPLETE SPECIFICATION.
Improvements in Vacuum Pumps.
WILLIAM PRICE ABELL Whitworth Scholar, Assoc. M. Inst., C.E., of
Tooley Park, Hinckley, England, and L'Union House Essequebo, British Guiana,
do hereby declare the nature of this invention and in what manner the same
O is to be performed, to be particularly described and ascertained in and by the
following statement :-
The object of this invention is firstly to connect the two ends of a vacuum pump
at the completion of every stroke; I preferably do this in such a way that when
the vacuum in the end just beginning to operate exceeds that in the end in which

page_text: the stroke has just been completed, the ports making the connection are closed
automatically & thus prevent waste & facilitate the efficiency of the pump.
Secondly, the application of compensating, or bye pass gear to existing vacuum
pumps to thereby render them more efficient.
To accomplish the afore mentioned objects, I connect the two ends of an ordinary
vacuum pump by means of a port, this port is closed by one or more valves; each
valve is alternately opened mechanically at the end of the pumps stroke by a
projecting lever on some suitable moving part, preferably the plunger; the other
valve being opened outwards by the greater vacuum at the completed end,
consequently when the vacuum in the end just beginning to operate, exceeds that
in the end just completed this valve closes, & thus severs the connection between
each end; on the return stroke the operation is reversed, & the valve that
closed automatically by the difference of vacuum is now opened mechanically
by the lever; & the valve that was last opened mechanically, is now closed
automatically by the difference of pressure on the completion of the other end of
the stroke.
Ordinary slide valves can be used instead of the tappet & seat valves.
By this invention each end of the pump is provided with "bye pass" valves
which operate at each end of the stroke, & by which the detrimental effects of
clearance and absorbed air are almost entirely overcome. Such an arrangement
has a twofold advantage.
The delivery air entrapped in the water & clearance space at the end of the
stroke is transferred from where it is detrimental (by preventing the suction valves
from opening at the commencement of the return stroke), to where the pressure
is required; i.e., on the delivery side of the plunger; thus ensuring a larger volume
of air being sucked in and consequently a more perfect vacuum created than
would otherwise be the case.
Similar letters of reference indicate corresponding parts in the several figures.
Figure 1 is a sectional elevation through V. W. of a plunger pump fitted
according to my invention.
Figure 2 is a part sectional plan of Fig. 1 through .. y.
Figure 3 is a plan partly in section of equilibrium valves used according to my
invention.
Figure 4 is a sectional elevation of a piston pump illustrating a modification of
my invention.
Figure 5 is a sectional elevation of a pump illustrating another modification.
Figure 6 is an enlarged part sectional elevation of Figure 5 but showing another
modification of my invention.
Figures 1 & 2 show my invention applied to an ordinary vacuum pump by
replacing the usual band doors with a cover G connected with the compensating
valves as here described. A is the plunger; b, b', the vacuum pump case; c care
valves; e e¹ are ports leading to highest part of the pump casing; d d' are
spring levers fastened to & moving with the plunger A.
The action of the invention is as follows:-Supposing the plunger to have been
just drawn into the chamber b', there will be a vacuum in chamber b, & delivery
pressure in just as the stroke is being completed the spring lever d presses
suddenly open the valve C, thus opening communication between the two ends b & b¹,
through the ports e e¹²; and by this means creating a vacuum on the side b',
before the stroke from that end begins; now the valve c', being loose & free to
close does so automatically as soon as the new stroke makes the vacuum in the
chamber greater than in b.
In Figure 3, valves of the equilibrium type are shown.
In Figure 4, the ports e¹ e lead from the highest part of the
these are alternately connected to the suction port e by the port in the slide
pump casing;
valve C, in this valve c is another port e, this port connects the two ends of the
pump when the piston a completes each stroke; this slide valve is moved by suitable
mechanism such as an eccentric fixed approximately at right angles to the pump

page_text: crank whereby the valve has its quickest motion when the piston is at the end of
its stroke; in the type of pump known as the Worthington, the piston of one pump
can be made to work the valve of the other.
This arrangement works as follows:-
Suppose the piston a to have just exhausted chamber b, the valve is in position
shown in Fig. 4 and by means of port both sides of the pump chamber & b
are connected, the slide valve c is carried the opposite direction to the piston &
thereby connects the new exhausting side b¹ through the portsel & with the
exhaust until the stroke is completed and vice-versa.
In Figure 5, is shown my invention applied to an ordinary piston vacuum pump
or condenser; a is the piston e & el are ports leading from each end of the cylinder
to the highest part of the pump casing or preferably into recesses in the valve
plate g³, these can be simply pipes bolted or screwed into existing pump cylinders;
these are placed so that the piston a passes them as it nears the end of each stroke ;
93 are the ordinary suction & delivery valves.
The action of this arrangement of my invention is as follows:-
Suppose the piston a to have just reached the end & in so doing passed the
port el, this allows the vacuum on the side b to draw over water & air from the
side 6, until they are both in equilibrium, thus enabling the piston to start on
the return stroke with a partial vacuum on the side b', the piston a on the return
stroke passes the port e¹ and thus shuts off the connection between the two ends of
the pump case b, b¹.
To avoid the loss that would arise from very wide ports I find it desirable
sometimes to fix a valve opening inward on the top of each of these ports e', e, this
is shown in an enlarged section by Fig. 6; by this arrangement so soon as the
vacuum in the end 61 exceeds that in the end b, the valve closes, thus severing
the connection between the two ends b¹ & before the piston a passes the port e¹.
I am aware that slots have heretofore been cut in pump cylinder ends for the bye
pass of air; but these have hitherto been on a level with the top of the piston
or cylinder, and much below the highest water level (consequently they are flooded
& practically useless) one special feature of my invention herein described is
projecting the ports to the highest part of the pump chamber in such a way that
the water is drawn below that level and an air connection made at each end of
the stroke in the least possible time; thus taking advantage of the law that air
travels many times faster than water.
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 :-
1st. The compensating valves c, c', Fig. 1, 2 & 3 in vacuum pumps such that
each is opened mechanically, alternately at the end of the pump stroke, & each
closes alternately automatically when the air-pressure on the suction side is less
than that on the delivery side; substantially as & for the purpose described.
2nd. The levers d, d¹ in Fig. 1, 2, 3 or other similar mechanism whereby the
compensating valves c, c¹ are opened by the plunger A or its rod substantially as
& for the purpose described.
3rd. The combination of bye pass or compensating valves c, c' Figs. 1, 2, 3 with
existing vacuum pumps substantially as & for the purpose described.
4th. In connection with vacuum pumps & condensers, the use of ports e, el Fig. 6
and valves c, c¹ situated at the highest part of the pump chamber 6, as described
for making & breaking connection between the pump chambers at each end of the
stroke.
5th. In connection with vacuum pumps the use of ports e, e¹ Fig. 6 & seatings
for one or more valves e, the said valves being arranged to open inwards so
that they automatically close the connection between the two ends of the pump
chambers b, b so soon as the vacuum on the new stroke is greater than the vacuum
on the last completed stroke substantially as & for the purpose described.

page_text: 6th. In connection with the class of vacuum pumps known as plunger pumps.
the use of ports e, e¹ Figs. 1, 2, 3 arranged above the plunger A in the highest
part of the pump chamber b, bas & for the purpose described.
7th. Ports or pipes e, e¹ Fig. 5 extending from the highest part of the pump
chamber to the pump barrel, to form connection with both ends b, at the
completion of each stroke as &c.
8th. In connection with vacuum pumps or condensers a slide valve c Fig. 4
containing two ports e & e²; one for regulating the suction & discharge of the
pump, & the other port for making the connection between both ends b, 6' of the
pump chamber at the completion of each stroke, substantially as & for the purpose
described.
9th. The general arrangement of compensating or bye pass valves and vacuum
pump substantially as & for the purpose described.
Witnesses-
WILLIAM HENRY ELLIS.
HUGH SMITH.
Inventor.