IMPROVE- MENTS IN AND NEW APPLICATIONS OF COMPOUND PUMPS FOR AIR AND VAPOUR
Year: 1880

page_text: LETTERS PATENT to Carl Pieper, Civil Engineer and Patent Agent, of 74,
Belle-Alliance-Strasse, Berlin, S.W., Prussia, for an Invention of "IMPROVE-
MENTS IN AND NEW APPLICATIONS OF COMPOUND PUMPS FOR AIR AND
VAPOUR." A communication from Franz Windhausen, Engineer, of Berlin.
PROVISIONAL SPECIFICATION left by the said Carl Pieper at the Office
of the Commissioners of Patents on the 3rd May 1880.
CARL PIEPER, Civil Engineer and Patent Agent, of 74, Belle-Alliance-Strasse,
Berlin, S.W., Prussia. "IMPROVEMENTS IN AND NEW APPLICATIONS OF COMPOUND
PUMPS FOR AIR AND VAPOUR." A communication from Franz Windhausen,
Engineer, of Berlin.
This Invention relates to improvements in the compound air-pump described in
the English Patent Specification, No. 1678, A.D. 1878, and to new applications of
the same.
The said compound pump consists mainly of two ordinary air-pumps of different
capacity combined in such a manner that the large pump aspires air and vapour
from the receiver and delivers them in a state of medium recompression to the
small pump, while the latter after compressing them to the tension of the atmo-
sphere discharges them into the surrounding air. A condenser may be inserted
between the two pumps for condensing the vapours when such are to be extracted.
The improvements forming the subject-matter of this Invention are as follows:-
The suction-valves are drawn against their seat by springs, whereas they are
opened by a mechanism composed of levers and rods, and which is worked from
an eccentric or cam fixed by preference on the main shaft of the machine. When
the levers release the valves they close by the action of the said springs.
Between the suction and the discharge pipe of the large pump (or the suction-
valve box and the discharge-valve-box) a return-valve is inserted, which is pressed
on its seat by a spring. This spring is regulated in such a manner that when the
pump begins to work the valve will open and allow a part of the air to flow back
from the discharge-pipe into the suction-pipe until the tension of the air which is
being expelled has decreased to a certain fixed degree.
The new applications of the compound pump consist in its use for evaporating
and concentrating liquids, and especially such liquids whose boiling-point under
atmospheric pressure lies very high. Moreover the pump may with great advantage
be used for dessicating meat, vegetables, and other organic substances for the
purpose of preserving them, and finally it may be employed for the dessication
of dead human and animal bodies with the intent of preserving them from
putrefaction.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Carl Pieper in the Great Scal Patent Office on the 3rd November
1880.
CARL PIEPER, Civil Engineer and Patent Agent, of 74, Bello-Alliance-strasse,
Berlin, S.W., Prussia. "IMPROVEMENTS IN AND NEW APPLICATIONS OF COMPOUND
PUMPS FOR AIR AND VAPOUR." A communication from Franz Windhausen,
Engineer, of Berlin.
This Invention relates to improvements in the compound air pump described
in the English Patent Specification No. 1678, A.D. 1878, and to new applications
of the same.
The said compound pump consists mainly of two ordinary air pumps of different
capacity combined in such a manner that the large pump aspires air and vapour
from the receiver and delivers them in a state of medium recompression to
the small pump, while the latter after having compressed them to the tension of
the atmosphere discharges them into surrounding air.
A condenser may be
inserted between the two pumps for condensing the vapours when such are to be
extracted.
The improvements forming the subject matter of this Invention are represented
on the annexed two Sheets of Drawings.
Figure 1 is an outside view of the improved pump; Figure 2, a plan; Figure 3,
a section on a larger scale according to the line X, X, Y, Y, of Figure 1,
but without the mechanism by which the pistons are worked. Figs. 3ª, 3b, 4,
and 5 show details, while Fig. 6 represents a modified arrangement of the
pump.
Di is the large pump; D², the small pump; and F, the condenser. The pump D',
which is by preference double acting, is in communication by means of the suction
pipe with the receptacle in which the vacuum is to be produced, and by the
discharge pipe c¹ with the condenser F. The pipe c¹ is consequently the suction-
pipe of the small pump D², which discharges by the pipe c² its contents of air and
the water aspired from the condenser. n¹, n¹, are the suction valves, and n³, n²,
the discharge valves of the large pump. Of the latter valves the upper one is
pressed against its seat by its weight, the lower one by a spring, and both valves
open automatically as soon as the pressure in the cylinder exceeds the pressure in
the discharge pipe.
While the parts so far described do not present any features of material
novelty as compared with the machine of the Patent No. 1678, A.D. 1878, the
improvements which the pump has undergone will now be explained.
The suction valves, which in the former machine were alternately opened and
closed at the very beginning of each stroke by a rod passing with a certain amount
of friction through the piston, are now operated from the outside by a mechanism
consisting of an eccentric or a cam disk o² keyed by preference on the main shaft q,
or otherwise rotated at the required speed, and acting by means of a rod and the
levers o¹, o¹, or of other equivalent devices on the stem of the said valves., The
levers o', o¹, which are preferably made to a certain degrec elastic, serve however
only to open the suction valves, whereas either valve is closed by being drawn
against its seat by a spring as soon as it is relieved of the pressure of the
corresponding lever.
The eccentric or cam disk and the parts connected therewith are arranged to
actuate either suction valve in such a manner that the valve will not be opened
until the air remaining in the cylinder at the end of any stroke has re-expanded to
a certain degree (and by preference to about the pressure in the suction pipe), and
that in consequence the corresponding discharge valve has been securely closed
again.
The opening of the suction valves is thereby at the same time facilitated.

page_text: The closing of either of these valves takes place when the piston is at or near the
end of its stroke. Considering that the air which the piston p expels at the
commencement of its working has a tension considerably above the mean pressure
of the air discharged from the large cylinder, the piston would at first have to
overcome too great a resistance if an arrangement were not provided for by which this
pressure is prevented from exceeding a certain limit. This arrangement consists in a
return-valve inserted between the suction pipe and the discharge pipe of the large
pump, or between the boxes of the suction valve and the discharge valve, the said
return valve allowing a part of the air discharged to return into the suction pipe
until the tension of the air which is being expelled has decreased to a certain fixed
The
degree. This valve may be constructed as is shewn in Figs. 1, 2, and 4.
box w which encloses the valve is divided by a horizontal partition 8¹ into two
chambers 8 and 83, the former communicating by the channel 2 (see also Fig. 5)
with the box of the suction valve n', the latter by the channel with discharge
valve box n. 84 is a spring of any suitable form by which the valve is pressed
against its seat on the partition wall 8¹. Supposing this spring to be regulated in
such a manner that the valve will open at a difference of pressures on its two sides
of, for instance, one tenth of an atmosphere, air will or may at every stroke be
returned from the discharge valve box to the suction valve box until the maximum
surplus of pressure in the pump above the pressure in the suction pipe is reduced
to the said tenth part of an atmosphere. When this point is attained the vaive
does not open any more, and for providing against any subsequent passage of air it
Instead
may then be pressed tightly against its seat by means of the screw 85.
of using the spring 8 the valve may be loaded to a corresponding degree by a
weight.
The packing of the piston of the large pump is substantially the same as the
packing of the formerly patented machine; p' is a metallic packing-ring, and 25 a
ring of india-rubber or other air-tight and sufficiently flexible material, which is
secured by means of its flanges and of the ring p between the body and the cover
of the piston, so that the air which is allowed to enter into the hollow body of the
piston by means of a pressure reduction-valve R and a pipe 1 (see Figs. 3
and 3b), and which can pass through holes in p and p into the space between the
rings and 22 will press the said ring p against the packing ring p*, and
the latter against the wall of the pump.
The main parts of the pump represented by Fig. 6 are similar to those of the
one shown by Fig. 5, Sheet 2, of the Patent No. 1678, A.D. 1878, but the
suction-valves of the former are actuated in the hereinbefore described improved
manner by means of an eccentric o². It may be mentioned that this machine.
is represented by the Drawing is not provided with a condenser, but that water
may be injected by the pipes t¹ into the small pump which is double-acting.
GOO
By means of the compound pump fitted with the aforesaid improvements a
rarefaction of air and vapour as low as 1/coo of an atmosphere, and even less, may be
attained, which is a degree far beyond the rarefaction that can be arrived at by
common air-pumps used for industrial purposes.
The compound air and vapour pump invented by my correspondent, whether
constructed according to the Drawings of the former Patent, or whether provided
with the herein before described improvements, may with advantage be used not
only for the process of concentration of sulphuric acid described in my Patent
referred to above, but also for the evaporation and concentration of liquids. in
general, moreover for the dessication of meat, vegetables, and other organic
substances, as also of dead human and animal bodies when such are to be preserved
from putrefaction, and for all other industrial processes requiring to be executed in
a vacuum.
Having thus described the nature and object of this Invention, and the manner
in which it is to be carried out in practice, as communicated to me by my corre-
spondent, I hereby claim as new and important features of the same,―
1. In combination with the suction-valves of an air-pump D¹ the eccentric or

page_text: cam-disk o² or its equivalent, and a suitable intermediate mechanism for operating
the said valves, substantially as described.
2. In a compound air-pump, the combination with the pump D' of the return-
valves provided with the spring or its equivalent, such as a weight, substantially
as stated and for the purpose specified.
3. The application of a compound air and vapour-pump for the purpose of
evaporating and concentrating liquids for the dessication of organic substances,
and for other industrial purposes requiring to be carried out in a vacuum, as
herein before described.
In witness whereof, I, the said Carl Pieper, have hereunto set my hand and
seal, this Eighteenth day of October, in the year of our Lord One thousand
eight hundred and eighty.
CARL PIEPER. (L.S.)