A SYSTEM OR COMBINATION OF PUMPS FOR PRODUCING VACUUM
Year: 1885

page_text: دو
I PETER JENSEN Fel Inst P.A of 33 Chancery Lane in the County of Middlesex
do hereby declare the nature of said invention for "A SYSTEM OR COMBINATION
OF PUMPS FOR PRODUCING VACUUM (a communication to me from abroad by
Ludwig August Riedinger of 25 Eisenhammer strasse Augsburg Germany Manu-
facturing Engineer) to be as follows:-
In simple piston pumps a vacuum of only about 10mm of mercury is attained
in closed spaces; which is even then the case when water is injected into the pump
cylinder in order to fill the detrimental spaces and in order to attain a better
tightness or packing of the piston because it lies in the nature of the thing that
then the limit of the rarefaction aimed at depends upon the pressure of the steam
to the temperature of the water injected. A greater vacuum may be attained if a
second namely a dry pump is inserted between the space to be exhausted and the
injector (first pump) which second pump whilst its suction pipe is connected to the
space to be exhausted has its delivery force pipe connected to the injector pump,
between the first and the second pumps a difference of pressure is thus produced
which is indicated by a further increase of the vacuum in the closed space. Up
till the present time two piston pumps have been used in combination with each
other for the described purpose and in the manner intimated.
A rotary pump or centrifugal exhauster may however be used as secondary or
inserted pump in combination with a primary pump namely a dry piston pump or
one running with injection in the sense of the above statement and this application
forms the subject of the present invention..
By the combination of a piston pump with a rotary pump or a centrifugal
exhauster in such a manner, that the pressure space of the latter forms the suction
space of the former, a greater vacuum is attained than by the combination of two
piston pumps, and as against this known arrangement the new combination is
advantageous in such cases, in which chemical or physical processes are to be

page_text: •
effected in a vacuum by which processes large volumes of gas or vapour are
generated, which must be carried off out of the chamber for the maintenance of
the vacuum.
But piston pumps are not sufficient for exhausting several thousand cubic meters
of gas per hour; on the other hand such volumes of gas or vapour may easily be
drawn out by means of a rotary pump or centrifugal exhauster, if the pressures
are not great-a condition which is fulfilled by using rotary pumps or centrifugal
exhausters as secondary in the manner above described, because only a small
difference in the pressure obtains between the vacuum space and the suction space
of the primary pump.
This difference of-pressure namely depends upon the circumstance in what
relation the sizes of the combined pumps are to each other. If the alteration of
pressure of the conducted gases follows according to the Law of Mariotte, then the
capacity of the primary pump must be to that of the secondary pump as the
pressure in the exhaused space (suction space of the secondary pump) is to the
pressure in the suction space of the primary pump (pressure space of the secondary
pump). If it is not possible by means of one rotary pump or one centrifugal
exhauster to condense the gas exhausted from the vacuum space so far that a piston
pump of the size adapted for the conduction of the same to the outer air suffices it
is only necessary to insert two or more behind each other and between the piston
pump and the vacuum space in such a manner that the pressure or delivery space
of one pump forms the suction space of the next, so that an increase of pressure
and decrease of volume of the separated gas or vapours take place from pump to
pump. It is therefore possible under all conditions so to arrange the differences of
pressure of a single pump according to the requirements; and lastly a rotary pump
or centrifugal exhauster may be used as the primary pump instead of a piston
pump.
With such gases which condense on contact with liquids, such for instance as
steam on the injection of water into the steam space, such a condensation is
inserted between the primary and secondary pump. The latter then only requires
to deliver the condensation fluid augmented by the product of condensation and
"the air which may be carried into the condenser, and therefore only be able to
attain a very much smaller bulk, than if it had conducted the gas led to it from
the second pump itself.
"
Instead of using a piston pump here as condenser pump (primary pump) a
pump of any suitable construction may be used (such as a jet, pump, rotary
pump etc.).
If for instance water or a salt solution should come into the rarefied space, part
☐ of the water forms steam and hereby takes up heat whereby the remaining
portion is more or less cooled under certain circumstances forming ice.
But as the steam produced has a great specific volume by an extremely small
pressure and it is therefore necessary by a considerable production of cold for such
vacuum cooling or refrigerating apparatus to convey away such large volumes of
vapour out of the cooling chambers or refrigerators under vacuum, piston pumps
because of their immense dimensions are not practically of use. Other means.
have therefore been resorted to for the removal of water vapour such as absorption
by sulphuric acid. However larger volumes of vapour can be conveyed away out
of the cooling chambers or refrigerators under vacuum by purely mechanical means
by means of quickly revolving rotary pumps and centrifugal exhausters. The
rotary pump or exhauster also condenses the vapour exhausted from the vacuum
spaces so much that its originally very low temperature (being below the freezing
point) from the production of ice in the refrigerating apparatus is raised so much
that it can be thrown down by injecting water. The piston pump; therefore
(primary pump), the suction of which is connected to the delivery of the rotary
pump or exhauster, only requires to convey away the injection water and the air
led in with the same, as well as any air which may be drawn into the apparatus;
.9

page_text: it is therefore so arranged in this caso like the air pump of a steam engine
(condensation pump). A refrigerating machine constructed according to this
invention may be arranged as follows and consists of :-
.
A refrigerating chamber which is to be evacuated and into which water etc is
led, of which one part vaporises for cooling the rest in the vacuum.
A rotary pump or centrifugal exhauster the suction of which is connected to
the refrigerating chamber.
An injection chamber (condenser) into which the steam of the rotary pump is.
forced, and
A piston pump (condensing pump) the suction of which is connected to the
condenser and which conveys away the water and air from the refrigerating
machine.
It must however be remarked that the special construction of the rotary pump
or centrifugal exhauster used as secondary pump is of no importance for the
operation intended, these must however be so arranged that no outer air can
penetrate therein, the barrels must therefore be quite air tight and the spindles
must be provided with stuffing boxes.

page_text: A System or Combination of Pumps for Producing Vacuum.
I PETER JENSEN, Fel. Inst. P.A of 33 Chancery Lane in the County of Middlesex
do hereby declare the nature of this invention (a communication to me from abroad
by Ludwig August Riedinger of 25 Eisenhammer strasse Augsburg Germany.
Manufacturing Engineer) and in what manner the same is to be performed to be
particularly described and ascertained in and by the following statement:-
In simple piston pumps a vacuum of only about 10 m/m of mercury is attained
in closed spaces; this is even then the case when water is injected into the pump
cylinder in order to fill the detrimental spaces and in order to attain a better
packing of the piston, because it lies in the nature of the thing, that then the
limit of the rarefaction aimed at, is at the pressure of steam of the temperature of
the water injected. A greater vacuum may be attained if a second and namely
a dry pump is inserted between the space to be exhausted and the injector (first
pump) which second pump whilst its suction pipe is connected to the space to be
exhausted, its delivery force pipe is connected to the injector pump, between the
first and the second pumps a difference of pressure is produced, which may be
perceived by a further increase of the vacuum in the closed space. Up till the
present time two piston pumps have been used in combination with each other for
the described purpose and in the manner intimated.
A rotary pump or centrifugal exhauster may however be used as secondary or
inserted pump in combination with a primary pump, namely a dry piston pump or
one running with injection in the sense of the above statement and this application
forms the subject of the present invention.
By the combination of a piston pump with a rotary pump or a centrifugal
exhauster in such a manner, that the pressure space of the rotary pump or the
centrifugal exhauster forms the suction space of the piston pump, a greater vacuum
is also attained as by the combination of two piston pumps, but as against this
known arrangement the new combination is advantageous in such case, in which
chemical or physical processes are to be effected in a vacuum by which processes.
large volumes of gas or vapour are generated, which must be carried off out of the
chamber for the maintenance of the vacuum.
But piston pumps are no longer sufficient for exhausting several thousand cubic-
meters of gas per hour; on the other hand such volumes of gas or vapour may
easily be drawn out by means of a rotary pump or centrifugal exhauster, if the
pressures are not great-a condition which is fulfilled by using rotary pumps or
centrifugal exhausters as secondary in the manner above described, because only
a small difference in the pressure obtains between the vacuum space and the suction
space of the primary pump.
This difference of pressure namely depends upon the circumstance in what
relation the sizes of the combined pumps are to each other. If the alteration of
pressure of the conducted gases follows according to the Law of Mariotte, then the
capacity of the primary pump must be to that of the secondary pump as the
pressure in the exhausted space (suction space of, the secondary pump) is to the

page_text: pressure in the suction space of the primary pump (pressure space of the secondary
pump). If it is not possible by means of one rotary pump or one centrifugal
exhauster to condense the gas exhausted from the vacuum space so far, that à
piston pump of the size adapted for the conduction of the saine to the outer air
suffices it is only necessary to insert two or more behind each other and between
the piston pump and the vacuum space in such a manner that the pressure or
delivery space of one pump forms the suction space of the next, so that an increase
of pressure and decrease of volume of the separated gas or vapours takes place
from pump to pump. It is therefore possible under all conditions so to arrange
the differences of pressure of a single pump according to the requirements and
lastly a rotary pump or centrifugal exhauster may be used as the primary pump
instead of a piston pump.
With such gases which condense on contact with liquids, such for instance as
steam on the injection of water into the steam space, such a condensation is inserted
between the primary and secondary pump. The latter then only requires to deliver
the condensation fluid augmented by the product of condensation and the air which
may be carried into the condenser, and therefore only be able to attain a very
much smaller bulk, than if it had conducted the gas led to it from the second
pump itself.
Instead of using a piston pump here as condenser pump (primary pump) a pump
of any suitable construction may be used (such as a jet pump, rotary pump etc.).
If for instance water or a salt solution should come into the rarefied space, part
of the water forms steam and hereby takes up heat whereby the remaining portion
is more or less cooled under certain circumstances forming ice.
But as the steam produced has a great specific volume by an extremely small
pressure and it is therefore necessary by a considorable production of cold for such
vacuum cooling or refrigerating apparatus to convey away such large volumes of
vapour out of the cooling chambers or refrigerators under vacuum, piston pumps
because of their immense dimensions are not practically of use.
Other means have
therefore been resorted to for the removal of water vapour such as absorption by
sulphuric acid. However larger volumes of vapour can be conveyed away out of
the cooling chambers or refrigerators under vacuum by purely mechanical means
by means of quickly revolving rotary pumps and centrifugal exhausters. The
rotary pump or exhauster also condenses the vapour.exhausted from the vacuum
spaces so much that its originally very low temperature (being below the freezing
point) from the production of ice in the refrigerating apparatus is raised so much
that it can be thrown down by injecting water. The piston pump therefore
(primary pump), the suction of which is connected to the delivery of the rotary
pump or exhauster, only requires to convey away the injection water and the air
led in with the same, as well as any air which may be drawn into the apparatus;
it is also so arranged in this case like the air pump of a steam engine (condensation
pump). A refrigerating machine constructed according to this invention may be
arranged as follows and consist of:-
A refrigerating chamber which is to be evacuated and into which water etc is
led, of which one part vaporizes for cooling the rest in the vacuum.
A rotary pump or centrifugal exhauster the suction of which is connected to the
refrigerating chamber.
An injection chamber (condenser) into which the steam of the rotary pump is
forced, and
A piston pump (condensing pump) the suction of which is connected to the
condenser and which conveys away the water and air from the refrigerating
machine.
It must however be marked-that the special construction of the rotary pump or
centrifugal exhauster used as secondary pump is of no importance for the operation
intended, these must however be so arranged that no outer air can penetrate therein,
the barrels must therefore be quite air tight and the spindles must be provided with
stuffing boxes,
•

page_text: Having now particularly described and ascertained the nature of this invention
and in what manner the same is to be performed I declare that what I claim as
the invention communicated to me is
First. The serial combination of rotary pumps or centrifugal exhausters with a
piston pump in the described manner for the purpose, with such a combination
'pump in closed spaces to produce and maintain a stronger vacuum than it is
possible with a single pump alone.
Second.. The combination of rotary pumps or centrifugal exhausters with a
piston pump or a rotary pump or any other pump and a, condenser inserted in the
manner described for the purpose by means of such a combination pump in
combination with the condenser to produce and maintain by purely mechanical
means a strong vacuum in such spaces in which in consequence of chemical or
physical processes large volumes of condensable gases are produced.