IMPROVED MEANS AND APPARATUS FOR PREVENTING THE ESCAPE OF VOLATILE FLUIDS FROM THE STUFFING BOXES OF COMPRESSION PUMPS
Year: 1884

page_text: I, CHARLES DENTON ABEL of N° 28. Southampton Buildings, Chancery Lane,
in the County of Middlesex Consulting Engineer and Patent Agent do hereby
declare the nature of the said Invention for "IMPROVED MEANS AND APPARATUS
FOR PREVENTING THE ESCAPE OF VOLATILE FLUIDS FROM THE STUFFING BOXES
OF COMPRESSION PUMPS" and in what manner the same is to be performed to be
particularly described and ascertained in and by the following statement :-
In compression pumps such as are mainly used in refrigerating or ice making
machinery for compressing the volatile fluids employed, such as ammonia, methyl
ether &c., a great difficulty is experienced in preventing the escape of such fluids
through the stuffing boxes of the pumps. Heretofore, ineans have been employed
for preventing such escape, consisting in the use in the stuffing boxes of a non-
volatile liquid under pressure that is neutral either chemically only, or both
chemically and mechanically speaking in respect of the said volatile fluids, so
as, while preventing their escape into the open air, to possess no property for
either absorbing or otherwise acting on them.
According to the present Invention, a liquid is employed for the above purpose,
which, in a chemical sense, is neutral to the said volatile fluids, but which will
mecbanically absorb the same, by which means, the necessity for maintaining such
liquid under pressure in the stuffing box is obviated, as any volatile fluid that may
leak into the stuffing box will be absorbed by the said liquid from which it can be
afterwards regained.
For this purpose, there is connected to the stuffing box a receptacle, open to the
atn:osphere charged with the said chemically neutral but absorbent liquid, and
which I will term the absorption vessel, so that the liquid is supplied from such
vessel to the stuffing box, where it absorbs any escaping volatile fluid, until
the whole of the liquid in the vessel has reached a certain point below saturation,
whereupon the liquid is removed and the volatile Huid is regained therefrom by
distillation.
The liquid employed for the above purpose should be such as to possess the
greatest possible absorbing power for the volatile fluid in question and as it is

page_text: known that the absorbing power of liquids increases with the decrease of its
temperature, it is preferred to employ such liquids, as will only solidify at very
low temperatures while acting at the same time efficiently as lubricants.
A liquid which has been found to be particularly well adapted for this purpose
is the "oleo-naphtha" from Nischni-Nowgorod, which has a cold test of 10° Fahr.
This liquid is maintained by any known means at a suitable minus temperature,
so as to efficiently absorb all the volatile fluid that may leak through the ordinary
packing of the stuffing box, and before it attains the point of saturation it is
removed from the receptacle and replaced by fresh liquid.
This method of operating bas the farther advantage over that heretofore
employed that no loss of the volatile fluid takes place through the adhesion
of the said lubricating liquid to the piston rod as it passes out of the stuffing
box into the atmosphere, as such carrying out of the lubricant would only occur
to any appreciable extent when the lubricant exists under considerable pressure in
the stuffing box.
Figs. 1, 2, and 3 of the accompanying Drawings shew the construction of
apparatus which it is preferred to employ for carrying out the above described
method of operating. Fig. 1 shews the simplest arrangement. A is the open
absorption vessel, formed on the stuffing box B and containing any desired
quantity of the absorbant lubricating liquid, which flows thence into the stuffing
Lox, this being closed fluid tight by a gland at C, so as to prevent any leakage
of the lubricant. The stuffing box is also provided with the ordinary packing
material which is consequently saturated by the lubricant, so as to prevent leakage
past the piston rod. A branch pipe is provided at 1, through which-the-lubricant
can either-be-drawn-off-continuously, a continuous supply being in that case
fed into the vessel A, or the supply and discharge can be effected intermittently.
In this arrangement, it is a-sumed that the absorbant liquid is only maintained
at atmospheric temperature, no special means for refrigeration being provided.
Figs. 2 and 3 shew arrangements in which are provided means both for refrigerating
the liquid and for effecting a continuous circulation thereof, whereby the withdrawal
of the liquid more or less saturated with the volatile fluid, the separation of such
fluid from the liquid, and the return of the absorbant liquid to the stuffing box,
as also of volatile fluid to the compression apparatus is effected automatically.
In the arrangement at Fig. 2, A is again the absorption vessel and B the
ordinary stuffing box. The latter is in this case not formed in one with the
absorption vessel as in Fig. 1, the latter being formed on a separate stuffing box C
connected fluid tight at G with the stuffing box B. The saturated absorbant
liquid is continuously drawn off from the branch 1 by means of the pump P, the
stroke of which is made variable, while, at the same time, a corresponding quantity
of fresh refrigerated liquid is fed into the vessel A by the pipe 5. The cooling of
the liquid may also be effected in the vessel A itself by means of a refrigerating
coil 7, the refrigeration being conveniently effected by the evaporation in the coil
of a portion of the volatile fluid that is being used for the machine itself for
producing cold. The pump P conveys the absorbant liquid through the pipe 2
into the distilling apparatus D which may be of any suitable known construction,
and be heated either by the waste steam of the pumping engine or by fresh steam.
The liberated volatile fluid is drawn off through the pipe 3 communicating with
the suction pipe of the compressor, so as to be again supplied to the machine, while
the absorbant liquid freed from the volatile fluid is led off through the serpentine
pipe either situated in the freezing liquid of the generator or otherwise subjected
to cooling action, and is then conveyed back into the vessel A. If requisite, a
preliminary cooling may be effected by water before passing the liquid into the
refrigerating coil 4.
Fig. 3 shews another modification, in which the absorption vessel is divided into
an upper and a lower compartment A A¹ of which the lower one A has partitions
projecting alternately from opposite sides, causing the liquid to flow downwards
in a serpentine direction, the object hereof being to insure the perfect absorption
:

page_text: of the volatile fluid by the liquid, by causing them to remain in intimate contact
with each other as long as possible without requiring for this purpose to provide
a high column of liquid.
The open compartment A¹ is fixed upon and encloses the lower one, and the two
are made to communicate with each other by means of a pipe 6, so that the liquid
in the lower compartment will also be subject to only atmospheric pressure, leaving
extra pressure due to the column of liquid out of consideration.
The upper
compartment A¹ is supplied with absorbant liquid through tho ball cock S so as
to maintain the liquid at a constant level, and the liquid passes from the lower
part of this compartment through the pipe 6 into the lower compartiment. 7 is,
as before, a refrigerating coil by means of which the temperature of the absorbant
liquid can be reduced to any desired degree.
This arrangement offers the advantages over the preceding one of affording
greater security for the complete absorption of all the escaping volatile fluid and
of dispensing with attendance, the circulation of the liquid being rendered entirely
automatic by means of the ball cock.
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 is:―
:
First Preventing the escape of volatile fluids from the stuffing boxes of
compression pumps by the use of a lubricating liquid that is chemically neutral
in respect of the volatile fluid employed but that will absorb the same in a high
degree, such liquid being maintained at atmospheric pressure and either at
atmo pheric or a lower temperature, and being renewed when it arrives at a
certain point below saturation, substantially as herein described.
Second: The use, for preventing the escape of volatile fluids as set forth in the
preceding claim, of an open absorption vessel A for containing the absorbant liquid,
which is renewed therein either continuously or intermittently, substantially as
herein described.
Third The use, in combination with the absorption vessel A, referred to in the
preceding claim of a pump for withdrawing the absorbant liquid, a distilling
apparatus for separating the volatile fluid therefrom, and a refrigerating apparatus
for cooling the absorbant liquid to atmospheric or a lower temperature, substantially
as herein described.
Fourth: The use, in combination with the absorption vessel A of the pump P,
distilling apparatus D, and refrigerating pipe 7 within the vessel A, through which
pipe refrigerating fluid is made to flow, for maintaining the absorbant liquid at the
requisite low temperature.
Fifth Constructing the absorption vessel with two compartments A A¹
separated by a partition and connected by a pipe, the lower compartment A
being provided with partitions so arranged as to cause the absorbant liquid to
flow in a serpentine direction through the same, in order to remain as long as
possible in contact with the escaping gases, while the upper compartment A' is
provided with a ball cock on the supply pipe, in order to maintain the absorbant
liquid as nearly as possible at a constant level.
Dated this 2nd day of April 1884
ABEL & IMRAY,
Agents for the Applicant,
28, Southampton Buildings,
London, W.C.