Improved Arrangements of Machinery for Operating the Pistons of Vapour Pumps employed in Ice Making or Refrigerating Apparatus.
Year: 1893

page_text: Date of Application, 7th Sept., 1893
Complete Specification Left, 7th June, 1894-Accepted, 7th July, 1894
PROVISIONAL SPECIFICATION.
Improved Arrangements of Machinery for Operating the Pistons
of Vapour Pumps employed in Ice Making or Refrigerating
Apparatus.
I, PHILIP ELIOT HODGKIN, of 63 Queen Victoria Street, in the City of
London, Engineer, do hereby declare the nature of the said invention to be as
follows:-
In vapour pumps employed for compressing the gases of volatile liquids, such
as ammonia, carbonic acid, sulphurous acid and such like, in machinery for making
ice or for refrigerating, it is important that there shall be as little clearance as
possible between the piston and the cylinder covers at the end of each stroke.
In
some arrangements of such machinery the vapour pump is placed tandem, that is
in line with the steam cylinder, the tail rod of the latter being coupled direct to
the front end of the vapour pump piston rod. In this arrangement there is some
little danger of the expansion of the piston rods by the heat of the steam and of
compression of the vapour causing the pump piston to strike the rear cover but
it is generally practicable to so adjust the length of the rods and the clearance as
to avoid that danger without necessitating an excessive amount of clearance; but
when the vapour pump is placed tandem with a tandem compound steam engine,
that is with the three cylinders in line, the three piston rods coupled end to end
become so long that their expansion by the heat of the steam and compressed
vapour is liable to be so great that the clearance in the pump has to be increased
to an inconvenient extent, and the object of my present invention is to provide
such an arrangement of the steam cylinders and pump as will obviate this
inconvenience as well as that of the excessive length of the machinery entailed by
tandem arrangement when the cylinders are placed in line.
For this purpose I place the high and low pressure steam cylinders side by side,
but at a short distance apart, and behind these cylinders and in line with the space
between them, I place the vapour pump. The front ends of the high and low
pressure steam piston rods are connected together by a strong, crosshead which is
guided by any suitable guides, and is connected to the crank shaft by one or more
connecting rods and cranks in the usual way.. To a suitable point of the aforesaid
crosshead, between the high and low pressure steam piston rods, is secured the end
of the piston rod of the vapour pump which passes from the stuffing box of the
pump through the space between the two steam cylinders.
By these means the piston rod of the vapour pump is kept independent of the
steam piston rods and remains always unaffected by their expansion and contraction
lengthwise, and a considerable.saving in the length of the machinery is also thereby
effected.
In some cases the feed, circulating water, and air pumps, may be placed in lipe
with the front ends of the steam pistons so as to be operated direct by them.
Dated this 7th day of September 1893.
!

page_text: Improved Arrangements of Machinery for Operating the Pistons
of Vapour Pumps employed in Ice Making or Refrigerating
-Apparatus.
.
I, PHILIP ELIOT HODGKIN, of 63 Queen Victoria Street, in the City of
London, Engineer 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, that is to say :-
In vapour pumps employed for compressing the gases of volatile liquids, such as
ammonia, carbonic acid, sulphurous acid, and such like, in machinery for making
ice or for refrigerating it is important that there shall be as little clearance as
possible between the piston and the cylinder covers at the end of each stroke. In
some arrangements of such machinery the vapour pump is placed tandem, that is
in line with the steam cylinder, the tail rod of the latter being coupled direct to
the front end of the vapour pump piston rod. In this arrangement there is some
little danger of the expansion of the piston rods by the heat of the steam and of
compression of the vapour causing the pump piston to strike the rear cover, but
it is generally practicable to so adjust the length of the rods and the clearance as to
avoid that danger without necessitating an excessive amount of clearance; but when
the vapour pump is placed tandem with a tandem compound steam engine, that is
to say with the three cylinders in line, the three piston rods coupled end to end
become so long that their expansion by the heat of the steam and of the compressed
vapour is liable to be so great that the clearance in the pump has to be increased
to an inconvenient extent, and the object of my present invention is to provide such
an arrangement of the steam cylinders and pump as will obviate this inconvenience
as well as that of the excessive length of the machinery entailed by the tandem
arrangement when three cylinders are placed in line.,
For this purpose I employ the arrangement shown in the accompanying drawing
which is a plan of a compound steam engine and compression pump arranged in
accordance with my invention. A and B are respectively the high and low
pressure steam cylinders which I place side by side, but at a short distance apart;
and behind these cylinders, and in line with the space between them, I place the
vapour pump C. The front ends of the, bigh and low pressure steam piston
rods A'B' are connected together by. a strong crosshead D which is guided by any
suitable guides such as those shown at E E for example, and is connected to the
crank shaft F by one or more connecting rods G in the usual way. To a suitable
point of the aforesaid crosshead between the high and low pressure steam piston
rods is secured the end of the piston rod H of the vapour pump C, which rod
passes from the stuffing box C₁ of the pump C through the space between the
two steam cylinders.
In the arrangement shown in the drawing the valve chests A'B' of the steam
cylinders are placed on top of the cylinders, and so as to span over the space
between the two cylinders through which the rod H passes but it is obvious that
the said valve chests may be arranged in any other suitable and convenient way
according to circumstances.
In the above description the two steam cylinders A and B are referred to as the
high and low pressure cylinders respectively of a compound engine, but it is
evident that they may each be the cylinder of a simple engine if preferred.
By these means the piston rod H of the vapour pump C is kept independent of
the steam piston rods A' B' and remains always unaffected by their expansion and
contraction lengthwise, and a considerable saving in the length of the machinery is
also thereby effected.

page_text: In some cases the feed, circulating water, and air pumps may be placed in line-
with the front ends of the steam piston rods so as to be operated direct by them as-
shown for example at I in the drawing.
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.
First. The improved arrangement of machinery for operating the piston of a.
vapour pump in ice making or refrigerating machinery, which consists in placing
the steam cylinders side by side with a space between them, placing the vapour
pump behind and in line with such space, passing the piston rod of the vapour.
pump through such space, and connecting the steam engine and vapour pump.
piston rods to one crosshead, substantially as described and illustrated in the
drawing.
Second. The improved arrangement of machinery for operating the piston of a.
vapour pump in ice making or refrigerating machinery substantially as described.
Dated this Sixth day of June 1894.
P. E. HODGKIN,
Per W. H. Beck,
Agent.