Improvement in Apparatus for Compressing Gas or Gaseous Bodies.
Year: 1888

page_text: Improvement in Apparatus for Compressing Gas or Gaseous Bodies.
I, LOUIS BLOCK of No. 156 West 95th Street, in the City and State of New York,
United States of America, Mechanical 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:-
My invention is applicable to that class of compressors in which oil, water, etc., are
mingled in the compressor with the gas or air etc.; and the, improvement relates to
means for ejecting surplus oil, water, etc., from compressors and for cooling said oil,
water, etc., prior to its return to the compressors.
I prefer to use in my apparatus gaseous ammonia and oil derived from petroleum,
and will henceforth speak of such gas and such oil although I intend to use the
apparatus for compressing common air or any gas, and to supply the compressor with
water, glycerine oils or other suitable liquids which will fill the clearances, and to a
greater or less extent lubricate the parts and liquid seal the valves and packings.
It has been known for many years that clearances in gas compressors may
be filled
with oil, so that the piston although it does not touch the cylinder heads at the ends
of its strokes will discharge all the compressed gas. In order to perform this duty
effectively, oil must be supplied to the cylinder at each end thereof (if double-acting)
at some time after the piston leaves one cylinder head and before it returns again to
that same cylinder head, and the quantity of oil in the cylinder is a little in excess of
that absolutely necessary to fill the clearances, consequently oil is expelled at each
stroke. If the piston should strike such oil in excess after the delivery valves are
shut, or after the piston has passed and closed the delivery ports, thus preventing the
escape of oil, either the piston or the cylinder head would give way if the engine and
momentum of the fly-wheel were forcible enough to keep the piston moving, and
they generally are sufficiently forcible to produce this effect.
The first part of my invention is designed to obviate this difficulty, and is peculiarly
applicable to the lower ends of vertical double-acting compressors, although it may
be usefully employed in connection with the ends of horizontal compressors, either
single or double-acting, or to the lower ends of vertical single-acting compressors,
which compress gas on the down-stroke thereof. The drawings show at Figure 1, an
elevation of certain parts of a refrigerating apparatus, the steam. engine which
actuates the compressor at X, the compressor at H, the condenser at W, the oil
cooler at T

page_text: Figure 2. is partly in elevation and partly in section on a larger scale, and
represents the oil cooler and the passages for oil and gas.
Figure 3. is also on a larger scale than Figure 1, and is a section through a double-
acting vertical compressor and some of its connections and valves. This compressor
may have any proper kind of discharge valve or valves at its upper end, such as the
large valve C, and is provided with at least two induction valves, one at each end,
A and B, of any usual variety. The large discharge valve lies on a seat at the lower
end of a head or dome, and from this dome leads the discharge pipe E, H³. This
pipe extends to the lower end of the compressor, and has opening into it the two
lower discharge valves D¹, D². There must be at least two of these valves with their
ports one above the other, but there may be several of them in rows, with the ports
of one row leading into the cylinder above those of the other row.
The ports of
these delivery valves where they enter the cylinder may be provided with helical ribs,.
flush with the interior or bore of the cylinder so as to prevent injury to the packing-
ring when it travels over the ports. From the discharge pipe a branch H leads to
carry off the oil and compressed gas. So far, all parts except the duplication of the
exhaust valves at the lower end of the compressor may be and are, in fact, as usual in
double-acting pumps. The piston is composed of two parts, with a space or chamber
between them. These two parts may be affixed to the piston-rod, and held apart so
as to leave a space between them in any proper way, and cach part must be provided
with ordinary packing or packing-rings. This chamber is open to the inner walls of
the cylinder. In the lower part of the piston there are one or more valve-seats cach
provided with a valve, such as M, opening upwards, and preferably provided with
a light spring tending to seat it quickly. These valves when lifted or open connect
the space below the piston as a whole with the chamber between the two parts of the
piston.
The valve D² is located slightly above the lower head of the compressor, the lowest
part of its port is also above this head. The thickness of the lower part of the piston
is so proportioned to the distance between the two ports of the valves D1 and D2 that
the upper port is uncovered by this part of the piston in its descent before the lower
port is closed by it. The part of the compressor cylinder below the lower exhaust
valve port is in the operation of the machine filled with oil. The upward bend of the
induction pipe prevents this oil flowing out on the upstroke of the piston. When
the piston in its descent has compressed the gas in the cylinder. to such extent that the
exhaust valves open, compressed gas flows out through both valves. When the lower
part of the piston closes the port of the upper valve, gas goes out of the lower valve.
When the lower part of the piston in its continued descent uncovers the port of the
upper valve gas and probably some oil may pass out through both valves. When
the lower part of the piston closes or partly closes the port of the lower valve and
strikes the oil, then oil and gas, or oil alone, lift the valve or valves in the piston,
flow into the space or chamber between the two parts of the piston, and thence
into the discharge-pipe through the upper exhaust valve, the pipe of which is then
uncovered by the lower part of the piston, before that lower part closes or covers
the port of the lower exhaust valve. The upper part of the piston is located so far
above the lower part that it will not cover the upper exhaust port until the piston
has completed its down stroke, or it may not cover it even then. It will thus appear
that when the piston strikes against the oil there will always be an outlet open for
excess of oil to flow out of the pump, consequently all danger of knocking out the
the head is obviated, and further the construction is such that the oil will always
remain below the piston filling the clearance space.
Oil must in a double acting pump be constantly or at sometime during each stroke
supplied to each end of the cylinder. This oil in the pump shown in the drawings
enters through the holes ¹² and may be supplied by any usual means at any usual
or proper time. The easiest way is to supply it from a reservoir under pressure
through a cock or measuring apparatus.
.
The second part of my invention consists in a new method of cooling the oil
discharged from the compressor and before it is returned thereto. The mingled oil

page_text: and gas are delivered from the exhaust pipe into the vessel 1. The oil is hot. The
oil and compressed gas separate in this vessel mechanically. The oil drops to the
bottom; the gas rises to the top and passes out through the pipe I¹ to the condenser ;
this gas is cooled in the condenser and liquefies; this liquid is then admitted to the
expansion coils; there it expands again into gas and absorbs heat, refrigerates air,
brine, etc. This gas does not usually absorb all the heat it is capable of absorbing in
the expansion coils.
I take advantage of this fact, and instead of leading the expanded gas directly to
the compressor to be recompressed as usual, force it or part of it to pass through
pipes or tubes enclosed in the separating tank. These tubes are shown at i, i, i. The
pipe P is the pipe which conducts the gas from the expansion coils, and the whole or
part of this gas can pass through the valve J, thence up through the tubes i, i, i,
thence through the valve J³ into the pipe P, and thence to the induction valves of
the pump. Or by closing or partly closing the valves J2, J³, or either of them, and
opening the valve J, the whole or a part of the expanded gas may be passed through
the pipe J into P¹, and thence to the pump or compressor.
This expanded gas passing in pipes through the oil robs it of its heat, cools the oil,
and the amount or degree of cooling can be regulated to a certain extent by passing
a greater or less proportion of the whole amount of gas through the pipes i, i, i, as
before described.
Any kind of tank may be used that will serve as a separator for oil and gas, and
the expanded gas might flow in a jacket around the oil instead of through the oil in
pipes. Such a jacketed vessel is common, and needs no special description or
drawing.
All who have made a study of processes of refrigeration agree that the oil should be
cooled after leaving and before it is returned to the compressor. It can be cooled to
a low temperature by my method, and expenditure of water for cooling purposes is at
the same time avoided.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed declare that what
[ claim is
1. A piston with a close-topped chamber therein provided with valves opening into
the chamber so that the oil when struck by the piston can lift the valves and enter
the chamber and be prevented from returning, the construction being substantially
such as described.
2. A piston with a space or chamber therein, and a valve or valves opening into
such chamber, in combination with an exhaust port, and valves so located substantially
as described that oil or gas passing through the piston valve or valves into the
chamber may be discharged through such exhaust port and valve, the construction of
the whole being substantially such as herein described.
3. In combination, first, a piston with a chamber therein; second, valves in the
piston opening into said chamber; third, an upper exhaust port and valve communi-
cating with said chamber, and fourth, a lower exhaust port and valve, all these ports
being constructed, arranged and operating substantially as described.
Dated this 20th day of September 1888.
LOUIS BLOCK.