Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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This invention pertains to gas compressor units,
and in particular to multi-stage, axial-flow gas com-
pressors having gas cooling and demisting means in-
corporated therewith.
Prior art gas compressor units of the aforesaid
type to which the invention pertains typically have
gas cooling means which cause the product gas to:
(1) follow serpentine flow paths, (2) be piped out
to a separate cooler or heat exchanger, or (3) be
conducted through considerably axially-extended
coolers or heat exchangers. Exemplary of the first
type are U.S. patents Nos. 2,925,954, issued to
W. Spillmann et al., for a "Compressor Group with
Intercooler", on 23 February 1960, and 912,882, issued
to O. P. Oraker, for an "Air Compressor", on 16
February 1909. U.S. patent No. 2,478,504, issued to
R. Ruegg, for a "Plant for the Production and Heating
of Compressed Air7', on 9 August 1949, ls typical of
the aforesaid second type. U.S. patent No. 2,073,833,
20 issued on 16 March 1937, to G. DeBothezat, for an
"Air Conditioner", discloses an axially-extended
cooler, of the third, aforesaid, prior art type,
having a length equal to, or greater than the total
length of the compressor stages which deliver gas
thereto. This is true of the Spillmann et al. dis-
closure also.
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All the aforesaid types, due to the configurations,
dimensions, and fluid-flow conductances thereof, mani-
fest a significant pressure drop through the coolers
or heat exchangers.
Now, patently, the optimurn gas compressor unit
should conduct all gas flow therethrough only substan-
tially axially, to prevent undue pressure drop. To
this end, then, it is necessary to have considerably
axially-extended coolers and intercoolers, and conduct
the gas product therethrough unidirectionally. Un-
fortunately, however, such coolers and intercoolers
of considerable length subject the product gas to
pressure losses; these occur due to the relatively
long residence time for the gas flow to negotiate the
length of the coolers, and the turbulances, eddies,
and friction arising therefrom.
Well, external piping of the product gas to
separate coolers will not prevent the pressure drop,
and coaxially linear, unldirectional coolers, having
2~ appreciable length to insure adequate residence time
and a resulting efficient cooling appears to be the
only option available. The undue pressure drop pro-
ceeding therefrom is not avoidable. Thus is the
state of the art. However, I have discovered that
there does obtain another, heretofore not recognized
option. I have conceived a gas compressor unit which
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will efficiently cool the product gas and will not
cause a pressure drop across the intercoolers and
demisters in excess of approximately one p.s.i. It is
my object to disclose such a gas compressor unit.
It is particularly an object of this invention to
set forth a gas compressor unit, for compressing gas to
a pressure taken from a range of pressures of from
approximately seventy-five to approximately one hundred
and fifty p.s.i~, comprising a plurality of serially-
arranged, multi-staged, axially flow gas compressors; gas
intercooling and demisting means; and means coupling said
intercooling and demisting means interpositionally
between said compressors of said plurality thereof; said
coupling means and said intercooling and demisting means
comprising structure having such configuration, dimensions
and fluid-conductance as to prevent a pressure drop9
across said intercooling and demisting means, of
- compressed gas conducted therethrough, of more than
approximately one p.s.i.
According to the above objects, from a broad
aspect, the present invention provides a gas compressor
unit for compressing gas to a pressure taken from a
range of pressures from approximately seventy-five to
one hundred and fifty p.s.i. The compressor unit
comprises a plurality of serially-arranged-multi-staged,
axial-flow gas compressors. Gas intercooling and
demisting means of annular configuration are also
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p.rovidedO Means is provided for coupling the inter-
cooling and demisting means interpositionally between
the compressors. The coupling means and the inter-
cooling and demisting means comprises structure having
such configuration, dimensions and fluid-conductance
as to prevent a pressure drop, across the intercooling
and demisting means 9 of compressed gas conducted
therethrough, of more than approximately one p.s.i.
The.unit has a gas inlet capacity of at least one
hundred thousand cubic feet a minute. The intercooling
and demisting mean.s has an outside diameter of at least
a given dimension, and an axial length of not more than
twenty-five percent of the given dimension.
Further objects of this invention, as well as the
novel features thereof 9 will become more apparent 9 by
reference to the following description, taken in
conjunction with the accompanying Figures, in which:
Figure 1 is a side elevational view of an embodiment
of the invention:
Figures 2A and 2B comprise an axial, cross-
sectional view, in elevation, of the Figure 1 embodiment
of the invention, the same being enlarged over the
scale of Figure 1: and
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Figure 3 is a fragmentary, cross-sectional view of
one of the intercoolers, taken along section 3-3 of
Figure 1, the same being considerably enlarged over the
scale of Figure 1.
As shown in the figures, an em~odiment of the novel
gas compressor unit 10, comprises first, second, and
third multi-stage, axial-flow compressors 12, ].4, and
16, respectively, serially arranged, and joined through
a common drive shaft assembly 13. Intercoolers 20 and
22 and demisters 24 and 26 are lnterpositioned between
the compressors. The unit 10 is supported by stanchions
28, 30, 32 and 34, and has a first stage wheel 36 having
a diameter which, in this embodiment, is of approximately
sixty-four inches in dimension.
Intercoolers 20 and 22 and demisters 24 and 26 are
almost two hundred and sixty per cent larger than the
diameter of the first stage wheel 36, as they have
diameters of approximately one hundred and sixty-four
inches.
Compressor 12 has an exit annulus 40 which encom-
passes approximately seven square feet of area, and the
intercooler 20 has an entry annulus 42 which encompasses
approximately one hundred and forty-three square feet
of area. Hence, the latter area is approximately twenty
times greater than the former area. The exit annulus
40' of compressor 14 occupies an area of approximately
four and a half square feet. Accordingly, the entry
annulus 42' of intercooler 22 is approximately thirty-
two times larger than annulus 40'.
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Notwithstanding the considerable diameters of inter-
coolers 20 and 22, they occupy not more than one-third
the total axial length of the stages of the respective
compressors 12 and 14. That is, while the stages' total
axial length of compressor 12 is approximately one hun-
dred and four inches, the intercooler 20 is only approxi
mately twenty-six inches in axial length. The demisters
24 and 26 are only approximately nine inches in axial
length; i.e., they have a length of about five and a
half per cent their diameter. The intercoolers have a
length of about sixteen per cent of their diameter.
Such short length intercoolers 20 and 22, and de-
misters 24 and 26, insure that the residence time or
confinement of gas therewithin will be exceedingly brief.
Thereby, the incidence of turbulence, eddies and friction
is markedly reduced and the pressure drop, across the inter-
coolers and demisters, does not exceed approximately one p.s.i.
While it may seem that such short-length inter-
coolers 20 and 22 cannot have adequate capacity for gas
cooling, in fact they are novelly designed for such.
Each has a gross capacity of almost one hundred and
forty-three cubic feet. Within this total volume are
a multiplicity of finned heat exchanger tubes 44. In
this embodiment 10, approximately sixty-eight hundred
and fifty tubes 44 are employed. They accommodate a
product gas capacity of slightly more than one hundred
and fifty cubic feet, while the coolant-water channels,
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which the tubes 44 traverse, accommodate a capacity of
slightly more than one hundred and forty cubic feet.
The intercoolers 20 and 22 are identical in struc-
ture, so the fragmentary depiction in figure 3 is ex-
emplar~ of both. The tubes 44 are held at either endsin side plates 46 and 48, and a peripheral wall 50
sealingly circumscribes the plates. ~he wall 50 is
replaceably bolted, through flanges 52 and 54, to an
intercooler inlet diffuser 56 and an outlet plenum 58.
In the lower portion of the wall 50 are formed water
inlet and discharge ports (not shown) which admit
coolant water to a first section 60 of the intercooler
and discharge it from a second section 62. A pump 63
supplies the water, providing a flow through the inter-
cooler at a velocity of slightly more than five feet
of flow a second between the tubes 44. A barrier plate
64, which subdivides the intercooler into the aEoresaid
sections, has a termination 66 at the top to allow the
sections to communicate thereat.
Gas-product flow through the intercoolers 20 and
22 is linear, unidirectional, and axial. The generous
expanse of the entry annuli 42 and 42' accommodates the
Eull discharge of the exit annuli 40 and 40', subdividing
the flow into the aforesaid approximately sixty-eight
hundred and fifty tubes 44 for efficient cooling in a
short axial travel. The approximately sixty-eight
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hundred and fifty discrete streams of product-gas are
uniformly addressed to the large-diameter demisters 24
and 26, thereafter. Due to this wide dispersion of the
product-gas into such a multiplicity of separate streams,
no areas of the demisters are more burdened than others
thereof. Hence, the demisters 24 and 26, although ex-
periencing rapid through-flows of the gas -- due to the
extremely short axial extent of the demisters -- knock
out approximately ninety-eight per cent of the moisture
content (of 13 microns and larger).
The unit 10 is designed for facile maintenance, in
that the whole outer shell therof is horizontally split.
. .
The upper half of the inlet throat 37, the upper half
of the diffuser 5~, and the therebetween upper half of
the shell of compressor 12 can be unbolted together
from the corresponding lower halves, and from the ad-
jacent upper half of intercooler 20, and lifted orf
in one piece. This is shown, in phantom, in Figure 1.
Also, the intercooler 20 (or 22) can be unbolted from
the adjacent diffuser 56 and plenum 58 and lifted out
for servicing and/or replacementO The throat 37, or
upper and lower halves of diffuser 56, or halves of
plenum 58, or halves of the compressor shell may be
removed and replaced at will.
The most si~nificant teaching herein, however, is
the structuring of an axial-flow gas compressor unit
with gas coollng and demisting means which suffers not
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more than a one p.s.i. pressure drop across the inter-
coolers and demisters, and in which the cooling and
demisting means add insignificant axial length. Pur-
suant to my disclosure herein, t:he latter have pre-
scribed areas and volumes efficiently to process theproduct gas without diminishing the optimum performance
of the unit 10, and the invention comprehends a speci-
fied flow of coolant water through the sections of the
intercoolers. A]l said features of my conception and
calculation define an exemplary embodiment of the in-
vention which teaches the art a new option in multi-
stage, axial-flow gas compressor design.
The embodiment 10 shown comprises a unit configured
to deliver approximately three hundred thousand inlet
c.f.m. compressed to a product gas pressure taken from
a range of pressures or from approximately seventy-five
to one hundred and fifty p.s.i. However, the novel
teachings and structures can be used to define a units
delivering one hundred thousand to approximately six
hundred thousand c.f.m. within the aforesaid said
pressure range.
To apply the inventive teachings herein to define
units having capacities of from fifty or one hundred
thousand to approximately six hundred thousand c.f.m.
it is necessary to dimension the intercooler and de-
mister diameters accordingly. While doing this, however,
they must be maintained at their limited axial lengths
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of twenty-six and nine inches, respectively. Otherwise,
if the intercoolers and demis~ers are given greater
axial lengths, the units constructed therewith will
manifest a greater than one p.s.i. pressure drop acro.ss
the intercoolers and demisters.
Diameter sizing, then, of t:he intercoolers and de-
misters, while holding them to t:heir aforesaid lengths,
is fairly critical. It is a teaching of my invention
to use formulas of my conception to define acceptable
diameters. ~roadly, to determine the diameters for the
intercoolers and demisters for a unit having an inlet
capacity of from less than one hundred thousand cubic
feet a minute to approximately six hundred thousand
cubic feet a minute, I set forth ,the following foxmula:
the diameter shall be 1.15~inch, approximately, times
each 1000 c.f.m. of inlet capacity, to an inlet capacity
of approximately 100,000 c.f.m., plus 0.25-inch, approxi-
mately, times each increment of 1000 c.f.m., of inlet
capacity, which is in excess of 100,000 c.f.m. More
definitively, the diameter shal] be l.lS-inch, approxi-
mately, times each 1000 c.f.m. of inlet capacity, to an
inlet capacity of approximately 100,000 c.f.m., plus not
less than 0.21-inch and not more than 0.28-inch, times
each increment of 1000 c.f.m., of inlet capacity, which
is in excess of 100,000 c.f.m.
Such formulae determinations of intercooler and de-
mister diameters will prescribe intercoolers having
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diameters which are from four and a half to nine times
greater than their twenty-six-inch axial lengths, and
demisters having diameters which are from twelve and a
half to twenty-six times greater than their nine-inch
axial lengths. However, as unconventional as this
teaching may be, it provides gas compressor units of
serially-arranged, multi-staged, axial flow compressors
having a pressure drop, across the intercoolers and
demisters, of not more than approximately one p.s.i.,
and accommodating gas flow into such intercoolers and
demisters at a velocity of not more than approximately
twenty-two feet per second.
Typically, multi-staged, axial-flow, gas compressor
units, having intercooling ~and demisting) means have
the intercoolers set apart from the axis of the units,
and the compressed ga.s product must be conducted thereto
and therefrom. This prior art practice was cited earlier
in this specification. Now, it is further a typically
required practice to mount the intercoolers on mezzanine-
type supports, or in below-flow-level bays. Accordingly,
the installation structures and requirements for such
units are both complex and expensive. My novel gas com-
pressor unit, however, comprises a plurality of com-
pressors and intercoolers all serially-arranged in a
single-axis alignment, on stanchions. Therefore, my
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inventive unit can be, and is intended to be, floor-
mounted, fully, from end-to-end. Too, as can be appre~
ciated from the foregoing, the in-line coolers and de-
misters do not contribute, signi.ficantly, to the over-
all lenyth of the unit. Each interstage set of inter-
cooler and demister (excluding entry and exit plenums
or shrouds) add less than three feet to the unit length.
This remains so, whether the unit is configured to de-
liver one hundred thousand or six hundred thousand cubic
feet a minute. For greater capacities, within the afore-
said range, it is only necessary to increase the inter-
cooler and demister diameter according to my disclosed
formulae.
While I have described my invention in connection
with a specific embodiment thereof, it is to be clearly
understood that this is done only by way of example and
not as a limitation to the scope of my invention as set
forth in the objects thereof and in the appended claims.
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