U.S. patent application number 14/374965 was filed with the patent office on 2015-01-22 for volumetric screw compressor.
The applicant listed for this patent is Virgilio Mietto. Invention is credited to Virgilio Mietto.
Application Number | 20150023825 14/374965 |
Document ID | / |
Family ID | 46001613 |
Filed Date | 2015-01-22 |
United States Patent
Application |
20150023825 |
Kind Code |
A1 |
Mietto; Virgilio |
January 22, 2015 |
VOLUMETRIC SCREW COMPRESSOR
Abstract
The present invention concerns a compression device (1) suited
to compress a gas, of the type comprising: a main body (30; 130,
230; 330) suited to define a compression chamber (2) provided with
an inlet (32) for the gas; a liquid for compressing the gas, suited
to be injected in the compression chamber (2) to create a mixture
comprising the liquid and the gas; compression means (21, 22)
arranged in the compression chamber (2) and suited to compress the
mixture towards an outlet (50) of the compression chamber (2);
separation means (7), arranged downstream of the outlet (50),
suited to receive the mixture and to separate the liquid and the
gas that are included in the mixture; connection means (51) suited
to connect the outlet (50) to the separation means (7). Said
connection means (51) comprise at least one connection channel made
at least partially in said main body (30; 130, 230; 330).
Inventors: |
Mietto; Virgilio; (Creazzo,
IT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Mietto; Virgilio |
Creazzo |
|
IT |
|
|
Family ID: |
46001613 |
Appl. No.: |
14/374965 |
Filed: |
January 24, 2013 |
PCT Filed: |
January 24, 2013 |
PCT NO: |
PCT/IB2013/000088 |
371 Date: |
July 28, 2014 |
Current U.S.
Class: |
418/205 |
Current CPC
Class: |
F04C 2/16 20130101; F04C
18/16 20130101; F04C 2240/30 20130101; F04C 29/026 20130101 |
Class at
Publication: |
418/205 |
International
Class: |
F04C 2/16 20060101
F04C002/16 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 14, 2012 |
IT |
VI2012A000036 |
Claims
1) Gas compression device (1), comprising: a main body (30; 130,
230; 330) suited to define a compression chamber (2) provided with
an inlet (32) for gas, said main body being a single block; a
compression liquid for the gas, suited to be injected in the
compression chamber (2) in order to obtain a mixture comprising
said compression liquid and the gas; compression means (21, 22)
arranged in the compression chamber (2) and suited to compress the
mixture towards an outlet (50) of the compression chamber (2);
separation means (7) arranged downstream of the outlet (50) and
suited to receive the mixture and separate said compression liquid
from the gas included in the mixture; a connection channel (51)
suited to directly connect the outlet (50) to said separation means
(7); wherein said connection channel (51) is completely made in
said main body (30; 130, 230; 330).
2) Device according to claim 1, wherein: said separation means (7)
are at least partially housed in said main body (30; 130, 230;
330).
3) Device (1) according to claim 1 wherein: said separation means
(7) comprise an element (52) suited to convey said mixture against
a surface of said main body (30; 130, 230; 330).
4) Device (1) according to claim 1 further comprising: a tank (40)
arranged downstream of said separation means (7) in order to
receive at least a separated compression liquid of the mixture.
5) Device (1) according to claim 4, wherein: said tank (40) can be
removably associated with said main body (30; 130, 230; 330).
6) Device (1) according to claim 4 further comprising: a circuit
recirculating said compression liquid from said tank (40) to the
compression chamber (2).
7) Device (1) according to claim 6, wherein: said recirculation
circuit comprises an injection channel (47) for injecting said
compression liquid in the compression chamber (2), the injection
channel (47) being at least partially carried out in said main body
(30; 130, 230; 330).
8) Device (1) according to claim 6 further comprising: a
thermostatic valve (10) arranged along said recirculation circuit
of said compression liquid.
9) Device (1) according to claim 8, wherein: said thermostatic
valve (10) comprises a body (46) carried out in a single piece with
said main body (30; 130, 230).
10) Device (1) according to claim 6 further comprising: means (12)
for filtering said compression liquid are arranged along said
circuit.
11) Device (1) according to claim 10, wherein: said means for
filtering comprise a filter (12) that is housed in a supporting
seat (55) carried out in a single piece with the main body (30;
130).
12) Device (1) according to claim 1 further comprising: injection
means (3) for injecting the gas in the compression chamber (2).
13) Device (1) according to claim 12, wherein: said injection means
(3) comprise an intake valve (3) for the gas.
14) Device (1) according to claim 13, further comprising: a valve
body (31) of the intake valve (3), said valve body (31) being
carried out in a single piece with said main body (30).
15) Device (1) according to claim 1 further comprising: conveying
means (60), arranged downstream of said separation means (7), for
conveying a separated gas of the mixture to an oil separator filter
(13).
16) Device (1) according to claim 1 further comprising:
canalization means (49) for conveying said compression liquid for
lubricating moving parts of said gas compression device (1).
17) Device (1) according to claim 16, wherein: said canalization
means comprise one or more channels (49) made inside said main body
(30; 130, 230; 330).
18) Device (1) according to claim 1 wherein: said compression means
comprise two helical screws (21, 22) meshing with each other.
19. A gas compressor comprising: a main body; a compression chamber
formed in said main body having an inlet and an outlet; compression
means, placed within said compression chamber, for compressing a
mixture of a gas and a compression liquid, said compression means
moving the mixture to the outlet of said compression chamber; a
separator, whereby the gas and the compression liquid are
separated; and a connection channel completely made within said
main body coupled to the outlet of said compression chamber and
said separator, whereby the gas compressor has a reduced size and
weight with improved reliability.
Description
FIELD OF APPLICATION OF THE INVENTION
[0001] The present invention is related to the technical field of
the devices for the generation of compressed gas, preferably
compressed air.
[0002] In particular, the present invention concerns the technical
field of volumetric compressors.
[0003] In detail, the present invention concerns an oil-injected
volumetric screw compressor.
DESCRIPTION OF THE STATE OF THE ART
[0004] The use of devices for the generation of compressed gas is
known in several sectors, typically in the industrial field but
also in other fields.
[0005] These compressed gas generation devices, hereinafter simply
referred to as "compressors", are based on the intake of a gas,
typically air, and the treatment of the same to increase its
pressure while it flows towards an outlet.
[0006] The compressors of the known type are constituted by the
so-called oil-injected volumetric screw compressors.
[0007] Said compressors typically comprise a casing that defines a
compression chamber provided with a intake duct and a delivery
duct. Inside the compression chamber there are two helical rotors,
a male (generally driving) rotor and a female (generally driven)
rotor that mesh with each other. The compression chamber is fed
with oil and the air to be compressed. The compression of the
air-oil mixture takes place in the volume included between the
toothing of the two rotors and the casing. During the rotation of
the two rotors, the contact section included between the profile of
the male rotor and that of the female rotor shifts. More
particularly, said contact section shifts starting from the intake
duct towards the delivery duct. In this way, the air-oil mixture
included between the contact section and the delivery duct is
compressed.
[0008] The air-oil mixture flowing out of the compression chamber
is then subjected to a treatment to separate the oil from the
compressed air.
[0009] The separated oil is then recovered in order to be re-used
and re-introduced in the compression chamber.
[0010] The separation sector is thus arranged downstream of the
compression chamber.
[0011] According to the known art, the separation sector typically
comprises a tank. The oil particles are separated from the
compressed air due to a mechanical effect. The air-oil mixture
flowing out of the compression chamber is directed towards the tank
through a channel, typically a pipe. Inside the tank the separated
oil particles are deposited on the bottom of the tank, while the
compressed air remains in the upper portion of the same.
[0012] On the one hand, the oil is collected from the bottom of the
tank in order to recirculate it, as explained above, while on the
other hand the compressed air is collected from the upper portion
of the tank, further purified from any oil residues, and then made
available to be let out at the desired pressure.
[0013] The screw compressors belonging to the state of the art,
however, pose some drawbacks.
[0014] A drawback posed by the screw compressors of the known type
lies in their construction complexity that is due to the need to
channel the various flows along pre-determined paths, to feed oil
and air into the compression chamber, to convey the oil-air mixture
to the separation tank and to recirculate the oil.
[0015] First of all, this leads to a high production cost of the
various parts making up the compressor and to considerable assembly
time and costs.
[0016] Another drawback posed by said compressors and related to
their construction complexity is constituted by their limited
reliability which is due to the presence of several parts that may
get damaged over time.
[0017] This construction complexity also leads to the need for
complicated and costly operations for the maintenance and/or
replacement of any damaged parts.
[0018] A further drawback of said compressors is constituted by
their considerable overall dimensions, in particular due to the
size of the oil-air mixture separation tank.
[0019] Another drawback of said compressors is represented by
pressure drops along the channels of the oil, air and oil/air
flows, which reduce the overall efficiency of the compressor.
[0020] The main object of the present invention is thus to solve or
at least partially overcome the above mentioned problems that
characterize the volumetric screw compressors known in the state of
the art.
[0021] In particular, it is one object of the present invention to
provide a volumetric screw compressor that is more efficient than
the compressors of the known type.
[0022] It is another object of the present invention to provide a
volumetric screw compressor having reduced size and weight compared
to the compressors of the known type.
[0023] It is further object of the present invention to provide a
volumetric screw compressor that is more reliable than the
compressors of the known type.
[0024] It is another object of the present invention to provide a
volumetric screw compressor having reduced production and/or
maintenance times and/or costs compared to the compressors of the
known type.
[0025] It is a further object of the present invention to provide a
volumetric screw compressor that can be easily adapted to different
power ranges and/or to different needs in terms of overall
dimensions.
SUMMARY OF THE PRESENT INVENTION
[0026] The present invention is based on the general consideration
that the problems found in the art can be at least partially
resolved by providing a gas compression device that uses a
compression liquid, wherein one or more of the gas and/or liquid
conveying elements are integrated in a single block or main
body.
[0027] According to a first embodiment, the subject of the present
invention is thus a gas compression device of the type comprising:
[0028] a main body suited to define a compression chamber provided
with an inlet for said gas; [0029] a liquid for the compression of
said gas, suited to be injected in said compression chamber in
order to obtain a mixture comprising said liquid and said gas;
[0030] compression means arranged in said compression chamber and
suited to compress said mixture towards an outlet of said
compression chamber; [0031] separation means arranged downstream of
said outlet and suited to receive said mixture and separate said
liquid from said gas included in said mixture; [0032] connection
means suited to connect said outlet to said separation means,
wherein said connection means comprise at least one connection
channel created at least partially in said main body.
[0033] The separation means are preferably housed at least
partially in the main body.
[0034] According to a preferred embodiment of the invention, the
connection channel is completely made in the main body.
[0035] The separation means preferably comprise an element suited
to convey the mixture against a surface of the main body.
[0036] Advantageously, the device comprises a tank arranged
downstream of the separation means so as to receive at least the
separated liquid of the mixture.
[0037] According to a preferred embodiment of the invention, the
tank is suited to be removably associated with the main body.
[0038] Preferably, the device comprises a liquid recirculation
circuit running from the tank to the compression chamber.
[0039] According to an advantageous embodiment of the invention,
the recirculation circuit comprises a channel for injecting the
liquid in the compression chamber, wherein the injection channel is
at least partially made in the main body.
[0040] A thermostatic valve is properly arranged along the liquid
recirculation circuit.
[0041] According to a preferred embodiment of the invention, the
thermostatic valve comprises a body carried out in a single piece
with the main body.
[0042] Means for filtering the liquid are preferably arranged along
the liquid recirculation circuit.
[0043] According to a preferred embodiment of the invention, the
liquid filtering means comprise a filter that is accommodated in a
supporting seat carried out in a single piece with the main
body.
[0044] The device preferably comprises means for injecting the gas
in the compression chamber.
[0045] Advantageously, the injection means comprise a gas intake
valve.
[0046] In a preferred embodiment of the invention, the device
comprises a valve body of the intake valve, wherein the valve body
is carried out in a single piece with the main body.
[0047] The device preferably comprises conveying means arranged
downstream of the separation means in order to convey the separated
gas of the mixture to an oil separator filter.
[0048] According to a preferred embodiment of the invention, the
conveying means comprise a gas ejection channel, wherein the
ejection channel is at least partially made in the main body.
[0049] Advantageously, the device comprises a liquid recovery
channel suited to convey the liquid recovered by the oil separator
filter to the compression chamber.
[0050] Preferably, the liquid recovery channel is at least
partially made in the main body.
[0051] More preferably, the device comprises a viewing element for
the inspection of the liquid recovery channel.
[0052] In a preferred embodiment of the invention, the compression
means comprise two helical screws meshing with each other.
[0053] The helical screws are advantageously arranged along
respective longitudinal rotation axes that are substantially
parallel to each other.
[0054] In a preferred embodiment of the invention, the hydraulic
connection channel comprises at least one section aligned along a
corresponding axis that intersects one of the rotation axes of the
helical springs.
[0055] Advantageously, the device comprises canalization means
suited to convey the liquid used to lubricate the moving parts of
the device.
[0056] In a preferred embodiment of the invention the liquid
conveying means convey the liquid to the sliding bearings of the
helical screws.
[0057] The canalization means preferably comprise one or more
channels made inside the main body.
[0058] The liquid is preferably constituted by oil.
[0059] The gas is preferably constituted by air.
BRIEF DESCRIPTION OF THE DRAWINGS
[0060] Further advantages, objects and characteristics, as well as
further embodiments of the present invention are defined in the
claims and will be illustrated in the following description, with
reference to the enclosed drawings; in the drawings, corresponding
or equivalent characteristics and/or components of the present
invention are identified by the same reference numbers. In
particular:
[0061] FIG. 1 shows a schematic view of the operating principle of
a compressor according to a first embodiment of the invention;
[0062] FIG. 2 shows a side view of a compressor according to a
first embodiment of the invention;
[0063] FIG. 3 shows a plan view of the compressor shown in FIG. 2
in which some elements have been removed;
[0064] FIG. 4 shows an axonometric view of some parts of the
compressor shown in FIG. 2;
[0065] FIG. 5 shows FIG. 4 from a different point of view;
[0066] FIG. 6 shows a partially exploded side view of FIG. 2 in
which some elements have been removed;
[0067] FIG. 7 shows an enlarged detail of FIG. 4;
[0068] FIG. 8 shows a sectional view of FIG. 2 along line VIII-VIII
in which some elements have been removed;
[0069] FIG. 9 shows a sectional view of FIG. 3 along line
IX-IX;
[0070] FIG. 10 shows an axonometric view from below of the detail
shown in FIG. 7;
[0071] FIG. 11 shows a plan view from below of the detail shown in
FIG. 7;
[0072] FIG. 12 shows a sectional view of FIG. 3 along line
XII-XII;
[0073] FIG. 13 shows a variant embodiment of the compressor shown
in FIG. 4;
[0074] FIG. 14 shows an enlarged detail of FIG. 13;
[0075] FIG. 15 shows another variant embodiment of the compressor
shown in FIG. 4;
[0076] FIG. 16 shows an enlarged detail of FIG. 15;
[0077] FIG. 17 shows a further variant embodiment of the compressor
shown in FIG. 4;
[0078] FIG. 18 shows an enlarged detail of FIG. 17.
DETAILED DESCRIPTION OF THE PRESENT INVENTION
[0079] Although the present invention is described below with
reference to its embodiments illustrated in the drawings, the
present invention is not limited to the embodiments described below
and illustrated in the drawings. On the contrary, the embodiments
described below and illustrated in the drawings clarify some
aspects of the present invention, the scope of which is defined in
the claims.
[0080] The present invention can be applied in particular to the
production of volumetric compressors used in various sectors, for
example in the mining sector, in building construction or in the
industrial sector. In particular, the present invention can be
especially but not exclusively applied for the production of an
oil-injected volumetric screw compressor powered by means of an
electric motor. It should however be noted that the present
invention is not limited to such application. On the contrary, the
present invention can be conveniently applied in all the cases
requiring the use of a volumetric screw compressor, for example an
engine-driven or motor-driven compressor (internal compression
engine/motor).
[0081] Here below is the description of some embodiments of the
compressor according to the present invention; in the figures,
similar or equivalent characteristics and/or component parts are
identified by the same reference numbers.
[0082] FIG. 1 schematically shows the operating principle of a
preferred embodiment of the oil-injected screw compressor 1
according to the present invention, hereinafter simply referred to
as the "compressor".
[0083] The compressor 1 substantially carries out a compression
treatment on an incoming gas flow Fi, typically air, with a
compression liquid, typically oil, in order to obtain an outgoing
flow of compressed gas Fu.
[0084] The oil-injected screw compressor 1 is a type of machinery
of the volumetric rotary type. It is constituted by a compression
chamber 2 containing two helical rotors, a male (generally driving)
rotor and a female (generally driven) rotor that mesh with each
other, as is explained in greater detail below. The compression of
the gas-oil mixture takes place in the volume included between the
toothing of the two rotors and the body that defines the
compression chamber 2; during rotation, the contact section
included between the profile of the male rotor and the profile of
the female rotor shifts starting from an intake side towards a
delivery side, so that the quantity of air contained therein is
compressed due to the reduction in the available volume.
[0085] The compressor 1 comprises an air intake valve 3, provided
with an apposite intake filter 4, suited to convey the air into the
compression chamber 2. The compressor 1 comprises an oil supply
inlet 5 suited to convey the oil into the compression chamber
2.
[0086] Moving means 6 allow the driving rotor to rotate inside the
compression chamber 2. The compressor 1 also comprises a separation
sector 7 arranged downstream of the compression chamber 2, in which
the compressed oil-air mixture is subjected to a separation
treatment in order to provide, at the outlet, compressed air 8 on
one side and oil 9 on the other side.
[0087] The separated oil 9 is recovered in order to be
re-introduced in the compression chamber 2 through said supply
inlet 5. The re-introduction of said oil 9 into the compression
chamber 2 is conditional on its previous passage in a thermostatic
valve 10 that allows the oil 9 to flow through it towards the
supply inlet 5 only if its temperature is below a pre-determined
limit temperature. In fact, the oil inside the compression chamber
2 is subjected to a temperature increase. The thermostatic valve,
therefore, allows only oil at the correct temperature to flow
through it, while the oil at higher temperature is conveyed to an
oil cooler 11 that lowers its temperature before it is
re-introduced in the recirculation circuit.
[0088] Upstream of the oil supply inlet 5 there is preferably a
filter 12 suited to purify the oil from any impurities.
[0089] The separated compressed air 8 is first conveyed to an oil
separator filter 13 that separates any oil residues present in the
compressed air.
[0090] The recovered residual oil is re-introduced in the
compression chamber 2. Along the re-introduction circuit provided
for the recovered oil there is preferably an oil recovery viewing
element 14 that allows the oil to be monitored.
[0091] The purified compressed air flowing out of the oil separator
filter 13 passes through a minimum pressure valve 15. Said valve 15
allows the passage of air through it only when the pre-determined
rated pressure has been reached.
[0092] The air flowing out of the minimum pressure valve is
preferably directed towards a cooler 16 where it is cooled down.
The cooled air is then conveyed to a usage tank 17, or
alternatively directly to the user.
[0093] Part of the purified compressed air flowing out of the oil
separator filter 13 is conveyed to the intake valve 3 through an
apposite channel 58. The air conveyed through said channel 58
represents the feedback signal that signals to the intake valve 3
when the air passage must be closed or opened. In particular, if
the air pressure in said channel 58 is lower than the
pre-determined rated pressure of the compressor 1, the intake valve
3 is opened. If, on the contrary, the air pressure in said channel
58 is higher than or equal to the pre-determined rated pressure of
the compressor, the intake valve 3 is closed.
[0094] Further elements, not specifically indicated, are preferably
provided in the compressor 1, like for example valves for
discharging oil from the separation sector 7, or safety valves, or
valves for discharging the condensation present in the air tank 17
etc.
[0095] The compressor 1 is described here below with reference to
Figures from 2 to 12, indicating the various parts mentioned
above.
[0096] In the compressor 1 it is first of all possible to identify
a main body 30, shown in particular in FIG. 7, inside which the
compression chamber 2 is defined.
[0097] The main body 30 is preferably produced by means of a
permanent mold casting process, preferably through a metallic
material casting process. The metallic material preferably
comprises aluminium. In variant embodiments of the invention, the
main body 30 can advantageously be obtained by sand casting of a
cast iron alloy.
[0098] On the underside of the main body 30 there is a tank 40
suited to collect the air 8 and the oil 9 generated downstream of
the separation means 7.
[0099] The oil tank 40 is preferably suited to be connected to the
main body 30 by means of screws, as shown in FIG. 6, in such a way
as to obtain a removable structure.
[0100] The tank is advantageously provided with an oil discharge
valve 80.
[0101] In the compression chamber 2 there are, arranged
longitudinally along a main axis X, a first rotor 21 with helical
toothing, or male rotor, and a second rotor 22 with helical
toothing, or female rotor, which meshes with the first rotor 21.
The two rotors 21 and 22 are arranged substantially parallel to
each other and rotate along corresponding rotation axes
substantially parallel to the main axis X of the compression
chamber 2.
[0102] In the embodiment illustrated herein, the first rotor 21 is
the driving rotor and is suited to be connected at one end 24 to
the power means 6. The second rotor 22 is the driven rotor and is
set rotating by the first rotor 21.
[0103] The power means 6 preferably comprise an electric motor
directly connected to the end 24 of the first rotor 21.
[0104] In variant embodiments of the invention the power means may
be of a different type, like for example a combustion engine, or
they may be provided with an indirect, remote connection to a
motor, for example through the interposition of a driving belt or
gears.
[0105] The first rotor 21 preferably comprises four lobes suited to
be engaged in seats provided in the second rotor 22. Said seats are
five in the embodiment illustrated herein.
[0106] In variant embodiments of the invention, however, the number
of lobes and/or seats of the two rotors 21, 22 may be
different.
[0107] The top of the main body 30 is associated with the air
intake valve 3 with the respective filter 4.
[0108] The air intake valve 3 comprises a valve body 31 that houses
internal valve means, fixed to the valve body through suitable
connection means, for example through screws.
[0109] The valve body 31 is preferably carried out in a single
piece with the main body 30.
[0110] The air intake valve 3 communicates with the compression
chamber 2 through an apposite air intake channel 32. Said air
intake channel 32 is preferably provided in the main body 30, as
shown in FIG. 9.
[0111] Regarding the oil supply to the compression chamber 2, this
is achieved through a recirculation circuit that draws the oil from
the bottom of the tank 40 in order to re-introduce it in the
compression chamber 2.
[0112] The oil present on the bottom of the tank 40 is drawn, due
to the effect of pressure inside the tank 40, through a suction
pipe 41, visible in FIG. 6, and then conveyed to the thermostatic
valve 10.
[0113] If the oil temperature is correct, meaning below a limit
temperature, the thermostatic valve 10 directs the oil flow
directly to the oil filter 12 and from there to the compression
chamber 2. If the oil temperature exceeds the limit temperature,
the thermostatic valve 10, instead, directs the oil flow towards a
cooler, not illustrated herein, through a duct connected to an
apposite outlet 42.
[0114] The oil cooled by the cooler is re-introduced upstream of
the thermostatic valve 10 through a duct connected to an apposite
inlet 43.
[0115] The body 46 of the thermostatic valve 10 is preferably
carried out in a single piece with the main body 30.
[0116] Also the supporting seat 55 of the oil filter 12 is
preferably carried out in a single piece with the main body 30.
[0117] The oil flowing out of the oil filter 12 is conveyed to the
compression chamber 2 through an oil injection channel 47, shown in
FIG. 8.
[0118] The oil injection channel 47 is advantageously defined
inside the main body 30.
[0119] As is known, in oil-injected screw compressors the oil
performs also a lubricating function with regard to some parts of
the compressor. In particular, the sliding elements, or bearings,
that support the rotors 21, 22 need lubricating. For this purpose,
the oil in the system is also properly channeled in such a way as
to reach those parts. One of said lubrication channels 49, shown in
FIG. 9, allows a minimum quantity of oil taken from the oil
injection channel 47 to be conveyed to one end of the compression
chamber, in the area where there are the bearings of the rotors 21,
22. Advantageously, said lubrication channel 49 is defined inside
the main body 30.
[0120] The oil-air mixture is thrust from the compression chamber 2
towards an outlet opening 50 by the combined action of the two
rotors 21 and 22, as shown in FIG. 9. The mixture is channeled from
said outlet opening 50 towards the separation means 7.
[0121] According to the present invention, the canalization of the
mixture takes place through a hydraulic connection channel 51. The
hydraulic connection channel 51 is advantageously made in the main
body 30.
[0122] The hydraulic connection channel 51 is substantially aligned
along an inclined axis Y. Said axis Y of the hydraulic connection
channel 51 intersects the main axis X of the compression chamber 2,
as visible in FIG. 9, and thus intersects also the respective
rotation axes of the first and second rotor 21 and 22.
[0123] The separation means 7, as illustrated in FIGS. 9, 10 and
11, are arranged under the compression chamber 2 and are preferably
confined in a hollow portion 33 of the main body 30. In particular,
the hollow portion 33 is defined by a side perimeter wall 34 of the
main body 30. The side perimeter wall 34 is advantageously made in
a single piece with the main body 30.
[0124] In this way the hydraulic connection channel 51 is
advantageously carried out completely in the main body 30.
[0125] In particular, the separation means 7 comprise an injection
element 52 suited to receive the pressurized mixture from the
hydraulic connection channel 51 and to convey said mixture against
the internal surface of the side perimeter wall 34.
[0126] The oil particles are separated from the compressed air due
to a mechanical effect. The flow of the mixture is directed towards
a given route, indicatively shown by the arrow D1 in FIG. 11. The
special geometric configuration of the side wall 34 makes it
possible to reduce the flow speed and thus to separate the oil
particles from the air.
[0127] Following this separation, the oil falls downwards due to
gravity and it is collected in the tank 40.
[0128] The compressed air separated from the oil, instead, remains
in the upper portion 40a of the tank 40.
[0129] Advantageously, according to the present invention the
separation means 7 are partially defined by the lower portion of
the main body 30 and positioned in proximity to the compression
chamber 2.
[0130] This makes it possible to reduce to a minimum the length of
the hydraulic connection chamber 51 between the compression chamber
2 and the separation means 7, more particularly between the outlet
opening 50 and the injection element 52.
[0131] This advantageously makes it possible to reduce the pressure
drops in the mixture to a minimum.
[0132] In other embodiments of the invention, the injection element
may come in different shapes, and it may also be made in a single
piece with the main body 30.
[0133] As already explained, the separated compressed air 8 is in
the upper portion 40a of the tank 40. The compressed air is drawn
from said area 40a through an ejection channel 60 in order to be
conveyed to the oil separator filter 13. Said filter 13 allows the
purification of the compressed air through the elimination of
residual oil particles left therein after the separation step.
[0134] The first portion 60a of the air ejection channel 60 is
advantageously carried out inside the main body 30.
[0135] The oil separator filter 13 comprises a first outlet 61 for
the purified compressed air and a second outlet 62 for the oil
recovered after filtering, as can be seen in FIG. 12.
[0136] The recovered oil is re-introduced in the compression
chamber 2 through a suitable oil recovery channel 62.
[0137] Advantageously, the oil recovery channel 62 is partially
carried out inside the main body 30.
[0138] The oil recovery viewing element 14 is advantageously
positioned along the oil recovery channel 62. Said viewing element
14 makes it possible to monitor the presence of oil inside the oil
recovery channel 62 and thus inside the compressor 1.
[0139] The purified air flowing out of the oil separator filter 13
passes through the minimum pressure valve 15.
[0140] The outgoing flow of compressed air Fu is available at the
outlet of the minimum pressure valve 15.
[0141] The outgoing flow of compressed air Fu can be preferably
stored in a suitable air tank for future use.
[0142] According to the present invention, the presence of a main
body 30 provided with channels for the flow of oil and/or air
and/or the air-oil mixture makes it possible to reduce to a minimum
the length of the routes covered by said fluids and thus to reduce
the pressure drops in the corresponding flows.
[0143] This increases the overall efficiency of the compressor 1
and reduces its dimensions. This results in a compact structure of
the compressor.
[0144] Furthermore, such a type of canalization makes it possible
to avoid the use of ducts to create the channels for the passage of
the fluids, reducing to a minimum the moving parts of the
compressor and also minimizing the risk of breakage and/or
damage.
[0145] This makes the compressor more reliable and reduces the time
and costs required for the maintenance and/or production of the
compressor.
[0146] Furthermore, said techniques for making the main body allow
the compressor's production time and costs to be reduced.
[0147] A further advantage obtained through the present invention
derives from the integration of several parts of the compressor in
the main body 30. In particular, elements like the side perimeter
wall 34 of the separation means 7, the valve body 31 of the air
intake valve 3, the body 46 of the thermostatic valve 10, the
supporting seat 55 of the oil filter 12 are advantageously carried
out in a single piece with the main body 30.
[0148] This results in the compact structure of the compressor, its
reduced size, its reduced overall weight and greater reliability
due to the integration of said elements.
[0149] Said advantages with respect to the known art are at least
partially obtained even if not all of the said elements are
integrated in the main body, but only one or more of the same, as
is explained below with reference to other embodiments of the
invention.
[0150] As explained above, the tank 40 can be associated with the
main body 30 of the compressor 1 through screws. Furthermore, the
separation means 7 are substantially confined in the overall volume
of the main body 30. Said characteristics make the tank 40 easy to
replace to equip the compressor with a tank having a different
shape and/or volume.
[0151] This makes it possible to customize the compressor based on
the different characteristics required from time to time, which may
vary according to the compressor power required or simply in order
to adapt the external shape of the tank in case special sizes are
needed or to satisfy specific aesthetic requirements.
[0152] Again, the tank may be configured so that it can be placed
in a remote position with respect to the main body 30, and in this
case a collection element may be provided that can be applied to
the underside of the main body 30 downstream of the separation
means 7, for example a funnel-shaped element that collects the
separated oil and conveys it to the remote tank. A suitable suction
unit will then be provided to bring the oil from the remote tank
back to the compression chamber 2 so as to allow recirculation.
[0153] FIGS. 13 and 14 show a variant embodiment of the
invention.
[0154] Said embodiment differs from the one previously described
with reference to Figures from 2 to 12 in that the valve body 131
of the intake valve 3 constitutes a separate element that can be
applied to the main body 130. The other elements, that is, the side
perimeter wall 34 of the separation means 7, the valve body 46 of
the thermostatic valve 10 and the supporting seat 55 of the oil
filter 12 are advantageously carried out in a single piece with the
main body 130.
[0155] FIGS. 15 and 16 show another variant embodiment of the
invention.
[0156] Said embodiment differs from the one previously described
with reference to FIGS. 13 and 14 in that the supporting seat of
the oil filter 12, not illustrated herein, constitutes a separate
element with respect to the main body 230. In a preferred
embodiment of the invention, the supporting seat of the oil filter
12 can be applied directly to the main body 230 in an apposite
channel 231. In other embodiments of the invention the supporting
seat of the oil filter 12 is suited to be connected to the main
body 230 through a duct connected to the same channel 231. The
other elements, that is, the side perimeter wall 34 of the
separation means 7 and the body 46 of the thermostatic valve 10,
are advantageously carried out in a single piece with the main body
230.
[0157] FIGS. 17 and 18 show a further variant embodiment of the
invention.
[0158] Said embodiment differs from the one previously described
with reference to FIGS. 15 and 16 in that the body of the
thermostatic valve, not illustrated herein, constitutes a separate
element that can be applied to the main body 330. The side
perimeter wall 34 of the separation means 7 is advantageously made
in a single piece with the main body 330.
[0159] The above clearly shows, therefore, that the compressor that
is the subject of the invention achieves all the set objects, and
in particular achieves the object to provide a volumetric screw
compressor having reduced size and weight compared to the
compressors of the known type, though ensuring higher reliability
and efficiency.
[0160] While the present invention has been described with
reference to the particular embodiments shown in the figures, it
should be noted that the present invention is not limited to the
specific embodiments illustrated and described herein; on the
contrary, further variants of the embodiments described herein fall
within the scope of the present invention, which is defined in the
claims.
* * * * *