NZ627478B2 - Screw compressor - Google Patents
Screw compressor Download PDFInfo
- Publication number
- NZ627478B2 NZ627478B2 NZ627478A NZ62747812A NZ627478B2 NZ 627478 B2 NZ627478 B2 NZ 627478B2 NZ 627478 A NZ627478 A NZ 627478A NZ 62747812 A NZ62747812 A NZ 62747812A NZ 627478 B2 NZ627478 B2 NZ 627478B2
- Authority
- NZ
- New Zealand
- Prior art keywords
- compressor
- motor
- housing
- screw compressor
- screw
- Prior art date
Links
- 238000007906 compression Methods 0.000 claims abstract description 71
- 239000012530 fluid Substances 0.000 claims abstract description 57
- 238000001816 cooling Methods 0.000 claims abstract description 46
- 238000005461 lubrication Methods 0.000 claims abstract description 24
- 230000001050 lubricating Effects 0.000 claims abstract description 9
- 210000003128 Head Anatomy 0.000 claims description 17
- 230000000694 effects Effects 0.000 claims description 5
- 230000005484 gravity Effects 0.000 claims description 5
- 230000036316 preload Effects 0.000 claims description 4
- 210000003027 Ear, Inner Anatomy 0.000 claims description 2
- 230000001360 synchronised Effects 0.000 claims description 2
- 230000001419 dependent Effects 0.000 claims 1
- 239000002826 coolant Substances 0.000 description 8
- 239000000314 lubricant Substances 0.000 description 7
- 230000001808 coupling Effects 0.000 description 4
- 238000010168 coupling process Methods 0.000 description 4
- 238000005859 coupling reaction Methods 0.000 description 4
- 239000000203 mixture Substances 0.000 description 3
- 238000009434 installation Methods 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
- F04C15/00—Component parts, details or accessories of machines, pumps or pumping installations, not provided for in groups F04C2/00 - F04C14/00
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
- F04C15/00—Component parts, details or accessories of machines, pumps or pumping installations, not provided for in groups F04C2/00 - F04C14/00
- F04C15/06—Arrangements for admission or discharge of the working fluid, e.g. constructional features of the inlet or outlet
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
- F04C18/00—Rotary-piston pumps specially adapted for elastic fluids
- F04C18/02—Rotary-piston pumps specially adapted for elastic fluids of arcuate-engagement type, i.e. with circular translatory movement of co-operating members, each member having the same number of teeth or tooth-equivalents
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
- F04C18/00—Rotary-piston pumps specially adapted for elastic fluids
- F04C18/02—Rotary-piston pumps specially adapted for elastic fluids of arcuate-engagement type, i.e. with circular translatory movement of co-operating members, each member having the same number of teeth or tooth-equivalents
- F04C18/04—Rotary-piston pumps specially adapted for elastic fluids of arcuate-engagement type, i.e. with circular translatory movement of co-operating members, each member having the same number of teeth or tooth-equivalents of internal-axis type
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
- F04C18/00—Rotary-piston pumps specially adapted for elastic fluids
- F04C18/08—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing
- F04C18/12—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type
- F04C18/14—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type with toothed rotary pistons
- F04C18/16—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type with toothed rotary pistons with helical teeth, e.g. chevron-shaped, screw type
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
- F04C18/00—Rotary-piston pumps specially adapted for elastic fluids
- F04C18/08—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing
- F04C18/12—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type
- F04C18/14—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type with toothed rotary pistons
- F04C18/18—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type with toothed rotary pistons with similar tooth forms
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
- F04C2/00—Rotary-piston machines or pumps
- F04C2/08—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing
- F04C2/12—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type
- F04C2/14—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type with toothed rotary pistons
- F04C2/16—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type with toothed rotary pistons with helical teeth, e.g. chevron-shaped, screw type
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
- F04C2240/00—Components
- F04C2240/40—Electric motor
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
- F04C2240/00—Components
- F04C2240/50—Bearings
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
- F04C23/00—Combinations of two or more pumps, each being of rotary-piston or oscillating-piston type, specially adapted for elastic fluids; Pumping installations specially adapted for elastic fluids; Multi-stage pumps specially adapted for elastic fluids
- F04C23/008—Hermetic pumps
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
- F04C23/00—Combinations of two or more pumps, each being of rotary-piston or oscillating-piston type, specially adapted for elastic fluids; Pumping installations specially adapted for elastic fluids; Multi-stage pumps specially adapted for elastic fluids
- F04C23/02—Pumps characterised by combination with or adaptation to specific driving engines or motors
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
- F04C28/00—Control of, monitoring of, or safety arrangements for, pumps or pumping installations specially adapted for elastic fluids
- F04C28/06—Control of, monitoring of, or safety arrangements for, pumps or pumping installations specially adapted for elastic fluids specially adapted for stopping, starting, idling or no-load operation
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
- F04C29/00—Component parts, details or accessories of pumps or pumping installations, not provided for in groups F04C18/00 - F04C28/00
- F04C29/0042—Driving elements, brakes, couplings, transmissions specially adapted for pumps
- F04C29/0085—Prime movers
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
- F04C29/00—Component parts, details or accessories of pumps or pumping installations, not provided for in groups F04C18/00 - F04C28/00
- F04C29/04—Heating; Cooling; Heat insulation
- F04C29/045—Heating; Cooling; Heat insulation of the electric motor in hermetic pumps
Abstract
Screw compressor (1) with a compression chamber (2) that is formed by a compression housing (3), in which a pair of meshed helical compressor rotors (4, 5) in the form of a screw are rotatably mounted and with a drive motor (14) that is provided with a motor chamber (16) formed by a motor housing (15), in which a motor shaft (17) is rotatably mounted, and this motor shaft drives at least one of the two compressor rotors, whereby the compression housing and the motor housing are connected directly together to form a compressor housing (28), whereby the motor chamber and the compression chamber are not sealed off from one another and whereby the rotor shafts (7, 8) of the compressor rotors, as well as the motor shaft, extend along axial directions (??', BB', CC ) that are oblique or transverse to the horizontal plane. The compression housing forms a base or bottom section of the compressor housing, and the motor housing forms a head or top section of the compressor housing. The compressor rotors are supported in the compressor housing by means of one or more bearings (32, 33) and the motor shaft is supported in the compressor housing by means of one or more motor bearings (35). The screw compressor is provided with a fluid (37), with which both the drive motor and the compressor rotors are cooled and/or lubricated. The screw compressor is provided with a cooling circuit (38) for cooling both the drive motor and the screw compressor and through which fluid can flow from the head of the compressor housing to the bases of the compressor housing. The screw compressor is provided with a lubrication circuit (40, 45) for lubricating the motor bearing or the motor bearings as well as the inlet bearings. The cooling circuit and the lubrication circuit are connected to a return circuit (65) for the removal of fluid from the outlet in the base of the screw compressor and for returning the removed fluid to the head of the compressor housing. 5), in which a motor shaft (17) is rotatably mounted, and this motor shaft drives at least one of the two compressor rotors, whereby the compression housing and the motor housing are connected directly together to form a compressor housing (28), whereby the motor chamber and the compression chamber are not sealed off from one another and whereby the rotor shafts (7, 8) of the compressor rotors, as well as the motor shaft, extend along axial directions (??', BB', CC ) that are oblique or transverse to the horizontal plane. The compression housing forms a base or bottom section of the compressor housing, and the motor housing forms a head or top section of the compressor housing. The compressor rotors are supported in the compressor housing by means of one or more bearings (32, 33) and the motor shaft is supported in the compressor housing by means of one or more motor bearings (35). The screw compressor is provided with a fluid (37), with which both the drive motor and the compressor rotors are cooled and/or lubricated. The screw compressor is provided with a cooling circuit (38) for cooling both the drive motor and the screw compressor and through which fluid can flow from the head of the compressor housing to the bases of the compressor housing. The screw compressor is provided with a lubrication circuit (40, 45) for lubricating the motor bearing or the motor bearings as well as the inlet bearings. The cooling circuit and the lubrication circuit are connected to a return circuit (65) for the removal of fluid from the outlet in the base of the screw compressor and for returning the removed fluid to the head of the compressor housing.
Description
Screw compressor.
__________________
The present invention relates to a screw compressor.
More specifically the present invention relates to a screw
compressor that at least comprises a compression chamber
that is formed by a compression housing, in which a pair of
meshed helical compressor rotors are rotatably mounted,
which have rotor shafts that extend along a first and
second axial direction that are parallel to one another,
whereby the screw compressor also contains a least a drive
motor, and which is provided with a motor chamber formed by
a motor housing in which a motor shaft is rotatably
mounted, and this motor shaft extends along a third axial
direction and which drives at least one of the
aforementioned two helical compressor rotors.
Such screw compressors are already known, which however
present a number of disadvantages or which are open to
improvement.
In order to be able to drive the compressor rotors, in the
known screw compressors generally the motor shaft of the
drive motor is directly or indirectly, for example via a
drive belt or a gearwheel transmission, coupled to the
rotor shaft of one of the compressor rotors.
Hereby the rotor shaft of the compressor concerned must be
adequately sealed, which is far from easy.
Indeed, a certain pressure supplied by the screw compressor
prevails in the compression housing, which has to be
screened off from the compressor sections that are not
under this pressure or from the ambient pressure.
For such applications, a “contact seal” is often used.
The rotor shaft of the compressor rotor concerned however
turns at very high speeds, such that such a type of seal
brings about enormous power losses during the operation of
the screw compressor, resulting in a reduced efficiency of
the screw compressor.
Moreover, such a “contact seal” is subject to wear, and if
it is not carefully installed such a “contact seal” is very
sensitive to the occurrence of leaks.
Another aspect of the known screw compressors of the type
described above that is open to improvement, is that both
the drive motor and the screw compressor have to be
provided with lubrication and cooling, that generally
consist of separate systems and thus are not attuned to one
another, require a number of different types of lubricants
and/or coolants, and are thereby complicated or expensive.
In addition, in such known screw compressors with separate
cooling systems for the drive motor and compressor rotors,
the possibilities for recovering the lost heat stored in
the coolants in an optimum way are not fully utilised.
The purpose of the invention is thus to provide a solution
to one or more of the foregoing disadvantages and any other
disadvantages.
More particularly, it is an objective of the invention to
offer a screw compressor that is robust and simple, whereby
the risk of wear and leaks are kept to a minimum, whereby
the lubrication of bearings and the cooling of components
is realised by very simple means and whereby improved
recovery of the heat losses occurring can be achieved.
In accordance with an aspect of the present invention,
there is provided a screw compressor that at least
comprises the following elements: a compression chamber
that is formed by a compression housing in which a pair of
meshed helical compressor rotors in the form of a screw are
rotatably mounted, which have rotor shafts that extend
along a first axial direction and a second axial direction
that are parallel to one another; a drive motor that is
provided with a motor chamber formed by a motor housing, in
which a motor shaft is rotatably mounted that extends along
a third axial direction and that drives at least one of the
aforementioned two compressor rotors, wherein the
compression housing and the motor housing are connected
directly to one another to form a compressor housing,
whereby the motor chamber and the compression chamber are
not sealed off from one another and whereby the screw
compressor is a vertical screw compressor whereby the rotor
shafts of the compressor rotors as well as the motor shaft
This advantage and other stated advantages are advantages of at least preferred embodiments of the
invention. It is not necessary for every embodiment of the invention to meet each stated advantage.
extend along axial directions that are at an angle with or
transverse to the horizontal plane during normal operation
of the screw compressor, whereby the compression housing
forms a base or bottom section of the compressor housing,
and whereby the motor housing forms a head or top section
of the compressor housing, wherein the compressor rotors
are supported in the compressor housing by means of one or
more bearings and the motor shaft is supported in the
compressor housing by means of one or more motor bearings,
and wherein the screw compressor is provided with a fluid,
with which both the drive motor and the compressor rotors
are cooled and/or lubricated, whereby the screw compressor
is provided with a cooling circuit for cooling both the
drive motor and the screw compressor and through which
fluid can flow from the head of the compressor housing to
the bases of the compressor housing, whereby the screw
compressor is provided with a lubrication circuit for
lubricating the motor bearing or the motor bearings as well
as the inlet bearings and whereby the cooling circuit and
the lubrication circuit are connected to a return circuit
for the removal of fluid from the outlet in the base of the
screw compressor and for returning the removed fluid to the
head of the compressor.
The term “comprising” as used in this specification and
claims means “consisting at least in part of”. When
interpreting statements in this specification and claims
which include the term “comprising”, other features besides
the features prefaced by this term in each statement can
also be present. Related terms such as “comprise” and
“comprised” are to be interpreted in a similar manner.
A first big advantage of such a screw compressor according
to the invention is that the compressor housing forms a
whole, consisting of a compression housing and motor
housing that are directly attached to one another, so that
the drive means of the compressor rotors, in the form of a
drive motor, are integrated directly in the screw
compressor.
It should be noted here that the compression chamber and
the motor chamber do not have to be sealed off from one
another, as due to the direct installation of the motor
housing and compression housing together, the motor shaft
and one of the compressor rotors can be coupled completely
within the contours of the compressor housing, without
having to pass through a section that is at a different
pressure, such as is usual in the known screw compressors,
for example, whereby the motor shaft is coupled to a
compressor rotor, whereby a section of the coupling is
exposed to the ambient pressure.
The characteristic that such a seal between the compression
chamber and the motor chamber is not necessary, constitutes
a considerable advantage of a screw compressor according to
the invention, as a higher energy efficiency of the screw
compressor is obtained than with the known screw
compressors, and no wear of such a seal is possible and
leaks as a result of the poor installation of such a seal
are avoided.
Another advantage of such a screw compressor according to
the invention, whereby the motor chamber and the
compression chamber form a closed whole, is that no
external air cooling is required, so that the screw
compressor can be better insulated with respect to the
environment on a thermal level, and certainly also on an
acoustic level, such that the noise generated by the screw
compressor can be greatly reduced compared to the existing
screw compressors.
Through better thermal insulation of the screw compressor,
sensitive electronic components installed in the vicinity
of the screw compressor are more easily or better shielded
against the heat produced by the screw compressor.
Another very important aspect of a screw compressor
according to the invention is that the same lubricants and
coolants can be used in a very simple way for both the
drive motor and the compressor rotors, as the motor chamber
and the compression chamber are not separated from one
another by a seal.
According to a screw compressor according to the invention,
the screw compressor is provided with a fluid, for example
an oil, with which both the drive motor and the compressor
rotors are cooled and/or lubricated.
Thus the design of the screw compressor according to the
invention is greatly simplified, fewer different coolants
and/or different lubricants are needed, and the whole can
thus be constructed more cheaply.
Moreover, it is the case that by having a fluid circulate
during a single cycle both along the drive motor and along
the compressor elements to cool the screw compressor, this
fluid undergoes a greater temperature change than when
separate cooling systems are used for the drive motor and
the compressor rotors.
Indeed, this fluid will absorb heat from both the drive
motor and the compressor elements instead of just heat from
one of the two components.
A consequence of this is that the heat stored in the fluid
can be more easily recovered than when the fluid only
undergoes a small temperature change.
However, account must be taken of the fact that a different
operating temperature will have to be chosen for the drive
motor or the compressor rotors.
Another advantage of a screw compressor according to the
invention is due to its characteristic that the rotor
shafts of the compressor rotors, as well as the motor
shaft, in normal operation of the screw compressor extend
along axial directions that are oblique or transverse to
the horizontal plane.
Indeed, such an oblique position of the shafts with respect
to the horizontal plane stimulates a good flow of the
lubricants and/or coolants, as in principle they can flow
over the drive motor and the compressor rotors under the
influence of gravity, without additional means or
additional energy being required for this purpose.
According to a preferred embodiment of the screw compressor
according to the invention, the rotor shafts of the
compressor rotors, as well as the motor shaft, in normal
operation of the screw compressor extend along axial
directions that are vertical.
As a result the effect of gravity can of course be
reinforced, as a least insofar the channels for lubricants
and coolants also extend vertically.
With the intention of better showing the characteristics of
the invention, a preferred embodiment of a screw compressor
according to the invention is described hereinafter by way
of an example, without any limiting nature, with reference
to the accompanying drawings, wherein:
figure 1 schematically shows a screw compressor
according to the invention; and,
figure 2 schematically shows an assembly to illustrate
the use of such a screw compressor according to the
invention.
The screw compressor 1 according to the invention shown in
figure 1 first and foremost contains a compression chamber
2 that is formed by a compression housing 3.
In the compression chamber 2 a pair of meshed helical
compressor rotors are rotatably mounted, more specifically
a first helical compressor rotor 4 and a second helical
compressor rotor 5.
These helical compressor rotors 4 and 5 have a helical
profile 6 that is affixed around a rotor shaft of the
compressor rotor 4 and 5 concerned, respectively rotor
shaft 7 and rotor shaft 8.
Hereby the rotor shaft 7 extends along a first axial
direction AA’, while the rotor shaft 8 extends along a
second axial direction BB’.
Moreover, the first axial direction AA’ and the second
axial direction BB’ are parallel to one another.
Moreover, there is an inlet 9 through the walls of the
compression housing 3 up to the compression chamber 2 for
drawing in air, for example air from the surrounds 10 or
originating from a previous compressor stage, as well as an
outlet 11 for the removal of compressed air, for example to
a compressed air consumer or a subsequent compressor stage.
The compression chamber 2 of the screw compressor 1 is, as
is known, formed by the inside walls of the compression
housing 3, which have a form that closely fit the external
contours of the pair of helical compressor rotors 4 and 5
in order to drive the air drawn in via the inlet 9, during
the rotation of the compressor rotors 4 and 5, between the
helical profile 6 and the inside walls of the compression
housing 3 in the direction of the outlet 11, and thus to
compress the air, and to build up pressure in the
compression chamber 2.
The direction of rotation of the compressor rotors 4 and 5
determines the drive direction and thus also determines
which of the passages 9 and 11 will act as the inlet 9 or
the outlet 11.
The inlet 9 is hereby at the low pressure end 12 of the
compressor rotors 4 and 5, while the outlet 11 is near the
high pressure end 13 of the compressor rotors 4 and 5.
Moreover, the screw compressor is provided with a drive
motor 14.
This drive motor 14 is provided with a motor housing 15
that is affixed above the compression housing 3 and whose
inside walls enclose a motor chamber 16.
In the motor chamber 16, a motor shaft 17 of the drive
motor 14 is rotatably mounted, and in the embodiment shown
this motor shaft 17 is directly coupled to the first
helical compressor rotor 4 in order to drive it, but this
does not necessarily need to be the case.
The motor shaft 17 extends along a third axial direction
CC’, which in this case also coincides with the axial
direction AA’ of the rotor shaft 7, so that the motor shaft
17 is in line with the compressor rotor 4 concerned.
To couple the motor shaft 17 to the compressor rotor 4, one
end 18 of the motor shaft 17 is provided with a cylindrical
recess 19 in which the end 20 of the rotor shaft 7, that is
located close to a low pressure end 12 of the compressor
rotor 4, can be suitably inserted.
Moreover, the motor shaft 17 is provided with a passage 21
in which a bolt 22 is affixed, which is screwed into an
internal screw thread provided in the aforementioned end 20
of the rotor shaft 7.
Of course there are many other ways of coupling the motor
shaft 17 to the rotor shaft 7, which are not excluded from
the invention.
Alternatively it is indeed not excluded that a screw
compressor 1 according to the invention is constructed such
that the motor shaft 17 also forms the rotor shaft 7 of one
of the compressor rotors 4, by constructing the motor shaft
17 and rotor shaft 7 as a single piece, such that no
coupling means are needed for coupling the motor shaft 17
and rotor shaft 7.
Moreover, in the example shown in figure 1, the drive motor
14 is an electric motor 14 with a motor rotor 23 and motor
stator 24, whereby more specifically in the example shown
the motor rotor 23 of the electric motor 14 is equipped
with permanent magnets 25 to generate a rotor field, while
the motor stator 24 is equipped with electrical windings 26
to generate a stator field that is switched and acts in a
known way on the rotor field in order to bring about a
rotation of the motor rotor 23, but other types of drive
motors 14 are not excluded according to the invention.
According to a preferred embodiment of a screw compressor 1
according to the invention, the electric motor 14 is a
synchronous motor 14.
It is highly characteristic of the invention that the
compression housing 3 and the motor housing 15 are
connected directly together, in this case by bolts 27, to
form a compressor housing 28 of the screw compressor 1,
whereby more specifically the motor chamber 16 and the
compression chamber 2 are not sealed off from one another.
In the example shown the compression housing 3 and the
motor housing 15 are actually constructed as separate parts
of the compressor housing 28, that more or less correspond
to the parts of the screw compressor 1 that respectively
contain the drive motor 14 and the compressor rotors 4 and
However, attention is drawn here to the fact that the motor
housing 15 and the compression housing 3 do not necessarily
have to be constructed as such separate parts, but just as
well can be constructed as a single whole.
As an alternative it is not excluded that the compressor
housing 28 is constructed from more or fewer parts, that
entirely or partially contain the compressor rotors 4 and 5
or the drive motor 14 or all these components together.
It is essential for the invention that, in contrast to what
is the case with known screw compressors, no seal is used
that separates the motor chamber 16 and the compression
chamber 2 from one another, which for this reason alone, as
explained in the introduction, is a considerable advantage
of a screw compressor 1 according to the invention, on
account of the lower energy losses, less wear and lower
risk of leaks.
In order to be able to control the electric drive motor 14
without problems, without having to use sensors that are
exposed to the high pressures present in the set formed by
the motor chamber 2 and the compressor chamber 16, the
inductance of the electric motor 14 along the direct axis
DD’, whereby the direction DD’ of this direct axis
corresponds to the primary direction DD’ of the rotor
field, is sufficiently different to the inductance of the
electric motor 14 along an axis QQ’ perpendicular to it,
more specifically the quadrature axis QQ’.
Preferably these inductances of the electric motor 14
according to the aforementioned direct axis DD’ and the
quadrature axis QQ’ are different enough such that the
position of the motor rotor 23 in the motor stator 24 can
be determined by measuring the aforementioned inductance
difference in the vicinity outside the compressor housing
According to the invention the drive motor 14 must of
course also be of a type that can withstand the compressor
pressure.
A practical problem that must be solved with such drive
motors 14 is to do with the electrical connections of the
drive motor 14, and more specifically the transit holes for
the electric cables from the outside, where atmospheric
pressures prevail, through the motor housing 15 to the
motor chamber 16, which in a screw compressor 1 according
to the invention is under compressor pressure, which of
course is not a simple problem.
To realise such an electrical connection of the drive motor
14, according to the invention use can be made of a
connection in which a glass-to-metal seal is applied.
Metal pins are embedded in the openings in the motor
housing 15, more specifically by sealing them off in the
openings with a glass substance that is melted in around
the pins.
Then the electric cables concerned can be connected to both
ends of the pins.
Furthermore the drive motor 14 is preferably of a type that
can generate a sufficiently large start-up torque in order
to start the screw compressor 1 when the compression
chamber 2 is under compressor pressure, whereby the release
of compressed air when the screw compressor 1 is stopped
can be avoided.
The fact that the compression chamber 2 and the motor
chamber 16 and the compression chamber 1 form a closed
whole, in combination with another characteristic of a
screw compressor 1 according to the invention, more
specifically that the screw compressor 1 is not a
horizontal, but preferably a vertical screw compressor 1,
yields other important technical advantages, as will be
demonstrated hereinafter.
A vertical screw compressor 1 here means that the rotor
shafts 7 and 8 of the compressor rotors 4 and 5, as well as
the motor shaft 17 of the drive motor 14, during normal
operation of the screw compressor 1 extend along axial
directions AA’, BB’ and CC’ that are vertical.
However, according to the invention it is not excluded that
the perfect vertical position can be departed from, for
example by applying an oblique non-horizontal position.
According to an even more preferred embodiment of a screw
compressor 1 according to the invention, the compression
housing 2 hereby forms a base 29 or bottom part of the
entire compressor housing 28 of the screw compressor 1,
while the motor housing 15 forms a head 30 or top part of
the compressor housing 28.
Furthermore, the low pressure ends 12 of the compressor
rotors 4 and 5 are preferably the ends 12 that are the
closest to the head 30 of the compressor housing 29, and
the high pressure ends 13 of the compressor rotors 4 and 5
are the ends 13 that are the closest to the base 29 of the
compressor housing 28, so that the inlet 12 for drawing in
air and the low pressure side of the screw compressor 1 are
higher than the outlet 13 for removing compressed air.
This configuration is particularly useful to obtain
efficient cooling and lubrication of the drive motor 14 and
compressor rotors 4 and 5, and also to maintain operational
reliability without additional means, when the screw
compressor 1 is stopped, more specifically because the
coolant and lubricant present can flow out under the effect
of gravity.
The components of the screw compressor 1 that certainly
must be lubricated and cooled are of course the components
that rotate, more specifically the compressor rotors 4 and
, the motor shaft 17, as well as the bearings with which
these components are supported in the compressor housing
28.
A useful bearing arrangement is also shown in figure 1, as
it enables the motor shaft 17 and the rotor shaft 7 and/or
rotor shaft 8 to be constructed with a limited cross-
section, or at least with a smaller cross-section than is
generally the case with the known screw compressors of a
similar type.
In this case the rotor shafts 7 and 8 are hereby supported
at both ends 12 and 13 by a bearing, while the motor shaft
17 is also supported by bearings at its end 31 on the head
side of the compressor housing 28.
More specifically, the compressor rotors 4 and 5 are
supported axially and radially in the compressor housing 28
by bearings at their high pressure end 13, by means of a
number of outlet bearings 32 and 33, in this case
respectively a cylindrical bearing or needle bearing 32 in
combination with a deep groove ball bearing 33.
On the other hand, at their low pressure end 12 the
compressor rotors 4 and 5 are only radially supported in
the compressor housing 28 by bearings, by means of an inlet
bearing 34, which in this case is also a cylindrical
bearing or needle bearing 34.
Finally, at the end 31 opposite the driven compressor rotor
4, the motor shaft 17 is supported axially and radially in
the compressor housing 28 by bearings, by means of a motor
bearing 35, which in this case is a deep groove ball
bearing 35.
Tensioning means 36 are hereby provided at the end 31, in
the form of a spring element 36, and more specifically a
cupped spring washer 36, whereby these tensioning means 36
are intended to exert an axial pre-load on the motor
bearing 35, and this pre-load is oriented along the axial
direction CC’ of the motor shaft 17 in the direction
against the force generated by the meshed helical
compressor rotors 4 and 5, so that the axial bearing at the
high pressure end of the compressor rotors 4 and 5 are
somewhat relieved.
Of course many other bearing arrangements for supporting
the rotor shafts 7 and 8 and the motor shaft 17, realised
with all kinds of different bearings, are not excluded from
the invention.
For cooling and lubricating the screw compressor 1, the
screw compressor 1 according to the invention is preferably
provided with a fluid 37, for example an oil, with which
both the drive motor 14 and the compressor rotors 4 and 5
are cooled or lubricated, and preferably both the cooling
function and the lubricating function are fulfilled by the
same fluid 37.
Furthermore, a screw compressor 1 according to the
invention is equipped with a cooling circuit 38 for cooling
both the drive motor 14 and the screw compressor 1 and
through which fluid 37 can flow from the head 30 of the
compressor housing 28 to the base 29 of the compressor
housing 28.
In the example shown this cooling circuit 38 consists of
cooling channels 39 that are provided in the motor housing
15 and of the compression chamber 2 itself.
The cooling channels 39 ensure that the fluid 37 does not
get into the air gap between the motor rotor 23 and the
motor stator 24, which would give rise to energy losses and
similar.
In the example shown, the majority of the cooling channels
39 are oriented axially and some parts of the cooling
channels 39 are also concentric to the axis AA’, but the
orientation of these cooling channels 39 does not play much
of a role, as long as a good flow of the fluid 37 is
assured.
According to the invention it is the intention here that
the fluid 37 is driven through the cooling channels 39
under a compressor pressure generated by the screw
compressor 1 itself, as will be explained hereinafter on
the basis of figure 2.
Thus a sufficiently large flow of fluid 37 can be obtained
through the cooling channels 39, which is necessary in view
of the considerable heat generated in the screw compressor
On the other hand the screw compressor 1 is also provided
with a lubrication circuit 40 for lubricating the motor
bearing 35 as well as the inlet bearings 34.
This lubrication circuit 40 in this case consists of one or
more branches 41 to the cooling channels 39 in the motor
housing 15 for the supply of fluid 37 to the motor bearing
, and of outlet channels 42 for removing fluid 37 from
the motor bearing 35 up to the inlet bearings 34, from
where the fluid 37 can flow in the compression chamber 2.
In this way the fluid 37 can easily flow from the motor
bearing 35 to the inlet bearings 34, from where the fluid
37 can further freely flow over the compressor rotors 4 and
In the example shown the branches 41 primarily extend in a
radial direction, but again this is not necessarily the
case according to the invention.
Moreover the branches 41 have a diameter that is
substantially smaller than the diameter of the cooling
channels 39, such that only a small amount of fluid flows
through the lubrication circuit 40 compared to the amount
of fluid 37 that flows through the cooling circuit 38 for
the cooling.
It is hereby the intention that the flow of fluid 37 in the
lubrication circuit 40, and certainly in the axially
extending outlet channels 42, primarily takes place under
the effect of gravity, and only to a small extent as a
result of a compressor pressure generated by the screw
compressor 1, so that when the screw compressor 1 is
stopped the fluid 37 can flow out and does not accumulate.
Another advantageous characteristic is that a reservoir 43
is provided under the motor bearing 35 to receive the fluid
37, to which the branches 41 and the outlet channels 42 are
connected.
Moreover, the reservoir 43 is hereby preferably sealed from
the motor shaft 17 by means of a labyrinth seal 44.
Another aspect of a screw compressor 1 according to the
invention is that a lubrication circuit 45 is provided in
the base 29 to lubricate the outlet bearings 32 and 33.
This lubrication circuit 45 consists of one or more supply
channels 46 for the supply of fluid 37 from the compression
chamber 2 to the outlet bearings 32 and 33, as well as one
or more outlet channels 47 for the return of fluid 37 from
the outlet bearings 32 and 33 to the compression chamber 2.
Hereby it is advantageous for the outlet channels 47 to
lead to the compression chamber 2 above the entrance of the
supply channels 46 in order to obtain the necessary
pressure difference for a smooth flow of fluid 37 through
the lubrication circuit 45.
Moreover, according to the invention the motor housing 15
and/or the compressor housing 3, with their cooling
channels 39, branches 41, outlet channels 42, lubrication
circuit 45 and reservoir 43, are preferably produced by
extrusion, as this is a very simple manufacturing process.
Thus it will be understood that a very simple system is
realised for lubricating the various bearings 32 to 35, as
well as for cooling the drive motor 14 and the compressor
rotors 4 and 5.
Figure 2 shows a more practical arrangement in which a
screw compressor 1 according to the invention is applied.
An inlet pipe 48 is hereby connected to the inlet 9 of the
screw compressor 1 in which there is an inlet valve 49,
which enables the inflow of the air supply to the screw
compressor 1 to be controlled.
According to a preferred embodiment of a screw compressor 1
according to the invention, this inlet valve 49 is
preferably a non-controlled or self-regulating valve, and
in an even more preferred embodiment this inlet valve 49 is
a non-return valve 49, which is indeed also the case in the
example of figure 2.
An outlet pipe 50 is connected to the outlet 11 that leads
to a pressure vessel 51 that is equipped with an oil
separator 52.
Compressed air, mixed with fluid 37, more specifically oil
37, that acts as a lubricant and coolant, leaves the screw
compressor 1 through the outlet 11, whereby the mixture in
the pressure vessel 51 is separated into two flows by the
oil separator 52, on the one hand an outflow of compressed
air via the air outlet 53 above the pressure vessel 51, and
on the other hand an outflow of fluid 37 via an oil outlet
54 at the bottom of the pressure vessel 51.
In the example shown, the air outlet 53 of the pressure
vessel 51 is also equipped with a non-return valve 55.
Furthermore a consumer pipe 56, which can be closed by a
tap or valve 57, is connected to the air outlet 53.
A section 58 of the consumer pipe 56 is constructed as a
radiator 58 that is cooled by means of a forced airflow of
surrounding air 10 originating from a fan 59, of course
with the intention of cooling the compressed air.
Analogously, the oil outlet 54 is also provided with an oil
return pipe 60 that is connected to the head 30 of the
compressor housing 28 for the injection of oil 37.
A section 61 of the oil return pipe 60 is also constructed
as a radiator 61, which is cooled by a fan 62.
A bypass pipe 63 is also provided in the oil return pipe 60
that is affixed in parallel over the section of the oil
return pipe 60 with radiator 61.
Via one valve 64, the oil 37 can be sent through the
section 61, in order to cool the oil 37, for example during
the normal operation of the screw compressor 1, or through
the bypass pipe 63 in order not to cool the oil 37, such as
during the start-up of the screw compressor 1, for example.
As shown in greater detail in figure 2, the cooling circuit
38 and the lubrication circuit 40 are in fact connected to
a return circuit 65 for the removal of fluid 37 from the
outlet 11 in the base 29 of the screw compressor 1 and for
returning the removed fluid 37 to the head 30 of the
compressor housing 28.
In the example shown this aforementioned return circuit 65
is formed by the set consisting of the outlet pipe 50
provided at the outlet 11, the pressure vessel 51 connected
to the outlet pipe 50, and the oil return pipe 60 connected
to the pressure vessel 51.
Hereby, the outlet pipe 50 is connected to the base 29 of
the compressor housing 28 and the oil return pipe 60 is
connected to the head 30 of the compressor housing 28.
Moreover, according to the invention it is the intention
that during the operation of the screw compressor 1, the
fluid 37 is driven through the return circuit 65 from the
base 29 to the head 30 of the compressor housing 28 as a
result of a compressor pressure generated by the screw
compressor 1 itself.
This is also indeed the case in the embodiment of figure 2,
as the return circuit 65 starts from the side of the
compression chamber 2 at the base 29 of the compressor
housing 28, and this side of the compression chamber 2 is
located at the high pressure end 13 of the compressor
rotors 4 and 5.
According to a preferred embodiment of a screw compressor 1
according to the invention the outlet pipe 50 between the
pressure vessel 51 and the screw compressor 1 is free of
closing means in order to enable a flow through the outlet
pipe 50 in both directions.
According to an even more preferred embodiment of a screw
compressor 1 according to the invention, additionally the
oil return pipe 60 is also free of self-regulating non-
return valves.
A great advantage of such an embodiment of a screw
compressor 1 according to the invention is that its valve
system for closing the screw compressor 1 is much simpler
than with the known screw compressors.
More specifically only an inlet valve 49 is needed to
obtain a correct operation of the screw compressor 1, as
well as means to close off the air outlet 53, such as for
example a non-return valve 55 or a tap or valve 57.
In addition, the inlet valve 49 does not even need to be a
controlled valve 49 as is usually the case, but on the
contrary preferably a self-regulating non-return valve 49,
as shown in figure 2.
Moreover, a more energy-efficient operation can be achieved
even with this one valve 49.
Indeed, with a screw compressor 1 according to the
invention the drive motor 14 is integrated in the
compressor housing 28, whereby the motor chamber 16 and the
compression chamber 2 are not sealed off from one another,
so that the pressure in the pressure vessel 51 and the
pressure in the compression chamber 2, as well as in the
motor chamber 16 are practically equal, i.e. equal to the
compressor pressure.
Consequently when the screw compressor 1 is stopped, the
oil 37 present in the pressure vessel 51 will not be
inclined to flow back to the screw compressor 1, and more
specifically the drive motor 14, as is indeed the case with
the known screw compressors whereby the pressure in the
drive motor is generally the ambient pressure.
With known screw compressors, a non-return valve always has
to be provided in the oil return pipe 60, which is not the
case with a screw compressor according to the invention.
Analogously, with the known screw compressors a non-return
valve is provided in the outlet pipe 50, in order to
prevent the compressed air in the pressure vessel being
able to escape via the screw compressor and the inlet when
the screw compressor is stopped.
In the known screw compressors these non-return valves also
constitute a significant energy loss.
With a screw compressor 1 according to the invention it is
sufficient to hermitically close off the inlet 9 by means
of the inlet valve 49, when the screw compressor 1 is
stopped, so that both the pressure vessel 51 and the
compression chamber 2 and motor chamber 16 remain under
compression pressure after the screw compressor 1 has
stopped.
The inlet 9 is hermetically closed using a non-return valve
49, automatically under the pressure present in the screw
compressor 1 and by the elasticity in the non-return valve
49, whereby when the screw compressor 1 is stopped there is
no further suction force from the air to pull the non-
return valve 49 open.
This is not possible with known screw compressors, as they
are always provided with a seal that separates the motor
chamber and the compression chamber from one another,
generally realised by means of a seal on the rotating rotor
shaft 7.
Keeping the compression chamber under pressure with the
known screw compressors would give rise to damage of this
seal.
An advantage of the screw compressor 1 according to the
invention, that is directly related to this, is that no or
hardly any compressed air is lost when the screw compressor
1 is stopped.
It will be understood that this constitutes an important
energy saving.
Another aspect is that the aforementioned extra non-return
valves in the oil return pipe and in the outlet pipe in the
known screw compressors, must be pushed open during
operation such that large energy losses occur, which do not
occur with a screw compressor 1 according to the invention.
The use according to the invention of a screw compressor
according to the invention is also very advantageous.
It is hereby the intention that when the screw compressor 1
starts up, whereby no pressure has yet built up in the
pressure vessel 51, the self-regulating inlet valve 49,
which is constructed as a non-return valve 49, opens
automatically through the action of the screw compressor 1
and a compression pressure is built up in the pressure
vessel 51.
Then, when the screw compressor 1 is stopped, the non-
return valve 55 on the pressure vessel 51 automatically
closes the air outlet 53 of the pressure vessel 51, and the
inlet valve 49 also automatically hermetically closes the
inlet pipe 48, so that, after the screw compressor 1 has
stopped, both the pressure vessel 51 and the compression
chamber 2 and motor chamber 16 of the screw compressor 1
remain under compression pressure.
Thus little or no compressed air is lost.
Moreover, pressure can be built up much more quickly when
restarting, which enables a more flexible use of the screw
compressor 1 and also contributes to the more efficient use
of energy.
When restarting the screw compressor 1, whereby there is
still a compression pressure in the pressure vessel 51, the
inlet valve 49 first closes automatically until the
compressor rotors 4 and 5 reach a sufficiently high speed,
after which the self-regulating inlet valve 49 opens
automatically under the suction effect created by the
rotation of the compressor rotors 4 and 5.
The present invention is by no means limited to the
embodiments of a screw compressor 1 according to the
invention described as an example and shown in the
drawings, but a screw compressor 1 according to the
invention can be realised in all kinds of variants and in
different ways, without departing from the scope of the
invention.
Claims (33)
1. Screw compressor that at least comprises the following 5 elements: - a compression chamber that is formed by a compression housing in which a pair of meshed helical compressor rotors in the form of a screw are rotatably mounted, which have rotor shafts that extend along a first axial direction and 10 a second axial direction that are parallel to one another; - a drive motor that is provided with a motor chamber formed by a motor housing, in which a motor shaft is rotatably mounted that extends along a third axial direction and that drives at least one of the 15 aforementioned two compressor rotors, wherein the compression housing and the motor housing are connected directly to one another to form a compressor housing, whereby the motor chamber and the compression chamber are not sealed off from one another and whereby the 20 screw compressor is a vertical screw compressor whereby the rotor shafts of the compressor rotors as well as the motor shaft extend along axial directions that are at an angle with or transverse to the horizontal plane during normal operation of the screw compressor, whereby the compression 25 housing forms a base or bottom section of the compressor housing, and whereby the motor housing forms a head or top section of the compressor housing, wherein the compressor rotors are supported in the compressor housing by means of one or more bearings and the 30 motor shaft is supported in the compressor housing by means of one or more motor bearings, and wherein the screw compressor is provided with a fluid, with which both the drive motor and the compressor rotors are cooled and/or lubricated, whereby the screw compressor is provided with a cooling circuit for cooling both the drive 5 motor and the screw compressor and through which fluid can flow from the head of the compressor housing to the bases of the compressor housing, whereby the screw compressor is provided with a lubrication circuit for lubricating the motor bearing or the motor bearings as well as the inlet 10 bearings and whereby the cooling circuit and the lubrication circuit are connected to a return circuit for the removal of fluid from the outlet in the base of the screw compressor and for returning the removed fluid to the head of the compressor housing.
2. A screw compressor according to claim 1, characterised in that the rotor shafts of the compressor rotors, as well as the motor shaft during normal operation of the screw compressor extend along axial directions that are vertical.
3. Screw compressor according to claim 1 or 2, characterised in that the motor shaft is directly coupled to one of the rotor shafts of the compressor rotors and extends along an axial direction in line with the axial 25 direction of the rotor shaft of the compressor rotor concerned.
4. Screw compressor according to claim 1 or 2, characterised in that the motor shaft also forms the rotor 30 shaft of one of the compressor rotors.
5. Screw compressor according to any one of the previous claims, characterised in that the drive motor is an electric motor with a motor rotor and a motor stator. 5
6. Screw compressor according to claim 5, characterised in that the electric motor is equipped with permanent magnets to generate a magnetic field.
7. Screw compressor according to claim 6, characterised in 10 that the inductance of the electric motor along the direct axis differs sufficiently from the inductance of the electric motor along an axis perpendicular to the direct axis, in order to be able to determine the position of the motor rotor in the motor stator by measuring the 15 aforementioned inductance difference in the vicinity outside the compressor housing.
8. Screw compressor according to any one of claims 5 to 7, characterised in that the electric motor is a synchronous 20 motor.
9. Screw compressor according to any one of the claims 5 to 8, characterised in that the drive motor is of a type that can withstand the pressure inside the compression chamber.
10. Screw compressor according to any one of the claims 5 to 9, characterised in that the drive motor is of a type that can generate a sufficiently large start-up torque to start up the screw compressor when the compression chamber 30 is under compressor pressure.
11. Screw compressor according to any one of the previous claims, characterised in that the compressor rotors have a high pressure end that are supported axially and radially in the compressor housing by bearings, by means of one or 5 more outlet bearings.
12. Screw compressor according to any one of the previous claims, characterised in that the compressor rotors have a low pressure end that is only supported radially in the 10 compressor housing by bearings, by means of one or more inlet bearings.
13. Screw compressor according to any one of the previous claims, characterised in that the motor shaft, at the end 15 opposite the driven compressor rotor, is supported axially and radially in the compressor housing by means of one or more motor bearings.
14. Screw compressor according to claim 13, characterised 20 in that the motor shaft is supported in the compressor housing at its end opposite the driven compressor rotor by bearings, by means of a motor bearing that is a ball bearing, and which moreover is equipped with tensioning means for exerting an axial pre-load on the ball bearing, 25 and this pre-load is oriented along the axial direction of the motor shaft.
15. Screw compressor according to any one of the previous claims, characterised in that the compression chamber is 30 provided with an inlet for drawing in air, that is provided near a low pressure end of a compressor rotor, and these low pressure ends are the ends of the compressor rotors that are the closest to the head of the compressor housing, as well as an outlet for removing compressed air, that is provided near a high pressure end of a compressor rotor, 5 and these high pressure ends are the ends of the compressor rotors that are the closest to the base of the compressor housing.
16. Screw compressor according to any one of the previous 10 claims, characterised in that the cooling circuit consists of cooling channels that are provided in the motor housing and of the compression chamber itself.
17. Screw compressor according to claim 16, characterised 15 in that the cooling channels at least partially extend along the first, second and third axial directions.
18. Screw compressor according to any one of the previous claims, characterised in that the fluid is driven through 20 the cooling channels under a compressor pressure generated by the screw compressor.
19. Screw compressor according to claim any one of the previous claims, characterised in that the cooling circuit 25 consists of cooling channels that are provided in the motor housing and of the compression chamber itself, and in that the aforementioned lubrication circuit consists of one or more branches of the cooling channels in the motor housing for supplying fluid to the motor bearing or the motor 30 bearings, and of outlet channels for the removal of fluid from the motor bearing or the motor bearings up to the inlet bearings from where the fluid can flow in the compression chamber.
20. Screw compressor according to any one of the previous 5 claims, characterised in that the flow of fluid in the aforementioned lubrication circuit primarily takes place under the effect of gravity.
21. Screw compressor according to claim 19 or 20, 10 characterised in that, at the motor bearing or the motor bearings, a reservoir is provided for receiving fluid that is sealed off from the motor shaft by means of a labyrinth seal. 15
22. Screw compressor according to any one of the previous claims, characterised in that the aforementioned return circuit is formed by a set consisting of an outlet pipe provided at the outlet, a pressure vessel connected to the outlet pipe and an oil return pipe connected to the 20 pressure vessel.
23. Screw compressor according to claim 22, characterised in that the outlet pipe is connected to the base of the compressor housing, and the oil return pipe is connected to 25 the head of the compressor housing.
24. Screw compressor according to claim 22 or 23, characterised in that the outlet pipe between the pressure vessel and the screw compressor is free of closing means 30 in order to enable a flow through the outlet pipe in both directions.
25. Screw compressor according to any one of the claims 22 to 24, characterised in that the oil return pipe is free of self-regulating non-return valves.
26. Screw compressor according to any one of the claims 22 to 25, characterised in that the pressure vessel has an air outlet that is provided with a non-return valve. 10
27. Screw compressor according to any one of the previous claims, characterised in that during the operation of the screw compressor, the fluid is driven through the return circuit from the base to the head of the compressor housing as a result of a compressor pressure generated by the screw 15 compressor itself.
28. Screw compressor according to any one of the previous claims, characterised in that the majority of the flow of fluid, that is returned via the return circuit, flows 20 through the cooling circuit and only a fraction flows through the lubrication circuit.
29. Screw compressor according to claim 20 when dependent on claim 15, characterised in that the compressor rotors 25 have a high pressure end that are supported axially and radially in the compressor housing by bearings, by means of one or more outlet bearings, and in that a lubrication circuit is provided in the base for lubricating the outlet bearings, consisting of one or more supply channels for the 30 supply of fluid from the compression chamber to the outlet bearings, as well as one or more outlet channels for the return of fluid from the outlet bearings to the compression chamber.
30. Screw compressor according to any one of the previous 5 claims, characterised in that the screw compressor is provided at its inlet with an inlet valve that is a non- controlled or self-regulating valve.
31. Screw compressor according to claim 30, characterised 10 in that the inlet valve is a non-return valve.
32. Screw compressor according to claim 1, substantially as herein described with reference to any embodiment disclosed.
33. Screw compressor substantially as herein described with reference to any embodiment shown in the accompanying drawings.
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
BE2012/0118 | 2012-02-28 | ||
BE2012/0118A BE1020311A3 (en) | 2012-02-28 | 2012-02-28 | SCREW COMPRESSOR. |
PCT/BE2012/000033 WO2013126970A1 (en) | 2012-02-28 | 2012-06-27 | Screw compressor |
Publications (2)
Publication Number | Publication Date |
---|---|
NZ627478A NZ627478A (en) | 2017-03-31 |
NZ627478B2 true NZ627478B2 (en) | 2017-07-04 |
Family
ID=
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