DE7231399U - Oil-lubricated rotary compressor - Google Patents

Description

The invention relates to an oil-smeared rotary compressor with a suction chamber, an idling mechanism that allows intake air during operation of the compressor to be introduced into the suction chamber and the introduction of the intake air during the no-load operation of the compressor block, with at least one pressure chamber, which is in communication with the suction chamber, with at least one corresponding one Rotor, which is arranged in the pressure chamber and driven by a drive for compressing the introduced air and for discharging it

lonkkonltn: H Aufhduxr,

'Poilich »dtVonloMünchin4 <S212

the compressed air from the pressure chamber is driven, with scanning devices for scanning the working conditions of the Compressor and for the generation of two signals that control the load operation and the load-free operation, with actuating devices, which respond to these two signals and control the idling mechanism in the sense of opening or blocking, with an outlet chamber, which is in communication with the last pressure chamber and with an air tank, with oil circulation devices for circulating the lubricating oil between the air tank and the at least one pressure chamber through the outlet chamber for safety a uniform rotation of the at least one rotor and for cooling the compressed air, and with a first check valve, which allows the discharged air and the lubricating oil in the outlet chamber to enter the air reservoir when the pressure in the The outlet chamber is above the one in the air tank, but blocks the passage of the discharged air and the lubricating oil, when the pressure ratio is reversed

The invention relates in particular to an oil-lubricated rotary compressor, in which a rotor or rotors in load-free operation rotated within a corresponding pressure chamber or pressure chambers without intake air entering.

There are two types of idle devices used for rotary compressors such as screw or vane compressors will. Idle or relief devices are widely used to control the flow rate of the Intake air is used and is generally divided into two categories, one the intake throttles and the other the Includes suction port slide.

Compressors with suction passage slide members require a very high degree of accuracy in the dimensions of their sliding parts,.

-3, p.73

since these parts may be connected directly to the screw rotors or leaves come into contact that are rotating at a very high speed. In addition, their structure and their system so complicated that the manufacturing cost is high. Therefore, this type of idling mechanism for compressors is used for general Application that nuts work in different conditions, hardly used.

On the other hand, intake throttle idle organs enable a compressor and a compressor system to be manufactured easily and are constructed to be durable, and the manufacturing cost is much lower. In addition, this is an idle organ Art suitable for almost all working conditions. For these reasons, the majority of rotary compressors are such Idle organs provided. However, they have the significant disadvantage that the power consumption in no-load operation of the compressor is not below 50 to 70% of that of normal or full load operation drops.

The invention is therefore primarily directed towards an oil-smeared one Rotary compressor with intake throttle to create at which minimizes the power consumption of the compressor in load-free operation. In particular, the causes should be eliminated due to which a rotary compressor consumes unnecessary drive power.

The invention builds on the plague position according to the invention, that the main reason for unnecessary power consumption in no-load operation is based on the back pressure on a rotor or exerted on rotors by the lubricating oil and compressed or discharged air contained in the final compression chamber and discharge chamber of the compressor remain. Because of this back pressure, the lubricating oil and ^ die-compressed Air is repeatedly sucked in and released and thereby call out unfavorable Effects such as excessive power consumption, oil impact, and wear of moving parts. These unfavorable Phenomena do not have a seriously detrimental effect on the power consumption of compressors that are small and through an internal combustion engine can be driven. That's because

• ft ·

Internal combustion engine easily durc

the output power eiiiöx · internal combustion engine slightly Control of the fuel inlet flow rate can be controlled. However, the problem of power consumption is increasing Significant when the drive source is an AC motor that runs at constant speed under load and idle mode turns.

The compressor according to the invention of the above type is characterized through a line for connecting the outlet chamber with the air tank, through suction elements within this line for the forced suction of the in the outlet chamber in Idle operation remaining, released air and the Schmiaröis remaining there and through. Valve organs in the line that respond to two signals from the scanning devices and the line open in idle mode and close in load mode.

According to a first feature of the invention, therefore, a large amount of lubricating oil and compressed air both in the last pressure chamber and the exit chamber have remained, forcibly removed without any special device, so that independent a counterpressure on the eotor or the rotors is released by the speed of the compressor. This forced suction The mixture of oil and air is done by adding the mixture is pumped into an air tank in which the oil content is separated from the mixture and the separated clean Air is stored.

On the other hand, the supply of oil is sufficient for the Lubrication of the moving parts of the compressor in idle mode. Because the compressor is idling during this operation runs and no intake air enters, its moving parts do not generate any significant heat. In particular, he needs Compressor not oil for flushing the compressed air, but

only for lubrication. By reducing the in the compressor Introduced amount of oil in idle operation can therefore save a considerable part of the power, which is otherwise to drive an oil circulation device or oil pump or Can be used to move excess oil. The predetermined amount of oil supply may preferably be less than 50 $ of the amount of normal load operation.

When the relief mechanism is in operation, it is not necessary to check the oil content of the air in the air reservoir because no air is emitted, and it is also unnecessary to recover the oil, which-by-means-an oil separator from— occurs because the amount of the separated oil is significantly reduced because the amount of the introduced oil in view of the foregoing Embodiments is reduced. In order to save power, it is therefore advantageous to use the oil return to interrupt the oil collected in an oil sump.

The features and advantages mentioned above relate to the power savings during idle operation, while the the following aspects, the power savings during load operation concern, as will now be explained in more detail.

In an oil-lubricated compressor which has the above features, it is not necessary to suck the lubricating oil and the discharged air from the discharge chamber during full load operation, and therefore it is expedient and advantageous to reduce the inlet and outlet flows of the oil recovery pump during this operating situation to interrupt. Therefore, a back pressure which could otherwise be exerted on the recovery pump is essentially eliminated, and at the same time the power used to drive the pump can be reduced in full load operation.

Furthermore, the oil circulation device or oil pump, which the Lubricating oil supplies the moving parts during full load operation, also for drawing off or recovering the mixture of oil and released air, which are displaced in the outlet chamber

remains, in ien "air reservoir used during idle operation will. An additional oil recovery pump is therefore not required, as the lubricating oil enters the compressor through the Difference between the high pressure in the air reservoir and the reduced pressure in the compression chamber or chambers can be sucked.

Further details, features and advantages of the invention emerge from the following description of exemplary embodiments with reference to the accompanying drawing.

Pig. 1 is a schematic representation of an exemplary embodiment of the invention for minimizing power consumption an oil-lubricated two-stage rotary screw compressor with a suction throttle relief mechanism;

Pig. 2 corresponds to Pig. 1, however, shows another embodiment of the invention.

To simplify the description, the structure of the power saving system 10 of the present invention and of the oil-lubricated rotary compressor 11, which is equipped with this system 10, described together with its operation will.

In normal or full load operation of the compressor 11, the working fluid or the air is drawn into an intake chimney 14 in a conventional manner through an air cleaner 12 and an intake inlet 13, when a relief mechanism or an intake throttle valve 15 is open. This intake air is then passed into a first pressure chamber 16 for the first compression stage, within a first helical rotor 17 of which is arranged. The rotor 17 is rotated by a drive or AC motor 18, so that the introduced intake air is compressed and the compressed air is expelled. This compressed air becomes further compressed in a second pressure chamber IS, within which a second rotor 21 of the same type is arranged, which rotates together with the first rotor 17. Those in that order Air compressed in two stages is fed into the exit chamber

released and * "can be in an air tank 23 via a check valve 24 flow when the check valve 24 due to the lack of a pressure difference between the outlet chamber 22 and the air tank 23 is open.

At the same time, the lubricating oil is through an oil circulation device or oil pump 25 circulated between the bottom of the air tank 23 and the two pressure chambers 16 and 19, so that ensured is that the two rotors 17 and 21 coupled to one another rotate evenly and the compressed and discharged air is cooled. The lubricating oil is also the other moving Parts of the rotary compressor 11 supplied, however this lubrication should not be described here. The oil pump 25 can preferably be driven by the electric motor 18 in coaxial connection with the rotors 17 and 21 driven will. The oil is introduced in this way by the oil pump 25 in the pressure chambers 16 and 19 and compressed with the Air mixed. After the lubrication and cooling have been carried out, the lubricating oil is mixed with the in the form of drops compressed .uuft through the outlet chamber 22 into the air tank 23. The larger drops of oil fall in this air tank 23 down onto the bottom 26, while the smaller drops go over a partition wall 27 and through an oil separator 28 are deposited. In this way the oil content in the mixture is separated from the air and at the bottom 26 and collected in an oil sump 29. On the other hand, it is cut off Air is stored in the air reservoir 23 for further use via the valve 31.

During this normal or full load operation, the scanning device generates 32 for sensing the working conditions of the rotary compressor 11, a load signal that the load operation controls. The sensing of the working conditions can be carried out by measuring the pressure of the delivered or the sucked in air. For this purpose, the scanning device can have an inlet 32a on the air tank 23 or on the suction chamber 14 be provided. In this embodiment, the Inlet 32a attached to the air tank 23. The load signal,

-S-

which can be a pneumatic, electrical or mechanical signal, arrives via a line 33 to an actuating element 34, by means of which the suction throttle valve 15 is held open pneumatically, electromagnetically or mechanically. If this throttle valve is kept open during the load operation, the intake air is continuously introduced into the pressure chambers 16 and 16, as has been described above.

The load signal also arrives via a line 35 to a valve 36, which opens a fluid line 37. When the fluid line 37 is kept open in this way in full load operation, the lubricating oil that has been accumulated in the oil sump 29, into the suction chamber 14 and consequently into the pressure chambers 16 and 19 by the difference between the high pressure in the air tank 23 and the negative pressure in the suction chamber 14. The valve 36 can also be pneumatic, electromagnetic or be mechanical. Its structure is known in detail.

In the oil circulation line of the oil pump 25, denoted by 38 is, a control member or valve 39 is provided, which also responds via a line 41 to the load signal and is full is kept open. This oil control valve 39 can be a vertically opening or sliding slide valve. It will be accordingly opened to the load signal and allows oil lubrication with a controlled normal quantity that is fed into the pressure chambers 16 and 19 is injected. This valve is shown as a pneumatic valve, but can also be an electromagnetic or be a mechanical valve. In the oil circulation line 38 can preferably an oil cooler 42 may be provided which cools the lubricating oil passing through.

On the other hand, when the pressure in the air tank 23 rises due to the work of the rotary compressor 1 1 and a predetermined one Exceeds the height, the scanning device 32 terminates the generation of the load signal and starts generating the idle signal, that controls the idle operation. This idle signal is passed via line 33 to the actuator 34,

so that the throttle valve 15 is closed. In this eye-r look, the throttle valve 15 is moved to the left (Fig. 1) and closes the Ansai.igeinle.ß 'i? - consequently the entry of the Blocked intake air, so that the rotors 17 and 21 without entry of intake air circulate. The idle signal is also sent to the Control valve 39 given in order to reduce the oil supply to the pressure chambers and 19 during the idling operation.

During the idling operation thus effected, the back pressure that could be exerted on the rotors I7 and 21 is forcibly removed from the last or second pressure chamber I9 and the outlet chamber 22 according to the main feature of the invention. For this purpose, the system 10 comprises a line 43 which creates a fluid connection between the outlet chamber 22 and the air tank 25, extraction devices or an oil return pump 44 _T which is arranged in the line 43 and a valve arrangement which is also located in the Line 43 is located and two check valves 45 and 45 comprises. The pump 44 is rotated by the alternating current motor 18 in coaxial connection with the oil pump 25 and forcibly guides the mixture of discharged air and lubricating oil, which has remained in the discharge chamber 22, into the air tank 23, but this suction operation is only carried out when the two Check valves 45 and 46 are released on the basis of the idle signal via lines 47 and 48. For the purpose of explanation only, the scanning device 32 is shown separately in the figure on the right-hand side. During full load operation, however, the check valves 45 and 46 are pneumatically, electromagnetically or mechanically closed by the load signal and thus exclude any other counter pressure which could also be exerted on the pump via its inlet 44a and its outlet 44b. Thus, the rotation of the pump 44 does not result in a

«III ·« ·· I

-10-

18 ac motor unnecessary consumption along with the forced removal of the mixture of air and oil

CA IA ^v "* · * V / CA | ^ fcA IA ^ J ** *» ^ MVAkMl * W * ^ * · »rf ^ ** * ^- * ^ *** ^ ** · *» · ^

see the outlet chamber 22 and the air tank 25 closed.

The idling signal is also fed to the control valve 39 by the flow rate of the lubricating oil to be injected to a predetermined value, preferably below 50% that of the load operation is reduced. In this way, excessive pump performance and unnecessary oil can be saved and the rotary compressor 11 does not have to consume unnecessary power to move the excess oil and to circulate even if the speed of the compressor is constant. as is the case with the use of an AC motor 18 of the Case is.

The idle signal continues to be sent to valve 56, so that the fluid line 57 is closed and thus the return of the lubricating oil in the oil sump 29 is blocked. this also contributes to reducing the power requirement during of idling operation.

Referring to FIG. 2, a detailed description of parts that correspond to those of FIG. 1 is omitted will. In this second embodiment, no oil return pump like the pump 44 according to FIG. 1 is provided, and the oil pump 25 'works for two purposes, that is, to circulate the lubricating oil in the load operation and to return the mixture of oil and air from the outlet chamber 22 in the idle operation. In this context, pay attention pointed out that all components and modes of operation of the system 10 * - with the exception of those described below - coincide with those of FIG. 1 and consequently not explained again will.

7231311-8.1 »

the • · · ■ · I ■ in the • · · or .1 ' '"■' Full load operation • III
■ I>
I: ' -11- 11th normal if Rotary compressor

operates, the valves 51 and 52 are due to the let signal, which is fed through lines 54 and 48 'is opened. At the same time the other valves 4-5,46 and 53 are due to the on lines 4-7 ', 48' and 54 supplied signal closed held. The lubricating oil is polarized by the common oil pump 25 'to the moving parts of the rotary compressor 11 from the bottom 26 of the air tank 2 $ over the oil cooler 42, the valves 51 and 52 and the oil circulation line 38 is supplied.

On the other hand, when idling occurs, the valves are 45, 46 and 53 opened by the idle signal while the valves 51 and 52 are closed. In this case, the lubricating oil is lubricated and lubricated in the pressure chamber 16 and 19 via a non-numbered oeipass line that connects the valve 53 includes, initiated. This introduction of the lubricating oil is performed automatically, that is, it is performed due to the difference between the high pressure in the air tank 23 and the negative pressure in the pressure chambers 16 and 19 · That is based on the fact that a negative pressure by forcibly returning the back pressure, which is in the outlet chamber 22 without would form the oil and air return line with the valves 45 and 46 and the oil pump 25 'is generated. The dimensioning of the so supplied lubricating oil can through suitable, not shown here openings or the like. be effected, if necessary to the associated oil passage are to be provided.

In this embodiment, the control valve 39 used in the oil circulation line, like the valve of the first Embodiment according to Pig. 1, but may be desired if necessary replaced by another dosing device

7231388-8.171

will. Such a dosing or restriction device is for example an opening 39 ′> those provided in line 4-3 is, or the line 'i-3 itself, -.v if it is with a restricted Passage can be provided.

In this way the power requirement of the compressor can be reduced when idling can also be minimized by using a single common oil pump. The valves 5t »52 and 53 can also be designed pneumatically, electromagnetically or mechanically.

As has been explained in detail, the inventive systems 10 and 10 'are able to reduce the power consumption of a Oil-lubricated rotary pump by swongly deducting the delivered Air and lubricating oil in the last pressure chamber and remained in the exit chamber to be reduced to a minimum. A further reduction in the power requirement during idling operation takes place in that the amount of oil supplied to the moving parts of the compressor is reduced and that the return of the oil collected in the oil sump is interrupted. Both measures avoid that excess oil gets into the pressure chamber or the pressure chambers.

In addition to the effects mentioned above, the power requirement is increased also reduced during normal or full load operation by releasing the back pressure on an oil return pump ben, and the performance and manufacturing costs are reduced κ graced by using a common oil pump for two purposes * ■ so that the recirculation pump can be saved. O"

In the case of a single-stage compressor, the power requirement in idle operation in compressors without the system according to the invention is 70% of the power requirement in full load operation, as against 18% in compressors with the system according to the invention.
In the case of two-stage compressors, on the other hand, the corresponding words are 50% for compressors without this system and 18% for compressors with this system.

Claims (2)

Protection claims 1. Oil-lubricated rotary compressor with a suction chamber, an ilie air supply to the suction chamber in idle mode "Idle mechanism that blocks and releases during load operation, at least one in the direction of flow Compression chamber located behind the suction chamber, in which a driven rotor runs, with one in the direction of flow outlet chamber located behind the compression chamber, which has a non-return valve with an air tank is connected, and with a sensing device responsive to the air pressure in the air tank, with which between idle and load operation can be switched, characterized in that the outlet chamber (22) with the The air tank (23) is connected via an additional connecting channel (43) bypassing the check valve (24), in which a suction device (44) acting in the direction of the air tank and at least one of the scanning device (32) are arranged lockable valve during load operation. Bank accounts 1H. Aufhaut ", MOndi" ■ Poitidiedekonto Munich 44212 —2— 2. Rotary compressor according to claim 1, characterized in that the suction device (44) one with its shaft coaxial with the rotor (17 »21) and its Drive (18) arranged oil pump is. 3- rotary compressor according to claim 1 or 2, characterized characterized that in the air feehälters (25) one between the air inlet and the air outlet (31) lying oil separation device (28) is arranged that an oil sump (29) for the separated oil and that a the Oil sump with the suction chamber (14) connecting channel (37) is provided in which a valve is arranged, which of the The scanning device (32) is locked in idle mode and open in load mode.