EP1163451B1 - Rotary helical screw-type compressor - Google Patents

Abstract

The drive gear 19, 21 and the synchronizing gear 25, 27 for the two rotors 9,11 of a screw compressor are both located at the pressurized end of the rotor housing 3. At the suction end of the rotor housing 3 is only the bearing 53 for the suction side shaft journal 55, 57 that is free of oil lubrication. Inlet openings 13 in a suction side inlet housing are located in such a way that the intake air cools the oil-free shaft bearing 53. Each shaft journal has a tool interface 63 accessible through the inlet housing on which to attach a rotating tool. The inlet housing 4 can be removed from the shaft journal 55, 57 together with the bearing 53 and seal 87, for example to exchange the bearing, without having to remove the rotors 9, 11 or without throwing off their adjustment.

Description

The invention relates to a screw compressor in the Preamble of claim 1 mentioned type. The invention is preferred, but not exclusively applicable to a screw compressor for generating a compressed air flow for the pneumatic transport of bulk goods, and especially one for attachment to one Silo vehicle trained screw processor.

Screw compressors work on the displacement principle Air compressors compared to other types of compressors have beneficial properties they especially for the pneumatic transport of bulk goods make suitable. This applies in particular to so-called dry running screw compressors, where the by a synchronous gear synchronized screw rotors no contact with each other and with the surrounding housing parts to have. There is therefore no lubrication in the compression chamber required so that they are kept oil-free can and therefore any contamination of the compressed air with oil is avoided. Due to the contact-free running of the rotors there is no wear in this area either the lifespan is reduced and there is no abrasion the contaminated air can contaminate. screw compressors are due to their operating characteristics especially suitable for realizing high pressure ratios and are insensitive to short-term pressure increases, caused by the blockage of the compressed air Pipeline could be caused. Finally have they lighter weight and small size, what makes them special for mobile use e.g. B. suitable for silo vehicles makes.

In many previously known screw compressors, in particular for the use of silo vehicles is the drive gear for the rotors at one end and the synchronizing gear arranged at the other end of the rotors. oil lubrication is therefore on the pressure side as well as on the suction side End of the rotors required. Sucking the Air comes through a filter and / or a silencer, which are designed as separate units from the compressor housing and with the compressor housing via a suction line are connected, bypassing the synchronizing gear near the suction end of the rotor housing in this ends. The presence of oil lubrication on the Suction side of the rotor housing is undesirable because it is the Risk of air contamination with oil increases. Training of the intake filter and / or muffler separately the demand runs from the actual compressor housing after compact, robust and weight-saving construction opposite.

GB-A-2 299 622 discloses a screw compressor according to the preamble Claim 1. By arranging both the drive and the synchronizing gear on the pressure side of the rotor housing of this screw compressor can be oil lubricated at the suction end of the rotor housing to be dispensed with. Furthermore, the suction side Shaft journal of the rotors and their bearing arrangement surrounding Area of the suction-side housing cover directly for the inflow of air into the compressor room can be used. A suction filter and / or Intake silencer is not available, however.

The invention has for its object by an improved Construction of the screw compressor in the area a simplified of the suction end of the compressor housing and improved air intake with filtering and / or sound absorption and a compact design of the compressor.

The achievement of the object is in claim 1 specified. The sub-claims relate to advantageous further refinements of the invention.

According to the invention, the intake filter and / or the intake housing containing the intake silencer directly attached to the suction end of the compressor housing, resulting in a compact, space-saving and particularly robust construction for mobile use.

Fig. 1

eine perspektivische Ansicht des Kompressors mit Ansaugfilter, von der Seite gesehen;

Fig. 2

einen Vertikalschnitt durch den Kompressor von Fig. 1;

Fig. 3

einen horizontalen Schnitt durch den Kompressor in der die beiden Rotorachsen enthaltenden Ebene;

Fig. 4

eine weitere perspektivische Darstellung des Kompressors in Untersicht, vom saugseitigen Ende her gesehen, bei abgenommenem Ansauggehäuse und Ölbehälter;

Fig. 5

ein Detail der perspektivischen Ansicht gemäß Fig. 1, mit einer geänderten Ausführungsform des Ansauggehäuses;

Fig. 6

ein vergrößertes Detail der Schnittdarstellung von Fig. 2 im Bereich der saugseitigen Rotorlagerung.

Fig. 7

ein vergrößertes Detail der Schnittdarstellung von Fig. 3 im Bereich der druckseitigen Rotorlagerung.

An embodiment of the compressor according to the invention is explained in more detail with reference to the drawings. It shows:

Fig. 1

a perspective view of the compressor with suction filter, seen from the side;

Fig. 2

a vertical section through the compressor of Fig. 1;

Fig. 3

a horizontal section through the compressor in the plane containing the two rotor axes;

Fig. 4

a further perspective view of the compressor from below, seen from the suction end, with the suction housing and oil tank removed;

Fig. 5

a detail of the perspective view of Figure 1, with a modified embodiment of the suction housing.

Fig. 6

an enlarged detail of the sectional view of FIG. 2 in the area of the suction-side rotor bearing.

Fig. 7

an enlarged detail of the sectional view of Fig. 3 in the region of the pressure-side rotor bearing.

All figures are the same or correspond to each other Parts labeled with the same reference numerals.

The housing of the compressor shown in Figs. 1-4 is composed of the following main parts: one Gear housing 1, a rotor housing 3, an inflow housing 4, a suction housing 5 and an oil tank 7. In the rotor housing 3 are two rotors, namely a main rotor 9 (profile teeth) and a secondary runner 11 (profile gaps) rotatably mounted with their helical teeth and interlock tooth gaps while sealing Form chambers, which are in the rotation of the rotor Move and reduce the axial direction and thereby the suctioned Compress air. In operation, the rotors so driven that the right end in Figs. 1-3 Suction side is. Here air gets through at the front of the Rotor housing 3 provided intake openings 13 sucked. The air is from the interlocking teeth and tooth gaps of the rotor pair is conveyed to the left in the axial direction and occurs as compressed air at the pressure end the rotors at an upward pressure outlet 15 out. The principle of operation of a screw compressor is known and will not be explained here.

The gear housing 1 has the shape of a disk-like Stand. In it, the drive shaft 17 is in bearings 16, 18 of the compressor, whose from the housing cover 49th protruding shaft journal 17a to a not shown Rotary drive is connected. The gearbox 1 also contains a drive gear consisting of a on the drive shaft 17 fixed gear 19 and a fastened on the shaft journal 23 of the secondary rotor 11 Gear 21 through which the rotation of the drive shaft 17th with a suitable gear ratio to the secondary runner 11 is transmitted. Furthermore, in the gear housing 1, d. H. also on the pressure side of the rotors 9, 11, which for the Synchronization of these rotors ensures synchronizing gears housed, consisting of the intermeshing gears 25, 27 on the shaft journal 23 of the secondary rotor or attached to the shaft journal 29 of the main rotor 9 are. The synchronizing gear ensures that the rotors 9, 11 with very little play, but without contact to grab. This makes it possible without any Oil lubrication between the rotors 9, 11, i.e. to realize a dry running compressor. This is especially important if the compressor has any oil residue absolutely free air flow for pneumatic conveying of sensitive goods to be conveyed.

The overall stator or disc-shaped gear housing 1 has on both sides at its lower base cantilevered mounting feet 31 with holes 33 for Fastening screws that secure the entire compressor a suitable pad, e.g. B. a vehicle attached can be.

For the purpose of constant lubrication of the drive gear 19, 21 and the synchronizing gear 25, 27 is in the Gearing area of both gears Lube oil injected, which is constantly circulated by an oil pump 45 becomes. A required supply of oil is in the oil container 7 kept in stock with the interior of the gearbox 1 communicates. With the shaft journals 23, 29 the Rotors 9, 11 cooperate sealing arrangements 35 which the oil access to the rotors 9, 11 and thus to the compression chamber prevent the compressor. These sealing arrangements are explained in detail. Because the drive gear 19, 21 and the synchronizing gear 25, 27 both are arranged on the pressure side of the rotors 9, 11 and the suction side bearings of the rotors are filled with grease, as will be explained, is on the suction side of the rotors (in Fig. 1-3 right) no oil lubrication required. There are therefore no oil lines, as with the usual design of screw compressors, required by the oil of circulate the pressure side to the suction side of the rotor and back can.

As can be seen from FIGS. 1 and 3, the rotor housing 3 on the gear housing 1 by means of a flange connection 37 attached so that it projects freely from the gear housing 1. The oil container 7, which has a flat box shape, is also attached to the gear housing 1 so that it is free of this cantilevered, approximately parallel to the rotor housing 3 and below it. The side walls of the oil container 7 are provided with cooling fins 39. Between the oil tank 7 and the bottom of the rotor housing 3 is a relatively wide air gap 41. With this arrangement of the rotor housing 3 and oil container 7 relative to each other and to the gear housing 1 it is achieved that the heat transfer, in particular heat conduction, from the rotor housing 3 to the oil tank 7 is reduced to a minimum. So that will avoided that when operating the compressor in the rotor housing 3 Heat generated by air compression into one undesired heating of the oil supply in the oil tank 7 leads, although the oil tank 7 directly with the gear housing connected is. Through direct attachment (Flange connection) of the oil tank 7 on the gear housing 1 can this with the gear housing 1 via a communicate large opening 43. There are no separate oil lines.

For the circulation of the oil inside the gearbox 1, or for generating an oil mist, an oil pump 45 is used, which surrounds and is driven by the drive shaft 17 becomes. The housing of the oil pump 45 has a protruding outward Flange 47, which is used to center the gearbox housing 1 attached housing cover 49 is used. The oil pump 45 is with 4 screws 51 (Fig. 3) and associated threaded holes attached to the gear housing 1.

Due to the arrangement of the drive gear 19, 21 and Synchronizing gear 25, 27 on the pressure side of the rotors 9, 11 are only on the suction side Bearing 53 for the suction-side shaft journal 55, 57 in one the rotor housing 3 closing inlet inlet 4, in which between the support ribs 14 to the interior of the rotor housing 3 leading inflow openings 13 are formed are. The bearings 53 are with the shaft journals 55, 57 cooperating sealing arrangements 61 upstream, the still to be explained.

The ends of the suction side projecting beyond the bearings 53 Shaft journals 55, 57 of the rotors 9, 11 are in tool engagement for the approach of a turning tool. In the embodiment shown in Fig. 6 there is Tool engagement from two flats 63 for the approach a wrench. Tool intervention can also the shape of a square, hexagon, an internal hexagon or the like. The one with the tool intervention provided shaft journals 55, 57 are by removing one on the inflow housing 4 with the housing cover fastened with screws 65 easily accessible.

By attaching a turning tool to one or both suction-side shaft journal of the rotors 9, 11 it is possible turning them by hand and thereby blocking the Eliminate rotors that can occur when dusty Well, that thanks to the compressed air flow generated by the compressor to be funded as a result of a material setback in the interior of the rotor housing 3 and between the Rotors 9, 11 arrives. By turning the drive shaft journal Such a block can usually not be eliminated since the drive gear 19, 21 a too has high translation.

The inlet openings that close the rotor housing 3 on the suction side 13 inflow housing 4 is at a distance surrounded by a large-volume intake housing 5 (in Fig. 2 and Fig. 3 only indicated by dash-dotted lines), the means Screws attached to a flange 67 of the rotor housing 3 is. In this fastened directly to the rotor housing 3 Intake housing 5 is an intake filter for filtering the intake air and / or a damper for sound absorption. In the embodiment shown in Fig. 1 contains the suction housing 5 a filter 6 made of a suitable porous or air-permeable filter material. The filter lies in an air flow path between an outer suction slot 69 and one arranged in an inner partition 71 Passage slot 73, with suction slot 69 and passage slot are offset from each other so that a longest possible flow path for the air between the Slits 69, 73 is formed by the filter 6.

5 is a modified embodiment of the intake housing 5, in which the through the suction slot 69 sucked in and through the deflection wall 71 Passage slot 73 redirects air e.g. from suitable Flows through perforated plates trained muffler 75, before it gets into the space surrounding the housing cover 69 and through the inflow openings 13 into the interior of the rotor housing 3 flows. It is also possible to use the intake housing 5 so that it is both a filter and also contains a silencer.

An advantage of the direct attachment of a filter and / or a silencer-containing suction housing 5 on the rotor housing 3 such that it is the inflow housing 4 at a distance surrounds is that a separate arrangement of a Filters and / or silencers, and a connecting line between this and the suction side of the compressor can. This makes it particularly simple, compact and robust arrangement achieved. Another advantage is there in that the air sucked into the suction housing 5 Outside of the inflow housing containing the shaft journal bearings 4 flows around and cools before passing through the Inflow openings 13 into the interior of the rotor housing 3 entry. This ensures effective cooling of the suction side Rotor bearing achieved.

Fig. 6 shows the storage in an enlarged sectional view and sealing the shaft journal 55 of the rotor 9 in the inflow housing 4. The shaft journal 57 of the other rotor 11 is mounted and sealed in an analogous manner. The shaft journals provided with tool engagement (flats 63) 57 is formed in the manner of a hub Middle part of the inflow housing 4 by means of a roller bearing 53 stored between a shoulder of the shaft journal 57 and one engaging in an annular groove of the shaft journal Circlip 83 is arranged. Because on the suction side the rotors 9, 11, as stated above, no oil lubrication Rolling bearing 53 is preferably to take place as an encapsulated bearing with a lifetime grease filling trained so that there is no subsequent lubrication needed. Following the roller bearing 53 is on the shaft journal 57 a race 85 attached, preferably shrunk. The race 85 which e.g. a commercial one The race for a rolling bearing can be made of steel specially hardened peripheral surface. Two work with this Sealing lips of a lip sealing ring 87 together, the Seals the interior of the rotor housing 3 against the roller bearings 53. On the side facing the rotor housing 3 Lip seal ring 87 is between this and an inner shoulder 4a of the inflow housing 4, a protective ring 89 is arranged, the inner periphery of the outer surface of the race 85 with a very small gap, but faces without contact. The protective ring 89 and the lip seal ring 87 are on each other and on the inner shoulder 4a of the inflow housing 4 attached in the bore of the housing, preferably glued.

The function of the guard ring 89 is as follows: The compressor generated during operation by sucking in air on the Suction side and blowing out compressed air at the pressure port 15 a compressed air flow, e.g. for pneumatic transport of dusty goods can serve. In the event of malfunctions there may be a backlash of compressed air from the pressure side to the suction side of the rotors, whereby there is a risk of airborne particles of the dusty material in the rotor housing 3 and out this up to the shaft journal of the rotors. in the In the event of such a material kickback, the guard ring protects 89 the lip seal 87 in front of that dust particles underneath the sealing lips of the lip seal ring 87 and impair the sealing effect.

The one shown in Fig. 6 and described above suction-side bearing arrangement has the further advantage that it can be withdrawn from the shaft journal 57 without the rotor 9 or 11 removed or the precise setting the rotors must be changed to each other. The Remove the bearing and seal assembly from the journal can be done in the following ways:

After removing the suction housing 5, the housing cover 65 of the inflow housing 4 removed, so that the shaft journal 57 is accessible with its locking ring 83. The Circlip 83 is removed. Then the connecting the inflow housing 4 to the rotor housing 3 Screws loosened. Now the entire inflow housing 4 together with the roller bearings 53 contained therein, lip seals 87 and protective rings 89 are removed. Thereby can the suction-side roller bearings 53, those Parts are due to the limited life of their Grease filling is most likely to need to be replaced, easily be replaced without the rotors 9, 11 in their Adjustment to each other and to the housing changed or even expanded should be.

7 shows in a sectional view corresponding to FIG. 3, but on a larger scale the storage and sealing of the pressure side shaft journal 29, 23 of the rotors 9, 11 am pressure-side end of the rotor housing 3. In the following the bearing and sealing arrangement for the shaft journal 29 of the rotor 9 described. The one for the shaft journal 23 the rotor 11 is completely analog.

The shaft journal 29 is in the pressure-side end wall of the Rotor housing 3 by two roller bearings arranged side by side 91, 93 stored, the so-called angular contact ball bearings are trained. Angular contact ball bearings that are commercially available are ball bearings, the balls of which are from the outside and inner race only on one or the other side of the radial central plane are encompassed. The two angular contact ball bearings 91, 93 are arranged side by side in mirror symmetry. Such an arrangement of angular contact ball bearings has the Property that it is completely free of play in the axial direction. A shaft nut 95 arranged on the shaft journal 29 puts the angular contact ball bearings 91, 93 in the axial direction on the Shafts journal 29 firmly. The outer race of the Angular contact ball bearing 93 lies against an inner shoulder 97 of the Rotor housing 3 on.

Is located between the angular contact ball bearing 93 and the rotor 9 a section of the shaft journal 29 on which a Race 101 attached, preferably shrunk.

This race 101 is made just like the one previously described 6, made of steel with a special hardened peripheral surface. On the surface of the race 101 lie against the sealing lips of a lip sealing ring 103, which the compression space of the rotor housing 3 against the oil-loaded Seals gearbox and bearing area. The hardened and extremely precisely machined, e.g. polished Outer surface of the race 25 results in a particularly wear-reducing Contact surface for the sealing lips of the lips sealing rings 103.

Is located between the lip seal ring 103 and the rotor 9 there is also a labyrinth sealing ring 105 on its inner circumference has several adjacent ring ribs, that of the outer surface of the race 101 with very little Face the gap, but without contact and with this form a labyrinth gap. Although the race 101 normally no contact with the labyrinth sealing ring 105 , it is still advantageous that the Race 101 also over the area of the labyrinth seal 105 extends. The labyrinth gap seal is normal a non-contact seal, but it can be under extreme operating conditions under certain circumstances between the ring ribs of the labyrinth sealing ring 105 and the Race 101 take place. If the race 101 is not would be present, there would be grooves on the shaft journal 29 are generated so that it is damaged and the Rotor 9 becomes unusable. Thanks to the presence of the race 101 only needs the race 101 in such a case to be replaced, so that the rotor 9, otherwise Damage free, can be used again.

Between the labyrinth sealing ring 105 and the lip sealing ring 103 there is an annular relief space 107, which is connected to the atmosphere via a ventilation duct 109 (see FIGS. 7 and 2). The ventilation channel 109 formed in the interior of the rotor housing 3, the so-called lantern, runs downward from a point between the two shaft journals 29, 23 of the rotors 9, 11 and opens at the underside of the rotor housing 3. The opening of the lantern 109 lies at a distance from with the cooling fins 39 provided top of the oil container 7 opposite. A straight access path to the mouth of the lantern 109 from below is blocked by the oil container 7.
Fig. 4 shows a perspective view from below of the compressor with the oil container 7 removed, so that the screw holes 44 for the attachment of the oil container 7 and the large connecting opening 43, through which the oil container communicates with the transmission housing, are visible in the end wall of the transmission housing 1 , 4, the suction housing 5 is removed from the suction-side end of the rotor housing 3, so that there is a clear view of the inflow housing 4 with its supporting ribs 14 and the inflow openings 13 leading to the interior of the rotor housing 3. FIG. 4 also shows the mouth of the lantern (ventilation duct) 109 on the underside of the rotor housing 3. As can be seen from Fig. 4, on both sides of the mouth of the lantern 109 projections 111 are provided on the underside of the rotor housing 3, which the mouth of the lantern 109 against linear access from the Shield side. These projections 111 can be formed by oil drain channels. The mouth of the lantern 109 is thus at a protected location, to which a straight-line access path is neither possible from below (because of the oil container 7) nor from the side (because of the projections 111). This prevents that, for example, when cleaning the compressor by means of a high-pressure spraying device, the high-pressure water jet can be directed directly onto the mouth of the lantern 109, as a result of which water could get into the annular space 107 and thus into the area of the lip sealing ring 103 and the labyrinth sealing ring 105.

As can be explained with reference to FIG. 7, the race 101 attached to the shaft journal 29 additionally serves as a spacing element, which is used to maintain a very precisely dimensioned gap between the pressure-side end face of the rotor 9 or 11 and the end face 113 of the rotor housing 3 facing it serves. For the efficiency of the compressor, what is crucial is the smallest possible and precisely defined gap on the pressure-side end face of the rotor 9 or 11. According to the invention, this gap is set and maintained precisely in such a way that, when the rotor housing 3 is machined, the distance a between the end face 113 facing the rotor 9 and the contact shoulder 97 for the roller bearing 93 is manufactured with very narrow tolerances to a predetermined value , The length b of the race 101, which is used as a spacing element between the roller bearing 97 and the end face of the rotor 9, is also ground with correspondingly precise tolerances to a value which has an oversize compared to the distance a , which is exactly the width of the between Corresponds to rotor 9 and the rotor housing 3 gap to be set. This adjustment of the gap due to the length difference of the distances a and b is possible in that angular contact ball bearings 91, 93 are used according to the invention in a symmetrical arrangement, which, as mentioned, result in a bearing arrangement that is completely free of axial play. Since the contact surfaces between the outer bearing ring and the housing shoulder 97 on the one hand and between the inner bearing ring of the roller bearing 93 and the race 101 on the other hand serve as axially backlash-free reference surfaces, the distance a between the housing shoulders and the length b of the race 101 can be obtained with sufficient precision a correspondingly precise setting of the rotor front gap. The setting of the rotor end gap once obtained is retained even with changes in temperature, since the influence of the different thermal expansion of the rotor housing 3 and the race 101 is negligible. There is no longer any need to adjust the rotor front gap when installing compressors of this type by inserting shims of different thicknesses in accordance with the fluctuations in the manufacturing tolerance.

Claims (5)

1. A screw compressor comprising: two rotors mounted in a rotor housing (3) with parallel axes, that engage one another with screw-shaped teeth and tooth gaps, and that convey air during operation from a suction end toward a pressure end of the rotor housing (3) and thereby compress the air,
      a gear housing (1) located at one end of the rotor housing (3) in which a drive shaft (17) is mounted with drive gears (19, 21) for the rotors (9, 11) and in which oil lubrication is provided for the drive gears,
      and a synchronizing gear (25, 27) that couples the rotors (9, 11) to run together in opposite directions synchronously without touching,
      wherein the drive gear (19,21) and the synchronizing gear (25, 27) are both located in the gear housing (1) on the pressure end of the rotor housing (3), and wherein the bearings (53) for suction side shaft journals (55, 57) of the rotors (9, 11) are free of oil lubrication and are located in an inlet housing (4) that closes off the rotor housing (3) at the suction end and has inlet openings (13) for the air aspirated by the rotors (9, 11) such the section of the inlet housing (4) containing said bearings (55, 57) is cooled by means of the intake air,
      characterized in that that the inlet housing (4) is surrounded in spaced relationship by an intake housing (5) attached to the rotor housing (3) that has at least one intake opening (59) and in which there is located a filter (6) and/or a muffler insert (75) in the flow path of the air from the intake opening (69) to the inlet openings (13).
2. A screw compressor according to claim 1, wherein each of the bearings (53) for the suction side shaft journal (55, 57) of the rotors (9, 11) is an encapsulated roller bearing with a lifetime grease filling.
3. A screw compressor according to claim 1, wherein the inlet housing (4) has holes (66) through which the shaft journals (55, 57) of the rotors (9, 11) can be accessed, and that a tool interface (63) is designed into each shaft journal (53, 55) for engagement by a turning tool.
4. A screw compressor according to claim 1 wherein the inlet housing (4) has holes (66) through which the shaft journals (53, 57) of the rotors (9, 11) can be accessed, and that a retaining ring (83) that secures the bearing (53) to the shaft journal (55, 57) can be accessed through the holes (66) in such a way that the retaining ring (83) can be removed from the shaft journal (55, 57) and then, after removing any attaching screws, the inlet housing (4) and the bearing (53) and any seals (87) can be removed from the shaft journal (55, 57).
5. A screw compressor according to claim 1 wherein each suction side shaft journal (55, 57) is sealed in the inlet housing (4) by means of a lip seal ring (87) that sits against the shaft journal or a race (85) located on the shaft journal, and that between the lip seal ring (87) and the rotor housing is a guard ring (89) that sits opposite the perimeter surface of the shaft journal or race (85) with a minimal separation without touching it.

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