JPH1150987A - Screw compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent oil leakage by a simple means as well as to make a seal member suitable to the long operating time needing no maintenance. SOLUTION: A seal member is provided with two seal rings 13, 14 to be brought in contact with a short shaft 6 under inherent stress and guided in the axial direction at a distance, an oil chamber 15 in which oil is previously filled is provided between the seal rings, a rising pipe 19 extends from an oil chamber 15 to a sucking conduit 20 connected to a suction chamber of a screw compressor, and the rising pipe 19 is opened into the sucking conduit 20 at a higher part than the oil chamber 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an intermittent operation, in particular for supplying compressed air to rail vehicles.
screw compressor, at least one
Screws are provided, and this screw ends on the suction side with a short axis penetrating the partition wall from the suction chamber to the surroundings of the environment, and this short axis has a rotary bearing on the screw side, The present invention relates to a type having a sealing member for a partition wall which is shifted from each other in an axial direction on an environment surrounding side.

[0002]

BACKGROUND OF THE INVENTION Screw compressors, especially for stationary equipment, usually operate in continuous operation. In that case, a relatively low steady-state pressure state is usually generated in the sealing member which is formed as a groove ring or has an L-shaped cross section. Under such favorable operating conditions, the sealing member can achieve a long service life.

On the other hand, in the case of a screw compressor provided for intermittent operation, which is used particularly for supplying compressed air to a rail vehicle, the sealing member must withstand a completely different kind of high load. Screw compressors of this type must maintain a pressure of about 8 to 11 bar in their compressed air reservoir for supplying compressed air to rail vehicles. This type of compressor has a maximum of about 30 per hour during intermittent operation.
Times must be switched on and off. In addition, in the case of the switching off, the screw compressor is stopped. Due to this type of operation of the screw compressor, the sealing member
Each time the compressor is stopped, a pressure of about 9 bar is applied on the screw side by the return expansion of the compressed air and then in the suction chamber,
More multi-stage decompression that occurs with different pressure drop gradients,
For example, up to 2 bar or up to ambient pressure. Thus, the next time the screw compressor is restarted, there may still be several bar pressures in the suction chamber, so that it must be started again under pressure. With this type of actuation, the sealing element must also ensure that oil does not leak from the suction chamber or the rotary bearing. Therefore, the sealing member has a considerable preload or preload (Vorspannun
g), which additionally has the risk that the sealing element can be pressed and deformed under high differential pressure loads. The sealing element is thus at risk of wear and damage, and must be replaced after a relatively short operating time. However, this replacement of the seal member may require an extremely wide range of, and therefore expensive, assembling work, even if the material cost is relatively low, depending on the mounting situation of the screw compressor. These assembling operations result in a correspondingly long stopping time of the rail vehicle.

[0004]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a screw compressor of the type described at the outset with simple means, with regard to the sealing member, which is suitable for a long operating time without maintenance and which has no oil leakage. That is, it is configured to be prevented.

[0005]

SUMMARY OF THE INVENTION In order to solve this problem, according to an embodiment of the present invention, a sealing member is provided with two axially guided seals which contact a short axis under an intrinsic stress. An oil chamber pre-filled with oil is provided between the seal rings, from which an upright pipe leads to a suction conduit connected to the suction chamber of the screw compressor. And in the suction conduit,
The opening is higher than the oil chamber.

[0006] Further advantages and advantageous features of the invention are set out in the following claims. .

[0007]

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described by way of an embodiment shown in the accompanying drawings.

FIG. 1 shows the ends of the two screws 1 and 2 of the screw compressor based on the conventional configuration on the suction chamber side. The suction chamber 3 of the compressor is provided in a casing 4 having a partition wall 5 on the end face side with respect to the environment. A suction pipe (not shown) is opened in the suction chamber 3 like a general-purpose type, and air compressed by the screw compressor flows into the suction chamber 3 from the surrounding environment through the suction pipe. it can. Screw 1 is short axis (Wellenstummel)
Ending at 6, the short axis 6 penetrates the bulkhead 5 and is rotatably supported in the bulkhead 5 by a rolling bearing 7. A bearing cover 8 is held on the partition wall 5 around the environment by fixing means (not shown), for example, screws. The bearing cover 8 has a hole 9
And the short axis 6 penetrates this hole with play. A seal ring 10 is held in the hole 9, and the seal ring 10 has an intrinsic stress or a residual stress (Eigenspan).
nung) in contact with the short axis 6. The sealing ring can have in its contact area a sealing lip facing the rolling bearing. On the environmental side, the bearing 6 is connected to a drive motor (not shown) for the screw compressor.
The screw 2 has a very short minor axis 11,
1 is rotatably supported in the partition wall 5 via another rolling bearing 12. The bearing cover 8 covers the rotation bearing of the screw 2 densely.

In this respect, the following points are recognized in the screw compressor shown in FIG. 1 configured as a general-purpose type. That is, when the screw compressor is stopped during the above-described intermittent operation required for the supply of compressed air to the rail vehicle, first, the seal ring 10 is provided between the suction chamber 3 and the surrounding environment. , For example 9 bar, and then during a screw compressor downtime, this differential pressure can be reduced, possibly in multiple stages, with different pressure drop gradients, but The difference is that when the screw compressor is restarted, a differential pressure of about 2 bar is still built up in the seal ring 10. In the subsequent compression operation, the pressure in the suction chamber 3 drops at least to the ambient pressure.
In this pressure-load cycle, the seal ring 10 must on the one hand be sufficiently rigid to be able to withstand the high differential pressures acting, and on the other hand, be high on the short axis 6 in order to fulfill the sealing function. The contact must be made with a pressing force. Therefore, there is a risk of rapid wear or erosion of the seal ring into the short shaft 6 (Einschleifen), based on the relative stiffness required for the seal ring. Such damage is expected to occur particularly sharply if the short axis 6 does not rotate concentrically even slightly. Thus, generally speaking, the seal ring 10 is no longer dense after a short operating time of the screw compressor, and in particular also results in an unacceptably high oil leakage flow rate.

On the other hand, what is clear from FIG. 2 is that the bearing cover 8 (only the portion surrounding the short shaft 6 is shown)
The two seal rings 13 and 14 are shifted from each other in the axial direction.
Is arranged, and the oil chamber 15 is provided between these two seal rings. The cross section of the seal ring 13 on the rotary bearing portion side is substantially L-shaped,
The seal lip 16 on the side of the rotary bearing contacts the short shaft 6 under an intrinsic stress. The seal ring 13 is configured to reliably absorb a differential pressure generated between the suction chamber and the environment. By pre-filling the oil chamber 15 with oil, a lubricant film can be formed on the contact surface of the seal ring 13 on the short shaft 6, whereby wear of the seal ring 13 is significantly reduced, and the seal ring on the short shaft 6 is formed. 13 is prevented and the frictional resistance between the two is significantly reduced. The second sealing ring 14 on the other side has a sealing lip 17 corresponding to the sealing lip 16 of the sealing ring 13 and additionally extends substantially radially on the side opposite the oil chamber, also under inherent stress. And has a sealing edge 18 that contacts the short axis 6. The sealing lip 17 of the sealing ring 14 only has to withstand very little differential pressure. The additional sealing edge 18 also prevents dust and moisture from penetrating into the area between the sealing ring 14 and the short shaft 6 or even into the oil chamber 15. Thus, the seal ring 14 also withstands long operating times and has a very low risk of failure.

The oil chamber 15 is pre-filled with oil.
A standing pipe 19 protrudes from above the oil chamber. This riser pipe 19 opens radially into a suction conduit 20.
As described above, the suction conduit 20 opens into the suction chamber 3 of the screw compressor (not shown). The opening of the riser pipe 19 to the suction conduit 20 is located at a position provided higher than the oil chamber 15.

In the oil chamber 15, there is almost an ambient pressure in all operating and stopped states of the screw compressor. As already mentioned, no overpressure is applied to the sufficiently lubricated seal ring 13. Even if the oil chamber 1 passes through the seal ring 13 from the suction chamber 3
If oil leaks into 5, the leaked oil is sent by riser pipe 19 to a suction conduit 20 and returned to the screw compressor through the suction conduit. Two seal rings 13, 14
Can thus be used under optimal conditions each time and can therefore be expected to function without interruption even during prolonged intermittent operation of the screw compressor, with the tedious maintenance and maintenance of these sealing rings. No assembly work occurs.

The oil chamber 15 is pre-filled with oil. Filling takes place via an oil filling port (not shown) with a closing screw. In a modification, instead of an oil filling port with a closing screw, an oil filling device (not shown) for the oil chamber 15 is provided in the area of the standpipe 19, which can be tightly closed. Is also good.

As a further variant of the invention, the sealing rings 13, 14 and the oil chamber 15 can be arranged directly in the partition 5 of the screw compressor instead of in the bearing cover 8.

[Brief description of the drawings]

FIG. 1 is a sectional view of an end portion on a suction chamber side of a conventional screw compressor.

FIG. 2 is an enlarged schematic view of a screw compressor according to the present invention, showing an important part of the present invention.

[Explanation of symbols]

1 and 2 screws, 3 suction chambers, 4 casings, 5 partition walls, 6 short shafts, 7, 12 rolling bearings, 8 bearing covers, 9 holes, 10 seal rings, 11 short shafts, 13, 14 seal rings, 1
5 oil chamber, 16, 17 seal lip, 18 seal rim, 19 standpipe, 20 suction conduit

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Marx Echinger Germany Unterschleissheim Adalbert Stifterstraße 13 (72) Inventor Bernhard Schetsle Munchen Perkofenstraße, Germany 72 (72) Inventor Frank Meyer Germany München Schoenstrasse 39 (72) Inventor Robert Frank Germany Germerling Kell Schensteinerstrasse 102

Claims (6)

[Claims] 1. A screw compressor comprising at least one screw compressor.
Screws are provided, and this screw (1)
Ends on the suction side with a short axis (6) penetrating the bulkhead (5) from the suction chamber to the surroundings of the environment, and this short axis (6)
However, there is a type in which a rotary bearing is provided on a screw side, and a sealing member for a partition (5) is provided on an environment surrounding side so as to be shifted from each other in an axial direction. It has two axially guided sealing rings (13, 14), which contact the short axis (6) below, between which oil prefilled oil A chamber (15) is provided, and a standing pipe (19) is provided from the oil chamber (15).
A screw which leads to a suction conduit (20) connected to a suction chamber (3) of the screw compressor and opens at a higher point in the suction conduit than an oil chamber (15). Compressor. 2. A seal ring (13) on a rotary bearing portion side.
Is in contact with the short axis (6) under elastic intrinsic stress.
A sealing lip (16) having a U-shape, the other sealing ring (14) having a sealing lip (17) having substantially the same function, and additionally, on the opposite side from the oil chamber, also under inherent stress. Screw compressor according to claim 1, characterized in that it comprises a substantially radially extending sealing rim (18) for contacting the short axis (6). 3. The bearing cover (8) surrounding a short axis (6), which can be tightly flanged to the partition (5) on the environment side, in a sealing manner. 2. The screw compressor according to 2. 4. The screw compressor according to claim 1, wherein the oil chamber is connected to a closable oil filling port for pre-filling. 5. The screw compressor according to claim 4, wherein the oil filling port is located in a riser pipe (19). 6. The oil chamber according to claim 6, wherein the oil filling port is an oil chamber.
The screw compressor according to claim 4, wherein the screw compressor is located above the screw compressor.