RU2270934C1 - Gas-transfer oil-filled compressor set - Google Patents

Abstract

FIELD: mechanical engineering; compressors.

SUBSTANCE: invention relates to gas-transfer sets of mainlines. According to invention, driven screw of compressor is arranged in screw chamber of rotor of electric motor of double squirrel-cage type. Oil tank for receiving atmospheric air communicates with suction chamber of compressor. Oil tank for receiving compressed air communicates with delivery chamber of compressor and in its space, higher than driven screw, inclined gauze of oil separator with baffle fitted under gauze is installed. Vent channels in form of pipes are made in lower part of both tanks, and tanks proper communicate through two bypass lines provided with shutoff valves.

EFFECT: increased efficiency of compressor up to 85%, increased its service life and repairability.

5 cl, 5 dwg

Description

The invention relates to the field of compressor engineering, in particular to gas pumping units of trunk pipelines.

A known compressor unit containing a drive motor with a stator and a rotor, a central screw made hollow, the stator of the electric motor is placed in its cavity along the axis, and the rotor is in the screw body [1].

A known compressor unit containing a housing with interacting rotors placed in it, at the end of the shaft of each of which is fixed a piston located in the discharge chamber of the housing, and an oil pump, moreover, a groove is made in the spool of the capacity regulator connected to the over-piston cavity of the discharge chamber and connected to the oil pump [ 2]. Both of these units do not provide sufficient reliability during the operation of the lubrication system.

The closest technical solution known to the proposed compressor unit is a gas-pumping oil-filled compressor unit containing a compressor with an engine, a working cavity in communication with the suction and discharge chambers, and an oil system [3].

In the known unit, when the compressor is operating, considerable forces arise that cause the destruction of bearings and other defects, such as an overestimated amount of oil in the tanks for lubrication and cooling.

The technical task of the claimed invention is to remedy these shortcomings.

This is achieved in a gas-pumping oil-filled compressor unit containing a compressor with an engine, a working cavity in communication with a suction and discharge chambers, an oil system and at least two drive screws mounted on bearing bearings, interacting with a driven screw rigidly fixed along the screw axis a chamber made in the cavity of a squirrel-cage rotor of the double “squirrel cage” type of the aforementioned engine, the oil tank for receiving atmospheric air being connected to the suction it has a compressor chamber and has a throat for filling oil and an air filter, an oil tank for receiving compressed air having a pressure reducing valve and pressure gauge is also in communication with the compressor’s discharge chamber, and an inclined oil separator grid with a baffle installed underneath is located in its volume above the driven screw ventilation channels in the form of pipes are made in the lower part of both tanks, and the tanks themselves are communicated with each other by two bypass lines with shutoff valves placed on them.

In addition, the compressor is made up of three sections: the first section (right half shaft) - a “working fluid” supercharger, the second section (electric motor rotor) - a locking mechanism between the first and third sections, the third section (left half-shaft) - to form a “working fluid” to the given parameters.

Leading and driven screws are multi-starting in the form of a cylinder or in the form of a truncated cone and face their vertices in opposite directions.

To reduce noise, the screws are reinforced with a polymer material, such as polystyrene.

Complete purification of air from oil and water vapors is carried out in the upper part of the oil tank, in communication with the discharge chamber, and two receivers installed horizontally with the formation of the frame base or separately from each other and having a connector along the center line with a filter element placed in it.

Figure 1 shows a diagram of a gas pumping oil-filled compressor unit; figure 2 - 5 - options for the location of the slave and drive screws of the compressor.

The unit contains a compressor 1 with an engine 2, a working cavity 3, in communication with a suction and discharge chambers 4 and 5 (respectively, left and right), an oil system and at least two drive screws 6 mounted on bearing bearings 7, interacting with the driven a screw 8, rigidly fixed along the axis of the screw chamber 9, made in the cavity of the squirrel-cage rotor 10 of the type of double "squirrel cage" of the mentioned engine 2, and the oil tank 11 for receiving atmospheric air is in communication with the suction chamber 4 of the compressor 1 and has a neck 12 for filling oil and an air filter 13. An oil tank 14 for receiving compressed air having a pressure reducing valve 15 and a pressure gauge 16 is also connected to the discharge chamber 5 of the compressor 1.

In the volume of the oil tank 14 above the driven screw 8 there is an inclined grid of the oil separator 16 with a baffle installed under it (not shown in the drawing), moreover, ventilation ducts are made in the form of pipes 17 in the lower part of both tanks 11 and 14, and the tanks 11 and 14 are communicated each other with two bypass lines 18 with stop valves 19 placed on them.

The compressor 1 is made of three sections: the first section 20 (right half shaft) (see figure 1), the second section 21 (rotor of the electric motor), the third section 22 (left half shaft) (see figure 1).

In addition, there are two receivers (not shown in FIG.) Mounted horizontally to form a frame base 23.

The air in the receiver is discharged through the pipe 24, and at the outlet of the working cavity 3 in the oil tank 14 is installed a check valve 25.

The unit operates as follows.

Gas enters the compressor 1 through the suction pipe of the suction chamber 4, is compressed together with the oil between the teeth of the screws 6 and 8, which form a screw chamber 9 with the walls of the rotor 10. When the screws 6, 8 are rotated, the volume of the chamber 9 increases and the suction process takes place. When the volume of the chamber 9 reaches its maximum, the suction process ends and the chamber is isolated by the walls of the rotor 10 and the covers from the suction and discharge chambers 4 and 5.

With further rotation, a mating protrusion of the driving screw 6 begins to penetrate into the cavity of the driven screw 8. The introduction begins at the front end and gradually extends to the discharge window 26 of the discharge chamber 5. From a certain point in time, both screw surfaces are combined into a common cavity, the volume of which is continuously reduced due to the translational moving the contact line of the mating elements in the direction of the discharge window 26. Further rotation of the screws 6, 8 leads to the displacement of gas from the cavity and into the discharge chamber 5.

At the initial moment of time, air with oil (mixture) is supplied to the working cavity by a supercharger 27 (a special device having eccentric cavities) rotating together with the rotor 10.

Further, when the unit enters the operating mode, the injection principle also applies, the speed and volume of the air-oil flow passing through the supercharger 27 increase significantly and are somewhat redundant.

Compressor 1 is made up of three sections.

Each section can work independently. But this is a single unit and a structurally formed machine with high technical and economic indicators.

The first section 20 (right half shaft) acts as a supercharger of the "working fluid" (air with oil) to the necessary preliminary operating parameters.

The second section 21 (rotor 10 of the electric motor 2) acts as a locking mechanism for the "working fluid" between the first and third sections, i.e. overflow of the "working fluid" from the third to the first section is excluded.

The third section 22 (left half shaft) forms a "working fluid" to the specified parameters.

The design of the central screw 8 (driven) does not depend on the number of driving screws 6. The driven (central) screw 8 is made of two or three parts. When the compressor is running, the driving screws 6 run around the driven 8. The driven 8 (central) does not rotate, i.e. stalled. Screws 6, 8 are multi-starting.

This compressor design is completely exempt from "parasitic" loads and has a significantly low metal consumption.

The separation of the working cavity 3 into three sections allows the lead screws 6 to be made both cylindrical and in the form of a truncated cone with a small angle to the base.

Screws in the shape of a truncated cone more resistant to axial and radial forces and easier in the assembly process and, no less important, allow the manufacture of screws with a relatively small diameter. The tops of the driving screws 6 and the top of the driven screw 8 are opposite.

The most suitable truncated cone screws for small and high power machines.

The operation of the "classic" compressor is based on forcing a certain amount of air with oil (at a time interval) in the contact zone of the driven 8 and the leading 6 screws and the housing.

This zone ultimately represents a limited plane (work surface). When three or more screws are installed, the number of limited planes increases. Therefore, the total working surface will be equal to the sum of the surfaces of the contact pairs (driven - lead screw). At the same time, if air leakage in the first section is inevitable, then it is absolutely excluded from the third.

These and other changes allow the compressor to be executed in small overall dimensions. A sharp decrease in metal consumption and a change in the cooling system exclude auxiliary equipment. The compressor control system is maintained.

Depending on operating conditions, power and purpose, motors with squirrel-cage or with a phase rotor can be used. The role of the engine side covers (bearing shields) is performed by the walls of the right and left tanks. This can significantly improve the thermal regime. The rotor is protected from contact (for safety reasons) by a casing on the two end faces of the motor housing.

When installing (operating) the compressor in a gas and dust hazardous environment, the walls of the right and left tanks are slightly different (spark, explosion-proof design).

In production, where a metered volume of air is required at any given time, it is necessary to use a direct current motor or an engine with a phase rotor. Compressors made on the basis of clearly pole motors are cheaper in the manufacture of similarly obviously not pole motors (applies to large-sized machines).

Electric motors are made with a special design rotor without increasing the cost. With a change in rotor design, cooling changes. The air flow is replaced by an air-oil (40% / 60%) flow passing through the screw chamber, and cooling is more intense.

The rotor 10 of the engine 2 simultaneously performs the functions of the housing of the screw chamber 9 of a single-screw compressor or section when installing several screws.

The cavity where the screws are installed, including the central one, are connected to the rotor in a single common unit and have one peripheral speed.

The rotor 10 of the engine 2 is made with a double "squirrel cage" with squirrel-cage rings. Such an engine is more expensive in cost, but more durable and has better starting characteristics.

Starting the electric motor is somewhat difficult (for which a double squirrel cage motor is adopted). After reaching the operating mode, the rotor 10 is affected by the total torque (EMF of the electric motor + kinetic energy, etc.).

Depending on the design (geometry) of the screw (s), the machine can operate as a compressor or a high-pressure pump. When performing a reversible machine, the right and left half-shafts are the same in design.

When working as a pump, having more than three screws is not economically rational. This is determined by the viscosity of the material and temperature characteristics.

The compressor equipment in its composition has an air intake system combined with an oil tank, a discharge system with air purification from oil, also combined with an oil tank.

Oil or emulsion is used to seal, lubricate and cool the compressor. The volume of oil in each tank is determined by the power of the machine and the temperature characteristics of the oil.

The oil tank 11 with the air filter 13 is installed on the suction side. On the discharge side, a tank 14 is also installed, in which a grid is mounted above the central screw 8 to separate large drops of oil from the air stream.

Oil is poured into both tanks. Tanks 11 and 14 do not have direct communication with the atmosphere (through valves and air filters). The cooling of the oil occurs due to the natural circulation of air through the ventilation channels, made in the form of pipes 17 in the lower part of the tanks 11 and 14.

Partial separation of the liquid phase of the oil occurs due to a sharp rotation of the flow of the air-oil mixture with a chipper directed downward and collision with a mesh stretched at an angle above the chipper.

Partial separation from the air flows down. For the flow of oil into the right oil tank 11, two bypass lines 18 are made of pipes of the calculated diameter. When inoperative, the oil level in both tanks is the same (communicating vessels). During operation, pressure is created in the left tank 14 and this allows oil to flow into the right tank 11 without a forced mechanism. The flow of oil is regulated by valves installed on the bypass lines, i.e. oil level is maintained automatically.

Complete air purification from oil and water vapor occurs in the right tank 11 and in 2 receivers. The receivers are installed horizontally (they perform the functions of the frame base 23 or are installed separately) and have a center line connector where the filter element is mounted (not shown in Fig.).

Air path: - partially purified air from oil and moisture from the left tank 14 enters the first receiver, accumulates in the upper part of the receiver and flows down to the second receiver, is completely cleaned of oil and moisture vapor - then to the consumer.

Relatively small mechanical loads on the screws allow the reinforcement of the screws with polymeric materials (polystyrene). This dramatically reduces noise during machine operation and increases maintainability (i.e., the possibility of cheap restoration of screws).

When the compressor is operating, significant forces arise that cause bearing failure and other defects.

In some cases, to remove these efforts, two bearings are placed next to each other - roller and angular contact, spring washers, springs, etc.

To remove loads from the bearings, a "hydraulic cushion" is installed (not shown in the diagram), which receives radial and axial loads. The "pillow" is charged with oil during manufacture. It accepts dynamic and static loads, constantly keeps the outer cage of the angular contact bearing (one) in the given parameters. The thrust bearing on the other side of the screw is a ball, lighter series.

The main operation of the "hydraulic pads" occurs at the time the compressor starts, then the pressure (oil compression) is equalized and depends only on the oil temperature. The higher the oil temperature, the stiffer the pillows are and the screw is constantly in a fixed (calculated) position. The "working surface" retains its area for a long time. This in turn allows you to stabilize the oil temperature and the volume (capacity and pressure) of air.

Information sources

1. SU 641159 A, IPC 7 F 04 C 23/02, op. 1979.

2. SU 1679059 A1, IPC 7 F 04 C 29/02, op. 1991.

3. SU 1719720 A1, IPC 7 F 04 D 25/00, 1992.

Claims (5)

1. A gas pumping oil-filled compressor unit comprising a compressor with an engine, a working cavity in communication with a suction and discharge chambers, an oil system and at least two driving screws mounted on bearing bearings, interacting with a driven screw rigidly mounted along the axis of the screw chamber made in the cavity of the squirrel-cage rotor of the double “squirrel cage” type of the aforementioned engine, the oil tank for receiving atmospheric air in communication with the suction chamber of the comp It has an oil filler neck and an air filter. An oil tank for receiving compressed air is also connected to the compressor’s discharge chamber. It has a pressure reducing valve and a pressure gauge, and an inclined oil separator with a baffle installed underneath is located above the driven screw. parts of both tanks have ventilation ducts in the form of pipes, and the tanks themselves are communicated with each other by two bypass lines with shutoff valves placed on them. 2. The compressor unit according to claim 1, characterized in that the compressor is made of three sections: the first section (right half shaft) is a “working fluid” supercharger, the second section (electric motor rotor) is a locking mechanism between the first and third sections, the third section ( left half shaft) - for the formation of the "working fluid" to the specified parameters. 3. The compressor unit according to claim 1, characterized in that the lead and driven screws are multi-start in the form of a cylinder or in the form of a truncated cone and face their vertices in opposite directions. 4. The compressor unit according to claim 1, characterized in that to reduce noise, the screws are reinforced with a polymeric material, for example polystyrene. 5. The compressor unit according to claim 1, characterized in that the air is completely cleaned of oil and water vapor in the upper part of the oil tank in communication with the discharge chamber, and two receivers installed horizontally to form a frame base or separately from each other and having an axial connector with a filter element located therein.

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