RU2287720C2 - Spiral machine - Google Patents

Abstract

FIELD: compressor and pump engineering.

SUBSTANCE: spiral machine comprises housing, ports for sucking and delivering gas, unmovable spiral member that engages the movable spiral member moving with eccentricity with respect to the unmovable spiral member to form closed compression spaces, device for preventing rotation, eccentric shaft mounted on bearings, and fan for circulating cooling air. The blades of the fan wheel are mounted with a spaced relation to the unmovable base that is a cooling surface to cause air to flow over the surface of the unmovable base to generate vortices, air flow detachment, and decreasing thermal resistance on the cooling surface that is provided with roughness. The wheel of the fan is provided with autonomous drive.

EFFECT: enhanced reliability and prolonged service life.

1 cl, 5 dwg

Description

The invention relates to the field of compressor engineering, pump engineering and can be used in spiral machines, where it is necessary to solve the problem of reducing thermal loads of structural elements, improving energy characteristics.

This design allows to increase the cooling efficiency of compressible gas, structural elements, improve energy characteristics and overall dimensions, increase the reliability and durability of the spiral machine.

Known is an air cooling system for a single-rotor scroll compressor having movable and fixed scroll elements with finned bases, on the cooling side forming air channels between the fins with housing elements, to which cooling air enters through an air duct system consisting of a fan, a spiral chamber system and rationally located inlets and bends.

The cooling air drawn in by the fan through the inlet is pumped with constant capacity into the spiral chambers, where it is accelerated, and then through the inlets made in the housing, it is directed to the air channels between the ribs, passing through which it removes the heat load from the working elements of the scroll compressor and thus reduces the temperature of gas compression as a result of heat exchange of cooling air with finned bases of movable and fixed spiral elements (WO 9602761 A1, 02/01/1996, F 04 C 29/04).

In the known design, a method of heat transfer intensification is applied, which consists in using the developed heat transfer surface, optimal rib geometry, increasing cooling air speed, increasing flow turbulence, which is ensured by a rational arrangement of structural elements, optimal passage sizes. The disadvantages of the known technical solutions arise from the method of intensification of heat transfer:

- the development of the heat transfer surface, which leads to an increase in weight and size characteristics and, consequently, the cost of the compressor;

- complication of the design due to the implementation of air duct systems, which also leads to an increase in the cost of manufacturing a compressor;

- insufficient cooling efficiency (low heat transfer coefficient) in comparison with other methods of intensification;

- additional energy consumption for pumping air through the air duct and channels.

The closest analogue is a twin-rotor scroll compressor having rotational spirals moving in concert with finned bases on the cooling side, which serve as fan wheels, and ribs as blades.

During the rotation of the spirals, and consequently the wheel blades in the zones located near the axis of rotation, the cooling air pressure decreases compared to the inlet pressure, due to which a continuous stream of cooling air is supplied to the wheel blades. The air between the blades, during rotation, receives a rotational movement, during which the thermal resistance of the boundary layer decreases through its turbulization and thickness reduction, and thus reduces the gas compression temperature as a result of heat exchange of cooling air with the bases, and the fan wheels are turbulators. Under the influence of centrifugal forces, cooling air moves to the peripheral zone of the wheels and is released into the atmosphere (US 6179590 B1, 02/13/2001, F 01 C 1/04).

The known design uses a more efficient method of intensifying heat transfer compared to the previous one, which consists in destroying the boundary layer and lowering the thermal resistance at the boundary of heat-exchanging media, however, such a design of the compressor does not allow to obtain a high heat transfer coefficient at the border of heat-exchanging media due to insufficiently high turbulization, which is primarily due to the rotation of the heat exchange surface along with the blades.

The technical task is to increase the cooling efficiency of compressible gas, structural elements and, as a result, increase the energy characteristics, reliability and durability of the spiral machine, improve overall dimensions.

The technical result is achieved by the fact that in a spiral machine comprising a housing, openings for suction and injection of gas, a stationary spiral element meshed with a movable spiral element that moves with eccentricity relative to the stationary spiral element with the formation of closed compression cavities, an anti-rotation device, an eccentric shaft on bearings, a fan for circulating cooling air, according to the invention lined with respect to a fixed base, which is a cooling surface with a gap to ensure that when the wheel rotates, air moves along the surface of the fixed base with the formation of vortices, separation of the air flow, and a decrease in thermal resistance on the cooling surface, on which artificial roughness is applied, while the fan wheel is equipped with an autonomous driven.

In addition, with a two-sided arrangement of spiral elements, the design includes two fan wheels.

The essence of the proposal is illustrated by drawings, where:

figure 1 presents a longitudinal section of a spiral machine;

figure 2 is a section aa in figure 1;

figure 3 is a section bB in figure 2;

figure 4 is a longitudinal section of a spiral machine with a two-sided arrangement of spiral elements.

figure 5 is a longitudinal section of a spiral machine with a two-sided arrangement of spiral elements with a cooling cavity.

The spiral machine shown in figure 1, contains a housing 1 with a suction hole 4, a stationary spiral element 5 with a discharge hole 7, which is in mesh with the movable spiral element 3.

The drive is carried out through the coupling half 13, the eccentric shaft 11 mounted on the bearing bearings 12 through the main bearing 10. For dynamic balance on the eccentric shaft, counterweights are pressed 14. To ensure the orbital movement of the movable spiral 3, an anti-rotation device 2 is installed in the case (in this design, a ball) .

The cooling system located in the housing includes a fan wheel 6, mounted relative to the cooling surface B with a clearance S. The blades of the fan wheel are made integral (or rigidly connected) with the drive pulley. The fan wheel 6 is equipped with an independent drive (not shown in the drawings).

The fan wheel 6 can also rotate around a fixed axis, rigidly connected to a fixed spiral 5. In this case, the drive of the fan wheel 6 is carried out through an intermediate roller 9 mounted in the housing 1 on its own rolling bearings using a belt drive 8 from the coupling half 13.

In the design of the spiral machine of FIG. 4, the movable spiral element 3 is made two-sided, the stationary spiral elements 5 are integral with the housing 1. The drive of the movable spiral element is carried out for one of the three leads 11 of the anti-rotation device 2, which performs the function of an eccentric shaft (in this design, the anti-rotation shaft device - leash). The cooling system includes two wheels of fan 6. The wheels are driven by an autonomous drive, but can also be carried out using a belt drive 8 for one of the two leads of the anti-rotation device 2 and the pulley system.

In the design of the spiral machine of FIG. 5, the movable spiral element 3 is also double-sided and consists of two spirals rotated 180 ° relative to each other and spaced apart by the size of the support bearing housing 12, rigidly connected by jumpers, cooling fins 16 and the support bearing housing 17 to form cooling cavities 15.

The drive is carried out through the coupling half 13, the eccentric shaft 11 mounted on the sliding support 12 through the main bearings 10. The cooling system includes two wheels of the fan 6, fixedly mounted on the shaft of the eccentric 11.

The spiral machine operates as follows. The gas medium is supplied to the suction 4 of the spiral machine during the orbital movement of the movable spiral element 3 relative to the stationary spiral element 5 with the eccentric "e" due to the presence of the eccentric shaft 11 on the bearings 12, counter-rotation device 2, preventing rotation of the spiral elements relative to each other, closed cavities are formed , the gas moves from the suction side 4 to the discharge side 7, compression occurs due to a decrease in the volume of the closed cavities. At the moment determined by the necessary parameters of the working process, the closed cavities are connected to each other and the discharge window and the compressible medium is forced out into the discharge window 7.

The suction cycle (opening and closing of external cavities) is performed in one revolution of the machine shaft. Then it repeats itself. The cycle of gas compression and ejection lasts longer, depending on the angle of twist of the spiral and the size of the discharge window.

When the gas is compressed, the temperature rises from the suction temperature to the discharge temperature, according to the laws of heat transfer, the heat extends to the elements of the spiral machine, including the working elements 3, 5, causing temperature deformations, to the bearings 10, 12, which themselves are sources of heat , and their performance is determined by a specific temperature regime, depending on the operating mode of the spiral machine. The thermal load from the elements of the spiral machine during operation is removed as follows.

From the moment the eccentric shaft rotates, the fan wheel begins to rotate. In the zone located near the axis of rotation of the wheel, the air pressure decreases compared to the inlet pressure, due to which a continuous stream of cooling air is supplied to the wheel blades. Under the action of centrifugal forces, the air moves to the peripheral zone of the wheels, cooling the heat exchange surface, which is the base surface of the fixed scroll element from the side of the fan wheel, and is released into the atmosphere.

When the fan wheel rotates, the base of the fixed spiral element is swept away by the blades, and powerful vortices are formed (Fig. 3), leading to flow separation at the base surface. Beyond the point of separation of the flow, the boundary layer is destroyed, its thermal resistance is significantly reduced, which increases the intensity of heat transfer at the border of heat transfer from the cooling air.

Such a constructive solution allows us not only to immediately use the high speeds of cooling air for cooling that we have in the fan wheel, and not to waste energy pumping it through the channels and air ducts, but also to use the fan (pump) wheel in parallel as a turbulizing device. The implementation of the movable spiral element with the formation of an additional cooling cavity 15 from the base (Fig.5) can further improve the cooling efficiency. In this case, cooling air from an autonomous fan enters the cooling cavity 15, where, moving along the cooling fins 16 of the spiral elements, the fin surface of the bearing housing 17 and the smooth surfaces of the bases of the movable spiral, removes the heat load from the elements of the spiral machine.

In the design of the spiral machine for cooling, a liquid coolant (using a pump) can be used, which allows to reduce the cooling area and thereby reduce the radial dimensions of the spiral machine.

Application on the cooling surface In artificial roughness leads to more efficient destruction of the boundary layer and increase the efficiency of heat transfer.

Thus, the proposed design of the spiral machine allows to increase the cooling efficiency of the elements of the spiral machine, to increase reliability and durability by using a more efficient cooling method, which consists in the formation of powerful vortices on the heat transfer surface, leading to the destruction of the boundary layer and an increase in the heat transfer coefficient at rather low costs ( no energy is wasted on pumping the coolant through channels, air ducts, etc.), while increasing the heat transfer coefficient It is approximately an order of magnitude compared with the cooling of finned air with cold air.

Claims (2)

1. A spiral machine comprising a housing, openings for suction and injection of gas, a fixed scroll element meshed with a movable scroll element that moves with an eccentricity relative to the fixed scroll element with the formation of closed compression cavities, an anti-swivel device, an eccentric shaft on bearing bearings, a fan for circulating cooling air, characterized in that the blades of the fan wheel are mounted relative to the stationary ju, which is the cooling surface, with a gap to ensure that when the wheel rotates, air moves along the surface of the fixed base with the formation of vortices, air flow separation, and reduction of thermal resistance on the cooling surface, on which artificial roughness is applied, while the fan wheel is equipped with an independent drive. 2. The spiral machine according to claim 1, characterized in that in a two-sided arrangement of spiral elements, the structure includes two fan wheels.

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