RU2413877C1 - Double-sided suction radial-flow flue-gas pump - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: flue-gas pump comprises volute casing, impeller with vanes arranged between main and cover conical disks, suction branch pipes, suction pockets and guide vanes. Width b₁ of impeller inlet makes 21-23% of impeller diametre D. Width b₂ of impeller outlet makes 11-13% of D. Radius R of intake section of impeller cover disk makes 4-6% of D. Volute casing opening A makes 50-70% of D. Size B of volute casing outlet section in the plane of impeller rotation makes 60-90% of D, where b₁ is the distance at the inlet from impeller main disk to impeller cover disk inlet plane, b₂ is the distance from impeller main disk to its cover disk along vane rear edge.

EFFECT: reduced capital and operating costs.

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Description

The invention relates to fan building, and in particular to the design of a double-suction centrifugal exhaust fan designed for transporting gases in gas cleaning systems with a capacity of Q from 200,000 to 450,000 m ³ / h with a developed full pressure Pv in the indicated capacity range at a temperature of the transported medium of 100 ° C from 9000 up to 7000 Pa.

Known centrifugal smoke exhauster double-sided suction GD-26 × 2, consisting of a impeller with a diameter of 2.6 m, chassis, spiral housing, suction nozzles, suction pockets and guide vanes, designed for recirculation of hot flue gases of stationary steam boilers. (Draft machines. Industry catalog. Part 1. Central Research Institute of Information and Technical and Economic Research in Heavy and Transport Engineering. Moscow, 1988, p.123-128).

The known smoke exhauster ensures the achievement of these parameters in terms of productivity and full pressure, however, the overall dimensions make it difficult to use in gas cleaning systems due to the significant associated capital costs for the construction of building structures.

Also known is a double-suction centrifugal exhaust fan DC-25 × 2, designed to aspirate flue gases from furnace units in the production of cement, which is the closest analogue of the invention. (Draft machines. Industry catalog. Part 1. Central Research Institute of Information and Technical and Economic Research in Heavy and Transport Engineering. Moscow, 1988, p.143-148).

The smoke exhaust consists of an impeller with a diameter of 2.5 m, a running gear, a spiral case, suction pipes, suction pockets and guide vanes.

The known smoke exhauster provides the required parameters for productivity and full pressure, however, its use leads to significant costs of electric power to the drive and additional loss of total pressure in the spiral casing and gas ducts of the gas treatment system. These shortcomings are caused by a significant 30-40% increase in the developed total pressure compared to the required value and high flow rates in the flow part and in the outlet section of the spiral exhaust case.

The objective of the invention is the creation of a smoke exhauster, providing the required values of productivity and full pressure, reducing power consumption while minimizing the cost of capital investment and operating costs.

The technical result consists in reducing the flow rate, optimizing the flow structure in the flow part and in the outlet of the spiral exhaust case of the exhaust fan, increasing the efficiency and reducing pressure losses in the gas ducts of the gas cleaning system by reducing the impeller diameter by increasing the impeller width, increasing the radius of curvature the input section of the covering disk of the impeller, increasing the disclosure and the size of the output section of the spiral casing while reducing material capacities and ease of installation.

The specified result is achieved by the fact that in a double-suction centrifugal smoke exhauster containing a spiral casing, an impeller consisting of blades located between the main and covering conical disks, suction pipes, suction pockets and guide vanes, the impeller width b ₁ at the inlet is 21- 23% of the impeller diameter D at the outlet edges of the blades, the inlet width b ₂ of the impeller is 11-13% of D, the radius R of the inlet portion of the impeller cover disk is 4-6% of D, disclosed the diameter A of the spiral casing is 50-70% of D, the size B of the outlet of the spiral casing in the plane of rotation of the impeller is 60-90% of D, where

b ₁ - the distance at the entrance from the main disk of the impeller to the plane of the inlet of the covering disk of the impeller,

b ₂ - the distance from the main disk of the impeller to the covering disk of the impeller along the outlet edge of the blade.

Figure 1 schematically shows a longitudinal section of the flow part of the exhaust fan, according to the invention,

figure 2 - section EE, figure 1,

figure 3 is a view of I in figure 1 on an enlarged scale,

figure 4 - aerodynamic characteristics of the exhaust fan, according to a utility model, obtained as a result of tests.

The exhaust fan (Fig. 1) consists of an impeller 1, a spiral housing 2, suction nozzles 3, suction pockets 4, guide vanes 5. The impeller 1 has a diameter D along the outlet edges of the blades and consists of a main 6 flat disk and 7 conical disks covering 7 . The blades are fixed between the main and the covering disks 8. The width b ₁ of the impeller at the inlet (the distance at the entrance from the main 6 of the disc to the plane of the inlet of the covering 7 of the disc) is 21-23% of the diameter D of the impeller, the width b ₂ of the impeller at the exit (the distance from the main 6 disk to the covering 7 disk along the output edge of the blade 8) is 11-13% of D, the radius R of the inlet portion of the covering disk of the impeller is 4-6% of D, the opening A of the spiral casing is 50-70% of D, size B spiral outlet Nogo housing in the plane of rotation of the impeller is 60-90% of D.

Dimensions b _{1 of the} width of the impeller 1 at the inlet, b _{2 of the} width of the impeller 1 at the outlet, radius R of the inlet portion of the covering disc 7 of the impeller 1, opening A and the size B of the outlet of the spiral housing 2 in the plane of rotation of the impeller provide speed reduction, optimization flow patterns in the flow part of the impeller and in the spiral casing of the smoke exhaust, reducing pressure losses in the flues of the gas cleaning system while reducing the diameter of the impeller by increasing the width of the impeller, increasing the input radius -stand portion covering the impeller disc, disclosing larger size and the outlet section of the spiral casing.

Smoke exhaust works as follows.

The gas flow enters through the guiding apparatus 5, the suction pockets 4 and the suction nozzles 3 at the entrance to the impeller 1, the width b ₁ at the inlet (the distance at the entrance from the main 6 disk to the plane of the inlet of the covering 7 disk) which is 21-23% of the diameter D of the impeller 1. The radius R of the input section of the covering disk of the impeller is 4-6% of the value D. In the impeller 1, energy is transferred to the flow. Leaving the impeller 1, the width b ₂ at the exit (the distance from the main 6 disk to the covering 7 disk along the output edge of the blade 8) which is 11-13% of D, the flow enters the spiral casing 2, in which there is a decrease in speed and conversion dynamic pressure into static. From the spiral casing 2, the flow is directed through the outlet into the gas duct of the gas treatment system. Opening A of the spiral casing is 50-70% of D, the size B of the outlet of the spiral casing in the plane of rotation of the impeller is 60-90% of D.

The regulation of productivity and full pressure of the exhaust fan is carried out by synchronous rotation of the blades of the guide vanes 5.

As a result of a decrease in the flow rate, optimization of the flow structure in the flow part and in the outlet of the spiral exhaust case, the pressure losses in the flow part and in the flues of the gas cleaning system are reduced while the impeller diameter is reduced due to the increase in the impeller width and the radius of the input section of the working impeller cover wheels, increasing the disclosure and size of the outlet of the spiral housing in the plane of rotation of the impeller.

The ability to achieve a technical result with the indicated parameters b ₁ , b ₂ , R, A, B is confirmed by the results of experimental studies conducted when testing models of a double-suction centrifugal smoke exhaust fan GD-26 × 2 with a impeller diameter of 2.6 m of a D-25 × centrifugal smoke exhaust fan 2 with an impeller diameter of 2.5 m and a double-acting centrifugal smoke exhaust according to the invention at the same rotational speed of 980 rpm.

Smoke exhausters according to the invention were manufactured with:

- diameter D of the impeller 2.2 m,

- b _{1 the} width of the impeller at the inlet 21, 22, 23% of D,

- b _{2 the} width of the impeller at the output of 11, 12, 13% of D,

- R with the radius of the input section of the covering disk of the impeller 4, 5, 6% of D,

- And the opening of the spiral case 50, 60, 70% of D,

- In the size of the output section of the spiral casing

in the plane of rotation of the impeller 60, 75, 90% of D.

As a result of the tests, a decrease in the flow rate, optimization of the flow structure in the flow part and in the outlet of the spiral exhaust case of the exhaust fan, reduction of pressure losses in the flow part and in the flues of the gas cleaning system, and an increase in the efficiency by an average of 5% were established.

Studies have shown that deviations from the selected values of b ₁ , b ₂ , R, A, B both in the direction of decreasing and increasing, significantly reduce the result.

The aerodynamic characteristic obtained as a result of the tests is presented in figure 4.

The invention provides improved performance with a reduced impeller diameter.

Claims (1)

Double-sided centrifugal exhaust fan containing a spiral housing, an impeller consisting of blades located between the main and the covering conical disks, suction nozzles, suction pockets and guide vanes, characterized in that the inlet width b ₁ of the impeller is 21-23% of the diameter D of the impeller, the width b ₂ of the impeller outlet is 11-13% of D, the radius R of the inlet portion covering the impeller drive is 4-6% of D, the disclosure of A spiral casing is 50-70% of D, again ep in the outlet section of the spiral body in the plane of rotation of the impeller is 60-90% of D, where b ₁ - distance from the main inlet to the impeller to drive the inlet plane of the impeller disk coating, b ₂ - distance from the impeller to the primary drive the covering disk of the impeller along the outlet edge of the blade.

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