SU1076641A1 - Auger centrifugal pump - Google Patents

Abstract

1. W a non-centrifugal pump comprising a housing with an inlet nozzle, a centrifugal wheel housed in the housing and an upstream screw with blades, the inner surface of the inlet nozzle having cylindrical sections of different diameters and a transitional conical section forming a sharp edge with a cylindrical section of a smaller diameter, forming a sharp edge the fact that, in order to improve the anti-cavitational qualities and to prevent low-frequency oscillations in a wide range of flow rates, the internal surface of the input atrubka has a second cylindrical portion to the centrifugal wheel and additional conical portion conjugated with the latter and the cylindrical portion of larger diameter at an acute angle in the flow direction. 2. A pump according to claim 1, characterized in that the interface line of additional conical and cylindrical sections is located at a distance from the input edges of the auger blades, determined from the expression (L CZ HD-6in | where D is the internal diameter of the input nozzle, In the angle of installation of the blade of the screw at the entrance, L - the number of blades of the screw. About 1 About O5 4 ;;

Description

11 The invention relates to suction and improvement of Schrott-centrifugal pumps. Known screw-centrifugal pump, comprising a housing with an inlet nozzle, a centrifugal wheel housed in the housing, and an auger with a bandage and vanes, and the inner surface of the inlet nozzle has -... -... Closest to the proposed technical entity is a screw centrifugal pump, comprising a housing with an inlet, a centrifugal wheel housed in the housing, and a prefixed auger with blades, the inner surface of the inlet pyotrub has cylindrical sections of different diameters and a transitional conical section forming a cylindrical a plot of smaller diameter acute edge1 at T2. The disadvantages of this pump are low anticavitational qualities and the danger of low frequency oscillations in a wide range of costs. The aim of the invention is the improvement of anti-vitality and prevention. the occurrence of low-frequency oscillations in the shorter-flow range. This goal is achieved by the fact that the screw-centrifugal pump containing. a housing with an inlet nozzle, a centrifugal wheel placed in the housing and a front-mounted auger with blades, the inner surface of the inlet tube has cylindrical sections of different diameters and a transitional conical section forming an additional edge with a smaller diameter cylindrical part, the inner surface of the inlet pipe has an additional cylindrical area in front of the centrifugal a wheel and an additional conical section mating with the last and cylindrical section of a larger diameter under the sharp angle in the direction of flow. In addition, the interface line of additional conical and cylindrical sections is located from the entrance edges of the auger blades at a distance determined from the expression

 P-0-5AG ft

,

u-d-s np

A 41 where D is the internal diameter of the inlet; And the angle of installation of the blade auger at the entrance; - the number of blades of the screw. FIG. 1 shows a preload screw centrifugal pump; FIG. 2 iipHBbie changes in the cavitation characteristics of pumps with different configurations -, -l- - -VJ, the inner surface of the inlet nozzle for values of 0.40 aPgxJn. loe 0.4-1.4; in fig. 3 is the same, for 10 of 0.30-0.46 and PBX / 10 0.2-1.2. The centrifugal pump contains a housing 1 with an inlet nozzle 2, a centrifugal wheel 3 placed in the housing 1 and a front screw 4 with blades 5, and the inner surface of the inlet nozzle 2 has cylindrical sections 6 and 7 of different diameters D and B- (.and transitional conical section 8, which forms a sharp edge 9 with a smaller diameter D-section Shyindrinsky section 6. The inner surface of the inlet 2 has an additional cylindrical section 10 in front of the centrifugal wheel 3 and an additional conical section 11 that is adjacent to after with a larger diameter section D at an acute angle about in the direction of flow. The mating line of additional conical 11 and cylindrical 10 segments is located from the input edges of the blades 5 of the screw 4 at the distance A, as determined from the expression IT.D-sin p where - B) the 1-morning diameter of the inlet nozzle, p) is the angle of installation of the auger blade at the inlet, 2 is the number of auger blades. The sharp edge 9 can be matched with the protrusion 12 of the cylindrical section 6 of smaller diameter) and pacni lies on the diameter c. The conical sections 8 and 11 and the cylindrical section 7 form an annular chamber formed at the inlet 2 and coaxial with the screw 4, an inlet. into which is located from the input edges of the auger blades at a distance

A screw-centrifugal pump works in the following way.

Wheels 3 with screw 4 formed in front of the latter, reverse currents by the surface of the conical section 11 deviate from the main flow direction. The chamber formed by the conical sections 8 and 11 and the cylindrical section 7 has a sufficient volume in order to effectively prevent the effects on the main flow under conditions with a high intensity of reverse currents. With the conical surface 8, the reverse currents return to the main flow and thus have some ejecting effect.

Comparative tests of screw-centrifugal pumps with various devices to improve anti-cavitation properties placed in

inlets, showed that the invention almost completely prevents the occurrence of low-frequency self-oscillations in a wide range of costs.

Experimental studies were carried out on a pump with the slits of the inlet nozzle: a usable section 7 width, 3D and diameter D "1.5 13, sharp edge 9 pa (laid on diameter d (O, 8-1.0) D, conical sections 8 and 11 are located to the direction of flow, respectively, at an angle of "40-60 ° and at an angle (and 20-30 °,

FIG. 2 and 3 curves correspond to the cavitation characteristics of various pumps; a is a wasp for you with a big mesh cone installed in front of the auger, b is for a pump with a bypass chamber, c is for the proposed pump, d is for a pump with a smooth inlet.

The application of the proposed pump provides an improvement in anti-cavitation qualities by 34% and an increase in pressure by 12% in the mode sd of 0.64 (Fig. 2). and in the USG mode, O) 3 9, respectively, by 60 and.3% (Fig. 3).

And

- CLUTCH

1 pg

W

1.2

YU

Claims (2)

1. SCREW CENTRIFUGAL PUMP, comprising a housing with an inlet pipe, a centrifugal wheel placed in the housing and an upstream auger with vanes, the inner surface of the inlet pipe having cylindrical sections of different diameters and a transitional conical section forming a sharp edge with a cylindrical section of a smaller diameter, characterized by that, in order to improve anti-cavitation qualities and prevent the occurrence of low-frequency oscillations in a wide range of flow rates, the inner surface of the inlet pipe has an additional cylindrical section in front of the centrifugal wheel and an additional conical section, conjugated with the last and cylindrical section of a larger diameter at an acute angle in the direction of flow. 2, Pump pop. 1, characterized in that the conjugation line of additional conical and cylindrical sections is located from the input edges of the screw blades at a distance, § determined from the expression where B is the inner diameter of the inlet pipe, '[3 - angle of installation of the screw blades at the inlet / Ί. - the number of auger blades. SU „„ 1076641 1 1076641