FR2501801A1 - AUB WHEEL AND TOOLS AND METHODS FOR MAKING THEM BY MOLDING - Google Patents

Abstract

A. BLADE WHEELS. B. IT INCLUDES A FLANGE 4 FORMING A HUB WHICH REVOLVES AROUND AN X, X AXIS AND FROM WHICH BLADES ARE BORN 1 HELICO-CENTRIFUGES ADMITTING THE X, X AXIS OF THE HUB AS AN AXIS OF REPETITION, THE IMAGINARY EXTENSION OF THE GENERATOR OF THE FLANGE 4 CUT THE HUB AXIS AND THE INTRADOS AND EXTRADOS OF THE BLADES 1 EXTEND OVER PORTIONS OF CYLINDER SURFACES WHOSE Y, Y AXES ARE INCLINED WITH RESPECT TO THE X, X OF THE HUB. C. PUMP.

Description

2501'801

  Impeller and tools and processes for them

manufacture By molding.

  The present invention relates to impellers and tools and methods for making them by molding. There are three types of paddle wheels: Those called radial centrifugal (or centripetal) for which the trajectories of the fluid particles are contained in perpendicular planes - the axis of rotation, except in the immediate vicinity of the latter; those called axial in which the fluid particles remain substantially at a constant distance from the axis of rotation; and those say

  helico-centrifugal (or helico-centripetal)

  between the two previous cases in the-

  which vanes are shaped in such a way that the fluid particles describe a path

  having both a radial component and a

  axial posing. It is this last type of wheels that

the invention improves.

  The alignment of the blades of these wheels is regulated -

  by hydraulic considerations, which define in particular the angle of entry, the exit angle, the

  length, height, leading edge and profile.

  Dawn yes results in a complicated left form.

  It is not demoldable. To create it in the foundry, we create sand cores by assembling sectors where we hold together by gluing and

- -. 2-501801-

  by ligating. These assemblies give a piece of

  foundry, which has many burrs, which

  requires subsequent deburring, the dimensions of which are neither precise nor reproducible and whose surface condition is very poor. When the blade curves are modest, a monoblock core is used and the core maker shocks the fins of the core box to remove them from the core during the preparation of the core. Not only do the cores no longer respond to the ribs fixed by the hydraulic engineer and

  different from each other ,. but still this difference

  The difference is not known to the hydraulic engineer, and varies from one dawn to the next of the same wheel in an unforeseen manner, which depends on a more or less abrupt movement of the smelter. The manufacturer of helical-centrifugal cubic wheels does not know the actual profile of the vanes whose exact theoretical profile he has nevertheless determined and, because of this manufacturing uncertainty, he is led

  to take-larger margins of tolerance.

  The invention overcomes these drawbacks by a helicocentrifugal impeller whose surface state such as foundry or molding is impeccable, whose dimensions are accurate and can correspond exactly to the plans provided

  the smelter without the smelter encountering difficulties

  insurmountable culprits, and whose manufacture is more

  faster than in the past and can be automated.

  tExperience has shown that this paddle wheel had

  at least the same performance as the helicopter wheels.

  classic centrifuges and 'remember' performances

higher than these.

  The subject of the invention is a paddle wheel,

  comprising a hub flange which is

  evolution around an axis and from which are born helico-centrifugal blades admitting the axis of the hub as a repetition axis, characterized in that the imaginary extension of the generatrix of the flange intersects the axis of the hub and the intrados and extrados blades extend over portions of roll surfaces whose axes are inclined relative to that of the

hub.

  Preferably, the section of the cylinders

  is a circle and the flange is substantially truncated

  conical. The invention also relates to a core boot which comprises helical-centrifugal blades, with a repetition axis, the intrados and the extrados of each blade

  extending respectively over portions of

  cylinder face whose axes of revolution are

  inclined compared to that of repetition.

  The method of molding metal impeller wheels according to the invention consists in creating

  a core of sand in which are formed

  in the form of the vanes of the molding wheel, to fill these cavities with liquid metal, to allow the metal to solidify in one piece and to destroy the

  sand core to free the room, and is

  it consists in filling the core box according to the invention with sand, hardening the sand in a core and demolding the core of the box by pulling the blades of the box out of the core by printing them a next translational motion

their axis of revolution.

  In the accompanying drawings, given solely by way of example:

  Figure 1 is a partial view in

  perspective of a paddle wheel according to the invention.

2501O IQ

  FIG. 2 is a sectional view of a mold

to mold the wheel of Figure 1.

  FIG. 3 is an exploded view, with

  partially redeveloped, a core box for obtaining the core implemented in the mold of Figure 2; and FIG. 4 is a sectional view of a dawn

of the core box.

  The wheel of FIG. 1 comprises six helico-centrifugal blades 1 (only one of which is shown),

  of which the intrados 2 and the extrados 3 extend respectively

  on portions of roll surfaces,

  of circular section, whose Y, Y 'axes are

  clinched with respect to the axis X, X 'of repetition of the blades 1. The wheel comprises a flange 4 of revolution about the axis X, X'. The flange is substantially

  truncated. The blades 1 start from the flange 4.

  The wheel is made, in the foundry, using two frames 9, 10 lower and upper filled with sand, matching the outer forms of the wheel and, between the two frames, a core 8 of sand

  reproducing the inner shape of the wheel. (fi-

  gure 2) - after the casting and cooling of the metal, the sand is destroyed and the rough wheel is obtained

foundry.

  For the realization of the two chassis and the core, it is necessary to have: - two model plates reproducing the front face and the rear face of the wheel; a core box (FIG. 3) for carrying out

of the nucleus.

  The model plates are obtained at

  classic way without difficulty.

  The core box is essentially composed of a box bottom 11, a set of blades 12 and and a cap 13. Each blade 12 has a lower surface and

  an extrados which extend over portions of

  faces of a cylinder whose axis is inclined by

port to that X, X "of the bottom 11.

  It should be added to the dawn cleanly

  called a part called step 14 (Figure 4).

  This "footing" is embedded in the bottom 11

  box like a tenon in a mortise and allow-

  bet the setting up and the dismountability of the dawn 12 on the bottom 11 of box. Each blade 12 is removed from the sand core by a translation movement

  along the axis of the cylinder on which the blade extends.

  The core box makes it possible to manufacture as many cores 11 in sand as one wants to manufacture paddle wheels. Each core 11 is placed between the two frames 9, 10. Pouring metal. We release the

casting wheel by removing the sand.

Claims (5)

Patent claims   1. Impeller, comprising a flange (4), forming a hub) which is of revolution about an axis   (X, X ') and from which are born blades (1) helically   centrifugal motors which admit the axis (X, X ') of the hub as   repetition axis, characterized in that the prolongation   Imagination of the generator of the flange (4) intersects the axis of the hub and the intrados and extrados of the vanes (1) extend over portions of surfaces of   cylinders whose axes (Y, Y ') are inclined by port to that (X, XI) of the hub.   Wheel according to claim 1, characterized   risen in that the cross-section of the cylinders is a circle.   3. Wheel according to claim 1 or 2, characterized in that the flange is substantially frustoconical. 4. Core box, useful for manufacturing   of helical-centrifugal impellers according to the   1, 2 or 3, characterized in that it comprises   takes helical-centrifugal vanes with repetition axis   tion, the intrados and the extrados of each dawn   respectively on portions of roll surfaces whose axes of revolution are inclined   compared to that of repetition.   5. Method of molding a paddle wheel   helical-centrifugal metal according to the   1, 2 or 3, which consists in creating a sand core in which cavities are formed in the shape of the vanes of the molding wheel, filling these cavities with liquid metal, allowing the metal to solidify in   a piece and destroy the sand core for li-   bérer the coin, characterized in that it consists in creating a kernel box according to claim 4, to fill the sand core box, to harden the sand in a core and to unmold the core of the box out the the blades of the box out of the nucleus by printing them a translation movement following their axis of revolution.