FR2570445A1 - Bladed wheel centrifugal fan with motor outside the conveyed fluid, the intake and delivery ports of which lie on one longitudinal axis - Google Patents

Abstract

The invention relates to fans of the bladed wheel centrifugal type capable of conveying all gaseous fluids other than the ambient air itself (combustion gases up to 250 DEG C, corrosive gases, particle-laden air), the intake and delivery ports of which would lie on one rectilinear axis. Such a fan comprises a casing 10 with intake port 11 and delivery port 12 in line. A cage 14 containing a bladed centrifugal wheel 15 is incorporated into the casing 10. The bladed wheel 15 is connected to an external electric motor 17. In the case of hot gases a spiral 16 inserted between the motor 17 and the side wall 18 dissipates the heat. The invention can be fitted to a pipeline for conveying gaseous fluids without modifying the rectilinear layout thereof, thereby achieving savings in charge losses and great ease of assembly.

Description

 The present invention relates to a type of centrifugal fan, made up, like all known centrifugal fans, either of multiple-action impeller or reaction impeller, or of radial impeller, but the flow of the fluid carried (ambient clean air, gas combustion heat up to approximately 2500 C., various vapors, air charged with solid particles or pulverulent materials, etc.) is rectilinear, due to a particular arrangement of the suction and discharge orifices which are are placed on the same longitudinal axis.

 In known arrangements, centrifugal fans have their suction and discharge ports perpendicular to each other, requiring changes of direction in the layout of the fluid transport lines. Such devices complicate the manufacture of pipes, require more space and significantly increase the pressure losses in line.

 In addition, there are already centrifugal fans with rectilinear air flow, but the presence of motors or rotors in the transported fluid limits their use to clean ambient air whose temperature cannot exceed 60 C.

 According to a first variant, the present invention, relating to a centrifugal fan model whose suction and discharge orifices are in the same longitudinal axis avoids these drawbacks. It facilitates installation whenever it is necessary to interpose it on a pipe for transporting gaseous fluids, since it is quite obvious that the manufacture of straight sections is easier and, therefore, more economical than that comprising direction changes.

 In this case where it is a question of improving the performance of an existing duct (for example flue gas exhaust stacks), the vacuum of which is insufficient due to a lack of section or height, it suffices to cut this duct to insert the centrifugal fan without having to make any costly transformation of existing connections.

 According to a second variant, the impeller of such a centrifugal fan is driven by an external electric motor, independent of the type of fluid conveyed. This arrangement thus allows the transport of air loaded with dust or pulverulent matter, hot gases from different combustions Up to 2500 C, corrosive gases, various vapors, etc.

The present invention may, in any case, be well understood with the aid of the additional description which follows and of the appended drawings, thus revealing the conventional embodiment of a centrifugal fan and the preferred embodiment of the invention.

The accompanying drawings include three plates
- Plate 1/3 concerns the classic embodiment of a centrifugal fan.

 - Plate 2/3 shows the preferred embodiment of a centrifugal fan according to the invention.

 - Plate 3/3 gives all details on the structure of the centrifugal fan according to the invention.

As regards first of all the conventional embodiment, the plate 1/3 shows that the suction orifice (1) of any centrifugal fan (2) is 900 with respect to the discharge orifice ( 3), that the suction opening (1) is circular while the delivery opening (3) is generally square or rectangular and that, in order to produce a duct conveying a gaseous fluid in the rectilinear axis XY, it is necessary to make changes of direction (4, 5 and 6) and make a transformation (7) to find a circular section equal to that of the suction (1)
The arrangement according to the invention makes it possible, by producing a centrifugal fan according to 2/3 board which has suction (8) and discharge (9r opposite ports on the same longitudinal axis), to favor the flow of the transported fluid and to simplify installation by removing the complicated path shown on board 1/3.

 The attached 3/3 plate is a sectional view of a fan which, according to the invention, is characterized in that the suction and return orifices are in line.

 As shown, a welded envelope (10) constituting the body of the fan is provided with two opposite cylindrical orifices: suction orifice (11) and discharge orifice (12) located in the same axis.

 In the casing (10) is incorporated a cage (14) intended to receive a wheel either with radial blades, or with multiple blades with action or reaction (15) coupled directly to an external electric drive motor (17) absolutely independent of the fluid conveyed. A heat dissipation propeller (16) can be interposed between the motor (17) and the flank (18) of the casing (10), in order to prevent the transmission of calories on the motor shaft (17) when the gaseous fluid carried is at a temperature above 600 C. (example, case of combustion gases).

 The gaseous fluid under vacuum enters the suction opening (11), crosses the channel (19) and passes into the opening (20) for communication with the cage (14), is sucked in by the impeller (15 ). The latter pushes it back into pressure in the channel (21) to be evacuated through the discharge orifice (12).

 Depending on the size of the diameters of connections to the fluid transport pipe, the suction (11) and discharge (12) orifices can be fixed by interlocking for small sections or by flanges (13) for large ones. sections.

 The device, object of the present invention, can be used in all cases of transport of gaseous fluids. The drive motor being independent of the fluid conveyed and the construction can be made of ordinary steel sheet, aluminum sheet or stainless steel sheet allowing all applications: clean ambient air, air loaded with dust or powdery materials, hot combustion gases, various vapors, corrosive gases, etc.

 As is obvious and as follows from the above, the invention is in no way limited to these applications any more than to this embodiment of its various parts.

 On the contrary, it embraces all variants, the invention allowing all applications of ventilation, extraction and dusting.

Claims (3)

 1 - Centrifugal fan with wheels, either with multiple blades with action or reaction, or with radial blades, driven by an electric motor, characterized in that the suction and discharge ports are on the same longitudinal axis.  2 - Centrifugal fan according to claim 1, characterized in that the means used to put the suction and discharge ports on the same longitudinal axis is a welded envelope.  3 - Centrifugal fan according to claim 1, characterized in that the electric motor for driving the wheel is outside the fluid conveyed.