Combined Fluid Impellers And Self-sealing Closures

Abstract

A combined fluid impeller and self-sealing closure has a plurality of blades mounted on the periphery of a rotor ring for pivotal movement about a radial axis. The blades are arranged so that they are in overlapping, sealing relationship with respect to one another when the impeller is at rest, and are in an open, impelling position when the impeller is rotating. The blades are opened by means of weights arranged in the rotor ring which are moved by centrifugal force when the impeller is rotating and rotates a control member arranged inside the rotor ring which in turn rotates the blades to their open position.

Description

This invention relates to a combined fluid impeller and self-sealing closure or louver-impeller, and of the type in which a plurality of blades are pivotally supported along the circumference of a rotor and adapted, when the rotor is at a standstill, by means of return spring means to be held in a closure position, in which their side edges are overlapping each other or arranged so close to each other that passage of air through the impeller is barred, and in which each blade is provided at its root with a pivot pin, pivotally connected to a rotor ring constituting a part of the rotor and attached to a supporting disc adapted to be firmly connected to the impeller shaft, and in which each blade is further connected to a control member adapted to adjust the angular position of the blades and connected to at least one rotating mass arranged in the rotor and adapted, when the rotor is rotating, due to the centrifugal forces resulting from the rotation of the rotor to activate the control member for pivoting the blades into their open position.

In most hitherto known louver-impellers the blades are pivoted at the one side edge and are, counteracted by return spring means, turned into their open position partly by the centrifugal forces acting on the blades and partly by the airflow developed by the impeller. The initial pivoting towards the open position at the time of staring the rotor, requires the effect of the centrifugal forces, wherefore in the known impellers of this type the pivot axis of the blades are arranged along a conical surface. This involves, however, a relatively long axial length of the impeller. Since, moreover, in these known louver-impellers the forces tending to maintain the blades in their open position are relatively low, only relatively weak return spring means can be used, involving, in connection with the relatively large surface areas exposed to blast directed towards the impeller when the same is in a closed position, rattling of the blades. Further such louver-impellers will only be effective when the rotor is rotating in one direction, whereas in many cases, for example in connection with impellers for cow-houses, stables, etc. it may be desirable that the impeller, through reversal of the direction of rotation, can be made blow in both directions.

Certainly, in the remote past, as will be apparent from the British Pat. Specification No. 629.339, a louver-impeller has been proposed of the type first above mentioned, which impeller affords the possibility of reversing the direction of flow through reversal of the direction of rotation of the impeller shaft. In this known impeller the rotating mass is constituted by weighted arms extending in the longitudinal direction of the rotor shaft and pivoting radially outwards during the rotation of the shaft counteracted by the return spring means, and thereby into the airflow developed by the impeller. Also a louver-impeller of this type has a considerable axial dimension, and further the weightened arms involve a not unessential reduction of the efficiency of the impeller.

The object of the present invention is to provide a louver-impeller of the type above first mentioned, which may be given a small axial dimension, and which ensures that the device for operating the blades will be without any influence on the efficiency of the impeller.

According to this invention this is attained thereby that the rotating mass or each of them eccentrically with respect to its axis of rotation is pivotally supported by the supporting disc for pivoting parallel therewith and is connected to the control member for operation thereof, and that the return spring means are connected to the rotating mass, urging this mass towards its position next to the axis of rotation of the rotor, in which position of the rotating mass the control member is maintained in its position corresponding to the closure position of the blades. Hereby a compact controlling device is obtained, which may be arranged within a hub of the same magnitude as hubs of impellers without adjustable blades.

The connection between the control member operated by the rotating mass and the blades may be provided in many different ways. Considering the controlling devices generally used in connection with impellers with adjustable blades, it may be obvious to use such a controlling device, in which each blade pivot pin is provided with a lateral arm engaging a control member, axially slidably and limited rotatably arranged around the rotor shaft, and which by means of connecting devices is axially displaced by the rotating mass. Such a cam device requires, however, a relatively great axial length, and involves relatively high frictional resistance that may reduce the sensitiveness of the device.

It is more expedient, therefore, that the impeller is of the type known per se, in which the pivot pin of each blade is provided, inside the rotor ring, with a lateral arm engaging the control member, which is arranged within the rotor, rotatably concentric to the axis of rotation of the rotor, in which case it has been found most appropriate that the rotating mass is provided with a lever, through which it is pivotally connected to the supporting disc, and which lever is provided with a lateral pin engaging an approximately radially extending slot or groove in the control member, whereby it is obtained that the controlling device requires only a quite small axial dimension and that minimum friction results.

Moreover, it may be advantageous that the return spring means comprises for each rotating mass a return spring inserted between the return spring, preferably the lever thereof, and the supporting disc, so that the return spring, instead of being directly connected to the control member, as has always been the case previously, is only indirectly acting thereon and whereby the most compact assembly of the members located within the hub may be obtained, at the same time as the frictional resistance that is of importance during the opening and closing movements of the blades is minimized, due to their not being affected at all by the return spring means.

These and various other objects and advantages are attained by the construction hereinafter described with reference to the accompanying drawing, wherein:

FIG. 1 is a fragmentary front view of a louver-propeller embodying the invention, and

FIG. 2 is a cross-sectional view taken on the line II-II in FIG. 1.

In the embodiment illustrated an impeller hub 52 is fastened to an impeller shaft 50. The hub 52 is provided with a radially extending supporting disc 54 provided at its periphery with a rotor ring 56 concentric to the shaft 50.

The impeller comprises eight blades 58, each provided at its root with a pivot pin 60 extending along the center axis of the blade and pivotably mounted in the rotor ring 56 and in a hub 62 provided at the inner side of this ring 56. The blades 58 are of such shapes that, when turned into a position, in which they extend approximately in a plane radial to the shaft 50, their side edges are overlapping to provide a tight closure.

Each pivot pin 60 is provided inside the hub 62 with a socket 64, provided with a forward extending lateral arm 66.

A control disc 68, in the drawing partly broken away, is rotatably arranged on the hub 52 and is for each arm 66 provided with an opening 67, through which the arm 66 extends. Owing thereto, the control disc 68 will, when turned counterclockwise, operate the arms 66 and thereby turn the blades 58 out of the joint plane, so that they can function as impeller blades. Subsequent reverse operation of the control disc 68 will make the blades revert to the closure position shown.

On the supporting disc 54 there is at each of two diametrally opposite points pivotably around a pivot pin 70 arranged an angle-shaped lever 72, carrying a weight 74 and thus constituting a rotating mass. Only one of these two rotating masses appears on the drawing. Each angle-shaped lever 72 is provided with a lateral pin 76 axially extending through or into an oblong aperture 78 in the control disc 68, for example a slot or a groove. Each angle-shaped lever 72 is provided, moreover, at the free end with a projection 80, and a compression spring 82, functioning as a return spring, is inserted between the projection 80 and the following hub 62. This spring 82 tends to turn the lever 72 into such a direction that the weight 74 is moved towards the hub 52 and still remains at a certain distance therefrom at any time.

When the impeller shaft 50 is brought to rotate, the centrifugal forces will move the weights 74 outwards, whereby the levers 72 turn around the pivot pins 70 involving the pins 76 engaging the control disc 68 to turn the latter in a counterclockwise direction, whereby the blades 58, as explained hereinbefore, are turned away from their closure position shown into a position, in which they can function as impeller blades and permit blast to pass through the impeller. The magnitude of the turning of the blades can be limited by the weights 74 contacting the rotor ring 56, but is is also possible, as shown, to provide the rotor ring 56 with adjustable stops 86 for the weights 74, whereby the turning movement of the blades, and, consequently, the output of the impeller can be restricted or adjusted.

When the impeller is stopped, the return springs 80 will turn the levers 72, and thereby the weights 74 and the blades 58 back into the initial position shown, whereby the air passage through the impeller is again barred. Since the weights 74 cannot engage the hub 52, the return springs 82 will tend to force the edges of the blades 58 into close intercontact.

84 indicates a protecting disc, which surrounds the hub 52 and attached to the supporting disc 54 serves as closure for the hollow space within the ring 56 encompassing the control device.

Since the weights 74 will be moved outwards by the centrifugal forces irrespective of the direction of rotation of the shaft 50, the impeller shown will be effective for both directions of rotation, the respective directions of flow being opposite, however.

It should be noted that in the case of the impeller shown has to be used for one direction of flow only, it will be expedient that the pivot pins 60 of the blades, instead of being located in the center axis of the blades, are displaced slightly rearwards in the direction of rotation in relation to the center axis, whereby the centrifugal effect on the blades, tending to turn the blades towards their closure position, is partly compensated by the effects of the airflow.

Claims

We claim:

1. A combined fluid impeller and self-sealing closure, comprising, in combination:

a. a rotor member having a supporting disc adapted to be firmly connected to an impeller shaft having an axis of rotation and a rotor ring defining a circumference and attached to said supporting disc;

b. a plurality of blades each having an inner end and pivotally supported along the circumference of said rotor ring and mounted to be pivoted about a radial axis between a closure position in which said blades act together to bar the passage of fluid through the impeller, and an open, fluid impelling position;

c. a centrally arranged pivot pin provided at the inner end of each of said blades, said pivot pin pivotally connected to said rotor ring and extending inside the same;

d. a control disc arranged inside said rotor ring and pivotal concentric to the axis of rotation of said rotor, said control disc defining an opening for each of said blades, and each of said pivot pins being provided with a lateral pin arranged inside said rotor ring and extending through a corresponding one of said openings in said control disc;

e. a rotating mass arranged within said rotor ring, said rotating mass comprising a lever and a fly-weight attached to one end of said lever, said fly-weight and said lever together forming an angle member opening away from the axis of rotation of the impeller shaft;

f. pivot means pivotally connecting said lever near its end opposite said fly-weight to said supporting disc for pivoting movement parallel to said supporting disc, said lever being provided between said pivot means and said fly-weight with a lateral control pin, said control disc being further provided with a substantially radially extending slot or groove, and said control pin engaging said slot or groove; and

g. return spring means interconnecting said rotating mass and said supporting disc for urging said rotating mass toward its position adjacent the impeller shaft, and for maintaining said control disc in its position corresponding to the closure position of said blades.

2. An impeller according to claim 1, wherein said rotor ring is provided for each of said blades with an inwardly projecting hub member for the corresponding one of said pivot pins, said lever having a projection extending outside said pivot means and in between two adjacent ones of said hub members, and wherein said return spring means is a compression spring inserted between said projection and one of the last said two adjacent hub members.