WO2019239306A1

WO2019239306A1 - Air shutter

Info

Publication number: WO2019239306A1
Application number: PCT/IB2019/054848
Authority: WO
Inventors: Edoardo Capello
Original assignee: Termotecnica Pericoli S.R.L.
Priority date: 2018-06-15
Filing date: 2019-06-11
Publication date: 2019-12-19

Abstract

A wall-mounted ventilation fan having an air-intake shutter with automatic opening by suction pressure, comprising a balanced mechanism formed by a first bar (11), which carries the vanes (111) referred to as "gravity" vanes that tend to close under the action of the force of gravity, and a second bar (12), which carries the vanes (112) referred to as "antigravity" vanes that open or close in the opposite direction with respect to the gravity vanes and that tend to close under the action of elastic-return elements (16), the bars (11) and (12) being connected to the frame (1) via spring shackles (211) (212) so as to form two distinct articulated quadrilaterals, which have as fixed points the centres of rotation (311, 312) of the vanes (111, 112) and are connected together by an arm (13), which is fixed with respect to the bar (12) and carries a scotch yoke (14) provided with a cam -shaped part (14 A) with which it engages a pin (15) fixed with respect to the bar (11). During closing, the passage of pin (15) on the cam part (14 A) of the scotch yoke (14) bestows on the vanes (112), owing to the action of the springs (16), a closing advance (112') that prevents any sticking of the vanes (111, 112) together.

Description

AIR SHUTTER

DESCRIPTION

The subject of the present invention is a wall-mounted ventilation fan, used for example in industrial plants, poultry farms, livestock facilities, greenhouses and the like and in particular an air-intake shutter for said ventilation fan with suction-pressure automatic opening.

Currently available on the market are various types of ventilation fans with shutters of a traditional type, i.e. , with vanes that, once open, close as a result of the force of gravity that acts on each of them, as for example described in the Italian patent No. 1371682 filed in the name of the same holder of the present patent application.

The present invention regards, instead, an air shutter for ventilation fans comprising a series of vanes referred to as“gravity vanes”, which tend to close under the action of the force of gravity, and a series of vanes referred to as“antigravity vanes”, which open or close in the opposite direction with respect to the gravity vanes and tend to close under the action of elastic-return elements.

Both of the above vanes tend to open under the action of an airflow. The combination of an antigravity vane and a gravity vane thus gives rise to a balanced mechanism.

There already exist on the market air-intake shutters of the type described above. However, in all these systems according to the prior art, the connection between the various vanes and the operating means implies the use of mechanisms (typically a series of gears) that constrain the relative position between a gravity vane and the corresponding antigravity vane.

Consequently, constituting the main characteristic of the present invention is a mechanism of connection between the various vanes with the use of two connecting rods, one for connecting together the gravity vanes and the other for connecting together the antigravity vanes, the two rods being in turn connected together by means of a connection element provided with a shaped scotch yoke.

Thanks to the particular shape of the above scotch yoke, there is offered the possibility of decoupling the position of the antigravity vanes from that of the gravity vanes so as to advance slightly closing of the antigravity vane with respect to the gravity vane in order to prevent any possible sticking of the vanes during closing.

The gravity vanes are pivoted to the frame and connected at the two ends by levers, which are in turn connected to a connecting rod referred to as“gravity-vane control rod”. Likewise, also the antigravity vanes are connected at the two ends by levers that in turn are connected to a connecting rod referred to as“antigravity-vane control rod”.

In particular, the two control rods are the connecting rods of two distinct articulated quadrilaterals, which have as fixed points the centres of rotation of the gravity and antigravity vanes, respectively.

Further aims, characteristics, and advantages of the present invention will emerge more clearly from the ensuing description, provided with reference to the attached drawings, wherein:

Figure 1 is a sectioned view in side elevation of a forced-aeration window of a wall-mounted ventilation fan according to the invention, provided with oscillating-vane louvre shutter, where the shutter is formed by two series of vanes connected together by means of two rods, with the vanes represented in the closed position (0°);

Figure 2 is a view similar to that of Figure 1 , with the vanes of the shutter in the position of maximum opening at an angle of 90°;

Figure 3 is a view similar to that of Figure 1 , with the vanes in a position of half- opening at an angle of 45°;

Figure 4 is a view similar to that of Figure 1 , with the vanes in a position of partial opening at an angle of 22°;

Figure 5 is a view similar to that of Figure 1 , with the vanes in a position of partial opening at an angle of 11 °;

Figures 6A, 6B, and 6C illustrate a detail on an enlarged scale of Figures 1 , 2, and 3, respectively, and highlight the means of synchronisation of opening/closing of the vanes; and

Figures 7 A and 7B illustrate a detail on an enlarged scale of Figures 4 and 5, respectively, and highlight the cam means that prevent sticking between the vanes in the angular positions represented on account of an advance in closing bestowed on the antigravity vanes.

With reference to the drawings and with particular reference to Figure 1 , designated by 1 is the protection guard of a wall-mounted ventilation fan, comprising the blower mouth 2. Designated by 3 is a fan carrying a pulley 4 aligned thereto, pivoted via the pin 5 to the internal wall 6. The fan 3 is driven in rotation by the electric motor 7, fitted on the shaft 8 of which is the pulley 9, which drives, via a belt transmission 10, the pulley 4 that is fixed with respect to the fan 3. Indicated by the arrow F is the direction of the airflow caused by the ventilation fan, and designated as a whole by S is the air shutter of the ventilation fan.

Designated by 11 is the bar of the gravity vanes, and by 12 the bar of the antigravity vanes. Designated by 111 are the gravity vanes pivoted at their ends, via the pins 311 , to the structure 1 and to an end of the spring shackles 211 , which are pivoted at their other end, via the pins 411 , to the bar 11.

Likewise, the antigravity vanes 112 are pivoted at their ends, via the pins 312, to the structure 1 and to an end of the spring shackles 212, which are pivoted at their other end, via the pins 412, to the bar 12.

Branching off from the bar 12 is a short orthogonal arm 13, which terminates with a scotch yoke 14 provided, on the side, with a cam shape 14 A, with which the pin 15 engages, which extends at 90° from the bar 11 fixedly thereto.

Designated by 16 is an extension spring connected in tension, at one end, to the structure 1 and, at the other end, to the bar 12.

Operation of the device referred to will emerge clearly from the ensuing description.

With reference to Figure 1 , the shutter is illustrated in its resting position. The ventilation fan is in the inoperative condition, and the vanes are all in the closed position.

Figure 2 shows the position of maximum opening of the vanes 111 and 112, which are all set at 90°, in a position concordant with the airflow F generated by the fan 3, driven by the motor 7.

Figures 3, 4, and 5 illustrate the positions of inclination assumed by the vanes 111 and 112 when they are subjected to airflows of progressively decreasing intensity.

Represented distinctly and designated by 112’ in Figures 7A and 7B is the advance bestowed on the antigravity vanes 112 (shown dashed) during closing as a result of passage of the pin 15 onto the cam part 14 A of the scotch yoke 14.

The above closing advance of the antigravity vanes is made possible by the use of the return springs 16, which act on the control rod of the antigravity vanes and exert a force of return that counters the forces involved (weight and aerodynamic lift), accelerating the motion of the antigravity control rod and hence advancing closing of the corresponding vanes.

The above condition of offset of position between the gravity vanes and the antigravity vanes in practice occurs prevalently during closing, i.e. , when the airflow ceases, and the force of the return springs prevails over the force due to the aerodynamic lift that acts on the vanes.

During start-up in fact, the suction pressure that the ventilation fan develops comes to create an airflow that exerts an opening force on the vanes much higher than the force of the return spring, rendering the latter force negligible. During start- up, then, the two types of vanes open without any appreciable offset with respect to one another.

The advantages deriving from the use of the air shutter according to the invention can be summed up as follows:

1. Reduced risk of jamming due to dirt: especially a shutter with suction-pressure opening, given the modest opening force available (due solely to the lift of the vanes themselves), requires a good fluidity of the mechanisms to prevent jamming; a geared control system is subject to sticking due to possible deposits of dirt in the grooves of the toothing, whereas the double-lever vane- connection system does not present any possible problems of meshing between gears, and is hence more reliable in the case of dusty environments;

2. Reduced friction: the double-rod system is characterised by a greater fluidity of movement, due precisely to the lower friction that is developed during operation of the shutter; this enables the mechanism to function even with a minimum driving force; there is thus possible operation without the aid of servomotors or drives, but just exploiting the velocity of the air that passes through the shutter;

3. Reduced head losses: given the lesser effort necessary to open the shutter compared to a gear system (on account of the reduction of friction) or compared to a shutter with conventional opening (better balancing), in the case of suction-pressure opening it is possible to use vanes characterised by a profile having a reduced aerodynamic lift, thus limiting the head losses and the resistance to the passage of air; this implies a greater efficiency of the ventilation fan;

4. Economy of use: if compared to a system with opposed vanes with geared control mechanism, the present system proves less expensive;

5. More convenient maintenance: if compared to a conventional shutter with the same number of vanes, the particular spacing of the shutter with opposed vanes means more space available in the case of maintenance carried out inside the ventilation fan.

Of course, the present invention is not limited to the embodiment illustrated and described herein, but comprises variant embodiments and modifications, all of which fall within the scope of the ensuing claims.

Claims

1 . A wall-mounted ventilation fan having an air-intake shutter with suction-pressure automatic opening, comprising a balanced mechanism formed by a first bar (11 ), which carries the vanes (111 ), referred to as "gravity" vanes, that tend to close under the action of the force of gravity, and a second bar (12), which carries the vanes (112), referred to as "antigravity" vanes, that open or close in the opposite direction with respect to the gravity vanes and that tend to close under the action of elastic-return elements (16), the bars (11 ) and (12) being connected to the frame (1 ) via spring shackles (211 ) (212) so as to form two distinct articulated quadrilaterals having as fixed points the centres of rotation (311 , 312) of the vanes (111 , 112) connected together via an arm (13), which is fixed with respect to the bar (12) and carries a scotch yoke (14) provided with a cam-shaped part (14 A) with which it engages a pin (15) fixed with respect to the bar (11 ),

said ventilation fan being characterised in that, during closing, the passage of the pin (15) onto the cam part (14 A) of the scotch yoke (14) bestows on the vanes (112), owing to the action of the springs (16), a closing advance (112’) that prevents any sticking of the vanes (111 , 112) together.

2. The ventilation fan according to claim 1 , characterised in that the pins (311 , 312) are positioned in such a way that the distance between the pin (311 ) and the pin (312) positioned on it is equal to the dimension A, whereas the distance between the pin (311 ) and the pin (312) positioned underneath it is equal to the dimension B, where the dimension B is different from the dimension A so that a particular spacing is created between the vanes in the open position that is characterised by a repeated alternation of an extensive surface of passage of air and a reduced surface of passage of air.

3. The ventilation fan according to claim 1 , characterised in that, when the air shutter (S) is located downstream of the fan (3), the opening of the air shutter (S) takes place thanks to the pressure of the air acting thereon.