Abstract:
This invention relates to an automatic flowrate regulator for ventilation and air-conditioning installations, wherein it comprises a rigid flap articulated in the body and which is subjected, on the one hand, to elastic means, on the other hand, to the pressure of the air stream, this antagonistic action ensuring control of said flap which at any moment leaves free a section adapted to ensure balancing of the installation.

Description:
FIELD OF THE INVENTION 
     The present invention relates to an automatic flowrate regulator intended for equipping the terminal conduits of ventilation, air-conditioning or like installations, with a view to maintaining a determined flowrate independently of the pressure variations. 
     BACKGROUND OF THE INVENTION 
     Up to recent times, this result was obtained with the aid of manually manoeuvred adjusting flap valves, constituted in fact by apparatus similar to slide valves. As initial adjustment of the flap valves proved to be delicate and the characteristics of the installation varied in time, automatically operating regulators have been proposed, making it possible, by modifying the section of air passage, to obtain a constant flowrate whatever the variations in the pressure inside the conduits. 
     In known regulators, the section of passage is modified with the aid of a mobile member on which the pressure of the air conveyed and suitably arranged elastic means act in antagonism. However, experience has shown that the constructions proposed are complex and expensive, frequently prove to function noisily and present a range of regulation of low amplitude, unstable in time. 
     It is an object of the present invention to overcome these drawbacks. 
     SUMMARY OF THE INVENTION 
     To that end, the automatic flowrate regulator of the type described above comprises, in combination: 
     a tubular body adapted to define a conduit presenting two parallel plane walls joined by a plane wall and by an arcuate wall, said body being arranged to be connected to a pipe; 
     a rigid flap which, presenting a profile similar to that of the section of the conduit mentioned above, is articulated on the body transversely with respect to the axis of the conduit thereof and which is associated with two stops which define a position of maximum closure and a position of maximum opening, this latter forming a pressure chamber which is closed at the level of the articulation of the flap and which opens upstream in the sense of circulation of the air; 
     elastic means associated with the flap with a view to returning the latter to the position of maximum opening; 
     and a damper of which the mobile member is coupled to the flap with a view to eliminating the pumping effects. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be more readily understood on reading the following description with reference to the accompanying drawings, in which: 
     FIG. 1 is a view in perspective illustrating the general arrangement of an automatic regulator according to the invention. 
     FIG. 2 is a schematic axial section of the regulator according to FIG. 1. 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENT 
     Referring now to the drawings, the regulator in question comprises a tubular body 1 which will be assumed to be made of moulded plastics material, which body comprises at least one end collar la adapted to fit on a pipe C. The axial opening of the body 1 defines an air passage conduit which presents two opposite plane walls 1b oriented parallel to each other, a plane wall 1c oriented perpendicularly to said walls 1b, and a wall 1d of arcuate or vaulted profile facing said wall 1c. 
     Body 1 contains a rigid flap 2 which is dimensioned in width so as to fit with reduced clearance between the parallel walls 1b of the conduit. The lower face of this flap 2 comprises a tab 2a turned obliquely downwards, of which the free end is fast with two catches 2b which project outwardly in order to engage in corresponding depressions in the body 1 and thus to form a pivot axis for said flap. 
     It will be observed that the transverse edge of this flap 2 which is opposite the collar 1a, beyond axis 2b, is curved in the direction of the corresponding part of the body 1 in order to define a sort of beak 2c adapted to abut against the body 1 with a view to constituting a stop limiting tipping of the flap 2 into closure position. To this maximum stop 2c there corresponds a minimum stop constituted by two lateral flanges 2d fast with the lower face of the flap 2 to abut against the wall 1c of the conduit. 
     With flap 2 are associated elastic means for return into open position, which are constituted by one or more blades 3 inserted in a slot provided to the rear of the tab 2a in order to be applied against the body 1, below beak 2c. Opposite these elastic means 3 there is provided a damper 4 which comprises a piston 4a connected to the lower wall of the flap 2, which piston is engaged to slide in virtually tight manner in a cylinder 4b which is itself connected to a small bracket 5 clipped in an opening of the wall 1c. 
     Operation of the regulator according to the invention follows from the foregoing explanations and will be readily understood. 
     When the air contained in pipe C is not under pressure or at least the air stream which traverses said pipe and the conduit of the regulator presents only a low differential pressure, the action of the elastic means on the flap 2 is preponderant, so that said flap is maintained in the fully open position for which the flanges abut against the wall 1c. However, it should be observed that, in this position, the presence of said flanges 2d makes a free space between the lower face of the flap and the wall 1c of the conduit, which free space, open in the direction of pipe C, i.e. towards upstream in the direction of circulation of the air (arrow F), acts as pressure chamber, referenced 6 in FIG. 2. 
     Under these conditions, when the pressure in this chamber 6 increases, the flap 2 rises against the elastic means 3, thus reducing the surface of the section left free in the conduit by said flap. The flowrate of air is thus automatically reduced, until a position of equilibrium between the differential pressure prevailing on either side of the regulator and the elastic return means, is attained. This position of equilibrium determines a free section of air passage corresponding to a flowrate as a function of the said differential pressure, it being noted that the bearing surface of the beak 2c against the body 1 in any case limits the angular displacement of the flap and avoids too great an obturation. 
     A regulation of the flowrates in such or such branch of a network as a function of needs is therefore obtained, independently of the different pressures prevailing in the network in question of the ventilation installation with which the regulator is associated. Due to this arangement, the damper 4 associated with the flap 2 in no way hinders the slow angular displacement of said flap; it intervenes only to oppose the phenomena of &#34;beat&#34; or of &#34;pumping&#34; of which the flap valves of ventilation installations are frequently the seat. 
     It goes without saying that, for the precise adaptation of the regulator according to the invention to the flow characteristics of the installation for which it is intended, section reducers may be provided, fixed removably, for example by simple elastic clipping, in that part of the conduit which is not occupied by the flap 2, i.e. at the level of the arcuate wall 1d. 
     It must, moreover, be understood that the foregoing description has been given only by way of example and that it in no way limits the domain of the invention which would not be exceeded by replacing the details of execution described by any other equivalents.