Site News  |   Monitor Keywords  |   Monitor Archive  |   Organizer  |   Account Info  |

Diaphragm circulator

Diaphragm circulator description/claims

(1) Technical Field

This invention relates to a diaphragm circulator and, more generally, to a device whereby mechanical power is converted into hydraulic power, i.e., the product of the flow rate multiplied by the pressure, for a liquid or gaseous fluid charged or uncharged with particles, or for any material capable of flowing (divided, powdery, fluidized or emulsified materials).

(2) Description of the Prior Art

There are numerous types of pumps, suction devices, compressors, fans . . . which perform this function. A new technique has recently appeared for providing this function, at least for a liquid, by means of a diaphragm acting as an intermediate means of converting (a transfer medium) mechanical power (the integral over a time interval of the product of force multiplied by displacement) into hydraulic power (the integral over the same interval of the product of flow rate multiplied by pressure), this transfer occurring by way of a deformation and kinetic energy of this diaphragm, the deformation being propagated in the diaphragm in the form of a ripple and the corresponding energy being progressively transferred to the fluid with which the diaphragm is in contact.

The document EP 880 650 exemplifies several embodiments of such a fluid circulator while emphasizing certain requirements to be met for there to be an efficient transfer of energy between the diaphragm and the fluid, resulting in an increase in the hydraulic power of the fluid. These requirements are the establishment of tension in the diaphragm in order for there to be ripple propagation, on the one hand, and, on the other hand, the presence of means of creating a damping of the ripple amplitude during the progression thereof from an edge of the diaphragm, where this ripple is generated by a mechanical actuator, up to an opposing edge.

This document teaches the use of rigid walls as damping-creating means, the spacing of which decreases from the inlet port to the exhaust port for the fluid treated by the circulator.

Many studies have been conducted on this new device in order to better characterize the phenomena involved, which had never before been explored, and to optimize the parameters which govern these phenomena. In particular, these studies made it possible to better identify the requirements to be met, which are stated to a limited extent in the document EP 880 650, which furthermore is the only element exemplifying the prior art for this new technique.

This is how experiments showed that the tension state of the diaphragm is a variable which is correlated with the mechanical properties of the material of this diaphragm. In reality, the initial tension state of the idle diaphragm can be equal to zero if, for example, the diaphragm is made of a material which is elastically deformable in at least one direction, combined with a geometry such that imposing a deformation on the diaphragm produces tension therein, in the aforesaid direction, which enables progression of this deformation in the form of a ripple, along this direction, which becomes the direction of propagation. Hereinafter, this type of diaphragm will be referred to as a diaphragm having intrinsic tension-creating means. For example, this will involve an elastic disk-shaped diaphragm, with or without an opening at the centre, wherein the outer edge remains undeformed during the excitation thereof by the actuator, while the idle diaphragm is not tensed. It may likewise involve a flat elastic diaphragm wherein the two ends are subjected to forces which oppose the forces imparted to the diaphragm by the fluid in which the energy is transferred. Owing to the presence of these forces, the conditions necessary for the propagation of a deformation produced at one end towards the other end are present.

It was also observed that a diaphragm consisting of a sheet which is flat when idle, non-deformable under tension, in the directions of the plane thereof, but elastically deformable under bending, e.g., about an axis contained within this plane, constitutes a medium enabling operation like a diaphragm according to the invention, if the diaphragm is subjected to a tensile or simply holding force perpendicular to or having a component which is perpendicular to the axis about which the bending occurs. This perpendicular direction is the direction of propagation.

Furthermore, theoretical and experimental research made it possible to clarify that it was possible to create a forced damping of the ripple amplitude without necessarily having to decrease the spacing of the stationary walls between which the diaphragm ripples. As a matter of fact, an excitation of the actuator resulting in the application of an reciprocating force or an reciprocating couple of given frequency and amplitude forces, at an edge of the elastic diaphragm placed inside the fluid, in the absence of walls surrounding it, generates ripples capable of propagating along the diaphragm towards the side thereof which is opposite the excited side, with a free amplitude which may be characterized by envelope surfaces of this amplitude. In order to visualize these envelope surfaces, a reflectionless propagation of waves or ripples considered, i.e., in the (theoretical or virtual) case where the diaphragm is of infinite length or the evolution of the amplitude of a primary ripple between a first instant, after the creation thereof, and a second instant separated from the first by a relatively short time interval, considering the dimensions of the diaphragm. The shape of these surfaces depends on the nature of the excitation of the diaphragm edge. Thus, in the case of excitation by means of an actuator which moves the edge of the diaphragm, the envelope surfaces will have a divergent bell-shaped profile; in the case of an actuator transmitting a couple of forces to the edge of the diaphragm, the surfaces will instead have the profile of two curves secant to the axis about which the torque is transmitted. Force damping of this ripple is obtained if stationary walls between which the diaphragm ripples are placed between (inside of) these envelope surfaces.

This condition does not necessarily eliminate a decrease in their spacing, as is described in the document EP 880 650. For particular diaphragm geometries and types, and particularly in a gaseous fluid, it is indeed possible to observe that the envelope curves diverge between the excited edge and the opposite edge of the diaphragm, thus, by simply reducing the degree of divergence, hydraulic power is successfully transferred into the fluid. The greater this reduction, the greater the preference given to the pressure component in this energy. The type of material comprising the diaphragm as well as the uniformity thereof, or the lack of uniformity thereof, in the direction of progression of the ripples, are also determining factors in the shape of the envelope surfaces of the amplitude of a ripple during the propagation thereof into the diaphragm, and are therefore determining factors in the shape and relative spacing of the rigid walls which create the forced damping of this ripple. In particular, for a uniform diaphragm, it is advantageous to provide for the thickness thereof to decrease in the direction of propagation of the ripples. The envelope curve of a tapered diaphragm such as this is more divergent than for a diaphragm of constant thickness, all things being otherwise equal. Due to this diaphragm geometry, a high damping factor is obtained, since stationary walls can be well within these envelope curves.

These observations and experimental research enabled the subject matter of the invention to be defined as a diaphragm circulator for a flowable material, comprising a circulator body wherein an internal circuit is arranged, which has at least one inlet port for the material, one propulsion chamber and at least one discharge port for this material, the propulsion chamber having rigid walls between which a deformable diaphragm is placed, with one edge adjacent to the inlet port and one edge adjacent to the discharge port, the diaphragm forming the support for a ripple, while a mechanical actuator for the diaphragm is connected to the diaphragm on the inlet port side, in order to apply an reciprocating force or a couple of reciprocating forces generating said ripple to the corresponding edge of the diaphragm, wherein the rigid walls of the circulator are arranged inside of envelope surfaces of the free amplitude of the ripple propagating along the diaphragm, and wherein the diaphragm is associated, via at least one of the edges thereof, with means which create tension in the diaphragm, at least during generation of the ripple, whereby, during operation, the prevailing tension in the diaphragm is higher on the discharge port side than on the inlet port side.

This variation in tension in the diaphragm is a result of the trussing effect on the diaphragm by the fluid having acquired hydraulic energy along the entire propulsion chamber.

In the above definition of the circulator according to the invention, the free amplitude of the ripple should be understood to mean the theoretical or virtual amplitude that was defined above. This definition is neither disclosed nor suggested by the circulators of the prior art (EP 880 650), i.e., those which have both a circulation chamber the walls of which converge towards one another from the inlet port to the discharge port, and a diaphragm in which tension is voluntarily established in the direction of the fluid flow. However, this definition relates to all circulators which, while having a circulation chamber with converging walls, also have a diaphragm the dimension of which, in the direction of ripple propagation, is set by appropriate means so that in the diaphragm, even without any initial tension, the elongation of the diaphragm which accompanies the creation of a ripple generates tension in the direction of ripple propagation, the diaphragm being made or not made of a material that is elastically deformable in the direction of propagation. These are intrinsic means of establishing this tension condition necessary for propagation. Other examples of this type of means exist: a frame in the interior plane of which the diaphragm is attached to the end crossmembers of this frame, either by inextensible means, if the diaphragm is elastic between these two crossmembers, or by extensible means, if the diaphragm is inextensible between the crossmembers (e.g., a flat sheet, made of metal or a composite synthetic material, capable of bending about a direction of the plane thereof). An initial tension may or may not be established when the diaphragm is mounted in the frame. These arrangements can be transposed in the case of tubular diaphragms provided with elastic radial extensibility.

In the case of a disk-shaped diaphragm, this requirement is met if the peripheral edge of the diaphragm is integral with a non-deforming band, the diaphragm having the possibility of being solid or perforated at the centre thereof with an opening the edge of which is a means of immobilizing the diaphragm truss in the direction of ripple propagation. The dimensional characteristic of the diaphragm would not be achieved if, for example, the edge of the centre hole thereof were provided with radial incisions, which would destroy the expansion resistance of the opening.

The non-deforming outer banding of the diaphragm can consist of a bead belonging to the diaphragm itself, which is non-deforming with respect to the loads involved, which may be light.

The term “rigid walls” should also be understood to mean walls which, in absolute terms, may however possess a certain degree of flexibility, but which, when applied to use, behave like rigid walls with regard to all of the other materials involved in the device.

In a first embodiment of the invention, a portion of the propulsion chamber is defined by the circulator body and one of the faces of the diaphragm is connected to an inlet port for an external supply of a material being treated, and, in particular, propelled, and to a discharge port which is itself connected to the inlet port of the other portion of the propulsion chamber defined by the circulator body and the other face of the diaphragm, this other portion terminating at the circulator discharge port, the two chamber portions being otherwise separated from one another.

In this embodiment, a circulation stage is created on each side of the diaphragm, which, all things otherwise being equal, makes it possible to obtain a greater pump pressure performance or, at equal performance, to be capable of choosing a diaphragm material which has a lower modulus of elasticity but which is better suited to the chemical specifications of the application. In particular, this increased performance can be obtained with the over dimensions being unchanged. In another embodiment, the circulator comprises a disk-shaped diaphragm the outer periphery of which is attached to a moving excitation assembly which is guided along an axis perpendicular to the plane of the diaphragm by a centre guide column integral with the circulator body. This type of excitation device is advantageous because it concentrates all of the motorizing and guiding functions at the central axis of the circulator, functions which can be provided at reduced dimensions, which enables them to be obtained at a low cost. The motorization and guidance of the moving parts are in fact the most costly functions of the circulator. For example, it is easy to motorize by means of a plunger core electromagnet with a return spring, the core, which slides along the guide column, being attached to a stirrup clamp for the connection thereof to the periphery of the diaphragm, thereby forming the moving assembly.

In a yet simpler embodiment, the moving assembly comprises an annular permanent magnet surrounding the guide column, which forms the plunger core for a magnet coil and armature arranged around the permanent magnet.

The circulator according to the invention can have a substantially cylindrical body which defines several superimposed propulsion spaces connected in series between an inlet port and a discharge port, the diaphragms of each space being attached via the outer edge thereof to a single moving motorization assembly. In this way, a circulator is obtained with compact design, which is capable of supplying a fluid under high pressure.

• Provisional Patent
• Utility Patent

• What Is a Patent?
• What Is a Trademark or Servicemark?
• What Is a Copyright?
• Patent Laws