FR2487791A1 - Storage vessel material flow activator - comprises gas injector providing multiple instantaneous energy bursts - Google Patents

Abstract

Flow of material from a storage vessel is aided by subjecting the material to multiple instantaneous energy bursts of impact, aeration and sonic stimulation. The energy bursts are provided by a gas storage tank that connects with a bin and an electrically operated valve controlled by a programmer. The programmer emits electrical signals in the range of 20-100 milliseconds to the valve in order to inject bursts of gas into the material. A number of injectors may be employed to provide a variety of energy waves within the bin. The natural frequency or sub-multiple thereof is pref. chosen. Used for gravity feed from storage bins or hoppers. Efficiently restores free flow and removes disruptive materials with min. expenditure of time and energy.

Description

 We know the difficulties experienced with silos, hoppers and other granular material storage containers to flow by gravity these materials through a discharge hole provided at the base of the container.

Among other things, it is common, for example, to see the material get stuck in a vault, in a bridge or against the walls, these stuckings being able to result from the dimensions and the design of the silo, from the flow characteristics of the material, from the mode flow (mass or funnel), temperature, humidity and other environmental conditions and physical parameters. It is also possible that the material accumulates in recesses and at the level of sealing zones or surfaces and the like, the presence of such deposits disturbing normal operation.

Various types of apparatus and methods have been used, in an attempt to fragment the material so that it flows well, in particular vibrators and other powerful percussive devices acting on the walls of the storage containers, as well as devices projecting compressed air in the storage chamber. It has been found that devices of the last type mentioned above are not only more effective, but also of a nature to reduce the wear of the container walls and of the rest of the material, which increases the longevity of the material and reduces set-ups. forced shutdown and maintenance. Such devices according to the prior art are described, for example, in patents
US N s 2,171,398, 3,249,263, 3,861,753 and 4,067,623.

 The present invention relates to devices of the last aforementioned type, but which differ from prior devices of this type in that they generate multiple instantaneous puffs of adjustable duration (usually less than a second) for loosening the material housed in storage containers. in order to cause it to flow freely through the discharge hole. All prior devices project compressed air for much longer periods of time or continuously; however, for the reasons which will be explained, such devices are not as effective as those according to the invention, which generate multiple pulses of instantaneous energy.

Consequently, the present invention aims to
- to produce a flow stimulating device for silo or similar storage container, such as to instantly loosen the material trapped in a vault, in a bridge, against the walls or otherwise in gazelle immediately starts to flow freely through the hole container spilled.

- to evacuate efficiently the material which escapes the flow by accumulating locally in nooks or on sealed areas or surfaces, thus freezing the operation
to propose a method for restoring the free flow of granular material in bulk through the discharge hole of a silo or other storage container by means of multiple instantaneous energy pulses, in a manner which will be described.

 These objects and advantages of the invention are achieved by providing a flow stimulating device for a silo and a method for restoring the free flow of the material through the discharge hole of a silo, remarkable in that it propagates. directly into the bulk material of multiple instantaneous pulses of stimulation energy by shock, aeration and vibration in order to cause the free flow of the material through said discharge hole. In addition, in order to achieve the above-mentioned aims, the invention uses multiple instantaneous energy pulses to drive away the material undesirably accumulated in certain areas and which interferes with normal operation.

We will now describe by way of example certain preferred embodiments of the invention with reference to the accompanying drawings, in which
- Figure 1 is a schematic detail view in profile, with sections, of a silo on which are mounted two flow stimulating devices produced according to the invention;
- Figure la is a view similar to Figure 1, but on a smaller scale, illustrating a preferred method of mounting on a silo two flow stimulating devices intended to avoid jamming in the vault
- Figure lb is a view similar to Figure illustrating a preferred method of mounting on a silo of two flow stimulating devices intended to avoid jamming in bridge
- Figure lc is a view similar to Figure la illustrating a preferred method of mounting on a silo two flow stimulating devices intended to avoid jamming against the walls
- Figure ld is a view similar to Figure la illustrating a preferred mode of mounting on a silo of several flow stimulating devices intended to avoid jamming around a central channel or rat hole
- Figure 2 is, on a larger scale, a schematic detail view in profile, with sections illustrating a preferred method of mounting each flow stimulator device on a silo and also indicating the theoretical (adjustable) pattern of multiple pulses of instantaneous energy obtained by each injector
- Figure 3 is a detailed profile view of the injector which constitutes one of the components of the flow stimulating device according to the invention; and
- Figure 4 is a detailed perspective view of the injector and the programmer which constitute the flow stimulator device for silo according to the invention.

 According to the present invention, it acts on particles of loose granular material trapped in a vault, in a bridge, against the walls or in a rat hole in storage, transport or transit containers, or which accumulate in nooks , in order to make them flow freely in response to a programmed energy emission which acts directly within the bulk material in the form of multiple instantaneous energy pulses constituted by puffs of compressed gas, namely the air.

The bursts or pulses of energy preferably appear at an adjustable rate or frequency which is in each concrete case that exerting on the material an optimum stimulating effect. I1 results in an immediate restoration of free flow, which allows the material to flow through the discharge hole of the silo or other storage container. The pattern of multiple instantaneous energy pulses also acts effectively to expel material deposited locally in receptacles or on sealing areas or surfaces and which interferes with normal operation.

 Looking more particularly at the drawings, it can be seen that the flow stimulating device 10 according to the invention comprises two main components, an injector 20 and a programmer 30. The injector 20 comprises a reservoir of compressed gas 22 connected by a set of fittings and pipe 24 to an electrically controlled valve 26, mounted at one end of the compressed gas tank 22. The valve to. electric control 26 connects the compressed gas tank 22 to the silo or storage container 40 by means of a union union and elbow assembly 28, the free end of which is inserted into the silo or container 40, as shown in the Figures 1 and 2. It will be noted that the assembly of the compressed gas tank 22, the electrically controlled valve 26 and the aforementioned other components of the injector 20 has the desired arrangement so that it can be mounted very close to the silo or reservoir 40 so that the multiple pulses of energy emitted by the injector 20 can act effectively in a short time on the bulk material, this to reduce dead times to a minimum.

 The electrically controlled valve 26 (solenoid valve or the like) is designed to operate at the speeds established by the programmer 30.

 As explained below, the programmer 30 is designed to emit electrical signals with a duration of approximately 20 to 100 milliseconds; therefore, the electrically operated valve 26 must be capable of closing by mechanical response leaving only the prescribed amount of energy to propagate from the reservoir, the remainder of the energy being added to subsequent pulses for establishment 'of the predetermined pulse pattern.

 The programmer 30 is a field adjustable unit which transmits electrical signals of 20 to 100 milliseconds duration to control the injector. Each programmer 30 has any number of output channels, the number of channels suitable to meet current needs being one to six. In addition to the multiple output channels, the programmer has a timer that regulates the distribution and duration of electrical signals.

Thus, the programmer 30 determines the number of electrical signal pulses per channel, the number of channels in action, the overall activation and deactivation times per channel, the instant of activation of the following channels, the instant of repetition of the sequence of operations and the time elapsing between the start of complete programs.

The chosen program determines the exact sequence of energy pulses to be applied within the material and it is adjusted in each concrete case to obtain the preferred sequence causing the response of the material most sensitive to the action of injector 20. The choice of a program establishes one of the following modes of propagation of energy pulses within matter
(1) energy wave propagating clockwise;
(2) energy wave propagating counterclockwise;
(3) alternate propagation from opposite walls of a container
(4) alternating propagations from two injectors located in the same place;
(5) simultaneous propagation from all injectors, or
(5) any combination of the above modes.

 The JO programmer is adjusted on site to a frequency to which the material contained in the silo or container 40 is naturally sensitive, whether it is the predominant natural frequency of the bulk material or some multiple or sub-multiple of the natural frequency causing a stimulation of the flow. In some cases, the natural frequency of the material may differ from the frequencies of available patterns to the point that you can adjust the pulse pattern t in this case, the movement of the bulk material only responds to the simple effect of the pulse pattern. Whenever possible, it is better to adapt to the natural frequency of the bulk material, as this maximizes the efficiency of the energy pulses.

 The chosen program is adjusted on the spot so as to emit on each injection only the number of energy pulses necessary to cause free flow. Once the latter has been established, the flow stimulator 10 is put to rest until a new interruption in flow is detected. The stimulation is then reestablished or, as a variant, the program can be established so that the stimulation takes place at the desired intervals, according to the experience acquired, to intervene before the material is trapped in a vault, bridge or hole. rat. For most materials, the flow stimulator 10 only has to act to initiate the flow of material from the quiescent state because, once in flow, the material is automatically aerated. , it becomes necessary to activate the flow stimulator 10 only when the material stops flowing or flows at a speed allowing the reappearance of a jamming (in arch, in bridge, against walls or rat hole) under the very effect of matter. In the latter case, the flow stimulator lo can be programmed so that it acts at the time intervals required to remedy the jamming before it becomes positive.

 The common wedging modes are those in vault (figure la), in bridge (figure lb), against the walls (figure lc) and in central channel or rat hole (figure ld).

Each of these figures also indicates the positions and the arrangement to be given to the flow stimulators 10 in order to avoid common jamming modes. In addition, and although this measure is not illustrated, a pulse pattern as described here can be propagated along pipes and up to corners or sealing areas or the like where the accumulation of material is undesirable in order to effectively expel the accumulated matter.

 The general description given below of the operation is intended to make better understand what occurs, it is believed, during the emission of multiple instantaneous energy pulses.

 During its short duration (20 to loo milliseconds), each puff or pulse of injected compressed gas acts directly on the particles it meets and moves them in the direction of movement and expansion of the compressed air. Simultaneously, when the material is set in motion, it is aerated due to the expansion of the compressed gas. The programmer 30 is set so that before the particles displaced by the initial energy pulse are immobilized, a second puff of compressed gas is injected into the bulk material. Because the particles displaced by the initial puff are still in motion, and that the stimulation zone is under high pressure, the second puff generates a displacement, loosening or aeration force whose effect is more pronounced or amplifying, because we act on particles already in movement. The program is such that each subsequent energy pulse acts on particles not at rest, but animated with kinetic energy, so that the subsequent energy pulses even if their energy level is lower than that of the previous pulses, act more effectively than these due to the amplification effect. The energy level of the moving particles increases from one impulse to another until it acquires a high value and this high energy level communicates with more and more particles, stimulation by shock and aeration spreading throughout the container. The energy pulses are transmitted at a frequency, adjustable on the spot, to which the bulk material is most sensitive in order to also provide vibratory stimulation. The multiple instantaneous pulses of stimulation energy by shock, aeration and vibration act, in concert, directly on the material to cause its free flow. By judicious choice of the program as well as the locations and the number of flow stimulators 10, we can propagate to the entire storage container stimulation causing free flow in a time ranging from less than a second to a few seconds. Particles accumulated in pipes, recesses and on sealing areas and the like are also removed in a similar manner in a time of the same order.

 It is clear that the instantaneous injection of energy ensuring the described modes of stimulation (by shock, aeration and vibration), with concentration within and at the surface of the particles, can be adjusted so as to provide the precise amount of energy. necessary to ensure total stimulation with maximum efficiency.

Obtaining a maximum of stimulation with a minimum of energy depends in combination on the gas pressure, the frequency of bursts or pulses of energy, the pressure profile of these, the location and the number of injectors, as well as the setting of the programmer operated on site.

 The modes of stimulation by shock, aeration and resonance are symbolically illustrated in FIGS. 1 and 2 of the drawings in which several concentric rings which are closely grouped represent the impact forces, the aeration and vibratory forces being symbolized by profiles in the form of graphics.

 From the foregoing description, it can be seen that the device and the method for stimulating flow in a silo or other storage container make it possible to quickly and efficiently restore the flow of bulk material in a silo or to drive out the material accumulated locally in another container. In addition, by judicious choice, control and adjustment of the components of the installation, maximum efficiency can be obtained with minimum downtime and energy expenditure. On the whole, the device and the method are, by the operating mode and the efficiency, much superior to those according to the prior art.

Claims (9)

 1 - Flow stimulator intended to restore the flow of material or to expel the locally accumulated material in a container containing the material, characterized in that it comprises own means (10) to be introduced directly into the material of multiples instantaneous pulses of stimulation energy by shock, aeration and vibration to dislodge local deposits and cause free flow of material from the container containing it.  2 - flow stimulator according to claim 1, characterized in that said means (10) for introducing multiple instantaneous stimulation energy pulses by shock, aeration and vibration comprise at least one injector (20) for the introduction at the desired frequency of a compressed gas and at least one programmer (30) intended to regulate at the desired frequency the introduction by the injector of multiple pulses or instantaneous bursts of compressed gas generating an impact force.  3 - Flow stimulator according to claim 2, characterized in that the or each injector is constituted by an electrically controlled valve (26) controlled by the or each programmer and by a compressed gas tank (22) controlled by said valve electrically operated.  4 - flow stimulator according to claim 3, characterized in that said electrically controlled valve (26) and said compressed gas tank (22) are both mounted, in the immediate vicinity of one another, on said container, to minimize response time and downtime.  5 - Flow stimulator according to claim 3, characterized in that said programmer (30) sends electrical signals of a duration expressed in milliseconds to said electrically controlled valve.  6 - Flow stimulator according to claim 5, characterized in that the duration expressed in milliseconds is approximately from 20 to 100 milliseconds.  7 - flow stimulator according to claim 5, characterized in that the programmer has multiple electrical signal output channels and a timer means, and in that said programmer controls the number of electrical signal pulses per channel, the number of channels in action, total activation and deactivation time per channel, next channel activation delay, repetition of the sequence of operations and the time that elapses between the start of the full program .  8 - flow stimulator according to claim 5, characterized in that there is provided a series of injectors (20) placed in selected locations around said container, in that the or each programmer controls the direction and intensity action of each injector, as well as the relative time sequence of action of the various injectors.  9 - Method for restoring the free flow of material or expelling local deposits of material in a container containing the material according to claim 1, characterized in that directly introduced into the material multiple instantaneous pulses of shock stimulation energy , ventilation and vibrations which act directly on the material to dislodge deposits or cause it to flow freely from the container containing it.