FR2604223A1 - Hydraulic logic module and modular apparatus comprising it - Google Patents

Abstract

The invention relates to a hydraulic logic module. It concerns a module comprising a chamber 10 which is open at its upper part and has two inlets 14, 16 for a current of liquid having a nominal flow rate. A first outlet circuit is connected to the bottom of the chamber 10 and comprises a siphon and a second outlet circuit 28 is connected halfway up the chamber via a contraction 30. When only one current is transmitted, only the second circuit transmits a current whereas when two currents are present at the inlet, only the circuit 20 transmits a current. Application to the simulation of logic processes for teaching and research.

Description

 The present invention relates to a hydraulic logic module and a modular apparatus comprising it, intended essentially for teaching the principles and implementation of combinatorial logic, but also suitable for other applications, in particular playful and aesthetic.

 The combinatorial logic on which the operation of computers is based, is implemented in circuits having dimensions of a few microns or tens of microns and having response times of a few tens of nanoseconds. These dimensions and these durations are far too small for it to be possible to easily observe the various phenomena involved. The invention relates to a hydraulic simulation allowing the implementation of combinatorial logic operations in circuits having a few centimeters or tens of centimeters, with response times of the order of a few seconds; This simulation therefore allows the understanding of the different processes implemented. These processes are simple to understand when it is an elementary door but the operations are much more difficult to elucidate when several doors are mounted in series and in parallel.

 The invention uses a certain analogy between electric currents and hydraulic currents, the electric voltage being represented by a height of fluid, that is to say a hydrostatic pressure.

 The invention uses, as a fundamental element, a module constituting, in parallel, an AND gate and an exclusive OR gate. This module has two inputs and two outputs, one of the outputs transmitting a current of liquid only when only one of the two input currents is present, and another output transmitting a current only when the two input currents are present.

More specifically, the invention relates to a hydraulic logic module which comprises - a dedicated chamber & another arranged vertically and having two liquid inlets placed at the upper part of the chamber and two outlets placed at different heights,
a first outlet circuit connected to the lowest outlet of the chamber and comprising a siphon rising higher than the highest outlet, and
- a second output circuit connected to the highest output1
- the impedances of the two circuits being such that
a) when only one of the inputs transmits a nominal flow current, the level is established in the chamber between the second output and the highest part of the siphon of the first output, so that only the second circuit transmits a current liquid,
b) when the two inputs transmit a nominal flow, the level rises higher than the highest part of the siphon and thus causes the priming of the siphon, the level then descending to establish a height between those of the two outputs, and
c) when the nominal flow of one of the two inlets is then interrupted, the level drops below the lowest outlet and causes a defusing of the siphon.

 Preferably, the first output circuit has an impedance distributed throughout the pipe and having a progressive widening at the bottom.

This last characteristic favors defusing the siphon
The second output circuit also preferably includes a throttle adjacent to the highest output, this throttle giving a suitable impedance to the second output circuit.

 The chamber and the two output circuits are advantageously formed in the same body. This is preferably made of a transparent material. The liquid used is preferably colored.

 The first output circuit also preferably includes a flow limiter, intended to deflect the excess flow with respect to the nominal flow.

 In a particular embodiment, the module is itself placed in a transparent enclosure which can be filled with a liquid circulating between an upper inlet and a lower outlet.

 The invention also relates to a modular hydraulic logic device, comprising at least one module as described above, a liquid distributor placed at the top of the device, and a liquid collector placed at the bottom of the device.

The device also advantageously comprises a pump intended to return the liquid from the collector to the distributor.

 In the particular embodiment in which the modules are arranged in an enclosure having an inlet and an outlet, the apparatus advantageously comprises several modules placed one above the other and one next to the other in such a way that the first output circuit of an upper module is connected to the input of the enclosure placed around the module located just below the upper module, and the second output circuit and the output of the enclosure of the upper module are connected to module inputs that are adjacent to the lower module.

 Of course, the assemblies of modules in an apparatus according to the invention can be very diverse and depend essentially on the logic functions which must be implemented.

Other characteristics and advantages of the invention will emerge more clearly from the description which follows, given with reference to the appended drawings in which
Figures 1 & 4 schematically represent a hydraulic logic module according to the invention, at four different stages of its operation;
Figure 5 is a diagram of a flow limiter advantageously used with a hydraulic module as shown in Figures 1 to 4
Figures 6 and 7 are diagrams showing the combination of two modules according to the invention respectively constituting an AND-NO gate and a comparator
FIG. 8 represents another assembly of two modules according to the invention, forming a complete adder;
FIG. -9 is a plan view of an example of a logic module body according to the invention, in a first embodiment ;;
Figure 10 is a schematic section of an accessory useful in cooperation with the module of Figure 9;
Figures 11 and 12 are diagrams of modules introducing more complex logical relationships than before and having many possible states
Figure 13 is an electronic diagram showing the functions implemented in a module according to the invention as shown in Figures 1 to 4
Figure 14 is an example of mounting several modules of Figures 11 and 12 forming a cellular automaton
FIG. 15 is an electronic diagram of an apparatus comprising a decoder and a comparator and intended to indicate whether an operator has correctly determined which decimal digit corresponds to a binary 3-bit number
Figure 16 is a diagram of an apparatus adding two 4-bit binary numbers; and
FIG. 17 is an example of simulation which can be obtained by using an apparatus as shown in FIG. 14.

 Figures 1 to 4 show an example of a hydraulic logic module according to the invention, in a tick diagram form. This embodiment is shown formed of glass tubes. I1 comprises a body delimiting a chamber 10 placed vertically and the upper part 12 of which is open. Two inputs 14, 16, each intended to transmit a nominal flow rate, penetrate through the mouth 12 but leave the communication with the atmosphere. The chamber 10 has, at its lower part, a first outlet in the form of an orifice 18 to which is connected a first outlet circuit 20 in the form of a siphon having an upper part 22. The impedance is distributed along the circuit , and the external branch preferably ends with a flare facilitating the defusing of the siphon.

 The chamber 10 has, in addition, above its bottom but below the upper part 22 of the siphon, another orifice 26 to which a second output circuit 28 is connected. This has a throttle 30 adjacent to the orifice 26.

 The module described therefore has two inputs 14, 16 and two outputs 20, 28. We first consider an initial state as shown in FIG. 1, in which only one of the two inputs 14 transmits a nominal rate. The liquid accumulates in the chamber 10 at a certain height as indicated by the level 32. The impedance of the output circuit 28 is such that the level 32 is established at a height between that of the orifice 26 and that of the upper part 22 of the siphon. In this way, no liquid flows through the first outlet circuit 20 and the second outlet circuit 28 therefore transmits the nominal flow rate, as indicated by the arrow indicated in FIG. 1.

 It is now assumed that the two inputs transmit a nominal flow rate, so that the second output circuit 28 does not allow the evacuation of such a double flow rate.

Consequently, the level rises as indicated in reference 34 and, when it exceeds the level of the highest point of the siphon 22, the siphon starts. The impedance of the first output circuit 20 is much lower than that of the first circuit 28 so that this first circuit then evacuates fluid with a flow rate greater than twice the nominal flow rate. Consequently, the level 34 descends rapidly and soon reaches the level of the level 36 indicated in FIG. 3 and stabilizes at this level. Consequently, after the transient state represented in FIG. 2, the module remains in the stationary state of FIG. 3 as long as the two inputs 14, 16 transmit a current of nominal flow each.

 It is now assumed that one of the two inputs ceases to transmit a nominal flow current so that only one of the two inputs supplies the circuit. As the siphon is primed, it evacuates the remaining liquid and defuses because the flow of a single inlet does not allow the maintenance of the first outlet circuit in primed form. Then, the single entry begins to fill the chamber 10 and brings the module back to the state shown in FIG. 1.

 Consequently, the module shown in Figures 1 to 4 has three stationary states. The first stationary state corresponds to Figure 1: the module receives a single nominal flow current. The second stationary state is that of FIG. 3: the module receives two currents each having the nominal flow rate. Finally, the third stationary state is that in which neither of the two inputs 14, 16 transmits a current so that the apparatus does not transmit any liquid current either and remains either completely empty as shown in FIG. 4, or full up to the level of the orifice 26, according to the state from which the supply was interrupted.

 Thus, in steady state, the module transmits no current when it receives no current, it transmits a current through output 28 when it receives a single current, and it transmits a current through output 20 when it receives two currents. Its operation can be represented by the electrical analogy of FIG. 13 in which the references identical to those of FIGS. 1 to 4 denote the elements corresponding from the electrical point of view. In this figure, we note that the output 28 is that of an exclusive OR gate 38, since it 'transmits a signal only when one or the other only of the two inputs 14, 16 receives a signal. When the two inputs receive a signal, the AND gate 40 transmits a signal by output 20.

 Specialists in combinatorial logic may note that an electronic circuit as shown in Figure 13 allows the reconstruction of all logic functions. However, it should be noted that, unlike the electrical analogy, the output 20 transmits a hydraulic current equal to twice the normal flow. One can use the device shown in Figure 5 in order to have, at the output of circuit 20, the nominal flow and not a flow which is double. To this end, FIG. 5 simply represents the output of the first circuit 20 with its throttle 24. The flow twice the nominal flow reaches a tank 42 which is divided into two compartments 44, 46 by a partition 48. The compartment 44 which is located just below the end of the first outlet circuit 20 has an outlet provided with a throttle 50 such that, when the liquid arrives at the upper part of the partition 48, the flow transmitted is equal to the nominal flow .

The excess overflows over the partition 48 and is discharged through an orifice 32 of large dimensions, towards a discharge.

 It is therefore noted that, when the first output circuit is provided with a device as shown in Figure 5, the modules as shown in Figures 1 to 4 can be stacked in cascade in different ways.

When the module is to be used as a door
AND, the current from the second output circuit 28 is rejected and only the current transmitted by the first output circuit 50 is used.

When the module is to be used as a circuit
Exclusive OR, only the current from the second circuit 28 is used, the current from the first output circuit 20 being rejected.

 When the module constitutes an OR circuit, the module is useless since it suffices to use a device as shown in FIG. 5. However, the module can then be used, the two output circuits 20 and 28 both transmitting their output current to the device shown in Figure 5.

 When the module is to be used as an inverter circuit, one of the two inputs continuously transmits a current of nominal flow, and the second output circuit 28 transmits a current which is the inverse of the current transmitted by the other input.

 The module can also constitute a flow doubler.

In this case also, one of the inputs continuously transmits a nominal flow current, and the first output circuit 20 then transmits a current whose flow is equal to twice the flow of the other input.

 Finally, the module can constitute an adder.

The current from the second output circuit 28 represents the units and the current from the first circuit 20 represents the carry.

 We now consider, with reference to FIGS. 6, 7 and 8, well-known logic functions, obtained by implementing two logic modules according to the invention, connected in cascade.

 Figure 6 shows an AND-NO (NAND) gate.

The two nominal currents are received at the input of the upper module 54, and only the current of the first output circuit is transmitted to an input of the second module 56. The second input of this second module 56 permanently receives a current of nominal flow . The signal is in the form of the current from the second output circuit of module 56. The first module 54 has an AND function and the second 56 has a function
NO.

 In FIG. 7, a first module 58 receives two currents representative of the two signals which must be compared, and the current of the second output circuit is transmitted to an input of the second module 60. The latter receives a direct current of nominal flow at his other entry.

The comparison signal is transmitted by the second output circuit of the second module 60. The first module 58 plays the role of an exclusive OR gate, and the second that of an inverter.

 FIG. 8 represents a complete adder comprising a first module 62 which receives the two pieces of information at its two inputs. Its second circuit feeds one of the inputs of the second module 64 while its second circuit feeds a flow limiter 66 as shown in FIG. 5, in cooperation with the first circuit of module 64. The second input of module 64 receives a current representative of the possible retention of a previous stage.

The second output circuit of the module 64 transmits a signal representing the sum and the limiter 66 transmits a signal representing the reserve transmitted to a subsequent stage.

 This complete adder of FIG. 4 is used in the binary adder represented in FIG. 16, described in more detail later in this memo.

 FIG. 9 represents a particular embodiment of a hydraulic logic module according to the invention. This module is formed in a relatively thick plate of a transparent plastic material such as polymethyl methacrylate. This plate 68 comprises, on one face, a peripheral groove 70 intended to house a seal ensuring the seal against a flat plate closing the various cavities formed in the plate 68.

In fact, the plate 68 is hollowed out at various depths, for example by milling, so that it forms an entire hydraulic circuit. The largest cavity is a chamber 72, the upper part of which is connected to two channels 74 which are connected to the outside by cylindrical holes 76 which open onto the edge of the plate 68.

An additional small hole 78 also opens on the edge and is intended to bring the top of the chamber to atmospheric pressure. The bottom 80 of the chamber is connected to a shallower but still relatively wide channel which rises along the chamber. up to a smaller transverse part 82 intended to form the top of the siphon.

A descending branch of the first output circuit joins a relatively wide chamber 84 formed at the bottom of the plate. This chamber communicates with a cylindrical hole 86 which opens onto the edge of the plate.

 The second output circuit comprises a small diameter channel 88 which opens into the chamber 62 above its bottom. This small channel 88 opens into a wider branch which, at its upper part, communicates with the atmosphere through a hole 90 which opens onto the edge of the plate 68. The lower part of the second output circuit opens into a reservoir 92 which communicates with a cylindrical hole 94 which opens at the edge of the plate 68. The two chambers 84 and 92 are connected to each other and to a transverse hole 96 which allows the evacuation of the overflow of fluid, if necessary .

 Thus, we recognize all the elements of the block diagram of Figures 1 to 4. However, the device can advantageously include a flow limiter incorporates.

This comprises the nozzle shown in FIG. 10.

This is intended to enter the hole 86 formed in the lower part of the plate 68. It comprises a section of tube 98 ending in a narrowed hole 100 which creates a pressure drop such that the nozzle normally transmits a current of liquid at nominal flow. An O-ring 102 is housed in a groove formed on the outside of the tube section so that it seals in the hole 86.

A shoulder or a collar 104 prevents the nozzle from penetrating too far into the hole 86.

 FIG. 16 represents an apparatus intended for adding two four-bit binary numbers, formed on the basis of complete adders as represented in FIG. 8. However, in this embodiment, for educational reasons, the chamber represented in FIG. 1 has been divided into two chambers connected by three tubes, two at the top and one at the bottom. However, moreover, the operation of the various modules is identical to that which has been described.

Note the presence of three complete adders as shown in Figure 8, the first adder being simplified since it does not receive current representative of a carry. The upper and lower parts of the device include hydraulic display devices indicating whether the corresponding bit is a 1 or a 0. These display devices are NO circuits (as already described} having a form of 7 or 0 and thus allowing a display. In addition, it is important to note that the operation of the device requires the presence of a liquid distributor 128 intended to supply the various inputs and of a collector 130 intended to collect the liquid which has passed through the various modules. In addition, the device can operate continuously when it includes a pump 132 which returns the liquid from the collector 130 to the distributor 128, preferably after purification in a filter 134. The device further comprises a collector 136 of excess currents, that is to say of the overflow of the flow limiters.Of course, this collector joins the previous collector so that the liquid can circulate again.

 FIG. 15 represents, in the form of its electronic analogy, another circuit which can be produced easily. The apparatus essentially comprises a decoder 140 and a comparator 142. Its role is to indicate whether that of the eight solenoid valves 146 which has been opened by an operator corresponds to the decimal digit which represents the three-bit binary number materialized by the command of three solenoid valves 144.

 The apparatus first comprises a liquid distributor 148 which supplies the solenoid valves 144 on the one hand and the solenoid valves 146 on the other hand. The solenoid valves 144 supply the decoder 140, based on AND gates, which itself supplies the comparator 142 based on exclusive OR gates.

The solenoid valves 146 of which only one is open at a given time, allow the supply of a second input of the exclusive OR gates of the comparator 142. The outputs of the comparator 142 arrive via a circuit
OR 154 at an OR-exclusive gate 156. It should be noted that one of the two currents received by gates 154 and 156 comes from logic circuit 152 which is intended to indicate whether several solenoid valves 146 have been controlled simultaneously. When these solenoid valves have actually been controlled, a device 166 indicates this. An amplifier 158 advantageously receives the output current from gate 156 and circuits 160 and 162 respectively indicate whether there is indeed a coincidence between the three-digit binary number and the decimal number corresponding to the solenoid valve ordered. All the liquid streams reach a collector 164 which is connected to the distributor 148 by means of a pump 168.

 We now consider a module having a more complex circuit according to the invention, based on the aéja module described but comprising an additional function.

More specifically, Figures 11 and 12 show two modules which are symmetrical to each other. We therefore only describe in detail the module 11. We recognize the chamber 106 which is supplied by two inputs 108. It comprises a first output circuit 110 comprising a siphon, the second output circuit carries the reference 114. It is thus noted that the two inlets are facing two upper corners and the second outlet is facing a lower corner. On the other hand, the first exit is located appreciably in the axis of the room. Note also that the upper part of the second output circuit 114 is connected to the upper part of the chamber 106 so that the pressures are balanced.

 The entire module described is housed in a sealed enclosure 118, shown with a hexagonal shape and which has an inlet 120 for a stream of liquid, substantially placed on the axis of the assembly. In addition, a conduit 122 forms an overflow opening at a lower corner and having a calibrated orifice 123 giving the nominal flow.

 FIG. 12 is symmetrical with FIG. 11, that is to say that only the output 114 of the module and the output 122 of the enclosure are functionally reversed.

 The device shown in Figure 11 therefore has an inlet and a seam more than the modules according to the invention. A liquid can be contained in the chamber 106 and in the associated conduits, and another liquid or the same liquid can be contained in the enclosure, around the module. The modules can be assembled as shown in Figure 14 in which the modules 124 are for example of the type shown in Figure 11 and the modules 126 are those shown in Figure 12. It is noted that the three inputs of a module are connected to three outputs of three different modules of a previous line and that the three outputs are connected to three inputs of three modules of a next line. Consequently, the state of an element depends on the state of three elements above. Such a device constitutes a "cellular automaton" constituting a model for various physical and biological phenomena such as the growth of crystals, the phenomena of turbulence, the formation of waves, the growth of living beings, etc.

 Note in FIG. 14 that a horizontal line of elements according to the invention constitutes the state of a line of cells at a given time, and that the following line represents the state of the same line of cells, at a later time. We can therefore produce sets representing the evolution of a system over time.

 In the elements of Figures 11 and 12, the enclosure can be either full or empty. The module chamber can be either empty, full, or half full.

In addition, taking into account the thicknesses and volumes of the enclosure and of the module, the enclosure can be of light color and the chamber of the module of dark color. FIG. 17 represents the evolution of a line of 27 cells, over time, that is to say during 39 successive transformations. In this figure, each square represents in the central part the empty, half full or full state of the chamber of the central module, and the grayed part indicates that the enclosure is full. The fixing of a state of the elements of the first line causes a progressive evolution until the bottom of the whole of the apparatus, and the state is maintained until the first line is modified again, by command solenoid valves that supply it.

 The modules and apparatuses according to the invention are advantageously formed entirely or largely from a transparent material. For example, the modules of FIGS. 1 to 8 are advantageously formed from transparent glass, but they can also be made of plastic, in particular in the case of the modules of FIG. 10. Any transparent material resistant to the action of liquid used is generally suitable.

 The liquid used can simply be water, preferably colored, or any other suitable fluid preferably having a low viscosity. This fluid also advantageously contains a dye. Many fluids have a suitable viscosity. However, it is desirable that the fluid used be resistant to degradation under the conditions of use and in particular to air. It is therefore desirable for it to be a silicone oil.

 It is desirable to adapt the exact dimensions of the modules to the liquid used, since the surface tension and other physical properties of the liquid used can slightly modify the parameters which can be determined by calculation.

Claims (10)

 1. Hydraulic logic module, characterized in that it comprises  - a chamber (10) intended to be arranged vertically and having two inlets (14, 16) of liquid placed at the top of the chamber and two outlets placed at different heights,  a first outlet circuit (20) connected to the lowest outlet of the chamber and comprising a siphon rising higher than the highest outlet, and  - a second output circuit (28) connected to the highest output  - the impedances of the two circuits being such that  a) when only one of the inputs transmits a nominal flow current, the level is established in the chamber between the second outlet and the highest part of the siphon of the first outlet circuit, so that only the second outlet circuit transmits a stream of liquid,  b) when the two inputs transmit a nominal flow, the level rises higher than the highest part of the siphon and causes the priming of this siphon, the level then decreasing to settle at a height between that of the two outputs and  c) when the nominal flow of one of the two inlets is then interrupted, the level drops below the lowest outlet and causes a defusing of the siphon.  2. Module according to claim 1, characterized in that the first output circuit (20) further comprises a flow limiter (66) intended to divert the excess flow with respect to the nominal flow.  3. nodule according to one of claims 1 and 2, characterized in that the first output circuit (20) has a distributed impedance, and the second output circuit (28) has a throttle adjacent to the most high.  4. Module according to any one of the preceding claims, characterized in that the chamber (10) and the two output circuits (20, 28) are formed in the same body of a transparent material.  5. Module according to any one of the preceding claims, characterized in that the liquid intended to circulate in the module is colored.  6. Module according to any one of the preceding claims, characterized in that it is placed in a transparent enclosure (118) which can be filled with a liquid flowing between an upper inlet (120) and a lower outlet (122).  7. modular hydraulic logic device, characterized in that it comprises at least one hydraulic logic module according to any one of claims 1 to 6, and  - a liquid distributor (128) placed at the top of the device, and  - a liquid collector (130) placed at the bottom of the device.  8. Apparatus according to claim 7, characterized in that it further comprises a collector (136) of the excess flow exceeding the nominal flow.  9. Apparatus according to one of claims 7 and 8, characterized in that it further comprises a pump intended to return the liquid from the collector to the distributor.  10. Apparatus according to any one of claims 7 to 9, characterized in that the modules are each placed in a transparent enclosure (118) which can be filled with a liquid flowing between an upper (120) and a lower outlet ( 122), the apparatus comprising several modules arranged one above the other, and the first output circuit (112) of an upper module is connected to the input (120) of the enclosure placed around the module arranged just below, and the second output circuit (114) and the output (122) of the enclosure are connected to inputs (108) of modules adjacent to the lower module placed just below.