FR2513885A1 - Control for anaesthetic respirator - has two driving chambers and single feed chamber with interconnected pistons controlling gas intake valves - Google Patents

Abstract

The respirator includes two driving chambers and one chamber (1) feeding the gas into the patient's circuit. A valve is positioned in the circuit to maintain the pressure on the membrane of the feed chamber at a level of the same order as the max. required for the patient. The pistons mounted within the driving and feed chambers are connected to a shaft (11) which carries an enlargement (12) at its lower end. This engages an indexing finger (13) when in the top dead centre position. The engagement causes the rotation of a square section spring biased shaft (14) which causes the pivoting of the flap valves controlling the inlet gas feed.

Description

 The present invention relates to a series of improvements intended for anesthesia respirators and in particular those comprising a distribution chamber for the patient, holding the volume necessary for unit ventilation, said chamber being moved by two other chambers which are linked to it. and which themselves receive the gases at a higher pressure.

 In certain respirators, a membrane is responsible for distributing a defined volume of a gas of defined composition to a patient, the said membrane being pushed by springs or by the action of a gas at a higher pressure in another. e membrane. In these cases the f-equence of the device varies according to the compliance of the device and the patient. However, this drawback, the present invention uses a calibrated valve at the outlet of the chamber. e membrane swept.

It therefore miposes constant pressure, independent of compliance and the volume served, and thus regularizes the speed, which obviously maintains the frequency.

A fact-induced one causes a frequency variation,
When the function of the respirator is provided by two oppelling chambers, when the relaxed gas from these two chambers is then distributed to the patient mixed with another gas, and when the composition of the final gas is defined by the v- '' umes -spectifs of a pa-t of 1a dist-ibutin room to the patient and other by that of the relaxed engine gases. We then play the volume of these relaxed gases to vary the final composition, and for this, the filling pressure of the drive chambers is made to be checked and by doing so nn modifies effort mnteu- and d @ n @ 'at frequency speed. 0the engine effort is caused by the pressure difference between that of the two chambers - receiving the full flow and the other chamber in the evacuation is 1 supply. It is then possible to compensate for the variation in force by acting on the adjustment of the rolling devices until the initial equilibrium is restored.

This can be done advantageously and according to the present invention by mechanically linking the pressure control and that of the rolling mills. Ce'n of course requires an adjustment of the linearity of these commands and also a kinematic connection arrangement such that each command can be,
but that in this case some quotes nevertheless react one
on the other by privileging certain entr @@ ll @ s. An example on such a link is therefore dunné plus l @ in.

 Another improvement consists in the adaptation of a small device, in the case of a respirator using two chambers, the low dead center goes high from the room word-ice of meaning nppnsé to the room p-incipa1e.

 In fact, when the stroke variation of said main chamber is used, which means that the volume of gas distributed during each cycle, the stroke of the two opposite driving chambers varies by the same value , but while on the matrix chamber in the same direction as the main chamber, the variation concerns the race from the dead center thaut (that of zero volume) in 1, aut-e it is the bottom dead center which remains constant that of maximum volume) this chamber goes therefore between two volumes, one of which is the maximum volume instead of va-ie- between a volume -èg'ab'e and a zero volume. Judicious of the cylinder concerned dissociating it from the rest of the device for its application a depreciation of age equal to that of the regulation of the race makes it possible to eliminate this drawback. From then on, if we place the rocking elements of the control valves on the same cylinder, the settings are brought back to a single order.

Finally, 'es-espi-ateu-s above use pa-times a device for dispensing anesthetic in liquid phase of a design such that while being adjustable, it follows
igorously the variations of the other parameters. This device is ^ -organized with the motor source 'e movement of the --espi-ateu-' itself, but i 'can also be provided with an independent control, (electric after example) triggered at each cycle pa - any signal emitted during said cycle and to be used in other models of respi-ateu.

 These various improvements will be better understood by following the diagram I above, which is shown in an example of an embodiment incorporating said improvements.

 We find, as partially in similar respirators, a chamber for feeding the patient (i) and two motor chambers (2) and (3). In Xa chamber (2) the bottom of the cylinder is movable, so that if the stroke varies @@ chambers (2) and (3) have a symmetrical operation.

 The variation mechanism shown here by way of example: 3-pie comprises an auxiliary chamber (4) integral with the bottom of the cylinder (2) and which may or may not be supplied voluntarily.

When it is supplied it raises the bottom of the cylinder (2) and when it is not it falls back to a variable height stop device constituted for example by a rotating cylinder (5), cut into a rack on 2 times 1800 and two pins (6) carried by the cylinder body. The pressure in the chamber (2) being always positive, the cylinder body always tends to descend in abutment. Other mechanical devices achieving the same goal are possible without calling into question the principle of this patent.

A valve (10) is placed on the patient circuit, its control pressure is of the order of 4 to 5 K Pa. Its presence allows to maintain a constant force on the membrane of the chamber (1). Its pressure is higher than the maximum pressure necessary for the patient, but remains compatible with the operation. A quick calculation allows you to check
If a maximum operating pressure of 800 l is allowed; Pa or 500 K Pa absolute, its expansion to around 100 K Pa absolute will occur in a volume ratio of approximately 5 and the stroke of the chambers being the same, the surfaces will be in the ratio of 10 (since there are 2 motor chambers The efforts being in the ratio of the relative pressures we can therefore have on the membrane of the chamber (1) up to 1/10 of the pressure of the driving chambers. The theoretical minimum pressure in said chambers is then 50 K Pa generating a mixture of 30% engine gas and 70% auxiliary gas.

 Diagram 2 represents a mechanical device intended to reproduce the sudden tilting of the control valves. The rod (it) is integral with the pistons of the chambers (1) (2) and (3) and carries at its lower part an index (12) coming into contact with another index (13) when it is in neutral high. This contact causes the rotation of a square rod (1) ul, under the influence of a spring (15) can take two stable positions. the rotation caused by the index (12) then makes it pass from a position A to position B and in this wind movement it causes the valves to tilt and keeps them in their new position. The other tilting, corresponding to the "dead center bs" position is the result of another index (1G) also carried by the rod (12 and cooperating with n index (17) symmetrical with (13) relative to the axis of the rod (18) and adjustable in height by a fork integral with the body of the cylinder (lj) nvi is that regulating the chamber (2). We see that we thus simultaneously adjust the bottom dead center and the correct volume of the chamber (2). Obviously this result can be obtained, if one is in the case of a device having a power supply, by the use of microswitch and solenoid valve.

In diagram 3 is shown a kinematics of combined control of the pressure regulator regulating the pressure in the driving chambers (therefore the title of the mixer distributed) and of flow limiters ensuring the timing. A differential (18) attacks by its two outputs (26) and (27) the control screws of the limiters 24 and 25 respectively regulating the expiration time and the inspiration time. The external cage of said differential is connected to a manual control, locked in the rest position and called "I / E" (.20) -one can imagine that if one operates the one qelconqe of the two differential outputs (18) Its two screws 24 and 25 will be entralnôes in synchronism in a certain sense, and that if we unlock and operate the control (20) we will impose a difference on the same two screws. The output (26) of the differential (18) is on the other hand connected to the output (28) of a second differential (19) whose other output (29) controls the pressure reducer (23) itself. manual blocked in rest is linked to the output (29) and is called "mixture title" and a last manual control (21) also blocked in rest controls the external cage of the frequency differential (19). Under these conditions, an order by (21) will cause the cage (19), the exit (28) (since 29 is blocked by 22) and therefore the exits (26) and (27) of (18 so the duration is well controlled of the cycle by simultaneously controlling (24) and (25 3. A command by 22 will synchronously trigger the expansion valve (23) and the limiters (24) and
(25). it will therefore correct the cycle times at the same time as it will modify the pressure of the working chambers.

We therefore performed a command of the 3 parameters I / E ratio, cycle time, titer of gas in which each
command affects only one of the parameters while correcting
other settings if necessary. However, it should be noted that
the adjustment of the I / E ratio is carried out preferably first
Location.

flans' e case where the 7th respirator has a surge of electrical energy, it is obvious that all these adjustments can be produced by motors asse-vis, the bases of control being then
For I + E (cycle time) and I / E 1a measurement of these flag values and their comparison with the displayed values, then the command to cancel the deviation in the next cycle.

 Or, knowing the stroke and its value I and E, calculating the resulting speed of movement and its comparison with the actual speed of the mobile crew.

 For the 7th title of the mixture, the measurement of the depression, in each room, its conversion into a resultant title, its comparison with the displayed value and the command to cancel the deviation.

 Pou- the volume per cycle, 7a metu-e of 1a cnu-se and its enhancement requested by the use of a motor device that @ conch, for example an electric actuator.

 All of this requires the use of displacement, velocity, pressure, time displacement sensors, etc., all of these perfectly known elements, and the development of instructions after a cal cu 'ateu- sufficiently palatable, which is the case. perfectly known equipment built around microprocessors.

 The diagram 4 relates to the dist-ibutinn device for anesthesia in the liquid phase with piston maneuvered by the chamber movement. A quick calculation firstly allows you to size the pump you need.

t : 9,52 mm et de 26,45 pnu- une tige de = 3 mm. Cette quantité d'anesté- sique est dans les équipements actue's èvaporée par lècharge en surface de 5 à 10 % du gaz envoyé au patient.Selon le procèdé proposé pa- 'e prôsent Brevet, 'e volume de gaz destiné a cette évaporation va-ie de 30 à 100 % et t-ave-se une paroi poreuse imbibée de liquide, au 7ieu d'en 'èche- la su-face. L'évaporation çst donc suffisante gnu, qu'à chaque cyc' e , 7a -quantit: injectée dans ladite paroi poreuse soit évaporée de façon certaine.The molecular mass of fluorethane (CF 3 - CH C1 -B-) is 197.4 or, in the gaseous state for 15, 8.81 gr / dm3. your density of the liquid being of the order of 1.87 we find, for a tidal volume 1.5 and a volume concentration of 4%, a mass required for each cycle of 1.5 X 0.4 X 8.81 = 0.35 g - i.e. a liquid volume of 0.35 = 0.187 cm3 which gives for
1.87 a piston rod of e = 5 mm a stroke of

t: 9.52 mm and 26.45 without a rod of = 3 mm. This amount of anesthetic is in the current equipment evaporated by the surface loading of 5 to 10% of the gas sent to the patient. According to the process proposed by the patent, the volume of gas intended for this evaporation will ie from 30 to 100% and t-ave-se a porous wall soaked with liquid, the 7ieu en 'èche-la su-face. Evaporation is therefore sufficient gnu, that at each cycle, 7a -quantit: injected into said porous wall is evaporated in a certain manner.

In said diagram 4 we can see the tank (30), the stop valve (31), the pump itself (31), the non-return valve (33), the injection valve 1 34) which is provided of a calibration spring and is placed immediately before entering the porous wall (35), this in order to correctly dose the small quantity delivered during each cycle. The control of the piston rod (32) can be done first as the
Main patent and its additive by taking the movement, in a variable ratio on the rod carrying the motor and debit chambers of the respirator, but it is also possible, when one wants to use such a device in a model of respirator having a source of electrical energy to use a device such as the one shown in diagram 4 and comprising an electromagnet (36) whose arù: movable ature (37) is linked to the piston rod (32). It is obvious that an electrical impulse, with each cycle will propel the quantity thus predetermined
Other mechanical devices can be used without calling into question the principle of this patent.

 As for the previously mentioned parameters (I + E, I / E), volume, title) the amount of dis anric anesthetic can be controlled by looping on the display.

 Diagram 5 is another possible version of the device represented by diagram 1 using membranes in place of the seals and another arrangement making it possible to reduce the size of the device. There is the main membrane 39, and the driving membranes 40 and 41, the piston 42 supporting the membrane 39 is extended into a cylinder in which are the membranes 40 and 41 which therefore operate with a movable cylinder and fixed pistons. Said cylinder having a mid-bottom separating the two membranes.

 The unit volume adjustment is then obtained by varying the position of the lower piston 43 using, for example, a screw controlled synchronously with the device intended to control the tilting of the valves. One of the advantages particular to this construction is the possibility of accommodating inside the volume 44 all of the control and regulating organs of the apparatus, this would leave to the series only the variable capacity or bellows intended for allow you to see the operation of the device, where the sources of compressed gas and the anesthetic tank, all for safety reasons.

 Diagram 6 represents another possible assembly for the kinematics represented in diagram 3 and adapted more particularly to the case or one wishes to use two different gases to supply each of the two driving membranes. In this case, intended more particularly for anesthesia, if the variation in composition of the gases is obtained by variation of the pressure in said motor chambers, we therefore again find ourselves with the problem of regulating speed and cycle time .

Two separate regulators (49 - 50) are used and their joint control varies them in reverse; their average pressure being substantially constant. Their command 47 (called "title") is linked to the differential cage 44. One of the outputs of this differential is linked to the command 46 (I / E) and the other to the differential cage 45. The two outputs of the differential 45 are linked to flow limiters 51 and 52 and one of them carries the 48 "frequency" control. All these commands are blocked at rest.

 We therefore see that an action on 47 will drive the two regulators in opposite directions and will correct the correlative variation of I / E, that a command by 46 will vary in opposite directions the two flow limiters without affecting the title and that finally a command pat 48, by varying in the same direction the two limiters will bring an adjustment of the frequency.

 Finally, diagram 7 represents a possibility of refining these adjustments by balancing the I / E command. In fact, in the devices shown on diagrams 3 and 6, the I / E command only intervenes on, one / two. limiters, the other remaining fixed. To balance this control, the present invention proposes to use a particular version of the differential 45 (or 18) in which the two outputs are linked by friction.

In diagram 7 we therefore see a differential, the cage 53 of which is linked as before to a command 59 going towards
I / E but whose satellites 54 and 55 are mounted on two half-axes leaving a passage to allow friction 58 to be placed between the two outputs 56 and 57. The command 60 (frequency) is no longer blocked at rest, but free. When we order by 59 (I / E) the presence of friction means that we will enter in the same direction and at the same speed the two outputs 56 and 51 therefore, of the same value and in the opposite direction the limiters 61 and 62. On the other hand, a command by 60 (frequency), will give an equal and opposite movement to the two outputs 56 and 57, since the cage 53 is blocked and the friction slips. This will result in an equal variation and the same direction on the two flow limiters.

Claims (9)

- CLAIMS  1) Automatic ventilator comprising two motor chambers and a third chamber for distension of tension gas and characterized by the presence, su- 'e baked of the third chamber used in insufflatinn, of a calibrated valve whose setting pressure is of the same order of magnitude as the maximum pressure admissible by the patient, and placed between the outlet of said chamber and the patient.  2) Automatic respirator according to claim 1a and ca-acté-ized pa- a permanent kinematic connection between the 1st or pressure regulators supplying opposing chambers, and the flow regulators generating the rolling of the circuit of said chambers.  3) Automatic respirator according to 'has claim 2 and characterized in that 1a kinematic connection pe-manente is the fact of a differential whose two outputs are connected to the control screws of regulators with a ratio of (- I) while naked' the cage of said regulator is connected to a manual control blocked at rest and that one of the two outputs of the differential is wired to an output of a second differential whose ra second output is' linked to the regulator and to a manual control blocked at rest, which also makes it possible to have 3 separate controls on 3 separate pa-amets, the mutual effects of which are minimal.  4) Automatic respirator sleon claim 3 and ca-acté-ized in that at least one of the differentials has an inte-ne or exte-ne friction realizing its two half-a-b-es output.  5) Automatic respirator according to a claim 1 and characterized in that the actuation of the control valves of the supply circuit is made therein highly adjustable with '' a cleat driven by 'e movement of' 'axis carrying the members which leads to a proportional adjustment of the Sénèré volume by each of them.  6) Automatic ventilator according to 'has claim 5 and ca-acté-ized pa-' e fact that 'e cylinder of ce''e chamb-es in opposition which is mounted to' 'inve-se de' a 30 chamb- e is -èg'ab'e according to the location of displacement of said rooms.  7) Automatic respirator according to 'a-claim 5 and 6 characterized in that the movable cylinder supports and moves, vec' ui 'are adjusting the stroke of 1 axis carrying ls membranes.  8) An automatic respirator according to claim 1 and characterized by the presence of at least one piston in place of at least one of the membranes.  9) Automatic respirator in which the anesthetic is dispensed in the liquid phase by a volumetric dosing pump controlled by a source of energy external to the direct operation of the respirator.