DE2045494A1 - Pneumatic control device for a ventilator - Google Patents

Description

ν * · «Munich, den

2ö9, Γ 2 (J θα

ΡΪΈ LIMITED, Cambridge, Great Britain

Pneumatic control device for a '" Ventilator

The invention relates to a pneumatic control device for a cyclically operated medical ventilator.

In ventilators for assisting breathing or for use in anesthesia, the duration of the inhalation and exhalation periods can be controlled by inhalation and exhalation valves, which are set either after a preset (| time or by a specific pressure or volume value of the to or from ventilators are known in which the inhalation and exhalation periods can be optionally controlled depending on at least two of these parameters. An electrical control device is provided for such a ventilator (German patent application P 15 66 675.8). When operating the same, sparks may form, which in return

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look to certain flammable anesthetic gases Can lead to complications.

The object of the invention is to completely eliminate this source of danger by dispensing with the use of electricity and to provide an exclusively pneumatically controlled ventilator in which the inhalation and exhalation periods can optionally be determined by one of several of the parameters mentioned above.

Such a pneumatic control device for a ventilator that can optionally be controlled as a function of various parameters is characterized according to the invention by a switch-over slide which at least connects to the breathing control valve via a gas line communicates to reverse this at the end of each inhalation and exhalation period, at least two optional active slide switch in the gas flow of the switch slide, each of which responds to a different one of the parameters time, pressure or volume of the gas flowing to the patient, and one Switch selector for selecting the currently active switch slide.

In the simplest case, the switchover slide is only used for control of the inhalation control valve. The inhalation period becomes either according to a selected parameter or according to the first occurring condition in the case of two or more selected parameters. In the latter case, the breathing period is ended when the first selected switching

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valve responds. Since this already causes the switch is actuated, has the subsequent actuation of a second Switching valve in .this period none. SinfIuP. The Ausatn-yrigseason can be controlled in a known manner by the passage of time will.

However, the end of the disengagement period is also preferred optional-controlled by various parameters. To this j |

Purpose is also the Ausatmungssteuervenl.il connected to the ^{> r "Tm.schaltschieb er.}

In this case, two groups of slide switches are preferably provided, one of which actuates the switch slide at the end of the inhalation periods and the other at the end of the exhalation periods. As a result, both periods can be controlled independently of one another by any parameter or a combination thereof. Each of these groups preferably comprises three slide valves for time lapse, gas pressure and gas volume.

The UmscualLschdeber controls the sin and exhalation valves of the ventilator, preferably indirectly via another switchover slide. This allows in the relatively short Quickly insert the pipelines between the two changeover valves constant air pressure can be built up, regardless of the Pressure ratios at the outlet of the second switchover slide.

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Below is eir. Embodiment of the invention Hand outlined drawing. Here are:

1 shows the schematic representation of the pneumatic control device
and

Fig. 2 shows a ventilator, which with the control device according to φ Fig. 1 is connected.

In the pneumatic control device according to FIG. 1, air is supplied under constant pressure of, for. B. 4 at from a pressurized gas source 8 (e.g. a compressed air cylinder with pressure regulator) via a Line 11 a manually operated slide 10, which is used for and switching off is supplied. The slide 10 is shown in the "off" position. Will the control piston to the left shifted, the compressed air reaches the main inlet via a line 12 which was previously connected to the outside air

a commercially available switchover slide 13 with five inlet and outlet openings. In the position shown, this switchover slide 13 directs the air pressure to a LeLt. xr ^ j 1 '., the. ι i L of the control opening 15 of a second switchover slide 16 is connected so that it is held in the position shown. A line 17 connects the line 12 to the main inlet 19 of the second switchover slide 16, so that in the position shown a line 20 is supplied with compressed air. In the other position of the switchover slide 13, the line 14 is connected to the outside air via an opening 21

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and a second Leitimg 22, which previously has an opening was in connection with the outside call, compressed air is now applied, so that the air pressure on another control opening 24 of the slide 16 arrives. Since the line 14 is vented is, the control piston of the slide 16 moves into its left position, in which the line 20 via an opening 25 comes into contact with the outside air, while a line 26, which previously vented through an opening 9 of the slide 16 " was, is pressurized. The additional switching slide 16 supports the rapid build-up of a constant Air pressure in lines 14 and 22 regardless of the manner in which the pressure in lines 20 and 26 is used.

The switchover slide 13 is also actuated by means of two control openings 27 and 28. A given to the control port 27 of air pressure causes the slide occupies the position shown ä position, while a given on the opening 28 air pressure .the slide converted into the other layer, if each non-pressurized control port allows the completion of the trapped air.

The UmschaItschieber 13 and 16 do not need a constant supply of compressed air to stay in a certain position; a pressure pulse is sufficient to bring them into a certain position to transfer, in which they remain until the arrival of the next pressure pulse at the other control opening.

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The control openings 27 and 28 are subjected to air pressure via control lines 29 and 30. This is done as follows: The pressure from the line 26 goes via a line 31 to three selector slides 32, 33 and 34, shown in their rest position, for the selection of the inhalation mode and from there via associated switch slides 35, 36 and 37 to the control line 29 Air pressure from line 20 via line 38 to selector slides 39, 40 and 41 for exhalation and from there via associated slide switches 42 to 44 to control line 30. All selector and slide switches are shown in the switched off or inactivated position.

The slide switch 3 5 actuated by the inhalation pressure opens when a membrane 45 of a pressure cell 46 moves outward, which is connected to the breathing circuit of the ventilator via a line 47. The switch that depends on the exhalation pressure 42 is also by inward movement of a diaphragm 48 a The suction cell 49 is actuated, which is connected to the breathing circuit of the ventilator via a line 50.

The switch slide 36, which is dependent on the gas volume of inhalation, is activated by downward movement of the end 51 of a one-armed lever 52 opened under control of the volume of gas flowing to the patient. Likewise, the one dependent on the timing of svo Ium en opens Slide switch 43 upon upward movement of the end 53 of a one-armed lever 54, which is exhaled by a patient Gas volume is controlled.

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The actuation and opening of the time-dependent slide switch 37 and 44, which * are designed as differential pressure switches, depends on the elapsed time. These two slide switches are constructed in the same way, but receive theirs Operating pressure of different points of the pneumatic Circle. The high pressure side of the slide switch 37 is connected to the line 31 and its low pressure side is connected to a line

54 connected, which leads to line 22. In contrast, the (J high-pressure side of the slide valve & Ά is connected to line 38, while its low-pressure side is connected via a line

55 is in communication with the line 14. Instead, the high pressure sides of the slide switch 37 and 44 can also be _{fed by a constant pressure f,} that is to say the lines 11, 12 or 17. On the low-pressure sides of the switches 37 and 44 there are members 75 and 76, which throttle the inflow of air (-ζ. B. needle valves), but allow the rapid air outflow from the low-pressure side of the switch slide (z. B. check valves connected in parallel ). Furthermore, adjustable volume cylinders 56, 57 are connected to the low pressure side of the time switches 37 and 44. The effective capacity of the cylinders 56, 57 can be adjusted by moving the pistons 58. For this purpose, their screw-threaded piston rods 59 are moved with the aid of rotary knobs 60. Thus, the delay between the action of pressure on the low-pressure side of the slide switch 37 and 44 and the response of the same can be changed,

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The selector slides 32 to 34, 39 to 41 and the actuating slide 10 are weak in FIG The switch-off direction is loaded and operated by hand. This manual operation can be achieved by converting the small facilitate linear displacement in a rotary motion. An only slightly out of round cam disk is used for this. the Slide switches are arranged along a camshaft 61,. so that by rotating the same actuated the slide and the mode of operation each period of the ventilator can be selected. This is done by turning a single knob 62.

In Fig. 1, for the sake of clarity, the movement of the membranes 45 and 48 of the load cells 46 and 49 is shown as whether they operate the slide switches 35 and 42 directly. In reality this movement needs to be strengthened; This can done either pneumatically or mechanically or by a combination of both measures. The prescribed Pressure values at which the slide switches 35 and 42 respond can be adjusted by changing the pneumatic amplification and / or displacement of the fulcrum of a lever that leads to the linkage between the membrane and its slide switch heard, change. Instead, the load cells can also be moved relative to the linkage.

In the case of the slide valves 36 and 43 controlled by the gas volume, the lines between these slide valves and the assigned

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th selector slide in 33 and 40, as well as between the slides 36 and 43 and the control lines 29 and 30 are flexible. The slide switches 36 and 43 and the associated levers 52 and 54 are located on moving hats that were interrupted by Lines 63 are indicated. The location of the levers relative to a

B active

The push rod, which goes up on exhalation and down on inhalation, can be adjusted to determine the size of the gas volume, in which the direction of movement of the push rod is reversed by actuating one of the two switch slides 36, 43 . ·

Check valves 64 and 65 preloaded with very weak springs are located between line 31 and control opening or line 38 and control opening 28 of switchover slide 13 so that, for. B. at pressure on the line 31, the check valve 64 is closed, while after venting the line 31 via the line 26, the pressure from the control line 29 and the ^ control port 27 via the check valve 64 and the vent 9 of the Urnschaltschieber 16 can be reduced. The control opening 28 is also vented via check valve 65, lines 38 and 2, 0 and opening 25 of the switchover slide 16.

If the differential pressure slide valves 37 and 4A have open vent openings 66, check valves 67 and 68 must be included in the control lines 29 and 30 in order to prevent pressure loss from a control line via an unaffected

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to prevent activated time switch. £ ind the openings 66 closed, so the check valves. 67 and 68 can be omitted.

Lines 20 and 26 are connected to the inhalation and exhalation control valves of the ventilator and the alternating one Pressure build-up in these lines controls the cycle of the ventilator, as described later with reference to FIG will. First, however, the mode of operation of the pneumatic control device shown in FIG. 1 will be described. First of all, it is assumed that the selector slides 41 and 41 are open and the other selector slides are closed.

Is the main slide 10 open and the switchover slide in the position shown, the slide is also located. 16 in the position shown and the air lines 14 and are under pressure.

The compressed air goes from the compressed air source 8 via line 11, main slide 10 and changeover slide 13 in line 14 and from there via line 55 and let throttle point 76 in the cylinder 57 of the time switch slide 44. The pressure in this cylinder increases gradually at a speed that from Cylinder volume and the throttle cross-section depends. Furthermore, the compressed air reaches the line 38 from the compressed air source 8 via line 17 and switching valve 16 and produces a counter pressure against the differential piston 69 of the slide switch

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for the exhalation time. The piston is connected to the larger piston 70, so that after the pressure build-up in the cylinder 57 to a value that depends on the cross-sectional ratio of the pistons 69 and 70, the switch slide 44 becomes active and the compressed air from the line 38 via the open Vählschieber 41 and the slide 44 enters the control line 30 for the switching slide 1.3. As a result, the control piston 71, which has a switching element 12 between two thrust pistons 73 and 74, is shifted to the left in -Fij, 1. The air on the left-hand side of the thrust piston 73 is driven out via Oef f nur.g 27, Äiickschlagvei-til 64, line 31 and Oeffmine '9 of the slide 16.

As soon as the control piston 71 has switched , the compressed air goes from the compressed air source 8 via the switch 13 into the line 22 to actuate the switchover slide 16 which is exactly the same as the slide 13 is constructed . Dai-> i, the compressed air can get from the compressed air source 8 via line 17 and slide 16 into the line 26, while the line 20 is vented via the opening 25.

Furthermore, the compressed air now comes from the line 22 via the Line 54 and the Di ^ osselstelle 75 on the Niederdrujcseite of the switch slide 37 for the inhalation time into the cylinder 56 with adjustable volume.

The slide switch 37 works in the same way as the Slide switch 44. If, after the set delay

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time responds, nozzle 3as flows from the compressed air source S via line 17, changeover slide 16 and line? 6, then via Leitn.j 31, Tählschieber 34, bchaltschieber 37, check valve 57 and control line ? -_ 3 to the control opening 27 of the Unischaltschieber 13, see above that its control piston 71 is again shifted to the right in FIG. The compressed gas located on the right side of the thrust piston 74 reaches the outside via opening 2B, check valve 65, line 38 and opening 9 of the switching valve 26. This displacement of the control piston 71 then causes the switchover slide 16 to move into the right-hand position of FIG. 1, the opening 24 being vented via line 22 and opening 23 of the switchover slide 13. The sequence described above is then repeated so that the pneumatic control device continues to operate in accordance with the set delay periods.

If one of the other selector slides 32, 33, 39 or 40 at the same time with the selector slide 34 and 41 or instead of the same is open, causes the actuation of the associated slide switch 35, 36, 42 or 43 a gas flow from the line 31 to the control line 29 or from the line 38 to the control line 30, so as to operate the switchover slide 13, whereupon the switchover slide 16 immediately thereafter does the same Movement.

The lines used to control the ventilator and 26 become so in accordance with the operation of the dials

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alternating, pressurized and connected to the outside air. So that the pneumatic control device can work, ■■ "" .. • muli at least one of the selector slides 32 to 34 and 39 to 41 be open. If more than one selector slide is open, it controls the first responsive selector slide. the switchover of the switchover slide 13 and thus the termination of an entry or Ventilator exhalation period.

■■ '■ \, ■ ■; -. i The pneumatic control device described can be used together with any pneumatically controlled ventilator. Fig. 2 shows an example of a closed circuit.

Three bellows 80, 81 and 82 are attached on the one hand to a fixed support 8 3 and on the other hand connected to a common actuating rod 84 which carries a weight 85 for compressing the bellows 80, 81 and 8 2. The lines 20g and 26 from the control device of FIG. 1 go to an inhalation control valve 86 and an exhalation control valve 87. These control valves are opened by springs as long as there is no pressure on the corresponding control lines 20 and 26.

A drive gas comes through a line 88 and a check valve 89 into the bellows 80. The drive gas can, for. B. compressed air from the compressed air bottle 8 in FIG. In the exhalation period, the line 20 is under pressure, so that the control valve 86 is closed and a line 90 blocks that with the

Outlet opening of the bellows 80 is connected. This stretches as a result. The expansion is via the operating rod 64 on the suction bellows R1 and on the third bellows 82. On the other hand, the exhalation control valve 87 is open, because the control line 26 is not under 'pressure. As a result, ventilation gas flows from the patient via line 31, a check valve 92, line 93, control valve 87 and line

^ 94 in the suction bellows 81. The outflow opening of the bellows 81 is blocked by a check valve 95. The ventilation gas from the patient, who is fed to a line 96 at very low pressure, first passes through a gas cleaner 98 into a storage bag 97 with flexible walls; during the Exhalation, this gas flows from the bag 97 via a check valve 99 into the expanding bellows 82, while a Check valve 100 in the outlet opening of this bellows prevents gas from entering at this point. The connection

~ between the outlet opening of the bellows 8 2 and the patient

goes via a line 101, a flow regulator IO2, a Line 103, a diaphragm valve 104 and a line 105 to the patient's breathing mask.

The flow regulator 102 consists of a cylinder 108 into which the gas flows from the bellows 82 through the line 101. When flowing out into the line 103, the gas must flow through one or more holes 109 of different diameters in the wall of the cylinder 108. By rotating a shaft 110, the

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Cylinder 103 rotate, increasing the number and size of the front the "outlet soff nu-n.g of the flow regulator 102 is located Holes 109 and: 1a π it the flow rate can be adjusted.

In the liinatmuicgsperiode- the Jruckve.rhältni are sse to the '.- Steuerlei obligations 20 and 2 6 reversed so that now valve? 6 ■ open and valve closed 87th Through the opening \ valve 8-6, the gas pressure in the bellows 80 may drop and the weight- BfS. presses the three bellows together. The gas In-Ba-Ig 81 flows via the non-return valve 95 to the line 36 and from there passes again via the gas cleaner 93 into the storage bag 97. At the same time, the gas in the bellows 82 passes via the non-return valve 100, line 101, flow regulator 102 ', line 103, diaphragm valve 104 and line IC? in the patient line to the patient's lungs. ventilate. Since this ventilation pressure is greater than that required to fill the storage bag 97, the non-return valve 99 remains closed so that no direct gas transfer from the bellows 81 to the bellows 82 can occur and the gas flowing back from the patient twice, namely when filling and emptying the bag 97 through which the gas cleaner 98 flows. As is normal when working with a closed circuit , the gas supply connected to the sn -lie line 96, after the device is initially filled, only serves to prevent losses due to leaks and / or absorption by the patient to replace..

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The line 9β is connected to the bellows ^Ρ via a 7> pressure control valve (not shown) and a non-return valve in a third inlet and outlet opening of the bellows 81, so that some breathing gas from the bag 97 into the bellows 81 during the Aasat.nunj can reach to regulate the developed suction.

The bottom XX. and the upper side YY of the actuating rod 34 actuate the levers 52 or: A of the volume switching slide 36 and 43. The lines 106 and 1C7 branching off from the line 105 are connected to the lines 47 and 5 C of the pressure and suction cells 46 and 43, respectively.

The check valve 32 prevents gas from flowing from the bellows 81 to the patient if the patient attempts to inhale during an exhalation period. As a result, a speed which is sufficient to respond to the measuring cell 49 is reached more quickly than to whom; the check valve ^c > 2 would be left. The check valve 92 can, however, instead be arranged in the inlet opening of the bellows 81, which is connected to the line ? .A .

Fig. 2 shows only the main parts of the ventilator. Safety valves, Measuring devices, etc. are omitted.

The pneumatic Cttv ex device according to Fig. 1 can together with the control valves 86 and 87 in Fig. 2 for actuating any other pneumatically controlled ventilator is known Type with manually operated), open or closed circuit be used.

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Depending on the volume of the air enclosed in certain lines of the control device, which in turn depends on the length and cross section of these lines or the physical arrangement of the various control spools and on the available pressure required in the control lines 20 and 26, the switchover slide 16 can be omitted, so that the line 14 is then directly connected to the line 20 and the line 22 is directly connected to the line 26. λ

It is conceivable that the UmschäItschieber 13 and 16 stop by Falschbedienurg the pressure source in a central position, 12 and 17 in which they block the lines, so that the control piston 71 can not be moved more. In order to ngreifen.zu egg here, a switching device may be provided which einen.Druck directly from the line 12 on one of; are control inlets 27 and 28th This switching device can be provided either for manual actuation or is mechanically connected to the main slide 10 in order to give an automatic pressure pulse to one of the control inlets when it is switched on.

BAD ORiQWAL

Claims (12)

t r Munich, Austria P PP 9, FYE LIMITED, Cambridge, UK η s ρ r ü c η e lj Pneumatic Sieuereinrichtundfür a selectively controllable in dependence on various parameters respirator, characterized by a switching damper (13) of the ventilator is in communication via a gas line (20) at least with the Einatmungssteuerventil (86) to this end of each input and exhalation at least two optionally active slide switches (3 5, 36, 37) in a control line (29) of the slide switch, each of which responds to a different one of the parameters time, pressure or volume of the gas flowing to the patient, and a switch selector (^ l) to select the currently active slide switch. 2. Control device according to claim 1, characterized in that the exhalation control valve (87) is connected via a control line (26) to the switch slide (13) and that there is at least two optionally active slide switches in a second control line (30) for the switch slide (42, 43, 44) are located, depending on a different one of the parameters - 2— 10 9 8 13/1211 Time, volumetric flow or volume of the flowing away from the patient Apply the gas and also use the switch selector (6l) are connected. - 3, control device according to claim 2, characterized in that that the e iiclialtschi eber in two groups ai. are ordered by one of which is used to actuate the switching valve (13) at «. The end of the inhalation period and the other to actuate the Switching valve at the end of the exhalation period. - (J 4. Control device according to claim 3, characterized in that, that each switch valve group consists of three switch slides, of which the first "(35, 42} on the print, the second (36, 43) on the volume of the zimbzw. flowing gas from the patient and the third (37, 44) on the expiry of a set Duration responds. 5 «control device according to claim 4, characterized in that that the three switch slides of a group are parallel to each other between a control inlet (27, 28) of the changeover slide and a pressurized gas source (31, 38) controlled by the same lie. 6. Control device according to one of claims 2 to 4, characterized characterized in that the UmschaItschieber (13) has a control piston (71), which, depending on the 1098 11/1711 2045A9A counteracting tax decrees (27, 28), the prevailing gas pressure is displaceable and, depending on its position, a Hauptteirlaf * (13) from a pressure source (8 ) connects to one of two outlets (14, 22) , and that each of these two outlets either directly or indirectly with the inputs and. Ausatrramgssteuerventilen ϊπ connection and is also connected via a group of parallel slide with a ¹ control inlet of the switching slide (13), so that the two slide groups alternately control the gas flow to the two control decrees. 7. Control device according to claim 6, characterized in that the control piston (7l) of the non-switching slide is an between two actuating pistons (73, 74) located locking member (7-2) on v / eist, which can be displaced on both sides of the main inlet (18), so that it can be connected to one or the other, as the case may be Outlet connects, and that two Entlüf processing outlets (21, 23) controlled by the movement of the actuating piston (73, 74) will. 8. Control device according to claim 6 or 7, characterized in that that each control inlet of the switching slide (13) via a check valve (67, 68) with a lockable Outlet (66) is connected to the atmosphere. -4- 1 0 9R13 Μ? 11 BATH ORIGINAL ■. . £ ■■■ '■ ·. - 9. Control device "according to one of claims 2 to 8, characterized through, a second switch slide (16), the actuating inlets (l5, 24) with the outlets of the first switching slide (13) "are connected and its Outlets (20, 26) with the inhalation control valve (86) or the exhalation control valve (87) of the ventilator in connection stand. 10. Control device according to one of the preceding claims with at least one time-dependent switch slide, thereby characterized in that the time-dependent slide switch (37, 44) is designed as an adjustable pneumatic delay element which has a piston (70) actuated via a throttle opening (75, 76). 11. Control device according to claim 9 and 10, characterized in that that in each case one output of the first switchover slide (13) is connected to an associated delay element (54, 55) and that the outputs of the second switchover slide (16) with actuating lines (31, 38) for the time-dependent Switch slide are connected. 12.- Control device according to one of claims 6 to 8, characterized characterized in that the switch selector (61) on selector slide (32 to 34), (39 to 41) for the individual slide switches (35 to 37, 42 to 44) acts to make the same optionally active close. 1098 13/1211