Controlled opening proportional solenoid valve ventilation unit

Abstract

Title of the invention: Ventilation apparatus with proportional solenoid valve with controlled opening. The invention relates to a ventilation apparatus (1) comprising an internal gas circuit (2) for conveying a gas, and at least one proportional solenoid valve (4, 40, 400) with a gas passage orifice (4.1) with an adjustable degree of opening, arranged on the internal gas circuit (2) and comprising an electrically powered coil (4.2). Electronic control means (5) control the degree of opening of the gas passage orifice (4.1) of the proportional solenoid valve (4, 40, 400) by acting on the electrical current supplied to the coil (4.2) of the proportional solenoid valve (4, 40) so as to deliver a desired gas flow rate or pressure. The electronic control means (5) include an electronic circuit (10) configured to adjust the intensity of the electric current supplied to the coil (4.2) according to a pre-set voltage setpoint (Vset).Figure from the summary: Figure 2.

Description

Title of the invention: Ventilation device with proportional solenoid valve and controlled opening

[0001] The invention relates to a ventilation device comprising one or more proportional solenoid valves whose opening is controlled by means of a particular electronic circuit allowing the intensity of the electric current supplied to the coil of the proportional solenoid valve(s) to be adjusted according to a voltage setpoint.

[0002] In medical ventilation devices, also called artificial respirators or medical ventilators, one or more proportional solenoid valves are used to control, i.e. regulate or adjust, the pressures and / or gas flow rates within the device.

[0003] To do this, the degree of opening (i.e. diameter, size or dimensions) of the gas passage orifice (i.e. calibrated orifice) of the proportional solenoid valve is varied proportionally according to the desired pressure or flow rate.

[0004] In order to be able to modify the degree of opening of the orifice, for example its diameter / size, the electric current in the solenoid valve coil is varied by controlling the coil with either variable voltage or fixed voltage with current chopping.

[0005] Otherwise, the control of a proportional solenoid valve (or valves) is usually based on control, by an electronic circuit, of the power supply to its coil with a variable or constant voltage with chopping of the coil current with a pulse-width modulated rectangular signal so as to vary the current sent to the coil and to control the opening of the solenoid valve orifice.

[0006] The disadvantage of these methods of controlling the coil of a proportional solenoid valve is the lack of compensation for the systematic drift of the current (i.e. intensity) set when the coil heats up due to Joule effect and / or due to an increase in ambient temperature.

[0007] Now, any temperature rise in the coil causes an increase in its resistance (R) with a correlated decrease in the current (i.e. intensity I) in the coil (i.e. Ohm's law).

[0008] A consequence of this drift / decrease in current (I) is a drift in the degree of opening of the orifice of the proportional solenoid valve leading to poor regulation of the pressure or flow of the gas passing through this proportional solenoid valve.

[0009] The present invention falls within this context and aims to overcome this problem in order to improve the control of the proportional solenoid valve(s) equipping a ventilation device, i.e. artificial respirator or medical ventilators, so as to provide a more precise pressure or gas flow.

[0010] One solution of the invention relates to a medical ventilation device or ventilator comprising: - an internal gas circuit for delivering a gas to be administered to a patient, - at least one proportional solenoid valve including a passage orifice of gas with adjustable degree of opening, said at least one proportional solenoid valve being arranged on said internal gas circuit and comprising an electrically powered coil and - electronic control means configured to control the degree of opening of the gas passage orifice of said at least one proportional solenoid valve by acting on the electrical current supplied to the coil of said at least one proportional solenoid valve so as to deliver a desired gas flow or pressure.

[0011] Furthermore, in the ventilation device, the electronic control means include an electronic circuit configured to adjust the intensity of the electric current supplied to the coil according to a pre-set voltage setpoint.

[0012] Depending on the embodiment considered, the ventilation device of the invention may comprise one or more of the following features: - it includes a source of gas to be administered to a person, i.e. a patient. - the gas source includes a motorized turbine. - the motorized turbine is controlled by electronic control means, in particular the accelerations and / or braking of the engine. Alternatively, the gas source includes a gas supply via an external pneumatic supply, typically a wall outlet delivering gas from a gas pipeline, such as a hospital network pipeline. In this case, the control means also serve to regulate the flow rate and / or pressure of the gas supplied by the external pneumatic supply by acting on valve means arranged on the gas circuit, typically the inspiratory branch. - the electronic control means include at least one electronic board carrying at least one (microprocessor implementing one or more algorithms. - it includes means of supplying electrical current. The means of supplying electrical power include an internal rechargeable battery and / or means of connection to the mains (110 / 220V), such as electrical cables, electrical plug or other. It includes a peripheral shell or frame. The electronic control means, the solenoid valve(s) and the gas circuit are arranged in the casing of the device. The gas circuit is a single-branch system comprising only an inspiratory branch. Preferably, the gas circuit has two branches, that is to say it includes an inspiratory branch to bring the respiratory gas to the patient and an expiratory branch to evacuate the exhaled gases rich in CO2. It includes a main proportional solenoid valve arranged on the inspiratory branch of the gas circuit. It includes a proportional PEP solenoid valve (i.e. PEP valve) arranged on the expiratory branch of the gas circuit. It includes a secondary proportional solenoid valve arranged on an oxygen supply line to supply additional oxygen which can be added to the airflow from the gas source, typically the turbine, to enrich it with oxygen. The electronic control means are configured to control the degree of opening of the gas passage orifice of the main proportional solenoid valve, the PEP proportional solenoid valve and / or the secondary proportional solenoid valve. The electronic control means are configured to control the degree of opening of the gas passage orifice by regulating the current in the coil of the main proportional solenoid valve, the PEP proportional solenoid valve and / or the secondary proportional solenoid valve. a shunt resistor is arranged in the electronic circuit, downstream of the coil, so as to be able to measure. the electronic circuit includes a first and a second resistor arranged downstream of the coil and / or the shunt resistor. The first and second resistors are configured to combine a voltage Vs of the current across the shunt resistor with a setpoint voltage (Vset) and obtain a combined voltage (Vfb) feeding a feedback input of the DC / DC converter. The gas circuit may also include pressure and / or flow sensors cooperating with the control means to regulate the gas supply, including the control of the gas source. - the gas circuit supplies a patient breathing interface, such as a breathing mask, providing breathing gas to the patient's airways. - the device's gas circuit is connected to the patient's breathing interface by one or more flexible hoses.

[0013] The invention will now be better understood with reference to the following detailed description, given by way of illustration but not limitation, with reference to the accompanying figures, among which:

[0014] [Fig-1] is a schematic diagram of an embodiment of a respiratory assistance device according to the invention.

[0015] [Fig.2] schematically illustrates an embodiment of the control loop enabling the control of the current of the solenoid valve coil of a respiratory assistance device according to the invention, such as that of [Fig.1].

[0016] [Fig.1] schematically illustrates an embodiment of a respiratory assistance device 1 according to the invention comprising an external shell 1.1, in which are arranged the components enabling the proper functioning of the device 1, when it is used to supply a respiratory gas (i.e. gas with one or more constituents), such as air, oxygen, an air / oxygen mixture or another gas, to a patient.

[0017] Thus, the device 1 includes an internal gas circuit 2, namely one or more gas conduits or passages, for conveying the gas to be administered to a patient P by means of a patient breathing interface, such as a breathing mask 7 or similar.

[0018] The gas circuit 2 of the device 1 is connected to the patient breathing interface 7 by one or more flexible hoses 8.

[0019] The internal gas circuit 2 is here double-branch, that is to say it includes an inspiratory branch 2.1 used to deliver the gas to the patient and an expiratory branch 2.2 used to recover the exhaled gases rich in CO2. However, a single-branch internal gas circuit 2 is also conceivable.

[0020] The expiratory branch 2.2 allows the CO2-rich exhaled gases to be expelled to the atmosphere via an outlet 41 that communicates fluidly with the ambient atmosphere. The expiratory branch 2.2 also includes a PEEP valve 40 for adjusting the expiratory pressure (PEP = positive expiratory pressure). The PEEP valve 40 may be a proportional solenoid valve.

[0021] The gas, in this case air, is supplied to the gas circuit 2 by a gas source 3, namely a motorized turbine 3.1 (also called a (micro)blower, pump, compressor, or similar), that is, equipped with an electric motor 3.2 arranged in a protective housing 3.4, which is surmounted by a volute 3.3 in which a vane (not visible) is driven in rotation by the shaft of the motor 3.2 during its operation. Air is drawn in by the turbine 3.1 and enters through an air inlet 3.5 and exits through an outlet 3.6 in fluidic communication with the gas circuit 2.

[0022] However, according to another embodiment, the gas source 3 could be a pneumatic gas source (not shown), namely a wall outlet supplying the gas, which would be connected to a gas supply line, such as a hospital network. In this case, the internal circuit 2 of the device 1 would be equipped with control means with controlled valve(s), as explained below.

[0023] Optionally, the device 1 may also include an oxygen supply line 401 for adding oxygen to the air drawn in by the turbine 3.1. This addition of oxygen can be made upstream or downstream (see [Fig. 1]) of the turbine 3.1, depending on the embodiment chosen, preferably upstream of the turbine 3.1 so that an air / oxygen mixture enters the volute 3.3 and is then sent to the patient via the gas circuit 2. The oxygen comes from an external oxygen source 402, such as a gas cylinder or a wall outlet supplying oxygen delivered to the wall outlet via a gas pipeline, such as a hospital network. In this case, the oxygen supply line is generally equipped with a control valve, typically a secondary proportional solenoid valve 400.

[0024] Furthermore, as illustrated in [Fig. 1], the internal gas circuit 2, in particular the inspiratory branch 2.1, comprises (at least) a main proportional solenoid valve 4 including a gas passage orifice 4.1 with an adjustable degree of opening, i.e., with a variable and modifiable gas passage cross-section, and an electrically powered coil 4.2. The proportional solenoid valve 4 allows control of the pressure and / or flow rate of the gas passing through it towards the patient P (direction of gas flow indicated schematically by black arrows).

[0025] It should be noted that the other proportional solenoid valves 4, 40, 400, namely valve 40 used for PEEP control and valve 400 controlling the supplemental oxygen supply, can have the same configuration and operation as the main proportional solenoid valve 4 arranged on the inspiratory limb 2.1, namely an adjustable opening degree and an electrically powered coil. They are also controlled by the electronic control means 5 of the device 1.

[0026] Indeed, the device 1 also includes electronic control means 5 comprising at least one microprocessor 5.1, such as a microcontroller, arranged on an electronic card 5.2 and implementing one or more control algorithms... The control means 5 make it possible in particular to control (5.3) the operation of the turbine 2, typically its accelerations and decelerations (i.e. braking) or the openings of the control means with valve(s) or controlled valve(s), in the case of a pneumatic gas source, as mentioned above.

[0027] Generally speaking, electrical power supply means 6 providing the electrical current necessary for the proper functioning of the device 1, in particular for the electronic control means 5. They conventionally include a battery internal rechargeable battery and / or means of connection to mains power (110 / 220V), such as electrical cables, electrical plug or other.

[0028] Of course, the gas circuit 2 may also include pressure and / or flow sensors cooperating with the control means 5 in order to regulate the gas supply, in particular the control of the gas source 3.

[0029] Such an architecture of a respiratory assistance device 1 is generally conventional.

[0030] According to the invention, the electronic control means 5 also allow to command or control the degree of opening of the gas passage orifice 4.1 of all or part of the proportional solenoid valves of the device 1, namely the main proportional solenoid valve 4 arranged on the inspiratory branch 2.1, the proportional PEEP solenoid valve 40 controlling the PEEP arranged on the expiratory branch 2.2 or the secondary proportional solenoid valve 400 arranged on the optional oxygen supply line 401.

[0031] By way of illustration, in the embodiment of [Fig.1], it is considered that the electronic control means 5 control the main proportional solenoid valve 4.

[0032] In this case, the control of the main proportional solenoid valve 4 is done, according to the invention, by acting on the electric current supplied to the coil 4.2 of the proportional solenoid valve 4 so as to deliver a desired gas flow or pressure, including in the event of untimely heating of the coil 4 by joule effect and / or by an increase in ambient temperature causing an increase in resistance R, as explained below in relation to [Fig.2].

[0033] To do this, the control means 5 include an electronic circuit 10 configured to adjust the intensity of the electric current supplied to the coil 4.2 according to a pre-set voltage setpoint.

[0034] [Fig.2] describes an embodiment of such an electronic circuit 10. It comprises a Power supply input 11 downstream of which is arranged a DC / DC voltage converter 12, called a DC / DC converter. Any DC / DC converter available from semiconductor manufacturers can be used.

[0035] The control of the current I in the coil 4.2 of the solenoid valve 4 is achieved through the use of the DC / DC converter 12 which is configured to allow current regulation I instead of voltage regulation.

[0036] The voltage Vout at the output of the DC / DC converter 12 powers the coil 4.2 of the solenoid valve 4 which is arranged downstream of the DC / DC converter 12.

[0037] The intensity of the current I of the current exiting the DC / DC converter 12 and flowing in the coil 4.2 is measured by means of a shunt resistor 13. In other words, the shunt resistor 13 makes it possible to measure the current I passing through the coil 4.2 of the main solenoid valve 4.

[0038] The voltage Vs of the current across the shunt resistor 13 is proportional to the current I in the coil 4.2.

[0039] The electronic circuit 10 also includes a first 14.1 and a second 14.2 resistors, arranged downstream of the shunt resistor 13.

[0040] The voltage Vs of the current is combined with the setpoint voltage (Vset), via the two resistors 14.1,14.2, and a combined voltage, named Vfb, is obtained, which feeds a feedback input 15 of the DC / DC converter 12, allowing the DC / DC converter 12 to adapt its output voltage Vout in order to satisfy the current setpoint (i.e. desired intensity).

[0041] The setpoint voltage (Vset) corresponds to the control voltage of the device's regulation algorithm. It depends on the desired pressure or flow rate, which is set by the user. It is input (at 16) at the first resistor 14.1.

[0042] More specifically, the determination of the setpoint voltage Vset from the desired setpoint current I is carried out as follows within the control means, i.e. microprocessor.

[0043] The current intensity I in coil 4.2 is equal to: I = Vs / Rs

[0044] where: - Vs is the voltage across the shunt terminals 13 - Rs is the resistance value of the shunt resistor 13.

[0045] We then have: Vs = Vfb*(Rl+R2) / Rl - Vset*R2 / Rl

[0046] where: - Vfb is the reference voltage of the internal feedback loop of the DC / DC converter 12 - RI is the resistance value of the first resistor 14.1 - R2 is the resistance value of the second resistor 14.2 - Vset is the setpoint voltage value.

[0047] We then obtain: I = Vfb*(Rl+R2) / (Rl*Rs) - Vset*(R2 / Rl*Rs)

[0048] where I is the desired current to regulate the desired flow rate or pressure.

[0049] Hence: Vset*(R2 / Rl*Rs) = Vfb*(Rl+R2) / (Rl*Rs) -1

[0050] Therefore: Vset = (Vfb*(Rl+R2) / (Rl*Rs) - I) / (R2 / Rl*Rs)

[0051] In other words, the voltage Vset is determined from the desired current I.

[0052] The voltage Vset is then applied to input 16 of the first resistor 14.1, as explained above.

[0053] From this voltage Vset, the control means can then control the circuit 10 to deliver the desired current I used to control the degree of opening of the gas passage orifice 4.1 of said at least one proportional solenoid valve 4.

Claims

Demands

1. Ventilation apparatus (1) comprising: - an internal gas circuit (2) for conveying a gas to be administered to a patient, - at least one proportional solenoid valve (4, 40, 400) comprising a gas passage orifice (4.1) with an adjustable degree of opening, said at least one proportional solenoid valve (4, 40, 400) being arranged on said internal gas circuit (2) and comprising an electrically powered coil (4.2) and - electronic control means (5) configured to control the degree of opening of the gas passage orifice (4.1) of said at least one proportional solenoid valve (4, 40, 400) by acting on the electrical current supplied to the coil (4.2) of said at least one proportional solenoid valve (4, 40) so as to deliver a desired gas flow or pressure, characterized in that the electronic control means (5) comprise an electronic circuit (10) configured to adjust the intensity of the electric current supplied to the coil (4.2) according to a pre-set voltage setpoint (Vset).

2. Device according to claim 1, characterized in that the electronic circuit (10) comprises a DC / DC voltage converter (12).

3. Apparatus according to claim 1, characterized in that it comprises a main proportional solenoid valve (4) arranged on an inspiratory branch (2.1) of the gas circuit (2).

4. Apparatus according to claim 1, characterized in that it comprises a proportional PEP solenoid valve (40) arranged on an expiratory branch (2.2) of the gas circuit (2).

5. Apparatus according to claim 1, characterized in that it comprises a secondary proportional solenoid valve (400) arranged on an oxygen supply line (401).

6. Device according to claims 1 and 3 to 5, characterized in that the electronic control means (5) are configured to control the degree of opening of the gas passage orifice (4.1) of the main proportional solenoid valve (4), the PEP proportional solenoid valve (40) and / or the secondary proportional solenoid valve (400).

7. Device according to claim 6, characterized in that the electronic control means (5) are configured to control the degree of opening of the gas passage orifice (4.1) by regulating the current in the coil (4.2) of the main proportional solenoid valve (4), the PEP proportional solenoid valve (40) and / or the secondary proportional solenoid valve (400).

8. Apparatus according to any one of claims 1 or 7, characterized in that a shunt resistor (13) is arranged in the electronic circuit (10), downstream of the coil (4.2).

9. Device according to claim 8, characterized in that the electronic circuit (10) comprises a first and a second resistor (14.1,14.2) arranged downstream of the coil (4.2) and / or the shunt resistor (13).

10. Device according to claim 9, characterized in that the first and second resistors (14.1,14.2) are configured to combine a voltage Vs of the current across the shunt resistor (13) with a setpoint voltage (Vset) and obtain a combined voltage (Vfb) supplying a feedback input (15) of the DC / DC converter (12).

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