1- Technical Field

The medical & health care sector.

2- Background art:

The High-Flow Nasal Cannula (HFNC) is a medical device that has an effective role in providing an appropriate environment for respiratory system, as it provides inhalation and exhalation artificially, allowing the doctor to control both the medical air pressure, the intensity of its flow, its propelled volume to the lung and the concentration of oxygen in it.

Problems with the previous art:

The HFNC vary greatly according to their purpose and required performance. This also affects the complexity of their designs and later maintenance due to the complexity of spare parts and the difficulty of finding them.

The design problem lies in the complex techniques that lead to:

1- The scarcity of the device and its lack of abundance.

2- Its high cost.

3- Difficulty in maintaining it.

4- Scarcity of spare parts needed for its maintenance.

Especially in the conditions that the world is going through from a fast- spreading violent epidemic.

3- Disclosure of Invention

The goal that we all seek in the humanitarian crisis that the world is witnessing now is to find an HFNC system:

1- performs the functions of an advanced device.

2- is easy to assemble and maintain locally.

3- Its spare parts are always available in the local markets. To achieve these goals, two important parts were invented in this device, as expensive components were dispensed with, as follows:

• Delta Pressure Flow Tender Valve (DPFTV).

• Delta Pressure Nonlinear Interpolated Flowmeter (DPNIF).

Please see Fig. 8 and Fig. 9

Detailed Description:

The device consists of two main parts

1- Electric.

2- Pneumatic mechanical.

Electrical supply (power source):

Please see Figure 1

• It is the source of power for all electrical parts of the device.

• 12vdc battery

• A circuit to regulate the operation between the electronic circuit, the power source and the battery.

• (Fig. 8)

Mathematical and Logical Analysis:

It is the part responsible for analyzing all the information, whether from the sensors or from the user’s control, then deducing results and decisions on the basis of which it controls the system as a whole, which is called the processor and its peripherals. (Fig. 8)

Sensors and Monitoring:

It is the group of sensors that transmit all the physical values that the Processor is concerned with to conduct his analyzes and make his decisions.

Which are:

• Inhalation flow rate measure (Fig. 10)

• A measure of the oxygen concentration (Fig. 8) Operations and making decisions:

It contains the interface to implement CPU decisions which are as follows:

• The interface circuit unit to control the valve is proportional to the intensity of the oxygen flow. (Fig. 8 & 11)

Detailed description of the mechanical part

Air and oxygen supply

This unit contains:

• Air and oxygen supply channels.

• High pressure air inlet valve.

• High pressure oxygen inlet valve.

Regulation and reducing Pressure

This unit contains:

• Regulating and reducing oxygen pressure.

• Medical air pressure regulator and depressor.

Control of the intensity of the flow of air and oxygen:

This unit contains:

• Proportional valve to control the intensity of the oxygen flow (it receives the control signal from the electronic part).

Sensors and monitoring systems:

It is one of the common units between the electronic and mechanical parts.

What was invented in detail?

Please see Fig.10 and Fig.l 1

• Delta Pressure Flow Tender Valve (DPFTV).

• Delta Pressure Nonlinear Interpolated Flowmeter (DPNIF). First: Delta Pressure Flow Tender Valve

According to Fig. 11

The function of this system is to precisely control the intensity of the air flow by creating a pressure difference on channels of known specification and adjusting this pressure with respect to the servo motor (see item 1 in the panel No. 9), whose rotor is fixed to the rotary manual control handle of a "non-electric" manual pressure regulator (see element 3 in Panel No. 9).

The manual pressure regulator was chosen because it is one of the most resolution, accurate and stable in its values, so it is easy to control it through a servo motor installed on the hand of the rotary manual control.

We encountered obstacles in implementing the idea:

- The relationship between rotor deflection and pressure did not make a linear curve. This obstacle was solved by using a table of convergence points and then doing an interpolation or projecting small linear curves between the converging points.

- A slight change in flow occurs when there is a change in the input pressure, and this problem was solved by placing a pressure regulator before it.

- Failure to reach the required flow value with high accuracy using the direct control method. Therefore, we have used flow metrics in the work of monitoring the flow and controlling the flow based on it with a very accurate judgment.

Second: Delta Pressure Nonlinear Interpolated Flowmeter

According to Fig. 11

We faced several obstacles in using flowmeters in the local or global market, including:

- The cost of accurate flowmeters.

- Cheap flowmeters, some that are inaccurate, and others that affect the same measured value, change them and are difficult to control.

It is a system for measuring the intensity of the flow of air or oxygen and it is based on measuring pressure difference between two points (see Element 1 in Fog. 11) on a well-defined channel, where the intensity of the flow is deduced depending on the pressure difference and the properties of the tube (see element 2 in Fig. 11). With the use of interpolation methods, performance control tables, calibration, and linearization to reach the exact physical value.

What distinguishes this device from others? - Its accuracy as the techniques used above were used to reduce the effect of non-linearity.

- Its cheapness, as it relied on the same existing tube and on existing pressure gauges to measure pressure.

- It does not affect the measured value as it depends on the natural properties of the tube without obstructing the forced air.

Important parts to achieve safety:

Changing channel rudder:

According to Fig. No. 12 and 14

Its function when the pressure of oxygen and air disappears, as it opens the safety channel to become a source of outside air when the prepared mixed air stops.

Relief Valve: according to plate No. 10

The safety channel opens when the pressure exceeds the permissible, and this valve is present in all pressure regulators in the mechanical circuit.

Exploitation method:

This device was invented to be placed in all places that provide medical services, such as hospitals, clinics, health units, and equipped ambulances, and the respiratory system service is aimed at those who need artificial respiration due to the presence of deficiencies, defects or disease in their respiratory system, and is used under the supervision of a specialist doctor or trained nurse by the doctor.

New items to be protected:

1- A device for carrying out the function of supplying oxygen to the high flow is a pneumatic mechanical circuit that is managed and controlled by an electronic circuit, the mechanical circuit consists of a voltage regulator/reducer for compressed oxygen, and it also consists of a new component (DPFTV) that works to regulate the mixing ratios of both medical air and oxygen. It consists of a new scale that was invented to measure air flow to the lung and it is called (DPNIF), then the measure of the percentage of oxygen in mixed air.

2- A device for carrying out the function of supplying oxygen with high flow, consisting of a unit of the new innovation (DPFTV) according to claim No. 1, and it controls the pressure according to the electronic signal and achieves through the resulting pressure difference the flow of air, its value is calculated accurately as in figure No. 11.

3- Device: (DPFTV) Delta Pressure Flow Tender Valve to control the flow of air according to claim No. 2, it is a servo motor installed on a pressure regulator and the device receives its electrical signal from the motherboard (PCB) as on figure No. 11.

4- A device to carry out the function of supplying oxygen to high flow consisting of two units of the new innovation Delta Pressure Nonlinear Interpolated Flowmeter (DPNIF), according to claim No. 1 and it measures the pressure difference between two points with two cross- sectional areas, which increases the resolution of the pressure difference and then becomes a clear measure of flow The air when the other variables are constant, as in figure No. 11, and a device (DPNIF) to control the flow of air when the other variables are constant according to claim No. 4. It is two electronic pressure gauges installed on a flexible tube of variable diameter and the device sends its electrical signal to the motherboard (PCB) as in figure No. 10.

4- Brief description of drawing figures:

Figure No. 1: The theoretical design of the microcontrollers part in the designs

Figure No. 2: The conceptual design of the voltage and current regulation part in the designs

Figure No. 3: The conceptual design of the part of fixing the limbs in electronic designs.

Figure No. 4: The conceptual design of the switch part in electronic designs.

Figure No. 5: The conceptual design of the data display part of electronic designs.

Figure No. 6: the final shape of the printed board.

Figure No. 7: The theoretical design of the mechanical circuit: it consists of a high-pressure oxygen inlet valve (element 1 of Figure No. 7), two units of a pressure reducer and a regulator for both air and oxygen (element 2 of Figure No. 7) and a pressure gauge unit (element 3 of Figure No. 7) They are the mechanical part of the DPNIF unit.

Figure No. 8: outline of the electronic circuit.

Figure No. 9: a general diagram of the mechanical circuit.

Figure No. 10: the final illustration of the innovative design of the Flow Meter (DPNIF) Figure No. 11: Final Design of the Innovative Proportional Valve (DPFTV)

Figure No. 12 models of the oxygen sensor.

Description of the drawing board for the pneumatic circuit (HFNC): Initially, oxygen enters from the oxygen source into the DPFTV unit, (delta pressure flow tender valve) where the required oxygen level is set Consequently, with the entry of oxygen, the air enters from another branch to pass along the same path for mixing air and oxygen and then passing this amount to a pressure measuring device where it is located by sending an electrical signal indicating the measured pressure value, then the mixture is expelled into a tube with a larger diameter, a pressure is measured again and another electrical signal is passed with the value of the pressure

Thus, the amount of flow of the mixture is calculated.

Then the percentage of oxygen in the mixture is measured by an oxygen sensor.