Closed diving apparatus with emergency breathing gas supply function and method of supply

Abstract

This invention relates to a closed-circuit diving respirator and resupply method with emergency breathing gas replenishment function: An oxygen cylinder, oxygen pressure reducing valve, solenoid valve, and inhalation bag constitute an automatic oxygen supply pipeline; a dilution gas cylinder, dilution gas pressure reducing valve, automatic replenishment valve, and inhalation bag constitute an automatic replenishment pipeline; and an emergency breathing gas replenishment device is added, consisting of two manual switching valves, an oxygen supply nozzle, and a dilution gas nozzle. The dilution gas pressure reducing valve is a constant ratio type, and the oxygen supply nozzle is a constant mass flow nozzle. The input end of manual switching valve 1 is connected to the oxygen pressure reducing valve pipeline, output switching end 1 is connected to the solenoid valve pipeline, and output switching end 2 is connected to the oxygen supply nozzle pipeline. The input end of manual switching valve 2 is connected to the constant ratio pressure reducing valve pipeline, output switching end 1 is connected to the automatic replenishment valve pipeline, and output switching end 2 is connected to the dilution gas nozzle pipeline. When a fault occurs in the constant oxygen partial pressure control, an indicator is displayed and an alarm is issued. The diver manually switches between the two manual switching valves to achieve the emergency breathing gas replenishment function.

Description

Technical Field

[0001] This invention relates to the field of closed breathing apparatus technology, and in particular to a constant oxygen partial pressure closed breathing apparatus with emergency breathing gas supply function. Background Technology

[0002] When using a constant oxygen partial pressure closed-circuit respirator for deep-sea diving, if oxygen partial pressure control fails, an emergency open-circuit respirator must be used. However, it's difficult to achieve a suitable oxygen concentration in an emergency open-circuit respirator. If 1.3 ata is used as the maximum oxygen partial pressure, the oxygen concentration in the emergency cylinder at a depth of 100m can only reach a maximum of 12% (US Navy Diving Manual MK16), otherwise it won't provide sufficient dilution. Using this oxygen concentration for emergency breathing will pose a risk of hypoxia when decompressing to depths greater than 5m.

[0003] No suitable solution has been proposed abroad for this situation. For example, the US M16 constant oxygen partial pressure closed breathing apparatus, which can be used at a maximum depth of 90m, does not carry an emergency gas cylinder. When the breathing apparatus malfunctions, the surface signalman needs to lower the emergency breathing apparatus to the first stop, and the diver quickly ascends to the first stop to breathe using the emergency breathing apparatus. Since the deepest first stop at 300fsw (91.4m) on the MK16 decompression gauge is 180fsw (54.9m), filling the emergency breathing apparatus with gas at a 21% oxygen concentration can ensure safety throughout the decompression. However, during the period from the 300fsw malfunction to the first stop, the diver is actually using a malfunctioning breathing apparatus, which is extremely unsafe. Summary of the Invention

[0004] This invention addresses the problems and shortcomings of existing technologies by providing a constant oxygen partial pressure closed respirator with emergency breathing gas replenishment function.

[0005] The present invention solves the above-mentioned technical problems through the following technical solution:

[0006] This invention provides a closed-circuit diving respirator with emergency breathing gas replenishment function, comprising an automatic oxygen supply pipeline consisting of an oxygen cylinder, an oxygen pressure reducing valve, a solenoid valve, and an inhalation bag, and an automatic air replenishment pipeline consisting of a dilution gas cylinder, a dilution gas pressure reducing valve, an automatic air replenishment valve, and an inhalation bag. The invention is characterized by further comprising an emergency breathing gas replenishment device consisting of a manual switching valve 1, an oxygen supply nozzle, a manual switching valve 2, and a dilution gas nozzle. The dilution gas pressure reducing valve is a ratio pressure reducing valve, and the oxygen supply nozzle is a constant mass flow nozzle.

[0007] The input end of the manual switching valve 1 is connected to the oxygen pressure reducing valve pipeline, the output switching end 1 is connected to the solenoid valve pipeline, and the output switching end 2 is connected to the oxygen supply nozzle pipeline. The output switching end 1 of the manual switching valve 1 and the solenoid valve are in a normally open state. The input end of the manual switching valve 2 is connected to the proportional pressure reducing valve pipeline, the output switching end 1 is connected to the automatic gas replenishment valve pipeline, and the output switching end 2 is connected to the dilution gas nozzle pipeline. The output switching end 1 of the manual switching valve 2 and the automatic gas replenishment valve are in a normally open state.

[0008] The controller of the closed-circuit diving breathing apparatus is used to display and issue an emergency warning when the constant oxygen partial pressure control fails. Under the warning, the diver manually switches and adjusts the manual switching valve 1 and manual switching valve 2 to open the emergency oxygen supply pipeline consisting of the oxygen cylinder, oxygen pressure reducing valve, manual switching valve 1, oxygen supply nozzle and inhalation bag, and to open the emergency dilution gas supply pipeline consisting of the dilution gas cylinder, constant ratio pressure reducing valve, manual switching valve 2, dilution gas nozzle and inhalation bag.

[0009] This invention also provides an emergency breathing gas replenishment method for a closed-circuit diving respirator, which utilizes the aforementioned closed-circuit diving respirator and includes the following steps:

[0010] S1. Configure the constant ratio pressure reducing valve and the oxygen supply nozzle, wherein the oxygen supply nozzle is a constant mass flow nozzle;

[0011] S2. The controller of the closed-loop diving breathing apparatus displays and issues an emergency warning when the constant oxygen partial pressure control fails.

[0012] S3. Under warning, the diver manually switches and adjusts the manual switching valve 1 and manual switching valve 2 to connect the emergency oxygen supply pipeline consisting of the oxygen cylinder, oxygen pressure reducing valve, manual switching valve 1, oxygen supply nozzle and inhalation bag, and the emergency dilution gas supply pipeline consisting of the dilution gas cylinder, constant ratio pressure reducing valve, manual switching valve 2, dilution gas nozzle and inhalation bag.

[0013] The positive and progressive effects of this invention are as follows:

[0014] This invention designs a novel closed-circuit diving respirator, incorporating an emergency breathing gas replenishment device on a constant oxygen partial pressure respirator. This device is activated by two manually operated switching valves. When the oxygen partial pressure control of the closed-circuit diving respirator fails, the two manually operated switching valves disconnect the oxygen partial pressure control circuit and simultaneously activate the emergency breathing gas replenishment device. This device can replenish the breathing circuit with an appropriate ratio of oxygen and dilution gas carried by the constant oxygen partial pressure respirator according to changes in depth, maintaining the oxygen partial pressure within a safe range (0.2 ata-1.8 ata), eliminating the need to carry a separate emergency respirator. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of a closed-loop diving respirator with emergency breathing gas replenishment function, which is a preferred embodiment of the present invention.

[0016] Figure 2 The following is a coordinate system diagram of lines 11, 12, 21 and 22, which are preferred embodiments of the present invention.

[0017] Figure 3 The following is a coordinate system diagram of lines 1, 2, 3 and 4, which are preferred embodiments of the present invention. Detailed Implementation

[0018] like Figure 1 As shown, this embodiment of the invention provides a closed-circuit diving respirator with emergency breathing gas replenishment function. It includes an automatic oxygen supply pipeline consisting of an oxygen cylinder, an oxygen pressure reducing valve, a solenoid valve, and an inhalation bag; and an automatic air replenishment pipeline consisting of a dilution gas cylinder, a dilution gas pressure reducing valve, an automatic air replenishment valve, and an inhalation bag. An emergency breathing gas replenishment device consisting of a manual switching valve 1, an oxygen supply nozzle, a manual switching valve 2, and a dilution gas nozzle is also added. The dilution gas pressure reducing valve is a proportional pressure reducing valve; the oxygen supply nozzle is a constant mass flow nozzle, designed to be 1.2 L / min.

[0019] The input end of manual switching valve 1 is connected to the oxygen pressure reducing valve pipeline, the output switching end 1 is connected to the solenoid valve pipeline, and the output switching end 2 is connected to the oxygen supply nozzle pipeline. The output switching end 1 of manual switching valve 1 and the solenoid valve are in the normally open state, that is, manual switching valve 1 and the solenoid valve are connected. The input end of manual switching valve 2 is connected to the proportional pressure reducing valve pipeline, the output switching end 1 is connected to the automatic gas replenishment valve pipeline, and the output switching end 2 is connected to the dilution gas nozzle pipeline. The output switching end 1 of manual switching valve 2 and the automatic gas replenishment valve are in the normally open state, that is, manual switching valve 2 and the automatic gas replenishment valve are connected.

[0020] The controller of the closed-circuit diving breathing apparatus is used to display and issue an emergency warning when the constant oxygen partial pressure control fails. Under the warning, the diver manually switches and adjusts manual switching valve 1 and manual switching valve 2 to connect manual switching valve 1 and the oxygen supply nozzle, thereby connecting the emergency oxygen supply pipeline consisting of the oxygen cylinder, oxygen pressure reducing valve, manual switching valve 1, oxygen supply nozzle and breathing bag. It also connects manual switching valve 2 and dilution gas nozzle, thereby connecting the emergency dilution gas supply pipeline consisting of the dilution gas cylinder, constant ratio pressure reducing valve, manual switching valve 2, dilution gas nozzle and breathing bag.

[0021] In this embodiment, if a pure nitrogen or pure helium cylinder is used as the dilution gas, then pure nitrogen or pure helium can be used directly as the dilution gas. In the event of an oxygen circuit failure, as long as the oxygen cylinder and the dilution gas cylinder are normal, the breathing circuit can be safely supplied with gas through the emergency breathing gas supply device without the need for an additional emergency breathing apparatus.

[0022] When the constant oxygen partial pressure control malfunctions, the diver stops diving. At this point, the diver's oxygen consumption C is typically set as [minimum oxygen consumption, maximum oxygen consumption], specifically [0.5 L / min, 1 L / min]. To maintain a safe oxygen partial pressure in the breathing circuit, it is set as [minimum oxygen partial pressure, maximum oxygen partial pressure], specifically [0.2 ata, 1.8 ata]. The flow rate of the dilution gas at different depths is determined based on the oxygen consumption. The calculation formula is as follows:

[0023] It can be deduced that:

[0024]

[0025] P = Diving depth / 10 + 1

[0026] In the above formula, P represents the partial pressure of oxygen at a certain depth, and C represents the oxygen consumption of a diver, in L / min. The pure oxygen supply flow rate of the oxygen supply nozzle. The dilution gas flow rate for the dilution gas nozzle.

[0027] Based on the design depth of 100 meters for the respirator, the dilution gas flow rate at different depths was calculated using the formula under the conditions of minimum oxygen consumption (0.5 L / min) and minimum oxygen partial pressure (0.2 ata). And draw a straight line in the coordinate system as line 11 (see Figure 2 In the coordinate system, the horizontal axis represents depth (m), and the vertical axis represents flow rate (L / min).

[0028] The dilution gas flow rate at different depths was calculated using the formula under the conditions of minimum oxygen consumption (0.5 L / min) and maximum oxygen partial pressure (1.8 ata). And draw a straight line in the coordinate system as line 12 (see Figure 2 (The dilution gas flow rate corresponding to a depth of 100 meters). = (1.2 - 0.5) * (11 / 1.8 - 1) = 3.577.

[0029] The dilution gas flow rate at different depths was calculated using the formula under the conditions of maximum oxygen consumption (1 L / min) and minimum oxygen partial pressure (0.2 ata). And draw a straight line in the coordinate system as line 21 (see Figure 2 (The dilution gas flow rate corresponding to a depth of 100 meters). = (1.2 - 0.5) * (11 / 1.8 - 1) = 10.8.

[0030] The dilution gas flow rate at different depths was calculated using the formula under the conditions of maximum oxygen consumption (1 L / min) and maximum oxygen partial pressure (1.8 ata). And draw a straight line in the coordinate system as line 22 (see Figure 2 ).

[0031] In the coordinate system, the two lines corresponding to the overlapping range between lines 11 and 12 and between lines 21 and 22 are lines 12 and 21, respectively. The lower line (line 12) and the upper line (line 21) are respectively designated as line 1 (minimum oxygen consumption, maximum oxygen partial pressure) and line 2 (maximum oxygen consumption, minimum oxygen partial pressure) (see...). Figure 3 ).

[0032] Line 1 represents the minimum oxygen consumption and maximum oxygen partial pressure. Based on the coordinates at the design depth of line 1 (design depth 100), Draw a straight line as line 3 using the coordinates of 3.577 and the origin (0, 0). Figure 3 ).

[0033] Line 2 represents the maximum oxygen consumption and minimum oxygen partial pressure. Based on the coordinates at the design depth of line 2 (design depth 100), 10.8) and the origin coordinates (0, 0) to draw a straight line as line 4 (see Figure 3 ).

[0034] The proportional range of the proportional pressure reducing valve is determined to be [0.036, 0.108] based on the slopes K=0.036 and K=0.108 of line 3 and line 4, respectively.

[0035] This invention also provides an emergency breathing gas replenishment method for a closed-circuit diving respirator, which utilizes the aforementioned closed-circuit diving respirator and includes the following steps:

[0036] S1. Configure a constant ratio pressure reducing valve and an oxygen supply nozzle. The oxygen supply nozzle is a constant mass flow nozzle.

[0037] When the constant oxygen partial pressure control malfunctions, the diver stops diving. At this point, the diver's oxygen consumption C is typically set as [minimum oxygen consumption, maximum oxygen consumption], specifically [0.5 L / min, 1 L / min]. To maintain a safe oxygen partial pressure in the breathing circuit, it is set as [minimum oxygen partial pressure, maximum oxygen partial pressure], specifically [0.2 ata, 1.8 ata]. The flow rate of the dilution gas at different depths is determined based on the oxygen consumption. The calculation formula is as follows:

[0038] It can be deduced that:

[0039]

[0040] P = Diving depth / 10 + 1

[0041] In the above formula, P represents the partial pressure of oxygen at a certain depth, and C represents the oxygen consumption of a diver, in L / min. The pure oxygen supply flow rate of the oxygen supply nozzle. The dilution gas flow rate for the dilution gas nozzle.

[0042] Based on the design depth of 100 meters for the respirator, the dilution gas flow rate at different depths was calculated using the formula under the conditions of minimum oxygen consumption (0.5 L / min) and minimum oxygen partial pressure (0.2 ata). And draw a straight line in the coordinate system as line 11 (see Figure 2 ).

[0043] The dilution gas flow rate at different depths was calculated using the formula under the conditions of minimum oxygen consumption (0.5 L / min) and maximum oxygen partial pressure (1.8 ata). And draw a straight line in the coordinate system as line 12 (see Figure 2 (The dilution gas flow rate corresponding to a depth of 100 meters). = (1.2 - 0.5) * (11 / 1.8 - 1) = 3.577.

[0044] The dilution gas flow rate at different depths was calculated using the formula under the conditions of maximum oxygen consumption (1 L / min) and minimum oxygen partial pressure (0.2 ata). And draw a straight line in the coordinate system as line 21 (see Figure 2 (The dilution gas flow rate corresponding to a depth of 100 meters). = (1.2 - 0.5) * (11 / 1.8 - 1) = 10.8.

[0045] The dilution gas flow rate at different depths was calculated using the formula under the conditions of maximum oxygen consumption (1 L / min) and maximum oxygen partial pressure (1.8 ata). And draw a straight line in the coordinate system as line 22 (see Figure 2 ).

[0046] The two lines corresponding to the overlapping range between lines 11 and 12 and between lines 21 and 22 are designated as line 1 (minimum oxygen consumption, maximum oxygen partial pressure) and line 2 (maximum oxygen consumption, minimum oxygen partial pressure), respectively (see...). Figure 3 ).

[0047] Line 1 represents the minimum oxygen consumption and maximum oxygen partial pressure. Based on the coordinates at the design depth of line 1 (design depth 100), Draw a straight line as line 3 using the coordinates of 3.577 and the origin (0, 0). Figure 3 ).

[0048] Line 2 represents the maximum oxygen consumption and minimum oxygen partial pressure. Based on the coordinates at the design depth of line 2 (design depth 100), 10.8) and the origin coordinates (0, 0) to draw a straight line as line 4 (see Figure 3 ).

[0049] The proportional range of the proportional pressure reducing valve is determined to be [0.036, 0.108] based on the slopes of line 3 (0.036) and line 4 (0.108).

[0050] S2. The controller of the closed-loop diving breathing apparatus displays and issues an emergency warning when the constant oxygen partial pressure control malfunctions.

[0051] S3. Under warning, the diver manually switches and adjusts manual switching valve 1 and manual switching valve 2 to connect the emergency oxygen supply pipeline consisting of oxygen cylinder, oxygen pressure reducing valve, manual switching valve 1, oxygen supply nozzle and breathing bag, and the emergency dilution gas supply pipeline consisting of dilution gas cylinder, fixed ratio pressure reducing valve, manual switching valve 2, dilution gas nozzle and breathing bag.

[0052] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but all such changes and modifications fall within the scope of protection of the present invention.

Claims

1. A closed-circuit diving respirator with emergency breathing gas replenishment function, comprising an automatic oxygen supply pipeline consisting of an oxygen cylinder, an oxygen pressure reducing valve, a solenoid valve, and an inhalation bag, and an automatic air replenishment pipeline consisting of a dilution gas cylinder, a dilution gas pressure reducing valve, an automatic air replenishment valve, and an inhalation bag, characterized in that, It also includes an emergency breathing gas supply device consisting of a manual switching valve 1, an oxygen supply nozzle, a manual switching valve 2, and a dilution gas nozzle. The dilution gas pressure reducing valve is a ratio pressure reducing valve, and the oxygen supply nozzle is a constant mass flow nozzle. The input end of the manual switching valve 1 is connected to the oxygen pressure reducing valve pipeline, the output switching end 1 is connected to the solenoid valve pipeline, and the output switching end 2 is connected to the oxygen supply nozzle pipeline. The output switching end 1 of the manual switching valve 1 and the solenoid valve are in a normally open state. The input end of the manual switching valve 2 is connected to the proportional pressure reducing valve pipeline, the output switching end 1 is connected to the automatic gas replenishment valve pipeline, and the output switching end 2 is connected to the dilution gas nozzle pipeline. The output switching end 1 of the manual switching valve 2 and the automatic gas replenishment valve are in a normally open state. The controller of the closed-circuit diving breathing apparatus is used to display and issue an emergency warning when the constant oxygen partial pressure control fails. Under the warning, the diver manually switches and adjusts the manual switching valve 1 and manual switching valve 2 to open the emergency oxygen supply pipeline consisting of the oxygen cylinder, oxygen pressure reducing valve, manual switching valve 1, oxygen supply nozzle and inhalation bag, and to open the emergency dilution gas supply pipeline consisting of the dilution gas cylinder, constant ratio pressure reducing valve, manual switching valve 2, dilution gas nozzle and inhalation bag. When the constant oxygen partial pressure control fails, the diver stops diving operation, at this time, the oxygen consumption C of the diver is set as [minimum oxygen consumption, maximum oxygen consumption], and the safe oxygen partial pressure in the breathing circuit is set as [minimum oxygen partial pressure, maximum oxygen partial pressure], and the flow of the dilution gas at different depths is determined according to the oxygen consumption The calculation formula is: , it is calculated that: ， P = Diving depth / 10 + 1 In the above formula, P represents the partial pressure of oxygen at a certain depth, and C represents the oxygen consumption of a diver, in L / min. This refers to the pure oxygen supply flow rate of the oxygen supply nozzle. The dilution gas flow rate for the dilution gas nozzle; Based on the design depth of the respirator, the dilution gas flow rate at different depths under the conditions of minimum oxygen consumption and minimum oxygen partial pressure was calculated using a calculation formula. A straight line, designated as line 11, is plotted in the coordinate system. The dilution gas flow rate at different depths under the conditions of minimum oxygen consumption and maximum oxygen partial pressure is then calculated using the formula. A straight line, designated as line 12, is plotted on a coordinate system. The dilution gas flow rate at different depths under conditions of maximum oxygen consumption and minimum oxygen partial pressure is then calculated using the appropriate formula. A straight line, designated as line 21, is plotted in the coordinate system. The dilution gas flow rate at different depths under the conditions of maximum oxygen consumption and maximum oxygen partial pressure is then calculated using the formula. And draw a straight line as line 22 in the coordinate system; The two lines corresponding to the overlapping range between lines 11 and 12 and between lines 21 and 22 are designated as line 1 and line 2, respectively. A line is drawn based on the coordinates of the design depth of line 1 and the origin coordinates as line 3. A line is drawn based on the coordinates of the design depth of line 2 and the origin coordinates as line 4. The lower limit and upper limit of the constant ratio range of the constant ratio pressure reducing valve are determined based on the slopes of lines 3 and 4, respectively. The dilution gas cylinder is a pure nitrogen cylinder or a pure helium cylinder.

2. The closed circuit underwater breathing apparatus with emergency breathing gas supply function according to claim 1, wherein The minimum consumption - maximum consumption of the diver's oxygen consumption C is 0.5-1 L / min, the minimum oxygen partial pressure and the maximum oxygen partial pressure of the safety oxygen partial pressure are 0.2-1.8 ata, the pure oxygen supply flow of the oxygen supply nozzle is 1.2 L / min, and the design depth of the breathing apparatus is 100 meters; Line 1 is the minimum oxygen consumption, maximum oxygen partial pressure, according to the coordinates of the design depth (design depth 100, 3.577) and the origin coordinates (0, 0) of line 3 as a straight line; Line 2 is the maximum oxygen consumption, minimum oxygen partial pressure, according to the coordinates of the design depth (design depth 100, 10.8) and the origin coordinates (0, 0) to draw a line as line 4; The proportional range of the proportional pressure reducing valve is determined to be [0.036, 0.108] based on the slopes of line 3 (0.036) and line 4 (0.108).

3. An emergency breathing gas supply method for a closed circuit diving rebreather, characterized by, The method of achieving this using the closed-circuit diving respirator of claim 1 includes the following steps: S1. Configure the constant ratio pressure reducing valve and the oxygen supply nozzle, wherein the oxygen supply nozzle is a constant mass flow nozzle; S2. The controller of the closed-loop diving breathing apparatus displays and issues an emergency warning when the constant oxygen partial pressure control fails. S3. Under warning, the diver manually switches and adjusts the manual switching valve 1 and manual switching valve 2 to open the emergency oxygen supply pipeline consisting of the oxygen cylinder, oxygen pressure reducing valve, manual switching valve 1, oxygen supply nozzle and inhalation bag, and to open the emergency dilution gas supply pipeline consisting of the dilution gas cylinder, fixed ratio pressure reducing valve, manual switching valve 2, dilution gas nozzle and inhalation bag. In S1, when the constant oxygen partial pressure control fails, the diver stops diving operation, at this time, the oxygen consumption C of the diver is set as [minimum oxygen consumption, maximum oxygen consumption], and the safe oxygen partial pressure in the breathing circuit is set as [minimum oxygen partial pressure, maximum oxygen partial pressure], and the flow of the dilution gas at different depths is determined according to the oxygen consumption The calculation formula is: , it is calculated that: ， P = Diving depth / 10 + 1 In the above formula, P is the absolute pressure at a certain depth, unit: ata, C is the oxygen consumption of the diver, unit: L / min, is the pure oxygen supply flow of the oxygen supply nozzle, is the dilution gas flow of the dilution gas nozzle; Based on the design depth of the respirator, the dilution gas flow rate at different depths under the conditions of minimum oxygen consumption and minimum oxygen partial pressure was calculated using a calculation formula. A straight line, designated as line 11, is plotted in the coordinate system. The dilution gas flow rate at different depths under the conditions of minimum oxygen consumption and maximum oxygen partial pressure is then calculated using the formula. A straight line, designated as line 12, is plotted on a coordinate system. The dilution gas flow rate at different depths under conditions of maximum oxygen consumption and minimum oxygen partial pressure is then calculated using the appropriate formula. A straight line, designated as line 21, is plotted in the coordinate system. The dilution gas flow rate at different depths under the conditions of maximum oxygen consumption and maximum oxygen partial pressure is then calculated using the formula. And draw a straight line as line 22 in the coordinate system; The two lines corresponding to the overlapping range between lines 11 and 12 and between lines 21 and 22 are designated as line 1 and line 2, respectively. A line is drawn based on the coordinates of the design depth of line 1 and the origin coordinates as line 3. A line is drawn based on the coordinates of the design depth of line 2 and the origin coordinates as line 4. The lower limit and upper limit of the constant ratio range of the constant ratio pressure reducing valve are determined based on the slopes of lines 3 and 4, respectively. In S3, the dilution gas cylinder is a pure nitrogen cylinder or a pure helium cylinder.

4. The method for emergency breathing gas supply for a closed circuit diving rebreather according to claim 3, wherein The minimum consumption - maximum consumption of the diver's oxygen consumption C is 0.5-1 L / min, the minimum oxygen partial pressure and the maximum oxygen partial pressure of the safe oxygen partial pressure are 0.2-1.8 ata, the pure oxygen supply flow of the oxygen supply nozzle is 1.2 L / min, and the design depth of the breathing apparatus is 100 meters; Line 1 is the minimum oxygen consumption, maximum oxygen partial pressure, according to the coordinates of the design depth (design depth 100, 3.577) and the origin coordinates (0, 0) of line 3 as a straight line; Line 2 is the maximum oxygen consumption, minimum oxygen partial pressure, according to the coordinates of the design depth (design depth 100, 10.8) and the origin coordinates (0, 0) to draw a line as line 4; The proportional range of the proportional pressure reducing valve is determined to be [0.036, 0.108] based on the slopes of line 3 (0.036) and line 4 (0.108).

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