WO2021249099A1

WO2021249099A1 - Structure for maintaining insufflation pressure and flow

Info

Publication number: WO2021249099A1
Application number: PCT/CN2021/093462
Authority: WO
Inventors: 达文波特詹姆斯·门罗; 卡波维奇约翰·伦纳德; 黄延平; 南巴坎姆瓦苏戴夫
Original assignee: 维景医疗科技(浙江)有限公司
Priority date: 2020-06-12
Filing date: 2021-05-12
Publication date: 2021-12-16
Also published as: DE112021003231T5; CN111594753A

Abstract

A structure for maintaining insufflation pressure and flow, comprising an adjusting three-way valve (3), a constant volume container (34), an exhaust two-way valve (5), a first pressure sensor (9) and a second pressure sensor; by means of connecting three interfaces of the adjusting three-way valve (3) to an air source (1), the constant volume container (34) and a supply end (4), respectively, by means of the adjusting three-way valve (3) turning on a channel by which the air source (1) inflates the constant volume container (34) or switching to turning on a channel by which the constant volume container (34) supplies air to the supply end (4), and by means of controlling the duration for which the adjusting three-way valve (3) turns on the channel by which the constant volume container (34) supplies air to the supply end (4), pressure adjustment and flow creation are implemented such that the amount of air discharged into the supply end (4) is controlled by means of the duration and frequency of the channel turned on by the adjusting three-way valve (3).

Description

A structure to maintain blowing pressure and flow

Technical field

The present invention relates to the technical field of gas pressure and flow adjustment, in particular to a structure for maintaining blowing pressure and flow.

Background technique

With the development of technology, the demand for pressure regulation in some industries is getting higher and higher. As the core link, precise pressure regulation often plays a decisive role.

At present, the industries that use pressure regulation include the medical device industry, especially during endoscopic surgery, where the pressure and flow of the insufflation method need to be maintained. However, existing equipment or structures often use an analog pressure regulator based on orifices and a large number of sensors to detect flow. For example, US Patent No. 4,207887 discloses a method that uses an analog pressure regulator to adjust the pressure and flow rate of the insufflation method. Structure, refer to Figure 1, Figure 1 is a structural diagram of the prior art using an analog pressure regulator to achieve pressure and flow adjustment in the insufflation method, including the analog pressure regulator 8 on the pipeline and the volume container row The volume container of the gas valve controls the pressure and detects the flow rate through the analog pressure regulator 8. At the same time, FIG. 2 is a structural diagram of an analog pressure regulator in the prior art, and discloses an existing analog pressure regulator 8, which is a two-stage pressure regulator, including a first-stage adjustment structure 81 and a second-stage adjustment Structure 82, and a communication port 83 is provided between the first-stage adjustment structure 81 and the second-stage adjustment structure 82. The first-stage adjustment structure 81 includes a first-stage valve body 811 and a first-stage adjustment screw 812. The second-stage adjustment The structure 82 includes a second-stage valve body 821 and a second-stage adjusting screw 822, and the first-stage valve body 811 and the second-stage valve body 821 are communicated through a communication port 83, and the first-stage valve body 811 is also provided with an inflow port 813. The second-stage valve body 821 is also provided with an outflow port 823. At the same time, a barrier with a first-stage orifice 814 is provided in the first-stage valve body 811 and located between the inflow port 813 and the communication port 83. A barrier with a second-stage orifice 824 is provided in the stage valve body 821 and between the communication port 83 and the outflow port 823. At the same time, one end of the first stage adjusting screw 812 extends into the first stage valve body 811 and is elastically connected There is a piston 84 matched with the first stage port 814. One end of the second stage adjusting screw 822 extends into the second stage valve body 821 and is connected with a piston 84 matched with the second stage port 824. By adjusting the first stage The adjustment screw 812 and the second-stage adjustment screw 822 realize the adjustment of the size of the first-stage orifice 814 and the second-stage orifice 824, thereby realizing the control of pressure and flow. Therefore, the above-mentioned structure for controlling pressure and flow through the analog pressure regulator is not only cumbersome, but also makes the adjustment pressure limited by the size of the orifice, which causes the maximum output flow to be limited by the analog pressure regulator, which presents a more restrictive problem.

Summary of the invention

In view of the above-mentioned problems in the prior art, the present aim is to provide a structure that maintains the blowing pressure and flow rate to provide a regulating valve, so that when the regulating valve is closed, the air source and the fixed volume container are connected, and the regulating valve is opened. When the valve is used, connect the fixed volume container and the supply side, and gradually increase the pressure on the supply side by repeatedly switching the regulating valve to realize the adjustment of the pressure and the creation of the flow rate, and the amount of gas discharged into the supply side is also controlled by the opening duration of the regulating valve , And the duration is calculated based on the supply pressure and the maximum required flow rate of the equipment.

The specific technical solutions are as follows:

A structure that maintains the blowing pressure and flow rate. It has such characteristics, including:

A fixed volume container;

A regulating valve, the regulating valve is connected to the gas source, the fixed volume container, and an output end of the regulating valve is connected to the supply end, the regulating valve is used to fill the fixed volume container with gas, and/ Or used to output gas from the fixed volume container to the supply end;

An exhaust valve, preferably an exhaust two-way valve, the exhaust two-way valve is arranged between the output end and the atmosphere, and is used to reduce the pressure at the supply end; in another case, the exhaust The valve can also be a three-way valve with a blocked interface;

A first pressure sensor for measuring the instantaneous pressure of the fixed volume container; and

A second pressure sensor is used to measure the instantaneous pressure of the supply end.

The above-mentioned structure for maintaining blowing pressure and flow rate, wherein the regulating valve is a regulating three-way valve.

The above-mentioned structure for maintaining blowing pressure and flow, wherein the regulating valve includes: a first two-way valve and a second two-way valve arranged in parallel, wherein the gas source and the fixed volume container pass through the The first two-way valve is connected, and the fixed volume container and the supply end are connected through the second two-way valve.

The above-mentioned structure for maintaining the blowing pressure and flow rate further includes a pressure regulator which is arranged between the air source and the regulating valve.

The above-mentioned structure for maintaining the blowing pressure and flow rate further includes a pressure safety release valve which is arranged between the pressure regulator and the regulating valve.

The above-mentioned structure for maintaining blowing pressure and flow rate further includes a supply end pressure release valve, and the supply end pressure release valve is arranged between the output end and the supply end.

The above-mentioned structure for maintaining the blowing pressure and flow rate, wherein the regulating valve and the two-way exhaust valve are both solenoid valves.

The above-mentioned structure for maintaining blowing pressure and flow rate, wherein an orifice is formed between the regulating three-way valve and the supply end.

The above-mentioned structure for maintaining blowing pressure and flow rate, wherein an orifice is formed between the three-way regulating valve and the supply end, and the orifice is connected to the second pressure sensor before the second pressure sensor. The supply ends are connected.

The above-mentioned structure for maintaining blowing pressure and flow rate, wherein there are a plurality of said regulating valves, and a plurality of said regulating valves are connected in series, and each of said regulating valves is connected with a said fixed volume container, That is, there are a plurality of the regulating valves and a corresponding plurality of the fixed volume containers.

The above-mentioned structure for maintaining blowing pressure and flow rate, wherein there are a plurality of said regulating valves, and a plurality of said regulating valves are connected in series, and each of said regulating valves is connected to the same fixed volume container , That is, there are a plurality of said regulating valves and one said fixed volume container.

The above-mentioned structure for maintaining the blowing pressure and flow rate, wherein the exhaust two-way valve is a normally closed valve.

The above-mentioned structure for maintaining blowing pressure and flow rate further includes a controller which is signally connected to the regulating valve and the two-way exhaust valve.

The above-mentioned structure for maintaining the blowing pressure and flow rate, wherein the volume and flow rate of the gas to be delivered are calculated by the change of the pressure measured by the second pressure sensor with the passage of time.

The above-mentioned structure for maintaining the blowing pressure and flow rate, wherein the total volume of the delivered gas is estimated by integrating the incremental volume calculated from the pressure change measured by the second pressure sensor.

The positive effects of the above technical solutions are:

The above-mentioned structure for maintaining the blowing pressure and flow rate is achieved by setting a regulating valve between the gas source and the fixed volume container, so that the passage of the gas source to inflate the fixed volume container can be opened by opening the regulating valve or switching to the opening by opening the regulating valve. The fixed-volume container is the gas supply channel on the supply side. The pressure and flow rate of the supply side are controlled by controlling the regulating valve to open the duration and frequency of the gas supply channel for the fixed-volume container, and the amount of gas discharged into the supply side is controlled by the regulating valve. Turn on the duration and frequency control of the channel.

Description of the drawings

Figure 1 is a schematic diagram of the use of an analog pressure regulator in the prior art to achieve blow-in pressure and flow adjustment;

Figure 2 is a structural diagram of an analog pressure regulator in the prior art;

Figure 3 is a schematic diagram of a structure for maintaining blowing pressure and flow rate of the present invention;

Figure 4 illustrates the use of two two-way valves configured to adjust the three-way valve;

Figure 5 illustrates the volume calculation.

In the drawings: 1. Air source; 2. Pressure regulator; 3. Adjusting three-way valve; 31. First interface; 32. Second interface; 33. Third interface; 34. Fixed volume container; 4. Supply end 5. Exhaust two-way valve; 6. Pressure safety release valve; 7. Supply-side pressure release valve; 8. Analog pressure regulator; 81. First-stage adjustment structure; 82. Second-stage adjustment structure; 83. Connectivity Port; 84, piston; 811, first stage valve body; 812, first stage adjusting screw; 813, inflow port; 814, first stage orifice; 821, second stage valve body; 822, second stage adjusting screw 823, outflow port; 824, second stage orifice; 9, first pressure sensor.

detailed description

In order to make the technical means, creative features, objectives and effects of the present invention easy to understand, the following embodiments will specifically illustrate the technical solutions provided by the present invention in conjunction with accompanying drawings 3 to 5, but the following content is not intended to limit the present invention. .

Fig. 3 is a structural diagram of an embodiment of a structure for maintaining blowing pressure and flow rate according to the present invention. As shown in Figure 3, the structure for maintaining blowing pressure and flow provided by this embodiment includes: a fixed volume container 34, a pressure regulator 2, a three-way regulating valve 3, a two-way exhaust valve 5, a pressure safety release valve 6 and Supply side pressure relief valve 7.

Specifically, the pressure regulator 2 is connected to and communicated with the gas source 1, and the inlet pressure of the gas source 1 is adjusted to a safe use range through the pressure regulator 2, to achieve preliminary pressure regulation and improve the protection performance.

Specifically, the regulating three-way valve 3 is connected to the gas source 1 and the fixed volume container 34, and an output end (for example, the third interface 33) of the regulating three-way valve 3 is connected to the supply end 4, and the regulating three-way valve 3 is used for the gas The source 1 fills the fixed-volume container 34 with gas, and/or is used to output gas from the fixed-volume container 34 to the supply end 4. At this time, the regulating three-way valve 3 includes three ports, the three ports are the first port 31, the second port 32, and the third port 33, and the third port 33 is a fixed volume container 34 connected to the supply end 4. At the same time, the first interface 31 selectively communicates with the second interface 32 or the third interface 33, so that when the first interface 31 and the second interface 32 are in communication, the first interface 31 and the third interface 33 are disconnected When the first interface 31 and the third interface 33 are connected, the first interface 31 and the second interface 32 are in a disconnected state. At the same time, the first port 31 is in communication with the fixed volume container 34, the second port 32 is in communication with the pressure regulator 2 connected to the gas source 1, and the third port 33 is an output port and communicates with the supply port 4. In fact, the first port 31 has input and output functions, and the second port 32 has input functions. The third interface 33 has an output function. Specifically, when gas enters the fixed-volume container 34 from the gas source 1, the first port 31 has an input function, and when the gas enters the supply end 4 from the fixed-volume container 34, the first port 31 has an output function.

The supply end here is the object that needs to be supplied with air, such as the patient cavity when the body cavity insufflation method is used during endoscopic surgery, that is, after the pressure regulator 2 is connected to the fixed volume container 34 by adjusting the three-way valve 3 , The fixed volume container 34 is in a disconnected state from the supply end 4. At this time, the gas from the gas source 1 is filled into the fixed volume container 34 by adjusting the three-way valve 3, and the fixed volume container 34 is connected to the fixed volume container 34 by adjusting the three-way valve 3. After the supply end 4 is connected, the fixed volume container 34 and the pressure regulator 2 are in a disconnected state, the gas in the fixed volume container 34 is output to the supply end 4 by adjusting the three-way valve 3, and the three-way valve 3 is controlled to open and fix The duration and frequency of the communication between the volume container 34 and the supply end 4 achieves the purpose of controlling the pressure and flow rate of the supply end 4, and realizes the adjustment of the pressure and flow rate, and adjusts the three-way valve 3 to open the fixed volume container 34 to communicate with the supply end 4. The duration of is calculated according to the demand pressure of the supply end 4 and the maximum allowable flow rate of the entire structure, which better meets the demand for precise pressure adjustment, avoids the problem that the adjustment pressure in the existing structure is limited by the size of the orifice, and improves the adaptability It converts the existing continuous pressure adjustment method into a discrete adjustment method formed by adjusting the repeated switching of the three-way valve 3. The pressure is maintained by the discharge volume of the discrete unit volume, and the discharge volume is calculated by the reduction of the fixed volume. , Thus no longer need to use other flow metering or measuring devices. In addition, the communication between the first interface 31 and the second interface 32 is a normally open path, and the communication between the first interface 31 and the third interface 33 is a normally closed path, ensuring safety.

Specifically, the exhaust two-way valve 5 is arranged between the third interface 33 of the regulating three-way valve 3 and the supply end 4, so that when the actual pressure of the supply end 4 increases to exceed the required pressure, the exhaust two-way valve 5 is activated , The gas at the supply end 4 is released into the atmosphere, so that the actual pressure of the supply end 4 is not higher than the required pressure, the structure design is more reasonable, and the safety is higher.

Specifically, a first pressure sensor 9 is also provided to measure the instantaneous pressure of the fixed-volume container 34, so as to measure the instantaneous pressure generated by the gas flowing through the fixed-volume container 34, provide data support, and calculate and deliver to the supply end. 4 of the flow. Preferably, the first pressure sensor 9 is arranged between the regulating three-way valve 3 and the fixed volume container 34.

Similarly, a second pressure sensor is also provided, and the second pressure sensor is provided between the regulating three-way valve 3 and the supply end 4. Therefore, the regulating three-way valve 3 and the exhaust two-way valve 5 can be automatically and accurately controlled, thereby achieving pressure and flow control.

In addition, a pressure safety release valve 6 is provided between the regulating three-way valve 3 and the pressure regulator 2.

The pressure threshold value is calculated according to the demand pressure of the supply end 4, so that when a pressure exceeding the threshold value is detected at the second interface 32 of the regulating three-way valve 3, the exhaust two-way valve 5 is opened to realize the pressure relief operation; Similarly, when a pressure exceeding the threshold value is detected between the first interface 31 of the regulating three-way valve 3 and the air source 1, the pressure safety release valve 6 is opened to realize the pressure relief operation, which further improves safety.

More specifically, the regulating three-way valve 3 and the exhaust two-way valve 5 are both solenoid valves, which can realize remote intelligent control, and realize the automatic adjustment of the opening and closing of the regulating three-way valve 3 and the exhaust two-way valve 5. The structure design is more Simple and safer.

More specifically, one or more throttling holes may also be provided between the third interface 33 of the three-way regulating valve 3 and the supply end 4, and the throttling holes are in communication with the supply end 4. Because the orifice is connected to the supply end 4, the pressure peak of the supply end 4 can be effectively reduced, and the protection is higher and the safety is better.

More specifically, in order to reduce the filling time for the fixed volume container 34, multiple regulating three-way valves 3 can be provided, and multiple regulating three-way valves 3 are connected in series, and each regulating three-way valve 3 is connected to a fixed volume container. 34. Make efficiency and response faster.

More specifically, another structure that replaces the conventional regulating three-way valve 3 is also provided. Figure 4 illustrates the use of two two-way valves configured to adjust the three-way valve. As shown in Figures 3 and 4, the two two-way valves are configured to be used as three-way valves. One port of each of the two two-way valves is connected to the fixed-volume container 34, and the remaining two ports of the two two-way valves are respectively connected to the supply end 4 and the pressure regulator 2 connected to the air source 1, to achieve conventional The function of the three-way valve makes the structure more flexible.

More specifically, the exhaust two-way valve 5 provided between the third interface 33 of the three-way regulating valve 3 and the supply end 4 is a normally closed valve, so that the actual pressure of the supply end 4 detected by the second pressure sensor is not greater than When the pressure is required, the exhaust two-way valve 5 is normally closed, and when the actual pressure of the supply end 4 detected by the second pressure sensor is greater than the required pressure, the exhaust three-way valve 5 is automatically switched to the open state to realize the pressure relief operation , The structure design is more reasonable and the safety is higher.

More specifically, a controller is also provided, and the controller signals are connected to the regulating three-way valve 3 and the exhaust two-way valve 5, and the actions of the regulating three-way valve 3 and the exhaust two-way valve 5 are controlled by the controller to achieve The intelligent adjustment and control of pressure and flow make the control more convenient and more accurate.

More specifically, the exhaust two-way valve 5 may be a three-way valve with a blocked interface, which improves the flexibility and adaptability of the equipment.

In addition, it also provides a way to calculate the flow rate of the gas flow through instantaneous pressure measurement. The input pressure of the pressure regulator 2 is defined as P _in , the instantaneous pressure of the fixed volume container 34 is P _c , and the instantaneous pressure of the supply end 4 is At the same time, P _pat _{also defines C cham} as the volume of the fixed-volume container 34. As shown in Fig. 3, Fig. 3 is a schematic diagram of a structure for maintaining blowing pressure and flow rate according to the present invention. The pressure regulator 2 has a certain input pressure P _in , the gas flow first enters the fixed volume container 34 through the regulating three-way valve 3, and generates an instantaneous pressure P _c in the fixed volume container 34, and then is fixed by the regulating three-way valve 3 The gas in the volume container 34 is released to the supply end 4, thereby increasing the pressure P _{pat at the} supply end 4. When the fixed volume container 34 _{is inflated within a fixed duration T c} , the duration of the gas transfer to the supply end 4 is T _p , at this time T _p + T _C is to adjust the three-way valve 3 to complete an inflation and exhaust cycle Duration. When P _{pat is} smaller than the regulating three-way valve, P _set is circulated in a relatively short period, so that P _{pat is} increased. The same is true when P _{pat is} greater than P _set and the two-way exhaust valve 5 is opened in a similar manner. When P _{pat is} greater than _{a certain amount of P set} (the amount exceeds a fixed or variable limit), the exhaust two-way valve 5 is opened until P _pat decreases to less than P _set . The limit may be a fixed amount, or may be an amount based on the value of _{P set.} Please refer to Appendix A for details.

The volume of gas delivered to the patient can be approximated by the integration of the delivery volume per cycle. The specific calculation theory is described in Appendix B.

The structure for maintaining the blowing pressure and flow rate provided by this embodiment includes an adjusting three-way valve 3, a fixed-volume container 34, an exhaust two-way valve 5, and a first pressure sensor 9 and a second pressure sensor; by adjusting the three-way valve The three ports of 3 are respectively connected to the gas source 1, the fixed volume container 34 and the supply end 4, and an exhaust two-way valve 5 is provided between the three-way valve 3 and the supply end 4. The three-way valve 3 is adjusted to provide a channel for the gas source 1 to inflate the fixed-volume container 34 or the three-way valve 3 is adjusted to a channel for the fixed-volume container 34 to supply air to the supply end 4. The pressure and flow rate of the supply end 4 are controlled by controlling the duration of the three-way valve 3 opening the fixed-volume container 34 for supplying air to the supply end 4, so as to realize the adjustment of the pressure and the flow rate.

The above are only preferred embodiments of the present invention, and do not therefore limit the implementation and protection scope of the present invention. For those skilled in the art, they should be aware of equivalent replacements and equivalents made by using the description and illustrations of the present invention. All solutions obtained by obvious changes should be included in the protection scope of the present invention.

Appendix A Control Plan

The user inputs the desired patient pressure (P _set ) in the graphical user interface (GUI).

_{The actual pressure (P pat} ) of the patient is sensed by the pressure sensor on the control board.

The control in the controller compares the actual patient pressure (P _pat ) with the patient pressure (P _set ) and calculates the error.

The control in the controller calculates the pulse width modulation output to the regulating three-way valve 3 or the exhaust two-way valve 5 according to the comparison value and the error sign.

In order to eliminate the fluctuation of the control when the error is close to zero, a dead zone can be merged.

Input the required patient flow rate (MAX) through the graphical user interface GUI.

When the required patient (MAX) flow rate meets the required flow rate, the patient pressure (P _set ) will be limited.

The graphical user interface GUI presents the actual patient pressure and patient flow as well as the required patient pressure and patient flow.

The incremental flow calculated by the control integration (see Appendix B) is also displayed in the GUI.

The alarm is activated when the patient is likely to be injured.

Respond to the alarm to alleviate the situation.

Appendix B Discussion of Volume Calculation

Assume that the gas quality is constant, and the increase in the gas volume causes the gas pressure to change. This approximates the volume of gas delivered and can be integrated over time to estimate the flow rate and volume delivered.

Therefore, the incremental flow rate can be approximated by volume due to changes in the chamber pressure for each valve cycle. At this time, the volume delivered to the patient can be estimated by integrating the volume delivered in each cycle.

According to the gas state equation PV=MRT,

At this time, P ₁ V ₁ ＝M ₁ RT ₁

And P ₂ V ₂ ＝M ₂ RT ₂

in,

P ₁ is the initial absolute pressure of the gas;

V ₁ is the initial volume of the gas;

M ₁ and M ₂ are equal and represent the gas quality;

P ₂ is the final absolute pressure of the gas;

V ₂ is the final volume of the gas;

R is a constant, an ideal gas constant;

Assuming that M1 and M2 are equal, and the condition is under isothermal conditions,

but,

If the quality and temperature are constant, then P ₁ V ₁ =P ₂ V ₂ ,

P ₁ V ₁ /P ₂ V ₂ =1,

or

V ₂ ＝P ₁ V ₁ /P ₂ ,

At the same time, ΔV=V ₁ -V ₂ , and represents the volume change

If V _{1 is} known, then:

For ΔP=P ₁ -P ₂ , ΔV=F×Q=(V ₁ -V ₂ ),

Among them, Q is the flow rate;

Then ΔV=(P ₁ V ₁ /P ₂ )-V ₁ ,

or

ΔV=V ₁ (P ₁ /P ₂ -1).

Claims

A structure for maintaining blowing pressure and flow, which is characterized in that it includes:

A fixed volume container;

A regulating valve, the regulating valve is connected to the gas source, the fixed volume container, and an output end of the regulating valve is connected to the supply end, the regulating valve is used to fill the fixed volume container with gas, and/ Or used to output gas from the fixed volume container to the supply end;

An exhaust valve, the exhaust valve is arranged between the output end and the atmosphere, and is used to reduce the pressure at the supply end;

A first pressure sensor for measuring the instantaneous pressure of the fixed volume container; and

A second pressure sensor is used to measure the instantaneous pressure of the supply end.
The structure for maintaining blowing pressure and flow according to claim 1, wherein the regulating valve is a regulating three-way valve.
The structure for maintaining blowing pressure and flow according to claim 1, wherein the regulating valve comprises: a first two-way valve and a second two-way valve arranged in parallel, wherein the air source and the The fixed volume container is connected through the first two-way valve, and the fixed volume container and the supply end are connected through the second two-way valve.
The structure for maintaining the blowing pressure and flow rate according to any one of claims 1 to 3, further comprising a pressure regulator arranged between the air source and the regulating valve .
The structure for maintaining blowing pressure and flow rate according to claim 4, further comprising a pressure safety release valve, the pressure safety release valve being arranged between the pressure regulator and the regulating valve.
The structure for maintaining blowing pressure and flow according to any one of claims 1 to 3, further comprising a supply end pressure relief valve, the supply end pressure relief valve being arranged at the output end and the Between the supply side.
The structure for maintaining the blowing pressure and flow rate according to any one of claims 1 to 3, wherein the regulating valve and the exhaust valve are both solenoid valves.
The structure for maintaining blowing pressure and flow rate according to claim 2, wherein one orifice is formed between the regulating three-way valve and the supply end.
The structure for maintaining blowing pressure and flow rate according to claim 2, wherein a throttle hole is formed between the three-way regulating valve and the supply end, and the throttle hole is formed on the first The two pressure sensors were previously communicated with the supply end.
The structure for maintaining blowing pressure and flow according to claim 1, characterized in that there are a plurality of said regulating valves, and a plurality of said regulating valves are connected in series, and each of said regulating valves is connected to one The fixed volume container.
The structure for maintaining blowing pressure and flow rate according to claim 1, wherein the exhaust valve is a normally closed valve.
The structure for maintaining blowing pressure and flow rate according to claim 5, further comprising a controller, and the controller is signally connected to the regulating valve and the exhaust valve.
The structure for maintaining the blowing pressure and flow rate according to claim 1, wherein the volume and flow rate of the gas to be delivered are calculated based on the change of the pressure measured by the second pressure sensor over time.
The structure for maintaining blowing pressure and flow according to claim 1, wherein the total volume of the gas delivered is integrated by the incremental volume calculated from the pressure change measured by the second pressure sensor To estimate.