An ultra-long piston duct ventilation system

Abstract

This invention relates to an ultra-long piston duct ventilation system. The intake chamber is divided into intake chamber one and intake chamber two, which are respectively connected to the left-line tunnel and the piston intake ventilation shaft via piston ducts. A low-pressure blower in intake chamber one is connected in series with the intake combination valve in intake chamber two. The exhaust chamber is divided into exhaust chamber one and exhaust chamber two, which are respectively connected to the right-line tunnel and the piston exhaust ventilation shaft via piston ducts. A low-pressure exhaust fan in exhaust chamber one is connected in series with the exhaust combination valve in exhaust chamber two. One-way airflow sensors are installed before and after the left-line combination valve on the first left-line piston duct and before and after the right-line combination valve on the first right-line piston duct. This invention provides supplementary power to the piston air in the ultra-long piston duct by adding a low-pressure blower, which works in conjunction with the piston air to achieve better tunnel ventilation, freeing the piston duct from length limitations and allowing the ground to provide ventilation shafts at appropriate locations.

Description

Technical Field

[0001] This invention relates to the field of tunnel ventilation technology, specifically to an ultra-long piston duct ventilation system. Background Technology

[0002] Underground station ventilation systems typically employ either a dual-piston or single-piston system. A dual-piston tunnel ventilation system uses two independent piston ventilation shafts, each corresponding to one train track. Each track has both tunnel ventilation and mechanical ventilation. The tunnel fan can mechanically supply air or exhaust smoke for its own track and can also supply air or exhaust smoke for the other track via a switching valve. A single-piston tunnel ventilation system has one piston ventilation shaft at ground level. One track has a piston ventilation duct, and both tracks have mechanical ventilation. The tunnel fan can mechanically supply air or exhaust smoke for its own track and can also supply air or exhaust smoke for the other track via a switching valve.

[0003] The tunnel ventilation system utilizes the piston effect, where the train's motion generates power to propel air through piston ducts and ventilation shafts into and out of the station and tunnel sections. However, this power is limited by the length of the piston duct and the number of bends, decreasing with increasing bends. Conventional station lengths are required to not exceed 50 meters, and the number of bends should not exceed four. If the piston duct is too long, the piston air expelled by the train entering the station will experience power loss due to air friction within the long passageway. After the train starts, it will pull any remaining polluted air back into the station and tunnel sections, creating piston air and reducing effective ventilation. Too many bends increase local resistance to the tunnel airflow, increasing the resistance to piston airflow and ultimately reducing tunnel ventilation efficiency. Furthermore, the length of the tunnel duct limits the layout of surface ventilation shafts; sometimes, reducing the length requires demolishing nearby buildings, resulting in fewer stations and increased costs. Summary of the Invention

[0004] The purpose of this invention is to provide an ultra-long piston duct ventilation system. By adding a small residual pressure fan, the piston air in the ultra-long piston duct is supplemented with power. The piston air works together with the piston air to achieve a better tunnel ventilation effect, so that the piston duct is no longer limited by length and the air outlet can be located at an appropriate position on the ground.

[0005] To achieve the above objectives, the technical solution of the present invention is an ultra-long piston air duct ventilation system, including a piston air inlet pavilion and a piston air outlet pavilion, further comprising an air inlet chamber and an air outlet chamber. The air inlet chamber is divided into an air inlet chamber one and an air inlet chamber two by a partition wall. The air inlet chamber one is connected to the left-line tunnel through a first left-line piston air duct, and the air inlet chamber two is connected to the piston air inlet pavilion through a second left-line piston air duct. A low residual pressure blower is installed in the air inlet chamber one, and an air inlet combined air valve is installed in the air inlet chamber two. The low residual pressure blower and the air inlet combined air valve are connected in series. The air outlet chamber is divided into an air outlet chamber one and an air outlet chamber two by a partition wall. The second ventilation chamber is connected to the right-line tunnel via the first right-line piston duct and to the piston exhaust ventilation pavilion via the second right-line piston duct. A small residual pressure exhaust fan is installed in the first ventilation chamber, and an exhaust combination valve is installed in the second ventilation chamber. The small residual pressure exhaust fan and the exhaust combination valve are connected in series. A left-line combination valve is installed on the first left-line piston duct, and a right-line combination valve is installed on the first right-line piston duct. One-way airflow sensors are installed before and after the left-line combination valve and before and after the right-line combination valve, respectively, with the airflow directions detected by the front and rear one-way airflow sensors being opposite.

[0006] Furthermore, an air supply tunnel fan is also installed inside the first air intake chamber, and the air supply tunnel fan is connected to the second air intake chamber.

[0007] Furthermore, an exhaust tunnel fan is also installed inside the first exhaust chamber, and the exhaust tunnel fan is connected to the second exhaust chamber.

[0008] Furthermore, the first left-line piston air duct is connected to the first right-line piston air duct through the first connecting ventilation duct. Check valves are provided on the first connecting ventilation duct near the first left-line piston air duct and on the first left-line piston air duct between the first connecting ventilation duct and the left-line combined air valve.

[0009] Furthermore, the first right-line piston air duct is connected to the first left-line piston air duct through the second ventilation duct. Check valves are installed on the second ventilation duct near the first right-line piston air duct and on the first right-line piston air duct between the second ventilation duct and the right-line combined air valve.

[0010] Furthermore, the node between the first connecting ventilation duct and the first right-line piston duct is located between the check valve and the right-line combined air valve on the first right-line piston duct, and the node between the second connecting ventilation duct and the first left-line piston duct is located between the check valve and the left-line combined air valve on the first left-line piston duct.

[0011] Furthermore, the first air inlet chamber is connected to the first air outlet chamber through a third ventilation duct, and a ventilation valve is provided on the third ventilation duct.

[0012] Furthermore, both the second left-line piston air duct and the second right-line piston air duct are equipped with silencers.

[0013] Furthermore, both the low residual pressure blower and the low residual pressure exhaust fan adopt an operation mode of power frequency operation and low frequency standby.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] (1) This invention provides supplementary power for the piston wind in the ultra-long piston duct by separately setting up a large-volume, low-pressure supply fan and a low-pressure exhaust fan; it uses a unidirectional airflow sensor set at the front end of the piston duct to detect the airflow and determine whether the piston duct is being ventilated or inlet, and adjusts the operating frequency of the low-pressure supply fan or the low-pressure exhaust fan according to the result. The tunnel ventilation effect is increased by the combined action of the low-pressure fan and the piston wind; when there is no piston wind in the tunnel, the low-pressure supply fan and the low-pressure exhaust fan are operated at low frequency to achieve energy saving.

[0016] (2) The piston air duct of the present invention is no longer limited by length, and the air outlet can be located on the ground at an appropriate position;

[0017] (3) Compared with the existing piston air system, the present invention optimizes the number of electric air valves in fire conditions, reduces the number of failure points, and increases safety;

[0018] (4) In order to extend the service life of the low residual pressure blower, the present invention does not adopt the on-off operation mode, but adopts the operation mode of power frequency operation and low frequency standby. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 A schematic diagram of an ultra-long piston air duct ventilation system provided in an embodiment of the present invention;

[0021] In the diagram: 1. Left-line combined air valve; 2. Check valve; 3. Low residual pressure supply fan; 4. Supply tunnel fan; 5. Inlet combined air valve; 6. Right-line combined air valve; 7. Low residual pressure exhaust fan; 8. Exhaust tunnel fan; 9. Exhaust combined air valve; 10. Connecting ventilation valve; 11. Silencer; 12. Exhaust chamber; 13. Inlet chamber; 14. Left-line tunnel; 15. Right-line tunnel; 16. First left-line piston air duct; 17. Second left-line piston air duct; 18. First right-line piston air duct; 19. Second right-line piston air duct; 20. First connecting ventilation duct; 21. Second connecting ventilation duct; 22. Third connecting ventilation duct. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] like Figure 1 As shown, this embodiment provides an ultra-long piston duct ventilation system, including a piston inlet ventilation shaft and a piston exhaust ventilation shaft, and further including an inlet chamber 13 and an exhaust chamber 12. The inlet chamber 13 is divided into an inlet chamber one and an inlet chamber two by a partition wall. The inlet chamber one is connected to the left-line tunnel 14 through a first left-line piston duct 16, and the inlet chamber two is connected to the piston inlet ventilation shaft through a second left-line piston duct 17. A low residual pressure blower 3 is installed in the inlet chamber one, and an inlet combined air valve 5 is installed in the inlet chamber two. The low residual pressure blower 3 and the inlet combined air valve 5 are connected in series. The exhaust chamber 12 is divided into an exhaust chamber one and an exhaust chamber two by a partition wall. The first exhaust chamber is connected to the right tunnel 15 via the first right piston duct 18, and the second exhaust chamber is connected to the piston exhaust pavilion via the second right piston duct 19. A small residual pressure exhaust fan 7 is installed in the first exhaust chamber, and an exhaust combination valve 9 is installed in the second exhaust chamber. The small residual pressure exhaust fan 7 and the exhaust combination valve 9 are connected in series. A left combination valve 1 is installed on the first left piston duct 16, and a right combination valve 6 is installed on the first right piston duct 18. One-way air flow sensors are installed before and after the left combination valve 1 and before and after the right combination valve 6, respectively, and the airflow directions detected by the front and rear one-way air flow sensors are opposite.

[0024] In this embodiment, a small residual pressure supply fan 3 and a small residual pressure exhaust fan 7 are separately set up to provide supplementary power for the piston air in the ultra-long piston air duct. The airflow direction and airflow rate are measured by unidirectional airflow sensors that are spaced apart at the front end of the first left-line piston air duct 16 and the first right-line piston air duct 18. Since the unidirectional airflow sensors, the small residual pressure supply fan 3 and the small residual pressure exhaust fan 7 are all electrically connected to the centralized controller, the centralized controller determines whether the piston air duct is being vented or vented based on the airflow rate values ​​of the unidirectional airflow sensors that are spaced apart. Based on the results, the operating frequency of the small residual pressure supply fan 3 or the small residual pressure exhaust fan 7 is adjusted. Under normal operating conditions, the small residual pressure fan and the piston air work together to increase the tunnel ventilation effect, so that the piston air duct is no longer limited by length, and the air outlet can be located at an appropriate position on the ground.

[0025] Furthermore, both the low residual pressure supply fan 3 and the low residual pressure exhaust fan 7 operate in a power frequency mode with low frequency standby. When there is piston wind in the tunnel, the low residual pressure supply fan 3 or the low residual pressure exhaust fan 7 is controlled by a centralized controller to operate at power frequency, increasing the tunnel's air intake or exhaust; when there is no piston wind in the tunnel, the low residual pressure supply fan 3 and the low residual pressure exhaust fan 7 are controlled by a centralized controller to operate at low frequency, achieving energy saving. Specifically, when the outward airflow in the piston duct is detected to be greater than or equal to 120m... 3 / h, which is the external exhaust ventilation, controls the small residual pressure exhaust fan 7 to operate at mains frequency, and the small residual pressure supply fan 3 to operate at low frequency; when the outward airflow in the piston duct is detected to be less than 120m... 3 / h means inward air intake, controlling the low residual pressure blower 3 to operate at industrial frequency and the low residual pressure exhaust blower 7 to operate at low frequency.

[0026] Furthermore, an air supply tunnel fan 4 is also installed in the first air intake chamber, which is connected to the second air intake chamber. An exhaust tunnel fan 8 is also installed in the first exhaust chamber, which is connected to the second exhaust chamber. When the left tunnel 14 or the right tunnel 15 is in a fire condition, the smoke in the left tunnel 14 or the right tunnel 15 enters the first exhaust chamber. Under the action of the exhaust tunnel fan 8, it is discharged through the second exhaust chamber via the piston exhaust fan tower. Simultaneously, the air supply tunnel fan 4 in the first air intake chamber reverses direction, and the smoke in the first exhaust chamber enters the first air intake chamber through the ventilation valve 10. It is then discharged through the second air intake chamber via the reverse direction of the air supply tunnel fan 4, thus improving smoke extraction efficiency.

[0027] Furthermore, the first left-line piston duct 16 is connected to the first right-line piston duct 18 via the first connecting ventilation duct 20. Check valves 2 are installed on the first connecting ventilation duct 20 near the first left-line piston duct 16 and on the first left-line piston duct 16 between the first connecting ventilation duct 20 and the left-line combined air valve 1. Furthermore, the first right-line piston duct 18 is connected to the first left-line piston duct 16 via the second connecting ventilation duct 21. Check valves 2 are installed on the second connecting ventilation duct 21 near the first right-line piston duct 18 and on the first right-line piston duct 18 between the second connecting ventilation duct 21 and the right-line combined air valve 6. Furthermore, the node between the first connecting ventilation duct 20 and the first right-line piston duct 18 is located between the check valve 2 on the first right-line piston duct 18 and the right-line combined air valve 6, and the node between the second connecting ventilation duct 21 and the first left-line piston duct 16 is located between the check valve 2 on the first left-line piston duct 16 and the left-line combined air valve 1. In this embodiment, the check valve 2 is used to control the unidirectional movement of airflow, so that the intake and exhaust airflows are unidirectional after the piston ducts are connected, avoiding the connection between the left and right line piston ducts; and under normal operating conditions, the second right-line piston duct 19 after the exhaust air chamber 12 and the second left-line piston duct 17 after the intake air chamber 13 are only unidirectional exhaust and unidirectional intake airflows, preventing wind-sensitive pollutants in the tunnel from being sucked into the station and the tunnel.

[0028] Furthermore, the first air intake chamber and the first exhaust chamber are connected through a third ventilation duct 22, and a ventilation valve 10 is provided on the third ventilation duct 22. When a fire occurs in the left or right tunnel 15, the ventilation valve 10 is opened to connect the air intake chamber 13 and the exhaust chamber 12, and the air supply tunnel fan 4 in the air intake chamber 13 is reversed. Together with the exhaust tunnel fan 8 in the exhaust chamber 12, the smoke is discharged through the piston air intake pavilion and the piston exhaust pavilion respectively, improving the smoke exhaust efficiency. At the same time, the combined air valve connected to the tunnel where no fire has occurred is closed to prevent smoke from escaping into the tunnel where no fire has occurred.

[0029] Furthermore, silencers 11 are provided on both the second left-line piston air duct 17 and the second right-line piston air duct 19 to reduce noise at the piston inlet and outlet air ducts and reduce pollution.

[0030] The operation modes of the ultra-long piston duct ventilation system in this embodiment include normal operating mode and fire operating mode. In normal operating mode, the ventilation valve 10 is normally closed, and the left-line combined air valve 1, the inlet combined air valve 5, the right-line combined air valve 6, and the exhaust combined air valve 9 are normally open. The one-way air flow sensor F1 is used to detect the airflow flow in the first right-line piston duct into the tunnel, the one-way air flow sensor F2 is used to detect the airflow flow in the first right-line piston duct out of the tunnel, the one-way air flow sensor F3 is used to detect the airflow flow in the first left-line piston duct into the tunnel, and the one-way air flow sensor F4 is used to detect the airflow flow in the first left-line piston duct out of the tunnel.

[0031] 1. Under normal operating conditions, the right-line piston ventilation system exits the station as follows: When the unidirectional airflow sensor F2 on the first right-line piston ventilation duct 18 detects an airflow rate greater than or equal to 120 m³ / s towards the outside of the tunnel, 3 / h, the centralized controller determines that the right tunnel 15 is ventilating, the low-pressure exhaust fan 7 is running at power frequency, the low-pressure supply fan 3 is running at low frequency, the piston air flows through the right line combined air valve 6 to the first exhaust air chamber, the low-pressure exhaust fan 7 provides additional power to the right line piston air, and the piston air in the first exhaust air chamber is discharged through the exhaust combined air valve 9 to the second exhaust air chamber and then discharged through the piston exhaust air pavilion.

[0032] 2. Under normal operating conditions, the left-line piston air exhaust process at the station is as follows: When the unidirectional airflow sensor F4 on the first left-line piston air duct 16 detects an airflow rate to the outside of the tunnel that is greater than or equal to 120 m³ / s... 3 / h, the centralized controller determines that the ventilation is from the left tunnel 14. The low-pressure exhaust fan 7 operates at the power frequency, and the low-pressure supply fan 3 operates at the low frequency. The piston air flows through the left combined air valve 1 and the second ventilation duct 21 to the first exhaust chamber. The low-pressure exhaust fan 7 provides additional power to the piston air in the left tunnel, and the piston air in the first exhaust chamber is discharged through the exhaust combined air valve 9 to the second exhaust chamber and then discharged through the piston exhaust ventilation pavilion.

[0033] 3. Under normal operating conditions, the right-line air intake mode procedure is as follows: When the one-way airflow sensor F1 on the first right-line piston duct 18 detects that the airflow rate into the tunnel is less than 120m³, 3 At / h, the centralized controller determines that the right-line tunnel 15 is receiving air. The low-pressure blower 3 operates at power frequency to supply air to the tunnel, while the low-frequency exhaust fan 7 operates at low pressure. Outdoor fresh air enters the second intake chamber from the piston intake pavilion. After being amplified by the low-pressure blower 3, it flows through the first intake chamber, the first left-line piston duct 16, and the first connecting ventilation duct 20 to the first right-line piston duct 18. After passing through the right-line combined air valve 6, it enters the right-line tunnel 15. The negative pressure in the tunnel created by the right-line train movement and the pressurized air intake from the low-pressure blower 3 form a series operation mode, with most of the fresh air being supplied to the right line and a small portion to the left line.

[0034] 4. Under normal operating conditions, the left-line air intake mode procedure is as follows: When the one-way airflow sensor F3 on the first left-line piston air duct 16 detects that the airflow rate flowing into the tunnel is less than 120m³, 3 At / h, the centralized controller determines that the left-line tunnel 14 is receiving air. The low-frequency operation of the low-pressure exhaust fan 3 supplies air to the section, while the low-frequency operation of the low-pressure exhaust fan 7 supplies air to the section. Outdoor fresh air enters the second intake chamber from the piston intake pavilion, and after being boosted by the low-pressure exhaust fan 3, it flows through the intake chamber to the first left-line piston duct 16. After passing through the left-line combined air valve 1, it enters the left-line tunnel 14. The negative pressure in the tunnel created by the movement of the left-line train and the pressurized air intake from the low-pressure exhaust fan 3 form a series operation mode, with most of the fresh air being supplied to the left line and a small portion entering the right line.

[0035] 5. The smoke exhaust process under the right-line fire condition is as follows: Close the left-line combined air valve 1, exhaust combined air valve 9, and intake combined air valve 5; open the connecting ventilation valve 10, the supply air tunnel fan 4 (reverse), and the exhaust air tunnel fan 8 to exhaust smoke from the right-line tunnel 15. The smoke in the right-line tunnel 15 enters the exhaust chamber 1 through the first right-line piston air duct 18. Part of the smoke is discharged into the exhaust chamber 2 through the exhaust air tunnel fan 8 and then discharged through the piston exhaust ventilation pavilion. The other part of the smoke enters the intake chamber 1 through the third connecting ventilation duct 22, is discharged into the intake chamber 2 through the reverse rotation of the supply air tunnel fan 4, and is then discharged through the piston intake ventilation pavilion.

[0036] 6. The smoke exhaust process under the fire condition mode of the left line is as follows: Close the right line combined air valve 6, exhaust combined air valve 9, and intake combined air valve 5; open the connecting ventilation valve 10, the supply air tunnel fan 4 (reverse), and the exhaust air tunnel fan 8 to exhaust smoke from the left line tunnel 14. The smoke in the left line tunnel 14 enters the intake air chamber 1 through the first left line piston air duct 16. Part of the smoke is discharged into the intake air chamber 2 through the reverse exhaust air tunnel fan 4 and then discharged through the piston intake air pavilion. The other part of the smoke enters the exhaust air chamber 1 through the third connecting ventilation duct 22, is discharged into the exhaust air chamber 2 through the exhaust air tunnel fan 8, and then discharged through the piston exhaust air pavilion.

[0037] 7. The process for the right-line fire air supply mode is as follows: Close the left-line combined air valve 1, exhaust combined air valve 9, and intake combined air valve 5; open the connecting ventilation valve 10, supply air tunnel fan 4, and exhaust air tunnel fan 8 (in reverse) to supply air to the right-line tunnel 15. The exhaust air tunnel fan 8 introduces fresh outdoor air into the intake air chamber 1 through the piston exhaust ventilation pavilion, and then enters the intake air chamber 1 through the third connecting ventilation duct 22. Together with the fresh outdoor air introduced by the supply air tunnel fan 4, it enters the right-line tunnel 15 through the first connecting ventilation duct 20 and the first right-line piston ventilation duct 18.

[0038] 8. The procedure for the left-line fire air supply mode is as follows: Close the right-line combined air valve 6, exhaust combined air valve 9, and intake combined air valve 5; open the connecting ventilation valve 10, supply air tunnel fan 4, and exhaust air tunnel fan 8 (in reverse) to supply air to the left-line tunnel 14. The exhaust air tunnel fan 8 introduces fresh outdoor air into the intake air chamber 1 through the piston exhaust ventilation pavilion, and then enters the intake air chamber 1 through the third connecting ventilation duct 22. Together with the fresh outdoor air introduced by the supply air tunnel fan 4, it enters the left-line tunnel 14 through the first left-line piston ventilation duct 16.

[0039] 9. For lines with a high number of train pairs, in order to avoid frequent switching between power frequency and low frequency by the small residual pressure blower 3 or the small residual pressure exhaust fan 7, the time interval between the switching frequency of the small residual pressure blower caused by the number of train pairs can be compared with the time interval required for the small residual pressure blower to switch its own frequency. The central controller can then determine the number of times the small residual pressure blower starts and stops per hour. When a certain number is reached, the small residual pressure blower enters the full-on mode.

[0040] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An ultra-long piston duct ventilation system, comprising a piston inlet ventilation shaft and a piston exhaust ventilation shaft, characterized in that: It also includes an air inlet chamber and an air outlet chamber. The air inlet chamber is divided into two chambers by a partition wall. Air inlet chamber one is connected to the left-line tunnel via a first left-line piston air duct, and air inlet chamber two is connected to the piston air inlet pavilion via a second left-line piston air duct. Air inlet chamber one is equipped with a low-pressure blower, and air inlet chamber two is equipped with an air inlet combination valve. The low-pressure blower and the air inlet combination valve are connected in series. The air outlet chamber is divided into two chambers by a partition wall. Air outlet chamber one is connected to the right-line tunnel via a first right-line piston air duct, and air outlet chamber two is connected to the piston exhaust pavilion via a second right-line piston air duct. Air outlet chamber one is equipped with a low-pressure exhaust fan, and air outlet chamber two is connected to the piston air outlet pavilion via a second right-line piston air duct. An exhaust combination valve is installed inside, and the low residual pressure exhaust fan is connected in series with the exhaust combination valve; a left-line combination valve is installed on the first left-line piston air duct, and a right-line combination valve is installed on the first right-line piston air duct. A one-way air flow sensor is installed before and after the left-line combination valve and before and after the right-line combination valve, respectively, and the airflow directions detected by the front and rear one-way air flow sensors are opposite; an air supply tunnel fan is also installed in the first air inlet chamber, and the air supply tunnel fan is connected to the second air inlet chamber; an exhaust tunnel fan is also installed in the first exhaust chamber, and the exhaust tunnel fan is connected to the second exhaust chamber; the first air inlet chamber and the first exhaust chamber are connected through a third ventilation duct, and a connecting ventilation valve is installed on the third ventilation duct.

2. The ultra-long piston duct ventilation system as described in claim 1, characterized in that: The first left-line piston air duct is connected to the first right-line piston air duct through the first connecting ventilation duct. Check valves are installed on the first connecting ventilation duct near the first left-line piston air duct and on the first left-line piston air duct between the first connecting ventilation duct and the left-line combined air valve.

3. The ultra-long piston duct ventilation system as described in claim 2, characterized in that: The first right-line piston air duct is connected to the first left-line piston air duct through the second ventilation duct. Check valves are installed on the second ventilation duct near the first right-line piston air duct and on the first right-line piston air duct between the second ventilation duct and the right-line combined air valve.

4. The ultra-long piston duct ventilation system as described in claim 3, characterized in that: The node between the first connecting ventilation duct and the first right-line piston duct is located between the check valve and the right-line combined air valve on the first right-line piston duct, and the node between the second connecting ventilation duct and the first left-line piston duct is located between the check valve and the left-line combined air valve on the first left-line piston duct.

5. The ultra-long piston duct ventilation system as described in claim 1, characterized in that: Both the second left-line piston air duct and the second right-line piston air duct are equipped with silencers.

6. The ultra-long piston duct ventilation system as described in claim 1, characterized in that: Both the low residual pressure blower and the low residual pressure exhaust fan adopt a power frequency operation mode with low frequency standby.

Images