A two-stage spiral conveyor for exhausting harmful gases from muck and an earth pressure balance shield

Abstract

This application relates to a two-stage screw conveyor for exhausting harmful gases from muck and an earth pressure balance shield, belonging to the technical field of construction control of earth pressure balance shields in complex strata. It includes: a first-stage screw conveyor with a first feed inlet for muck entry at its front end and a first discharge outlet for muck discharge at its rear end; a second-stage screw conveyor with a second feed inlet communicating with the first discharge outlet at its front end and a second discharge outlet for muck discharge at its rear end; an air inlet for pumping compressed air is also provided at the front end of the second-stage screw conveyor, and an exhaust port for sucking harmful gases is also provided at the rear end. This application adopts the layout method of the two-stage screw conveyor with high and low levels, which can stir and release and timely exhaust the harmful gases in the muck, avoiding directly exhausting harmful gases in the first-stage screw conveyor, resulting in adverse working conditions such as violent fluctuations in the earth pressure in the soil bin and instability of the tunnel face, providing technical support for the safe and efficient tunneling of earth pressure balance shields in strata rich in harmful gases.

Description

Technical Field

[0001] This application relates to the technical field of earth pressure balance shield construction control in complex strata, and particularly relates to a two-stage screw conveyor for pumping out harmful gases from muck and an earth pressure balance shield. Background Art

[0002] Shield tunnel boring machines have been widely used in the tunneling construction process of tunnels and underground space engineering due to their many excellent performances such as "fast tunneling speed, high quality of the formed tunnel, small construction disturbance, high comprehensive economic and social benefits, and safe, civilized, environmental protection in construction".

[0003] With the popularization and application of earth pressure balance shields in tunnels and underground space engineering, the geological adaptability level of screw conveyors has been significantly improved. However, with the increasing demand for shield construction in strata rich in harmful gases, single-stage screw conveyors for transporting ordinary muck and the like are already difficult to meet the requirements for preventing and controlling harmful gases at the construction site.

[0004] During the tunneling process of earth pressure balance shields in strata rich in harmful gases, harmful gases released from the muck are extremely likely to accumulate in the screw conveyor and induce explosion accidents, which has become an important factor restricting the safe and efficient tunneling of shield tunnels in complex strata. In view of the deficiencies of the single-stage screw conveyor of the earth pressure balance shield, a two-stage screw conveyor that can be used to pump out harmful gases is proposed, which can reduce the risk of explosion accidents during tunnel construction and ensure the safe and efficient tunneling of the earth pressure balance shield. Summary of the Invention

[0005] The embodiments of this application provide a two-stage screw conveyor for pumping out harmful gases from muck and an earth pressure balance shield to solve the problem that harmful gases released from the muck accumulate in the screw conveyor and induce explosion accidents during the tunneling process of earth pressure balance shields in strata rich in harmful gases.

[0006] The first aspect of the embodiments of this application provides a two-stage screw conveyor for pumping out harmful gases from muck, including:

[0007] A first-stage screw conveyor, with a first feed inlet for muck entering at the front end and a first discharge outlet for discharging muck at the rear end;

[0008] A second-stage screw conveyor, with a second feed inlet communicating with the first discharge outlet at the front end and a second discharge outlet for discharging muck at the rear end;

[0009] An air inlet for pumping compressed air is provided at the front end of the second-stage screw conveyor, and an exhaust outlet for sucking harmful gases in the second-stage screw conveyor is provided at the rear end.

[0010] In some embodiments, an air inlet pipe connected to a compressed air pump is provided at the air inlet, and an exhaust pipe connected to a negative pressure vacuum device is provided at the exhaust port;

[0011] The air inlet pipe introduces compressed air into the secondary spiral conveyor to carry harmful gases released by the muck, and the harmful gases are sucked out through the exhaust pipe and the negative pressure vacuum device.

[0012] In some embodiments, a gas concentration sensor for monitoring the concentration of harmful gases in the secondary spiral conveyor is provided inside the secondary spiral conveyor or at the exhaust port;

[0013] A gas pressure sensor for monitoring the compressed air pressure in the secondary spiral conveyor is provided inside the secondary spiral conveyor or at the air inlet;

[0014] Both the gas concentration sensor and the gas pressure sensor are connected to a controller, and the controller adjusts the pressure of the compressed gas according to the magnitude of the harmful gas concentration.

[0015] In some embodiments, both the primary spiral conveyor and the secondary spiral conveyor are inclined upward from the front end to the rear end;

[0016] The inclination angle of the secondary spiral conveyor is smaller than that of the primary spiral conveyor, and the length of the secondary spiral conveyor is greater than that of the primary spiral conveyor.

[0017] In some embodiments, the outer diameter of the secondary spiral conveyor is larger than that of the primary spiral conveyor, and the operating speed of the secondary spiral conveyor is smaller than that of the primary spiral conveyor;

[0018] The rotation direction of the secondary spiral conveyor is opposite to that of the primary spiral conveyor.

[0019] In some embodiments, the primary spiral conveyor includes a first cylinder body and a first auger shaft rotatably connected inside the first cylinder body, and a first spiral blade is fixedly provided on the first auger shaft;

[0020] The secondary spiral conveyor includes a second cylinder body and a second auger shaft rotatably connected inside the second cylinder body, and a second spiral blade is fixedly provided on the second auger shaft;

[0021] The spiral directions of the first spiral blade and the second spiral blade are opposite, and the diameter of the first cylinder body is smaller than that of the second cylinder body.

[0022] In some embodiments, a drainage channel is provided on the outer wall of the primary spiral conveyor, and a muck water content detection sensor is provided inside the primary spiral conveyor or on the drainage channel.

[0023] In some embodiments, the first outlet and the second inlet are hermetically connected to each other through a discharge channel. The second outlet is connected to a muck discharge funnel, and the muck discharge funnel is provided with a valve for adjusting the slag discharge aperture.

[0024] In some embodiments, a plurality of air inlets are arranged at intervals along the length direction of the secondary screw conveyor.

[0025] In the second aspect of the embodiments of the present application, an earth pressure balance shield is provided. The earth pressure balance shield includes:

[0026] The two-stage screw conveyor for pumping and discharging harmful gases from muck as described in any of the above embodiments located inside the earth pressure balance shield;

[0027] The bottom of the shield soil bin of the earth pressure balance shield is communicated with and hermetically connected to the first feed inlet of the primary screw conveyor.

[0028] The beneficial effects brought by the technical solutions provided in the present application include:

[0029] The embodiments of the present application provide a two-stage screw conveyor for pumping and discharging harmful gases from muck and an earth pressure balance shield. Since the two-stage screw conveyor for pumping and discharging harmful gases from muck in the present application is provided with a primary screw conveyor, the front end of the primary screw conveyor is provided with a first feed inlet for muck to enter, and the rear end is provided with a first discharge outlet for discharging muck; a secondary screw conveyor, the front end of the secondary screw conveyor is provided with a second feed inlet communicated with the first discharge outlet, and the rear end is provided with a second discharge outlet for discharging muck; the front end of the secondary screw conveyor is further provided with an air inlet for pumping compressed air, and the rear end of the secondary screw conveyor is further provided with an exhaust port for sucking harmful gases.

[0030] Therefore, by adopting the layout method of the two-stage screw conveyor with high and low levels, the two-stage screw conveyor for pumping and discharging harmful gases from muck in the present application can stir and release and timely pump and discharge the harmful gases in the shield muck, avoiding directly pumping and discharging harmful gases in the primary screw conveyor, resulting in adverse working conditions such as violent fluctuations in the soil bin pressure and instability of the tunnel face, and providing technical support for the safe and efficient tunneling of the earth pressure balance shield in the formation rich in harmful gases.

[0031] In addition, the two-stage screw conveyor for pumping and discharging harmful gases from muck in the present application can pump compressed air into the secondary screw conveyor, carry the harmful gases released from the muck to the exhaust port, the exhaust port sucks and discharges the harmful gases in the secondary screw conveyor, and finally pumps and discharges them to the ground through the exhaust pipeline for purification treatment. The air inlet is located at the bottom of the secondary screw conveyor, and the exhaust port is located at the top of the secondary screw conveyor, which helps to thoroughly displace the residual harmful gases inside the cavity of the secondary screw conveyor and effectively relieve the risk of explosion accidents inside the shield and the tunnel. Description of the Drawings

[0032] To more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the accompanying drawings required for the description of the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0033] Figure 1 It is a schematic structural diagram of a two-stage spiral conveyor of an embodiment of the present application;

[0034] Figure 2 It is a schematic structural diagram of a first-stage spiral conveyor of an embodiment of the present application;

[0035] Figure 3 It is a schematic structural diagram of a second-stage spiral conveyor of an embodiment of the present application;

[0036] Figure 4 It is a schematic structural diagram of an earth pressure balance shield of an embodiment of the present application.

[0037] Reference signs:

[0038] 1. Earth pressure balance shield; 2. Shield soil bin; 3. Two-stage spiral conveyor; 4. First-stage spiral conveyor; 5. Second-stage spiral conveyor; 6. Negative pressure vacuum equipment; 7. Gas concentration sensor; 8. Muck discharge funnel; 9. Drainage channel; 10. Discharge channel; 11. First spiral blade; 12. First auger shaft; 13. Second spiral blade; 14. Second auger shaft; 15. Air inlet; 16. Air inlet pipe; 17. Exhaust port; 18. Exhaust pipe; 19. Gas pressure sensor; 20. Compressed air pump; 21. Muck water content detection sensor. Specific embodiments

[0039] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are some, but not all, of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts fall within the scope of protection of the present application.

[0040] The embodiments of the present application provide a two-stage spiral conveyor and an earth pressure balance shield for exhausting harmful gases from muck, which can solve the problem that harmful gases released from muck accumulate in the spiral conveyor during the tunneling of an earth pressure balance shield in a formation rich in harmful gases, inducing an explosion accident.

[0041] See Figures 1 to 3As shown in the figure, in the first aspect of the embodiments of the present application, a two-stage screw conveyor for pumping and discharging harmful gases from muck is provided. The two-stage screw conveyor 3 includes:

[0042] A first-stage screw conveyor 4, with a first feed port for muck entry at the front end of the first-stage screw conveyor 4, and a first discharge port for discharging muck at the rear end of the first-stage screw conveyor 4. The muck entering the first-stage screw conveyor 4 from the first feed port is transported to the first discharge port under the conveying action of the first auger shaft 12 and then discharged.

[0043] A second-stage screw conveyor 5, with a second feed port communicating with the first discharge port at the front end of the second-stage screw conveyor 5, and a second discharge port for discharging muck at the rear end of the second-stage screw conveyor 5. The muck entering the second-stage screw conveyor 5 from the second feed port is transported to the second discharge port under the conveying action of the second auger shaft 14 and then discharged. The muck carrying harmful gases is fully released in the second-stage screw conveyor 5, providing sufficient space and time for the full release of harmful gases in the muck.

[0044] At the front end of the second-stage screw conveyor 5, there is also an air inlet 15 for pumping compressed air, and at the rear end of the second-stage screw conveyor 5, there is also an exhaust port 17 for sucking harmful gases inside the second-stage screw conveyor 5. The second-stage screw conveyor 5 stirs the muck fed by the first-stage screw conveyor 4 to fully release the harmful gases contained in the muck, and carries the harmful gases to the exhaust port 17 by introducing air into the air inlet 15 and then discharges them to the ground for purification treatment, so as to alleviate the risk of explosion accidents during the tunneling process of shield tunnels.

[0045] The two-stage screw conveyor for pumping and discharging harmful gases from muck in the embodiments of the present application can stir and release and timely pump and discharge harmful gases in shield muck by adopting a layout method with the two-stage screw conveyors arranged at different levels, avoiding directly pumping and discharging harmful gases in the first-stage screw conveyor 4, which may cause adverse working conditions such as drastic fluctuations in the soil chamber pressure and instability of the tunnel face, and providing technical support for the safe and efficient tunneling of earth pressure balance shields in strata rich in harmful gases.

[0046] In addition, the two-stage screw conveyor 3 for pumping and discharging harmful gases from muck can pump compressed air into the second-stage screw conveyor 5, carry the harmful gases released from the muck to the exhaust port 17, the exhaust port 17 sucks and discharges the harmful gases inside the second-stage screw conveyor 5, and finally pumps and discharges them to the ground for purification treatment through the exhaust pipeline.

[0047] The air inlet 15 of the second-stage screw conveyor 5 is located at the bottom of the front end of the second-stage screw conveyor 5, and the exhaust port 17 is located at the top of the rear end of the second-stage screw conveyor 5, which helps to completely displace the residual harmful gases inside the cavity of the second-stage screw conveyor 5 and effectively alleviate the risk of explosion accidents inside the shield and tunnel.

[0048] In some alternative embodiments: Refer to Figures 1 to 3 As shown, an embodiment of the present application provides a two-stage screw conveyor for pumping and discharging harmful gases from muck. An air inlet pipe 16 connecting to a compressed air pump 20 is provided at an air inlet 15 of a secondary screw conveyor 5, and an exhaust pipe 18 connecting to a negative pressure vacuum device 6 is provided at an exhaust port 17. The air inlet pipe 16 introduces compressed air into the secondary screw conveyor 5 to carry the harmful gases released from the muck, and the harmful gases are sucked and discharged through the exhaust pipe 18 and the negative pressure vacuum device 6.

[0049] A gas concentration sensor 7 for monitoring the concentration of harmful gases in the secondary screw conveyor 5 is provided inside the secondary screw conveyor 5 or at the exhaust port 17. A gas pressure sensor 19 for monitoring the pressure of compressed air in the secondary screw conveyor 5 is provided inside the secondary screw conveyor 5 or at the air inlet 15; both the gas concentration sensor 7 and the gas pressure sensor 19 are connected to a controller (not shown in the figure), and the controller adjusts the pressure of the compressed gas according to the magnitude of the harmful gas concentration.

[0050] In the embodiment of the present application, the gas concentration sensor 7 and the gas pressure sensor 19 are arranged on the secondary screw conveyor 5, and the controller can dynamically adjust the air pressure pumped by the compressed air pump 20 according to the harmful gas concentration. When the concentration of harmful gases in the secondary screw conveyor 5 is too high, the pressure and flow rate of the air pumped by the compressed air pump 20 should be increased; when the concentration of harmful gases in the secondary screw conveyor 5 is lower than the defined threshold value, the pressure and flow rate of the air pumped into the compressed air pump 20 should be maintained or reduced to reduce the impact on the chamber pressure and the stability of the tunnel face.

[0051] In some alternative embodiments: Refer to Figures 1 to 3 As shown, an embodiment of the present application provides a two-stage screw conveyor for pumping and discharging harmful gases from muck. Both the primary screw conveyor 4 and the secondary screw conveyor 5 of the two-stage screw conveyor 3 are arranged to tilt upward from the front end to the rear end. Among them, the inclination angle of the secondary screw conveyor 5 is smaller than that of the primary screw conveyor 4, so that the length of the secondary screw conveyor 5 is greater than that of the primary screw conveyor 4, providing sufficient time for the release of harmful gases in the muck.

[0052] The cavity diameter of the secondary screw conveyor 5 is larger than that of the primary screw conveyor 4, and the operating speed of the secondary screw conveyor 5 is lower than that of the primary screw conveyor 4, which can provide sufficient space and time for the release of harmful gases in the shield muck and further release the harmful gases in the shield muck.

[0053] The rotation direction of the secondary screw conveyor 5 is opposite to that of the primary screw conveyor 4, which can relieve the adverse phenomenon that the same-direction stirring causes the pores on the muck surface to close and block the release channel of harmful gases, and further enables the harmful gases in the muck to be completely released.

[0054] In some alternative embodiments: Refer to Figures 1 to 3 As shown, the embodiment of the present application provides a two-stage screw conveyor for pumping and discharging harmful gases from muck. The first-stage screw conveyor 4 of the two-stage screw conveyor 3 includes a first cylinder and a first auger shaft 12 rotatably connected in the first cylinder. A first spiral blade 11 is fixedly provided on the first auger shaft 12.

[0055] The second-stage screw conveyor 5 includes a second cylinder and a second auger shaft 14 rotatably connected in the second cylinder. A second spiral blade 13 is fixedly provided on the second auger shaft 14. The spiral directions of the first spiral blade 11 and the second spiral blade 13 are opposite, and the diameter of the first cylinder is smaller than that of the second cylinder.

[0056] The second-stage screw conveyor 5 is provided with a plurality of air inlets 15 at intervals along the length direction, so that the compressed air entering the second-stage screw conveyor 5 is fully mixed with the muck, and the harmful gases released from the muck are carried out.

[0057] The first outlet of the first-stage screw conveyor 4 and the second inlet of the second-stage screw conveyor 5 are hermetically connected to each other through a discharge channel 10, so that the muck and harmful gases discharged from the first-stage screw conveyor 4 all enter the second-stage screw conveyor 5. A muck discharge funnel 8 is connected to the second outlet of the second-stage screw conveyor 5. The muck discharge funnel 8 is provided with a valve for adjusting the muck discharge aperture, which is used to control the flow rate of the muck discharged from the second-stage screw conveyor 5.

[0058] In some alternative embodiments: Refer to Figures 1 to 3 As shown, the embodiment of the present application provides a two-stage screw conveyor for pumping and discharging harmful gases from muck. A drainage channel 9 is provided on the outer wall of the first-stage screw conveyor 4 of the two-stage screw conveyor 3, and a muck water content detection sensor 21 is provided in the first-stage screw conveyor 4 or on the drainage channel 9. Excessive moisture can be discharged in time through the drainage channel 9 to prevent adverse phenomena such as gushing at the port part.

[0059] Specifically, a muck water content detection sensor 21 is arranged at the end of the drainage channel 9 to monitor the water content of the shield muck in real time. When the water content of the muck is greater than the gushing critical value, the drainage channel 9 should be opened to pump out the excessive moisture in the muck. When the water content of the muck is less than the gushing critical value, the drainage channel 9 can be closed to convey the muck to the first discharge port and then enter the second-stage screw conveyor 5.

[0060] Refer to Figure 4As shown in the figure, the second aspect of the embodiment of the present application provides an earth pressure balance shield, which includes: the two-stage spiral conveyor 3 for pumping and discharging harmful gases from muck in the earth pressure balance shield 1 as described in any of the above embodiments. The bottom of the shield muck bin 2 of the earth pressure balance shield 1 is in mutual communication and sealed connection with the first feed inlet of the first-stage spiral conveyor 4.

[0061] When the earth pressure balance shield 1 is tunneling in a stratum rich in harmful gases, the muck enters the interior of the shield muck bin 2 through the cutter head opening part, is conveyed to the discharge channel 10 by the first-stage spiral conveyor 4 and then enters the second-stage spiral conveyor 5, and the released harmful gases are carried from the bottom to the top by compressed air and discharged. When the content of harmful gases is lower than the critical threshold specified in the "Coal Mine Safety Regulations", it will enter the belt conveyor through the muck discharge funnel 8 and be transported to the ground muck yard.

[0062] When the concentration of harmful gases in the second-stage spiral conveyor 5 is higher than the critical threshold specified in the "Coal Mine Safety Regulations", the pressure and flow rate of the pumped air should be increased; when the concentration of harmful gases in the second-stage spiral conveyor 5 is lower than the critical threshold specified in the "Coal Mine Safety Regulations", the pressure and flow rate of the pumped air should be maintained to reduce the impact on the muck bin pressure and the stability of the tunnel face.

[0063] Working principle

[0064] The embodiment of the present application provides a two-stage spiral conveyor for pumping and discharging harmful gases from muck and an earth pressure balance shield. Since the two-stage spiral conveyor for pumping and discharging harmful gases from muck in the present application is provided with a first-stage spiral conveyor 4, the front end of the first-stage spiral conveyor 4 is provided with a first feed inlet for muck to enter, and the rear end is provided with a first discharge outlet for discharging muck; a second-stage spiral conveyor 5, the front end of the second-stage spiral conveyor 5 is provided with a second feed inlet communicating with the first discharge outlet, and the rear end is provided with a second discharge outlet for discharging muck; the front end of the second-stage spiral conveyor 5 is also provided with an air inlet 15, and the rear end of the second-stage spiral conveyor 5 is also provided with an exhaust port 17 for sucking harmful gases in the second-stage spiral conveyor 5.

[0065] Therefore, the two-stage spiral conveyor for pumping and discharging harmful gases from muck in the present application can stir and release and timely pump and discharge harmful gases in the shield muck by adopting the arrangement method of the two-stage spiral conveyor with high and low levels, avoiding directly pumping and discharging harmful gases in the first-stage spiral conveyor 4, causing adverse working conditions such as sharp fluctuations in the muck bin pressure and instability of the tunnel face, and providing technical support for the safe and efficient tunneling of the earth pressure balance shield in the stratum rich in harmful gases.

[0066] In addition, the two-stage spiral conveyor for pumping and discharging harmful gases of the present application can pump compressed air into the interior of the secondary spiral conveyor 5, carry the harmful gases released from the muck to the exhaust port 17. The exhaust port 17 sucks and discharges the harmful gases in the secondary spiral conveyor 5, and finally discharges them to the ground through the exhaust pipeline for purification treatment. The air inlet 15 is located at the bottom of the secondary spiral conveyor 5, and the exhaust port 17 is located at the top of the secondary spiral conveyor 5, which helps to thoroughly displace the residual harmful gases inside the cavity of the secondary spiral conveyor 5 and effectively mitigate the risk of explosion accidents inside the shield and tunnel.

[0067] In the description of the present application, it should be noted that the orientation or positional relationship indicated by terms such as "upper" and "lower" is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of the present application. Unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0068] It should be noted that in the present application, relative terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "including a..." does not exclude the existence of additional identical elements in the process, method, article or device including the said element.

[0069] The above description is only the specific implementation manners of the present application, enabling those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A two-stage spiral conveyor for pumping and discharging harmful gases from muck of a shield machine, characterized in that, Comprising: A primary screw conveyor (4), the front end of the primary screw conveyor (4) is provided with a first feed inlet for entering muck, and the rear end is provided with a first discharge outlet for discharging muck; A secondary screw conveyor (5), the front end of the secondary screw conveyor (5) is provided with a second feed inlet communicating with the first discharge outlet, and the rear end is provided with a second discharge outlet for discharging muck; The front end of the secondary screw conveyor (5) is provided with an air inlet (15) for pumping compressed air, and the rear end of the secondary screw conveyor (5) is provided with an exhaust port (17) for sucking harmful gases in the secondary screw conveyor (5); The outer diameter of the secondary screw conveyor (5) is larger than that of the primary screw conveyor (4), and the operating speed of the secondary screw conveyor (5) is less than that of the primary screw conveyor (4); The rotation direction of the secondary screw conveyor (5) is opposite to that of the primary screw conveyor (4).

2. A two-stage screw conveyor for pumping and discharging harmful gases from muck of a shield machine according to claim 1, characterized in that: The air inlet (15) is provided with an air inlet pipe (16) connected to a compressed air pump (20), and the exhaust port (17) is provided with an exhaust pipe (18) connected to a negative pressure vacuum device (6); The air inlet pipe (16) passes compressed air into the secondary screw conveyor (5) to carry harmful gases released by the muck, and is sucked and discharged through the exhaust pipe (18) and the negative pressure vacuum device (6).

3. A two-stage screw conveyor for pumping and discharging harmful gases from muck of a shield machine according to claim 1 or 2, characterized in that: A gas concentration sensor (7) for monitoring the concentration of harmful gases in the secondary screw conveyor (5) is provided inside the secondary screw conveyor (5) or at the exhaust port (17); A gas pressure sensor (19) for monitoring the compressed air pressure in the secondary screw conveyor (5) is provided inside the secondary screw conveyor (5) or at the air inlet (15); Both the gas concentration sensor (7) and the gas pressure sensor (19) are connected to a controller, and the controller adjusts the pressure of the compressed gas according to the magnitude of the harmful gas concentration.

4. A two-stage screw conveyor for pumping and discharging harmful gases from muck of a shield machine according to claim 1, characterized in that: Both the primary screw conveyor (4) and the secondary screw conveyor (5) are arranged to be inclined upward from the front end to the rear end; The inclination angle of the secondary screw conveyor (5) is smaller than that of the primary screw conveyor (4), and the length of the secondary screw conveyor (5) is greater than that of the primary screw conveyor (4).

5. A two-stage screw conveyor for pumping and discharging harmful gases from muck of a shield machine according to claim 1, characterized in that: The primary screw conveyor (4) includes a first cylinder body and a first auger shaft (12) rotatably connected inside the first cylinder body, and a first spiral blade (11) is fixedly arranged on the first auger shaft (12); The secondary screw conveyor (5) includes a second cylinder body and a second auger shaft (14) rotatably connected inside the second cylinder body, and a second spiral blade (13) is fixedly arranged on the second auger shaft (14); The spiral directions of the first spiral blade (11) and the second spiral blade (13) are opposite, and the diameter of the first cylinder is smaller than that of the second cylinder.

6. A two-stage spiral conveyor for pumping and discharging harmful gases from muck of a shield machine according to claim 1, characterized in that: A drainage channel (9) is provided on the outer wall of the primary spiral conveyor (4), and a muck water content detection sensor (21) is provided inside the primary spiral conveyor (4) or on the drainage channel (9).

7. A two-stage spiral conveyor for pumping and discharging harmful gases from muck of a shield machine according to claim 1, characterized in that: The first discharge port and the second feed port are hermetically connected to each other through a discharge channel (10), the second discharge port is connected to a muck discharge funnel (8), and the muck discharge funnel (8) is provided with a valve for adjusting the slag discharge aperture of the muck discharge funnel (8).

8. A two-stage spiral conveyor for pumping and discharging harmful gases from muck of a shield machine according to claim 1, characterized in that: A plurality of air inlets (15) are arranged at intervals along the length direction of the secondary spiral conveyor (5).

9. An earth pressure balance shield, characterized in that, The earth pressure balance shield (1) includes: A two-stage spiral conveyor (3) for pumping and discharging harmful gases from muck of a shield machine according to any one of claims 1 to 8 located inside the earth pressure balance shield (1); The bottom of the shield soil bin (2) of the earth pressure balance shield (1) is in communication and hermetically connected with the first feed port of the primary spiral conveyor (4).

Images