Low-energy-consumption heading machine driver position compressed air type respiratory protection system and method

Abstract

The invention discloses a low-energy-consumption heading machine driver position compressed air type respiratory protection system and method. The system comprises a compressed air type respiratory protection part and a heading machine energy recovery part. The compressed air type breathing protection part comprises a compressed air type breathing mask and a compressed air filtering device; the heading machine energy recovery part comprises a piston mechanism, an air storage mechanism, an electric energy storage mechanism, a magnetic induction loop, a heat storage mechanism, a heat conduction switch and an electric control thermal phase change mechanism. By means of the compressed air type breathing protection part, purified air treated by the compressed air filtering device can be supplied to a driver of the heading machine through the compressed air type breathing mask, and the breathing safety of the driver of the heading machine in a complex environment is guaranteed; heat energy generated in the tunneling process of the tunneling machine can be recycled through the energy recycling part of the tunneling machine and converted into electric energy to supply power to the respiratory protection system, and the influence of dust in the working environment on a driver of the tunneling machine can be reduced to the maximum extent on the premise that low energy consumption is achieved.

Description

Technical Field

[0001] The invention relates to a breathing protection system and method for a driver of a tunnel boring machine, in particular to a compressed air breathing protection system and method for a driver of a tunnel boring machine with low energy consumption, belonging to the technical field of mine dust prevention and control. Background Art

[0002] Dust is an inevitable problem in the mining process. It is mainly generated by production activities such as blasting, mechanical chiseling, cutting, friction, and vibration. These dusts include fine particles such as rock dust and coal dust, collectively referred to as mine dust or mineral dust. The generation of mine dust is mainly concentrated in the process of drilling, excavation, crushing, screening, belt transmission, transportation, and reprinting. Mine dust removal technology usually has water spray dust removal, vacuum dust removal, filtration dust removal, high-voltage electrostatic dust removal and other solutions, but at present, a truly suitable dust removal technology has not been found for the harsh open working environment in China (such as mines, etc.), especially for the working face operation site of coal mining excavation and transportation equipment such as tunneling machines, underground mine loaders, and mine bucket loaders that require drivers to drive and operate. The working environment often faces multiple challenges such as dust, harmful gases, high temperature, and high humidity. These factors not only affect the driver's work efficiency, but also seriously threaten the driver's health and safety.

[0003] For the tunnel boring machine, during its operation, as the walking chassis drives the main body of the tunnel boring machine forward, the tunneling head at the front end of the tunneling working device rotates continuously to crush the rock, and the crushed rock is transported from the rear of the tunnel boring machine through the loading device and the transfer device. Before the tunnel is opened, the structure of the tunnel is like a blind hole structure with one end open and the other end closed, and the friction between the pick and the rock during the tunneling operation will generate a large amount of heat energy. Therefore, it is very difficult to ventilate the working environment during the tunnel boring machine. On the one hand, a large amount of heat energy is often accumulated, and it is difficult to use mine ventilation for heat dissipation. On the other hand, the dust generated by the crushed rock is easy to spread around the working environment of the tunnel boring machine and is difficult to be discharged by mine ventilation. Therefore, the labor intensity of the tunnel boring machine driver is high and he is prone to fatigue. At the same time, the tunnel boring machine is expensive, complex in structure, and has large energy consumption and loss. How to develop a low-energy respiratory protection system for the tunnel boring machine driver to reduce the impact of dust in the working environment on the tunnel boring machine driver and maximize the health and safety of the tunnel boring machine driver is a problem that needs to be solved in the industry. Summary of the invention

[0004] In view of the problems existing in the above-mentioned prior art, the present invention provides a low-energy consumption tunnel boring machine driver position compressed air type respiratory protection system and method, which can minimize the impact of dust in the working environment on the tunnel boring machine driver and ensure the health and safety of the tunnel boring machine driver under the premise of achieving low energy consumption.

[0005] To achieve the above purpose, the low-energy consumption roadheader driver's position compressed air breathing protection system includes a compressed air breathing protection part and a main control box;

[0006] The compressed air respiratory protection part includes a compressed air breathing mask, a compressed air filter device and a high-pressure air pipeline;

[0007] The compressed air breathing mask comprises a breathing mask body, an activated carbon composite high-efficiency filter membrane filtering mechanism, an adjustable mask strap, a breathing detection intelligent chip, an air volume control mechanism and a mask connecting pipe; the activated carbon composite high-efficiency filter membrane filtering mechanism and the adjustable mask strap are respectively installed on the breathing mask body; the breathing detection intelligent chip is arranged inside the breathing mask body; the air volume control mechanism including the electric control flow regulating valve is arranged inside the mask connecting pipe connected to the breathing mask body, and the mask connecting pipe is also provided with an air inlet switch;

[0008] The compressed air filtering device is fixedly installed on the tunnel wall of the tunnel, and the compressed air filtering device includes an oil-water separator, a high-efficiency filtering and purification chamber, a gas double purifier, a clean gas delivery pipeline, an electric control valve and a gas concentration detector; the input end of the oil-water separator is connected to the high-pressure gas pipeline, the high-pressure gas pipeline is connected to the compressed air delivery pipeline of the mine ventilation system, the output end of the oil-water separator is connected to the output end of the high-efficiency filtering and purification chamber, the output end of the high-efficiency filtering and purification chamber is connected to the input end of the electric control valve through the clean gas delivery pipeline, the input end of the gas double purifier is connected to the output end of the electric control valve, the output end of the gas double purifier is connected to the mask connecting pipe of the compressed air breathing mask through the air guide pipe, the gas concentration detector is arranged in the high-efficiency filtering and purification chamber, the high-efficiency filtering and purification chamber is provided with an activated carbon composite high-efficiency filter membrane, and the gas double purifier is provided with an ultraviolet disinfection mechanism and a sterilizing filter net;

[0009] The main control box includes a controller, which is electrically connected to a breathing detection intelligent chip, an electric flow regulating valve of an air volume control mechanism, an air inlet switch, an ultraviolet disinfection mechanism of a gas double purifier, an electric control valve and a gas concentration detector.

[0010] As a further improvement of the present invention, the tunnel boring machine comprises a tunnel boring machine body and a tunnel boring working device installed on the tunnel boring machine body, the tunnel boring working device as a whole is installed on the tunnel boring machine body through a supporting mechanism, the tunnel boring working device comprises a tunnel boring head, and the low-energy consumption tunnel boring machine driver position compressed air type breathing protection system further comprises a tunnel boring machine energy recovery part arranged on the tunnel boring working device; the main control box is arranged on the tunnel boring machine body;

[0011] The energy recovery part of the roadheader includes a piston mechanism, an air storage mechanism, an electric energy storage mechanism, a magnetic induction coil, a heat storage mechanism, a thermal conduction switch and an electrically controlled thermal phase change mechanism;

[0012] The rear end of the boring head with a hollow inner cavity structure is coaxially fixedly connected to the front end of the piston mechanism of the sleeve structure, and the rear end of the piston mechanism of the sleeve structure is coaxially fixedly connected to the barrel mouth of the air storage mechanism of the barrel structure. The inner cavity of the boring head, the inner cavity of the piston mechanism and the inner cavity of the air storage mechanism together form a closed vacuum space.

[0013] An elastic airbag I is arranged in the tunneling head, and the elastic airbag I is filled with a pressurized gas working medium. An elastic airbag II is arranged in the air storage mechanism, and the elastic airbag II is filled with a pressurized gas working medium. The air storage mechanism also includes an air pressure sensor arranged in the elastic airbag II. A piston cylinder I and a piston cylinder II are coaxially and symmetrically fixed in the piston mechanism, and the piston I in the piston cylinder I and the piston II in the piston cylinder II are coaxially and fixedly installed and connected through a piston connecting rod. The piston I of the piston cylinder I is transmission-connected to the elastic airbag I, and the piston II of the piston cylinder II is transmission-connected to the elastic airbag II.

[0014] The magnetic induction coil is coaxially fixedly arranged inside or outside the piston mechanism, and the magnetic induction coil is in a state of being sleeved on the outside of the piston connecting rod. The electric energy storage mechanism including the charging and discharging circuit and the rechargeable battery is installed on the main body of the tunnel boring machine, and the two ends of the piston connecting rod are electrically connected to the electric energy storage mechanism through wires respectively;

[0015] The heat storage mechanism includes a filling heat conductive coating and a heat insulating coating, wherein the filling heat conductive coating including a heat conductive material is arranged on the inner surface of the closed vacuum space, and the filling heat conductive coating on the inner surface of the boring head is connected with the filling heat conductive coating on the inner surface of the piston mechanism through a heat conductive switch, and the heat insulating coating including a heat insulating material is at least arranged on the outer surface of the piston mechanism;

[0016] The electrically controlled thermal phase change mechanism is arranged close to the elastic airbag I, or the electrically controlled thermal phase change mechanism is arranged inside the elastic airbag I, and a thermal phase change material is arranged inside the electrically controlled thermal phase change mechanism;

[0017] The electric energy storage mechanism, the air pressure sensor, the thermal conductivity switch and the electrically controlled thermal phase change mechanism are electrically connected to the controller of the main control box respectively.

[0018] As a further improvement of the present invention, the electrically controlled thermal phase change mechanism is provided in two groups, one group is provided against the elastic airbag I, or is provided in the elastic airbag I, and the other group is provided against the elastic airbag II, or is provided in the elastic airbag II.

[0019] As a further improvement of the present invention, the piston connecting rod is connected to the piston mechanism via a piston connecting rod guide structure fixedly arranged in the piston mechanism sleeve structure along the front-rear direction.

[0020] As a further improvement of the present invention, the front end of piston I of piston cylinder I is coaxially arranged with elastic airbag I, and the rear end of piston II of piston cylinder II is coaxially arranged with elastic airbag II.

[0021] As an embodiment of the present invention, the thermally conductive material filling the thermally conductive coating is asphalt-based carbon fiber, or graphene fiber, or graphene composite carbon fiber; the thermally insulating material of the thermally insulating coating is nanoporous aerogel, or glass wool, or rock wool; the thermal phase change material in the electrically controlled thermal phase change mechanism is a molten salt phase change material, or an organic phase change material, or an alloy phase change material.

[0022] As a preferred embodiment of the present invention, the pressurized gas working medium is hydrogen or helium.

[0023] A low-energy consumption tunnel boring machine driver position compressed air type breathing protection method, before the tunnel boring machine is started, ensure that the compressed air delivery pipeline of the mine ventilation system is connected with the high-pressure gas pipeline, the tunnel boring machine driver wears the breathing mask body and starts the main control box, and the controller controls the start of the electric control flow regulating valve of the air volume control mechanism, the air inlet switch, the ultraviolet disinfection mechanism of the gas double purifier, the electric control valve, the gas concentration detector and the air pressure sensor;

[0024] The pressurized air in the high-pressure gas pipeline is separated and purified by the oil-water separator and then enters the high-efficiency filtration purification chamber. The gas concentration detector feeds back the gas concentration data in the high-efficiency filtration purification chamber to the controller in real time. The activated carbon composite high-efficiency filter membrane in the high-efficiency filtration purification chamber finely filters and purifies the pressurized air and then enters the gas double purifier through the clean gas delivery pipeline and the electric control valve. The ultraviolet disinfection mechanism and the sterilization filter net in the gas double purifier sterilize and filter the pressurized air and then enter the breathing mask body after reducing the pressure through the air guide pipe, the air volume control mechanism, the mask connecting pipe and the air inlet switch. The breathing detection intelligent chip feeds back the inhalation volume data of the tunnel boring machine driver to the controller in real time; when the breathing detection intelligent chip feeds back that the inhalation volume of the tunnel boring machine driver exceeds the set range, the controller controls the electric control flow regulating valve of the air volume control device to adjust the flow of the compressed air clean gas entering the main body of the breathing mask in real time; when the gas concentration detector feeds back that the gas concentration in the high-efficiency filtration purification chamber exceeds the set value, the controller sends out an alarm signal and controls the closing of the air inlet switch and the electric control valve. At this time, the tunnel boring machine driver breathes through the activated carbon composite high-efficiency filter membrane filtration mechanism installed on the main body of the breathing mask;

[0025] During the tunneling operation of the tunnel boring machine, the thermal switch is in the open state in the initial state. The heat energy generated by the tunneling operation of the tunneling head is transferred through the filling thermal conductive coating. The pressure gas working medium of the elastic airbag Ⅰ inside the tunneling head expands in volume after absorbing heat, so that the elastic airbag Ⅰ pushes the piston Ⅰ of the piston cylinder Ⅰ and drives the piston Ⅱ of the piston cylinder Ⅱ to move backward through the piston connecting rod. While the piston Ⅱ moves backward, it compresses the elastic airbag Ⅱ. When the air pressure sensor in the elastic airbag Ⅱ feeds back that the air pressure in the elastic airbag Ⅱ reaches the set value, the controller controls the electronically controlled thermal phase change mechanism to perform heat absorption phase change, so that the pressure gas working medium of the elastic airbag Ⅰ is reduced in volume after absorbing heat. At the same time, the controller controls the closing of the thermal conductive switch. The heat energy generated by the tunneling operation of the tunnel boring head is transferred to the inner cavity of the air storage mechanism through the filling thermal conductive coating, so that the pressure gas working medium of the elastic airbag Ⅱ absorbs heat and then The volume expands, and the elastic airbag II pushes the piston II of the piston cylinder II to move forward through the piston connecting rod, and drives the piston I of the piston cylinder I to move forward together. When the air pressure sensor in the elastic airbag II feeds back that the air pressure in the elastic airbag II reaches the set value, the controller controls the electronically controlled thermal phase change mechanism to perform an exothermic phase change, so that the pressure gas working medium of the elastic airbag I expands in volume after absorbing heat again. At the same time, the controller controls to open the thermal conduction switch, and the pressure gas working medium of the elastic airbag II shrinks in volume after cooling down. The elastic airbag I pushes the piston I of the piston cylinder I again through the piston connecting rod to drive the piston II of the piston cylinder II to move backward together, and so on, to realize the back-and-forth reciprocating movement of the piston connecting rod. During the back-and-forth reciprocating movement of the piston connecting rod, the magnetic flux lines of the magnetic induction coil are cut, and the generated electrical energy is input through the wire and stored in the power storage mechanism, and supplies electrical energy to the main control box.

[0026] As a further improvement of the present invention, the electrically-controlled thermal phase change mechanism is provided in two groups, one group is provided in contact with the elastic airbag I, or in the elastic airbag I, and the other group is provided in contact with the elastic airbag II, or in the elastic airbag II. By controlling the alternating endothermic phase change and exothermic phase change of the two groups of electrically-controlled thermal phase change mechanisms, the coordinated action of the elastic airbag I and the elastic airbag II can be controlled.

[0027] Compared with the prior art, the low-energy consumption tunnel boring machine driver position compressed air breathing protection system has the following beneficial effects:

[0028] 1. The breathing detection intelligent chip equipped in the compressed air breathing protection part of the present invention can monitor the breathing condition of the tunnel boring machine driver in real time, and can adjust the working state of the air volume control mechanism according to actual needs to provide an appropriate amount of purified air, ensure the tunnel boring machine driver's breathing comfortably, and prevent energy waste caused by excessive ventilation.

[0029] 2. The compressed air breathing protection part of the present invention integrates a compressed air filtering device and a compressed air breathing mask, which can effectively filter rust residue particles and harmful gases in the compressed air, ensuring the breathing safety of the tunnel boring machine driver in a complex environment; at the same time, the gas concentration detector can monitor the gas concentration in the compressed air in real time and issue a timely warning, further improving safety.

[0030] 3. The present invention recovers the heat energy generated during the excavation of the tunnel boring machine by means of the tunnel boring machine energy recovery part arranged on the tunnel boring work device, and converts the heat energy into electrical energy for application to the respiratory protection system at the tunnel boring machine driver position, thereby reducing dependence on external power supply and improving overall energy efficiency.

[0031] 4. The energy recovery part of the tunnel boring machine of the present invention can control the high-temperature working environment by utilizing a thermal conductive coating, a thermal insulating coating and an electrically controlled thermal phase change mechanism according to the working state of the tunnel boring machine in a harsh environment, thereby ensuring the stable operation of the tunnel boring machine equipment under complex working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the structure of the tunnel boring machine in the tunneling operation state;

[0033] Figure 2 It is a schematic diagram of the external structure of the excavation working device of the present invention;

[0034] Figure 3 The diagram is a schematic diagram of the self-generating process of the tunneling working device of the tunneling machine during the tunneling operation, wherein (a) is a schematic diagram of the structure in which the elastic airbag I pushes the piston I of the piston cylinder I to drive the piston II of the piston cylinder II to move backward through the piston connecting rod, and (b) is a schematic diagram of the structure in which the elastic airbag II pushes the piston II of the piston cylinder II to drive the piston I of the piston cylinder I to move forward through the piston connecting rod;

[0035] Figure 4 3. It is a schematic diagram of the three-dimensional structure of the compressed air breathing mask of the present invention from the outer side view;

[0036] Figure 5 It is a schematic diagram of the three-dimensional structure of the compressed air breathing mask of the present invention from the inner side view;

[0037] Figure 6 It is a three-dimensional structural schematic diagram of the compressed air filtering device of the present invention.

[0038] In the figure: 1. main body of the tunnel boring machine, 2. tunnel boring working device, 21. tunnel boring head, 211. filling heat conductive coating, 212. heat insulating coating, 22. piston mechanism, 221. piston cylinder I, 222. piston cylinder II, 223. piston connecting rod, 224. piston connecting rod guide structure, 23. air storage mechanism, 231. air pressure sensor, 24. reserve power mechanism, 25. support mechanism, 26. magnetic induction coil, 271. elastic airbag I, 272. elastic airbag II, 28. heat conductive valve, 29. electronically controlled thermal phase change mechanism, 3. compressed air breathing mask , 31. Respiratory mask body, 32. Activated carbon composite high-efficiency filter membrane filtration mechanism, 33. Adjustable mask strap, 34. Respiratory detection intelligent chip, 35. Air volume control mechanism, 36. Mask connecting pipe, 37. Air inlet switch, 4. Compressed air filtration device, 41. Oil-water separator, 42. High-efficiency filtration purification chamber, 43. Gas double purifier, 44. Protection box, 45. Clean gas transmission pipeline, 46. Electric control valve, 47. Gas concentration detector, 5. Air guide pipe, 6. Main control box, 7. Tunneling machine driver, 8. Tunnel, 9. High-pressure gas pipeline. DETAILED DESCRIPTION

[0039] Since the energy consumption of the tunnel boring machine is large, how to recover and utilize the energy during the tunnel boring process of the tunnel boring machine is a problem of concern in the industry. However, the energy recovery and utilization methods in the prior art are usually based on the operating characteristics of the operating machine. For example, since the boom of the excavator needs to be frequently raised and lowered during the excavation process to excavate and lift the earth, the energy recovery and utilization method for the excavator is usually to recover the potential energy of the boom to apply to the lifting of the boom, and the energy recovery method is usually to perform hydraulic energy storage in the hydraulic system. For the tunnel boring machine, although the tunnel boring work device of the tunnel boring machine also has an operation mode of lifting and moving during the tunnel boring operation, the purpose and effect of the tunnel boring work device of the tunnel boring machine is to crush rocks, not to lift the earth of the excavator, and the lifting amplitude of the tunnel boring work device of the tunnel boring machine is much smaller than the lifting amplitude of the boom of the excavator. Therefore, the method of recovering the potential energy of the boom of the excavator is not suitable for the tunnel boring machine. The present invention recovers the heat energy generated during the tunnel boring process of the tunnel boring machine, and converts the heat energy into electrical energy and applies it to the breathing protection system of the tunnel boring machine driver position to achieve energy reduction.

[0040] The present invention will be further described below in conjunction with the accompanying drawings (hereinafter referred to as Figure 2 , Figure 3 The left and right directions are described as the front-back directions).

[0041] The tunnel boring machine includes a tunnel boring machine body 1 and a tunnel boring machine working device 2 installed on the tunnel boring machine body 1. The tunnel boring machine working device 2 is installed on the tunnel boring machine body 1 as a whole through a supporting mechanism 25. The tunnel boring machine working device 2 includes a tunnel boring head 21. The low-energy consumption tunnel boring machine driver's position compressed air breathing protection system includes a compressed air breathing protection part, a tunnel boring machine energy recovery part arranged on the tunnel boring machine working device 2, and a main control box 6 arranged on the tunnel boring machine body 1.

[0042] like Figure 1 As shown, the compressed air breathing protection part includes a compressed air breathing mask 3, a compressed air filtering device 4 and a high-pressure air pipeline 9;

[0043] like Figure 4 , Figure 5 As shown, the compressed air breathing mask 3 includes a breathing mask body 31, an activated carbon composite high-efficiency filter membrane filtering mechanism 32, an adjustable mask strap 33, a breathing detection intelligent chip 34, an air volume control mechanism 35 and a mask connecting pipe 36; the activated carbon composite high-efficiency filter membrane filtering mechanism 32 is installed on the breathing mask body 31, and is used to filter the dust gas from the external working environment entering the breathing mask body 31. The activated carbon composite high-efficiency filter membrane filtering mechanism 32 can be set to two pieces symmetrically relative to the breathing mask body 31; the adjustable The mask belt 33 is installed on the breathing mask body 31, and is used for the tunnel boring machine driver 7 to wear the breathing mask body 31; the breathing detection intelligent chip 34 is arranged inside the breathing mask body 31, and is used to detect the breathing state of the tunnel boring machine driver 7; the air volume control mechanism 35 including the electric control flow regulating valve is arranged inside the mask connecting pipe 36 connected to the breathing mask body 31, and is used to control the flow of the compressed air clean gas entering the breathing mask body 31 through the mask connecting pipe 36, and the mask connecting pipe 36 is also provided with an air inlet switch 37;

[0044] The compressed air filter device 4 is fixedly mounted on the tunnel wall of the tunnel 8 through an external protection box 44. Figure 6As shown, the compressed air filtering device 4 includes an oil-water separator 41, a high-efficiency filtering and purifying chamber 42, a gas double purifier 43, a clean gas delivery pipeline 45, an electric control valve 46 and a gas concentration detector 47; the input end of the oil-water separator 41 is connected to the high-pressure gas pipeline 9, the high-pressure gas pipeline 9 is connected to the compressed air delivery pipeline of the mine ventilation system, the output end of the oil-water separator 41 is connected to the output end of the high-efficiency filtering and purifying chamber 42, the output end of the high-efficiency filtering and purifying chamber 42 is connected to the input end of the electric control valve 46 through the clean gas delivery pipeline 45, and the gas double purifier 43 is connected to the clean gas delivery pipeline 45. The input end of the heavy purifier 43 is connected to the output end of the electric control valve 46, the output end of the gas double purifier 43 is connected to the mask connecting pipe 36 of the compressed air breathing mask 3 through the air guide tube 5, the gas concentration detector 47 is arranged in the high-efficiency filtration purification chamber 42, the high-efficiency filtration purification chamber 42 is provided with an activated carbon composite high-efficiency filter membrane, the gas double purifier 43 is provided with an ultraviolet disinfection mechanism and a sterilizing filter net, the oil-water separator 41, the activated carbon composite high-efficiency filter membrane, the ultraviolet disinfection mechanism and the sterilizing filter net are all existing technologies and will not be described in detail here.

[0045] like Figure 2 , Figure 3 As shown, the energy recovery part of the tunnel boring machine includes a piston mechanism 22, an air storage mechanism 23, an electric energy storage mechanism 24, a magnetic induction coil 26, a heat storage mechanism, a thermal switch 28 and an electrically controlled thermal phase change mechanism 29;

[0046] The rear end of the boring head 21 with a hollow inner cavity structure is coaxially fixedly installed and connected with the front end of the piston mechanism 22 with a sleeve structure, and the rear end of the piston mechanism 22 with a sleeve structure is coaxially fixedly installed and connected with the barrel mouth end of the air storage mechanism 23 with a barrel structure. The inner cavity of the boring head 21, the inner cavity of the piston mechanism 22 and the inner cavity of the air storage mechanism 23 together form a closed vacuum space;

[0047] The tunneling head 21 is provided with an elastic airbag I 271, and the elastic airbag I 271 is filled with a pressurized gas working medium. The air storage mechanism 23 is provided with an elastic airbag II 272, and the elastic airbag II 272 is filled with a pressurized gas working medium. The pressurized gas working medium is a gas with a high thermal conductivity such as hydrogen or helium, preferably helium. The air storage mechanism 23 also includes an air pressure sensor 231 arranged in the elastic airbag II 272. The piston mechanism 22 is coaxially fixed with a piston cylinder I 221 and a piston cylinder II 222 symmetrically front and back, and the piston I in the piston cylinder I 221 and the piston II in the piston cylinder II 222 are coaxially fixedly installed and connected through a piston connecting rod 223. In order to ensure the stability of the piston connecting rod 223 and coaxially move along the front and back directions to prevent eccentric loading, the piston connecting rod 223 can be fixedly arranged along the front and back directions. The piston connecting rod guide structure 224 in the shaft sleeve structure of the piston mechanism 22 is connected to the piston mechanism 22. The piston connecting rod guide structure 224 can be a guide rail arranged in the shaft sleeve structure of the piston mechanism 22 and a guide wheel structure arranged on the piston connecting rod 223, or a slide rail arranged in the shaft sleeve structure of the piston mechanism 22 and a slider structure arranged on the piston connecting rod 223. Other linear displacement guide structures, the front end of the piston I of the piston cylinder I 221 is transmission-connected with the elastic airbag I 271, and the rear end of the piston II of the piston cylinder II 222 is transmission-connected with the elastic airbag II 272. In order to achieve a better thermal expansion transmission effect, the front end of the piston I of the piston cylinder I 221 can be coaxially arranged with the elastic airbag I 271, and the rear end of the piston II of the piston cylinder II 222 can be coaxially arranged with the elastic airbag II 272;

[0048] The magnetic induction coil 26 is coaxially fixedly arranged inside or outside the piston mechanism 22, and the magnetic induction coil 26 is in a state of being sleeved on the outside of the piston connecting rod 223. The electric energy storage mechanism 24 including the charging and discharging circuit and the rechargeable battery is installed on the main body of the tunneling machine, and the two ends of the piston connecting rod 223 are electrically connected to the electric energy storage mechanism 24 through wires.

[0049] The heat storage mechanism includes a filled heat-conductive coating 211 and a heat-insulating coating 212. The filled heat-conductive coating 211 including a high heat-conductive material such as asphalt-based carbon fiber, graphene fiber, graphene composite carbon fiber, etc. is arranged on the inner surfaces of the tunneling head 21 and the piston mechanism 22, and the filled heat-conductive coating 211 on the inner surface of the tunneling head 21 and the filled heat-conductive coating 211 on the inner surface of the piston mechanism 22 are connected through a heat-conductive switch 28. The heat-insulating coating 212 including a heat-insulating material such as nanoporous aerogel, glass wool, rock wool, etc. is at least arranged on the outer surface of the piston mechanism 22. In order to achieve a better effect of controlling the conduction of heat to the inside, a wear-resistant heat-insulating coating including a wear-resistant heat-insulating material such as ceramic fiber, nano-ceramic microbeads, and a composite material made of ceramic fiber and a resin matrix can be arranged on the outer surface of the tunneling head 21 except the knife seat.

[0050] The electrically controlled thermal phase change mechanism 29 is arranged in contact with the elastic airbag Ⅰ271, or the electrically controlled thermal phase change mechanism 29 is arranged in the elastic airbag Ⅰ271. The electrically controlled thermal phase change mechanism 29 is provided with thermal phase change materials such as molten salt phase change materials, organic phase change materials, alloy phase change materials, etc. It is an existing technology to control the phase change of thermal phase change materials by electrical control, which will not be described in detail here.

[0051] The main control box 6 includes a controller, which is electrically connected to the breathing detection intelligent chip 34, the electrically controlled flow regulating valve of the air volume control mechanism 35, the air inlet switch 37, the ultraviolet disinfection mechanism of the gas double purifier 43, the electrically controlled valve 46, the gas concentration detector 47, the electric energy storage mechanism 24, the air pressure sensor 231, the thermal conductivity switch 28 and the electrically controlled thermal phase change mechanism 29.

[0052] Working principle of this low-energy tunnel boring machine driver's position compressed air breathing protection system:

[0053] Before starting the tunnel boring machine, ensure that the compressed air delivery pipeline of the mine ventilation system is connected to the high-pressure gas pipeline 9, so that the high-pressure gas pipeline 9 can continuously and stably supply pressurized air. After the tunnel boring machine driver 7 puts on the breathing mask body 31, the main control box 6 is started. The controller controls the start-up of the electric control flow regulating valve of the air volume control mechanism 35, the air inlet switch 37, the ultraviolet disinfection mechanism of the gas double purifier 43, the electric control valve 46, the gas concentration detector 47 and the air pressure sensor 231;

[0054] 1. Compressed air breathing protection: The compressed air in the high-pressure gas pipeline 9 is separated and purified by oil and water in the oil-water separator 41 and then enters the high-efficiency filtration purification chamber 42. The gas concentration detector 47 feeds back the gas concentration data in the high-efficiency filtration purification chamber 42 to the controller in real time. The activated carbon composite high-efficiency filter membrane in the high-efficiency filtration purification chamber 42 finely filters and purifies the compressed air and then enters the gas double purifier 43 through the clean gas delivery pipeline 45 and the electric control valve 46. The ultraviolet disinfection mechanism and the sterilizing filter net in the gas double purifier 43 sterilize and filter the compressed air and then enter the breathing mask body 3 after depressurization through the air guide pipe 5, the air volume control mechanism 35, the mask connecting pipe 36 and the air inlet switch 37. 1. The breathing detection smart chip 34 feeds back the inhalation data of the tunnel boring machine driver 7 to the controller in real time; when the breathing detection smart chip 34 feeds back that the inhalation data of the tunnel boring machine driver 7 exceeds the set range, the controller controls the electric control flow regulating valve of the air volume control device 35 to adjust the flow of the compressed clean gas entering the breathing mask body 31 in real time; when the gas concentration detector 47 feeds back that the gas concentration in the high-efficiency filtration purification chamber 42 exceeds the set value, the controller sends out an alarm signal and controls the closing of the air inlet switch 37 and the electric control valve 46. At this time, the tunnel boring machine driver 7 can use the activated carbon composite high-efficiency filter membrane filtration mechanism 32 installed on the breathing mask body 31 to ensure breathing safety for a long time underground;

[0055] 2. Energy recovery of the tunnel boring machine: During the tunnel boring operation of the tunnel boring machine, the thermal switch 28 is in the open state in the initial state. Figure 3 As shown in (a), the heat energy generated by the tunneling operation of the tunneling head 21 is transferred through the filling heat conductive coating 211. Since the heat conductive switch 28 is in the open state, the heat energy generated by the tunneling operation of the tunneling head 21 can only be transferred in the inner cavity of the tunneling head 21, and cannot be transferred to the inner cavity of the piston mechanism 22 and the inner cavity of the air storage mechanism 23. The pressure gas working medium of the elastic airbag Ⅰ 271 located inside the tunneling head 21 expands in volume after absorbing heat, so that the elastic airbag Ⅰ 271 pushes the piston Ⅰ of the piston cylinder Ⅰ 221 through The piston connecting rod 223 drives the piston II of the piston cylinder II 222 to move backwards together. The piston II moves backwards while compressing the elastic airbag II 272. When the air pressure sensor 231 in the elastic airbag II 272 feedbacks that the air pressure in the elastic airbag II 272 reaches the set value, the controller controls the electrically controlled thermal phase change mechanism 29 to make the thermal phase change material undergo an endothermic phase change, so that the pressure gas working medium of the elastic airbag I 271 is reduced in volume after being absorbed by the thermal phase change material. At the same time, the controller controls the closed thermal conductive switch 28. Figure 3 As shown in (b), the heat energy generated by the excavation operation of the excavation head 21 is transferred to the inner cavity of the air storage mechanism 23 through the filling heat-conducting coating 211, so that the pressure gas working medium of the elastic airbag II 272 expands in volume after absorbing heat, and the elastic airbag II 272 pushes the piston II of the piston cylinder II 222 to drive the piston I of the piston cylinder I 221 to move forward together through the piston connecting rod 223. When the air pressure sensor 231 in the elastic airbag II 272 feeds back that the air pressure in the elastic airbag II 272 reaches the set value, the controller controls the electronically controlled thermal phase change mechanism 29 to make the thermal phase change material undergo an exothermic phase change, so that the pressure gas working medium of the elastic airbag I 271 expands in volume after absorbing heat again. At the same time, the controller controls the opening and closing mechanism 29. The heat conduction switch 28 is turned on to cut off the heat transfer channel from the heat energy generated by the tunneling operation of the tunneling head 21 to the air storage mechanism 23, so that the pressure gas working fluid of the elastic airbag II 272 is cooled and its volume is reduced. The elastic airbag I 271 then pushes the piston I of the piston cylinder I 221 again to drive the piston II of the piston cylinder II 222 to move backward through the piston connecting rod 223, and so on, to achieve the back-and-forth reciprocating movement of the piston connecting rod 223. During the back-and-forth reciprocating movement of the piston connecting rod 223, the magnetic flux lines of the magnetic induction coil 26 are cut, and the generated electric energy is input through the wire and stored in the electric energy storage mechanism 24, and supplies electric energy to the main control box 6, so as to realize the recycling of the heat generated during the tunneling process of the tunneling machine.

[0056] In order to achieve better energy recovery and utilization effects, as a further improvement of the present invention, the electrically-controlled thermal phase change mechanism 29 can be set into two groups, one group is set against the elastic airbag I 271, or is set in the elastic airbag I 271, and the other group is set against the elastic airbag II 272, or is set in the elastic airbag II 272. By controlling the alternating endothermic phase change and exothermic phase change of the two groups of electrically-controlled thermal phase change mechanisms 29, the coordinated action of the elastic airbag I 271 and the elastic airbag II 272 can be controlled, thereby achieving the control of the piston connecting rod 223 to move back and forth at a speed that is basically consistent.

[0057] The present invention can supply purified air treated by a compressed air filter device 4 to the driver of the tunnel boring machine through a compressed air breathing mask 3 through the compressed air breathing protection part, and can effectively filter rust residue particles and harmful gases in the compressed air to ensure the breathing safety of the tunnel boring machine driver in a complex environment; through the tunnel boring machine energy recovery part, it can recover the heat energy generated during the tunnel boring machine excavation process and convert it into electrical energy to power the respiratory protection system, which can not only reduce the energy consumption of the respiratory protection system, but also greatly alleviate the problems of high working environment temperature and high labor intensity of operators caused by the accumulation of a large amount of heat energy during the tunnel boring machine excavation operation.

Claims

1. A low-energy consumption tunnel boring machine driver position compressed air breathing protection system, characterized in that: It includes a compressed air breathing protection part and a main control box (6); The compressed air breathing protection part comprises a compressed air breathing mask (3), a compressed air filtering device (4) and a high-pressure air pipeline (9); The compressed air breathing mask (3) comprises a breathing mask body (31), an activated carbon composite high-efficiency filter membrane filtering mechanism (32), an adjustable mask belt (33), a breathing detection intelligent chip (34), an air volume control mechanism (35) and a mask connecting pipe (36); the activated carbon composite high-efficiency filter membrane filtering mechanism (32) and the adjustable mask belt (33) are respectively mounted on the breathing mask body (31); the breathing detection intelligent chip (34) is arranged inside the breathing mask body (31); An air volume control mechanism (35) including an electrically controlled flow regulating valve is arranged inside a mask connecting pipe (36) connected to the breathing mask body (31), and an air inlet switch (37) is also arranged on the mask connecting pipe (36); The compressed air filtering device (4) is fixedly installed on the tunnel wall of the tunnel (8), and the compressed air filtering device (4) comprises an oil-water separator (41), a high-efficiency filtering and purification chamber (42), a gas double purifier (43), a clean gas delivery pipeline (45), an electric control valve (46) and a gas concentration detector (47); the input end of the oil-water separator (41) is connected to the high-pressure gas pipeline (9), the high-pressure gas pipeline (9) is connected to the compressed air delivery pipeline of the mine ventilation system, the output end of the oil-water separator (41) is connected to the output end of the high-efficiency filtering and purification chamber (42), and the high-efficiency filtering and purification chamber (45) is connected to the compressed air delivery pipeline of the mine ventilation system. The output end of the gas double purifier (43) is connected to the input end of the electric control valve (46) through the clean gas delivery pipeline (45), the input end of the gas double purifier (43) is connected to the output end of the electric control valve (46), the output end of the gas double purifier (43) is connected to the mask connecting pipe (36) of the compressed air breathing mask (3) through the air guide pipe (5), the gas concentration detector (47) is arranged in the high-efficiency filtering and purification chamber (42), the high-efficiency filtering and purification chamber (42) is provided with an activated carbon composite high-efficiency filter membrane, and the gas double purifier (43) is provided with an ultraviolet disinfection mechanism and a sterilizing filter net; The main control box (6) includes a controller, which is electrically connected to the breathing detection intelligent chip (34), the electric control flow regulating valve of the air volume control mechanism (35), the air inlet switch (37), the ultraviolet disinfection mechanism of the gas double purifier (43), the electric control valve (46) and the gas concentration detector (47).

2. According to the low-energy consumption tunnel boring machine driver position compressed air breathing protection system of claim 1, the tunnel boring machine comprises a tunnel boring machine body (1) and a tunnel boring work device (2) installed on the tunnel boring machine body (1), the tunnel boring work device (2) is installed on the tunnel boring machine body (1) as a whole through a supporting mechanism (25), and the tunnel boring work device (2) comprises a tunnel boring head (21), characterized in that: The low-energy consumption tunnel boring machine driver position compressed air type respiratory protection system also includes a tunnel boring machine energy recovery part arranged on the tunnel boring work device (2); a main control box (6) is arranged on the tunnel boring machine body (1); The energy recovery part of the tunnel boring machine comprises a piston mechanism (22), an air storage mechanism (23), an electric energy storage mechanism (24), a magnetic induction coil (26), a heat storage mechanism, a heat conduction switch (28) and an electrically controlled thermal phase change mechanism (29); The rear end of the boring head (21) having a hollow inner cavity structure is coaxially fixedly connected to the front end of the piston mechanism (22) having a sleeve structure, and the rear end of the piston mechanism (22) having a sleeve structure is coaxially fixedly connected to the barrel mouth of the air storage mechanism (23) having a barrel structure, and the inner cavity of the boring head (21), the inner cavity of the piston mechanism (22) and the inner cavity of the air storage mechanism (23) together enclose a closed vacuum space; An elastic airbag I (271) is provided in the tunneling head (21), and the elastic airbag I (271) is filled with a pressurized gas medium; an elastic airbag II (272) is provided in the air storage mechanism (23), and the elastic airbag II (272) is filled with a pressurized gas medium; the air storage mechanism (23) further comprises an air pressure sensor (231) arranged in the elastic airbag II (272); a piston cylinder I (221) and a piston cylinder II (222) are coaxially and symmetrically fixed in the piston mechanism (22); the piston I in the piston cylinder I (221) and the piston II in the piston cylinder II (222) are coaxially and fixedly connected via a piston connecting rod (223); the piston I of the piston cylinder I (221) is transmission-connected to the elastic airbag I (271), and the piston II of the piston cylinder II (222) is transmission-connected to the elastic airbag II (272); The magnetic induction coil (26) is coaxially fixedly arranged inside or outside the piston mechanism (22), and the magnetic induction coil (26) is in a state of being sleeved on the outside of the piston connecting rod (223). The electric energy storage mechanism (24) including a charging and discharging circuit and a rechargeable battery is installed on the main body of the tunneling machine, and the two ends of the piston connecting rod (223) are respectively electrically connected to the electric energy storage mechanism (24) through wires; The heat storage mechanism comprises a filling heat-conducting coating (211) and a heat-insulating coating (212); the filling heat-conducting coating (211) comprising a heat-conducting material is arranged on the inner surface of the closed vacuum space, and the filling heat-conducting coating (211) on the inner surface of the boring head (21) and the filling heat-conducting coating (211) on the inner surface of the piston mechanism (22) are connected via a heat-conducting switch (28); the heat-insulating coating (212) comprising a heat-insulating material is at least arranged on the outer surface of the piston mechanism (22); The electrically controlled thermal phase change mechanism (29) is arranged close to the elastic airbag I (271), or the electrically controlled thermal phase change mechanism (29) is arranged inside the elastic airbag I (271), and a thermal phase change material is arranged inside the electrically controlled thermal phase change mechanism (29); The electric energy storage mechanism (24), the air pressure sensor (231), the thermal conductivity switch (28) and the electrically controlled thermal phase change mechanism (29) are electrically connected to the controller of the main control box (6) respectively.

3. The low-energy consumption tunnel boring machine driver position compressed air breathing protection system according to claim 2 is characterized in that: The electrically controlled thermal phase change mechanism (29) is provided in two groups, one group being arranged close to the elastic airbag I (271) or arranged in the elastic airbag I (271), and the other group being arranged close to the elastic airbag II (272) or arranged in the elastic airbag II (272).

4. The low-energy tunnel boring machine driver position compressed air breathing protection system according to claim 2 is characterized in that: The piston connecting rod (223) is connected to the piston mechanism (22) via a piston connecting rod guide structure (224) fixedly arranged in the shaft sleeve structure of the piston mechanism (22) along the front-rear direction.

5. The low-energy consumption tunnel boring machine driver position compressed air breathing protection system according to claim 2, characterized in that: The front end of the piston I of the piston cylinder I (221) is coaxially arranged with the elastic airbag I (271), and the rear end of the piston II of the piston cylinder II (222) is coaxially arranged with the elastic airbag II (272).

6. The low-energy consumption tunnel boring machine driver position compressed air breathing protection system according to claim 2, characterized in that: The heat-conducting material filling the heat-conducting coating (211) is asphalt-based carbon fiber, or graphene fiber, or graphene composite carbon fiber; the heat-insulating material of the heat-insulating coating (212) is nanoporous aerogel, or glass wool, or rock wool; the heat phase change material in the electrically controlled heat phase change mechanism (29) is a molten salt phase change material, or an organic phase change material, or an alloy phase change material.

7. The low-energy consumption tunnel boring machine driver position compressed air breathing protection system according to claim 2, characterized in that: The pressurized gas working fluid is hydrogen or helium.

8. A low-energy tunnel boring machine driver position compressed air breathing protection method based on the low-energy tunnel boring machine driver position compressed air breathing protection system as claimed in claim 1, characterized in that: Before the tunnel boring machine is started, it is ensured that the compressed air delivery pipeline of the mine ventilation system is connected to the high-pressure gas pipeline (9), and the tunnel boring machine driver (7) wears the breathing mask body (31) and starts the main control box (6), and the controller controls the start-up of the electric control flow regulating valve of the air volume control mechanism (35), the air inlet switch (37), the ultraviolet disinfection mechanism of the gas double purifier (43), the electric control valve (46) and the gas concentration detector (47); The pressurized air in the high-pressure gas pipeline (9) is separated and purified by oil and water in the oil-water separator (41) and then enters the high-efficiency filtration purification chamber (42). The gas concentration detector (47) feeds back the gas concentration data in the high-efficiency filtration purification chamber (42) to the controller in real time. The activated carbon composite high-efficiency filter membrane in the high-efficiency filtration purification chamber (42) finely filters and purifies the pressurized air and then enters the gas double purifier (43) through the clean gas delivery pipeline (45) and the electric control valve (46). The ultraviolet disinfection mechanism and the sterilizing filter net in the gas double purifier (43) sterilize and filter the pressurized air and then enter the breathing mask body (31) after the pressure is reduced through the air guide pipe (5), the air volume control mechanism (35), the mask connecting pipe (36) and the air inlet switch (37). The breathing detection intelligent chip (34) feeds back the inhalation volume data of the tunnel boring machine driver (7) to the controller in real time. When the breathing detection smart chip (34) feedbacks that the inhaled air volume of the tunnel boring machine driver (7) exceeds the set range, the controller controls the electric control flow regulating valve of the air volume control device (35) to adjust the flow of the compressed clean air entering the breathing mask body (31) in real time; When the gas concentration detector (47) feeds back that the gas concentration in the high-efficiency filtering and purification chamber (42) exceeds the set value, the controller sends out an alarm signal and controls the closing of the air inlet switch (37) and the electric control valve (46). At this time, the tunnel boring machine driver (7) breathes through the activated carbon composite high-efficiency filter membrane filtering mechanism (32) installed on the breathing mask body (31).

9. A low-energy tunnel boring machine driver position compressed air breathing protection method based on the low-energy tunnel boring machine driver position compressed air breathing protection system as claimed in claim 2, characterized in that: Before starting the tunnel boring machine, ensure that the compressed air delivery pipeline of the mine ventilation system is connected to the high-pressure gas pipeline (9), and the tunnel boring machine driver (7) wears the breathing mask body (31) and starts the main control box (6). The controller controls the start-up of the electric control flow regulating valve of the air volume control mechanism (35), the air inlet switch (37), the ultraviolet disinfection mechanism of the gas double purifier (43), the electric control valve (46), the gas concentration detector (47) and the air pressure sensor (231); The pressurized air in the high-pressure gas pipeline (9) is separated and purified by oil and water in the oil-water separator (41) and then enters the high-efficiency filtration purification chamber (42). The gas concentration detector (47) feeds back the gas concentration data in the high-efficiency filtration purification chamber (42) to the controller in real time. The activated carbon composite high-efficiency filter membrane in the high-efficiency filtration purification chamber (42) finely filters and purifies the pressurized air and then enters the gas double purifier (43) through the clean gas delivery pipeline (45) and the electric control valve (46). The ultraviolet disinfection mechanism and the sterilization filter net in the gas double purifier (43) sterilize and filter the pressurized air and then enter the breathing mask body after the pressure is reduced through the air guide pipe (5), the air volume control mechanism (35), the mask connecting pipe (36) and the air inlet switch (37). (31), the breathing detection smart chip (34) feeds back the inhalation volume data of the tunnel boring machine driver (7) to the controller in real time; when the breathing detection smart chip (34) feeds back that the inhalation volume of the tunnel boring machine driver (7) exceeds the set range, the controller controls the electric control flow regulating valve of the air volume control device (35) to adjust the flow of the compressed clean gas entering the breathing mask body (31) in real time; when the gas concentration detector (47) feeds back that the gas concentration in the high-efficiency filtration purification chamber (42) exceeds the set value, the controller sends out an alarm signal and controls the closing of the air inlet switch (37) and the electric control valve (46), and at this time the tunnel boring machine driver (7) breathes through the activated carbon composite high-efficiency filter membrane filtration mechanism (32) installed on the breathing mask body (31); During the tunneling operation of the tunneling machine, the heat conduction switch (28) is in the open state in the initial state, and the heat energy generated by the tunneling operation of the tunneling head (21) is transferred through the filling heat conduction coating (211). The pressure gas working medium in the elastic airbag I (271) inside the tunneling head (21) absorbs heat and expands in volume, so that the elastic airbag I (271) pushes the piston I of the piston cylinder I (221) through the piston connecting rod (223) to drive the piston II of the piston cylinder II (222) to move backwards together. When the piston II moves backwards, the elastic airbag II (272) is compressed. When the air pressure sensor (231) in the elastic airbag II (272) feeds back that the air pressure in the elastic airbag II (272) reaches a set value, the controller controls the electrically controlled thermal phase change mechanism (29) to perform an endothermic phase change, so that the pressure gas working medium in the elastic airbag I (271) absorbs heat and its volume is reduced. At the same time, the controller controls the closing thermal conduction switch (28), so that the heat energy generated by the excavation operation of the excavation head (21) is transferred to the inner cavity of the air storage mechanism (23) through the filling thermal conductive coating (211), so that the pressure gas working medium in the elastic airbag II (272) absorbs heat and its volume is reduced. The elastic airbag II (272) pushes the piston II of the piston cylinder II (222) through the piston connecting rod (223), driving the piston I of the piston cylinder I (221) to move forward. When the air pressure sensor (231) in the elastic airbag II (272) feeds back that the air pressure in the elastic airbag II (272) reaches the set value, the controller controls the electrically controlled thermal phase change mechanism (29) to perform heat release phase change, so that the pressure gas working medium in the elastic airbag I (271) absorbs heat again and expands in volume. At the same time, the controller controls the opening of the thermal switch (28) and the elastic airbag (271). After the pressure gas working medium in bag II (272) is cooled, its volume is reduced, and the elastic air bag I (271) pushes the piston I of the piston cylinder I (221) again, and drives the piston II of the piston cylinder II (222) to move backward through the piston connecting rod (223), and so on, to achieve the forward and backward reciprocating cyclic movement of the piston connecting rod (223). During the forward and backward reciprocating cyclic movement, the piston connecting rod (223) cuts the magnetic flux lines of the magnetic induction coil (26), and the generated electric energy is input through the wire and stored in the electric energy storage mechanism (24), and supplies electric energy to the main control box (6).

10. The compressed air breathing protection method for the driver of a low-energy tunnel boring machine according to claim 9, characterized in that: The electrically controlled thermal phase change mechanism (29) is provided in two groups, one group is provided close to the elastic airbag I (271) or in the elastic airbag I (271), and the other group is provided close to the elastic airbag II (272) or in the elastic airbag II (272); The coordinated action of the elastic airbag I (271) and the elastic airbag II (272) is controlled by controlling the alternating endothermic phase change and exothermic phase change of the two sets of electrically controlled thermal phase change mechanisms (29).

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