Sludge-based biochar production equipment

Abstract

The invention discloses sludge-based biochar production equipment, and relates to the field of biochar production. Sludge-based biochar production equipment comprises a supporting base, and further comprises an electric heating cylinder rotationally connected to the supporting base, and an air cylinder rotationally connected to the supporting base, one end of the electric heating cylinder is provided with an opening, and the other end of the electric heating cylinder is provided with an air outlet; the cover plate is rotationally connected to the electric heating cylinder and used for closing an opening of the electric heating cylinder, and the filter cylinder is arranged in the electric heating cylinder and fixedly connected with the cover plate; in the sludge treatment process, garbage in sludge can be effectively cleaned, the sludge can be uniformly heated, water evaporation is accelerated, the water content is reduced, the quality of subsequently produced biochar is improved, heat in water vapor generated by sludge evaporation can be recycled, and the energy consumption is reduced. And the collected high-temperature gas is utilized to clean light garbage remaining on the comb plate, and the sludge is dried again, so that the waste of energy is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of biochar production, and in particular relates to a sludge-based biochar production device. Background Art

[0002] With the continuous expansion of the scale of urban sewage treatment, the output of sludge is increasing. Since sludge contains a large amount of organic matter, heavy metals and pathogens, if it is not handled properly, it will cause serious secondary pollution to the environment. Therefore, converting sludge into biochar is an effective way to utilize resources.

[0003] At present, in the process of converting sludge into biochar, the early treatment of sludge is crucial, and the quality of its treatment directly determines the quality and efficiency of subsequent biochar production;

[0004] However, conventional sludge treatment equipment has many deficiencies in dehydration. For example, when the sludge is heated and dehydrated, the sludge is in a static state in the heating cylinder, so that the sludge is heated unevenly inside and outside, thereby reducing the evaporation efficiency of water in the sludge and the dehydration rate is poor. In view of this, the present invention is proposed. Summary of the invention

[0005] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a sludge-based biochar production device that can overcome the above problems or at least partially solve the above problems.

[0006] In order to solve the above technical problems, the basic concept of the technical solution adopted by the present invention is:

[0007] A sludge-based biochar production device comprises a support base, and also includes: an electric heating cylinder rotatably connected to the support base, wherein one end of the electric heating cylinder is open; a cover plate rotatably connected to the electric heating cylinder and used to close the opening of the electric heating cylinder, a filter cylinder arranged in the electric heating cylinder and fixedly connected to the cover plate, wherein the upper end of the filter cylinder is open, a fixing rod is fixedly connected to the cover plate, and the fixing rod is detachably connected to the support base by a plurality of fixing bolts; and a plurality of comb plates are fixedly connected to the inner wall of the electric heating cylinder at equal intervals around the circumference.

[0008] Preferably, one end of the comb plate away from the inner wall of the electric heating cylinder is in contact with the outer wall of the filter cylinder.

[0009] In order to drive the electric heating tube to rotate on the support base, preferably, a motor is fixedly mounted on the support base, a gear is fixedly connected to the output end of the motor, a gear ring is fixedly mounted on the electric heating tube, and the gear is meshingly connected with the gear ring.

[0010] In order to filter and dehumidify the high-temperature water vapor discharged from the electric heating tube, preferably, a filtering and dehumidifying box is fixedly installed on the supporting base, the top of the filtering and dehumidifying box is fixedly connected with an air pipe, an exhaust pipe connected to the electric heating tube is arranged on the cover plate, and the end of the exhaust pipe away from the cover plate is connected to the filtering and dehumidifying box.

[0011] Furthermore, it also includes a desiccant layer and an activated carbon filter plate, and the desiccant layer and the activated carbon filter plate are both plugged into the filter dehumidification box.

[0012] In order to recycle the high-temperature gas after filtration and dehumidification, thereby reducing the waste of thermal energy, further, an insulated air storage box is fixedly installed on the filtration and dehumidification box, and the filtration and dehumidification box is connected to the insulated air storage box through an air supply pipe. The insulated air storage box is fixedly connected with a pressure relief pipe, and a pressure relief valve is arranged on the pressure relief pipe.

[0013] In order to clean up the garbage remaining on the comb plate, such as garbage bags and other garbage, further, a scraper is sleeved on the comb plate, an air delivery cavity is opened in the scraper, and a plurality of jet holes connected with the air delivery cavity are opened on the scraper, a hollow cavity is opened at one end of the electric heating tube, a boosting pipe 1 connected with the air delivery cavity is arranged on the scraper, and the end of the boosting pipe 1 away from the air delivery cavity is connected with the hollow cavity, a boosting pipe 2 is fixedly connected to the insulated air storage box, and the end of the boosting pipe 2 away from the insulated air storage box is connected with the hollow cavity through a rotary joint, the rotary joint is arranged on the electric heating tube and coaxially with the electric heating tube, and a solenoid valve is arranged on the boosting pipe 2.

[0014] In order to push the scraper to move on the comb plate, further, a guide rod is fixedly connected to the scraper, one end of the guide rod passes through the comb plate and is slidably connected to the electric heating tube, a limiting block is fixedly connected to the guide rod, a push block is fixedly connected to the support base, the push block is used in conjunction with the guide rod, a spring is sleeved on the guide rod, one end of the spring is fixedly connected to the limiting block, and the other end is fixedly connected to the outer wall of the electric heating tube.

[0015] Furthermore, a side of the push block facing the electric heating tube is arranged in an arc shape, and a side of the push block fixedly connected to the support base is arranged in a plane.

[0016] In order to increase the sealing performance of the connection between the cover plate and the electric heating tube, preferably, a sealing groove is provided on the electric heating tube, a sealing plug is fixedly connected to the cover plate, the sealing plug is inserted into the sealing groove, a sealing gasket is provided on the electric heating tube, and the sealing gasket fits with the cover plate.

[0017] After adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art:

[0018] The present invention intercepts and separates the garbage in the sludge by means of comb plates, firstly performs preliminary separation, and then achieves fine separation with the help of filter cartridges, which can clean out the garbage in the sludge more thoroughly and prevent impurities from affecting the quality of subsequent biochar.

[0019] When the electric heating cylinder rotates, the sludge flows inside the cylinder and absorbs heat evenly to avoid local overheating or insufficient heating. At the same time, the comb plate moves the sludge to speed up the evaporation of water, more effectively reduce the water content of the sludge, and further improve the quality of the biochar produced later.

[0020] By using a filter dehumidification box to dehumidify and purify the water vapor generated by the electric heating tube, and then collecting and storing it in a heat-insulating gas storage box, energy recycling is achieved, reducing energy waste;

[0021] With the help of high-temperature gas stored in the heat-insulating gas storage box, it is ejected through the jet holes on the scraper, which can not only clean the garbage on the comb plate, but also dry the sludge again, thus improving the energy utilization rate of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The structure of the present invention is schematically shown in FIG. Figure 1 ;

[0023] Figure 2 The structure of the present invention is schematically shown in FIG. Figure 2 ;

[0024] Figure 3 This is a front view of the electric heating tube and the supporting base of the present invention;

[0025] Figure 4 It is a cross-sectional view of the electric heating cartridge, the filter cartridge, and the filter dehumidification box of the present invention;

[0026] Figure 5 It is a cross-sectional view of the electric heating tube, the cover plate and the scraper of the present invention;

[0027] Figure 6 It is a side view of the electric heating cartridge and the filter cartridge of the present invention;

[0028] Figure 7 It is a schematic diagram of the structure of the comb plate and the scraper of the present invention;

[0029] Figure 8 It is a structural schematic diagram of the filtering and dehumidifying box and the heat-insulating air storage box of the present invention;

[0030] Fig. 9 The present invention Figure 5 A magnified view of part A;

[0031] Fig.10 The present invention Figure 5Enlarged view of part B.

[0032] In the figure: 1. support base; 101. electric heating tube; 102. cover plate; 103. sealing gasket; 104. sealing plug; 105. fixing rod; 2. filter cartridge; 201. comb plate; 3. motor; 301. gear; 302. gear ring; 4. filter dehumidification box; 401. desiccant layer; 402. activated carbon filter plate; 403. exhaust pipe; 404. insulated gas storage box; 405. gas transmission pipe; 406. pressure relief pipe; 5. scraper; 501. guide rod; 502. limit block; 503. spring; 504. push block; 6. gas transmission cavity; 601. jet hole; 602. hollow cavity; 603. boost pipe one; 604. boost pipe two; 605. rotary joint. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The following embodiments are used to illustrate the present invention but are not used to limit the scope of the present invention.

[0034] Example 1: Reference Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 6 A sludge-based biochar production device includes a support base 1, and also includes: an electric heating cylinder 101 rotatably connected to the support base 1, wherein one end of the electric heating cylinder 101 is open; a cover plate 102, rotatably connected to the electric heating cylinder 101, and used to close the opening of the electric heating cylinder 101, a filter cartridge 2, arranged in the electric heating cylinder 101, and fixedly connected to the cover plate 102, wherein the upper end of the filter cartridge 2 is open, a fixing rod 105 is fixedly connected to the cover plate 102, and the fixing rod 105 is detachably connected to the support base 1 through a plurality of fixing bolts; a plurality of comb plates 201, circumferentially equidistantly fixedly connected to the inner wall of the electric heating cylinder 101.

[0035] One end of the comb plate 201 away from the inner wall of the electric heating tube 101 is in contact with the outer wall of the filter tube 2 .

[0036] The support base 1 is fixedly mounted with a motor 3 , the output end of the motor 3 is fixedly connected with a gear 301 , the electric heating tube 101 is fixedly mounted with a gear ring 302 , and the gear 301 is meshingly connected with the gear ring 302 .

[0037] When in use, the sludge to be treated is poured into the electric heating cylinder 101 through the filling pipe provided on the cover plate 102. After pouring an appropriate amount of sludge, the sealing cover for the filling pipe is covered, and then the motor 3 and the heating device inside the electric heating cylinder 101 are started. At this time, the motor 3 drives the electric heating cylinder 101 to rotate slowly on the supporting base 1 through the meshing gear 301 and the gear ring 302. During the rotation of the electric heating cylinder 101, although the filter cartridge 2 remains stationary, the comb plate 201 on the inner wall of the electric heating cylinder 101 will rotate with the rotation of the electric heating cylinder 101. When the garbage in the sludge (such as stones, metal fragments, plastic bags, etc.) contacts the comb plate 201, it will be intercepted by it, so that the comb plate 201 can remove the garbage from the sludge. The garbage is separated out, thereby achieving preliminary separation from the sludge body, and then when the comb plate 201 rotates to a tilted downward state and corresponds to the opening of the upper end of the filter cartridge 2, the garbage intercepted on the comb plate 201 will roll into the filter cartridge 2 due to gravity. Since the surface of the garbage will inevitably carry some sludge, and since the filter cartridge 2 has a certain filtering function, the sludge particles attached to the surface of the garbage can pass through the filter holes of the filter cartridge 2 under the action of gravity and flow back into the electric heating cartridge 101 to continue to participate in the heating treatment, while the relatively large garbage remains in the filter cartridge 2, further completing the fine separation of garbage and sludge, so that the garbage in the sludge can be cleaned out more thoroughly, thereby improving the quality of the biochar produced later;

[0038] At the same time, in the process of the electric heating tube 101 heating the sludge, the water in the sludge is quickly evaporated by the heat to form water vapor, so that the water content of the sludge is reduced. At the same time, when the electric heating tube 101 rotates, the sludge can flow in the electric heating tube 101, so that the sludge can continuously change its position in the electric heating tube 101, so that the sludge absorbs heat evenly to avoid local overheating or insufficient heating. At the same time, the comb plate 201 that rotates with the electric heating tube 101 can move the sludge in the electric heating tube 101 to better flow, so that more water is exposed to the heating environment, thereby accelerating the evaporation rate of water and more effectively reducing the water content of the sludge, thereby further improving the quality of biochar in subsequent production.

[0039] Example 2: Reference Figure 1 , Figure 4 , Figure 8 , a sludge-based biochar production equipment, is basically the same as Example 1, and further, a filter dehumidification box 4 is fixedly installed on the support base 1, and a gas pipe 405 is fixedly connected to the top of the filter dehumidification box 4, and an exhaust pipe 403 connected to the electric heating cylinder 101 is provided on the cover plate 102, and the end of the exhaust pipe 403 away from the cover plate 102 is connected to the filter dehumidification box 4.

[0040] It also includes a desiccant layer 401 and an activated carbon filter plate 402 , and both the desiccant layer 401 and the activated carbon filter plate 402 are plugged into the filter dehumidification box 4 .

[0041] A heat preservation gas storage box 404 is fixedly installed on the filter dehumidification box 4, and the filter dehumidification box 4 is connected with the heat preservation gas storage box 404 through an air supply pipe 405. A pressure relief pipe 406 is fixedly connected to the heat preservation gas storage box 404, and a pressure relief valve is arranged on the pressure relief pipe 406.

[0042] In the process of the electric heating cylinder 101 heating the sludge, the water in the sludge is rapidly evaporated by the heat to form water vapor. At this time, the water vapor enters the filter dehumidification box 4 through the exhaust pipe 403. In the filter dehumidification box 4, the water vapor first passes through the desiccant layer 401. The desiccant (such as anhydrous calcium chloride, etc.) in the desiccant layer 401 absorbs the water in the water vapor, so that the water vapor is preliminarily dehumidified, and then passes through the activated carbon filter plate 402. The activated carbon filter plate 402 uses its rich pore structure to absorb the odor and a small amount of impurities carried in the water vapor, and further purifies the water vapor. The water vapor after filtration and dehumidification enters the heat preservation gas storage box 404 through the gas transmission pipe 405 for storage, so as to be recycled and utilized later, thereby reducing energy waste;

[0043] At the same time, when the pressurized air entering the insulated air storage tank 404 is greater than the pressure relief value set by the pressure relief valve on the pressure relief pipe 406, the pressure relief valve automatically opens to relieve the pressure. At this time, excess steam transported into the insulated air storage tank 404 is discharged from the insulated air storage tank 404 through the pressure relief pipe 406, thereby keeping the internal air pressure of the insulated air storage tank 404 constant, thereby preventing the internal pressure of the insulated air storage tank 404 from being too high and causing safety hazards.

[0044] It should be additionally explained that both the exhaust pipe 403 and the gas supply pipe 405 are provided with a one-way valve.

[0045] Example 3: Reference Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 8 , Fig. 9, a sludge-based biochar production device, which is basically the same as Example 1, and further, a scraper 5 is sleeved on the comb plate 201, a gas delivery cavity 6 is opened in the scraper 5, and a plurality of air injection holes 601 connected to the gas delivery cavity 6 are opened on the scraper 5, a hollow cavity 602 is opened at one end of the electric heating tube 101, and a booster pipe 1 603 connected to the gas delivery cavity 6 is arranged on the scraper 5, and the end of the booster pipe 1 603 away from the gas delivery cavity 6 is connected to the hollow cavity 602, and a booster pipe 2 604 is fixedly connected to the insulated gas storage box 404, and the end of the booster pipe 2 604 away from the insulated gas storage box 404 is connected to the hollow cavity 602 through a rotary joint 605, and the rotary joint 605 is arranged on the electric heating tube 101 and is coaxially arranged with the electric heating tube 101, and a solenoid valve is arranged on the booster pipe 2 604.

[0046] A guide rod 501 is fixedly connected to the scraper 5, and one end of the guide rod 501 passes through the comb plate 201 and is slidably connected to the electric heating tube 101. A limiting block 502 is fixedly connected to the guide rod 501, and a push block 504 is fixedly connected to the support base 1. The push block 504 is used in conjunction with the guide rod 501. A spring 503 is sleeved on the guide rod 501, and one end of the spring 503 is fixedly connected to the limiting block 502, and the other end is fixedly connected to the outer wall of the electric heating tube 101.

[0047] The side of the push block 504 facing the electric heating tube 101 is arranged in an arc shape, and the side of the push block 504 fixedly connected to the support base 1 is arranged in a plane.

[0048] During the continuous rotation of the electric heating tube 101, when the scraper 5 rotates with the comb plate 201 to a position close to the push block 504, the push block 504 will push the guide rod 501, so that the guide rod 501 drives the scraper 5 to slide along the comb plate 201 away from the inner wall of the electric heating tube 101, and compresses the spring 503, so that it can clean up the light garbage such as garbage bags remaining on the comb plate 201, and prevent the light garbage such as garbage bags remaining on the comb plate 201 from being mixed into the sludge for the second time, thereby improving the thoroughness of garbage cleaning. At the same time, the cleaned light garbage such as garbage bags can fall into the filter cartridge 2. When the scraper 5 rotates away from the push block 504, the spring 503 recovers its deformation, pushing the scraper 5 to slide and reset along the comb plate 201 toward the inner wall of the electric heating tube 101;

[0049] At the same time, the scraper 5 that reciprocates on the comb plate 201 can also be used to dredge the tooth grooves of the comb plate 201, so as to keep the tooth grooves unobstructed. Since the unobstructed tooth grooves help to break the uneven flow state of the sludge, the sludge forms a good convection in the electric heating cylinder 101, so that each part of the sludge can fully contact the heating wall, thereby improving the heating efficiency and reducing the water content of the sludge more quickly and evenly.

[0050] At the same time, the electromagnetic valve on the second boosting pipe 604 is intermittently opened, so that the high-temperature gas stored in the heat-insulating gas storage box 404 is transported into the inner gas delivery chamber 6 through the second boosting pipe 604, the rotary joint 605, the hollow cavity 602 and the first boosting pipe 603, and then ejected through the jet hole 601. The ejected high-temperature gas can not only produce an impact force on the garbage on the comb plate 201, so that it can overcome the adhesion between the comb plate 201 and the scraper 5 and detach, thereby realizing efficient cleaning of the comb plate 201, but also can contact the sludge in the electric heating cylinder 101, so that it can dry the sludge again, which helps to further reduce the water content of the sludge and improve the dryness of the sludge.

[0051] By utilizing the collected high-temperature gas to clean the light garbage remaining on the comb plate 201 and to dry the sludge again, energy recycling is achieved and the energy utilization rate of the equipment is improved.

[0052] When the sludge treatment is completed, first turn off the heating device in the electric heating cylinder 101 to gradually reduce the temperature in the electric heating cylinder 101, and at the same time turn off the motor 3 to stop the rotation of the electric heating cylinder 101, then remove the fixed connection between the cover plate 102 and the support base 1, and then open the cover plate 102, take out the filter cartridge 2 from the electric heating cylinder 101, and then clean the garbage in the filter cartridge 2. At the same time, the treated sludge can be taken out of the electric heating cylinder 101 with the help of tools, and then added to the carbonization furnace for subsequent biochar processing.

[0053] It should be noted that both the boost pipe 1 603 and the boost pipe 2 604 are provided with a one-way valve;

[0054] The boost pipe 1 603 is a flexible hose that can be stretched and contracted, so the boost pipe 1 603 will not interfere with the movement of the scraper 5;

[0055] It should be noted that when the air pressure inside the electric heating tube 101 is too high, the pressure can be released by opening the sealing cover on the filling pipe.

[0056] Example 4: Reference Fig. 9 , a sludge-based biochar production device, which is basically the same as Example 1, and further, a sealing groove is opened on the electric heating cylinder 101, a sealing plug 104 is fixedly connected to the cover plate 102, and the sealing plug 104 is inserted into the sealing groove, and a sealing gasket 103 is provided on the electric heating cylinder 101, and the sealing gasket 103 is in contact with the cover plate 102;

[0057] A double seal is formed by the plug-in fit between the sealing plug 104 and the sealing groove and the fit between the sealing gasket 103 and the cover plate 102, which effectively prevents the leakage of gas in the electric heating tube 101 (such as water vapor and pyrolysis gas generated during the heating process), thereby ensuring the sealing performance of the equipment.

[0058] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as above with a preferred embodiment, it is not used to limit the present invention.

Claims

1. A sludge-based biochar production device, comprising a support base (1), characterized in that: Also includes: The electric heating cartridge (101) connected to the support base (1) is rotated, Wherein, one end of the electric heating tube (101) is open; A cover plate (102) is rotatably connected to the electric heating tube (101) and is used to close the opening of the electric heating tube (101). The filter cartridge (2) is arranged in the electric heating cartridge (101) and is fixedly connected to the cover plate (102). The upper end of the filter cartridge (2) is open, a fixing rod (105) is fixedly connected to the cover plate (102), and the fixing rod (105) is detachably connected to the support base (1) via a plurality of fixing bolts; A plurality of comb plates (201) are fixedly connected to the inner wall of the electric heating cylinder (101) at equal intervals around the circumference.

2. A sludge-based biochar production device according to claim 1, characterized in that: One end of the comb plate (201) away from the inner wall of the electric heating cylinder (101) is in contact with the outer wall of the filter cylinder (2).

3. A sludge-based biochar production device according to claim 1, characterized in that: A motor (3) is fixedly mounted on the support base (1), a gear (301) is fixedly connected to the output end of the motor (3), a gear ring (302) is fixedly mounted on the electric heating tube (101), and the gear (301) is meshingly connected to the gear ring (302).

4. The sludge-based biochar production equipment according to claim 1, characterized in that: A filter dehumidification box (4) is fixedly mounted on the support base (1), a gas supply pipe (405) is fixedly connected to the top of the filter dehumidification box (4), an exhaust pipe (403) connected to the electric heating cylinder (101) is arranged on the cover plate (102), and one end of the exhaust pipe (403) away from the cover plate (102) is connected to the filter dehumidification box (4).

5. A sludge-based biochar production device according to claim 4, characterized in that: It also includes a desiccant layer (401) and an activated carbon filter plate (402), wherein the desiccant layer (401) and the activated carbon filter plate (402) are both plugged into the filtering and dehumidifying box (4).

6. A sludge-based biochar production device according to claim 4, characterized in that: A heat-insulating air storage box (404) is fixedly mounted on the filter dehumidification box (4), the filter dehumidification box (4) is connected to the heat-insulating air storage box (404) via an air delivery pipe (405), a pressure relief pipe (406) is fixedly connected to the heat-insulating air storage box (404), and a pressure relief valve is arranged on the pressure relief pipe (406).

7. A sludge-based biochar production device according to claim 6, characterized in that: The comb plate (201) is sleeved with a scraper (5), an air delivery cavity (6) is provided in the scraper (5), a plurality of air injection holes (601) connected to the air delivery cavity (6) are provided on the scraper (5), a hollow cavity (602) is provided at one end of the electric heating tube (101), a booster pipe (603) connected to the air delivery cavity (6) is provided on the scraper (5), and the end of the booster pipe (603) away from the air delivery cavity (6) is connected to the air delivery cavity (6). The hollow cavity (602) is connected, and the heat-insulating air storage box (404) is fixedly connected with a second boosting pipe (604). The end of the second boosting pipe (604) away from the heat-insulating air storage box (404) is connected to the hollow cavity (602) through a rotating joint (605). The rotating joint (605) is arranged on the electric heating tube (101) and is coaxially arranged with the electric heating tube (101). The second boosting pipe (604) is provided with a solenoid valve.

8. The sludge-based biochar production equipment according to claim 7, characterized in that: The scraper (5) is fixedly connected to a guide rod (501), one end of the guide rod (501) passing through the comb plate (201) is slidably connected to the electric heating tube (101), the guide rod (501) is fixedly connected to a limit block (502), the support base (1) is fixedly connected to a push block (504), the push block (504) is used in conjunction with the guide rod (501), the guide rod (501) is sleeved with a spring (503), one end of the spring (503) is fixedly connected to the limit block (502), and the other end is fixedly connected to the outer wall of the electric heating tube (101).

9. The sludge-based biochar production equipment according to claim 8, characterized in that: The side of the push block (504) facing the electric heating tube (101) is arranged in an arc shape, and the side of the push block (504) fixedly connected to the support base (1) is arranged in a plane.

10. The sludge-based biochar production equipment according to claim 1, characterized in that: The electric heating tube (101) is provided with a sealing groove, the cover plate (102) is fixedly connected with a sealing plug (104), the sealing plug (104) is inserted into the sealing groove, and the electric heating tube (101) is provided with a sealing gasket (103), the sealing gasket (103) is in contact with the cover plate (102).

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