Quantitative liquid adding device for trace nitric acid

Abstract

The invention relates to the technical field of glass processing, and provides a trace nitric acid quantitative liquid adding device which comprises a base, one end of the top of the base is fixedly connected with a nitric acid storage tank, the other end of the top of the base is fixedly connected with a surface strong acid tank, and the outlet end of the nitric acid storage tank and the inlet end of the surface strong acid tank are both fixedly connected with first liquid guide pipes. A three-way pipe is fixedly connected between the two first liquid guide pipes, a liquid adding mechanism is arranged at a middle pipe opening of the three-way pipe and comprises a metering cylinder fixedly connected to the top of the base, a second liquid guide pipe is fixedly connected to one end of the metering cylinder, a piston is slidably connected to the inner side of the metering cylinder, and a driving assembly is arranged on one side of the piston; a first valve and a second valve are arranged on the two first liquid guide pipes respectively, and pushing and pressing pieces are arranged on the two sides of the metering cylinder. The whole process does not need manual operation, and the accuracy of stock solution proportioning is improved.

Description

Technical Field

[0001] The invention relates to the technical field of glass processing, and in particular to a device for quantitatively adding trace nitric acid. Background Art

[0002] At present, with the high demand for glass products, glass is applied to different fields. The processing of glass back covers usually includes etching and thinning processes. In the glass etching and thinning process, etching liquid needs to be configured for erosion and thinning, which requires corresponding preparation devices for preparation.

[0003] After searching, the Chinese patent publication number CN215823047U disclosed "a system for preparing etching liquid online, the system comprising: an etching liquid preparation device, an ultrasonic preheating device and a storage and supply device connected in sequence; wherein, the etching liquid preparation device is provided with a reaction kettle and a magnetic stirrer, and the reaction kettle is provided with at least one preparation reagent inlet, a stirring magnet and a first outlet, which are used to mix the preparation reagents evenly to obtain etching liquid."

[0004] This type of patent mainly introduces different raw materials of etching solution into a container for stirring and mixing. However, it cannot be guaranteed that the raw materials are prepared successfully at one time during the preparation process, and a small amount of stock solution needs to be added subsequently to supplement to meet the best ratio. At present, the liquid is mainly added by manually sucking a small amount of stock solution. This method is easily affected by manual operation and causes inaccurate amount of stock solution added, thereby causing a large error in the final ratio. In view of this, the present invention proposes a device for quantitatively adding trace nitric acid. Summary of the invention

[0005] The invention provides a device for quantitatively adding liquid of trace nitric acid, which solves the problem that manual liquid addition easily causes large ratio errors.

[0006] The technical scheme of the present invention is as follows: a device for quantitatively adding liquid to a trace amount of nitric acid, comprising a base, one end of the top of the base being fixedly connected to a nitric acid storage tank, the other end of the top of the base being fixedly connected to a surface strong acid tank, the outlet end of the nitric acid storage tank and the inlet end of the surface strong acid tank being fixedly connected to a first liquid guide tube, a three-way pipe being fixedly connected between the two first liquid guide tubes, a liquid adding mechanism being arranged at the middle pipe opening of the three-way pipe, the liquid adding mechanism comprising a metering cylinder fixedly connected to the top of the base, one end of the metering cylinder being fixedly connected to a second liquid guide tube, one end of the second liquid guide tube being connected to the middle pipe opening of the three-way pipe, a piston being slidably connected to the inner side of the metering cylinder, a driving assembly for driving the piston to reciprocate and slide being arranged at one side of the piston, a first valve member and a second valve member being arranged on the two first liquid guide tubes respectively, and a pushing member for driving the first valve member and the second valve member to be alternately opened and closed by cooperating with the start of the driving assembly being arranged on both sides of the metering cylinder.

[0007] Preferably, the structures of the first valve component and the second valve component are completely the same; when the first valve component is opened, the second valve component is in a closed state; and when the first valve component is closed, the second valve component is in an open state.

[0008] Preferably, the first valve component includes a valve body, both ends of the valve body are provided with ports, the two ports are respectively connected to the first liquid guide tube and the three-way pipe, the interior of the valve body is fixedly connected to a valve seat, the valve seat is provided with a through groove connecting the two ports, the outer side of the valve body is fixedly connected to a valve cover, the middle part of the valve cover is slidably connected to a valve stem passing through the valve cover, and one end of the valve stem is fixedly connected to a valve core slidably matched with the through groove.

[0009] Preferably, the first valve member further comprises a slider, the slider is slidably connected to the inner side of the valve cover, a return spring is sleeved on the valve stem, one end of the return spring abuts against the slider, and the other end of the return spring abuts against the inner wall of the valve cover.

[0010] Preferably, the pushing member includes a fixed seat, which is fixedly connected to the top of the base, and the top of the fixed seat is slidably connected to a movable rod that penetrates the fixed seat, one end of the movable rod is fixedly connected to the valve stem, and the outer side of the movable rod is fixedly connected to a limiting strip, the limiting strip is slidably connected to the fixed seat, the other end of the movable rod is fixedly connected to a connecting rod, the end of the connecting rod away from the movable rod is fixedly connected to a fixing plate, and one end of the fixing plate is fixedly connected to an arc-surface protrusion.

[0011] Preferably, the driving assembly includes a reciprocating screw, which passes through the side wall of the metering cylinder and extends to the outside of the metering cylinder, the reciprocating screw is slidably connected to the side wall of the metering cylinder, one end of the reciprocating screw is fixedly connected to the piston, the outside of the metering cylinder is rotatably connected to an internal threaded sleeve, the internal threaded sleeve is threadedly connected to the reciprocating screw, the top of the base is provided with a driving member for driving the internal threaded sleeve to rotate, the other end of the reciprocating screw is provided with a guide member for guiding the reciprocating screw to perform reciprocating motion, and the outside of the internal threaded sleeve is provided with a pressing member that intermittently interferes with the arc-surface protrusion to drive the fixed plate to reciprocate in the horizontal direction.

[0012] Preferably, the driving member comprises a motor, the motor is fixedly mounted on the top of the base, the output shaft of the motor is fixedly connected to a gear, and one end of the internal threaded sleeve is fixedly connected to a gear ring meshing with the gear.

[0013] Preferably, the guide member includes a connecting plate, which is fixedly connected to the end of the reciprocating screw rod, one end of the top of the metering cylinder is fixedly connected to the guide plate, the top of the guide plate is slidably connected to a guide rod that passes through the guide plate, one end of the guide rod is fixedly connected to the connecting plate, and the other end of the guide rod is fixedly connected to a stop block.

[0014] Preferably, the pressing member includes a rotating plate fixedly connected to the outside of the internal threaded sleeve, one end of the rotating plate is fixedly connected to a mounting seat, one side of the mounting seat is fixedly connected to a curved top plate, and the curved top plate intermittently interferes with the curved protrusion by cooperating with the rotation of the rotating plate.

[0015] Preferably, when the arc surface top plate abuts against one of the arc surface protrusions, the reciprocating screw rod moves in the forward direction, and when the arc surface top plate abuts against the other arc surface protrusion, the reciprocating screw rod moves in the reverse direction.

[0016] The working principle and beneficial effects of the present invention are as follows: the piston is driven to reciprocate by a driving component. When the piston is away from the second liquid guide tube, the pressure inside the metering cylinder is reduced, and the push member drives the first valve member to open and the second valve member to close, so that the nitric acid solution inside the nitric acid storage tank is introduced into the three-way pipe, and then introduced into the metering cylinder through the three-way pipe; when the piston is close to the second liquid guide tube, the pressure inside the metering cylinder is increased, and the push member drives the first valve member to close and the second valve member to open, so that the nitric acid solution inside the metering cylinder is introduced into the three-way pipe through the second liquid guide tube, and then introduced into the surface strong acid tank through the three-way pipe. Since the displacement of the reciprocating movement of the piston is certain, the amount of nitric acid introduced and discharged by the metering cylinder each time is quantitative, so that intermittent addition of quantitative nitric acid into the surface strong acid tank can be achieved. The whole process does not require manual operation, which improves the accuracy of the stock solution ratio. Moreover, the whole structure adopts a mechanical structure to achieve quantitative addition of nitric acid solution, and does not need to be implemented by an electronic control system, which avoids the problem of poor stability of electronic components in the electronic control system causing failure of the addition work or inaccurate addition amount. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0018] Figure 1 It is a structural schematic diagram of a device for quantitatively adding liquid of trace nitric acid of the present invention;

[0019] Figure 2 It is a structural schematic diagram of the liquid adding mechanism of the present invention;

[0020] Figure 3 is a schematic structural diagram of a first valve member of the present invention;

[0021] Figure 4 It is a schematic structural diagram of the push member of the present invention;

[0022] Figure 5 It is a structural schematic diagram of the driving assembly of the present invention;

[0023] Figure 6 It is a structural schematic diagram of the driving member of the present invention;

[0024] Figure 7 It is a structural schematic diagram of the guide member of the present invention;

[0025] Figure 8 It is a schematic structural diagram of the top pressure piece of the present invention.

[0026] In the figure: 1, base; 2, nitric acid storage tank; 3, surface strong acid tank; 4, first liquid guide tube; 5, three-way pipe; 6, liquid adding mechanism; 61, metering cylinder; 62, second liquid guide tube; 63, piston; 64, driving assembly; 641, reciprocating screw rod; 642, internal thread sleeve; 643, driving member; 6431, motor; 6432, gear; 6433, gear ring; 644, guide member; 6441, connecting plate; 6442, guide plate; 6443, guide rod; 6444, stop Block; 645, top pressure piece; 6451, rotating plate; 6452, mounting seat; 6453, arc top plate; 65, pushing piece; 651, fixed seat; 652, movable rod; 653, limit strip; 654, connecting rod; 655, fixed plate; 656, arc convex block; 7, first valve member; 71, valve body; 72, valve seat; 73, through groove; 74, valve cover; 75, valve stem; 76, valve core; 77, slider; 78, return spring; 79, port; 8, second valve member. DETAILED DESCRIPTION

[0027] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] like Figures 1 to 8As shown, this embodiment proposes a trace nitric acid quantitative liquid adding device, including a base 1, one end of the top of the base 1 is fixedly connected to a nitric acid storage tank 2, the other end of the top of the base 1 is fixedly connected to a surface strong acid tank 3, the outlet end of the nitric acid storage tank 2 and the inlet end of the surface strong acid tank 3 are fixedly connected to a first liquid guide tube 4, a three-way pipe 5 is fixedly connected between the two first liquid guide tubes 4, and a liquid adding mechanism 6 is provided at the middle pipe mouth of the three-way pipe 5, and the liquid adding mechanism 6 includes a metering cylinder 61 fixedly connected to the top of the base 1, one end of the metering cylinder 61 is fixedly connected to a second liquid guide tube 62, and one end of the second liquid guide tube 62 is fixedly connected to the three-way pipe 5. The middle pipe opening of the through pipe 5 is connected, and a piston 63 is slidably connected to the inner side of the metering cylinder 61. A driving assembly 64 for driving the piston 63 to slide back and forth is provided on one side of the piston 63. The first valve member 7 and the second valve member 8 are respectively provided on the two first liquid guide tubes 4. Pushing members 65 are provided on both sides of the metering cylinder 61 for driving the first valve member 7 and the second valve member 8 to open and close alternately by cooperating with the start of the driving assembly 64. The structures of the first valve member 7 and the second valve member 8 are exactly the same. When the first valve member 7 is opened, the second valve member 8 is in a closed state. When the first valve member 7 is closed, the second valve member 8 is in an open state.

[0029] The piston 63 is driven to reciprocate by the driving assembly 64. When the piston 63 is away from the second liquid conduit 62, the pressure inside the metering cylinder 61 decreases, and at the same time, the push member 65 drives the first valve member 7 to open and the second valve member 8 to close, so that the nitric acid solution inside the nitric acid storage tank 2 is introduced into the three-way pipe 5, and then introduced into the metering cylinder 61 through the three-way pipe 5; when the piston 63 is close to the second liquid conduit 62, the pressure inside the metering cylinder 61 increases, and at the same time, the push member 65 drives the first valve member 7 to close and the second valve member 8 to open, so that the nitric acid solution inside the metering cylinder 61 is passed through the three-way pipe 5. The nitric acid is introduced into the surface strong acid tank 3 through the second liquid guide tube 62, and then introduced into the surface strong acid tank 3 through the three-way tube 5. Since the displacement of the reciprocating movement of the piston 63 is certain, the amount of nitric acid introduced and discharged by the metering cylinder 61 each time is quantitative, which can realize the intermittent addition of quantitative nitric acid into the surface strong acid tank 3. The whole process does not require manual operation, which improves the accuracy of the stock solution ratio. Moreover, the whole structure adopts a mechanical structure to realize the quantitative addition of nitric acid liquid, and does not adopt an electronic control system to achieve it, so as to avoid the problem of poor stability of electronic components in the electronic control system causing failure of the liquid addition work or inaccurate liquid addition amount.

[0030] Furthermore, the first valve member 7 includes a valve body 71, both ends of the valve body 71 are provided with ports 79, the two ports 79 are respectively connected to the first liquid guide tube 4 and the three-way tube 5, a valve seat 72 is fixedly connected to the inside of the valve body 71, a through groove 73 connecting the two ports 79 is provided on the valve seat 72, a valve cover 74 is fixedly connected to the outside of the valve body 71, a valve stem 75 penetrating the valve cover 74 is slidably connected to the middle of the valve cover 74, one end of the valve stem 75 is fixedly connected to a valve core 76 slidably matched with the through groove 73, a slider 77 is slidably connected to the inner side of the valve cover 74, a return spring 78 is sleeved on the valve stem 75, one end of the return spring 78 is in contact with the slider 77, and the other end of the return spring 78 is in contact with the inner wall of the valve cover 74, and the valve core 76 of the return spring 78 is slidably matched with the through groove 73 in the initial state. By driving the valve stem 75 to apply a pulling force to the valve core 76, the valve core 76 is separated from the through groove 73, thereby opening the pipeline of the first liquid conduit 4 where the valve body 71 is located; when the valve core 76 and the through groove 73 are slidably engaged, the pipeline of the first liquid conduit 4 where the valve body 71 is located is closed.

[0031] The push member 65 includes a fixed seat 651, which is fixedly connected to the top of the base 1. The top of the fixed seat 651 is slidably connected to a movable rod 652 that penetrates the fixed seat 651. One end of the movable rod 652 is fixedly connected to the valve stem 75. The outer side of the movable rod 652 is fixedly connected to a limit strip 653. The limit strip 653 is slidably connected to the fixed seat 651. The other end of the movable rod 652 is fixedly connected to a connecting rod 654. The end of the connecting rod 654 away from the movable rod 652 is fixedly connected to a fixed plate 655. One end of the fixed plate 655 is fixedly connected to an arc-surface protrusion 656. The driving assembly 64 includes a reciprocating screw rod 641. The reciprocating screw rod 641 penetrates the metering cylinder 61. The side wall of the metering cylinder 61 is extended to the outside of the metering cylinder 61, the reciprocating screw rod 641 is slidably connected to the side wall of the metering cylinder 61, one end of the reciprocating screw rod 641 is fixedly connected to the piston 63, the outer side of the metering cylinder 61 is rotatably connected with an internal threaded sleeve 642, the internal threaded sleeve 642 is threadedly connected to the reciprocating screw rod 641, the top of the base 1 is provided with a driving member 643 for driving the internal threaded sleeve 642 to rotate, the other end of the reciprocating screw rod 641 is provided with a guide member 644 for guiding the reciprocating screw rod 641 to reciprocate, and the outer side of the internal threaded sleeve 642 is provided with a top pressure member 645 which intermittently contacts the arc surface protrusion 656 to drive the fixed plate 655 to reciprocate in the horizontal direction.

[0032] The internal threaded sleeve 642 is driven to rotate by the driving member 643, which causes the reciprocating screw 641 and the internal threaded sleeve 642 to rotate relative to each other, and the reciprocating screw 641 to reciprocate, so that the piston 63 slides back and forth on the inner side of the metering cylinder 61. At the same time, the pressing member 645 intermittently contacts the arc-surface protrusion 656 to drive the fixing plate 655 to reciprocate in the horizontal direction, so that the two connecting rods 654 respectively drive the two valve stems 75 to reciprocate alternately, so that the valve core 76 and the through groove 73 are periodically slidably matched and disengaged, so that the first valve member 7 and the second valve member 8 are alternately opened and closed.

[0033] Furthermore, the driving member 643 includes a motor 6431, which is fixedly mounted on the top of the base 1, and the output shaft of the motor 6431 is fixedly connected to a gear 6432, and one end of the internal thread sleeve 642 is fixedly connected to a gear ring 6433 meshing with the gear 6432. By starting the motor 6431 to drive the gear 6432 to rotate, the gear ring 6433 rotates synchronously, and the internal thread sleeve 642 rotates, so that the reciprocating screw 641 and the internal thread sleeve 642 rotate relative to each other, so that the reciprocating screw 641 reciprocates, and the piston 63 slides back and forth on the inner side of the metering cylinder 61.

[0034] Further, the guide member 644 includes a connecting plate 6441, which is fixedly connected to the end of the reciprocating screw rod 641, one end of the top of the metering cylinder 61 is fixedly connected to a guide plate 6442, the top of the guide plate 6442 is slidably connected to a guide rod 6443 that penetrates the guide plate 6442, one end of the guide rod 6443 is fixedly connected to the connecting plate 6441, and the other end of the guide rod 6443 is fixedly connected to a stopper 6444. The guide rod 6443 can limit the rotation of the connecting plate 6441, and also limit the rotation of the reciprocating screw rod 641, so that the internal thread sleeve 642 and the reciprocating screw rod 641 can rotate relative to each other, and also make the reciprocating screw rod 641 reciprocate.

[0035] Furthermore, the pressing member 645 includes a rotating plate 6451 fixedly connected to the outside of the internal threaded sleeve 642, one end of the rotating plate 6451 is fixedly connected to a mounting seat 6452, one side of the mounting seat 6452 is fixedly connected to a curved top plate 6453, the curved top plate 6453 intermittently conflicts with the curved protrusion 656 by cooperating with the rotation of the rotating plate 6451, when the curved top plate 6453 conflicts with one of the curved protrusions 656, the reciprocating screw rod 641 performs forward movement, and when the curved top plate 6453 conflicts with the other curved protrusion 656, the reciprocating screw rod 641 performs reverse movement.

[0036] Working principle: by starting the motor 6431, the gear 6432 is driven to rotate, so that the gear ring 6433 rotates synchronously, and the internal thread sleeve 642 is rotated, and the guide rod 6443 can limit the rotation of the connecting plate 6441, and the rotation of the reciprocating screw rod 641 can be limited, so that the internal thread sleeve 642 and the reciprocating screw rod 641 can rotate relative to each other, and the reciprocating screw rod 641 can reciprocate, so that the piston 63 slides back and forth on the inner side of the metering cylinder 61, and at the same time, the internal thread sleeve 642 drives the rotating plate 6451 to rotate, so that the mounting seat 6452 drives the arc top plate 6453 to rotate circumferentially;

[0037] When the piston 63 moves away from the second liquid guiding tube 62, the pressure inside the metering cylinder 61 decreases, and the arc top plate 6453 contacts the arc convex block 656 corresponding to the first valve member 7, which causes the fixed plate 655 to slide under the thrust, and the connecting rod 654 drives the movable rod 652 to slide, which also causes the corresponding valve stem 75 to slide under the tension, so that the corresponding valve core 76 is separated from the through groove 73, thereby opening the pipeline of the first liquid guiding tube 4 where the first valve member 7 is located, and closing the pipeline of the first liquid guiding tube 4 where the second valve member 8 is located, so that the nitric acid solution inside the nitric acid storage tank 2 is introduced into the three-way pipe 5, and then introduced into the metering cylinder 61 through the three-way pipe 5;

[0038] When the piston 63 approaches the second liquid guide tube 62, the pressure inside the metering cylinder 61 increases, and the arc top plate 6453 contacts the arc convex block 656 corresponding to the second valve member 8, which causes the fixed plate 655 to slide under the thrust, so that the connecting rod 654 drives the movable rod 652 to slide, and the corresponding valve stem 75 to slide under the tension, so that the corresponding valve core 76 is separated from the through groove 73, thereby opening the first liquid guide tube 4 where the second valve member 8 is located, and the first liquid guide tube 4 where the first valve member 7 is located is closed. The circuit is in a closed state, so that the nitric acid solution inside the metering cylinder 61 is introduced into the three-way pipe 5 through the second liquid guiding tube 62, and then introduced into the surface strong acid tank 3 through the three-way pipe 5. Since the displacement of the reciprocating movement of the piston 63 is certain, the amount of nitric acid introduced and discharged by the metering cylinder 61 each time is quantitative, which can realize the intermittent addition of a certain amount of nitric acid into the surface strong acid tank 3. The whole process does not need to be coordinated by the electronic control system, avoiding the problem of poor stability of electronic components in the electronic control system causing malfunction of the liquid addition work or inaccurate liquid addition amount.

[0039] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A micro nitric acid quantitative liquid adding device, comprising a base (1), one end of the top of the base (1) is fixedly connected to a nitric acid storage tank (2), the other end of the top of the base (1) is fixedly connected to a surface strong acid tank (3), the outlet end of the nitric acid storage tank (2) and the inlet end of the surface strong acid tank (3) are both fixedly connected to a first liquid guide tube (4), characterized in that: A three-way pipe (5) is fixedly connected between the two first liquid guiding tubes (4), and a liquid adding mechanism (6) is arranged at the middle pipe opening of the three-way pipe (5). The liquid adding mechanism (6) comprises a metering cylinder (61) fixedly connected to the top of the base (1), one end of the metering cylinder (61) is fixedly connected to the second liquid guiding tube (62), one end of the second liquid guiding tube (62) is connected to the middle pipe opening of the three-way pipe (5), a piston (63) is slidably connected to the inner side of the metering cylinder (61), and a driving assembly (64) for driving the piston (63) to slide back and forth is arranged on one side of the piston (63), a first valve member (7) and a second valve member (8) are arranged on the two first liquid guiding tubes (4), respectively, and a pushing member (65) is arranged on both sides of the metering cylinder (61) for driving the first valve member (7) and the second valve member (8) to open and close alternately by cooperating with the start of the driving assembly (64).

2. A trace nitric acid quantitative liquid adding device according to claim 1, characterized in that, The structures of the first valve component (7) and the second valve component (8) are completely the same; when the first valve component (7) is opened, the second valve component (8) is in a closed state; and when the first valve component (7) is closed, the second valve component (8) is in an open state.

3. A trace nitric acid quantitative liquid adding device according to claim 1, characterized in that, The first valve member (7) comprises a valve body (71), both ends of the valve body (71) are provided with ports (79), the two ports (79) are respectively connected to the first liquid guide tube (4) and the three-way tube (5), the interior of the valve body (71) is fixedly connected to a valve seat (72), the valve seat (72) is provided with a through groove (73) connecting the two ports (79), the outer side of the valve body (71) is fixedly connected to a valve cover (74), the middle part of the valve cover (74) is slidably connected to a valve stem (75) penetrating the valve cover (74), and one end of the valve stem (75) is fixedly connected to a valve core (76) slidably matched with the through groove (73).

4. A trace nitric acid quantitative liquid adding device according to claim 3, characterized in that, The first valve member (7) further comprises a slider (77), wherein the slider (77) is slidably connected to the inner side of the valve cover (74), and a return spring (78) is sleeved on the valve stem (75), wherein one end of the return spring (78) contacts the slider (77), and the other end of the return spring (78) contacts the inner wall of the valve cover (74).

5. A trace nitric acid quantitative liquid adding device according to claim 4, characterized in that, The pushing member (65) includes a fixed seat (651), the fixed seat (651) is fixedly connected to the top of the base (1), the top of the fixed seat (651) is slidably connected to a movable rod (652) that penetrates the fixed seat (651), one end of the movable rod (652) is fixedly connected to the valve stem (75), the outer side of the movable rod (652) is fixedly connected to a limit strip (653), the limit strip (653) is slidably connected to the fixed seat (651), the other end of the movable rod (652) is fixedly connected to a connecting rod (654), the end of the connecting rod (654) away from the movable rod (652) is fixedly connected to a fixing plate (655), and one end of the fixing plate (655) is fixedly connected to an arc-surface protrusion (656).

6. A trace nitric acid quantitative liquid adding device according to claim 5, characterized in that, The driving assembly (64) comprises a reciprocating screw rod (641), the reciprocating screw rod (641) penetrates the side wall of the metering cylinder (61) and extends to the outside of the metering cylinder (61), the reciprocating screw rod (641) is slidably connected to the side wall of the metering cylinder (61), one end of the reciprocating screw rod (641) is fixedly connected to the piston (63), and the outer side of the metering cylinder (61) is rotatably connected to an internal thread sleeve (642), and the internal thread sleeve (642) is rotatably connected to the reciprocating screw rod ( The base (1) is threadedly connected to the inner thread sleeve (641), the top of the base (1) is provided with a driving member (643) for driving the inner thread sleeve (642) to rotate, the other end of the reciprocating screw rod (641) is provided with a guide member (644) for guiding the reciprocating screw rod (641) to reciprocate, and the outer side of the inner thread sleeve (642) is provided with a pressing member (645) for driving the fixing plate (655) to reciprocate in the horizontal direction by intermittently contacting with the arc surface protrusion (656).

7. A trace nitric acid quantitative liquid adding device according to claim 6, characterized in that, The driving member (643) comprises a motor (6431), wherein the motor (6431) is fixedly mounted on the top of the base (1), an output shaft of the motor (6431) is fixedly connected to a gear (6432), and one end of the internal threaded sleeve (642) is fixedly connected to a gear ring (6433) meshing with the gear (6432).

8. A trace nitric acid quantitative liquid adding device according to claim 6, characterized in that, The guide member (644) comprises a connecting plate (6441), wherein the connecting plate (6441) is fixedly connected to the end of the reciprocating screw rod (641), one end of the top of the metering cylinder (61) is fixedly connected to the guide plate (6442), the top end of the guide plate (6442) is slidably connected to a guide rod (6443) penetrating the guide plate (6442), one end of the guide rod (6443) is fixedly connected to the connecting plate (6441), and the other end of the guide rod (6443) is fixedly connected to a stopper (6444).

9. A trace nitric acid quantitative liquid adding device according to claim 6, characterized in that, The pressing member (645) comprises a rotating plate (6451) fixedly connected to the outside of the internal threaded sleeve (642); one end of the rotating plate (6451) is fixedly connected to a mounting seat (6452); one side of the mounting seat (6452) is fixedly connected to a curved top plate (6453); the curved top plate (6453) intermittently contacts the curved protrusion (656) by cooperating with the rotation of the rotating plate (6451).

10. A trace nitric acid quantitative liquid adding device according to claim 9, characterized in that: When the arc surface top plate (6453) contacts one of the arc surface protrusions (656), the reciprocating screw rod (641) moves in the forward direction; when the arc surface top plate (6453) contacts the other arc surface protrusion (656), the reciprocating screw rod (641) moves in the reverse direction.

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