Phosphate and ammonia water dosing device for boiler and dosing method

Abstract

The phosphate and ammonia water dosing device comprises a medicine storage tank, a metering pump, a pressure transmitter and a medicine conveying pipe, a third flange opening is formed in the lower end of the right side of the medicine storage tank, a first flange opening is formed in one side of the top of the medicine storage tank, and meanwhile a second flange opening is formed in the other side of the top of the medicine storage tank; a stirring motor is mounted at the top of the medicine storage tank, an output shaft of the stirring motor is in transmission connection with a stirrer, and the stirrer is arranged in the medicine storage tank; according to the chemical storage tank, each chemical storage tank is integrated with a whole set of pipeline conveying system and two metering pumps, the two metering pumps are independently started during working, one metering pump works and the other metering pump is in a standby state, the overall integration degree is high, and the chemical storage tank is provided with a first flange opening, a second flange opening and a third flange opening; a chemical feeder, a barrel inserting pump or conductivity monitoring can be selectively installed according to the use environment, the use mode is more flexible, and the application range is widened.

Description

Technical Field

[0001] This invention relates to the technical field of boiler chemical dosing, and in particular to a phosphate and ammonia dosing device and method for boilers. Background Technology

[0002] Phosphate and ammonia dosing are important operations in boiler water treatment. Adding phosphate to the boiler water reacts with calcium and magnesium ions in the water to form precipitates such as calcium phosphate and magnesium phosphate. These precipitates can be discharged through the boiler's blowdown system, thus preventing the formation of scale on the boiler's heating surfaces, ensuring the boiler's heat transfer efficiency, and reducing energy consumption. Ammonia is added because ammonia is alkaline when dissolved in water. Adding it to the boiler water can raise the pH value, controlling it within the range of 8.5-9.5 to prevent acidic substances from corroding the boiler metal. Therefore, it needs to be used in conjunction with a dosing device during boiler operation.

[0003] Existing boiler dosing equipment has drawbacks because the phosphate solution needs to be prepared in advance, and hot water is required for its preparation. However, the raw material delivery pipeline usually lacks a sealing mechanism at the end. As the usage time increases, hot water steam can easily enter the pipeline, causing the raw material to clump inside, affecting the pipeline's smoothness, and also leading to deviations in delivery and metering, thus affecting the dosing effect. Summary of the Invention

[0004] In view of this, the present invention addresses the deficiencies of the prior art, and its main objective is to provide a phosphate and ammonia dosing device and dosing method for boilers, in order to solve the problem mentioned in the background that the existing phosphate dosing equipment lacks an end protection mechanism, which easily leads to the raw material clumping due to excessive humidity inside the dosing pipeline, thus affecting the dosing effect.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A phosphate and ammonia dosing device and method for boilers includes a storage tank, a metering pump, a pressure transmitter, and a delivery pipe. A third flange is installed at the lower right end of the storage tank, and a first flange is installed on one side of the top of the storage tank, while a second flange is installed on the other side of the top. A stirring motor is installed at the top of the storage tank, and the output shaft of the stirring motor is connected to a stirrer, which is located inside the storage tank. A drain valve is installed at the bottom of the storage tank, and a drain pipe is installed behind the drain valve. A liquid extraction pipe is installed at the front end of the bottom inner side of the medicine storage tank, and the bottom of the liquid extraction pipe is connected to the first one-way valve. The liquid extraction pipe is also installed at the lower front side of the medicine storage tank. Two metering pumps are symmetrically distributed, and the inlet end of each metering pump is connected to a calibration column pipe. Both calibration columns are connected to a first tee, and a second ball valve is installed between each calibration column and the first tee. The first tee is connected to the outlet pipe, and the outlet pipe is connected to the first one-way valve. A Y-type filter is installed in the middle of the outlet pipe.

[0007] Furthermore, each metering pump has a pressure tank connected in series at its outlet end, and a first backflow valve and a second backflow valve are connected in parallel between the outlet end of each metering pump and the pressure tank. Both first backflow valves are connected to a second three-way valve. The second three-way valve is connected to a second check valve, and the second check valve is installed on the upper front side of the medicine storage tank.

[0008] Furthermore, each of the second backflow valves is connected in series with a third ball valve, and the two third ball valves are connected in series with each other, while each third ball valve is connected in parallel with a fourth ball valve.

[0009] Furthermore, the pressure transmitter is connected to one of the fourth ball valves; the drug delivery pipe is connected to the other fourth ball valve.

[0010] Furthermore, a water inlet pipe is installed on the upper rear side of the outer wall of the medicine storage tank, and a double control ball valve is installed on the water inlet pipe; a level gauge is provided on the left side of the water inlet pipe, and a drain valve is installed at the bottom of the level gauge; two first ball valves are symmetrically installed at both ends of the level gauge, and both first ball valves are connected to the medicine storage tank.

[0011] Furthermore, it includes a dosing device; the dosing device is connected to a second flange port flange, and the bottom of the dosing device extends into the interior of the storage tank.

[0012] Furthermore, the dosing device includes a dosing device housing and a sealed piston; a drive motor is installed on the top of the dosing device housing, and the output shaft of the drive motor is connected to the feeding screw, while a lever is installed on one side of the feeding screw;

[0013] Furthermore, the sealing piston is installed at the bottom of the dosing device housing, and four connecting rods are provided on the outer wall of the sealing piston at equal angles about the vertical axis of the sealing piston. The top of each connecting rod is connected to the slide plate. A return spring is installed on the top of the slide plate, and the return spring is wrapped around the lower outer wall of the dosing device housing. The top of the return spring is fixedly connected to the outer wall of the dosing device housing.

[0014] Furthermore, a sleeve is installed at the bottom of the feeding screw, and the sleeve is rotatably connected to the top of the sealing piston, while the bottom of the feeding screw is engaged with the top of the sealing piston.

[0015] Furthermore, the sealing piston is connected to the dosing device housing by a spline connection, and the sealing piston, feeding screw, connecting rod, slide plate and return spring form a telescopic structure;

[0016] Furthermore, the centerline of the dosing device housing, the centerline of the feeding screw, and the centerline of the sealing piston are all on the same vertical straight line.

[0017] Furthermore, it includes a barrel pump and a conductivity monitor; the barrel pump is connected to a first flange; the conductivity monitor is connected to a third flange.

[0018] A method for adding chemicals to a boiler phosphate and ammonia dosing device:

[0019] Step 1: Connect the ammonia supply pipeline of the denitrification system to the water filling pipe on the storage tank for storing ammonia, and open the double control ball valve to inject ammonia into the storage tank through the water filling pipe for storage; at the same time, connect the second flange to the ammonia recovery system to prevent ammonia leakage, and start the conductivity monitor to continuously monitor the ammonia concentration. Connect the outlet of the tank pump to the corresponding delivery pipe.

[0020] Connect the hot water supply pipe to the water inlet pipe on the storage tank for storing phosphate solution, and open the double control ball valve. During preparation, hot water is injected into the storage tank through the water inlet pipe for storage. Connect the phosphate raw material supply pipe to the feed pipe to deliver the required phosphate raw material to the inside of the dosing device for temporary storage in a measured amount.

[0021] Step 2: Before preparing the phosphate solution, start the drive motor to drive the feeding screw and the lever to rotate simultaneously. During the rotation of the feeding screw and the lever, the lever rotates close to the inner edge of the dosing device housing to prevent the raw material from sticking to the inner wall of the dosing device housing. At the same time, the rotating feeding screw pushes the phosphate raw material to continuously convey it to the bottom of the dosing device housing.

[0022] During the rotation of the feeding screw, the sealing piston will intermittently push the sealing piston downward. When the sealing piston slides downward, a gap will appear at the connection between the side of the sealing piston and the dosing device housing. At this time, some phosphate raw material will be discharged through the gap. Then, the sealing piston will be reset under the action of the return spring, and the opening and closing state will be repeated until the raw material stored inside the dosing device housing is completely emptied. Then the drive motor will be turned off. At this time, the sealing piston will reset again to block the bottom of the dosing device housing, preventing water from entering the inside of the dosing device housing and ensuring that the inside of the dosing device housing remains dry.

[0023] Step 3: Simultaneously open the first ball valves at both ends of the level gauge to facilitate observation of the water level inside the storage tank. During the preparation stage, start the stirring motor to drive the stirrer to rotate and mix the ammonia or phosphate solution stored inside the storage tank. At the same time, ensure that all second, third, and fourth ball valves are kept open.

[0024] Step 4: When chemical dosing is required, start a single metering pump to extract the ammonia or phosphate solution stored in the corresponding storage tank through the corresponding extraction pipe, the first one-way valve, the outlet pipe, and then filter it through the Y-type filter. The ammonia or phosphate solution then enters the corresponding calibration column and is continuously delivered to the corresponding pressure tank by the metering pump. When the pressure inside the pressure tank reaches the threshold, the ammonia or phosphate solution in the pipeline will first continue to flow through the second backflow valve, and then through the corresponding third and fourth ball valves before being continuously injected into the boiler through the delivery pipe.

[0025] Step 5: When the set pressure threshold of the first backflow valve is greater than the set pressure threshold of the second backflow valve, if a blockage occurs at the end of the pipeline, causing excessive pressure inside the pressure tank, some ammonia or phosphate solution in the pipeline will be transported to the second three-way valve through the first backflow valve, and then flow back to the corresponding storage tank through the corresponding second check valve to complete the automatic pressure relief.

[0026] Compared with the prior art, the present invention has obvious advantages and beneficial effects. Specifically, as can be seen from the above technical solution:

[0027] 1. In this invention, a medicine storage tank is provided. Each medicine storage tank integrates a complete pipeline delivery system and two metering pumps. The two metering pumps start independently during operation, with one working and the other in standby mode. The overall integration is high. Furthermore, the medicine storage tank is equipped with a first flange, a second flange, and a third flange. Depending on the environment, a dosing device, a tank pump, or conductivity monitoring can be selectively installed, making the usage more flexible and improving the applicability.

[0028] 2. In this invention, a dosing device is provided. The dosing device, together with a feed pipe, is connected to the phosphate conveying system. During preparation, the raw material is injected into the interior of the dosing device shell through the feed pipe for temporary storage. When it is necessary to add phosphate to the storage tank, the drive motor is started to drive the feeding screw to rotate, which pushes the phosphate continuously towards the bottom of the dosing device shell. A sealing piston is provided at the bottom of the dosing device shell, which is kept in close contact with the bottom of the dosing device shell under the action of a return spring, ensuring that the bottom of the dosing device shell is in a closed state. During the rotation of the feeding screw, the pushing of the phosphate will exert a certain downward pressure on the sealing piston. Furthermore, because the connection between the feeding screw and the top of the sealing piston has a single-sided arc structure, it will intermittently push the sealing piston downward and then reset under the rebound of the return spring. During the downward sliding of the sealing piston, a gap will appear at the connection between the sealing piston and the dosing device housing. At this time, the phosphate raw material will continuously be discharged through the gap. Since it is a one-way output, the discharged phosphate will also absorb steam and prevent steam from entering the dosing device housing. At the same time, after the dosing is completed, the sealing piston will quickly reset, keeping the bottom of the dosing device housing closed again, ensuring that the inside of the dosing device housing remains dry.

[0029] 3. In this invention, a pressure tank, a second backflow valve, a second three-way valve, and a second one-way valve are provided. During the dosing stage, ammonia or phosphate solution is continuously delivered to the corresponding pressure tank by a metering pump. After being pressurized to the pressure threshold in the pressure tank, it continues to flow through the second backflow valve. Since the set pressure threshold of the first backflow valve is greater than that of the second backflow valve, when a blockage occurs at the end of the pipeline, causing excessive pressure inside the pressure tank, some of the ammonia or phosphate solution in the pipeline will be delivered to the second three-way valve through the first backflow valve, and then flow back to the corresponding storage tank through the corresponding second one-way valve to complete the automatic pressure relief, thereby improving the safety of use.

[0030] To more clearly illustrate the structural features and effects of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0031] Figure 1 This is a three-dimensional structural schematic diagram of the boiler phosphate dosing device in this invention;

[0032] Figure 2 This is the present invention. Figure 1 Another perspective view;

[0033] Figure 3 This is the present invention. Figure 2 Another perspective view;

[0034] Figure 4 This is the present invention. Figure 3 Another perspective view;

[0035] Figure 5 This is the present invention. Figure 4 Cross-sectional view in the AA direction;

[0036] Figure 6 This is a three-dimensional structural diagram of the dosing device in this invention;

[0037] Figure 7 This is a three-dimensional structural diagram of the feeding screw in this invention;

[0038] Figure 8 This is a three-dimensional structural schematic diagram of the ammonia dosing device for boilers in this invention;

[0039] Figure 9 This is the present invention. Figure 8 Another perspective view;

[0040] Figure 10 This is the present invention. Figure 9 Another perspective view;

[0041] Figure 11 This is the present invention. Figure 10 Cross-sectional view in the middle BB direction.

[0042] The attached figures are labeled as follows:

[0043] 1-Storage tank, 2-Water inlet pipe, 3-Double control ball valve, 4-Level gauge, 5-First ball valve, 6-Drain valve, 7-First flange, 8-Second flange, 9-Third flange, 10-Agitator motor, 11-Agitator, 12-Liquid extraction pipe, 13-First check valve, 14-Discharge pipe, 15-Y-type filter, 16-First tee, 17-Second ball valve, 18-Calibration column, 19-Metering pump, 20-First backflow valve, 21-Second tee, 22-Second check valve, 23-Third ball valve 24-Pressure tank, 25-Fourth ball valve, 26-Pressure transmitter, 27-Dosing pipe, 28-Dosing device, 2801-Dosing device housing, 2802-Drive motor, 2803-Feeding screw, 2804-Pulley, 2805-Feed pipe, 2806-Sealing piston, 2807-Connecting rod, 2808-Slide plate, 2809-Reset spring, 2810-Sleeve rod, 29-Barrel pump, 30-Conductivity monitor, 31-Drain valve, 32-Drain pipe, 33-Second backflow valve. Detailed Implementation

[0044] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0045] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present application.

[0046] Please refer to Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 8 , Figure 9 and Figure 10 As shown, the system includes a medicine storage tank 1, a metering pump 19, a pressure transmitter 26, and a delivery pipe 27. A third flange 9 is installed at the lower right end of the medicine storage tank 1, and a first flange 7 is installed on one side of the top of the medicine storage tank 1. A second flange 8 is installed on the other side of the top of the medicine storage tank 1. A stirring motor 10 is installed at the top of the medicine storage tank 1, and the output shaft of the stirring motor 10 is connected to a stirrer 11, which is located inside the medicine storage tank 1. The bottom of the medicine storage tank 1... A drain valve 31 is installed, and a drain pipe 32 is installed on the rear side of the drain valve 31; a liquid extraction pipe 12 is installed at the front end of the bottom inner side of the medicine storage tank 1, and the bottom of the liquid extraction pipe 12 is connected to the first one-way valve 13. The liquid extraction pipe 12 is also installed at the lower front side of the medicine storage tank 1; two metering pumps 19 are symmetrically distributed, and the inlet end of each metering pump 19 is connected to a calibration column 18 pipe; both calibration columns 18 are connected to a first tee 16, and each... A second ball valve 17 is installed between the calibration column 18 and the first three-way valve 16; the first three-way valve 16 is connected to the outlet pipe 14, and the outlet pipe 14 is connected to the first one-way valve 13, while a Y-type filter 15 is installed in the middle of the outlet pipe 14; a pressure tank 24 is connected in series at the outlet end of each metering pump 19, and a first backflow valve 20 and a second backflow valve 33 are connected in parallel between the outlet end of each metering pump 19 and the pressure tank 24, while the two first backflow valves... All valves 20 are connected to the second three-way valve 21; the second three-way valve 21 is connected to the second one-way valve 22, and the second one-way valve 22 is installed on the upper front side of the medicine storage tank 1; each of the second backflow valves 33 is connected in series with a third ball valve 23, and the two third ball valves 23 are connected in series with each other, while each third ball valve 23 is connected in parallel with a fourth ball valve 25; the pressure transmitter 26 is connected to one of the fourth ball valves 25; the medicine delivery pipe 27 is connected to the other fourth ball valve 25.

[0047] More specifically, when using the two metering pumps 19, one is in the start-up state and the other is in the standby state, and the metering pump 19 is a hydraulic diaphragm metering pump.

[0048] As a further explanation of this embodiment, during use, the internal pressure of the pipeline is continuously and remotely transmitted to the remote DCS system via the pressure transmitter 26.

[0049] Please refer to Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 8 and Figure 9 As shown, in this embodiment, a water inlet pipe 2 is installed on the upper rear side of the outer wall of the medicine storage tank 1, and a double control ball valve 3 is installed on the water inlet pipe 2; a liquid level sensor 4 is provided on the left side of the water inlet pipe 2, and a drain valve 6 is installed at the bottom of the liquid level sensor 4; two first ball valves 5 are symmetrically installed at both ends of the liquid level sensor 4, and both first ball valves 5 are connected to the medicine storage tank 1.

[0050] To be more specific, the level gauge 4 is a stainless steel bicolor level gauge, and all materials inside the equipment are made of stainless steel.

[0051] As a further explanation of this embodiment, the drain valve 6 facilitates the separate emptying of the level gauge 4.

[0052] Please refer to Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown, in this embodiment, a dosing device 28 is included; the dosing device 28 is flange-connected to the second flange port 8, and the bottom of the dosing device 28 extends into the interior of the storage tank 1.

[0053] More specifically, the flange connection method facilitates disassembly and assembly, improving the flexibility of use.

[0054] As a further explanation of this embodiment, phosphate raw materials are added to the interior of the storage tank 1 through the dosing device 28.

[0055] Please refer to Figure 6 and Figure 7As shown, in this embodiment, the dosing device 28 includes a dosing device housing 2801 and a sealing piston 2806. A drive motor 2802 is installed on the top of the dosing device housing 2801, and the output shaft of the drive motor 2802 is connected to the feeding screw 2803. A lever 2804 is installed on one side of the feeding screw 2803. The sealing piston 2806 is installed at the bottom of the dosing device housing 2801, and four connecting rods 2807 are evenly distributed on the outer wall of the sealing piston 2806 about the vertical axis of the sealing piston 2806. The top of each connecting rod 2807 is connected to a sliding plate 2808. A return spring 2809 is installed on the top of the sliding plate 2808, and the return spring 2809 is wrapped around the lower outer wall of the dosing device housing 2801. The top of the return spring 2809 is fixedly connected to the outer wall of the dosing device housing 2801.

[0056] More specifically, the feeding screw 2803 drives the lever 2804 to rotate synchronously while rotating.

[0057] As a further explanation of this embodiment, the edge of the lever 2804 is close to the inner wall edge of the dosing device housing 2801, so as to prevent the raw material from sticking to the inner wall of the dosing device housing 2801 during rotation.

[0058] Please refer to Figure 6 and Figure 7 As shown, in this embodiment, a sleeve 2810 is installed at the bottom of the feeding screw 2803, and the sleeve 2810 is rotatably connected to the top of the sealing piston 2806. At the same time, the bottom of the feeding screw 2803 is engaged with the top of the sealing piston 2806.

[0059] More specifically, the length of the sleeve 2810 is greater than the maximum sliding distance of the sealing piston 2806.

[0060] As a further explanation of this embodiment, the bottom of the feeding screw 2803 and the meshing part of the sealing piston 2806 have a single-sided arc structure. Therefore, the feeding screw 2803 will gradually push the sealing piston 2806 to slide downward during the rotation process.

[0061] Please refer to Figure 6 and Figure 7 As shown, in this embodiment, the sealing piston 2806 is connected to the dosing device housing 2801 by a spline connection, and the sealing piston 2806, the feeding screw 2803, the connecting rod 2807, the sliding plate 2808 and the return spring 2809 form a telescopic structure; the axis of the dosing device housing 2801, the axis of the feeding screw 2803 and the axis of the sealing piston 2806 are all on the same vertical straight line.

[0062] More specifically, the spline connection ensures that the sealing piston 2806 does not rotate synchronously with the feed screw 2803.

[0063] As a further explanation of this embodiment, after the sealing piston 2806 slides to its limit distance, it is quickly reset by the retraction action of the reset spring 2809.

[0064] Please refer to Figure 8 , Figure 9 , Figure 10 and Figure 11 As shown, in this embodiment, a barrel pump 29 and a conductivity monitor 30 are included; the barrel pump 29 is connected to the first flange port 7; and the conductivity monitor 30 is connected to the third flange port 9.

[0065] More specifically, the ammonia concentration inside the medicine storage tank 1 is continuously monitored using a conductivity monitor 30.

[0066] As a further explanation of this embodiment, the drum pump 29 is used to output ammonia water separately in an emergency.

[0067] A method for adding chemicals to a boiler phosphate and ammonia dosing device:

[0068] Step 1: Connect the ammonia supply pipeline of the denitrification system to the water filling pipe 2 on the storage tank 1 for storing ammonia, and open the double control ball valve 3 to inject ammonia into the storage tank 1 for storage through the water filling pipe 2; at the same time, connect the second flange port 8 to the ammonia recovery system to prevent ammonia leakage, and start the conductivity monitor 30 to continuously monitor the ammonia concentration. Connect the outlet of the tank pump 29 to the corresponding delivery pipe 27.

[0069] Connect the hot water supply pipe to the water inlet pipe 2 on the storage tank 1 for storing phosphate solution, and open the double control ball valve 3. During preparation, hot water is injected into the storage tank 1 through the water inlet pipe 2 for storage. Connect the phosphate raw material supply pipe to the feed pipe 2805 to quantitatively deliver the required phosphate raw material to the inside of the dosing device shell 2801 for temporary storage.

[0070] Step 2: Before preparing the phosphate solution, start the drive motor 2802 to drive the feeding screw 2803 and the lever 2804 to rotate simultaneously. During the rotation of the feeding screw 2803 and the lever 2804, the lever 2804 rotates close to the inner edge of the dosing device housing 2801 to prevent the raw material from sticking to the inner wall of the dosing device housing 2801. At the same time, the rotating feeding screw 2803 pushes the phosphate raw material to continuously convey to the bottom of the dosing device housing 2801.

[0071] During rotation, the feeding screw 2803 intermittently pushes the sealing piston 2806 downward. When the sealing piston 2806 slides downward, a gap appears at the connection between the side of the sealing piston 2806 and the dosing device housing 2801. At this time, some phosphate raw material is discharged through the gap. Then, the sealing piston 2806 is reset under the recycling action of the return spring 2809, and the opening and closing state is repeated until the raw material stored inside the dosing device housing 2801 is completely emptied. Then the drive motor 2802 is turned off. At this time, the sealing piston 2806 resets again to block the bottom of the dosing device housing 2801, preventing water from entering the interior of the dosing device housing 2801 and ensuring that the interior of the dosing device housing 2801 remains dry.

[0072] Step 3: Simultaneously open the first ball valves 5 at both ends of the level gauge 4 to facilitate observation of the internal water level of the storage tank 1. During the preparation stage, start the stirring motor 10 to drive the stirrer 11 to rotate and stir and mix the ammonia or phosphate solution stored inside the storage tank 1. At the same time, ensure that all second ball valves 17, third ball valves 23 and fourth ball valves 25 are kept open.

[0073] Step 4: When chemical dosing is required, start a single metering pump 19 to extract the ammonia or phosphate solution stored in the corresponding storage tank 1 through the corresponding extraction pipe 12, the first one-way valve 13, and the outlet pipe 14. After passing through the Y-type filter 15, the ammonia or phosphate solution is filtered. Then, the ammonia or phosphate solution enters the corresponding calibration column 18 and is continuously delivered to the corresponding pressure tank 24 by the metering pump 19. When the internal pressure of the pressure tank 24 reaches the threshold, the ammonia or phosphate solution in the pipeline will first pass through the second backflow valve 33 to continue flowing, and then through the corresponding third ball valve 23 and fourth ball valve 25, and then be continuously injected into the boiler through the delivery pipe 27.

[0074] Step 5: The set pressure threshold of the first backflow valve 20 is greater than the set pressure threshold of the second backflow valve 33. When the end of the pipeline is blocked, causing the pressure inside the pressure tank 24 to be too high, some of the ammonia or phosphate solution in the pipeline will be transported to the second three-way valve 21 through the first backflow valve 20, and then flow back to the corresponding medicine storage tank 1 through the corresponding second one-way valve 22 to complete the automatic pressure relief.

[0075] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the technical scope of the present invention. Therefore, any minor modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A phosphate and ammonia dosing device for boilers, characterized in that: The system includes a medicine storage tank (1), a metering pump (19), a pressure transmitter (26), and a delivery pipe (27). A third flange (9) is installed at the lower right end of the medicine storage tank (1), and a first flange (7) is installed on one side of the top of the medicine storage tank (1). A second flange (8) is installed on the other side of the top of the medicine storage tank (1). A stirring motor (10) is installed on the top of the medicine storage tank (1), and the output shaft of the stirring motor (10) is connected to a stirrer (11). The stirrer (11) is located inside the medicine storage tank (1). A drain valve (31) is installed at the bottom of the medicine storage tank (1), and a drain pipe (32) is installed behind the drain valve (31). A pipe is installed at the front end of the inner bottom of the medicine storage tank (1). The tank is equipped with a liquid extraction pipe (12), the bottom of which is connected to a first one-way valve (13). The liquid extraction pipe (12) is installed on the lower front side of the storage tank (1). Two metering pumps (19) are symmetrically distributed, and the inlet end of each metering pump (19) is connected to a calibration column (18) pipe. Both calibration columns (18) are connected to a first tee (16), and a second ball valve (17) is installed between each calibration column (18) and the first tee (16). The first tee (16) is connected to the outlet pipe (14), and the outlet pipe (14) is connected to the first one-way valve (13). A Y-type filter (15) is installed in the middle of the outlet pipe (14). Each metering pump (19) has a pressure tank (24) connected in series at its outlet end, and a first backflow valve (20) and a second backflow valve (33) are connected in parallel between the outlet end of each metering pump (19) and the pressure tank (24). At the same time, both first backflow valves (20) are connected to a second three-way valve (21). The second three-way valve (21) is connected to a second check valve (22), and the second check valve (22) is installed on the upper front side of the medicine storage tank (1). Each of the second backflow valves (33) is connected in series with a third ball valve (23), and the two third ball valves (23) are connected in series with each other, while each third ball valve (23) is connected in parallel with a fourth ball valve (25). The pressure transmitter (26) is connected to one of the fourth ball valves (25); the delivery tube (27) is connected to the other fourth ball valve (25).

2. The boiler phosphate and ammonia dosing device according to claim 1, characterized in that: A water inlet pipe (2) is installed on the upper rear side of the outer wall of the medicine storage tank (1), and a double control ball valve (3) is installed on the water inlet pipe (2); a liquid level gauge (4) is provided on the left side of the water inlet pipe (2), and a drain valve (6) is installed at the bottom of the liquid level gauge (4); two first ball valves (5) are symmetrically installed at both ends of the liquid level gauge (4), and both first ball valves (5) are connected to the medicine storage tank (1).

3. The boiler phosphate dosing device according to claim 1, characterized in that: Includes a dosing device (28); the dosing device (28) is flange-connected to the second flange port (8), and the bottom of the dosing device (28) extends into the interior of the storage tank (1).

4. The boiler phosphate dosing device according to claim 3, characterized in that: The dosing device (28) includes a dosing device housing (2801) and a sealing piston (2806); a drive motor (2802) is installed on the top of the dosing device housing (2801), and the output shaft of the drive motor (2802) is connected to the feeding screw (2803), while a lever (2804) is installed on one side of the feeding screw (2803). The sealing piston (2806) is installed at the bottom of the dosing device housing (2801), and four connecting rods (2807) are provided on the outer wall of the sealing piston (2806) at equal angles about the vertical axis of the sealing piston (2806). The top of each connecting rod (2807) is connected to the slide plate (2808). A return spring (2809) is installed on the top of the slide plate (2808), and the return spring (2809) is wrapped around the lower outer wall of the dosing device housing (2801). The top of the return spring (2809) is fixedly connected to the outer wall of the dosing device housing (2801).

5. The boiler phosphate dosing device according to claim 4, characterized in that: The bottom of the feeding screw (2803) is equipped with a sleeve (2810), and the sleeve (2810) is rotatably connected to the top of the sealing piston (2806). At the same time, the bottom of the feeding screw (2803) is engaged with the top of the sealing piston (2806).

6. The boiler phosphate dosing device according to claim 5, characterized in that: The sealing piston (2806) is connected to the dosing device housing (2801) by a spline connection, and the sealing piston (2806), the feeding screw (2803), the connecting rod (2807), the slide plate (2808), and the return spring (2809) form a telescopic structure; The axis of the dosing device housing (2801), the axis of the feeding screw (2803), and the axis of the sealing piston (2806) are all on the same vertical straight line.

7. The ammonia dosing device for boilers according to claim 1, characterized in that: It includes a barrel pump (29) and a conductivity monitor (30); the barrel pump (29) is connected to the first flange port (7); the conductivity monitor (30) is connected to the third flange port (9).

8. A dosing method for a boiler phosphate and ammonia dosing device as described in any one of claims 1-7, characterized in that: Step 1: Connect the ammonia supply pipeline of the denitrification system to the water supply pipe (2) on the storage tank (1) for storing ammonia, and open the double control ball valve (3) to inject ammonia into the storage tank (1) for storage through the water supply pipe (2); at the same time, connect the second flange port (8) to the ammonia recovery system to prevent ammonia leakage, and start the conductivity monitor (30) to continuously monitor the ammonia concentration. Connect the outlet of the barrel pump (29) to the corresponding delivery pipe (27). Connect the hot water supply pipe to the water inlet pipe (2) on the storage tank (1) for storing phosphate solution, and open the double control ball valve (3) to inject hot water into the storage tank (1) through the water inlet pipe (2) for storage during preparation; and connect the phosphate raw material supply pipe to the feed pipe (2805) to quantitatively transport the required phosphate raw material to the inside of the dosing device shell (2801) for temporary storage; Step 2: Before preparing the phosphate solution, start the drive motor (2802) to drive the feeding screw (2803) and the lever (2804) to rotate simultaneously. During the rotation of the feeding screw (2803) and the lever (2804), the lever (2804) rotates close to the inner edge of the dosing device housing (2801) to prevent the raw material from sticking to the inner wall of the dosing device housing (2801). At the same time, the rotating feeding screw (2803) pushes the phosphate raw material to continuously convey to the bottom of the dosing device housing (2801). During the rotation of the feeding screw (2803), it will intermittently push the sealing piston (2806) to slide downward. When the sealing piston (2806) slides downward, a gap will appear at the connection between the side of the sealing piston (2806) and the dosing device housing (2801). At this time, some phosphate raw material will be discharged through the gap. Then, the sealing piston (2806) will be reset under the recycling action of the return spring (2809), and the opening and closing state will be repeated until the raw material stored inside the dosing device housing (2801) is completely emptied. Then the drive motor (2802) will be turned off. At this time, the sealing piston (2806) will be reset again to block the bottom of the dosing device housing (2801) to prevent water from entering the inside of the dosing device housing (2801) and ensure that the inside of the dosing device housing (2801) remains dry. Step 3: Simultaneously open the first ball valves (5) at both ends of the level gauge (4) to facilitate observation of the internal water level of the storage tank (1). During the preparation stage, start the stirring motor (10) to drive the stirrer (11) to rotate and stir the ammonia or phosphate solution stored in the storage tank (1). At the same time, ensure that all second ball valves (17), third ball valves (23) and fourth ball valves (25) are kept open. Step 4: When dosing is required, start a single metering pump (19) to extract the ammonia or phosphate solution stored in the corresponding storage tank (1) through the corresponding extraction pipe (12), the first check valve (13), the outlet pipe (14), and then filter the ammonia or phosphate solution through the Y-type filter (15). The ammonia or phosphate solution then enters the corresponding calibration column (18) and is continuously delivered to the corresponding pressure tank (24) through the metering pump (19). When the pressure inside the pressure tank (24) reaches the threshold, the ammonia or phosphate solution in the pipeline will first pass through the second backflow valve (33) to continue flowing, and then through the corresponding third ball valve (23) and fourth ball valve (25), and then be continuously injected into the boiler through the delivery pipe (27). Step 5: The set pressure threshold of the first backflow valve (20) is greater than the set pressure threshold of the second backflow valve (33). When the end of the pipeline is blocked, causing the pressure tank (24) to be too high, some of the ammonia or phosphate solution in the pipeline will be transported to the second three-way valve (21) through the first backflow valve (20), and then flow back to the corresponding medicine storage tank (1) through the corresponding second check valve (22) to complete the automatic pressure relief.

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