Control system for cationic starch pulping of paper machine

Abstract

The utility model discloses a control system for cationic starch pulping of a paper machine, which comprises a cationic starch tank, a feeding pump and a digester, a pipeline between the feeding pump and the digester is provided with a material valve for controlling the on-off of the pipeline and controlling whether the feeding pump supplies cationic starch pulp to be processed to the digester or not; the pipeline between the feeding pump and the seasoning valve is in bypass connection with a slurry circulating return pipe which is used for closing the seasoning valve to stop feeding to the digester and circularly pumping slurry pumped out of the feeding pump from the top end of the cationic starch tank to prevent bad materials caused by starch deposition in the pipeline and the tank body and blockage of the pump; and a return valve for controlling the on-off of the pipeline and closing the slurry circulating return pipe in a feeding manner to stop the return circulation of the digester is mounted on the slurry circulating return pipe.

Description

[Technical field]

[0001] The utility model relates to a paper machine cationic starch processing technology, in particular to a control system used for paper machine cationic starch pulping. [Background technology]

[0002] During the paper processing, cationic starch forms a lubricating film on the fiber surface, which reduces the friction between fibers, prevents the cutting and breaking of fiber bundles, and makes the fibers more tightly bonded, thereby improving the paper's compressive resistance. Cationic starch can also enhance the bonding of fiber bundles and improve the surface smoothness of paper. During the calendering process of paper, cationic starch combines with fiber bundles to form a film, which improves the adhesion between fiber bundles, making the paper smoother and smoother.

[0003] Therefore, cationic starch is a very important papermaking additive, which can improve the physical strength, surface smoothness, compressive strength and friction resistance of paper, thereby improving the quality and performance of paper. In the papermaking process, the rational use of cationic starch is one of the important means to improve paper quality and reduce production costs.

[0004] However, in the existing papermaking process, the feed pump in the stock tank used for cationic starch pulping is only activated when making paper, and is in a stopped state when not making paper. Due to the characteristics of starch, it will gradually settle when not in use. In addition, due to the long downtime, the interval between making paper is generally about 4 hours, which causes starch deposition in the feed pump. When re-activated, the feed pump cannot be started normally and often trips. Electricians are required to reset it on site, and manual cleaning of the feed pump is required, which is time-consuming and laborious. In addition, the feed pump is difficult to start, has large vibrations after starting, and has a high maintenance frequency. In view of the above situation, it is urgent to transform the existing feed pump system to effectively improve production efficiency. [Contents of the utility model]

[0005] The utility model provides a control system for cationic starch pulping of a paper machine. By circulating a control pipeline, the cationic starch pulping material is always in a flowing state, effectively preventing the problem of starch deposition in the pipe when the pump is stopped without making material and causing bad material to jam the pump, thereby ensuring the reliable operation of the system.

[0006] The technical solution adopted by the utility model to solve its technical problems is:

[0007] A control system for cationic starch pulping in a paper machine, used to prevent starch from depositing in a pipeline and blocking a pump, comprising a cationic starch tank, a feed pump and a cooking pot, wherein the cationic starch tank, the feed pump and the cooking pot are sequentially connected in series through a pipeline, and the feed pump pumps the cationic starch slurry to be processed in the cationic starch tank into the cooking pot;

[0008] A feed valve is installed on the pipeline between the feed pump and the cooking pot to control the on-off of the pipeline and to control whether the feed pump supplies the cationic starch slurry to be processed to the cooking pot;

[0009] The pipeline between the feed pump and the feed valve is also connected in a bypass manner to a slurry circulation reflux pipe for closing the feed valve to stop feeding to the cooking pot and circulating the slurry pumped out by the feed pump into the top of the cationic starch tank to prevent starch deposition in the pipeline and tank body and pump jam; the slurry circulation reflux pipe is equipped with a reflux valve for controlling the on-off of the pipeline and for closing the slurry circulation reflux pipe for feeding the cooking pot to stop the reflux circulation.

[0010] Preferably, the top of the cationic starch tank is also connected to a feeding pipe for feeding external cationic starch slurry into the tank body, and the feeding pipe is provided with a feeding valve for controlling the on-off of the pipeline.

[0011] Preferably, the material valve is an automatically controlled pneumatic valve.

[0012] Preferably, the reflux valve is an automatically controlled pneumatic valve.

[0013] Preferably, the feed pump is a variable frequency pump that adaptively adjusts the pump outflow rate according to the working state. After the reflux valve is opened and the slurry circulation reflux pipe refluxes through, the speed of the feed pump in the circulation state is reduced to half of that when feeding the cooking pot.

[0014] The beneficial effects of the utility model are:

[0015] In view of the intermittent characteristics of the slurry preparation of cationic starch stock solution, the pipeline system of the feed pump is modified, a slurry circulation reflux pipe is added to the outlet pipe of the feed pump, and an automatically controlled pneumatic valve is added to the slurry circulation reflux pipe and the feed pipe respectively. The feed pump is set to the normally open state. When making materials, the feeding valve on the feed pipe is automatically opened, and the reflux valve on the slurry circulation reflux pipe is automatically closed. After the materials are made, the feeding valve is closed and the reflux valve is opened. In this way, the cationic starch slurry will circulate in the pipe without precipitation. The feed pump keeps circulating, and the slurry will not precipitate. The pipeline does not need to be manually flushed, and the material can be made in the normal procedure. It effectively prevents the starch deposition in the pipe corresponding to the feed pump when no material is made, causing the problem of bad material and pump jam, and ensures the normal supply of the pipeline and the stability and reliability of the system.

Brief Description of the Drawings

[0016] Figure 1 It is a schematic diagram of the system principle of the utility model. [Specific implementation method]

[0017] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0018] A control system for cationic starch pulping in a paper machine is used to prevent starch from depositing in the pipeline and blocking the pump. Figure 1 As shown, the invention comprises a cationic starch tank 1, a feed pump 2 and a cooking pot 3, which are connected in series in sequence through pipelines. The feed pump 2 pumps the cationic starch slurry to be processed in the cationic starch tank 1 into the cooking pot 3; a feed valve 4 for controlling the on-off of the pipeline and controlling whether the feed pump 2 supplies the cationic starch slurry to be processed to the cooking pot 3 is installed on the pipeline between the feed pump 2 and the cooking pot 3; a slurry circulation reflux pipe 5 for closing the feed valve 4 to stop feeding the cooking pot 3 and circulating the slurry pumped out by the feed pump 2 from the top of the cationic starch tank 1 to prevent starch deposition in the pipeline and the tank body and the pump from getting stuck is also installed on the slurry circulation reflux pipe 5, which controls the on-off of the pipeline and is used to close the slurry circulation reflux pipe 5 for feeding the cooking pot 3 to stop the reflux circulation.

[0019] Continue as Figure 1 As shown, a feeding pipe 7 for feeding external cationic starch slurry into the tank body is also connected to the top of the cationic starch tank 1, and a feeding valve 8 for controlling the on-off of the pipeline is arranged on the feeding pipe 7. Among them, the feeding valve 8, the material valve 4 and the reflux valve 6 are all automatically controlled pneumatic valves. The feed pump 2 is a variable frequency pump that adjusts the pump flow rate according to the working state. When working, after the reflux valve 6 is opened and the slurry circulation reflux pipe 5 refluxes through, the speed of the feed pump 2 in the circulation state is reduced to half of that when feeding to the cooking pot 3.

[0020] In this embodiment, in view of the intermittent characteristics of the existing cationic starch stock solution pulping and making materials, when the cationic starch is stationary, precipitation will occur, and the precipitated starch will adsorb the rotor of the feed pump 2, thereby affecting the operation of the pump. Therefore, the starch precipitation problem must be solved, and the solution to the precipitation is that as long as the material is in a flowing state, precipitation will not occur. Therefore, the pipeline system of the feed pump 2 is modified, and a slurry circulation reflux pipe 5 for returning the material to the top of the cationic starch tank 1 is added to the outlet pipe of the feed pump 2, and an automatically controlled pneumatic valve is added to the slurry circulation reflux pipe 5 and the feed pipeline respectively, and the feed pump 2 is set to a normally open state. When making materials, the feed valve 4 on the feed pipeline is automatically opened, and the reflux valve 6 on the slurry circulation reflux pipe 5 is automatically closed. After the material is made, the feed valve 4 is closed and the reflux valve 6 is opened. In this way, since the feed pump 2 is always in circulation, the cationic starch slurry circulates in the pipe without precipitation, and the pipe does not need to be manually flushed. This effectively prevents starch deposition in the pipe corresponding to the feed pump 2 when the material is not being made, causing problems such as material damage and pump jam, thereby ensuring the normal feeding of the pipe and the stability and reliability of the system.

[0021] The above-described embodiments are only preferred embodiments of the present invention and are not intended to limit the scope of implementation of the present invention. All equivalent changes made based on the shape, structure and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A control system for cationic starch pulping in a paper machine, used to prevent starch from depositing in the pipeline and causing the pump to get stuck, characterized in that: It comprises a cationic starch tank, a feed pump and a cooking pot, wherein the cationic starch tank, the feed pump and the cooking pot are sequentially connected in series through pipelines, and the feed pump pumps the cationic starch slurry to be processed in the cationic starch tank into the cooking pot; A feed valve is installed on the pipeline between the feed pump and the cooking pot to control the on-off of the pipeline and to control whether the feed pump supplies the cationic starch slurry to be processed to the cooking pot; The pipeline between the feed pump and the feed valve is also connected in a bypass manner to a slurry circulation reflux pipe for closing the feed valve to stop feeding to the cooking pot and circulating the slurry pumped out by the feed pump into the top of the cationic starch tank to prevent starch deposition in the pipeline and tank body and pump jam; the slurry circulation reflux pipe is equipped with a reflux valve for controlling the on-off of the pipeline and for closing the slurry circulation reflux pipe for feeding the cooking pot to stop the reflux circulation.

2. A control system for cationic starch pulping in a paper machine according to claim 1, characterized in that: The top of the cationic starch tank is also connected with a feeding pipe for feeding external cationic starch slurry into the tank body, and the feeding pipe is provided with a feeding valve for controlling the on-off of the pipeline.

3. A control system for cationic starch pulping in a paper machine according to claim 1, characterized in that: The material valve is an automatically controlled pneumatic valve.

4. A control system for cationic starch pulping in a paper machine according to claim 1, characterized in that: The reflux valve is an automatically controlled pneumatic valve.

5. A control system for cationic starch pulping in a paper machine according to claim 1, characterized in that: The feed pump is a variable frequency pump that adaptively adjusts the pump outflow according to the working state. After the reflux valve is opened and the slurry circulation reflux pipe refluxes through, the speed of the feed pump in the circulation state is reduced to half of that when feeding the cooking pot.

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