Liquid material conveying equipment and control method thereof

Abstract

The invention discloses liquid material conveying equipment and a control method thereof. The liquid material conveying equipment comprises a main conveying pipeline; a transfer pump; a bypass duct; a heater; a controller; a first valve and a second valve are respectively arranged at two ends of the main conveying pipeline; the two ends of the bypass pipeline are communicated with the main conveying pipeline; the controller is used for controlling opening and closing of the first valve and the second valve; when the first valve and the second valve are kept in a closed state, the bypass pipeline and the main conveying pipeline jointly form a closed annular pipeline, the conveying pump is used for driving backflow materials to circularly flow in the closed annular pipeline, and the heater is used for heating the backflow materials so that the backflow materials can heat the conveying pump; when the first valve and the second valve are kept in the open state, the conveying pump is used for driving the to-be-conveyed materials to be conveyed from the material input end to the material output end in the main conveying pipeline. The interior of the conveying pump is evenly and effectively heated through backflow materials, and therefore the conveying pump is prevented from being blocked.

Description

Technical Field

[0001] The present invention relates to the technical field of material transportation in the chemical industry, and particularly to a liquid material transportation device and its control method. Background Art

[0002] In the chemical industry, using a transfer pump to provide power for the flow of fluid materials in a transportation pipeline is an essential link in chemical production. Among many chemical raw materials or intermediate products, there will inevitably be some easily solidifiable materials such as high-viscosity organic substances, molten salts, and resins. During the transportation process, easily solidifiable materials are prone to solidification and caking due to temperature changes, or a relatively long residence time caused by too slow a flow rate, and other reasons.

[0003] For example, in a transportation system, due to the characteristic that the internal structure of the transfer pump cannot prevent materials from staying in the dead corner area of the pump, materials are likely to accumulate and then solidify, leading to the problem of blockage inside the pump. In addition, improper heat preservation measures for the material transportation system will also cause the easily solidifiable materials sensitive to temperature to solidify. Moreover, in the transportation system, the transportation process of materials may be unstable, resulting in too slow a flow rate of materials, or the transfer pump may stop midway due to unexpected situations, etc., which may all cause materials to solidify in local areas, resulting in material blockage. Once the materials solidify and block, parts such as the impeller of the transfer pump, the pump chamber, and the inner wall of the pipeline are extremely likely to be blocked, causing the entire transportation system to malfunction, and even seriously damaging the transportation equipment.

[0004] Traditional ways to solve the problem of material solidification in the transfer pump mostly involve heat preservation and heating of the entire transportation pipeline to prevent the materials in the transportation pipeline from solidifying due to too low a temperature; or configuring a stirring device to stir the easily solidifiable materials to prevent the materials from solidifying. However, the above methods for solving material solidification consume too much energy and have limited effects on solving the blockage problem at the position of the transfer pump. And most transfer pumps are processed after blockage occurs, which is not only time-consuming and laborious, but may also cause production interruption. Moreover, the pump body and pipeline of the transfer pump may be damaged during the blockage occurrence process or the blockage treatment process, affecting the service life of the equipment. Summary of the Invention

[0005] The purpose of the present invention is to provide a liquid material transportation device and its control method, which can effectively avoid the problem of blockage occurring in the transfer pump during the transportation of easily solidifiable materials, and is beneficial to extending the service life of the transfer pump.

[0006] To solve the above technical problems, the present invention provides a liquid material transportation device, including a main transportation pipeline; a transfer pump arranged on the main transportation pipeline; a bypass pipeline; a heater and an injection port for injecting reflux materials are arranged on the bypass pipeline; a controller;

[0007] Wherein, a first valve and a second valve are respectively arranged at the material input end and the material output end of the main conveying pipeline; the first end of the bypass pipeline is communicated with the section between the first valve on the main conveying pipeline and the input end of the conveying pump; the second end of the bypass pipeline is communicated with the section between the second valve on the main conveying pipeline and the output end of the conveying pump;

[0008] The controller is used to control the opening and closing of the first valve and the second valve;

[0009] When the first valve and the second valve are kept in a closed state, the bypass pipeline and the main conveying pipeline jointly form a closed annular pipeline, the conveying pump is used to drive the reflux material to circulate in the closed annular pipeline, and the heater is used to heat the reflux material so that the reflux material heats the conveying pump;

[0010] When the first valve and the second valve are kept in an open state, the conveying pump is used to drive the material to be conveyed from the material input end to the material output end in the main conveying pipeline.

[0011] In an optional embodiment of the present application, the reflux material is a solvent whose melting point is lower than that of the material to be conveyed and whose solubility in the material to be conveyed is not less than a set solubility;

[0012] And / or, the reflux material is the material to be conveyed.

[0013] In an optional embodiment of the present application, a third valve and a fourth valve are respectively arranged at the first end and the second end of the bypass pipeline; and the third valve, the fourth valve, the first valve and the second valve are all valves with adjustable opening degrees.

[0014] In an optional embodiment of the present application, a material receiving device is communicated with the material output end of the main conveying pipeline; the second valve is arranged between the material output end of the main conveying pipeline and the material receiving device;

[0015] A liquid discharging device is also communicated with the material output end of the main conveying pipeline; the inlet of the liquid discharging device is lower than the central height of the conveying pump; a fifth valve is arranged between the second end of the main conveying pipeline and the liquid discharging device.

[0016] In an optional embodiment of the present application, a temperature detection device is also arranged at the input end of the conveying pump; a pressure measuring device and a flow meter are also arranged at the output end of the conveying pump.

[0017] A control method for a liquid material conveying device, which is applied to the liquid material conveying device as described in any one of the above, the control method includes:

[0018] Control the first valve and the second valve to remain closed;

[0019] When the closed annular pipeline formed by the bypass pipeline and the main conveying pipeline is filled with the reflux material, control the conveying pump and the heater to start working to drive the heated reflux material to circulate in the closed annular pipeline;

[0020] When the conveying pump is heated to the set temperature value, control the first valve and the second valve to open so that the conveying pump drives the material to be conveyed to flow in the main conveying pipeline.

[0021] In an optional embodiment of the present application, the process of heating the conveying pump to the set temperature value includes:

[0022] Real-time collect the temperature data of the reflux material at the input end of the conveying pump;

[0023] When the temperature data reaches the set temperature range, keep the heating power of the heater unchanged, and continuously drive the reflux material to circulate in the closed annular pipeline for a set duration through the conveying pump; wherein, the minimum boundary temperature of the set temperature range is higher than the melting point temperature of the material to be conveyed.

[0024] In an optional embodiment of the present application, after controlling the first valve and the second valve to open, it further includes:

[0025] Control the first set opening ratio satisfied between the opening degree of the first valve and the opening degree of the third valve, and the second set opening ratio satisfied between the opening degree of the second valve and the opening degree of the fourth valve;

[0026] Real-time detect the material temperature data at the input end position of the conveying pump, the material pressure data and the material flow data at the output end position of the conveying pump;

[0027] Judge whether there is at least one of the fluid temperature data being less than the set temperature threshold, the fluid pressure data being less than the set pressure threshold, and the flow data being less than the set flow threshold; if so, increase the heating power of the heater and output an alarm prompt.

[0028] In an optional embodiment of the present application, after controlling the first valve and the second valve to open, it further includes:

[0029] When receiving a long-term shutdown instruction, control the first valve and the second valve to close, open the fifth valve, and control the heater and the conveying pump to stop;

[0030] When the material at the output end of the delivery pump is completely drained, close the fifth valve and fill the closed annular pipeline with the reflux material; wherein, the reflux material is a solvent with a melting point lower than that of the material to be delivered and a solubility in the material to be delivered not less than the set solubility.

[0031] Control the delivery pump and the heater to start working.

[0032] When the reflux material flows and circulates in the closed annular pipeline for a second set duration, control the delivery pump and the heater to stop working.

[0033] Open the fifth valve to allow the reflux material to flow into the liquid discharge device.

[0034] In an optional embodiment of the present application, after controlling the first valve and the second valve to open, it further includes:

[0035] When a short-term shutdown instruction is received, control the first valve and the second valve to close and keep the delivery pump and the heater in the starting working state until a restart instruction is received, then control the first valve and the second valve to open.

[0036] The liquid material delivery device and its control method provided by the present invention. The liquid material delivery device includes a main delivery pipeline; a delivery pump arranged on the main delivery pipeline; a bypass pipeline; a heater and an injection port for injecting reflux material are arranged on the bypass pipeline; a controller; wherein, a first valve and a second valve are respectively arranged at the material input end and the material output end of the main delivery pipeline; the first end of the bypass pipeline is communicated with the section between the first valve and the input end of the delivery pump on the main delivery pipeline; the second end of the bypass pipeline is communicated with the section between the second valve and the output end of the delivery pump on the main delivery pipeline; the controller is used to control the opening and closing of the first valve and the second valve; when the first valve and the second valve remain closed, the bypass pipeline and the main delivery pipeline together form a closed annular pipeline, the delivery pump is used to drive the reflux material to circulate in the closed annular pipeline, and the heater is used to heat the reflux material so that the reflux material heats the delivery pump; when the first valve and the second valve remain open, the delivery pump is used to drive the material to be delivered to be transported from the material input end to the material output end in the main delivery pipeline.

[0037] In this application, a bypass pipeline is configured on the main conveying pipeline provided with a conveying pump, and a heater is provided on the bypass pipeline. When the first valve and the second valve at both ends of the main conveying pipeline are closed, a closed annular pipeline can be formed between the bypass pipeline and the main conveying pipeline, and both the heater and the conveying pump are located on this circulating reflux channel. Thus, after filling the closed annular pipeline with reflux materials through the injection port on the bypass pipeline, the conveying pump can be used to drive the reflux materials to circulate in the closed annular pipeline. At the same time, the heater can heat the reflux materials, so that the heated reflux materials can fully contact the impeller, pump cavity, etc. in the conveying pump, thereby realizing sufficient and effective heating of the conveying pump. Therefore, in practical applications of the liquid material conveying equipment in this application, before conveying the easily solidifiable material to be conveyed, the conveying pump can be preheated by using the bypass pipeline, the heater and the reflux materials, and when the temperature of the material to be conveyed is too low during the conveying process in the main conveying pipeline and there is a possibility of material solidification, the conveying pump can also be heated by using the bypass pipeline, the heater and the reflux materials, so as to effectively avoid blockage of the impeller and pump cavity of the conveying pump due to material solidification and damage to the conveying pump, and avoid frequent shutdowns for cleaning the conveying pump. And in this application, the heating is carried out from the inside of the conveying pump. Compared with the traditional heating from the outside of the conveying pump, the heating of the conveying pump in this application is more uniform and effective, thus effectively avoiding blockage of the conveying pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions of the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0039] Figure 1 It is a schematic structural diagram of the liquid material conveying equipment provided by the embodiment of this application;

[0040] Figure 2 It is a schematic flow diagram of the control method of the liquid material conveying equipment provided by the embodiment of this application;

[0041] In the drawings: 1 is the main conveying pipeline, 11 is the conveying pump, 12 is the mixer, 13 is the temperature sensor, 14 is the pressure measuring device, 15 is the flow meter, 2 is the bypass pipeline, 21 is the heater, 22 is the buffer tank, 31 is the first valve, 32 is the second valve, 33 is the third valve, 34 is the fourth valve, 35 is the fifth valve, 4 is the controller, 5 is the material generating device, 6 is the material receiving device, 7 is the liquid discharging device. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0042] The core of the present invention is to provide a liquid material conveying device and a control method for the liquid material conveying device, which can fully heat the inside of the conveying pump and effectively avoid the problem of blockage of the conveying pump.

[0043] In order to enable those skilled in the art to better understand the solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0044] As Figure 1 shown, Figure 1 is a schematic structural diagram of the liquid material conveying device provided by the embodiment of the present application.

[0045] In a specific embodiment of the present application, the liquid material conveying device may include:

[0046] The main conveying pipeline 1; the conveying pump 11 arranged on the main conveying pipeline 1; the bypass pipeline 2; the heater 21 and the injection port for injecting the reflux material are arranged on the bypass pipeline 2; the controller 4;

[0047] Among them, the material input end and the material output end of the main conveying pipeline 1 are respectively provided with the first valve 31 and the second valve 32; the first end of the bypass pipeline 2 is communicated with the section between the first valve 31 and the input end of the conveying pump 11 on the main conveying pipeline 1; the second end of the bypass pipeline 2 is communicated with the section between the second valve 32 and the output end of the conveying pump 11 on the main conveying pipeline 1;

[0048] The controller 4 is used to control the opening and closing of the first valve 31 and the second valve 32;

[0049] When the first valve 31 and the second valve 32 are kept in the closed state, the bypass pipeline 2 and the main conveying pipeline jointly form a closed annular pipeline, the conveying pump 11 is used to drive the reflux material to circulate in the closed annular pipeline, and the heater 21 is used to heat the reflux material so that the reflux material heats the conveying pump 11;

[0050] When the first valve 31 and the second valve 32 are kept in the open state, the conveying pump 11 is used to drive the material to be conveyed from the material input end to the material output end in the main conveying pipeline 1.

[0051] As Figure 1As shown, the main conveying pipeline 1 in this embodiment can be a section of pipeline for conveying the material to be conveyed in liquid form, or a pipeline for conveying the material to be conveyed from one device to another device. In short, it should be a pipeline provided with a conveying pump 11; and this conveying pipeline can be a straight pipeline or a pipeline with a bending and turning structure, and there is no specific limitation in this application. On the main conveying pipeline 1, the end where the material to be conveyed flows in is the material input end of the main conveying pipeline 1, and the end where the material to be conveyed flows out is the material output end of the main conveying pipeline 1; generally, the material input end of the main conveying pipeline 1 is connected to a material generating device 5, and the material output end is connected to a material receiving device 6. A first valve 31 is provided at the material input end of the main conveying pipeline 1 for controlling the inflow of the material to be conveyed into the main conveying pipeline 1, and a second valve 32 is provided at the material output end for controlling the outflow of the material to be conveyed from the main conveying pipeline 1.

[0052] On this basis, a bypass pipeline 2 is further configured for the main conveying pipeline 1. The two ends of the bypass pipeline 2 are respectively communicated with the main conveying pipeline 1. Among them, the first end of the bypass pipeline 2 is communicated with the section between the first valve 31 and the input end of the conveying pump 11 on the main conveying pipeline 1. The first end of the bypass pipeline 2 should be connected to the position on the main conveying pipeline 1 as close as possible to the first valve 31, and the second end of the bypass pipeline 2 should be communicated with the section between the output end of the output pump and the second valve 32 on the main conveying pipeline 1. The second end of the bypass pipeline 2 should also be connected to the position on the main conveying pipeline 1 as close as possible to the second valve 32, so as to heat the main conveying pipeline 1 to the greatest extent.

[0053] In addition, an injection port is provided on the bypass pipeline 2 for injecting the reflux material into the bypass pipeline 2. In practical applications, a buffer tank 22 can be connected to the injection port. A liquid discharge port connected to the injection port is provided at the bottom of the buffer tank 22, and the height of the liquid discharge port should be at least 1 m higher than the center height of the conveying pump 11 (that is, the height of the rotation center axis of the impeller, and this center axis is generally in the horizontal direction), so as to ensure that the reflux material can be fully injected into the main conveying pipeline 1 through the bypass pipeline 2. A heater 21 is provided on the bypass pipeline 2 for heating the reflux material flowing through the heater 21.

[0054] Further optionally, in this embodiment, it is not excluded that the bypass pipeline 2 passes through the buffer tank 22, and at the same time, the heater 21 is directly arranged inside the buffer tank 22, that is, the heater 21 directly heats the reflux material in the buffer tank 22, and the reflux material in the buffer tank 22 can also circulate in the bypass pipeline 2 at the same time. Of course, the heater 21 and the buffer tank 22 can also be independently arranged in different sections of the bypass pipeline 2. And the heater 21 can be a heating device built inside the bypass pipeline 2, or can wrap and heat the reflux material in the bypass pipeline 2 from the outside of a certain section of the bypass pipeline 2. No specific limitation is made in this application for this.

[0055] In the actual application process, when it is necessary to heat the delivery pump 11, the first valve 31 and the second valve 32 can be controlled to be closed at the same time, that is, the main delivery pipeline 1 does not temporarily deliver the material to be delivered; at this time, a closed annular pipeline can be formed between the bypass pipeline 2 and the main delivery pipeline 1; and there are also the delivery pump 11 and the heater 21 on the closed annular pipeline; thus, if the closed annular pipeline is already completely filled with reflux material at this time, the controller 4 directly controls the delivery pump 11 and the heater 21 to start synchronously. The delivery pump 11 can make the reflux material circulate in the closed annular pipeline, and the heater 21 can heat the circulating reflux material. When the temperature of the reflux material is heated high enough, as it circulates in the closed annular pipeline, the reflux material can be in full contact with the internal structure of the delivery pump 11, thereby heating the delivery pump 11. After the temperature of the delivery pump 11 is heated high enough, the first valve 31 and the second valve 32 are opened, and the main delivery pipeline 1 can normally deliver the material to be delivered. At this time, because the temperature of the delivery pump 11 itself is relatively high, the solidification and blockage of the material to be delivered in the delivery pump 11 can be effectively avoided; at the same time, while the reflux material heats the delivery pump 11, it will also heat the main delivery pipeline 1, thereby effectively avoiding the solidification and blockage of the material to be delivered in the delivery section of the entire main delivery pipeline 1; it can not only ensure the smooth and effective delivery of the material to be delivered, but also avoid equipment damage caused by the solidification and blockage of the material in the delivery pump 11.

[0056] Based on the above discussion, the reflux material injected into the bypass pipeline 2 through the injection port in this application can directly use the same material as the material to be delivered, or can be a solvent whose solubility in the material to be delivered is not lower than the set solubility and whose melting point is lower than that of the material to be delivered, that is, a solvent that has a good solubility in the material to be delivered and is not easy to solidify; in actual applications, a suitable reflux material can be selected based on different working conditions.

[0057] It can be understood that after the transfer pump 11 and the main transfer pipeline 1 are heated by the reflux material, the controller 4 can open the first valve 31 and the second valve 32, and the main transfer pipeline 1 can start to normally transfer the material to be transferred. When the material to be transferred is flowing normally in the main transfer pipeline 1, if the bypass pipeline 2 forms a dead end relative to the main transfer pipeline 1, the reflux material in the bypass pipeline 2 will remain stationary and gradually cool down or even solidify. Then, if it is necessary to restart the heater 21 to heat the reflux material later, it may not be able to flow due to the solidification of the reflux material, and thus the restart of heating will fail.

[0058] Therefore, in an optional embodiment of the present application, a third valve 33 and a fourth valve 34 can be further provided at the first end and the second end of the bypass pipeline 2 respectively, and the first valve 31, the second valve 32, the third valve 33, and the fourth valve 34 are all valves with adjustable opening degrees.

[0059] Thus, when the main transfer pipeline 1 is normally transferring the material to be transferred, by reasonably controlling the opening degree ratio between the first valve 31 and the third valve 33, and the opening degree ratio between the third valve 33 and the fourth valve 34, a part of the material to be transferred can be mixed with the material in the bypass pipeline 2 to circulate between the bypass pipeline 2 and the main transfer pipeline 1 while the material to be transferred is flowing in the main transfer pipeline 1. Obviously, the heater 21 is also kept in the heating state at this time. This can not only ensure that the material in the bypass pipeline 2 is always in a flowing and non-solidifying state, but also continuously heat the material to be transferred in the main transfer pipeline 1 by the heater 21, further avoiding the problem of blockage in the main transfer pipeline 1.

[0060] Optionally, a mixer 12 can be further provided at a position on the main transfer pipeline 1 close to the first valve 31, and the first end of the bypass pipeline 2 is connected to the main transfer pipeline 1 through the mixer 12. Thus, when the main transfer pipeline 1 is normally transferring the material to be transferred, the heated material to be transferred in the bypass pipeline 2 can flow into the main transfer pipeline 1 after being fully mixed in the mixer 12, thereby greatly improving the uniformity of the temperature of the material to be transferred.

[0061] In addition, as mentioned above, the reflux material in the present application can be the material to be transferred or the solvent of the material to be transferred; taking the reflux material as the solvent as an example, after the main transfer pipeline 1 and the transfer pump 11 are heated, when the first valve 31 and the second valve 32 are opened and the main transfer pipeline 1 starts to normally transfer the material to be transferred, both the main transfer pipeline 1 and the bypass pipeline 2 are filled with the solvent; if the material receiving device 6 connected to the material output end of the main transfer pipeline 1 requires that the received material to be transferred is pure material without mixing with the solvent, obviously the material discharged from the material output end of the main transfer pipeline 1 does not meet the requirements at this time.

[0062] Therefore, in another optional embodiment of the present application, a liquid discharging device 7 is further connected to the material output end of the main conveying pipeline 1, and a fifth valve 35 is further provided between the liquid discharging device 7 and the material output end. Thus, after the main conveying pipeline 1 and the conveying pump 11 are heated, the fifth valve 35 can be opened first to discharge the reflux material in the bypass pipeline 2 and the main conveying pump 11 to the liquid discharging device 7 by using the conveying pump 11. When the reflux material in the main conveying pipeline 1 is completely discharged, the fifth valve 35 can be closed, and the first valve 31 and the second valve 32 can be opened to start the normal conveying of the material to be conveyed from the material generating device 5 to the material receiving device 6.

[0063] Certainly, the liquid discharging device 7 in this embodiment can also be used as a recovery device for recovering the cleaning waste liquid, which is the residual material in the conveying pump 11 and the main conveying pipeline 1, after the conveying of the material to be conveyed is completed.

[0064] Furthermore, in order to ensure that the liquid output from the conveying pump 11 can be smoothly discharged into the liquid discharging device 7, the inlet height of the liquid discharging device 7 should be lower than the center height of the conveying pump 11.

[0065] As described above, in order to ensure the safety of the entire liquid material conveying equipment during the material conveying process, a temperature detection device can be further provided at the input end of the conveying pump 11; a pressure measuring device 14 and a flow meter 15 are provided at the output end of the conveying pump 11.

[0066] When any one of the three conditions occurs, that is, the temperature data measured by the temperature detection device is too low, the pressure measured by the pressure measuring device 14 is too small, or the flow data measured by the flow meter 15 is too small, it indicates that the material to be conveyed has a high viscosity and there is a risk of solidification. The heater 21 can be controlled to increase the heating power. At the same time, the controller 4 can also send an alarm to the staff for timely supervision and inspection to avoid safety accidents.

[0067] In summary, in the present application, a bypass pipeline is configured on the main conveying pipeline provided with a conveying pump, and a heater is provided on the bypass pipeline. When the first valve and the second valve at both ends of the main conveying pipeline are closed, a closed annular pipeline can be formed between the bypass pipeline and the main conveying pipeline, and both the heater and the conveying pump are located on this circulation return channel. Thus, after filling the closed annular pipeline with return material through the injection port on the bypass pipeline, the conveying pump can be used to drive the return material to circulate in the closed annular pipeline. At the same time, the heater can heat the return material, so that the heated return material comes into full contact with the impeller, pump chamber, etc. inside the conveying pump, thereby realizing sufficient and effective heating of the conveying pump. Therefore, in practical applications of the liquid material conveying equipment in the present application, before conveying the easily solidifiable material to be conveyed, the bypass pipeline, the heater, and the return material can be used to preheat the conveying pump, and when the temperature of the material to be conveyed is too low during the conveying process in the main conveying pipeline and there is a possibility of material solidification, the bypass pipeline, the heater, and the return material can also be used to heat the conveying pump, thereby effectively avoiding blockage of the impeller and pump chamber of the conveying pump due to material solidification and damage to the conveying pump, and avoiding frequent shutdowns for cleaning the conveying pump. And the present application heats from the inside of the conveying pump. Compared with the traditional external heating of the conveying pump, the heating of the conveying pump in the present application is more uniform and effective, thus effectively avoiding blockage of the conveying pump.

[0068] Based on any of the above embodiments, the present application further provides an embodiment of a control method for a liquid material conveying equipment, and this control method for the liquid material conveying equipment is applied to the liquid material conveying equipment described in any of the above embodiments. As Figure 2 shown, in a specific embodiment of the present application, the control method for the liquid material conveying equipment may include:

[0069] S11: Control the first valve and the second valve to remain closed;

[0070] S12: When the closed annular pipeline jointly formed by the bypass pipeline and the main conveying pipeline is filled with return material, control the conveying pump and the heater to start working to drive the heated return material to circulate in the closed annular pipeline;

[0071] S13: When the conveying pump is heated to the set temperature value, control the first valve and the second valve to open so that the conveying pump drives the material to be conveyed to flow in the main conveying pipeline.

[0072] Referring to Figure 1 and Figure 2, when the first valve 31 and the second valve 32 are kept closed, a closed annular pipeline can be formed between the bypass pipeline 2 and the main conveying pipeline 1. If the closed annular pipeline is filled with reflux materials at this time, the heater 21 and the conveying pump 11 can be started, so that the reflux materials circulate in the closed annular pipeline. At the same time, the heater 21 heats the reflux materials, so that the reflux materials heat the main conveying pipeline 1 and the conveying pump 11 through which they flow. When the main conveying pipeline 1 and the conveying pump 11 are heated, the first valve 31 and the second valve 32 can be opened, so that the main conveying pipeline 1 starts to normally convey the materials to be conveyed.

[0073] In this application, the heating device on the bypass pipeline 2 can heat the main conveying pipeline 1 and the conveying pump 11 under a variety of different working conditions. For example, before the main conveying pipeline 1 starts to convey materials, the main conveying pipeline 1 and the conveying pump 11 can be preheated; it can also be that when the temperature of the materials to be conveyed is too low during the normal conveying process of the main conveying pipeline 1, the main conveying pipeline 1 and the conveying pump 11 are started to be heated; it can also be the heating carried out to keep the temperature of the main conveying pipeline 1 and the conveying pump 11 when the material generating device 5 stops for a short time; it can also be the heating for flushing the residual materials in the conveying pump 11 after the materials to be conveyed are conveyed.

[0074] For the heating under different working conditions, the types of the corresponding reflux materials can also be different accordingly. The following takes specific embodiments to illustrate the heating methods under different working conditions.

[0075] Taking the preheating of the conveying pump 11 before the main conveying pipeline 1 starts to normally convey the materials to be conveyed as an example, after controlling the first valve 31 and the second valve 32 to be kept closed, neither the bypass pipeline 2 nor the main conveying pipeline 1 is filled with any materials at this time. At this time, reflux materials need to be injected through the injection port on the bypass pipeline 2. The reflux materials injected at this time can be the same materials as the materials to be conveyed, or the solvent of the materials to be conveyed. If a buffer tank 22 is connected to the injection port of the bypass pipeline 2, when the drain port connected to the bottom end of the buffer tank 22 is filled with reflux materials, it can be considered that both the bypass pipeline 2 and the main conveying pipeline 1 are filled with reflux materials.

[0076] When the closed annular pipeline is filled with reflux materials, the heater 21 and the conveying pump 11 start to work simultaneously. However, the temperature inside the conveying pump 11 cannot be measured, and only the temperature of the conveying pump 11 can be indirectly determined by measuring the temperature of the reflux materials to see if it reaches the set temperature value.

[0077] In order to ensure that the temperature of the conveying pump 11 can reach the required set temperature value, this heating process can further include:

[0078] S131: Real-time collect the temperature data of the reflux material at the input end of the delivery pump;

[0079] S132: When the temperature data is within the set temperature range, keep the heating power of the heater unchanged, and continuously drive the reflux material to circulate in the closed annular pipeline for a set duration through the delivery pump; wherein, the minimum boundary temperature of the set temperature range is higher than the melting point temperature of the material to be delivered;

[0080] For example, the temperature difference between the minimum boundary temperature of the set temperature range and the melting point temperature of the material to be delivered may be not less than 30 °C.

[0081] During the process of the reflux material circulating in the closed annular pipeline, the reflux material can be gradually heated under the heating of the heater 21. When the temperature data measured by the temperature sensor 13 at the input end of the delivery pump 11 reaches within the set temperature range, it means that the temperature of the reflux material has reached the set temperature range, but the temperature of the delivery pump 11 does not necessarily reach this set temperature range. Therefore, the heating power of the heater 21 can be continuously kept unchanged, and the circulation of the reflux material can be continuously maintained for at least the set duration to ensure that the reflux material has enough time to exchange heat with the delivery pump 11, so that the internal temperature of the delivery pump 11 is heated to the set temperature value.

[0082] It should be noted that the temperature difference between the minimum boundary temperature of the set temperature range value in this embodiment and the melting point temperature of the material to be delivered is at least not less than 30 °C, so as to fully ensure that the material to be delivered will not solidify when flowing through the delivery pump 11. On this basis, the set temperature value that the delivery pump 11 needs to be heated can be the minimum boundary temperature of the above set temperature range, that is to say, the reflux material needs to be heated to a temperature not less than the set temperature value required by the delivery pump 11, so as to ensure that the delivery pump 11 can be heated to the set temperature value by the reflux material.

[0083] The above is described by taking the working condition of preheating and heating the delivery pump 11 as an example. In actual application, even if the delivery pump 11 is preheated and heated to the set temperature value, during the process of the main delivery pipeline 1 starting to normally deliver the material to be delivered, the reflux material circulating in the bypass pipeline 2 and the main delivery pipeline 1 can also be used to continuously heat the material to be delivered, that is, the continuous heating under the stable operation condition.

[0084] The continuous heating process under the stable operation condition may include:

[0085] S1411: Control the first valve opening and the third valve opening to satisfy the first set opening ratio, and the second valve opening and the fourth valve opening to satisfy the second set opening ratio;

[0086] S1412: Detect the fluid temperature data at the input end position of the transfer pump, the fluid pressure data and the flow rate data at the output end position of the transfer pump 11 in real time;

[0087] S1413: Determine whether there is at least one of the fluid temperature data being less than the set temperature threshold, the fluid pressure data being less than the set pressure threshold, and the flow rate data being less than the set flow rate threshold; if so, increase the heating power of the heater and output an alarm prompt; if not, proceed to S1412.

[0088] In this embodiment, on the basis of keeping the first valve 31, the second valve 32, the third valve 33 and the fourth valve 34 all in the open state, control the first set opening ratio satisfied between the opening degree of the first valve 31 and the opening degree of the third valve 33, and the second set opening ratio satisfied between the opening degree of the second valve 32 and the opening degree of the fourth valve 34; thereby enabling a part of the material to be transported to be transported from the material input end of the main transport pipeline 1 to the material output end, while the other part flows in the closed annular pipeline formed by the main transport pipeline 1 and the bypass pipeline 2.

[0089] Obviously, within a period of time after the first valve 31 and the second valve 32 start to open, the return material in the original closed annular pipeline will mix with the material to be transported, and at this time the material flowing in the closed annular pipeline is the mixed material of the original return material and the material to be transported; after the first valve 31 and the second valve 32 are continuously opened for a period of time, the original return material is basically discharged from the main transport pipeline 1, and at this time the material flowing in the closed annular pipeline is completely the material to be transported. During this process, the heater 21 can maintain the state of continuously heating the material flowing in the bypass pipeline 2, and at this time the heating power of the heater 21 can be less than the heating power under the preheating heating condition, and specifically can be feedback-adjusted based on the material temperature data in the main transport pipeline 1; when the material temperature data in the main transport pipeline 1 is too low, it indicates that there is a risk of solidification of the material to be transported in the main transport pipeline 1, and the heating power of the heater 21 can be increased, on the contrary, when the material temperature data is too low, the heating power of the heater 21 can be reduced. In short, the temperature of the material to be transported can be maintained within a reasonable temperature range. Of course, when the material temperature data is too low, an alarm prompt can also be sent to the staff to remind the staff to check and determine whether there is an unreasonable setting of the heater 21 power or other problems, such as the failure of the pipeline heat preservation device, etc.

[0090] Meanwhile, it is also possible to perform pressure detection on the material at the output end of the transfer pump 11 in real time, and flow detection on the material output at the output end of the main transfer pipeline 1; when the material pressure data measured at the output end of the transfer pump 11 is too small, or the material flow data measured at the output end of the main transfer pipeline 1 is on the low side, it is very likely that the viscosity of the material in the transfer pump 11 has become relatively large or even there is a slight blockage. At this time, the heating power of the heater 21 can be increased, and an alarm prompt can be issued to remind the staff to check the reason.

[0091] Based on the above discussion, during the process of the entire liquid material transfer equipment maintaining a stable operating condition for transferring the material to be transferred, the material generating device 5 may need to temporarily stop inputting the material to be transferred into the main transfer pipeline 1 due to certain special circumstances. At this time, if the transfer pump 11 is directly shut down, it may cause the problem of material cooling and solidification in the main transfer pipeline 1. Therefore, during the process of the liquid material transfer equipment maintaining stable operation, it can further include:

[0092] When receiving a short-term shutdown instruction, control the first valve and the second valve to close, and keep the transfer pump and the heater in the starting working state until receiving a restart instruction, then control the first valve and the second valve to close.

[0093] It can be understood that the short-term shutdown instruction in this embodiment is also an instruction indicating that the material generating device 5 stops transferring the material to be transferred into the main transfer pipeline 1 for a short time. At this time, the first valve 31 and the second valve 32 can be directly closed, or the opening degrees of the third valve 33 and the fourth valve 34 can be appropriately adjusted. The heating power of the heater 21 can maintain the material temperature data in the main transfer pipeline 1 within the set temperature range, and at the same time, the working power of the output pump can also be appropriately reduced; when the material generating device 5 can re-transfer the material to be transferred into the main transfer pipeline 1, directly open the first valve 31 and the second valve 32, and readjust the operating state of the entire transfer equipment to the state under the stable operating condition.

[0094] After all the materials generated by the material generating device 5 are completely transferred, it can further include:

[0095] S1421: When receiving a long-term shutdown instruction, control the first valve and the second valve to close, open the fifth valve, and control the heater and the transfer pump to shut down;

[0096] S1422: When the material at the output end position of the transfer pump is drained, close the fifth valve, and fill the closed annular pipeline with reflux material; wherein, the reflux material is a solvent with a melting point lower than the material to be transferred and a solubility in the material to be transferred not less than the set solubility;

[0097] S1423: Control the transfer pump and the heater to start working;

[0098] S1424: When the reflux material flows and circulates in the closed annular pipeline for the second set duration, control the transfer pump and the heater to stop working;

[0099] S1424: Open the fifth valve to allow the reflux material to flow into the liquid discharge device.

[0100] It can be understood that the long-term shutdown instruction referred to in this embodiment is also an instruction indicating that the material generation device 5 is to be shut down for a long time. At this time, control the heating pump and the transfer pump 11 to stop, close the first valve 31 and the second valve 32, and open the fifth valve 35, so that at least part of the material in the main transfer pipeline 1 and the bypass pipeline 2 automatically discharges into the liquid discharge device 7 due to gravity. During this process, the opening degrees of the third valve 33 and the fourth valve 34 should also be opened to the maximum.

[0101] After the material in the pipeline section between the output end of the transfer pump 11 and the inlet of the liquid discharge device 7 is generally discharged into the liquid discharge device 7, there is generally still undischarged material left in the bypass pipeline 2 and the main transfer pipeline 1, and generally it is the same material as the material to be transferred; in order to remove this part of the material, the fifth valve 35 can be further closed, and the solvent of the material to be transferred is injected into the bypass pipeline 2 through the injection port, so that the closed annular pipeline formed by the main transfer pipeline 1 and the bypass pipeline 2 is filled, generally filled with the solvent dissolving the material to be transferred. At this time, restart the heater 21 and the transfer pump 11, so that the solvent is fully heated and flows in the closed annular pipeline, which is equivalent to cleaning the entire closed annular pipeline to a certain extent. After the solvent circulates in the closed annular pipeline for a period of time, for example, it can be 10 minutes, 15 minutes, 20 minutes, etc.; control the transfer pump 11 and the heater 21 to stop working, and open the fifth valve 35 to allow the solvent to flow into the liquid discharge device 7 for recovery.

[0102] It can be understood that the reflux material injected into the bypass pipeline 2 in this embodiment preferably selects the solvent of the material to be transferred, but the same material as the material to be transferred can also be used, as long as the reflux material has good fluidity and can smoothly flow into the liquid discharge device 7 when the heater 21 and the transfer pump 11 stop.

[0103] Based on any of the above embodiments, for the sake of easy understanding, the technical solutions in the present application will be further described below with specific embodiments.

[0104] In a coal-to-ethylene glycol plant, dimethyl oxalate can be transported to the ethylene glycol synthesis section by using the liquid material transportation equipment in the present application.

[0105] In an embodiment of the present application, taking dimethyl oxalate as the material to be conveyed as an example, the conveying process of the dimethyl oxalate is as follows:

[0106] 1) Start-up preheating stage:

[0107] Use methanol (i.e., the solvent of dimethyl oxalate) to preheat the conveying pump 11 as the reflux material. Before the system starts, ensure that the liquid discharge device 7 is at a low liquid level or no liquid level to receive the mixed liquid of methanol and dimethyl oxalate generated in the preheating stage. The buffer tank 22 is at an appropriate liquid level, and the amount of methanol filled in it can realize circulation in the bypass pipeline 2 and the main conveying pipeline 1 and preheat the conveying pump 11.

[0108] Close the first valve 31, the second valve 32, and the fifth valve 35, open the third valve 33 and the fourth valve 34, and let the methanol in the buffer tank 22 flow into the heater 21, the mixer 12, the conveying pump 11, the bypass pipeline 2, and the main conveying pipeline 1; the methanol circulates between the bypass pipeline 2 and the main conveying pipeline 1. The temperature control logic is as follows: The set temperature value is determined to be 85 °C. When the measured value of the temperature sensor 13 is less than 85 °C, the heater 21 works and heats the temperature of the methanol to above 85 °C; when the temperature of the methanol is between 85 and 90 °C, the output power of the heater 21 remains unchanged. When the temperature of the methanol is greater than 90 °C, the heater 21 is turned off.

[0109] The methanol circulates for 2 hours. If the measured value of the temperature sensor 13 remains between 85 and 90 °C, slowly open the first valve 31 and the fifth valve 35, while the second valve 32 remains closed, introduce dimethyl oxalate, and discharge the mixed liquid of methanol and dimethyl oxalate to the liquid discharge device 7 until the methanol in the bypass pipeline 2 and the main conveying pipeline 1 is discharged completely (specifically, it can be determined based on the detection of the material components received by the liquid discharge device 7). At this time, the qualified dimethyl oxalate solution circulates in the bypass pipeline 2 and the main conveying pipeline 1, then the fifth valve 35 can be closed and the second valve 32 can be opened.

[0110] Of course, after the methanol circulates for 2 hours, the second valve 32 can also be directly opened, while the fifth valve 35 is closed, so that the mixed liquid of methanol and dimethyl oxalate is directly discharged to the material receiving device 6, and the dimethyl oxalate is refined by the material receiving device 6.

[0111] 2) Stable operation stage:

[0112] In the stable operation stage, the temperature of the dimethyl oxalate is about 100 °C; the first valve 31, the second valve 32, the third valve 33, and the fourth valve 34 are all in the open state, and the temperature control logic is the same as that in the start-up preheating stage.

[0113] Closely monitor the material temperature data at the input end of the transfer pump 11 through the temperature sensor 13, monitor the material pressure value at the output end of the transfer pump 11 through the pressure measuring device, and monitor the material flow value at the output end of the main transfer pipeline 1 through the flowmeter 15. If there is a pressure drop, a flow rate drop, or both occur simultaneously, and their average value is less than 10% of the normal value, an alarm signal is sent to the operator, and the operator needs to confirm on-site whether the transfer pump 11 is blocked; if the transfer pump 11 is blocked, the set temperature value can be adjusted to 100 °C or even higher.

[0114] 3) Thermal standby stage of the transfer pump:

[0115] When the system outside the transfer pump 11 (such as the material generation device 5) stops for a short time, to avoid the cumbersome operation of starting and stopping the transfer pump 11, the first valve 31 and the second valve 32 can be closed, the opening degrees of the third valve 33 and the fourth valve 34 are adjusted, and the transfer pump 11 drives the dimethyl oxalate to circulate between the bypass pipeline 2 and the main transfer pipeline 1. The temperature control logic is the same as that in the start-up preheating stage. At this time, the set temperature value can be adjusted to 100 °C.

[0116] 4) Long-term shutdown stage:

[0117] When the entire production device is planned to be shut down for a long time, all the dimethyl oxalate in the equipment should be drained in time. In theory, after all the dimethyl oxalate in the equipment is drained, it should be rinsed with methanol or other solvents.

[0118] If it is necessary to drain the dimethyl oxalate transfer pump 11 separately, the following operations can be performed: close the first valve 31 and the second valve 32, the dimethyl oxalate in the transfer pump 11 circulates in the closed annular pipeline, open the fifth valve 35, and drain most of the dimethyl oxalate in the transfer pump 11 to the liquid discharge device 7. The transfer pump 11 stops for a short time, methanol is injected into the buffer tank 22, and the mixed solution of methanol and dimethyl oxalate circulates in the closed annular pipeline for 15 minutes and then is drained to the liquid discharge device 7.

[0119] The mixed solution of methanol and dimethyl oxalate can also be discharged to the material receiving device 6 through the second valve 32.

[0120] Based on the above discussion, in a urea plant, molten urea can also be transported to a granulator or a granulation tower by using the liquid material transportation equipment in this application.

[0121] In another embodiment of this application, taking the molten urea to be transported as an example, the transportation process of the molten urea is as follows:

[0122] 1) Start-up preheating stage:

[0123] Use a demineralized water preheating transfer pump 11. Before starting the equipment, ensure that the liquid discharge device 7 is at a low liquid level or has no liquid level to receive the mixed liquid of demineralized water and molten urea generated during the preheating stage. The buffer tank 22 is at an appropriate liquid level, and the amount of demineralized water filled in it can achieve circulation in the bypass pipeline 2 and the main transfer pipeline 1 and preheat the transfer pump 11.

[0124] Close the first valve 31, the second valve 32, and the fifth valve 35, and open the third valve 33 and the fourth valve 34. Let the demineralized water in the buffer tank 22 flow into the heater 21, the mixer 12, the transfer pump 11, and the corresponding pipeline system, and the demineralized water circulates between the reflux equipment and the pipeline. The temperature control logic is as follows: The set temperature value is determined to be 143 °C. When the measured value of the temperature sensor 13 is less than 143 °C, the heater 21 starts to work and heats the temperature of the demineralized water to above 143 °C; when the temperature of the demineralized water is between 143 and 147 °C, the output power of the heater 21 remains unchanged. When the temperature of the demineralized water is greater than 147 °C, the heater 21 is turned off.

[0125] Circulate the demineralized water for 2 hours, observe that the temperature stabilizes at about 143 °C, slowly open the first valve 31 and the fifth valve 35, introduce molten urea, and discharge the mixed liquid of demineralized water and molten urea to the liquid discharge device 7 until the demineralized water is completely discharged. The qualified molten urea solution circulates in the bypass pipeline 2 and the main transfer pipeline 1.

[0126] After circulating the demineralized water for 2 hours, the mixed liquid of demineralized water and molten urea can also be discharged from the material receiving device 6.

[0127] 2) Stable operation stage:

[0128] During the stable operation stage of the transfer pump 11, the temperature of the molten urea fluid is about 144 °C; the first valve 31, the second valve 32, the third valve 33, and the fourth valve 34 are all in the open state, and the temperature control logic is the same as that in the start-up stage of the transfer pump 11.

[0129] Closely monitor the material temperature data at the input end of the transfer pump 11 through the temperature sensor 13, monitor the material pressure value at the output end of the transfer pump 11 through the pressure measuring device, and monitor the material flow value at the output end of the main transfer pipeline 1 through the flowmeter 15. If there is a pressure drop, a flow rate drop, or both occur simultaneously, and their average value is less than 10% of the normal value, an alarm signal is sent to the operator, and the operator needs to confirm on-site whether the transfer pump 11 is blocked; if the pump is blocked, the set temperature value can be adjusted to 147 °C or even higher.

[0130] 3) Transfer pump hot standby stage:

[0131] When the system other than the transfer pump 11 has a short-term shutdown, to avoid the cumbersome operations of starting and stopping the transfer pump 11, the first valve 31 and the second valve 32 can be closed, the opening degrees of the third valve 33 and the fourth valve 34 can be adjusted, and the transfer pump 11 drives the molten urea to circulate between the bypass pipeline 2 and the main transfer pipeline 1. The temperature control logic is the same as that in the start-up preheating stage. At this time, the set temperature can be adjusted to 143 °C.

[0132] 4) Long-term shutdown stage:

[0133] When the entire production device is planned to have a long-term shutdown, all the molten urea in the system should be drained in a timely manner. In theory, after all the molten urea in the system is drained uniformly, it should be rinsed with demineralized water.

[0134] If it is necessary to drain the transfer pump 11 separately, the following operations can be performed: close the first valve 31 and the second valve 32, the molten urea in the transfer pump 11 circulates in the closed annular pipeline, open the fifth valve 35, and drain most of the molten urea in the transfer pump 11 to the liquid discharge device 7. The transfer pump 11 has a short-term shutdown, demineralized water is injected into the buffer tank 22, and the mixed liquid of demineralized water and molten urea circulates between the bypass pipeline 2 and the main transfer pipeline 1 for 15 minutes and then is drained to the liquid discharge device 7.

[0135] The mixed liquid of demineralized water and molten urea can also be discharged to the material receiving device 6 through the second valve 32.

[0136] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes the inherent elements thereof. Without further limitation, the element defined by the statement "including a..." does not exclude the existence of additional identical elements in the process, method, article or device including the said element. In addition, the parts of the above technical solutions provided in the embodiments of the present application that are the same as the corresponding technical solutions in the prior art in terms of implementation principles are not described in detail to avoid excessive elaboration.

[0137] Specific examples are used in this article to elaborate on the principles and implementation manners of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principles of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A liquid material conveying device, characterized in that: It includes a main delivery pipeline; a delivery pump arranged on the main delivery pipeline; a bypass pipeline; a heater and an injection port for injecting reflux materials are arranged on the bypass pipeline; and a controller; The material input end and the material output end of the main conveying pipeline are respectively provided with a first valve and a second valve; the first end of the bypass pipeline is connected to the section between the first valve and the input end of the conveying pump on the main conveying pipeline; the second end of the bypass pipeline is connected to the section between the second valve and the output end of the conveying pump on the main conveying pipeline; The controller is used to control the opening and closing of the first valve and the second valve; When the first valve and the second valve are kept in a closed state, the bypass pipeline and the main delivery pipeline together form a closed annular pipeline, the delivery pump is used to drive the reflux material to circulate in the closed annular pipeline, and the heater is used to heat the reflux material so that the reflux material heats the delivery pump; When the first valve and the second valve are kept in an open state, the conveying pump is used to drive the material to be conveyed in the main conveying pipeline from the material input end to the material output end.

2. The liquid material conveying equipment according to claim 1, characterized in that: The reflux material is a solvent having a melting point lower than that of the material to be transported and a solubility in the material to be transported that is not less than a set solubility; And / or, the reflux material is the material to be transported.

3. The liquid material conveying equipment according to claim 1, characterized in that: The first end and the second end of the bypass pipeline are respectively provided with a third valve and a fourth valve; and the third valve, the fourth valve, the first valve and the second valve are all valves with adjustable openings.

4. The liquid material conveying equipment according to any one of claims 1 to 3, characterized in that: The material output end of the main conveying pipeline is connected to a material receiving device; the second valve is arranged between the material output end of the main conveying pipeline and the material receiving device; The material output end of the main conveying pipeline is also connected to a drainage device; the inlet of the drainage device is lower than the center height of the conveying pump; and a fifth valve is arranged between the second end of the main conveying pipeline and the drainage device.

5. The liquid material conveying equipment according to claim 1, characterized in that: The input end of the delivery pump is also provided with a temperature detection device; the output end of the delivery pump is also provided with a pressure measuring device and a flow meter.

6. A control method for liquid material conveying equipment, characterized in that: Applied to the liquid material conveying equipment according to any one of claims 1 to 5, the control method comprises: controlling the first valve and the second valve to remain closed; When the closed annular pipeline formed by the bypass pipeline and the main delivery pipeline is filled with reflux material, the delivery pump and the heater are controlled to start working, so as to drive the heated reflux material to circulate in the closed annular pipeline; When the delivery pump is heated to a set temperature value, the first valve and the second valve are controlled to open, so that the delivery pump drives the material to be delivered to flow in the main delivery pipeline.

7. The control method of liquid material conveying equipment according to claim 6, characterized in that: The process of heating the delivery pump to the set temperature value includes: Collecting temperature data of the reflux material at the input end of the delivery pump in real time; When the temperature data reaches the set temperature range, the heating power of the heater is kept unchanged, and the reflux material is continuously driven by the delivery pump to circulate in the closed annular pipeline for a set period of time; wherein the minimum boundary temperature of the set temperature range is higher than the melting point temperature of the material to be delivered.

8. The control method of liquid material conveying equipment according to claim 6, characterized in that: After controlling the first valve and the second valve to open, the method further includes: Controlling the first valve opening and the third valve opening to satisfy a first set opening ratio, and the second valve opening and the fourth valve opening to satisfy a second set opening ratio; Real-time detection of material temperature data at the input end of the delivery pump, material pressure data and material flow data at the output end of the delivery pump; Determine whether at least one of the fluid temperature data is less than a set temperature threshold, the fluid pressure data is less than a set pressure threshold, and the flow data is less than a set flow threshold; if so, increase the heating power of the heater and output an alarm prompt.

9. The control method of liquid material conveying equipment according to claim 6, characterized in that: After controlling the first valve and the second valve to open, the method further includes: When a long-time shutdown instruction is received, the first valve and the second valve are controlled to be closed, the fifth valve is opened, and the heater and the delivery pump are controlled to be shut down; When the material at the output end of the delivery pump is exhausted, the fifth valve is closed, and the closed annular pipeline is filled with the reflux material; wherein the reflux material is a solvent having a melting point lower than that of the material to be delivered and a solubility in the material to be delivered not less than a set solubility; Controlling the delivery pump and the heater to start working; When the reflux material circulates in the closed annular pipeline for a second set time, the delivery pump and the heater are controlled to stop working; The fifth valve is opened to allow the reflux material to flow into the drain device.

10. The control method of liquid material conveying equipment according to claim 6, characterized in that: After controlling the first valve and the second valve to open, the method further includes: When a short-time shutdown command is received, the first valve and the second valve are controlled to be closed, and the delivery pump and the heater are kept in a startup working state until a restart command is received, in which case the first valve and the second valve are controlled to be opened.

Images